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  1. Abnormal Breathing Patterns Predict Extubation Failure in Neurocritically Ill Patients

    PubMed Central

    Punj, Pragya; Nattanmai, Premkumar; George, Pravin

    2017-01-01

    In neurologically injured patients, predictors for extubation success are not well defined. Abnormal breathing patterns may result from the underlying neurological injury. We present three patients with abnormal breathing patterns highlighting failure of successful extubation as a result of these neurologically driven breathing patterns. Recognizing abnormal breathing patterns may be predictive of extubation failure and thus need to be considered as part of extubation readiness. PMID:28348899

  2. Predicting extubation failure in blunt trauma patients with pulmonary contusion.

    PubMed

    Bilello, John F; Davis, James W; Cagle, Kathleen M; Kaups, Krista L

    2013-08-01

    The need for reintubation after weaning from mechanical ventilation (extubation failure) is associated with increased morbidity and mortality. In blunt trauma patients with pulmonary contusion, factors predicting successful weaning have not been reliably defined. The purpose of this study was to identify criteria predicting successful extubation in these patients. Retrospective review during a 10-year period at a Level 1 trauma center was performed. A total of 173 extubations in 163 blunt trauma patients with pulmonary contusion requiring mechanical ventilation. Exclusion criteria include Glasgow Coma Scale (GCS) score of less than 9T before extubation, successful use of noninvasive positive-pressure ventilation after extubation, quadriplegia, and preextubation FIO2 of greater than 0.5. Data included age, Injury Severity Score (ISS), ventilator days, as well as GCS score, FIO2, the ratio of arterial oxygen tension to FIO2 (P/F ratio), and alveolar-arterial oxygen (A-a) difference at the time of extubation. Failure was defined as reintubation within 72 hours (excluding stridor or acute decline in GCS score). Mann-Whitney U-test, χ2 analysis, and logistic regression analysis determined variables associated with extubation failure. Odds ratios were used to compare P/F and A-a values associated with failed extubation. A total of 147 extubations (85%) were successful; 26 required reintubation. Patients did not differ by ISS, chest Abbreviated Injury Scale (AIS) score, presence of sternal or rib fractures, and admission pneumothorax or hemothorax. Increased age, A-a difference (≥ 120 mm Hg), and decreased P/F (<280) were associated with reintubation (p < 0.0001). By logistic regression analysis, P/F and A-a were independent variables for failed extubation; both remained independent risk factors when adjusted for age, ventilator days, GCS score, and preextubation FIO2. Using receiver operating characteristic curve inflection points for both P/F and A-a difference (area

  3. Accuracy of an Extubation Readiness Test in Predicting Successful Extubation in Children With Acute Respiratory Failure From Lower Respiratory Tract Disease.

    PubMed

    Faustino, Edward Vincent S; Gedeit, Rainer; Schwarz, Adam J; Asaro, Lisa A; Wypij, David; Curley, Martha A Q

    2017-01-01

    Identifying children ready for extubation is desirable to minimize morbidity and mortality associated with prolonged mechanical ventilation and extubation failure. We determined the accuracy of an extubation readiness test (Randomized Evaluation of Sedation Titration for Respiratory Failure extubation readiness test) in predicting successful extubation in children with acute respiratory failure from lower respiratory tract disease. Secondary analysis of data from the Randomized Evaluation of Sedation Titration for Respiratory Failure clinical trial, a pediatric multicenter cluster randomized trial of sedation. Seventeen PICUs in the intervention arm. Children 2 weeks to 17 years receiving invasive mechanical ventilation for lower respiratory tract disease. Extubation readiness test in which spontaneously breathing children with oxygenation index less than or equal to 6 were placed on FIO2 of 0.50, positive end-expiratory pressure of 5 cm H2O, and pressure support. Of 1,042 children, 444 (43%) passed their first extubation readiness test. Of these, 295 (66%) were extubated within 10 hours of starting the extubation readiness test, including 272 who were successfully extubated, for a positive predictive value of 92%. Among 861 children who were extubated for the first time within 10 hours of performing an extubation readiness test, 788 passed their extubation readiness test and 736 were successfully extubated for a positive predictive value of 93%. The median time of day for extubation with an extubation readiness test was 12:15 hours compared with 14:54 hours for extubation without an extubation readiness test within 10 hours (p < 0.001). In children with acute respiratory failure from lower respiratory tract disease, an extubation readiness test, as described, should be considered at least daily if the oxygenation index is less than or equal to 6. If the child passes the extubation readiness test, there is a high likelihood of successful extubation.

  4. Predictors of extubation failure in myasthenic crisis.

    PubMed

    Seneviratne, Janaka; Mandrekar, Jay; Wijdicks, Eelco F M; Rabinstein, Alejandro A

    2008-07-01

    The ideal timing for extubation of patients with myasthenic crisis (MC) and the factors that influence extubation outcome are not well established. To assess the risk of extubation failure in MC and to identify predictors of extubation failure. We reviewed consecutive episodes of MC treated with endotracheal intubation from January 1, 1987, through December 31, 2006. Mayo Clinic. Patients Forty patients with 46 episodes of MC underwent endotracheal intubation and mechanical ventilation. The main outcome measures were extubation failure and reintubation. Extubation failure was defined as reintubation, tracheostomy, or death while intubated. Reintubation was also analyzed as a separate end point. Univariate logistic regression was used to identify predictors of extubation failure and reintubation. Of the 46 episodes of MC, extubation failure occurred in 20 (44%), including 9 of 35 episodes (26%) of reintubation. Male sex, history of previous crisis, atelectasis, and intubation for more than 10 days were associated with extubation failure. Lower pH and lower forced vital capacity on the time of extubation, atelectasis, and bilevel intermittent positive airway pressure use after extubation predicted the need for reintubation. Atelectasis showed the strongest association with both end points. Extubation failure and reintubation were associated with significant prolongation in intensive care unit and hospital length of stay. Extubation failure is relatively common in patients with MC. Atelectasis is the strongest predictor of this complication.

  5. Etiology of extubation failure and the predictive value of the rapid shallow breathing index.

    PubMed

    Epstein, S K

    1995-08-01

    Failure of weaning from mechanical ventilation is thought to result from an imbalance between respiratory muscle capacity and respiratory demand. The ratio of respiratory rate to tidal volume (f/VT, rapid shallow breathing index) during spontaneous unsupported respiration increases when this imbalance exists, and may predict the success or failure of weaning from mechanical ventilation. Using f/VT, Yang and Tobin demonstrated a positive predictive value (PPV) of 0.78 (f/VT < or = 105 and weaning success) (1). To define the etiology of the 20% false-positive rate (FPR, f/VT < or = 105 and weaning failure), 94 patients who had an f/VT determined prior to extubation were studied prospectively. Of 84 patients with an f/VT < 100, 14 required reintubation within 72 h of extubation (FPR = 0.17, PPV = 0.83). Extubation in 13 of these 14 cases failed because of congestive heart failure, upper airway obstruction, aspiration, encephalopathy, or the development of a new pulmonary process. Only one patient needed reintubation solely because of the original respiratory process. Of 10 patients extubated with an f/VT > or = 100, four required reintubation, all because of the underlying respiratory process. This study confirms the high PPV for an f/VT < 100. The FPR of approximately 0.20 is best explained by extubation failure caused by processes for which f/VT is physiologically or temporally unlikely to predict success or failure. The negative predictive value (f/VT > or = 100 but extubation success) for f/VT may be lower than previously reported.

  6. Spontaneous breathing test in the prediction of extubation failure in the pediatric population.

    PubMed

    Nascimento, Milena Siciliano; Rebello, Celso Moura; Vale, Luciana Assis Pires Andrade; Santos, Érica; Prado, Cristiane do

    2017-01-01

    To assess whether the spontaneous breathing test can predict the extubation failure in pediatric population. A prospective and observational study that evaluated data of inpatients at the Pediatric Intensive Care Unit between May 2011 and August 2013, receiving mechanical ventilation for at least 24 hours followed by extubation. The patients were classified in two groups: Test Group, with patients extubated after spontaneous breathing test, and Control Group, with patients extubated without spontaneous breathing test. A total of 95 children were enrolled in the study, 71 in the Test Group and 24 in the Control Group. A direct comparison was made between the two groups regarding sex, age, mechanical ventilation time, indication to start mechanical ventilation and respiratory parameters before extubation in the Control Group, and before the spontaneous breathing test in the Test Group. There was no difference between the parameters evaluated. According to the analysis of probability of extubation failure between the two groups, the likelihood of extubation failure in the Control Group was 1,412 higher than in the Test Group, nevertheless, this range did not reach significance (p=0.706). This model was considered well-adjusted according to the Hosmer-Lemeshow test (p=0.758). The spontaneous breathing test was not able to predict the extubation failure in pediatric population. Avaliar se o teste de respiração espontânea pode ser utilizado para predizer falha da extubação na população pediátrica. Estudo prospectivo, observacional, no qual foram avaliados todos os pacientes internados no Centro de Terapia Intensiva Pediátrica, no período de maio de 2011 a agosto de 2013, que utilizaram ventilação mecânica por mais de 24 horas e que foram extubados. Os pacientes foram classificados em dois grupos: Grupo Teste, que incluiu os pacientes extubados depois do teste de respiração espontânea; e Grupo Controle, pacientes foram sem teste de respiração espont

  7. Usefulness of full outline of unresponsiveness score to predict extubation failure in intubated critically-ill patients: A pilot study

    PubMed Central

    Said, Tarek; Chaari, Anis; Hakim, Karim Abdel; Hamama, Dalia; Casey, William Francis

    2016-01-01

    Objective: To assess the usefulness of the full outline of unresponsiveness (FOUR) score in predicting extubation failure in critically ill intubated patients admitted with disturbed level of conscious in comparison with the Glasgow coma scale (GCS). Patients and Methods: All intubated critically ill patients with a disturbed level of consciousness were assessed using both the FOUR score and the GCS. The FOUR score and the GCS were compared regarding their predictive value for successful extubation at 14 days after intubation as a primary outcome measure. The 28-day mortality and the neurological outcome at 3 months were used as secondary outcome measures. Results: Eighty-six patients were included in the study. Median age was 63 (50–77) years. Sex–ratio (M/F) was 1.46. On admission, median GCS was 7 (3–10) while median FOUR score was 8.5 (2.3–11). A GCS ≤ 7 predicted the extubation failure at 14 days after intubation with a sensitivity of 88.5% and specificity of 68.3%, whereas a FOUR score <10 predicted the same outcome with a sensitivity of 80.8% and a specificity of 81.7%. The areas under the curves was significantly higher with the FOUR score than with GCS (respectively 0.867 confidence interval [CI]: 95% [0790–0.944] and 0.832 CI: 95% [0.741–0.923]; P = 0.014). When calculated before extubation, FOUR score <12 predicted extubation failure with a sensitivity of 92.3% and a specificity of 85%, whereas a GCS <12 predicted the same outcome with a sensitivity of 73% and a specificity of 61.7%. Both scores had similar accuracy for predicting 28-day mortality and neurological outcome at 3 months. Conclusion: The FOUR score is superior to the GCS for the prediction of successful extubation of intubated critically ill patients. PMID:28149821

  8. Simple motor tasks independently predict extubation failure in critically ill neurological patients.

    PubMed

    Kutchak, Fernanda Machado; Rieder, Marcelo de Mello; Victorino, Josué Almeida; Meneguzzi, Carla; Poersch, Karla; Forgiarini, Luiz Alberto; Bianchin, Marino Muxfeldt

    2017-01-01

    To evaluate the usefulness of simple motor tasks such as hand grasping and tongue protrusion as predictors of extubation failure in critically ill neurological patients. This was a prospective cohort study conducted in the neurological ICU of a tertiary care hospital in the city of Porto Alegre, Brazil. Adult patients who had been intubated for neurological reasons and were eligible for weaning were included in the study. The ability of patients to perform simple motor tasks such as hand grasping and tongue protrusion was evaluated as a predictor of extubation failure. Data regarding duration of mechanical ventilation, length of ICU stay, length of hospital stay, mortality, and incidence of ventilator-associated pneumonia were collected. A total of 132 intubated patients who had been receiving mechanical ventilation for at least 24 h and who passed a spontaneous breathing trial were included in the analysis. Logistic regression showed that patient inability to grasp the hand of the examiner (relative risk = 1.57; 95% CI: 1.01-2.44; p < 0.045) and protrude the tongue (relative risk = 6.84; 95% CI: 2.49-18.8; p < 0.001) were independent risk factors for extubation failure. Acute Physiology and Chronic Health Evaluation II scores (p = 0.02), Glasgow Coma Scale scores at extubation (p < 0.001), eye opening response (p = 0.001), MIP (p < 0.001), MEP (p = 0.006), and the rapid shallow breathing index (p = 0.03) were significantly different between the failed extubation and successful extubation groups. The inability to follow simple motor commands is predictive of extubation failure in critically ill neurological patients. Hand grasping and tongue protrusion on command might be quick and easy bedside tests to identify neurocritical care patients who are candidates for extubation. Avaliar a utilidade de tarefas motoras simples, tais como preensão de mão e protrusão da língua, para predizer extubação malsucedida em pacientes neurológicos críticos. Estudo

  9. Modified rapid shallow breathing index adjusted with anthropometric parameters increases predictive power for extubation failure compared with the unmodified index in postcardiac surgery patients.

    PubMed

    Takaki, Shunsuke; Kadiman, Suhaini Bin; Tahir, Sharifah Suraya; Ariff, M Hassan; Kurahashi, Kiyoyasu; Goto, Takahisa

    2015-02-01

    The aim of this study was to determine the best predictors of successful extubation after cardiac surgery, by modifying the rapid shallow breathing index (RSBI) based on patients' anthropometric parameters. Single-center prospective observational study. Two general intensive care units at a single research institute. Patients who had undergone uncomplicated cardiac surgery. None. The following parameters were investigated in conjunction with modification of the RSBI: Actual body weight (ABW), predicted body weight, ideal body weight, body mass index (BMI), and body surface area. Using the first set of patient data, RSBI threshold and modified RSBI for extubation failure were determined (threshold value; RSBI: 77 breaths/min (bpm)/L, RSBI adjusted with ABW: 5.0 bpm×kg/mL, RSBI adjusted with BMI: 2.0 bpm×BMI/mL). These threshold values for RSBI and RSBI adjusted with ABW or BMI were validated using the second set of patient data. Sensitivity values for RSBI, RSBI modified with ABW, and RSBI modified with BMI were 91%, 100%, and 100%, respectively. The corresponding specificity values were 89%, 92%, and 93%, and the corresponding receiver operator characteristic values were 0.951, 0.977, and 0.980, respectively. Modified RSBI adjusted based on ABW or BMI has greater predictive power than conventional RSBI. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. The endotracheal tube air leak test does not predict extubation outcome in critically ill pediatric patients.

    PubMed

    Wratney, Angela T; Benjamin, Daniel Kelly; Slonim, Anthony D; He, James; Hamel, Donna S; Cheifetz, Ira M

    2008-09-01

    Endotracheal tube air leak pressures are used to predict postextubation upper airway compromise such as stridor, upper airway obstruction, or risk of reintubation. To determine whether the absence of an endotracheal tube air leak (air leak test >/=30 cm H2O) measured during the course of mechanical ventilation predicts extubation failure in infants and children. Prospective, blinded cohort. Multidisciplinary pediatric intensive care unit of a university hospital. Patients younger than or equal to 18 yrs and intubated >/=24 hrs. The pressure required to produce an audible endotracheal tube air leak was measured within 12 hrs of intubation and extubation. Unless prescribed by the medical care team, patients did not receive neuromuscular blocking agents during air leak test measurements. The need for reintubation (i.e., extubation failure) was recorded during the 24-hr postextubation period. Seventy-four patients were enrolled resulting in 59 observed extubation trials. The extubation failure rate was 15.3% (9 of 59). Seven patients were treated for postextubation stridor. Extubation failure was associated with a longer median length of ventilation, 177 vs. 78 hrs, p = 0.03. Extubation success was associated with the use of postextubation noninvasive ventilation (p = 0.04). The air leak was absent for the duration of mechanical ventilation (i.e., >/=30 cm H2O at intubation and extubation) in ten patients. Absence of the air leak did not predict extubation failure (negative predictive value 27%, 95% confidence interval 6-60). The air leak test was >/=30 cm H2O before extubation in 47% (28 of 59) of patients yet 23 patients extubated successfully (negative predictive value 18%). An endotracheal tube air leak pressure >/=30 cm H2O measured in the nonparalyzed patient before extubation or for the duration of mechanical ventilation was common and did not predict an increased risk for extubation failure. Pediatric patients who are clinically identified as candidates for an

  11. Predicting Extubation Outcome by Cough Peak Flow Measured Using a Built-in Ventilator Flow Meter.

    PubMed

    Gobert, Florent; Yonis, Hodane; Tapponnier, Romain; Fernandez, Raul; Labaune, Marie-Aude; Burle, Jean-François; Barbier, Jack; Vincent, Bernard; Cleyet, Maria; Richard, Jean-Christophe; Guérin, Claude

    2017-09-12

    Successful weaning from mechanical ventilation depends on the patient's ability to cough efficiently. Cough peak flow (CPF) could predict extubation success using a dedicated flow meter but required patient disconnection. We aimed to predict extubation outcome using an overall model, including cough performance assessed by a ventilator flow meter. This was a prospective observational study conducted from November 2014 to October 2015. Before and after a spontaneous breathing trial, subjects were encouraged to cough as strongly as possible before freezing the ventilator screen to assess CPF and tidal volume (VT) in the preceding inspiration. Early extubation success rate was defined as the proportion of subjects not re-intubated 48h after extubation. Diagnostic performance of CPF and VT was assessed by using the area under the curve of the receiver operating characteristic curve. Cut-off values for CPF and VT were defined according to median values and used to describe the performance of a predictive test combining them with risk factors of early extubation failure. Among 673 subjects admitted, 92 had a cough assessment before extubation. For the 81 subjects with early extubation success, the median CPF was -67.7L/min, and median VT was 0.646L. For the 11 subjects with early extubation failure, the median CPF was -57.3L/min, and median VT was 0.448L. Area under the curve was 0.61 (95% CI 0.37-0.83) for CPF and 0.64 (95% CI 0.42-0.84) for CPF/VT combined. After dichotomization (CPF < -60L/min or VT> 0.55L), there was a synergistic effect to predict early extubation success (P < .001). The predictive value of success reached 94.2% for CPF/VT combined. The overall model including pH before extubation < 7.45 reached a 66.7% predictive value of failure. CPF measured using the flow meter of an ICU ventilator was able to predict extubation success and to build a composite score to predict extubation failure. The results were close to that found in previous studies that

  12. Association of Extubation Failure and Functional Outcomes in Patients with Acute Neurologic Illness.

    PubMed

    Rishi, Muhammad Adeel; Kashyap, Rahul; Wilson, Gregory; Schenck, Louis; Hocker, Sara

    2016-04-01

    An association between extubation failure and neurologic and functional outcomes in patients with primary neurologic illness has not been investigated rigorously. We plan to conduct a retrospective chart review to study this association. A total of 949 unique patients intubated and ventilated for at least 48 h in Neuro ICU (NICU) were obtained. Extubation failure was defined as need for reintubation within 48 h of initial extubation. Independent and dependent association between extubation failure and clinical parameters was assessed. The patients had a median age [interquartile range (IQR)] of 58.5 (23.0) years. 60.5% were male and 81.9% were Caucasian. Extubation failure occurred in 108 (12.8%) patients. There was no difference in age, APACHE 3 score, FOUR score, or GCS score of patients at ICU admission between those who experienced extubation failure and those who did not. Extubation failure was associated with longer NICU and hospital LOS [median (IQR); 13.7 (11.3) vs. 9.1(8.2) days, P < 0.01 and 24.5 (20.0) vs. 16.8 (16.7) days, P < 0.01]. Patients with extubation failure had worse functional outcomes at 6 months as measured by the modified Rankin score [MRS; median (IQR), 5.0 (2.0) vs. 4.0 (3.0), P < 0.01]. After adjusting for confounders, extubation failure was associated with longer hospital and ICU LOS and worse functional outcomes. In patients with acute neurological illness, extubation failure is associated with longer ICU and hospital stays but does not impact hospital mortality. Patients with extubation failure may experience a worsening of their functional status over time.

  13. Extubation Failure Is Associated With Increased Mortality Following First Stage Single Ventricle Reconstruction Operation.

    PubMed

    Scodellaro, Thomas; McKenzie, Jane M; d'Udekem, Yves; Butt, Warwick; Namachivayam, Siva P

    2017-09-15

    To identify the prevalence, causes, risk factors, and outcomes associated with extubation failure following first stage single ventricle reconstruction surgery. Retrospective cohort analysis of neonates who underwent a first stage single ventricle reconstruction operation. Extubation failure was defined as endotracheal reintubation within 48 hours of first extubation attempt. The Royal Children's Hospital, Melbourne. Data were collected for all infants who underwent a Norwood or Damus-Kaye-Stansel procedure between 2005 and 2014 at our institution. None. Extubation failure occurred in 23 of 137 neonates (16.8%; 95% CI, 11.0-24.1%) who underwent a trial of extubation. Overall, 42 patients (30.7%) were extubated to room air, 88 (64.2%) to nasal continuous positive airway pressure, and seven (5.1%) to high-flow nasal cannulae, though there was no major difference in extubation failure rates between these three groups (p = 0.37). The median time to reintubation was 16.7 hours (interquartile range, 3.2-35.2), and male infants failed extubation more frequently (63.2% vs 87.0%; p = 0.02), although age, gestation, weight, cardiac diagnosis (hypoplastic left heart syndrome vs other single ventricle conditions), shunt type (modified Blalock-Taussig vs right ventricle-pulmonary artery shunt), intraoperative perfusion times, preextubation mechanical ventilation duration, preextubation acid-base status, and postoperative fluid balance were not related to extubation outcome. Infants who failed extubation had a higher intensive care mortality (19.4% vs 3.5%; p = 0.03) and in-hospital mortality (30.4% vs 6.1%; p < 0.001). There is a high prevalence of extubation failure following first stage single ventricle reconstruction, and this is associated with considerably worse patient outcomes. The high prevalence and also the wide variation in rates of extubation failure in reported literature provide with an opportunity for implementation of quality assurance activities to minimize

  14. Predictors of extubation failure and reintubation in newborn infants subjected to mechanical ventilation

    PubMed Central

    Costa, Ana Cristina de Oliveira; Schettino, Renata de Carvalho; Ferreira, Sandra Clecêncio

    2014-01-01

    Objective To identify risk factors for extubation failure and reintubation in newborn infants subjected to mechanical ventilation and to establish whether ventilation parameters and blood gas analysis behave as predictors of those outcomes. Methods Prospective study conducted at a neonatal intensive care unit from May to November 2011. A total of 176 infants of both genders subjected to mechanical ventilation were assessed after extubation. Extubation failure was defined as the need to resume mechanical ventilation within less than 72 hours. Reintubation was defined as the need to reintubate the infants any time after the first 72 hours. Results Based on the univariate analysis, the variables gestational age <28 weeks, birth weight <1,000g and low Apgar scores were associated with extubation failure and reintubation. Based on the multivariate analysis, the variables length of mechanical ventilation (days), potential of hydrogen (pH) and partial pressure of oxygen (pO2) remained associated with extubation failure, and the five-minute Apgar score and age at extubation were associated with reintubation. Conclusion Low five-minute Apgar scores, age at extubation, length of mechanical ventilation, acid-base disorders and hyperoxia exhibited associations with the investigated outcomes of extubation failure and reintubation. PMID:24770689

  15. Do clinical parameters predict first planned extubation outcome in the pediatric intensive care unit?

    PubMed

    Laham, James L; Breheny, Patrick J; Rush, Amanda

    2015-02-01

    There is absence of evidence-based guidelines to determine extubation readiness in the pediatric intensive care unit (PICU). Evaluate our practice of determining extubation readiness based on physician judgment of preextubation ventilator settings, blood gas analysis, and other factors potentially affecting extubation outcome. Prospective cohort study from August 2010 to April 2012. Academic, multidisciplinary PICU. A total of 319 PICU patients undergoing first planned extubation attempt. None. Determine the extubation success rate and evaluate factors potentially affecting extubation outcome. The PICU length of stay (LOS) and cost were also recorded. Subgroup analysis was performed based on days of mechanical ventilation (MV). A total of 319 consecutive patients underwent first planned extubation attempt with a 91% success rate. Factors associated with extubation failure were the length of MV (P < .0001, odds ratio [OR] 2.20); age (P = .02, OR 0.54); preextubation steroids (P = .04, OR 2.40); and postextubation stridor (P < .01, OR 3.40). Ventilator settings and blood gas results had no association with extubation outcome with 1 exception, ventilator rates ≤ 8 were associated with extubation failure in patients with ≤1 day of MV. Extubation failure was associated with prolonged PICU LOS and excess cost, with failures staying 14 days longer (P < .0001) and costing 3.2 time more (P < .0001) than successes. Physician judgment to determine extubation readiness led to a first planned extubation success rate of 91%. Age and the length of MV were primary risk factors for failed extubation. In patients with ≤1 day of MV, our findings suggest that confidence in extubation readiness following weaning to low ventilator rates may not be justified. Furthermore, reliance on preextubation ventilator settings and blood gas results to determine extubation readiness may lead to unnecessary prolongation of MV, thereby increasing the PICU LOS and excess cost. These findings are

  16. Perioperative Predictors of Extubation Failure and the Effect on Clinical Outcome After Infratentorial Craniotomy.

    PubMed

    Cai, Ye-Hua; Wang, Hai-Tang; Zhou, Jian-Xin

    2016-07-12

    BACKGROUND The purpose of the study was to analyze the risk factors for failed extubation in subjects submitted to infratentorial craniotomy. MATERIAL AND METHODS Patients aged over 18 years who received infratentorial craniotomy for brain tumor resection were consecutively included in this study. Perioperative variables were collected and analyzed. Univariate analyses and multiple logistic regression were used to derive factors related to failed extubation. Patients had follow-up care until either out of hospital or death. RESULTS Throughout the course of the study, 2118 patients were eligible and 94 (4.4%) suffered from extubation failure at some point during their hospital stay. Five factors were recognized as independent risk factors for postoperative failed extubation: craniotomy history, preoperative lower cranial nerve dysfunction, tumor size, tumor position, and maximum change in blood pressure (BP) during the operation. Failed extubation was related to a higher incidence rate of pneumonia, mortality, unfavorable Glasgow Outcome Scale score, longer stay in the neuro-intensive care unit (ICU) and hospitalization, and higher hospitalization costs compared with successful extubation. CONCLUSIONS History of craniotomy, preoperative lower cranial nerve dysfunction, tumor size, tumor position, and maximum change in BP during the operation were independent risk factors related to postoperative failed extubation in patients submitted to infratentorial craniotomy. Extubation failure raises the incidences of postoperative pneumonia, mortality, and higher hospitalization costs, and prolongs neuro-ICU and postoperative length of stay.

  17. Establishing failure predictors for the planned extubation of overweight and obese patients.

    PubMed

    Chao, Chien-Ming; Lai, Chih-Cheng; Cheng, Ai-Chin; Chiang, Shyh-Ren; Liu, Wei-Lun; Ho, Chung-Han; Hsing, Shu-Chen; Chen, Chin-Ming; Cheng, Kuo-Chen

    2017-01-01

    We investigated failure predictors for the planned extubation of overweight (body mass index [BMI] = 25.0-29.9) and obese (BMI ≥ 30) patients. All patients admitted to the adult intensive care unit (ICU) of a tertiary hospital in Taiwan were identified. They had all undergone endotracheal intubation for > 48 h and were candidates for extubation. During the study, 595 patients (overweight = 458 [77%]); obese = 137 [23%]) with planned extubation after weaning were included in the analysis; extubation failed in 34 patients (5.7%). Their mean BMI was 28.5 ± 3.8. Only BMI and age were significantly different between overweight and obese patients. The mortality rate for ICU patients was 0.8%, and 2.9% for inpatients during days 1-28; the overall in-hospital mortality rate was 8.4%. Failed Extubation group patients were significantly older, had more end-stage renal disease (ESRD), more cardiovascular system-related respiratory failure, higher maximal inspiratory pressure (MIP), lower maximal expiratory pressure (MEP), higher blood urea nitrogen, and higher ICU- and 28-day mortality rates than did the Successful Extubation group. Multivariate logistic regression showed that cardiovascular-related respiratory failure (odds ratio [OR]: 2.60; 95% [confidence interval] CI: 1.16-5.80), ESRD (OR: 14.00; 95% CI: 6.25-31.35), and MIP levels (OR: 0.94; 95% CI: 0.90-0.97) were associated with extubation failure. We conclude that the extubation failure risk in overweight and obese patients was associated with cardiovascular system-related respiratory failure, ESRD, and low MIP levels.

  18. Noninvasive ventilation immediately after extubation improves weaning outcome after acute respiratory failure: a randomized controlled trial

    PubMed Central

    2013-01-01

    Introduction Noninvasive ventilation (NIV), as a weaning-facilitating strategy in predominantly chronic obstructive pulmonary disease (COPD) mechanically ventilated patients, is associated with reduced ventilator-associated pneumonia, total duration of mechanical ventilation, length of intensive care unit (ICU) and hospital stay, and mortality. However, this benefit after planned extubation in patients with acute respiratory failure of various etiologies remains to be elucidated. The aim of this study was to determine the efficacy of NIV applied immediately after planned extubation in contrast to oxygen mask (OM) in patients with acute respiratory failure (ARF). Methods A randomized, prospective, controlled, unblinded clinical study in a single center of a 24-bed adult general ICU in a university hospital was carried out in a 12-month period. Included patients met extubation criteria with at least 72 hours of mechanical ventilation due to acute respiratory failure, after following the ICU weaning protocol. Patients were randomized immediately before elective extubation, being randomly allocated to one of the study groups: NIV or OM. We compared both groups regarding gas exchange 15 minutes, 2 hours, and 24 hours after extubation, reintubation rate after 48 hours, duration of mechanical ventilation, ICU length of stay, and hospital mortality. Results Forty patients were randomized to receive NIV (20 patients) or OM (20 patients) after the following extubation criteria were met: pressure support (PSV) of 7 cm H2O, positive end-expiratory pressure (PEEP) of 5 cm H2O, oxygen inspiratory fraction (FiO2) ≤ 40%, arterial oxygen saturation (SaO2) ≥ 90%, and ratio of respiratory rate and tidal volume in liters (f/TV) < 105. Comparing the 20 patients (NIV) with the 18 patients (OM) that finished the study 48 hours after extubation, the rate of reintubation in NIV group was 5% and 39% in OM group (P = 0.016). Relative risk for reintubation was 0.13 (CI = 0.017 to 0

  19. Can Machine Learning Methods Predict Extubation Outcome in Premature Infants as well as Clinicians?

    PubMed Central

    Mueller, Martina; Almeida, Jonas S.; Stanislaus, Romesh; Wagner, Carol L.

    2014-01-01

    Rationale Though treatment of the prematurely born infant breathing with assistance of a mechanical ventilator has much advanced in the past decades, predicting extubation outcome at a given point in time remains challenging. Numerous studies have been conducted to identify predictors for extubation outcome; however, the rate of infants failing extubation attempts has not declined. Objective To develop a decision-support tool for the prediction of extubation outcome in premature infants using a set of machine learning algorithms Methods A dataset assembled from 486 premature infants on mechanical ventilation was used to develop predictive models using machine learning algorithms such as artificial neural networks (ANN), support vector machine (SVM), naïve Bayesian classifier (NBC), boosted decision trees (BDT), and multivariable logistic regression (MLR). Performance of all models was evaluated using area under the curve (AUC). Results For some of the models (ANN, MLR and NBC) results were satisfactory (AUC: 0.63–0.76); however, two algorithms (SVM and BDT) showed poor performance with AUCs of ~0.5. Conclusion Clinician's predictions still outperform machine learning due to the complexity of the data and contextual information that may not be captured in clinical data used as input for the development of the machine learning algorithms. Inclusion of preprocessing steps in future studies may improve the performance of prediction models. PMID:25419493

  20. Can Machine Learning Methods Predict Extubation Outcome in Premature Infants as well as Clinicians?

    PubMed

    Mueller, Martina; Almeida, Jonas S; Stanislaus, Romesh; Wagner, Carol L

    2013-01-01

    Though treatment of the prematurely born infant breathing with assistance of a mechanical ventilator has much advanced in the past decades, predicting extubation outcome at a given point in time remains challenging. Numerous studies have been conducted to identify predictors for extubation outcome; however, the rate of infants failing extubation attempts has not declined. To develop a decision-support tool for the prediction of extubation outcome in premature infants using a set of machine learning algorithms. A dataset assembled from 486 premature infants on mechanical ventilation was used to develop predictive models using machine learning algorithms such as artificial neural networks (ANN), support vector machine (SVM), naïve Bayesian classifier (NBC), boosted decision trees (BDT), and multivariable logistic regression (MLR). Performance of all models was evaluated using area under the curve (AUC). For some of the models (ANN, MLR and NBC) results were satisfactory (AUC: 0.63-0.76); however, two algorithms (SVM and BDT) showed poor performance with AUCs of ~0.5. Clinician's predictions still outperform machine learning due to the complexity of the data and contextual information that may not be captured in clinical data used as input for the development of the machine learning algorithms. Inclusion of preprocessing steps in future studies may improve the performance of prediction models.

  1. Weaning and extubation readiness in pediatric patients.

    PubMed

    Newth, Christopher J L; Venkataraman, Shekhar; Willson, Douglas F; Meert, Kathleen L; Harrison, Rick; Dean, J Michael; Pollack, Murray; Zimmerman, Jerry; Anand, Kanwaljeet J S; Carcillo, Joseph A; Nicholson, Carol E

    2009-01-01

    A systematic review of weaning and extubation for pediatric patients on mechanical ventilation. Pediatric and adult literature, English language. Invited review. Literature review using National Library of Medicine PubMed from January 1972 until April 2008, earlier cross-referenced article citations, the Cochrane Database of Systematic Reviews, and the Internet. Despite the importance of minimizing time on mechanical ventilation, only limited guidance on weaning and extubation is available from the pediatric literature. A significant proportion of patients being evaluated for weaning are actually ready for extubation, suggesting that weaning is often not considered early enough in the course of ventilation. Indications for extubation are even less clear, although a trial of spontaneous breathing would seem a prerequisite. Several indices have been developed in an attempt to predict weaning and extubation success but the available literature would suggest they offer no improvement over clinical judgment. Extubation failure rates range from 2% to 20% and bear little relationship to the duration of mechanical ventilation. Upper airway obstruction is the single most common cause of extubation failure. A reliable method of assessing readiness for weaning and predicting extubation success is not evident from the pediatric literature.

  2. Prediction of extubation outcome: a randomised, controlled trial with automatic tube compensation vs. pressure support ventilation

    PubMed Central

    Cohen, Jonathan; Shapiro, Maury; Grozovski, Elad; Fox, Ben; Lev, Shaul; Singer, Pierre

    2009-01-01

    Introduction Tolerance of a spontaneous breathing trial is an evidence-based strategy to predict successful weaning from mechanical ventilation. Some patients may not tolerate the trial because of the respiratory load imposed by the endotracheal tube, so varying levels of respiratory support are widely used during the trial. Automatic tube compensation (ATC), specifically developed to overcome the imposed work of breathing because of artificial airways, appears ideally suited for the weaning process. We further evaluated the use of ATC in this setting. Methods In a prospective study, patients who had received mechanical ventilation for more than 24 hours and met defined criteria for a weaning trial, underwent a one-hour spontaneous breathing trial with either ATC (n = 87) or pressure support ventilation (PSV; n = 93). Those tolerating the trial were immediately extubated. The primary outcome measure was the ability to maintain spontaneous, unassisted breathing for more than 48 hours after extubation. In addition, we measured the frequency/tidal volume ratio (f/VT) both with (ATC-assisted) and without ATC (unassisted-f/VT) at the start of the breathing trial as a pretrial predictor of extubation outcome. Results There were no significant differences in any of the baseline characteristics between the two groups apart from a significantly higher Acute Physiology and Chronic Health Evaluation (APACHE) II score in the ATC group (p = 0.009). In the PSV group, 13 of 93 (14%) patients failed the breathing trial compared with only 6 of 87 (6%) in the ATC group; this observed 8% difference, however, did not reach statistical significance (p = 0.12). The rate of reintubation was not different between the groups (total group = 17.3%; ATC = 18.4% vs. PSV = 12.9%, p = 0.43). The percentage of patients who remained extubated for more than 48 hours was similar in both groups (ATC = 74.7% vs. PSV = 73.1%; p = 0.81). This represented a positive predictive value for PSV of 0.85 and

  3. Clinical prediction of weaning and extubation in Australian and New Zealand intensive care units.

    PubMed

    Rose, L; Presneill, J J

    2011-07-01

    Our objective was to describe, in Australian and New Zealand adult intensive care units, the relative frequency in which various clinical criteria were used to predict weaning and extubation, and the weaning methods employed. Participant intensivists at 55 intensive care units completed a self-administered questionnaire, using visual analogue scales (0 = not at all predictive, 10 = perfectly predictive, not used = null score) to record the perceived utility of 30 potential predictors. Survey response rate was 71% (164/230). Those variables thought most predictive of weaning readiness were respiratory rate (median score 8.0, interquartile range 7.0 to 8.6) effective cough (7.3, 5.9 to 8.2) and pressure support setting (7.2, 6.0 to 8.0). The most highly rated predictors of extubation success were effective cough (8.0, 7.0 to 9.0), respiratory rate (8.0, 7.0 to 8.5) and Glasgow Coma Score (7.9, 6.1 to 8.3). Variables perceived least predictive of weaning and extubation success were P0.1, Acute Physiological and Chronic Health Evaluation score II, mean arterial pressure, electrolytes and maximum inspiratory pressure (individual median scores < 5). Most popular clinical criteria were those perceived to have high predictive accuracy, both for weaning (respiratory rate 96%, pressure support setting 94% and Glasgow coma score 91%) and extubation readiness (respiratory rate 98%, effective cough 94% and Glasgow Coma Score 92%). Weaning mostly employed pressure support ventilation (55%), with less use of synchronised intermittent mandatory ventilation (32%) and spontaneous breathing trials (13%). Classic ventilatory performance predictors including respiratory rate and effective cough were reported to be of greater clinical utility than other more recently proposed measures.

  4. Lower interbreath interval complexity is associated with extubation failure in mechanically ventilated patients during spontaneous breathing trials.

    PubMed

    White, Christopher E; Batchinsky, Andriy I; Necsoiu, Corina; Nguyen, Ruth; Walker, Kerfoot P; Chung, Kevin K; Wolf, Steven E; Cancio, Leopoldo C

    2010-06-01

    To determine whether lower complexity of interbreath interval as measured with nonlinear analysis techniques will identify patients who fail to separate from mechanical ventilation after 30-minute spontaneous breathing trials (SBTs). Respiratory waveforms from SBT of patients in surgical or burn intensive care units were recorded for later analysis. The decision to extubate was made by attending physician. Extubated patients were observed for 48 hours; during this time, reintubation or noninvasive positive pressure ventilation was considered as a failure. Analysis of waveform data by software was performed post hoc. Sample entropy (SampEn) and other nonlinear measures were 48 hours of extubation. Thirty-two patients (24 burn, 8 trauma/surgical admissions; mean age, 40.2 +/- 16.9 years; 26 men and 6 women) who were intubated >24 hours were extubated after SBT. Twenty-four patients were successfully separated from mechanical ventilation and eight failed. Age, gender, and mechanism of injury did not influence outcome. SampEn calculated for the two groups presented in this study was different with the cohort that failed extubation having a lower mean value (1.35 +/- 0.39 vs. 1.87 +/- 0.27; p < 0.001). Other nonlinear metrics were moved in concert with SampEn. The stationarity in the respiratory signal was not different between groups. In intubated patients, the interbreath interval in those who were successfully separated from mechanical ventilation was more irregular than those who failed, as measured by nonlinear techniques. When available at bedside, these metrics may be useful markers of pulmonary health and assist in clinical decision making.

  5. Lower Interbreath Interval Complexity Is Associated With Extubation Failure in Mechanically Ventilated Patients During Spontaneous Breathing Trials

    DTIC Science & Technology

    2010-06-01

    patient tolerated the SBT, then measurement of respiratory rate (RR), rapid shallow breathing index (RSBI), and negative inspiratory force ( NIF ) were...no deaths in either cohort during the study period. The characteristics of the two groups, along with RR, duration of IBI, NIF , and RSBI calculated... NIF , and RSBI did not differ between groups, and that all subjects who were extubated had weaning parameters predictive of success. To explore the

  6. Use of naloxone to minimize extubation failure after premedication for INSURE procedure in preterm neonates.

    PubMed

    Elmekkawi, A; Abdelgadir, D; Van Dyk, J; Choudhury, J; Dunn, M

    2016-01-01

    A new guideline for the early respiratory management of preterm infants that included early nCPAP and INSURE was recently introduced in our NICU. This case series describes the clinical courses of a group of preterm infants managed according to this guideline, and reports the rates of successful extubation within 30 minutes of surfactant administration with and without the use of naloxone and adverse events encountered. Descriptive case series of all preterm babies admitted to our unit who were candidates for INSURE procedure with premedication from August 2012 to August 2013. A total of 31 infants were included with a mean birth weight of 1178 grams and a mean gestational age of 28.4 weeks. Twelve out of thirteen (92%) infants in the naloxone group were extubated within 30 minutes of surfactant administration while only 12/18 (67%) in the non-naloxone group were extubated within the same time frame. No adverse reactions were noted with naloxone usage in this context. Naloxone can be effective in reversing the respiratory depressive effect of analgesic premedication and in turn facilitates expeditious extubation in some preterm infants intubated for INSURE procedure.

  7. Association Between Deep Sedation from Continuous Intravenous Sedatives and Extubation Failures in Mechanically Ventilated Patients in the Pediatric Intensive Care Unit.

    PubMed

    Schultheis, Jennifer M; Heath, Travis S; Turner, David A

    2017-01-01

    The primary objective of this study was to determine whether an association exists between deep sedation from continuous infusion sedatives and extubation failures in mechanically ventilated children. Secondary outcomes evaluated risk factors associated with deep sedation. This was a retrospective cohort study conducted between January 1, 2009, and October 31, 2012, in the pediatric intensive care unit (PICU) at Duke Children's Hospital. Patients were included in the study if they had been admitted to the PICU, had been mechanically ventilated for ≥48 hours, and had received at least one continuous infusion benzodiazepine and/or opioid infusion for ≥24 hours. Patients were separated into 2 groups: those deeply sedated and those not deeply sedated. Deep sedation was defined as having at least one documented State Behavioral Scale (SBS) of -3 or -2 within 72 hours prior to planned extubation. A total of 108 patients were included in the analysis. Both groups were well matched with regard to baseline characteristics. For the primary outcome, there was no difference in extubation failures in those who were deeply sedated compared to those not deeply sedated (14 patients [22.6%] versus 7 patients [15.2%], respectively; p = 0.33). After adjusting for potential risk factors, patients with a higher weight percentile for age (odds ratio [OR] 1.02; 95% confidence interval [CI] 1.00-1.03), lower Glasgow Coma Score (GCS) score prior to intubation (OR 0.85; 95% CI 0.74-0.97), and larger maximum benzodiazepine dose (OR 1.93; 95% CI 1.01-3.71) were associated with greater odds of deep sedation. A higher GCS prior to intubation was significantly associated with increased odds of extubation failure (OR 1.19; 95% CI 1.02-1.39). While there was no statistically significant difference in extubation failures between the 2 groups included in this study, considering the severe consequences of extubation failure, the numerical difference reported may be clinically important.

  8. Diaphragmatic dysfunction in patients with ICU-acquired weakness and its impact on extubation failure.

    PubMed

    Jung, Boris; Moury, Pierre Henri; Mahul, Martin; de Jong, Audrey; Galia, Fabrice; Prades, Albert; Albaladejo, Pierre; Chanques, Gerald; Molinari, Nicolas; Jaber, Samir

    2016-05-01

    Diaphragm function is rarely studied in intensive care patients with unit-acquired weakness (ICUAW) in whom weaning from mechanical ventilation is challenging. The aim of the present study was to evaluate the diaphragm function and the outcome using a multimodal approach in ICUAW patients. Patients were eligible if they were diagnosed for ICUAW [Medical Research Council (MRC) Score <48], mechanically ventilated for at least 48 h and were undergoing a spontaneous breathing trial. Diaphragm function was assessed using magnetic stimulation of the phrenic nerves (change in endotracheal tube pressure), maximal inspiratory pressure and ultrasonographically (thickening fraction). Diaphragmatic dysfunction was defined by a change in endotracheal tube pressure below 11 cmH2O. The endpoints were to describe the correlation between diaphragm function and ICUAW and its impact on extubation. Among 185 consecutive patients ventilated for more than 48 h, 40 (22 %) with a MRC score of 31 [20-36] were included. Diaphragm dysfunction was observed with ICUAW in 32 patients (80 %). Change in endotracheal tube pressure and MRC score were not correlated. Maximal inspiratory pressure was correlated with change in endotracheal tube pressure after magnetic stimulation of the phrenic nerves (r = 0.43; p = 0.005) and MRC score (r = 0.34; p = 0.02). Thickening fraction was less than 20 % in 70 % of the patients and was statistically correlated with change in endotracheal tube pressure (r = 0.4; p = 0.02) but not with MRC score. Half of the patients could be extubated without needing reintubation within 72 h. Diaphragm dysfunction is frequent in patients with ICU-acquired weakness (80 %) but poorly correlated with the ICU-acquired weakness MRC score. Half of the patients with ICU-acquired weakness were successfully extubated. Half of the patients who failed the weaning process died during the ICU stay.

  9. Preoperative and Intraoperative Predictive Factors of Immediate Extubation After Neonatal Cardiac Surgery.

    PubMed

    Varghese, Joby; Kutty, Shelby; Abdullah, Ibrahim; Hall, Sandra; Shostrom, Valerie; Hammel, James M

    2016-11-01

    We sought to identify preoperative and intraoperative predictors of immediate extubation (IE) after open heart surgery in neonates. The effect of IE on the postoperative intensive care unit (ICU) length of stay (LOS), cost of postoperative ICU care, operating room turnover, and reintubation rates was assessed. Patients younger than 31 days who underwent cardiac surgery with cardiopulmonary bypass (January 2010 to December 2013) at a tertiary-care children's hospital were studied. Immediate extubation was defined as successful extubation before termination of anesthetic care. Data on preoperative and intraoperative variables were compared using descriptive, bivariate, and multivariate statistics to identify the predictors of IE. Propensity scores were used to assess effects of IE on ICU LOS, the cost of ICU care, reintubation rates, and operating room turnover time. One hundred forty-eight procedures done at a median age of 7 days resulted in 45 IEs (30.4%). The IE rate was 22.2% with single-ventricle heart disease. Independent predictors of IE were the absence of the need for preoperative ventilatory assistance, higher gestational age, anesthesiologist, and shorter cardiopulmonary bypass. Immediate extubation was associated with shorter ICU LOS (8.3 versus 12.7 days; p < 0.0001) and lower cost of ICU care (mean postoperative ICU charges, $157,449 versus $198,197; p < 0.0001) with no significant difference in the probability of reintubation (p = 0.7). Immediate extubation was associated with longer operating room turnover time (38.4 versus 46.7 minutes; p = 0.009). Immediate extubation was accomplished in 30.4% of neonates undergoing open heart surgery involving cardiopulmonary bypass. Immediate extubation was associated with lesser ICU LOS, postoperative ICU costs, and minimal increase in operating room turnover time, but without an increase in reintubation rates. Low gestational age, preoperative ventilatory support requirement, and prolonged cardiopulmonary

  10. Establishing predictors for successfully planned endotracheal extubation.

    PubMed

    Lai, Chih-Cheng; Chen, Chin-Ming; Chiang, Shyh-Ren; Liu, Wei-Lun; Weng, Shih-Feng; Sung, Mei-I; Hsing, Shu-Chen; Cheng, Kuo-Chen

    2016-10-01

    The aim of this study was to establish predictors for successfully planned extubation, which can be followed by medical personnel. The patients who were admitted to the adult intensive care unit of a tertiary hospital and met the following criteria between January 2005 and December 2014 were collected retrospectively: intubation > 48 hours; and candidate for extubation. The patient characteristics, including disease severity, rapid shallow breath index (RSBI), maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), cuff leak test (CLT) before extubation, and outcome, were recorded. The CLT was classified as 2+ with audible flow without a stethoscope, 1+ with audible flow using a stethoscope, and negative (N) with no audible flow, even with a stethoscope. Failure to extubate was defined as reintubation within 48 hours. In total, 6583 patients were enrolled and 403 patients (6.1%) had extubation failures. Male patients dominated the patient cohort (4261 [64.7%]). The mean age was 64.5±16.3 years. The overall in-hospital mortality rate was 11.3%. The extubation failure rate for females was greater than males (7.7% vs 5.3%, P < 0.001). The group of patients who failed extubation were older (66.7 ± 14.4 vs 64.3 ± 16.4, P = 0.002), had higher APACHE II scores (16.8 ± 7.6 vs 15.9 ± 7.8, P = 0.023), lower coma scales (10.3 ± 3.7 vs 10.8 ± 3.7, P = 0.07), a higher RSBI (69.9 ± 37.3 vs 58.6 ± 30.3, P < 0.001), a lower MIP, and MEP (-35.6 ± 15.3 vs -37.8 ± 14.6, P = 0.0001 and 49.6 ± 28.4 vs 58.6 ± 30.2, P < 0.001, respectively), and a higher mortality rate (25.6% vs 10.5%, P < 0.001) compared to the successful extubation group. Based on multivariate logistic regression, a CLT of 2+ (odds ratio [OR] = 2.07, P < 0.001), a MEP ≥ 55 cmH2O (OR = 1.73, P < 0.001), and a RSBI < 68 breath/min/ml (OR = 1.57, P < 0.001) were independent predictors for successful

  11. Markers of Successful Extubation in Extremely Preterm Infants, and Morbidity After Failed Extubation.

    PubMed

    Chawla, Sanjay; Natarajan, Girija; Shankaran, Seetha; Carper, Benjamin; Brion, Luc P; Keszler, Martin; Carlo, Waldemar A; Ambalavanan, Namasivayam; Gantz, Marie G; Das, Abhik; Finer, Neil; Goldberg, Ronald N; Cotten, C Michael; Higgins, Rosemary D

    2017-06-06

    To identify variables associated with successful elective extubation, and to determine neonatal morbidities associated with extubation failure in extremely preterm neonates. This study was a secondary analysis of the National Institute of Child Health and Human Development Neonatal Research Network's Surfactant, Positive Pressure, and Oxygenation Randomized Trial that included extremely preterm infants born at 24(0/7) to 27(6/7) weeks' gestation. Patients were randomized either to a permissive ventilatory strategy (continuous positive airway pressure group) or intubation followed by early surfactant (surfactant group). There were prespecified intubation and extubation criteria. Extubation failure was defined as reintubation within 5 days of extubation. Of 1316 infants in the trial, 1071 were eligible; 926 infants had data available on extubation status; 538 were successful and 388 failed extubation. The rate of successful extubation was 50% (188/374) in the continuous positive airway pressure group and 63% (350/552) in the surfactant group. Successful extubation was associated with higher 5-minute Apgar score, and pH prior to extubation, lower peak fraction of inspired oxygen within the first 24 hours of age and prior to extubation, lower partial pressure of carbon dioxide prior to extubation, and non-small for gestational age status after adjustment for the randomization group assignment. Infants who failed extubation had higher adjusted rates of mortality (OR 2.89), bronchopulmonary dysplasia (OR 3.06), and death/ bronchopulmonary dysplasia (OR 3.27). Higher 5-minute Apgar score, and pH prior to extubation, lower peak fraction of inspired oxygen within first 24 hours of age, lower partial pressure of carbon dioxide and fraction of inspired oxygen prior to extubation, and nonsmall for gestational age status were associated with successful extubation. Failed extubation was associated with significantly higher likelihood of mortality and morbidities. Clinical

  12. Predictive Factors for Efficacy and Safety of Prophylactic Theophylline for Extubation in Infants with Apnea of Prematurity

    PubMed Central

    Orita, Yuji; Mitarai, Fumi; Ishitsuka, Yoichi; Irikura, Mitsuru; Shimodozono, Yoshihiro; Douchi, Tsutomu; Takeda, Yasuo; Irie, Tetsumi

    2016-01-01

    Purpose This study aimed to evaluate predictive factors involved in efficacy and safety in Japanese infants who received theophylline therapy to prevent apnea of prematurity (AOP) after weaning from mechanical ventilation. Methods We retrospectively reviewed the medical records of infants who were administered intravenous aminophylline (theophylline ethylenediamine) for AOP at the neonatal intensive care unit, Kagoshima University Hospital, Japan, between January 2009 and June 2013. Results A total of 100 infants were evaluated as two separate groups in terms of efficacy and safety of theophylline. Sixty-seven (67.0%) infants had effective theophylline therapy. Multivariate logistic regression analysis showed that gestational age at birth was significant, with an odds ratio of 0.59 (p < 0.001). Receiver operating characteristic analysis showed that the cut-off value was 31.1 weeks old for predicting the efficacy of theophylline (specificity, 66.7%; sensitivity, 86.6%; p < 0.001; area under the curve, 0.750; 95% confidence interval, 0.45–0.74). Adverse reactions were identified in 21 (21.0%) infants. Multivariate logistic regression analysis showed that the number of days of theophylline administration from birth was associated with an increased risk of adverse reactions after theophylline administration (p = 0.01). Conclusions Physicians need to be aware of the possibility that theophylline fails to produce therapeutic effects for extubation in infants aged less than 31.1 weeks old, and adverse reactions can easily develop when theophylline is administered soon after birth. PMID:27388444

  13. Predictive Factors for Efficacy and Safety of Prophylactic Theophylline for Extubation in Infants with Apnea of Prematurity.

    PubMed

    Kondo, Tomoko; Kondo, Yuki; Orita, Yuji; Mitarai, Fumi; Ishitsuka, Yoichi; Irikura, Mitsuru; Shimodozono, Yoshihiro; Douchi, Tsutomu; Takeda, Yasuo; Irie, Tetsumi

    2016-01-01

    This study aimed to evaluate predictive factors involved in efficacy and safety in Japanese infants who received theophylline therapy to prevent apnea of prematurity (AOP) after weaning from mechanical ventilation. We retrospectively reviewed the medical records of infants who were administered intravenous aminophylline (theophylline ethylenediamine) for AOP at the neonatal intensive care unit, Kagoshima University Hospital, Japan, between January 2009 and June 2013. A total of 100 infants were evaluated as two separate groups in terms of efficacy and safety of theophylline. Sixty-seven (67.0%) infants had effective theophylline therapy. Multivariate logistic regression analysis showed that gestational age at birth was significant, with an odds ratio of 0.59 (p < 0.001). Receiver operating characteristic analysis showed that the cut-off value was 31.1 weeks old for predicting the efficacy of theophylline (specificity, 66.7%; sensitivity, 86.6%; p < 0.001; area under the curve, 0.750; 95% confidence interval, 0.45-0.74). Adverse reactions were identified in 21 (21.0%) infants. Multivariate logistic regression analysis showed that the number of days of theophylline administration from birth was associated with an increased risk of adverse reactions after theophylline administration (p = 0.01). Physicians need to be aware of the possibility that theophylline fails to produce therapeutic effects for extubation in infants aged less than 31.1 weeks old, and adverse reactions can easily develop when theophylline is administered soon after birth.

  14. Tension-time index as a predictor of extubation outcome in ventilated children.

    PubMed

    Harikumar, Gopinathannair; Egberongbe, Yaya; Nadel, Simon; Wheatley, Elizabeth; Moxham, John; Greenough, Anne; Rafferty, Gerrard F

    2009-11-15

    Indices that assess the load on the respiratory muscles, such as the tension-time index (TTI), may predict extubation outcome. To evaluate the performance of a noninvasive assessment of TTI, the respiratory muscle tension time index (TTmus), by comparison to that of the diaphragm tension time index (TTdi) and other predictors of extubation outcome in ventilated children. Eighty children (median [range] age 2.1 yr [0.15-16]) admitted to pediatric intensive care units at King's College and St Mary's Hospitals who required mechanical ventilation for more than 24 hours were studied. TTmus, maximal inspiratory pressure, respiratory drive, respiratory system mechanics, and functional residual capacity using a helium dilution technique, the rapid shallow breathing and CROP indices (compliance, rate, oxygenation, and pressure) indexed for body weight were measured and standard clinical data recorded in all patients. TTdi was measured in 28 of the 80 children using balloon catheters. Eight children (three in the TTdi group) failed extubation. TTmus (0.199 vs. 0.09) and TTdi (0.157 vs. 0.07) were significantly higher in children who failed extubation. TTmus greater than 0.18 (n = 80) and TTdi greater than 0.15 (n = 28) had sensitivities and specificities of 100% in predicting extubation failure. The other predictors performed less well. Invasive and noninvasive measurements of TTI may provide accurate prediction of extubation outcome in mechanically ventilated children.

  15. Data Driven Device Failure Prediction

    DTIC Science & Technology

    2016-09-15

    solution is to use statistical machine learning to predict failure. However, since failure is still a relatively rare event, obtaining labelled training...52 15 Pre-Update, Memory Leak Support Vector Machine (SVM...37 9 Pre-Update, Memory Leak, Support Vector Machine (SVM) Confusion Matrix

  16. Detecting failure of climate predictions

    USGS Publications Warehouse

    Runge, Michael C.; Stroeve, Julienne C.; Barrett, Andrew P.; McDonald-Madden, Eve

    2016-01-01

    The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty1, 2. Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies3. Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

  17. Detecting failure of climate predictions

    NASA Astrophysics Data System (ADS)

    Runge, Michael C.; Stroeve, Julienne C.; Barrett, Andrew P.; McDonald-Madden, Eve

    2016-09-01

    The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty. Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies. Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

  18. Predictors of operating room extubation in adult cardiac surgery.

    PubMed

    Subramaniam, Kathirvel; DeAndrade, Diana S; Mandell, Daniel R; Althouse, Andrew D; Manmohan, Rajan; Esper, Stephen A; Varga, Jeffrey M; Badhwar, Vinay

    2017-06-13

    The primary objective of the study was to identify perioperative factors associated with successful immediate extubation in the operating room after adult cardiac surgery. The secondary objective was to derive a simplified predictive scoring system to guide clinicians in operating room extubation. All 1518 patients in this retrospective cohort study underwent standardized fast-track cardiac anesthetic protocol during adult cardiac surgery. Perioperative variables between patients who had successful extubation in the operating room versus in the intensive care unit were retrospectively analyzed using both univariate and multivariable logistic regression analyses. A predictive score of successful operating room extubation was constructed from the multivariable results of 800 patients (derivation set), and the scoring system was further tested using a validation set of 398 patients. Younger age, lower body mass index, higher preoperative serum albumin, absence of chronic lung disease and diabetes, less-invasive surgical approach, isolated coronary bypass surgery, elective surgery, and lower doses of intraoperative intravenous fentanyl were independently associated with higher probability of operating room extubation. The extubation prediction score created in a derivation set of patients performed well in the validation set. Patient scores less than 0 had a minimal probability of successful operating room extubation. Operating room extubation was highly predicted with scores of 5 or greater. Perioperative factors that are independently associated with successful operating room extubation after adult cardiac operations were identified, and an operating room extubation prediction scoring system was validated. This scoring system may be used to guide safe operating room extubation after cardiac operations. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  19. All India Difficult Airway Association 2016 guidelines for the management of anticipated difficult extubation

    PubMed Central

    Kundra, Pankaj; Garg, Rakesh; Patwa, Apeksh; Ahmed, Syed Moied; Ramkumar, Venkateswaran; Shah, Amit; Divatia, Jigeeshu Vasishtha; Shetty, Sumalatha Radhakrishna; Raveendra, Ubaradka S; Doctor, Jeson R; Pawar, Dilip K; Singaravelu, Ramesh; Das, Sabyasachi; Myatra, Sheila Nainan

    2016-01-01

    Extubation has an important role in optimal patient recovery in the perioperative period. The All India Difficult Airway Association (AIDAA) reiterates that extubation is as important as intubation and requires proper planning. AIDAA has formulated an algorithm based on the current evidence, member survey and expert opinion to incorporate all patients of difficult extubation for a successful extubation. The algorithm is not designed for a routine extubation in a normal airway without any associated comorbidity. Extubation remains an elective procedure, and hence, patient assessment including concerns related to airway needs to be done and an extubation strategy must be planned before extubation. Extubation planning would broadly be dependent on preventing reflex responses (haemodynamic and cardiovascular), presence of difficult airway at initial airway management, delayed recovery after the surgical intervention or airway difficulty due to pre-existing diseases. At times, maintaining a patent airway may become difficult either due to direct handling during initial airway management or due to surgical intervention. This also mandates a careful planning before extubation to avoid extubation failure. Certain long-standing diseases such as goitre or presence of obesity and obstructive sleep apnoea may have increased chances of airway collapse. These patients require planned extubation strategies for extubation. This would avoid airway collapse leading to airway obstruction and its sequelae. AIDAA suggests that the extubation plan would be based on assessment of the airway. Patients requiring suppression of haemodynamic responses would require awake extubation with pharmacological attenuation or extubation under deep anaesthesia using supraglottic devices as bridge. Patients with difficult airway (before surgery or after surgical intervention) or delayed recovery or difficulty due to pre-existing diseases would require step-wise approach. Oxygen supplementation should

  20. Predicting Electronic Failure from Smoke

    SciTech Connect

    Tanaka, T.J.

    1999-01-15

    Smoke can cause electronic equipment to fail through increased leakage currents and shorts. Sandia National Laboratories is studying the increased leakage currents caused by smoke with varying characteristics. The objective is to develop models to predict the failure of electronic equipment exposed to smoke. This requires the collection of data on the conductivity of smoke and knowledge of critical electrical systems that control high-consequence operations. We have found that conductivity is a function of the type of fuel, how it is burned, and smoke density. Video recordings of highly biased dc circuits exposed in a test chamber show that during a fire, smoke is attracted to high voltages and can build fragile carbon bridges that conduct leakage currents. The movement of air breaks the bridges, so the conductivity decreases after the fire is extinguished and the test chamber is vented. During the fire, however, electronic equipment may not operate correctly, leading to problems for critical operations dependent on electronic control. The potential for electronic failure is highly dependent on the type of electrical circuit, and Sandia National Laboratories plans to include electrical circuit modeling in the failure models.

  1. Prediction of Failure at University--or Failure of Prediction?

    ERIC Educational Resources Information Center

    Nisbet, J.; Welsh, J.

    1976-01-01

    The validity of a procedure for identifying students at risk of failure on the basis of first term examination results was checked by following up 188 students at risk, from a total of 1902 in Aberdeen University Arts Faculty in session 1974-75. (Editor)

  2. Failure mode analysis to predict product reliability.

    NASA Technical Reports Server (NTRS)

    Zemanick, P. P.

    1972-01-01

    The failure mode analysis (FMA) is described as a design tool to predict and improve product reliability. The objectives of the failure mode analysis are presented as they influence component design, configuration selection, the product test program, the quality assurance plan, and engineering analysis priorities. The detailed mechanics of performing a failure mode analysis are discussed, including one suggested format. Some practical difficulties of implementation are indicated, drawn from experience with preparing FMAs on the nuclear rocket engine program.

  3. Uncertainties in container failure time predictions

    SciTech Connect

    Williford, R.E.

    1990-01-01

    Stochastic variations in the local chemical environment of a geologic waste repository can cause corresponding variations in container corrosion rates and failure times, and thus in radionuclide release rates. This paper addresses how well the future variations in repository chemistries must be known in order to predict container failure times that are bounded by a finite time period within the repository lifetime. Preliminary results indicate that a 5000 year scatter in predicted container failure times requires that repository chemistries be known to within {plus minus}10% over the repository lifetime. These are small uncertainties compared to current estimates. 9 refs., 3 figs.

  4. Prediction of Cascading Failures in Spatial Networks.

    PubMed

    Shunkun, Yang; Jiaquan, Zhang; Dan, Lu

    2016-01-01

    Cascading overload failures are widely found in large-scale parallel systems and remain a major threat to system reliability; therefore, they are of great concern to maintainers and managers of different systems. Accurate cascading failure prediction can provide useful information to help control networks. However, for a large, gradually growing network with increasing complexity, it is often impractical to explore the behavior of a single node from the perspective of failure propagation. Fortunately, overload failures that propagate through a network exhibit certain spatial-temporal correlations, which allows the study of a group of nodes that share common spatial and temporal characteristics. Therefore, in this study, we seek to predict the failure rates of nodes in a given group using machine-learning methods. We simulated overload failure propagations in a weighted lattice network that start with a center attack and predicted the failure percentages of different groups of nodes that are separated by a given distance. The experimental results of a feedforward neural network (FNN), a recurrent neural network (RNN) and support vector regression (SVR) all show that these different models can accurately predict the similar behavior of nodes in a given group during cascading overload propagation.

  5. Nebulized racemic epinephrine for extubation of newborn infants.

    PubMed

    Davies, M W; Davis, P G

    2002-01-01

    Following a period of mechanical ventilation, post-extubation upper airway obstruction can occur in newborn infants, especially after prolonged, traumatic or multiple intubations. The subsequent increase in upper airway resistance may lead to respiratory insufficiency and failure of extubation. The vasoconstrictive properties of epinephrine, and its proven efficacy in the treatment of croup in infants, has led to the routine use of inhaled nebulized epinephrine immediately post-extubation in some neonatal units. It is also recommended for neonates with post-extubation tracheal obstruction and stridor in neonatal and respiratory textbooks and reviews. The primary objective was to assess whether nebulized epinephrine administered immediately after extubation in neonates weaned from IPPV decreases the need for subsequent additional respiratory support. Searches were of: MEDLINE from 1966 to September 2000; CINAHL from 1982 to September 2000; Current Contents from 1994 to September 2000; and the Cochrane Controlled Trials Register (Cochrane Library Issue 3, 2000). These searches were updated to September 2001 for this review update. Previous searches up to March 1999 included the Oxford Database of Perinatal Trials, expert informants and journal hand searching mainly in the English language, previous reviews including cross references, abstracts, and conference and symposia proceedings. All randomised and quasi-randomised control trials in which nebulized epinephrine was compared with placebo immediately post-extubation in newborn infants who have been weaned from IPPV and extubated, with regard to clinically important outcomes (i.e. need for additional respiratory support, increase in oxygen requirement, respiratory distress, stridor or the occurrence of side effects). No studies met our criteria for inclusion in this review. No studies were identified which looked at the effect of inhaled nebulized epinephrine on clinically important outcomes in infants being

  6. Nebulized racemic epinephrine for extubation of newborn infants.

    PubMed

    Davies, M W; Davis, P G

    2001-01-01

    Following a period of mechanical ventilation, post-extubation upper airway obstruction can occur in newborn infants, especially after prolonged, traumatic or multiple intubations. The subsequent increase in upper airway resistance may lead to respiratory insufficiency and failure of extubation. The vasoconstrictive properties of epinephrine, and its proven efficacy in the treatment of croup in infants, has led to the routine use of inhaled nebulised epinephrine immediately post-extubation in some neonatal units. It is also recommended for neonates with post-extubation tracheal obstruction and stridor in neonatal and respiratory textbooks and reviews. The primary objective was to assess whether nebulised epinephrine administered immediately after extubation in neonates weaned from IPPV decreases the need for subsequent additional respiratory support. Searches were made using MeSH search terms 'epinephrine' and 'exp infant, newborn'. Databases searched included: MEDLINE from1966 to September 2000; CINAHL from 1982 to September 2000; Current Contents from 1994 to September 2000; and the Cochrane Controlled Trials Register, The Cochrane Library 2000 Issue 3. Previous searches up to March 1999 have included the Oxford Database of Perinatal trials, expert informants and journal hand searching mainly in the English language, expert informant searches in the Japanese language by Prof. Ogawa, previous reviews including cross references, abstracts, and conference and symposia proceedings. All randomised and quasi-randomised control trials in which nebulised epinephrine was compared with placebo immediately post-extubation in newborn infants who have been weaned from IPPV and extubated, with regard to clinically important outcomes (i.e. need for additional respiratory support, increase in oxygen requirement, respiratory distress, stridor or the occurrence of side effects). No studies met our criteria for inclusion in this review. No studies were identified which looked at the

  7. Nebulized racemic epinephrine for extubation of newborn infants.

    PubMed

    Davies, M W; Davis, P G

    2000-01-01

    Following a period of mechanical ventilation, post-extubation upper airway obstruction can occur in newborn infants, especially after prolonged, traumatic or multiple intubations. The subsequent increase in upper airway resistance may lead to respiratory insufficiency and failure of extubation. The vasoconstrictive properties of epinephrine, and its proven efficacy in the treatment of croup in infants, has led to the routine use of inhaled nebulised epinephrine immediately post-extubation in some neonatal units. It is also recommended for neonates with post-extubation tracheal obstruction and stridor in neonatal and respiratory textbooks and reviews. The primary objective was to assess whether nebulised epinephrine administered immediately after extubation in neonates weaned from IPPV decreases the need for subsequent additional respiratory support. Searches were made of Medline (MeSH search terms 'epinephrine' and 'exp infant, newborn'), the Oxford Database of Perinatal trials, expert informants and journal hand searching mainly in the English language, expert informant searches in the Japanese language by Prof. Ogawa, previous reviews including cross references, abstracts, and conference and symposia proceedings. All randomised and quasi-randomised control trials in which nebulised epinephrine was compared with placebo immediately post-extubation in newborn infants who have been weaned from IPPV and extubated, with regard to clinically important outcomes (i.e. need for additional respiratory support, increase in oxygen requirement, respiratory distress, stridor or the occurrence of side effects). No studies met our criteria for inclusion in this review. No studies were identified which looked at the effect of inhaled nebulised epinephrine on clinically important outcomes in infants being extubated. There is no evidence either supporting or refuting the use of inhaled nebulised racemic epinephrine in newborn infants. randomised controlled trials are needed

  8. Managing tracheal extubation in infants with stridor and congenital neuraxial anomalies

    PubMed Central

    Saigal, Deepti; Ganjoo, Pragati; Sharma, Megha U.; Singh, Daljit

    2016-01-01

    Stridor is a serious complication of congenital neuraxial anomalies, which though, can get completely resolved with early neurosurgical correction of the anomaly. However, stridor relief may or may not be achieved soon after surgery. Persistent postoperative stridor can potentially cause extubation failure that may be difficult to handle in small children. There are no extubation guidelines for difficult pediatric airways as yet, and fewer appropriate airway-assist devices for routine use. Management of an infant with occipital encephalocele, hydrocephalus and bilateral abductor vocal cord palsy, who developed post-extubation respiratory distress due to stridor is discussed, together with the relevant tracheal extubation issues in such cases. PMID:28217159

  9. Factors Predicting Meniscal Allograft Transplantation Failure

    PubMed Central

    Parkinson, Ben; Smith, Nicholas; Asplin, Laura; Thompson, Peter; Spalding, Tim

    2016-01-01

    Background: Meniscal allograft transplantation (MAT) is performed to improve symptoms and function in patients with a meniscal-deficient compartment of the knee. Numerous studies have shown a consistent improvement in patient-reported outcomes, but high failure rates have been reported by some studies. The typical patients undergoing MAT often have multiple other pathologies that require treatment at the time of surgery. The factors that predict failure of a meniscal allograft within this complex patient group are not clearly defined. Purpose: To determine predictors of MAT failure in a large series to refine the indications for surgery and better inform future patients. Study Design: Cohort study; Level of evidence, 3. Methods: All patients undergoing MAT at a single institution between May 2005 and May 2014 with a minimum of 1-year follow-up were prospectively evaluated and included in this study. Failure was defined as removal of the allograft, revision transplantation, or conversion to a joint replacement. Patients were grouped according to the articular cartilage status at the time of the index surgery: group 1, intact or partial-thickness chondral loss; group 2, full-thickness chondral loss 1 condyle; and group 3, full-thickness chondral loss both condyles. The Cox proportional hazards model was used to determine significant predictors of failure, independently of other factors. Kaplan-Meier survival curves were produced for overall survival and significant predictors of failure in the Cox proportional hazards model. Results: There were 125 consecutive MATs performed, with 1 patient lost to follow-up. The median follow-up was 3 years (range, 1-10 years). The 5-year graft survival for the entire cohort was 82% (group 1, 97%; group 2, 82%; group 3, 62%). The probability of failure in group 1 was 85% lower (95% CI, 13%-97%) than in group 3 at any time. The probability of failure with lateral allografts was 76% lower (95% CI, 16%-89%) than medial allografts at

  10. Role of Hematocrit Concentration on Successful Extubation in Critically Ill Patients in the Intensive Care Units.

    PubMed

    Beigmohammadi, Mohammad Taghi; Hussain Khan, Zahid; Samadi, Shahram; Mahmoodpoor, Ata; Fotouhi, Akbar; Rahimiforoushani, Abbas; Asadi Gharabaghi, Mehrnaz

    2016-02-01

    Hematocrit (Hct) is an important parameter for optimal oxygenation during discontinuation from ventilator, but there is no consensus about its concentration and effectiveness on successful extubation. The current study aimed to determine the role of Hct concentration on extubation failure in critically ill patients. The current prospective cohort study investigated the effect of age, gender and Hct level on successful extubation of 163 mechanically ventilated patients in Imam Khomeini hospital intensive care units (ICUs), Tehran, Iran. Following successful weaning process, the patients were classified into two groups on the basis of Hct level; 62 with an Hct level of 21% - 27% and the other 101 patients with Hct levels above 27%. The data were analyzed by chi-square test and multiple logistic regressions. A probability value of less than 0.05 was considered significant. There was no significant association between the level of Hct concentration and extubation failure (8.9% vs. 9.2%, P = 0.507). Gender and age were significantly associated with extubation failure (OR = 9.1, P = 0.034, OR = 12.5, P = 0.014, respectively). Although the differences between, before and after extubation of PaO2 and P/F ratio, were of significant values between the two different groups of Hct (P = 0.001, P = 0.004 respectively), they had no effect on the failure of extubation (P= 0.259, P = 0.403, respectively). Although some studies showed association between anemia and extubation failure, the current study could not confirm it. The study showed that males, regardless of the Hct level, had a better extubation success rate than those of females.

  11. Self-extubation Laryngeal Injuries at an Academic Tertiary Care Center: A Retrospective Pilot Study.

    PubMed

    Cohn, Jason E; Touati, Andrew; Lentner, Mark; Weitzel, Mark; Fisher, Casey; Sataloff, Robert T

    2017-07-01

    The purpose of this study is to identify laryngeal symptoms and injuries in self-extubated patients. A retrospective chart review was conducted to identify symptoms and clinical findings associated with self-extubation. A novel scoring system was developed and used to quantify these findings. Symptom score included all symptoms that patients reported after self-extubation. Clinical score consisted of laryngeal findings visualized on nasopharyngeal laryngoscopy. Finally, a total self-extubation score was calculated as the sum of the symptom and clinical scores. Additionally, duration of intubation and endotracheal tube size were correlated with these scores. Sixty (n = 60) patients who self-extubated in our institution's intensive care unit were identified. Average calculated symptom, clinical, and total self-extubation scores were 0.92, 1.43, and 2.35, respectively. The most common symptom observed was hoarseness (62%), while the most common clinical finding was posterior laryngeal edema (58%). A significant positive correlation was found between duration of intubation and both symptom score and total self-extubation score (r = 0.314, P = .008 and r = 0.223, P = .05, respectively). Symptom score predicted clinical score with a significant positive correlation present (r = 0.278, P = .02). This study demonstrates that the majority of self-extubated patients have laryngeal symptoms and clinical findings. A comprehensive, multidisciplinary evaluation is warranted for self-extubations.

  12. Evaluating Risk Factors for Pediatric Post-extubation Upper Airway Obstruction Using a Physiology-based Tool

    PubMed Central

    Hotz, Justin; Morzov, Rica; Flink, Rutger; Kamerkar, Asavari; Ross, Patrick A.; Newth, Christopher J. L.

    2016-01-01

    Rationale: Subglottic edema is the most common cause of pediatric extubation failure, but few studies have confirmed risk factors or prevention strategies. This may be due to subjective assessment of stridor or inability to differentiate supraglottic from subglottic disease. Objectives: Objective 1 was to assess the utility of calibrated respiratory inductance plethysmography (RIP) and esophageal manometry to identify clinically significant post-extubation upper airway obstruction (UAO) and differentiate subglottic from supraglottic UAO. Objective 2 was to identify risk factors for subglottic UAO, stratified by cuffed versus uncuffed endotracheal tubes (ETTs). Methods: We conducted a single-center prospective study of children receiving mechanical ventilation. UAO was defined by inspiratory flow limitation (measured by RIP and esophageal manometry) and classified as subglottic or supraglottic based on airway maneuver response. Clinicians performed simultaneous blinded clinical UAO assessment at the bedside. Measurements and Main Results: A total of 409 children were included, 98 of whom had post-extubation UAO and 49 (12%) of whom were subglottic. The reintubation rate was 34 (8.3%) of 409, with 14 (41%) of these 34 attributable to subglottic UAO. Five minutes after extubation, RIP and esophageal manometry better identified patients who subsequently received UAO treatment than clinical UAO assessment (P < 0.006). Risk factors independently associated with subglottic UAO included low cuff leak volume or high preextubation leak pressure, poor sedation, and preexisting UAO (P < 0.04) for cuffed ETTs; and age (range, 1 mo to 5 yr) for uncuffed ETTs (P < 0.04). For uncuffed ETTs, the presence or absence of preextubation leak was not associated with subglottic UAO. Conclusions: RIP and esophageal manometry can objectively identify subglottic UAO after extubation. Using this technique, preextubation leak pressures or cuff leak volumes predict subglottic UAO in

  13. Methods, apparatus and system for notification of predictable memory failure

    DOEpatents

    Cher, Chen-Yong; Andrade Costa, Carlos H.; Park, Yoonho; Rosenburg, Bryan S.; Ryu, Kyung D.

    2017-01-03

    A method for providing notification of a predictable memory failure includes the steps of: obtaining information regarding at least one condition associated with a memory; calculating a memory failure probability as a function of the obtained information; calculating a failure probability threshold; and generating a signal when the memory failure probability exceeds the failure probability threshold, the signal being indicative of a predicted future memory failure.

  14. Prediction for human motion tracking failures.

    PubMed

    Dockstader, Shiloh L; Imennov, Nikita S

    2006-02-01

    We propose a new and effective method of predicting tracking failures and apply it to the robust analysis of gait and human motion. We define a tracking failure as an event and describe its temporal characteristics using a hidden Markov model (HMM). We represent the human body using a three-dimensional, multicomponent structural model, where each component is designed to independently allow the extraction of certain gait variables. To enable a fault-tolerant tracking and feature extraction system, we introduce a single HMM for each element of the structural model, trained on previous examples of tracking failures. The algorithm derives vector observations for each Markov model using the time-varying noise covariance matrices of the structural model parameters. When transformed with a logarithmic function, the conditional output probability of each HMM is shown to have a causal relationship with imminent tracking failures. We demonstrate the effectiveness of the proposed approach on a variety of multiview video sequences of complex human motion.

  15. Progress in Predicting Rock-Slope Failures

    NASA Astrophysics Data System (ADS)

    Korup, O.

    2015-12-01

    Recent research on predicting landslides has seen a massive increase in statistical and computational methods that are largely adapted from the fields of machine learning and data mining. Judging from a sample of some 150 recent scientific papers, the gross majority of the reported success rates of these statistical methods are overwhelmingly high and promising at between 71% and 98%. Perhaps surprisingly, though, the death toll and damage from landslides has remained elevated in the early 21st century, so that reliably predicting the occurrence of rock-slope failures without overfitting our models remains challenging. Here I review some of the recent advances in this field, and show how novel results from landslide seismology and landslide sedimentology have promoted our ability of detecting large rock-slope failures in mountainous terrain. Several new detailed investigations of the internal nature of large rockslide deposits, for example, help to reduce the confusion potential with macroscopically similar moraine debris, or microscopically similar fault breccia. I further outline some of the limitations of empirical models that use rainfall intensity-duration thresholds for landslide early warning, and of multivariate methods concerned with mapping landslide susceptibility at the regional scale. I conclude by discussing the occurrence of 'black swans' such as long-runout rock-ice avalanches in size distributions of rock-slope failures, and their implications for quantitative hazard appraisals.

  16. Extubation with or without spontaneous breathing trial.

    PubMed

    Wang, Jing; Ma, Yingmin; Fang, Qiuhong

    2013-12-01

    Purpose- To evaluate whether spontaneous breathing trials (SBTs) are necessary when extubating critical care patients. Methods- A prospective, randomized, double-blind study was performed in adult patients supported by mechanical ventilation for at least 48 hours in the general intensive care unit of a teaching hospital. Patients ready for weaning were randomly assigned to either the SBT group (extubation with an SBT) or the no-SBT group (extubation without an SBT). Patients in the SBT group who tolerated SBT underwent immediate extubation. Patients in the no-SBT group who met the weaning readiness criteria underwent extubation without an SBT. The primary outcome measure was a successful extubation or the ability to maintain spontaneous breathing for 48 hours after extubation. Results- A total of 139 adult patients were enrolled. No significant difference in the demographic, respiratory, and hemodynamic characteristics was indicated between the groups at the end of weaning readiness assessment. Successful extubation was achieved in 56 of 61 patients (91.8%) in the SBT group and 54 of 60 patients (90.0%) in the no-SBT group. In the SBT and no-SBT groups, 5 (8.2%) and 6 (10.0%) patients, respectively, needed reintubation; 7 (11.5%) and 9 (15.0%) patients, respectively, required noninvasive ventilation after extubation. In-hospital mortality did not differ significantly between the groups. Conclusion- Intensive care patients can be extubated successfully without an SBT.

  17. [Predictors of extubation failure in neurosurgical patients].

    PubMed

    León-Gutiérrez, Marco Antonio; Tanus-Hajj, Janet; Sánchez-Hurtado, Luis Alejandro

    2016-01-01

    Introducción: la información con respecto a los factores que afectan el éxito de la extubación en pacientes neuroquirúrgicos es limitada; por lo tanto, es necesario determinar los factores que inciden en esta condición. Métodos: estudio prospectivo, longitudinal, observacional y comparativo en pacientes neuroquirúrgicos con criterios para la extubación. En aquellos que presentaron fracaso se analizó el número de aspiraciones endotraqueales en las 24 horas previas a la extubación, la presencia del reflejo de tos, los días de estancia y de ventilación mecánica. Resultados: se incluyeron 70 pacientes en el estudio, de los cuales el 11.4 % presentó fracaso de la extubación y los factores asociados fueron la realización de 6 aspiraciones de secreciones endotraqueales 24 horas previas a la extubación (con una razón de riesgo [RR] = 1.88, intervalo de confianza [IC] al 95 % = 1.14-3.09, p 0.01), 7 días de ventilación mecánica (RR = 1.31, IC 95 % = 1.08-1.57, p 0.005) y 7.5 días de estancia (RR = 1.24, IC 95 % = 1.05-1.47, p 0.01). Conclusión: hacer seis o más aspiraciones de secreciones endotraqueales durante las 24 horas previas a la extubación es un factor de riesgo para el fracaso de la extubación de pacientes neuroquirúrgicos.

  18. Postoperative respiratory failure after cardiac surgery: use of noninvasive ventilation.

    PubMed

    García-Delgado, Manuel; Navarrete, Inés; García-Palma, Maria José; Colmenero, Manuel

    2012-06-01

    To analyze the use of noninvasive ventilation (NIV) in respiratory failure after extubation in patients after cardiac surgery, the factors associated with respiratory failure, and the need for reintubation. Retrospective observational study. Intensive care unit in a university hospital. Patients (n = 63) with respiratory failure after extubation after cardiac surgery over a 3-year period. Mechanical NIV. Demographic and surgical data, respiratory history, causes of postoperative respiratory failure, durations of mechanical ventilation and spontaneous breathing, gas exchange values, and the mortality rate were recorded. Of 1,225 postsurgical patients, 63 (5.1%) underwent NIV for respiratory failure after extubation. The median time from extubation to the NIV application was 40 hours (18-96 hours). The most frequent cause of respiratory failure was lobar atelectasis (25.4%). The NIV failed in 52.4% of patients (33/63) who had a lower pH at 24 hours of treatment (7.35 v 7.42, p = 0.001) and a higher hospital mortality (51.5% v 6.7%, p = 0.001) than those in whom NIV was successful. An interval <24 hours from extubation to NIV was a predictive factor for NIV failure (odds ratio, 4.6; 95% confidence interval, 1.2-17.9), whereas obesity was associated with NIV success (odds ratio, 0.22; 95% confidence interval, 0.05-0.91). Reintubation was required in half of the NIV-treated patients and was associated with an increased hospital mortality rate. Early respiratory failure after extubation (≤24 hours) is a predictive factor for NIV failure. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Extubation to high-flow nasal cannula in critically ill surgical patients.

    PubMed

    Dhillon, Navpreet K; Smith, Eric J T; Ko, Ara; Harada, Megan Y; Polevoi, Danielle; Liang, Richard; Barmparas, Galinos; Ley, Eric J

    2017-09-01

    High-flow nasal cannula (HFNC) is increasingly used to reduce reintubations in patients with respiratory failure. Benefits include providing positive end expiratory pressure, reducing anatomical dead space, and decreasing work of breathing. We sought to compare outcomes of critically ill surgical patients extubated to HFNC versus conventional therapy. A retrospective review was conducted in the surgical intensive care unit of an academic center during August 2015 to February 2016. Data including demographics, ventilator days, oxygen therapy after extubation, reintubation rates, surgical intensive care unit and hospital length of stay, and mortality were collected. Self and palliative extubations were excluded. Characteristics and outcomes, with the primary outcome being reintubation, were compared between those extubated to HFNC versus cool mist/nasal cannula (CM/NC). Of the 184 patients analyzed, 46 were extubated to HFNC and 138 to CM/NC. Mean age and days on ventilation before extubation were 57.8 years and 4.3 days, respectively. Both cohorts were similar in age, sex, and had a similar prevalence of cardiopulmonary diagnoses at admission. Although prior to extubation HFNC had lengthier ventilation requirements (7.1 versus 3.4 days, P < 0.01) and ICU stays (7.8 versus 4.1 days, P < 0.01), the rate of reintubation was similar to CM/NC (6.5% versus 13.8%, P = 0.19). Multivariable analysis demonstrated HFNC to be associated with a lower risk of reintubation (adjusted odds ratio = 0.15, P = 0.02). Mortality rates were similar. Ventilated patients at risk for recurrent respiratory failure have reduced reintubation rates when extubated to HFNC. Patients with prolonged intubation or those with high-risk comorbidities may benefit from extubation to HFNC. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Effort test failure: toward a predictive model.

    PubMed

    Webb, James W; Batchelor, Jennifer; Meares, Susanne; Taylor, Alan; Marsh, Nigel V

    2012-01-01

    Predictors of effort test failure were examined in an archival sample of 555 traumatically brain-injured (TBI) adults. Logistic regression models were used to examine whether compensation-seeking, injury-related, psychological, demographic, and cultural factors predicted effort test failure (ETF). ETF was significantly associated with compensation-seeking (OR = 3.51, 95% CI [1.25, 9.79]), low education (OR:. 83 [.74, . 94]), self-reported mood disorder (OR: 5.53 [3.10, 9.85]), exaggerated displays of behavior (OR: 5.84 [2.15, 15.84]), psychotic illness (OR: 12.86 [3.21, 51.44]), being foreign-born (OR: 5.10 [2.35, 11.06]), having sustained a workplace accident (OR: 4.60 [2.40, 8.81]), and mild traumatic brain injury severity compared with very severe traumatic brain injury severity (OR: 0.37 [0.13, 0.995]). ETF was associated with a broader range of statistical predictors than has previously been identified and the relative importance of psychological and behavioral predictors of ETF was evident in the logistic regression model. Variables that might potentially extend the model of ETF are identified for future research efforts.

  1. Postoperative respiratory failure: pathogenesis, prediction, and prevention.

    PubMed

    Canet, Jaume; Gallart, Lluís

    2014-02-01

    This review discusses our present understanding of postoperative respiratory failure (PRF) pathogenesis, risk factors, and perioperative-risk reduction strategies. PRF, the most frequent postoperative pulmonary complication, is defined by impaired blood gas exchange appearing after surgery. PRF leads to longer hospital stays and higher mortality. The time frame for recognizing when respiratory failure is related to the surgical-anesthetic insult remains imprecise, however, and researchers have used different clinical events instead of blood gas measures to define the outcome. Still, studies in specific surgical populations or large patient samples have identified a range of predictors of PRF risk: type of surgery and comorbidity, mechanical ventilation, and multiple hits to the lung have been found to be relevant in most of these studies. Recently, risk-scoring systems for PRF have been developed and are being applied in new controlled trials of PRF-risk reduction measures. Current evidence favors carefully managing intraoperative ventilator use and fluids, reducing surgical aggression, and preventing wound infection and pain. PRF is a life-threatening event that is challenging for the surgical team. Risk prediction scales based on large population studies are being developed and validated. We need high-quality trials of preventive measures, particularly those related to ventilator use in both high risk and general populations.

  2. Association between the rapid shallow breathing index and extubation success in patients with traumatic brain injury

    PubMed Central

    dos Reis, Helena França Correia; Almeida, Mônica Lajana Oliveira; da Silva, Mário Ferreira; Moreira, Julião Oliveira; Rocha, Mário de Seixas

    2013-01-01

    Objective To investigate the association between the rapid shallow breathing index and successful extubation in patients with traumatic brain injury. Methods This study was a prospective study conducted in patients with traumatic brain injury of both genders who underwent mechanical ventilation for at least two days and who passed a spontaneous breathing trial. The minute volume and respiratory rate were measured using a ventilometer, and the data were used to calculate the rapid shallow breathing index (respiratory rate/tidal volume). The dependent variable was the extubation outcome: reintubation after up to 48 hours (extubation failure) or not (extubation success). The independent variable was the rapid shallow breathing index measured after a successful spontaneous breathing trial. Results The sample comprised 119 individuals, including 111 (93.3%) males. The average age of the sample was 35.0±12.9 years old. The average duration of mechanical ventilation was 8.1±3.6 days. A total of 104 (87.4%) participants achieved successful extubation. No association was found between the rapid shallow breathing index and extubation success. Conclusion The rapid shallow breathing index was not associated with successful extubation in patients with traumatic brain injury. PMID:24213084

  3. Factors Influencing Progressive Failure Analysis Predictions for Laminated Composite Structure

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.

    2008-01-01

    Progressive failure material modeling methods used for structural analysis including failure initiation and material degradation are presented. Different failure initiation criteria and material degradation models are described that define progressive failure formulations. These progressive failure formulations are implemented in a user-defined material model for use with a nonlinear finite element analysis tool. The failure initiation criteria include the maximum stress criteria, maximum strain criteria, the Tsai-Wu failure polynomial, and the Hashin criteria. The material degradation model is based on the ply-discounting approach where the local material constitutive coefficients are degraded. Applications and extensions of the progressive failure analysis material model address two-dimensional plate and shell finite elements and three-dimensional solid finite elements. Implementation details are described in the present paper. Parametric studies for laminated composite structures are discussed to illustrate the features of the progressive failure modeling methods that have been implemented and to demonstrate their influence on progressive failure analysis predictions.

  4. Predicting Failure Progression and Failure Loads in Composite Open-Hole Tension Coupons

    NASA Technical Reports Server (NTRS)

    Arunkumar, Satyanarayana; Przekop, Adam

    2010-01-01

    Failure types and failure loads in carbon-epoxy [45n/90n/-45n/0n]ms laminate coupons with central circular holes subjected to tensile load are simulated using progressive failure analysis (PFA) methodology. The progressive failure methodology is implemented using VUMAT subroutine within the ABAQUS(TradeMark)/Explicit nonlinear finite element code. The degradation model adopted in the present PFA methodology uses an instantaneous complete stress reduction (COSTR) approach to simulate damage at a material point when failure occurs. In-plane modeling parameters such as element size and shape are held constant in the finite element models, irrespective of laminate thickness and hole size, to predict failure loads and failure progression. Comparison to published test data indicates that this methodology accurately simulates brittle, pull-out and delamination failure types. The sensitivity of the failure progression and the failure load to analytical loading rates and solvers precision is demonstrated.

  5. Failure strength prediction for adhesively bonded single lap joints

    NASA Astrophysics Data System (ADS)

    Rahman, Niat Mahmud

    For adhesively bonded joint, failure strength depends on many factors such as material properties (both adhesive and adherend), specimen geometries, test environments, surface preparation procedures, etc. Failure occurs inside constitutive materials or along joint interfaces. Based on location, adhesively bonded failure mode can be classified as adhesive failure mode, cohesive failure mode and adherend failure mode. Failure mode directly affects the failure strength of joint. For last eight decades, researchers have developed analytical, empirical or semi-empirical methods capable of predicting failure strength for adhesively bonded joints generating either cohesive failure or adherend failure. Applicability of most of the methods is limited to particular cases. In this research, different failure modes for single lap joints (SLJs) were generated experimentally using epoxy based paste adhesive. Based on experimental data and analytical study, simplified failure prediction methods were developed for each failure mode. For adhesive failure mode, it is observed that peel stress distributions concur along interface near crack initiation points. All SLJs for this test endured consistent surface treatments. Geometric parameters of the joints were varied to study their effect on failure strength. Peel stress distributions were calculated using finite analysis (FEA). Based on peel stress distribution near crack initiation point, a failure model is proposed. Numerous analytical, empirical and semi-empirical models are available for predicting failure strengths of SLJs generating cohesive failures. However, most of the methods in the literature failed to capture failure behavior of SLJs having thickness of adhesive layer as variable. Cohesive failure mode was generated experimentally using aluminum as adherend and epoxy adhesive considering thickness of adhesive layers as variable within SLJs. Comparative study was performed among various methods. It was observed that

  6. A method to predict electromigration failure of metal lines

    NASA Astrophysics Data System (ADS)

    Sasagawa, Kazuhiko; Naito, Kazushi; Saka, Masumi; Abé, Hiroyuki

    1999-12-01

    A new calculation method of atomic flux divergence (AFDgen) due to electromigration has recently been proposed by considering all the factors on void formation, and AFDgen has been identified as a parameter governing void formation by observing agreement of the numerical prediction of the void with experiment. In this article, a method to predict the electromigration failure of metal lines was proposed by using AFDgen. Lifetime and failure site in a polycrystalline line were predicted by numerical simulation of the processes of void initiation, its growth to line failure, where the change in distributions of current density and temperature with void growth was taken into account. The usefulness of this prediction method was verified by the experiment where the angled aluminum line was treated. The failure location was determined by the line shape and the operating condition. The present simulation accurately predicted the lifetime as well as the failure location of the metal line.

  7. Predicting Computer System Failures Using Support Vector Machines

    SciTech Connect

    Fulp, Errin W.; Fink, Glenn A.; Haack, Jereme N.

    2008-12-07

    Mitigating the impact of computer failure is possible if accurate failure predictions are provided. Resources, applications, and services can be scheduled around predicted failure and limit the impact. Such strategies are especially important for multi-computer systems, such as compute clusters, that experience a higher rate failure due to the large number of components. However providing accurate predictions with sufficient lead time remains a challenging problem. This paper describes a new spectrum-kernel Support Vector Machine (SVM) approach to predict failure events based on system log files. These files contain messages that represent a change of system state. While a single message in the file may not be sufficient for predicting failure, a sequence or pattern of messages may be. The approach described in this paper will use a sliding window (sub-sequence) of messages to predict the likelihood of failure. The frequency representation of the message sub-sequences observed are then used as input to the SVM that associates the messages to a class of failed or non-failed system. Experimental results using actual system log files from a Linux-based compute cluster indicate the proposed SVM approach can predict hard disk failure with an accuracy of 76% one day in advance.

  8. PET(CO2) measurement and feature extraction of capnogram signals for extubation outcomes from mechanical ventilation.

    PubMed

    Rasera, Carmen C; Gewehr, Pedro M; Domingues, Adriana Maria T

    2015-02-01

    Capnography is a continuous and noninvasive method for carbon dioxide (CO2) measurement, and it has become the standard of care for basic respiratory monitoring for intubated patients in the intensive care unit. In addition, it has been used to adjust ventilatory parameters during mechanical ventilation (MV). However, a substantial debate remains as to whether capnography is useful during the process of weaning and extubation from MV during the postoperative period. Thus, the main objective of this study was to present a new use for time-based capnography data by measuring the end-tidal CO2 pressure ([Formula: see text]), partial pressure of arterial CO2 ([Formula: see text]) and feature extraction of capnogram signals before extubation from MV to evaluate the capnography as a predictor of outcome extubation in infants after cardiac surgery. Altogether, 82 measurements were analysed, 71.9% patients were successfully extubated, and 28.1% met the criteria for extubation failure within 48 h. The ROC-AUC analysis for quantitative measure of the capnogram showed significant differences (p < 0.001) for: expiratory time (0.873), slope of phase III (0.866), slope ratio (0.923) and ascending angle (0.897). In addition, the analysis of [Formula: see text] (0.895) and [Formula: see text] (0.924) obtained 30 min before extubation showed significant differences between groups. The [Formula: see text] mean value for success and failure extubation group was 39.04 mmHg and 46.27 mmHg, respectively. It was also observed that high CO2 values in patients who had returned MV was 82.8  ±  21 mmHg at the time of extubation failure. Thus, [Formula: see text] measurements and analysis of features extracted from a capnogram can differentiate extubation outcomes in infant patients under MV, thereby reducing the physiologic instability caused by failure in this process.

  9. Predictability of steel containment response near failure

    SciTech Connect

    Costello, J.F.; Ludwigsen, J.S.; Luk, V.K.; Hessheimer, M.F.

    2000-01-06

    The Nuclear Power Engineering Corporation of Japan and the US Nuclear Regulatory Commission Office of Nuclear Regulatory Research, are co-sponsoring and jointly funding a Cooperative Containment Research Program at Sandia National Laboratories, Albuquerque, New Mexico, USA. As a part of this program, a steel containment vessel model and contact structure assembly was tested to failure with over pressurization at Sandia on December 11--12, 1996. The steel containment vessel model was a mixed-scale model (1:10 in geometry and 1:4 in shell thickness) of a steel containment for an improved Mark-II Boiling Water Reactor plant in Japan. The contact structure, which is a thick, bell-shaped steel shell separated at a nominally uniform distance from the model, provides a simplified representation of features of the concrete reactor shield building in the actual plant. The objective of the internal pressurization test was to provide measurement data of the structural response of the model up to its failure in order to validate analytical modeling, to find its pressure capacity, and to observe the failure model and mechanisms.

  10. Computational Methods for Failure Analysis and Life Prediction

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K. (Compiler); Harris, Charles E. (Compiler); Housner, Jerrold M. (Compiler); Hopkins, Dale A. (Compiler)

    1993-01-01

    This conference publication contains the presentations and discussions from the joint UVA/NASA Workshop on Computational Methods for Failure Analysis and Life Prediction held at NASA Langley Research Center 14-15 Oct. 1992. The presentations focused on damage failure and life predictions of polymer-matrix composite structures. They covered some of the research activities at NASA Langley, NASA Lewis, Southwest Research Institute, industry, and universities. Both airframes and propulsion systems were considered.

  11. Prediction of Technological Failures in Nuclear Power Plant Operation

    SciTech Connect

    Salnykov, A. A.

    2015-01-15

    A method for predicting operating technological failures in nuclear power plants which makes it possible to reduce the unloading of the generator unit during the onset and development of an anomalous engineering state of the equipment by detecting a change in state earlier and taking suitable measures. With the circulating water supply loop of a nuclear power plant as an example, scenarios and algorithms for predicting technological failures in the operation of equipment long before their actual occurrence are discussed.

  12. Ultra fast-track extubation in heart transplant surgery patients.

    PubMed

    Kianfar, Amir Abbas; Ahmadi, Zargham Hossein; Mirhossein, Seyed Mohsen; Jamaati, Hamidreza; Kashani, Babak Sharif; Mohajerani, Seyed Amir; Firoozi, Ehsan; Salehi, Farshid; Radmand, Golnar; Hashemian, Seyed Mohammadreza

    2015-01-01

    Heart transplant surgeries using cardiopulmonary bypass (CPB) typically requires mechanical ventilation in intensive care units (ICU) in post-operation period. Ultra fast-track extubation (UFE) have been described in patients undergoing various cardiac surgeries. To determine the possibility of ultra-fast-track extubation instead of late extubation in post heart transplant patients. Patients randomly assigned into two groups; Ultra fast-track extubation (UFE) group was defined by extubation inside operating room right after surgery. Late extubation group was defined by patients who were not extubated in operating room and transferred to post operation cardiac care unit (CCU) to extubate. The mean cardiopulmonary bypass time was 136.8 ± 25.7 minutes in ultra-fast extubation and 145.3 ± 29.8 minutes in late extubation patients (P > 0.05). Mechanical ventilation duration (days) was 0 days in ultra-fast and 2.31 ± 1.8 days in late extubation. Length of ICU stay was significantly higher in late extubation group (4.2 ± 1.2 days) than the UFE group (1.72 ± 1.5 days) (P = 0.02). In survival analysis there was no significant difference between ultra-fast and late extubation groups (Log-rank test, P = 0.9). Patients undergoing cardiac transplant could be managed with "ultra-fast-track extubation", without increased morbidity and mortality.

  13. Ultrasonographic diaphragmatic excursion is inaccurate and not better than the MRC score for predicting weaning-failure in mechanically ventilated patients.

    PubMed

    Carrie, Cédric; Gisbert-Mora, Chloé; Bonnardel, Eline; Gauche, Bernard; Biais, Matthieu; Vargas, Frédéric; Hilbert, Gilles

    2017-02-01

    To assess the ability of diaphragmatic ultrasound (US) to predict weaning failure in mechanically ventilated patients undergoing a first spontaneous breathing trial (SBT). During a 4-month period, 67 consecutive patients eligible for a first SBT underwent US measurements of maximal diaphragmatic excursion (MDE) by a right anterior subcostal approach. Weaning failure was defined as either the failure of SBT or the need for resumption of ventilatory support for acute respiratory failure or death within 48h following successful extubation. The accuracy of diaphragmatic ultrasound and the Medical Research Council (MRC) score when predicting weaning failure was assessed via a receiver operating curve analysis. The feasibility rate for the ultrasound measurements was 63%. Mean values of MDE were significantly higher in patients who succeeded at their first weaning attempt (4.1±2.1 versus 3±1.8cm, P=0.04). Using a threshold of MDE≤2.7cm, the sensitivity and specificity of diaphragmatic ultrasound in predicting weaning failure were 59% [39-77%] and 71% [57-82%] with an AUC at 0.65 [0.51-0.78]. There was no significant difference between MDE values and MRC scores for predicting weaning failure (P=0.73). A decrease in MDE values may be associated with an unfavourable weaning outcome. Diaphragmatic excursion measured by ultrasound is however unable by itself to predict weaning failure at the bedside of patients undergoing a first spontaneous breathing trial and does not provide any additional value compared to the MRC score. Copyright © 2016. Published by Elsevier Masson SAS.

  14. Two-parameter Failure Model Improves Time-independent and Time-dependent Failure Predictions

    SciTech Connect

    Huddleston, R L

    2004-01-27

    A new analytical model for predicting failure under a generalized, triaxial stress state was developed by the author and initially reported in 1984. The model was validated for predicting failure under elevated-temperature creep-rupture conditions. Biaxial data for three alloy steels, Types 304 and 316 stainless steels and Inconel 600, demonstrated two to three orders of magnitude reduction in the scatter of predicted versus observed creep-rupture times as compared to the classical failure models of Mises, Tresca, and Rankine. In 1990, the new model was incorporated into American Society of Mechanical Engineers (ASME) Code Case N47-29 for design of components operating under creep-rupture conditions. The current report provides additional validation of the model for predicting failure under time-independent conditions and also outlines a methodology for predicting failure under cyclic, time-dependent, creep-fatigue conditions. The later extension of the methodology may have the potential to improve failure predictions there as well. These results are relevant to most design applications, but they have special relevance to high-performance design applications such as components for high-pressure equipment, nuclear reactors, and jet engines.

  15. Review on failure prediction techniques of composite single lap joint

    SciTech Connect

    Ab Ghani, A.F. Rivai, Ahmad

    2016-03-29

    Adhesive bonding is the most appropriate joining method in construction of composite structures. The use of reliable design and prediction technique will produce better performance of bonded joints. Several papers from recent papers and journals have been reviewed and synthesized to understand the current state of the art in this area. It is done by studying the most relevant analytical solutions for composite adherends with start of reviewing the most fundamental ones involving beam/plate theory. It is then extended to review single lap joint non linearity and failure prediction and finally on the failure prediction on composite single lap joint. The review also encompasses the finite element modelling part as tool to predict the elastic response of composite single lap joint and failure prediction numerically.

  16. Postinjury immune monitoring: can multiple organ failure be predicted?

    PubMed

    Visser, Tjaakje; Pillay, Janesh; Koenderman, Leo; Leenen, Luke P H

    2008-12-01

    Multiple organ failure is the main cause of late morbidity and mortality after severe injury. This disease state is driven by a dysfunctional immune system. Prediction of multiple organ failure on the basis of clinical parameters appears to be insufficient. A better understanding of immunological pathogenesis underlying multiple organ failure may lead to better prediction and innovation in treatment strategy in order to increase the survival of trauma patients. Immune monitoring has increased the knowledge of the pathogenesis of multiple organ failure, but many mechanisms underlying its cause and development remain to be elucidated. Consequently, adequate predictive markers for diagnosis and monitoring still need to be developed. General markers of inflammation including cytokines are correlated with posttraumatic complications with a low sensitivity and specificity and are, therefore, of little use as prognostic markers. Current findings regarding the functionality of immune cells are promising and might be of prognostic value in the near future.

  17. Predicting Failure Under Laboratory Conditions: Learning the Physics of Slow Frictional Slip and Dynamic Failure

    NASA Astrophysics Data System (ADS)

    Rouet-Leduc, B.; Hulbert, C.; Riviere, J.; Lubbers, N.; Barros, K.; Marone, C.; Johnson, P. A.

    2016-12-01

    Forecasting failure is a primary goal in diverse domains that include earthquake physics, materials science, nondestructive evaluation of materials and other engineering applications. Due to the highly complex physics of material failure and limitations on gathering data in the failure nucleation zone, this goal has often appeared out of reach; however, recent advances in instrumentation sensitivity, instrument density and data analysis show promise toward forecasting failure times. Here, we show that we can predict frictional failure times of both slow and fast stick slip failure events in the laboratory. This advance is made possible by applying a machine learning approach known as Random Forests1(RF) to the continuous acoustic emission (AE) time series recorded by detectors located on the fault blocks. The RF is trained using a large number of statistical features derived from the AE time series signal. The model is then applied to data not previously analyzed. Remarkably, we find that the RF method predicts upcoming failure time far in advance of a stick slip event, based only on a short time window of data. Further, the algorithm accurately predicts the time of the beginning and end of the next slip event. The predicted time improves as failure is approached, as other data features add to prediction. Our results show robust predictions of slow and dynamic failure based on acoustic emissions from the fault zone throughout the laboratory seismic cycle. The predictions are based on previously unidentified tremor-like acoustic signals that occur during stress build up and the onset of macroscopic frictional weakening. We suggest that the tremor-like signals carry information about fault zone processes and allow precise predictions of failure at any time in the slow slip or stick slip cycle2. If the laboratory experiments represent Earth frictional conditions, it could well be that signals are being missed that contain highly useful predictive information. 1Breiman

  18. Predicting Modes and Displacements of Seismic Rock Slope Failures

    NASA Astrophysics Data System (ADS)

    Gibson, M. D.; Wartman, J.; Keefer, D. K.; Maclaughlin, M.; Arnold, L.; Applegate, K. N.; Smith, S.; Adams, S.

    2013-12-01

    Seismically induced rock slope failures have resulted in billions of dollars of economic damage and enormous loss of life throughout the world. Accurate prediction of the triggering and run out of these failures is elusive for a variety of reasons, including knowledge of the physical modes of failure. Our research explores the potential failure modes of an idealized rigid rock block and expands the modes typically considered to include not only sliding but also toppling (pure forward rotation) and slumping (combined backward rotation and translation). The yield acceleration (or minimum inertial acceleration to cause block movement) for slumping, similar to toppling, is found to be lower than for pure translational sliding. These yield accelerations indicate the initial modes of rock block failure; however, they do not always predict the ultimate failure mode. To predict the final failure modes, the results of discrete element numerical analyses were compared to pseudo static yield acceleration to develop a seismic failure mode decision-making chart based on block geometry and interface friction. With regard to seismic displacement predictions, current simplified models predicting ultimate displacement of a mass under seismic conditions are limited to purely translating, sliding blocks (i.e. Newmark's sliding block method). Our modeling introduces additional simplified analyses to predict ultimate displacement in toppling and slumping modes as well. Important findings from these new methods are that the magnitude of seismically-induced displacement is dependent on the size of the block (or failure mass) and that as the yield acceleration decreases the seismically induced displacements increase. We plan to map these tools into analyses that evaluate rock slope systems with complex geology and geotechnical characteristics. It is envisioned that the decision chart, which predicts the initial and ultimate modes of failure based on block geometry and interface friction

  19. Product component genealogy modeling and field-failure prediction

    SciTech Connect

    King, Caleb; Hong, Yili; Meeker, William Q.

    2016-04-13

    Many industrial products consist of multiple components that are necessary for system operation. There is an abundance of literature on modeling the lifetime of such components through competing risks models. During the life-cycle of a product, it is common for there to be incremental design changes to improve reliability, to reduce costs, or due to changes in availability of certain part numbers. These changes can affect product reliability but are often ignored in system lifetime modeling. By incorporating this information about changes in part numbers over time (information that is readily available in most production databases), better accuracy can be achieved in predicting time to failure, thus yielding more accurate field-failure predictions. This paper presents methods for estimating parameters and predictions for this generational model and a comparison with existing methods through the use of simulation. Our results indicate that the generational model has important practical advantages and outperforms the existing methods in predicting field failures.

  20. Comparison of Proportional Assist Ventilation Plus, T-Tube Ventilation, and Pressure Support Ventilation as Spontaneous Breathing Trials for Extubation: A Randomized Study.

    PubMed

    Teixeira, Sandy Nogueira; Osaku, Erica Fernanda; Costa, Claudia Rejane Lima de Macedo; Toccolini, Beatriz Fernandes; Costa, Nicolle Lamberti; Cândia, Maria Fernanda; Leite, Marcela Aparecida; Jorge, Amaury Cezar; Duarte, Péricles Almeida Delfino

    2015-11-01

    Failure to wean can prolong ICU stay, increase complications associated with mechanical ventilation, and increase morbidity and mortality. The spontaneous breathing trial (SBT) is one method used to assess weaning. The aim of this study was to assess proportional assist ventilation plus (PAV+) as an SBT by comparing its applicability, safety, and efficacy with T-tube and pressure support ventilation (PSV). A randomized study was performed involving 160 adult subjects who remained on mechanical ventilation for > 24 h. Subjects were randomly assigned to the PAV+, PSV, or T-tube group. When subjects were ready to perform the SBT, subjects in the PAV+ group were ventilated in PAV+ mode (receiving support of up to 40%), the pressure support was reduced to 7 cm H2O in the PSV group, and subjects in the T-tube group were connected to one T-piece with supplemental oxygen. Subjects were observed for signs of intolerance, whereupon the trial was interrupted. When the trial succeeded, the subjects were extubated and assessed until discharge. The subjects were predominantly male (66.5%), and the leading cause of admission was traumatic brain injury. The groups were similar with respect to baseline characteristics, and no significant difference was observed among the groups regarding extubation success or failure. Analysis of the specificity and sensitivity revealed good sensitivity for all groups; however, the PAV+ group had higher specificity (66.6%) and higher sensitivity (97.6%), with prediction of ∼ 92.1% of the success and failure events. No significant differences in the groups was observed regarding the rate of extubation failure, duration of mechanical ventilation, and ICU and hospital stay, indicating that PAV+ is an alternative for use as an SBT. Copyright © 2015 by Daedalus Enterprises.

  1. Prediction failure of a wolf landscape model

    USGS Publications Warehouse

    Mech, L.D.

    2006-01-01

    I compared 101 wolf (Canis lupus) pack territories formed in Wisconsin during 1993-2004 to the logistic regression predictive model of Mladenoff et al. (1995, 1997, 1999). Of these, 60% were located in putative habitat suitabilities 50% remained unoccupied by known packs after 24 years of recolonization. This model was a poor predictor of wolf re-colonizing locations in Wisconsin, apparently because it failed to consider the adaptability of wolves. Such models should be used cautiously in wolf-management or restoration plans.

  2. Factors affecting the decision to defer endotracheal extubation after surgery for congenital heart disease: a prospective observational study.

    PubMed

    Kin, Nobuhide; Weismann, Constance; Srivastava, Shubhika; Chakravarti, Sujata; Bodian, Carol; Hossain, Sabera; Krol, Marina; Hollinger, Ingrid; Nguyen, Khanh; Mittnacht, Alexander J C

    2011-08-01

    Fast-tracking and early endotracheal extubation have been described in patients undergoing surgery for congenital heart disease (CHD); however, criteria for patient selection have not been validated in a prospective manner. Our goal in this study was to prospectively identify factors associated with the decision to defer endotracheal extubation in the operating room (OR). We performed a prospective observational study of 275 patients (median age 18 months) at the Mount Sinai Medical Center (MSMC), New York, New York, and 49 patients (median age 25 months) at the University of Tokyo Hospital (UTH), Tokyo, Japan, undergoing surgery for CHD requiring cardiopulmonary bypass. These patients were all eligible for fast-tracking, including extubation in the OR immediately after surgery, according to the respective inclusion/exclusion criteria applied at the 2 sites. Eighty-nine percent of patients at the MSMC, and 65% of patients at the UTH were extubated in the OR. At the MSMC, all patients without aortic cross-clamp, and patients with simple procedures (Risk Adjustment for Congenital Heart Surgery [RACHS] score 1) were extubated in the OR. Among the remaining MSMC patients, regression analysis showed that procedure complexity was still an independent predictor for not proceeding with planned extubation in the OR. Extubation was more likely to be deferred in the RACHS score 3 surgical risk patients compared with the RACHS score 2 group (P = 0.005, odds ratio 3.8 [CI: 1.5, 9.7]). Additionally, trisomy 21 (P = 0.0003, odds ratio 9.9 [CI: 2.9, 34.5]) and age (P = 0.0015) were significant independent predictors for deferring OR extubation. We tested our findings on the patients from the UTH by developing risk categories from the MSMC data that ranked eligible patients according to the chance of OR extubation. The risk categories proved to predict endotracheal extubation in the 49 patients who had undergone surgery at the UTH relative to their overall extubation rate, despite

  3. Reflex cough PEF as a predictor of successful extubation in neurological patients*

    PubMed Central

    Kutchak, Fernanda Machado; Debesaitys, Andressa Maciel; Rieder, Marcelo de Mello; Meneguzzi, Carla; Skueresky, Amanda Soares; Alberto, Luiz; Bianchin, Marino Muxfeldt

    2015-01-01

    Abstract Objective: To evaluate the use of reflex cough PEF as a predictor of successful extubation in neurological patients who were candidates for weaning from mechanical ventilation. Methods: This was a cross-sectional study of 135 patients receiving mechanical ventilation for more than 24 h in the ICU of Cristo Redentor Hospital, in the city of Porto Alegre, Brazil. Reflex cough PEF, the rapid shallow breathing index, MIP, and MEP were measured, as were ventilatory, hemodynamic, and clinical parameters. Results: The mean age of the patients was 47.8 ± 17 years. The extubation failure rate was 33.3%. A reflex cough PEF of < 80 L/min showed a relative risk of 3.6 (95% CI: 2.0-6.7), and the final Glasgow Coma Scale score showed a relative risk of 0.64 (95% CI: 0.51-0.83). For every 1-point increase in a Glasgow Coma Scale score of 8, there was a 36% reduction in the risk of extubation failure. Conclusions: Reflex cough PEF and the Glasgow Coma Scale score are independent predictors of extubation failure in neurological patients admitted to the ICU. PMID:26398756

  4. Interventions to Improve Rates of Successful Extubation in Preterm Infants: A Systematic Review and Meta-analysis.

    PubMed

    Ferguson, Kristin N; Roberts, Calum T; Manley, Brett J; Davis, Peter G

    2017-02-01

    Clinicians aim to extubate preterm infants as early as possible, to minimize the risks of mechanical ventilation. Extubation is often unsuccessful owing to lung disease or inadequate respiratory drive. To conduct a systematic review and meta-analysis of interventions to improve rates of successful extubation in preterm infants. Searches were undertaken in PubMed and The Cochrane Library. The review was conducted using the methods of the Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were included if they were randomized clinical trials published in English, enrolled intubated preterm infants (born <37 weeks' gestation), and reported 1 or both of the primary outcomes. One thousand three hundred seventy-nine titles were screened independently by 2 investigators to assess need for full-text review. Disagreements were resolved via consensus of all authors. Where no Cochrane Review existed for an intervention, or not all identified studies were included, a new pooled analysis was performed. Primary outcomes were treatment failure or reintubation within 7 days of extubation. Fifty studies were eligible for inclusion. Continuous positive airway pressure reduced extubation failure in comparison with head-box oxygen (risk ratio [RR], 0.59; 95% CI, 0.48-0.72; number needed to treat [NNT], 6; 95% CI, 3-9). Nasal intermittent positive pressure ventilation was superior to continuous positive airway pressure in preventing extubation failure (RR, 0.70; 95% CI, 0.60-0.81; NNT, 8; 95% CI, 5-13). High-flow nasal cannula therapy and continuous positive airway pressure had similar efficacy (RR, 1.11; 95% CI, 0.84-1.47). Methylxanthines reduced extubation failure (RR, 0.48; 95% CI, 0.32-0.71; NNT, 4; 95% CI, 2-7) compared with placebo or no treatment. Corticosteroids (RR, 0.18; 95% CI, 0.04-0.97; NNT, 12; 95% CI, 6-100) and chest physiotherapy (RR, 0.32; 95% CI, 0.13-0.82; NNT, 15; 95% CI, 7-50) both reduced extubation

  5. Extubation force: tape versus endotracheal tube holders.

    PubMed

    Carlson, Jestin; Mayrose, James; Krause, Richard; Jehle, Dietrich

    2007-12-01

    Tape is the standard method for securing endotracheal tubes to prevent extubation. This study examines the force required to extubate endotracheal tubes from cadavers with either tape or one of 4 commercially available endotracheal tube holders. Newly deceased, unembalmed cadavers were intubated with standard tracheal intubation techniques. The endotracheal tube was secured with either tape or one of 4 commercially available endotracheal tube holders. The endotracheal tube was then connected to a force-measuring device and pulled until the cuff was removed from the trachea. The largest force recorded on the device was then marked as the "extubation force" for that trial. When tape was used to secure the endotracheal tube, it required a significantly larger force to extubate than 3 of 4 off-the-shelf endotracheal tube holders. Only the Thomas Tube Holder secured the endotracheal tube better than tape. Although the Thomas Tube Holder had the greatest holding force in this study, tape was shown to be the least expensive and outperformed 3 other commercially available devices used to secure endotracheal tubes.

  6. Successful Extubation Using Heliox BiPAP in Two Patients with Postextubation Stridor

    PubMed Central

    Punj, Pragya; Nattanmai, Premkumar; George, Pravin

    2017-01-01

    Postextubation stridor is associated with significant morbidity. It commonly results in extubation failure after established medical treatment fails, such as nebulized epinephrine and/or intravenous steroids. The role of heliox (i.e., combination of helium and oxygen) in managing patients with postextubation stridor has not been fully established. We report two cases of postextubation stridor successfully treated with heliox delivered with bilevel positive airway pressure (BiPAP) after failure of standard medical therapy. PMID:28373921

  7. Saturated fat intake predicts biochemical failure after prostatectomy.

    PubMed

    Strom, Sara S; Yamamura, Yuko; Forman, Michele R; Pettaway, Curtis A; Barrera, Stephanie L; DiGiovanni, John

    2008-06-01

    Previous reports show that obesity predicts biochemical failure after treatment for localized prostate cancer. Since obesity is associated with increased fat consumption, we investigated the role that dietary fat intake plays in modulating obesity-related risk of biochemical failure. We evaluated the association between saturated fat intake and biochemical failure among 390 men from a previously described prostatectomy cohort. Participants completed a food frequency questionnaire collecting nutrient information for the year prior to diagnosis. Because fat and energy intake are highly correlated, the residual method was used to adjust fat (total and saturated) intakes for energy. Biochemical-failure-free-survival rates were calculated using the Kaplan-Meier method. Crude and adjusted effects were estimated using Cox proportional hazards models. During a mean follow-up of 70.6 months, 78 men experienced biochemical failure. Men who consumed high- saturated fat (HSF) diets were more likely to experience biochemical failure (p = 0.006) and had significantly shorter biochemical-failure-free-survival than men with low saturated fat (LSF) diets (26.6 vs. 44.7 months, respectively, p = 0.002). After adjusting for obesity and clinical variables, HSF-diet patients were almost twice as likely to experience biochemical failure (hazard ratio = 1.95, p = 0.008) compared to LSF diet patients. Men who were both obese and consumed HSF diets had the shortest biochemical-failure-free-survival (19 months), and nonobese men who consumed LSF diets had the longest biochemical-failure-free-survival (46 months, p < 0.001). Understanding the interplay between modifiable factors, such as diet and obesity, and disease characteristics may lead to the development of behavioral and/or targeted interventions for patients at increased risk of progression. (c) 2008 Wiley-Liss, Inc.

  8. Failure probability prediction of dielectric ceramics in multilayer capacitors

    SciTech Connect

    Wereszczak, A.A.; Breder, K.; Ferber, M.K.; Bridge, R.J.; Riester, L.; Kirkland, T.P.

    1998-11-01

    Dielectric ceramics in multilayer capacitors are subjected to manufacturing or service thermomechanical stresses which, if severe enough, will cause mechanical failure and perhaps subsequent loss of electrical function. Strength of monolithic ceramics is probabilistic in nature; however, probabilistic design of such electronic ceramic components generally has not been used by manufacturers and end-users of these components. To illustrate how probabilistic design may be utilized for small components, the present study demonstrates the applicability of an existing probabilistic life design computer code in the prediction of failure probability of a dielectric ceramic in an arbitrary multilayer capacitor. Issues involving the generation of representative strength and fatigue data for specimens at this small scale and the ultimate failure probability prediction of dielectric ceramics in multilayer capacitors are presented. Additionally, alternative means to generate a strength distribution as input for the probabilistic life design computer codes which are under consideration by the authors are discussed.

  9. Model-Biased, Data-Driven Adaptive Failure Prediction

    NASA Technical Reports Server (NTRS)

    Leen, Todd K.

    2004-01-01

    This final report, which contains a research summary and a viewgraph presentation, addresses clustering and data simulation techniques for failure prediction. The researchers applied their techniques to both helicopter gearbox anomaly detection and segmentation of Earth Observing System (EOS) satellite imagery.

  10. Application of Weibull Criterion to failure prediction in compsites

    SciTech Connect

    Cain, W. D.; Knight, Jr., C. E.

    1981-04-20

    Fiber-reinforced composite materials are being widely used in engineered structures. This report examines how the general form of the Weibull Criterion, including the evaluation of the parameters and the scaling of the parameter values, can be used for the prediction of component failure.

  11. Fracture mechanics parameters for failure prediction of composite resins.

    PubMed

    De Groot, R; Van Elst, H C; Peters, M C

    1988-06-01

    This study contains the first part of a research project in which the applicability of fracture mechanics parameters to predict failure of a restored tooth was investigated. Fracture mechanics parameters have been used in dental research before, but were restricted to comparative studies between various brands of composites. The critical values of the opening mode stress intensity factor (KI), its equivalents, the strain energy release rate (GI), and the J integral (JI), were measured with single-edge notched-bend (SENB) specimens of dental composite in a three-point bend test. The measured values of KIc for Silux (KIc = 0.99 +/- 0.03 MNm-3/2) and P-30 (KIc = 1.88 +/- 0.12 MNm-3/2), compared with values from the literature, show quantitative agreement. The J integral was computed by means of finite element analysis (FEA) on a two-dimensional model of the SENB specimens. The critical value of the J integral (measured with SENB specimens, notch depth-to-width ratio (a/W) = 1/2) was used to predict failure of specimens having an arbitrary geometry. In this study, failure was predicted for SENB specimens with notch depth-to-width ratio (a/W) = 1/4 and 3/4. The predicted deflection and load at failure correspond well with the measured deflection and load.

  12. Failure prediction of thin beryllium sheets used in spacecraft structures

    NASA Technical Reports Server (NTRS)

    Roschke, Paul N.; Mascorro, Edward; Papados, Photios; Serna, Oscar R.

    1991-01-01

    The primary objective of this study is to develop a method for prediction of failure of thin beryllium sheets that undergo complex states of stress. Major components of the research include experimental evaluation of strength parameters for cross-rolled beryllium sheet, application of the Tsai-Wu failure criterion to plate bending problems, development of a high order failure criterion, application of the new criterion to a variety of structures, and incorporation of both failure criteria into a finite element code. A Tsai-Wu failure model for SR-200 sheet material is developed from available tensile data, experiments carried out by NASA on two circular plates, and compression and off-axis experiments performed in this study. The failure surface obtained from the resulting criterion forms an ellipsoid. By supplementing experimental data used in the the two-dimensional criterion and modifying previously suggested failure criteria, a multi-dimensional failure surface is proposed for thin beryllium structures. The new criterion for orthotropic material is represented by a failure surface in six-dimensional stress space. In order to determine coefficients of the governing equation, a number of uniaxial, biaxial, and triaxial experiments are required. Details of these experiments and a complementary ultrasonic investigation are described in detail. Finally, validity of the criterion and newly determined mechanical properties is established through experiments on structures composed of SR200 sheet material. These experiments include a plate-plug arrangement under a complex state of stress and a series of plates with an out-of-plane central point load. Both criteria have been incorporated into a general purpose finite element analysis code. Numerical simulation incrementally applied loads to a structural component that is being designed and checks each nodal point in the model for exceedance of a failure criterion. If stresses at all locations do not exceed the failure

  13. Failure prediction of thin beryllium sheets used in spacecraft structures

    NASA Astrophysics Data System (ADS)

    Roschke, Paul N.; Mascorro, Edward; Papados, Photios; Serna, Oscar R.

    1991-12-01

    The primary objective of this study is to develop a method for prediction of failure of thin beryllium sheets that undergo complex states of stress. Major components of the research include experimental evaluation of strength parameters for cross-rolled beryllium sheet, application of the Tsai-Wu failure criterion to plate bending problems, development of a high order failure criterion, application of the new criterion to a variety of structures, and incorporation of both failure criteria into a finite element code. A Tsai-Wu failure model for SR-200 sheet material is developed from available tensile data, experiments carried out by NASA on two circular plates, and compression and off-axis experiments performed in this study. The failure surface obtained from the resulting criterion forms an ellipsoid. By supplementing experimental data used in the the two-dimensional criterion and modifying previously suggested failure criteria, a multi-dimensional failure surface is proposed for thin beryllium structures. The new criterion for orthotropic material is represented by a failure surface in six-dimensional stress space. In order to determine coefficients of the governing equation, a number of uniaxial, biaxial, and triaxial experiments are required. Details of these experiments and a complementary ultrasonic investigation are described in detail. Finally, validity of the criterion and newly determined mechanical properties is established through experiments on structures composed of SR200 sheet material. These experiments include a plate-plug arrangement under a complex state of stress and a series of plates with an out-of-plane central point load. Both criteria have been incorporated into a general purpose finite element analysis code. Numerical simulation incrementally applied loads to a structural component that is being designed and checks each nodal point in the model for exceedance of a failure criterion. If stresses at all locations do not exceed the failure

  14. Predicting the failure load of the distal radius.

    PubMed

    Muller, Monique E; Webber, Colin E; Bouxsein, Mary L

    2003-06-01

    The distal radius is an important site for the early detection of patients at risk for fracture. Since measuring bone strength in vivo is not possible, we evaluated which bone assessment method of the forearm would best predict failure load of the distal radius and computed a factor of risk for wrist fracture (Phi wrist). Thirty-eight cadaveric forearm specimens were measured by five different techniques to assess bone density, bone mineral content, geometry and trabecular structure at the distal forearm. The bone assessment techniques included dual-energy X-ray absorptiometry (DXA) of the radius, peripheral quantitative computed tomography (pQCT) of the 4% and 20% distal sites of the radius, DXA of the phalanges, digital X-ray radiogrammetry of the forearm (DXR-BMD), and quantitative ultrasound of the radius. The failure load of each excised radius was determined by simulating a fall on an outstretched hand. The pQCT measurements of polar stress-strain index and cortical content explained the greatest portion of variance in failure load (r2=0.82-0.85). Bone mineral content measures were generally better predictors of failure load (r2=0.53-0.85) than the corresponding volumetric or areal bone mineral density values (r2=0.22-0.69) measured by either pQCT or DXA. Multiple regression analysis showed that the addition of a bone geometry measure improved the ability of a bone density measure alone to predict failure load. There was high variability in the ability of different techniques and different variables within a given technique to predict failure load. Estimates of the factor of risk for wrist fracture (Phi wrist) revealed that the women in this study would have been likely to fracture their distal radius upon falling from a standing height (Phi wrist= 1.04), whereas the men would have likely withstood the impact without fracturing their wrist (Phi wrist= 0.79).

  15. Failure prediction of thin beryllium sheets used in spacecraft structures

    NASA Technical Reports Server (NTRS)

    Roschke, Paul N.; Papados, Photios; Mascorro, Edward

    1991-01-01

    In an attempt to predict failure for cross-rolled beryllium sheet structures, high order macroscopic failure criteria are used. These require the knowledge of in-plane uniaxial and shear strengths. Test results are included for in-plane biaxial tension, uniaxial compression for two different material orientations, and shear. All beryllium specimens have the same chemical composition. In addition, all experimental work was performed in a controlled laboratory environment. Numerical simulation complements these tests. A brief bibliography supplements references listed in a previous report.

  16. Empirical sediment transport function predicting seepage erosion undercutting for cohesive bank failure prediction

    USDA-ARS?s Scientific Manuscript database

    Seepage erosion is an important factor in hillslope instability and failure. However, predicting erosion by subsurface flow or seepage and incorporating its effects into stability models remains a challenge. Limitations exist with all existing seepage erosion sediment transport functions, including ...

  17. Product component genealogy modeling and field-failure prediction

    DOE PAGES

    King, Caleb; Hong, Yili; Meeker, William Q.

    2016-04-13

    Many industrial products consist of multiple components that are necessary for system operation. There is an abundance of literature on modeling the lifetime of such components through competing risks models. During the life-cycle of a product, it is common for there to be incremental design changes to improve reliability, to reduce costs, or due to changes in availability of certain part numbers. These changes can affect product reliability but are often ignored in system lifetime modeling. By incorporating this information about changes in part numbers over time (information that is readily available in most production databases), better accuracy can bemore » achieved in predicting time to failure, thus yielding more accurate field-failure predictions. This paper presents methods for estimating parameters and predictions for this generational model and a comparison with existing methods through the use of simulation. Our results indicate that the generational model has important practical advantages and outperforms the existing methods in predicting field failures.« less

  18. Progressive Failure And Life Prediction of Ceramic and Textile Composites

    NASA Technical Reports Server (NTRS)

    Xue, David Y.; Shi, Yucheng; Katikala, Madhu; Johnston, William M., Jr.; Card, Michael F.

    1998-01-01

    An engineering approach to predict the fatigue life and progressive failure of multilayered composite and textile laminates is presented. Analytical models which account for matrix cracking, statistical fiber failures and nonlinear stress-strain behavior have been developed for both composites and textiles. The analysis method is based on a combined micromechanics, fracture mechanics and failure statistics analysis. Experimentally derived empirical coefficients are used to account for the interface of fiber and matrix, fiber strength, and fiber-matrix stiffness reductions. Similar approaches were applied to textiles using Repeating Unit Cells. In composite fatigue analysis, Walker's equation is applied for matrix fatigue cracking and Heywood's formulation is used for fiber strength fatigue degradation. The analysis has been compared with experiment with good agreement. Comparisons were made with Graphite-Epoxy, C/SiC and Nicalon/CAS composite materials. For textile materials, comparisons were made with triaxial braided and plain weave materials under biaxial or uniaxial tension. Fatigue predictions were compared with test data obtained from plain weave C/SiC materials tested at AS&M. Computer codes were developed to perform the analysis. Composite Progressive Failure Analysis for Laminates is contained in the code CPFail. Micromechanics Analysis for Textile Composites is contained in the code MicroTex. Both codes were adapted to run as subroutines for the finite element code ABAQUS and CPFail-ABAQUS and MicroTex-ABAQUS. Graphic user interface (GUI) was developed to connect CPFail and MicroTex with ABAQUS.

  19. Extubation of patients with neuromuscular weakness: a new management paradigm.

    PubMed

    Bach, John Robert; Gonçalves, Miguel R; Hamdani, Irram; Winck, Joao Carlos

    2010-05-01

    Successful extubation conventionally necessitates the passing of spontaneous breathing trials (SBTs) and ventilator weaning parameters. We report successful extubation of patients with neuromuscular disease (NMD) and weakness who could not pass them. NMD-specific extubation criteria and a new extubation protocol were developed. Data were collected on 157 consecutive "unweanable" patients, including 83 transferred from other hospitals who refused tracheostomies. They could not pass the SBTs before or after extubation. Once the pulse oxyhemoglobin saturation (Spo(2)) was maintained at > or = 95% in ambient air, patients were extubated to full noninvasive mechanical ventilation (NIV) support and aggressive mechanically assisted coughing (MAC). Rather than oxygen, NIV and MAC were used to maintain or return the Spo(2) to > or = 95%. Extubation success was defined as not requiring reintubation during the hospitalization and was considered as a function of diagnosis, preintubation NIV experience, and vital capacity and assisted cough peak flows (CPF) at extubation. Before hospitalization 96 (61%) patients had no experience with NIV, 41 (26%) used it < 24 h per day, and 20 (13%) were continuously NIV dependent. The first-attempt protocol extubation success rate was 95% (149 patients). All 98 extubation attempts on patients with assisted CPF > or = 160 L/m were successful. The dependence on continuous NIV and the duration of dependence prior to intubation correlated with extubation success (P < .005). Six of eight patients who initially failed extubation succeeded on subsequent attempts, so only two with no measurable assisted CPF underwent tracheotomy. Continuous volume-cycled NIV via oral interfaces and masks and MAC with oximetry feedback in ambient air can permit safe extubation of unweanable patients with NMD.

  20. Relational Neural Evolution Approach to Bank Failure Prediction

    NASA Astrophysics Data System (ADS)

    Abudu, Bolanle; Markose, Sheri

    2007-12-01

    Relational neural networks as a concept offers a unique opportunity for improving classification accuracy by exploiting relational structure in data. The premise is that a relational classification technique, which uses information implicit in relationships, should classify more accurately than techniques that only examine objects in isolation. In this paper, we study the use of relational neural networks for predicting bank failure. Alongside classical financial ratios normally used as predictor variables, we introduced new relational variables for the network. The relational neural network structure, specified as a combination of feed forward and recurrent neural networks, is determined by bank data through neuro-evolution. We discuss empirical results comparing performance of the relational approach to standard propositional methods used for bank failure prediction.

  1. A predictive model for failure properties of thermoset resins

    NASA Technical Reports Server (NTRS)

    Caruthers, James M.; Bowles, Kenneth J.

    1989-01-01

    A predictive model for the three-dimensional failure behavior of engineering polymers has been developed in a recent NASA-sponsored research program. This model acknowledges the underlying molecular deformation mechanisms and thus accounts for the effects of different chemical compositions, crosslink density, functionality of the curing agent, etc., on the complete nonlinear stress-strain response including yield. The material parameters required by the model can be determined from test-tube quantities of a new resin in only a few days. Thus, we can obtain a first-order prediction of the applicability of a new resin for an advanced aerospace application without synthesizing the large quantities of material needed for failure testing. This technology will effect order-of-magnitude reductions in the time and expense required to develop new engineering polymers.

  2. Relational Neural Evolution Approach to Bank Failure Prediction

    SciTech Connect

    Abudu, Bolanle; Markose, Sheri

    2007-12-26

    Relational neural networks as a concept offers a unique opportunity for improving classification accuracy by exploiting relational structure in data. The premise is that a relational classification technique, which uses information implicit in relationships, should classify more accurately than techniques that only examine objects in isolation. In this paper, we study the use of relational neural networks for predicting bank failure. Alongside classical financial ratios normally used as predictor variables, we introduced new relational variables for the network. The relational neural network structure, specified as a combination of feed forward and recurrent neural networks, is determined by bank data through neuro-evolution. We discuss empirical results comparing performance of the relational approach to standard propositional methods used for bank failure prediction.

  3. Prediction of hospital failure: a post-PPS analysis.

    PubMed

    Gardiner, L R; Oswald, S L; Jahera, J S

    1996-01-01

    This study investigates the ability of discriminant analysis to provide accurate predictions of hospital failure. Using data from the period following the introduction of the Prospective Payment System, we developed discriminant functions for each of two hospital ownership categories: not-for-profit and proprietary. The resulting discriminant models contain six and seven variables, respectively. For each ownership category, the variables represent four major aspects of financial health (liquidity, leverage, profitability, and efficiency) plus county marketshare and length of stay. The proportion of closed hospitals misclassified as open one year before closure does not exceed 0.05 for either ownership type. Our results show that discriminant functions based on a small set of financial and nonfinancial variables provide the capability to predict hospital failure reliably for both not-for-profit and proprietary hospitals.

  4. Predicting Failure of Glyburide Therapy in Gestational Diabetes

    PubMed Central

    Harper, Lorie M.; Glover, Angelica V.; Biggio, Joseph R.; Tita, Alan

    2016-01-01

    Objective We sought to develop a prediction model to identify women with gestational diabetes (GDM) who require insulin to achieve glycemic control. Study Design Retrospective cohort of all singletons with GDM treated with glyburide 2007–2013. Glyburide failure was defined as reaching glyburide 20 mg/day and receiving insulin. Glyburide success was defined as any glyburide dose without insulin and >70% of visits with glycemic control. Multivariable logistic regression analysis was performed to create a prediction model. Results Of 360 women, 63 (17.5%) qualified as glyburide failure and 157 (43.6%) glyburide success. The final prediction model for glyburide failure included prior GDM, GDM diagnosis ≤26 weeks, 1-hour GCT ≥228 mg/dL, 3-hour GTT 1-hour value ≥221 mg/dL, ≥7 post-prandial blood sugars >120 mg/dL in the week glyburide started, and ≥1 blood sugar >200 mg/dL. The model accurately classified 81% of subjects. Conclusions Women with GDM who will require insulin can be identified at initiation of pharmacologic therapy. PMID:26796130

  5. Mechanical performance of a dental composite: probabilistic failure prediction.

    PubMed

    van der Varst, P G; Brekelmans, W A; de Vree, J H; de Groot, R

    1993-08-01

    In clinical situations, the mechanical performances of dental structures--for example, composite restorations--depend on many factors. Most of them have a probabilistic character. Because composites are brittle materials, their strength should also be considered as a probabilistic quantity. For successful prediction of mechanical failure of structures consisting of these materials, a probabilistic approach is indispensable, and a suitable definition of equivalent stress must be introduced. An equivalent stress facilitates the transfer of strength data of laboratory specimens to situations where the stress state is much more complicated. The tensile and compressive strengths of composites differ considerably. Of two equivalent stress definitions that potentially describe this experimental fact (the Drücker-Prager and the Modified von Mises equivalent stress), the predictive capacity was investigated for a microfine composite. In a probabilistic approach to failure, use of the Drücker-Prager equivalent stress appeared to be superior, because the average failure load of notched beams was predicted with an error smaller than 8%.

  6. Predictive influence in the accelerated failure time model.

    PubMed

    Bedrick, Edward J; Exuzides, Alex; Johnson, Wesley O; Thurmond, Mark C

    2002-09-01

    We develop case deletion diagnostics for prediction of future observations in the accelerated failure time model. We view prediction to be an important inferential goal in a survival analysis and thus it is important to identify whether particular observations may be influencing the quality of predictions. We use the Kullback-Leibler divergence as a measure of the discrepancy between the estimated probability distributions for the full and the case-deleted samples. In particular, we focus on the effect of case deletion on estimated survival curves but where we regard the survival curve estimate as a vehicle for prediction. We also develop a diagnostic for assessing the effect of case deletion on inferences for the median time to failure. The estimated median can be used with both predictive and estimative purposes in mind. We also discuss the relationship between our suggested measures and the corresponding Cook distance measure, which was designed with the goal of assessing estimative influence. Several applications of the proposed diagnostics are presented.

  7. Comparison of the effectiveness of high flow nasal oxygen cannula vs. standard non-rebreather oxygen face mask in post-extubation intensive care unit patients.

    PubMed

    Brotfain, Evgeni; Zlotnik, Alexander; Schwartz, Andrei; Frenkel, Amit; Koyfman, Leonid; Gruenbaum, Shaun E; Klein, Moti

    2014-11-01

    Optimal oxygen supply is the cornerstone of the management of critically ill patients after extubation, especially in patients at high risk for extubation failure. In recent years, high flow oxygen system devices have offered an appropriate alternative to standard oxygen therapy devices such as conventional face masks and nasal prongs. To assess the clinical effects of high flow nasal cannula (HFNC) compared with standard oxygen face masks in Intensive Care Unit (ICU) patients after extubation. We retrospectively analyzed 67 consecutive ventilated critical care patients in the ICU over a period of 1 year. The patients were allocated to two treatment groups: HFNC (34 patients, group 1) and non-rebreathing oxygen face mask (NRB) (33 patients, group 2). Vital respiratory and hemodynamic parameters were assessed prior to extubation and 6 hours after extubation. The primary clinical outcomes measured were improvement in oxygenation, ventilation-free days, re-intubation, ICU length of stay, and mortality. The two groups demonstrated similar hemodynamic patterns before and after extubation. The respiratory rate was slightly elevated in both groups after extubation with no differences observed between groups. There were no statistically significant clinical differences in PaCO2. However, the use of HFNC resulted in improved PaO2/FiO2 post-extubation (P < 0.05). There were more ventilator-free days in the HFNC group (P< 0.05) and fewer patients required reintubation (1 vs. 6). There were no differences in ICU length of stay or mortality. This study demonstrated better oxygenation for patients treated with HFNC compared with NRB after extubation. HFNC may be more effective than standard oxygen supply devices for oxygenation in the post-extubation period.

  8. Pulse pressure can predict mortality in advanced heart failure.

    PubMed

    Ferreira, Ana Rita; Mendes, Sofia; Leite, Luís; Monteiro, Sílvia; Pego, Mariano

    2016-04-01

    Pulse pressure (PP) is the difference between systolic and diastolic blood pressure (BP). PP rises markedly after the fifth decade of life. High PP is a risk factor for the development of coronary heart disease and heart failure. The aim of this study was to assess whether PP can be used as a prognostic marker in advanced heart failure. We retrospectively studied patients in NYHA class III-IV who were hospitalized in a single heart failure unit between January 2003 and August 2012. Demographic characteristics, laboratory tests, and cardiovascular risk factors were recorded. PP was calculated as the difference between systolic and diastolic BP at admission, and the patients were divided into two groups (group 1: PP >40 mmHg and group 2: PP ≤40 mmHg). Median follow-up was 666 ± 50 days for the occurrence of cardiovascular death and heart transplantation. During follow-up 914 patients in NYHA class III-IV were hospitalized, 520 in group 1 and 394 in group 2. The most important difference between the groups was in left ventricular dysfunction, which was greater in patients with lower PP. On Kaplan-Meier analysis, group 2 had higher mortality (38 vs. 24 patients, log-rank p=0.002). PP is easily calculated, and enables prediction of cardiovascular death in patients with advanced heart failure. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  9. Feasibility of Intraoperative Extubation in Pediatric Heart Transplantation.

    PubMed

    Schnittman, Samuel R; Rashid, Saima; Egbe, Alexander; Love, Barry; Nguyen, Khanh; Mittnacht, Alexander J C; Weiss, Aaron J

    2017-09-01

    Based on described benefits of fast-tracking and early extubation in children undergoing congenital heart surgery, we applied this concept to selected children following uncomplicated orthotopic heart transplantation (OHT). In this case series, we report four patients who were extubated immediately after surgery in the operating room. A mild respiratory acidosis and hypercapnia were noted on the initial arterial blood gases, were well tolerated, and were normalized within 6 to 12 hours. There was no mortality among patients who were extubated in the operating room, and no patients required reintubation. We conclude that operating room extubation is feasible in selected patients undergoing OHT.

  10. Machine-Learning Algorithms Predict Graft Failure After Liver Transplantation.

    PubMed

    Lau, Lawrence; Kankanige, Yamuna; Rubinstein, Benjamin; Jones, Robert; Christophi, Christopher; Muralidharan, Vijayaragavan; Bailey, James

    2017-04-01

    The ability to predict graft failure or primary nonfunction at liver transplant decision time assists utilization of scarce resource of donor livers, while ensuring that patients who are urgently requiring a liver transplant are prioritized. An index that is derived to predict graft failure using donor and recipient factors, based on local data sets, will be more beneficial in the Australian context. Liver transplant data from the Austin Hospital, Melbourne, Australia, from 2010 to 2013 has been included in the study. The top 15 donor, recipient, and transplant factors influencing the outcome of graft failure within 30 days were selected using a machine learning methodology. An algorithm predicting the outcome of interest was developed using those factors. Donor Risk Index predicts the outcome with an area under the receiver operating characteristic curve (AUC-ROC) value of 0.680 (95% confidence interval [CI], 0.669-0.690). The combination of the factors used in Donor Risk Index with the model for end-stage liver disease score yields an AUC-ROC of 0.764 (95% CI, 0.756-0.771), whereas survival outcomes after liver transplantation score obtains an AUC-ROC of 0.638 (95% CI, 0.632-0.645). The top 15 donor and recipient characteristics within random forests results in an AUC-ROC of 0.818 (95% CI, 0.812-0.824). Using donor, transplant, and recipient characteristics known at the decision time of a transplant, high accuracy in matching donors and recipients can be achieved, potentially providing assistance with clinical decision making.

  11. Prediction of long-term failure in Kevlar 49 composites

    SciTech Connect

    Gerstle, F.P. Jr.

    1982-01-01

    Creep rupture data in Kevlar 49 epoxy usually exhibit considerable scatter: the coefficient of variation (CV) about the mean failure time at a given stress exceeds 100%. Quasi-static strength data, in contrast, shows little scatter: <4% CV for pressure vessels and <10% for impregnated strands. In this paper analysis of existing creep rupture data on Kevlar epoxy vessels at four storage pressures has produced an interesting and useful result. It was found that a significant portion of the scatter in failure times for pressure vessels is due to spool-to-spool variation in the eight spools of Kevlar fibers used to wind the vessels. The order rank of mean times to failure was consistent over a pressure range from 3400 to 4300 psi, 68 to 86% of short term burst. Also, the coefficient of variation about the mean failure time for each spool was less than that for the total sample. The statistical inference that the sample is nonhomogeneous was supported by a nonparametric check using the Kruskal-Wallis test, and by a parametric analysis of variance. The order rank found in long-term tests did not unequivocally agree with static strength ranks; several spool sets were distinctly high or low. The implication is that, while static strengths are not valid predictors of long-term behavior, short term creep rupture tests at high stress definitely are. The material difference which causes the spool-to-spool variations has not yet been identified for all eight spools. However, it appears that Kevlar behavior at lower pressures may be predicted through the use of curves fitted to the data for each spool. A power law relating failure time to pressure, t = t/sub 0/(p/p/sub 0/)/sup m/, was found to fit the data reasonably well. The implication is that, both in composite vessel design and in creep rupture experiments, the pressure (or stress) level be carefully controlled.

  12. HDL Cholesterol Efflux Predicts Graft Failure in Renal Transplant Recipients

    PubMed Central

    Annema, Wijtske; Dikkers, Arne; Freark de Boer, Jan; Dullaart, Robin P. F.; Sanders, Jan-Stephan F.; Bakker, Stephan J. L.

    2016-01-01

    High-density lipoprotein (HDL) particles are involved in the protection against cardiovascular disease by promoting cholesterol efflux, in which accumulated cholesterol is removed from macrophage foam cells. We investigated whether HDL cholesterol efflux capacity is associated with cardiovascular mortality, all-cause mortality, and graft failure in a cohort of renal transplant recipients (n=495, median follow-up 7.0 years). Cholesterol efflux capacity at baseline was quantified using incubation of human macrophage foam cells with apolipoprotein B–depleted plasma. Baseline efflux capacity was not different in deceased patients and survivors (P=0.60 or P=0.50 for cardiovascular or all-cause mortality, respectively), whereas recipients developing graft failure had lower efflux capacity than those with functioning grafts (P<0.001). Kaplan–Meier analysis demonstrated a lower risk for graft failure (P=0.004) but not cardiovascular (P=0.30) or all-cause mortality (P=0.31) with increasing gender-stratified tertiles of efflux capacity. Cox regression analyses adjusted for age and gender showed that efflux capacity was not associated with cardiovascular mortality (hazard ratio [HR], 0.89; 95% confidence interval [95% CI], 0.67 to 1.19; P=0.43). Furthermore, the association between efflux capacity and all-cause mortality (HR, .79; 95% CI, 0.63 to 0.98; P=0.031) disappeared after further adjustment for potential confounders. However, efflux capacity at baseline significantly predicted graft failure (HR, 0.43; 95% CI, 0.29 to 0.64; P<0.001) independent of apolipoprotein A-I, HDL cholesterol, or creatinine clearance. In conclusion, this prospective study shows that cholesterol efflux capacity from macrophage foam cells is not associated with cardiovascular or all-cause mortality but is a strong predictor of graft failure independent of plasma HDL cholesterol levels in renal transplant recipients. PMID:26319244

  13. What is the optimal rate of failed extubation?

    PubMed Central

    2012-01-01

    Failed extubation (FE), defined as reintubation 48 or 72 hours after planned extubation, occurs in a significant percentage of patients and is associated with a substantial burden of morbidity and mortality. This commentary reviews the literature describing FE rates and the clinical consequences of FE and proposes an 'optimal' rate of FE as well as avenues for future research. PMID:22356725

  14. Tracheal extubation in children: halothane versus isoflurane, anesthetized versus awake.

    PubMed

    Pounder, D R; Blackstock, D; Steward, D J

    1991-04-01

    The authors compared the incidence of respiratory complications and arterial hemoglobin desaturation during emergence from anesthesia in children whose tracheas were extubated while they were anesthetized or after they were awake and to whom halothane or isoflurane had been administered. One hundred children 1-4 yr of age undergoing minor urologic surgery were studied. After a standard induction technique, patients were randomized to receive either isoflurane or halothane. In 50 patients tracheal extubation was performed while they were breathing 2 MAC of either halothane or isoflurane in 100% oxygen. The remaining 50 patients received 2 MAC (volatile agent plus nitrous oxide) during the operation, but tracheal extubation was delayed until they were awake. A blinded observer recorded the incidence of respiratory complications and continuously measured hemoglobin saturation for 15 min after extubation. When tracheal extubation occurred in deeply anesthetized patients, no differences were found between the two volatile agents. When tracheal extubation of awake patients was performed, the use of isoflurane was associated with more episodes of coughing and airway obstruction than was halothane (P less than 0.05). Awake tracheal extubation following either agent was associated with significantly more episodes of hemoglobin desaturation than was tracheal extubation while anesthetized.

  15. Rational temporal predictions can underlie apparent failures to delay gratification

    PubMed Central

    McGuire, Joseph T.; Kable, Joseph W.

    2013-01-01

    An important category of seemingly maladaptive decisions involves failure to postpone gratification. A person pursuing a desirable long-run outcome may abandon it in favor of a short-run alternative that has been available all along. Here we present a theoretical framework in which this seemingly irrational behavior emerges from stable preferences and veridical judgments. Our account recognizes that decision makers generally face uncertainty regarding the time at which future outcomes will materialize. When timing is uncertain, the value of persistence depends crucially on the nature of a decision-maker’s prior temporal beliefs. Certain forms of temporal beliefs imply that a delay’s predicted remaining length increases as a function of time already waited. In this type of situation, the rational, utility-maximizing strategy is to persist for a limited amount of time and then give up. We show empirically that people’s explicit predictions of remaining delay lengths indeed increase as a function of elapsed time in several relevant domains, implying that temporal judgments offer a rational basis for limiting persistence. We then develop our framework into a simple working model and show how it accounts for individual differences in a laboratory task (the well-known “marshmallow test”). We conclude that delay-of-gratification failure, generally viewed as a manifestation of limited self-control capacity, can instead arise as an adaptive response to the perceived statistics of one’s environment. PMID:23458085

  16. An Interprofessional Quality Improvement Initiative to Standardize Pediatric Extubation Readiness Assessment.

    PubMed

    Abu-Sultaneh, Samer; Hole, Acrista J; Tori, Alvaro J; Benneyworth, Brian D; Lutfi, Riad; Mastropietro, Christopher W

    2017-10-01

    Establishing protocols to wean mechanical ventilation and assess readiness for extubation, with the goal of minimizing morbidity associated with extubation failure and prolonged mechanical ventilation, have become increasingly important in contemporary PICUs. The aim of this quality improvement initiative is to establish a respiratory therapist-led daily spontaneous breathing trial protocol to standardize extubation readiness assessment and documentation in our PICU. A quality improvement project. Single center, tertiary care Children's Hospital PICU. All intubated patients admitted to PICU requiring conventional mechanical ventilation between February 2013 and January 2016. A working group of pediatric intensivists, respiratory therapists, nurses, and information technology specialists established the protocol, standardized documentation via the electronic medical record, and planned education. Daily spontaneous breathing trial protocol implementation began in February 2015. All patients on mechanical ventilation were screened daily at approximately 4 AM by a respiratory therapist to determine daily spontaneous breathing trial eligibility. If all screening criteria were met, patients were placed on continuous positive airway pressure of 5 cm H2O with pressure support of 8 cm H2O for up to 2 hours. If tolerated, patients would be extubated to supplemental oxygen delivered via nasal cannula in the morning, after intensivist approval. Daily audits were done to assess screening compliance and accuracy of documentation. We analyzed data from 398 mechanically ventilated patients during daily spontaneous breathing trial period (February 2015-January 2016), compared with 833 patients from the pre-daily spontaneous breathing trial period (February 2013-January 2015). During the daily spontaneous breathing trial period, daily screening occurred in 92% of patients. Extubation failure decreased from 7.8% in the pre-daily spontaneous breathing trial period to 4.5% in daily

  17. Early prediction of organ failure under the revised Atlanta classification.

    PubMed

    Liu, Jian; Cao, Feng; Dong, Xiao Min; Li, Peng Yu; Li, Hai Chao; Qi, Bao Ju; Li, Fei

    2017-01-01

    This study aimed to compare the ability of conventional laboratory markers and scoring systems to early predict organ failure (OF) and to differentiate between transient and persistent OF in patients with acute pancreatitis (AP) using the revised Atlanta classification. We retrospectively analyzed the medical records of 214 patients with AP between January 2014 and July 2015. The predictive values of laboratory markers were analyzed. The predictive accuracy of individual markers, extrapancreatic inflammation on computed tomography (EPIC), acute physiology and chronic health evaluation II (APACHE II), and bedside index for severity in acute pancreatitis (BISAP) scores were measured using the area under the receiver operating characteristic curve (AUROC). OF was diagnosed in 32 (15%) patients and persistent OF in 14 (6.5%). There were statistically significant differences between patients with and without OF with respect to white blood cell count, creatinine, blood urea nitrogen, lactate dehydrogenase, C-reactive protein, calcium (Ca), arterial partial pressure of oxygen (PaO2), base excess (BE), APACHE II, BISAP scores, and EPIC scores. Logistic regression analysis identified Ca, PaO2, and BE as independent predictors of OF. Using AUROC, the EPIC score had the highest accuracy for the early prediction of OF, which was 0.82. No significant differences were detected between patients with transient and persistent OF. Several laboratory markers and score systems were useful for the early prediction of OF in patients with AP, of which Ca, PaO2, and BE had highest predicting value, and EPIC score had the highest accuracy. We could not predict the duration of OF using laboratory markers.

  18. [Low dose propofol vs. lidocaine for relief of resistant post-extubation laryngospasm in the obstetric patient].

    PubMed

    Mokhtar, Ali M; Badawy, Ahmed A

    2017-07-25

    Post-extubation laryngospasm is a dangerous complication that should be managed promptly. Standard measures were described for its management. We aimed to compare the efficacy of propofol (0.5mg.kg(-1)) vs. lidocaine (1.5mg.kg(-1)) for treatment of resistant post-extubation laryngospasm in the obstetric patients, after failure of the standard measures. This study was conducted over 2 years on all obstetric patients scheduled for cesarean delivery. Post-extubation laryngospasm was initially managed with a standard protocol (removal of offending stimulus, jaw thrust, positive pressure ventilation with 100% oxygen). When this protocol failed, the tested drug was the second line (lidocaine in the first year and propofol in the second year). Lastly, succinylcholine was used when the tested drug failed. In lidocaine group, 5% of parturients developed post-extubation laryngospasm, 31.9% of them were successfully treated via standard protocol, and 68.1% required lidocaine treatment. 65.6% of patients treated with lidocaine responded successfully and 34.4% required succinylcholine to relieve laryngospasm. In propofol group, 4.7% of parturients developed post-extubation laryngospasm, 30.1% of them were successfully treated via standard protocol, and 69.9% required propofol treatment. 82.8% of patients treated with propofol responded successfully and 17.2% required succinylcholine to relieve laryngospasm. Small dose of propofol (0.5mg.kg(-1)) is marginally more effective than lidocaine (1.5mg.kg(-1)) for the treatment of resistant post-extubation laryngospasm in obstetric patients, after failure of standard measures and before the use of muscle relaxants. Copyright © 2017 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  19. Out-of-bed extubation: a feasibility study

    PubMed Central

    Dexheimer Neto, Felippe Leopoldo; Vesz, Patrini Silveira; Cremonese, Rafael Viegas; Leães, Clarissa Garcia Soares; Raupp, Ana Carolina Tabajara; Rodrigues, Cristiano dos Santos; de Andrade, Juliana Mara Stormovski; Townsend, Raquel da Silva; Maccari, Juçara Gasparetto; Teixeira, Cassiano

    2014-01-01

    Objective In clinical intensive care practice, weaning from mechanical ventilation is accompanied by concurrent early patient mobilization. The aim of this study was to compare the success of extubation performed with patients seated in an armchair compared to extubation with patients in a supine position. Methods A retrospective study, observational and non-randomized was conducted in a mixed-gender, 23-bed intensive care unit. The primary study outcome was success of extubation, which was defined as the patient tolerating the removal of the endotracheal tube for at least 48 hours. The differences between the study groups were assessed using Student's t-test and chi-squared analysis. Results Ninety-one patients were included from December 2010 and June 2011. The study population had a mean age of 71 years ± 12 months, a mean APACHE II score of 21±7.6, and a mean length of mechanical ventilation of 2.6±2 days. Extubation was performed in 33 patients who were seated in an armchair (36%) and in 58 patients in a supine position (64%). There were no significant differences in age, mean APACHE II score or length of mechanical ventilation between the two groups, and a similar extubation success rate was observed (82%, seated group versus 85%, supine group, p>0.05). Furthermore, no significant differences were found between the two groups in terms of post-extubation distress, need for tracheostomy, duration of mechanical ventilation weaning, or intensive care unit stay. Conclusion Our results suggest that the clinical outcomes of patients extubated in a seated position are similar to those of patients extubated in a supine position. This new practice of seated extubation was not associated with adverse events and allowed extubation to occur simultaneously with early mobilization. PMID:25295820

  20. Anterior uterocervical angle measurement improves prediction of cerclage failure.

    PubMed

    Knight, J C; Tenbrink, E; Sheng, J; Patil, A S

    2017-04-01

    To compare the anterior uterocervical angle and cervical length as predictors of spontaneous preterm delivery in patients with transvaginal cerclage. We retrospectively evaluated a cohort of 142 pregnant women with transvaginal cerclage placed over a 5-year period (2010 to 2015) were evaluated. Cervical morphology characteristics were measured from endovaginal imaging, including cervical length, cerclage height, funnel volume and anterior uterocervical angle prior to cerclage placement (UCA 1), shortly after cerclage placement (UCA 2) and the last image prior to delivery (UCA 3). Cerclage failure was defined as delivery prior to 36 weeks. Univariate analysis, receiver operator characteristic curves and binary logistic regression were used for statistical analysis. Statistical significance was defined as a P<0.05. Among the 142 women with a transvaginal cerclage, 38% had cerclage failure. The mean gestational age at birth was 29.3±5.2 weeks in the failure group compared with 37.9±2.8 weeks in those that did not fail (P<0.001). Univariate analysis identified cervical length (P=0.034) and UCA 3 (P<0.001) as significantly associated with gestational age at birth. Receiver operator characteristic curves demonstrated improved prediction of delivery prior to 34 weeks at UCA 3=108(o) (97% sensitivity, 65% specificity) compared to a cervical length of 25 mm. At <28 weeks, optimal performance of UCA 3 was found at 112(o) (100% sensitivity, 62% specificity) compared with cervical length of 25 mm (29% sensitivity, 39% specificity). Binary logistic regression revealed UCA 3>108(o) conferred an OR 35.1 (95% CI 7.7 to 160.3) for delivery prior to 34 weeks, and UCA 3>112(o) an OR 42.0 (95% CI 5.3 to 332.1) for delivery prior to 28 weeks. In comparison, CL<25 mm had an OR 4.7 (95% CI 1.8 to 12.2) for delivery prior to 34 weeks and OR 6.0 (95% CI 1.9 to 19.3) prior to 28 weeks. In patients with transvaginal cerclage, an increasingly obtuse anterior uterocervical angle

  1. Fast Track Extubation In Adult Patients On Pump Open Heart Surgery At A Tertiary Care Hospital.

    PubMed

    Akhtar, Mohammad Irfan; Sharif, Hasanat; Hamid, Mohammad; Samad, Khalid; Khan, Fazal Hameed

    2016-01-01

    Fast-track cardiac surgery programs have been established as the standard of cardiac surgical care. Studies have shown that early extubation in elective cardiac surgery patients, including coronary and non-coronary open-heart surgery patients does not increase perioperative morbidity and mortality. The objective of this observational study was to determine the success and failure profile of fast track extubation (FTE) practice in adult open-heart surgical patients. The study was conducted at cardiac operating room and Cardiac Intensive Care Unit (CICU) of a tertiary care hospital for a period of nine months, i.e., from Oct 2014 to June-2015. All on pump elective adult cardiac surgery patients including isolated CABG, isolated Valve replacements, combined procedures and aortic root replacements were enrolled in the study. Standardized anesthetic technique was adopted. Surgical and bypass techniques were tailored according to the procedure. Success of Fast track extubation was defined as extubation within 6 hours of arrival in CICU. A total of 290 patients were recruited. The average age of the patients was 56.3±10.5 years. There were 77.6% male and 22.4% female patients. Overall success rate was 51.9% and failure rate was 48.1%. The peri-operative renal insufficiency, cross clamp time and CICU stay (hours) were significantly lower in success group. Re-intubation rate was 0.74%. The perioperative parameters were significantly better in success group and the safety was also demonstrated in the patients who were fast tracked successfully. To implement the practice in its full capacity and benefit, a fast track protocol needs to be devised to standardize the current practices and to disseminate the strategy among junior anaesthesiologists, perfusionists and nursing staff.

  2. Can diaphragmatic ultrasonography performed during the T-tube trial predict weaning failure? The role of diaphragmatic rapid shallow breathing index.

    PubMed

    Spadaro, Savino; Grasso, Salvatore; Mauri, Tommaso; Dalla Corte, Francesca; Alvisi, Valentina; Ragazzi, Riccardo; Cricca, Valentina; Biondi, Giulia; Di Mussi, Rossella; Marangoni, Elisabetta; Volta, Carlo Alberto

    2016-09-28

    The rapid shallow breathing index (RSBI), which is the ratio between respiratory rate (RR) and tidal volume (VT), is one of the most widely used indices to predict weaning outcome. Whereas the diaphragm plays a fundamental role in generating VT, in the case of diaphragmatic dysfunction the inspiratory accessory muscles may contribute. If this occurs during a weaning trial, delayed weaning failure is likely since the accessory muscles are more fatigable than the diaphragm. Hence, we hypothesised that the traditional RSBI could be implemented by substituting VT with the ultrasonographic evaluation of diaphragmatic displacement (DD). We named the new index the diaphragmatic-RSBI (D-RSBI). The aim of this study was to compare the ability of the traditional RSBI and D-RSBI to predict weaning failure in ready-to-wean patients. We performed a prospective observational study. During a T-tube spontaneous breathing trial (SBT) we simultaneously evaluated right hemidiaphragm displacement (i.e., DD) by using M-mode ultrasonography as well as the RSBI. Outcome of the weaning attempt, length of mechanical ventilation, length of intensive care unit and hospital stay, and hospital mortality were recorded. Receiver operator characteristic (ROC) curves were used to evaluate the diagnostic accuracy of D-RSBI and RSBI. We enrolled 51 patients requiring mechanical ventilation for more than 48 h who were ready to perform a SBT. Most of the patients, 34 (66 %), were successfully weaned from mechanical ventilation. When considering the 17 patients that failed the weaning attempt, 11 (64 %) had to be reconnected to the ventilator during the SBT, three (18 %) had to be re-intubated within 48 h of extubation, and three (18 %) required non-invasive ventilation support within 48 h of extubation. The areas under the ROC curves for D-RSBI and RSBI were 0.89 and 0.72, respectively (P = 0.006). D-RSBI (RR/DD) was more accurate than traditional RSBI (RR/VT) in predicting the weaning

  3. Predicting multiple organ failure in patients with severe trauma

    PubMed Central

    Lausevic, Zeljko; Lausevic, Mirjana; Trbojevic-Stankovic, Jasna; Krstic, Slobodan; Stojimirovic, Biljana

    2008-01-01

    Objective Pathophysiological processes in the first days after trauma seem to be important for the development and final outcome in cases of multiple organ failure (MOF). Our objective in this study was to assess the kinetics of C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-10 (IL-10) and phospholipase A2 group II (PLA2-II) as predictors of more severe forms of MOF. As well, we sought to assess the criteria for systemic inflammatory response syndrome (SIRS) and Simplified Acute Physiology Score (SAPS II) values and to create predictive models of MOF development. Methods This prospective study recruited a sample from 75 patients treated for severe injuries at surgical intensive care units at the Clinical Center of Serbia. Of these patients, a total of 65 met the entry criteria, which included an Injury Severity Score ≥ 18 (severe injury), age range 16–65 years, admission to the hospital within the first 24 hours after injury and survival longer then 48 hours. We excluded patients with primary injury to the central nervous system. Results When patients with and without MOF were compared, a statistically significant difference was noted in the average CRP and PLA2II levels on all days. IL-6 and IL-10 concentrations were significantly different on all days of hospitalization. Conclusion According to the results of our study, it is possible to create predictive models with a high level of accuracy for the development of organ failure in traumatized patients. The most important parameters of MOF development are serum IL-6 concentration on the first day of hospitalization and the number of positive SIRS criteria on the fourth day of hospitalization. PMID:18377749

  4. Prediction of postoperative dyspnea and chronic respiratory failure.

    PubMed

    Murakami, Junichi; Ueda, Kazuhiro; Sano, Fumiho; Hayashi, Masataro; Tanaka, Nobuyuki; Hamano, Kimikazu

    2015-05-01

    Even among patients considered to be functionally eligible for major lung resection, some experience postoperative dyspnea. Based on our previous study with quantitative computed tomography (CT), we hypothesized that postoperative dyspnea is associated with the collapse of the remaining lung, and thus, prediction of the postoperative lung volume may contribute to risk assessment for postoperative dyspnea. We measured the emphysematous lung volume and functional lung volume (FLV) separately on whole lung CT using an image analysis software in 290 patients undergoing major lung resection for cancer between January 2006 and December 2012. The postoperative FLV was predicted by a stepwise multiple regression analysis. Fourteen patients complained of postoperative dyspnea (complicated group), five of them presented with chronic respiratory failure. The postoperatively measured FLV was significantly lower in the complicated group than in the control group (P < 0.01). The postoperative FLV could be calculated using preoperative variables, including the forced vital capacity, number of resected segments, FLV, and emphysematous lung volume. The predicted postoperative FLV was significantly lower in the complicated group than in the control group (P < 0.01, area under the curve = 0.78; sensitivity 86%; specificity 73%). The predicted postoperative FLV was also useful in distinguishing complicated patients from matched-control patients who had similar preoperative pulmonary function (P = 0.02). Postoperative dyspnea is likely accompanied by a collapse of the remaining lung. Quantitative assessment of the lung morphology on preoperative CT is useful to screen for patients at risk of postoperative dyspnea. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Use of Biomarkers to Predict Readmission for Congestive Heart Failure.

    PubMed

    Sudharshan, Sangita; Novak, Eric; Hock, Karl; Scott, Mitchell G; Geltman, Edward M

    2017-02-01

    Acute decompensated heart failure (ADHF) is a major reason for repeated hospitalizations. Identifying those patients with ADHF at risk for readmission is critical so that preventive interventions can be implemented. Biomarkers such as B-type natriuretic peptide (BNP), high-sensitivity troponin I, and galectin-3 (Gal-3) assessed at discharge may be useful, although their role in predicting short-term readmission is not well defined in the literature. We enrolled and had follow-up data for 101 participants admitted to our facility from April 2013 to March 2015 with a primary diagnosis of ADHF. Gal-3, high-sensitivity troponin I, and BNP were obtained within 48 hours before hospital discharge after management of ADHF. Gal-3 was assessed using 2 commercially available assays. We compared subjects who were and were not readmitted. Discharge BNP was found to be a significant predictor of 30- and 60-day readmission (area under the curve [AUC] 0.69 [p = 0.046], AUC 0.7 [p = 0.005], respectively). The addition of Gal-3 to discharge BNP provided significantly improved prediction of 60-day readmission. Gal-3 alone was found to be a significant predictor of 60-day readmission in patients with preserved ejection fraction (AUC 0.85, p <0.001). The net reclassification improvement was 55.2 (p = 0.037). Using multivariate analysis, for every 100 pg/L BNP increase, the probability of readmission increased by approximately 10%, and for every 1-ng/ml Gal-3 increase, the probability further increased 8%. A statistically significant net reclassification improvement was not found on examination of 30-day readmission. In conclusion, measurement of both Gal-3 and BNP at hospital discharge provides significant prediction of hospital readmission within 60 days. When combined, the prediction of readmission is significantly improved.

  6. A mixture Weibull proportional hazard model for mechanical system failure prediction utilising lifetime and monitoring data

    NASA Astrophysics Data System (ADS)

    Zhang, Qing; Hua, Cheng; Xu, Guanghua

    2014-02-01

    As mechanical systems increase in complexity, it is becoming more and more common to observe multiple failure modes. The system failure can be regarded as the result of interaction and competition between different failure modes. It is therefore necessary to combine multiple failure modes when analysing the failure of an overall system. In this paper, a mixture Weibull proportional hazard model (MWPHM) is proposed to predict the failure of a mechanical system with multiple failure modes. The mixed model parameters are estimated by combining historical lifetime and monitoring data of all failure modes. In addition, the system failure probability density is obtained by proportionally mixing the failure probability density of multiple failure modes. Monitoring data are input into the MWPHM to estimate the system reliability and predict the system failure time. A simulated sample set is used to verify the ability of the MWPHM to model multiple failure modes. Finally, the MWPHM and the traditional Weibull proportional hazard model (WPHM) are applied to a high-pressure water descaling pump, which has two failure modes: sealing ring wear and thrust bearing damage. Results show that the MWPHM is greatly superior in system failure prediction to the WPHM.

  7. Diagnosis and treatment of post-extubation dysphagia: Results from a National Survey

    PubMed Central

    Macht, Madison; Wimbish, Tim; Clark, Brendan J.; Benson, Alexander B.; Burnham, Ellen L.; Williams, André; Moss, Marc

    2012-01-01

    Purpose This study sought to determine the utilization of speech-language pathologist (SLPs) for the diagnosis and treatment of post-extubation dysphagia in survivors of mechanical ventilation. Methods We designed, validated, and mailed a survey to 1,966 inpatient SLPs who routinely evaluate patients for post-extubation dysphagia. Results The majority of SLP diagnostic evaluations (60%; 95% CI = 59–62%) were performed using clinical techniques with uncertain accuracy. Instrumental diagnostic tests (such as fluoroscopy and endoscopy) are more likely to be available at university than community hospitals. After adjusting for hospital size and academic affiliation, instrumental test use varied significantly by geographical region. Treatments for post-extubation dysphagia usually involved dietary adjustment (76%; 95% CI = 73–79%) and postural changes/compensatory maneuvers (86%; 95% CI = 84–88%), rather than on interventions aimed to improve swallowing function (24%; 95% CI = 21–27%). Conclusions SLPs frequently evaluate acute respiratory failure survivors. However, diagnostic evaluations rely mainly upon bedside techniques with uncertain accuracy. The use of instrumental tests varies by geographic location and university affiliation. Current diagnostic practices and feeding decisions for critically ill patients should be viewed with caution until further studies determine the accuracy of bedside detection methods. PMID:23084136

  8. Diagnosis and treatment of post-extubation dysphagia: results from a national survey.

    PubMed

    Macht, Madison; Wimbish, Tim; Clark, Brendan J; Benson, Alexander B; Burnham, Ellen L; Williams, André; Moss, Marc

    2012-12-01

    This study sought to determine the utilization of speech-language pathologist (SLPs) for the diagnosis and treatment of post-extubation dysphagia in survivors of mechanical ventilation. We designed, validated, and mailed a survey to 1,966 inpatient SLPs who routinely evaluate patients for post-extubation dysphagia. Most SLP diagnostic evaluations (60%; 95% CI, 59%-62%) were performed using clinical techniques with uncertain accuracy. Instrumental diagnostic tests (such as fluoroscopy and endoscopy) are more likely to be available at university than community hospitals. After adjusting for hospital size and academic affiliation, instrumental test use varied significantly by geographical region. Treatments for post-extubation dysphagia usually involved dietary adjustment (76%; 95% CI, 73-79%) and postural changes/compensatory maneuvers (86%; 95% CI, 84-88%), rather than on interventions aimed to improve swallowing function (24%; 95% CI, 21-27%). SLPs frequently evaluate acute respiratory failure survivors. However, diagnostic evaluations rely mainly upon bedside techniques with uncertain accuracy. The use of instrumental tests varies by geographic location and university affiliation. Current diagnostic practices and feeding decisions for critically ill patients should be viewed with caution until further studies determine the accuracy of bedside detection methods. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Experimental verification of prediction method for electromigration failure of polycrystalline lines

    NASA Astrophysics Data System (ADS)

    Sasagawa, Kazuhiko; Naito, Kazushi; Kimura, Hiroki; Saka, Masumi; Abé, Hiroyuki

    2000-03-01

    A prediction method for electromigration failure in polycrystalline lines has been proposed using the governing parameter of electromigration damage, the atomic flux divergence (AFDgen), and the usefulness has been verified by experiment where various line shapes were treated under various operating conditions. In the prediction method, lifetime and failure site in a metal line have been predicted by numerical simulation of the processes of void initiation, its growth, to line failure. The simulation has predicted accurately the lifetime as well as the failure site of the metal line. In the verification, however, the metal lines treated had the same grain size, that is, the same microstructure. In this article, the prediction method for the electromigration failure of polycrystalline lines was verified in more detail, by comparing the prediction results of lifetime and failure site with the results of experiments using not only various shaped lines but also lines whose microstructures were different.

  10. Decreasing body temperature predicts early rehospitalization in congestive heart failure.

    PubMed

    Ahmed, Amany; Aboshady, Ibrahim; Munir, Shahzeb M; Gondi, Sreedevi; Brewer, Alan; Gertz, S David; Lai, Dejian; Shaik, Naushad A; Shankar, K J; Deswal, Anita; Casscells, S Ward

    2008-08-01

    In congestive heart failure (CHF), a low body temperature at hospital admission predicts in-hospital mortality. We hypothesized that a postdischarge reduction in body temperature predicts early CHF rehospitalization and death. We reviewed the records of 198 patients discharged after CHF hospitalization. We categorized the patients as hypothermic or normothermic (cutoff point, 36.3 degrees C/97.4 degrees F) according to body temperature at discharge. We classified the 2 groups according to the direction of temperature change between discharge and the first follow-up visit: normothermic/non-decreasing temperature (N+), normothermic/decreasing temperature (N-), hypothermic/non-decreasing temperature (H+), and hypothermic/decreasing temperature (H-). Ninety-three patients (47%) had decreasing temperatures, and 105 patients (53%) had non-decreasing temperatures. Kaplan-Meier analysis revealed a significant intergroup difference in survival (P = .01) and rehospitalization time (P = .005). On logistic regression, a decreasing temperature was significantly associated with rehospitalization within 180 days (odds ratio, 4.01; 95% confidence interval, 1.63-10.02; P = .003). On Cox regression, the hazard ratios for death were 3.19 (P = .07), 6.49 (P = .004), and 5.17 (P = .07), for the N-, H+, and H- groups, respectively, versus the N+ group. For rehospitalization time, the hazard ratios were 7.02 (P = .01), 4.24 (P = .08), and 13.43 (P = .005) for the N-, H+, and H- groups, respectively, versus the N+ group. Decreasing body temperatures can predict readmission, decreased time to rehospitalization, and (in combination with hypothermia) decreased survival.

  11. Flood Water Level Mapping and Prediction Due to Dam Failures

    NASA Astrophysics Data System (ADS)

    Musa, S.; Adnan, M. S.; Ahmad, N. A.; Ayob, S.

    2016-07-01

    Sembrong dam has undergone overflow failure. Flooding has been reported to hit the town, covering an area of up to Parit Raja, located in the district of Batu Pahat. This study aims to identify the areas that will be affected by flood in the event of a dam failure in Sembrong Dam, Kluang, Johor at a maximum level. To grasp the extent, the flood inundation maps have been generated by using the InfoWorks ICM and GIS software. By using these maps, information such as the depth and extent of floods can be identified the main ares flooded. The flood map was created starting with the collection of relevant data such as measuring the depth of the river and a maximum flow rate for Sembrong Dam. The data were obtained from the Drainage and Irrigation Department Malaysia and the Department of Survey and Mapping and HLA Associates Sdn. Bhd. Then, the data were analyzed according to the established Info Works ICM method. The results found that the flooded area were listed at Sri Lalang, Parit Sagil, Parit Sonto, Sri Paya, Parit Raja, Parit Sempadan, Talang Bunut, Asam Bubok, Tanjung Sembrong, Sungai Rambut and Parit Haji Talib. Flood depth obtained for the related area started from 0.5 m up to 1.2 m. As a conclusion, the flood emanating from this study include the area around the town of Ayer Hitam up to Parit Raja approximately of more than 20 km distance. This may give bad implication to residents around these areas. In future studies, other rivers such as Sungai Batu Pahat should be considered for this study to predict and reduce the yearly flood victims for this area.

  12. Factors influencing the predictive power of models for predicting mortality and/or heart failure hospitalization in patients with heart failure.

    PubMed

    Ouwerkerk, Wouter; Voors, Adriaan A; Zwinderman, Aeilko H

    2014-10-01

    The present paper systematically reviews and compares existing prediction models in order to establish the strongest variables, models, and model characteristics in patients with heart failure predicting outcome. To improve decision making accurately predicting mortality and heart-failure hospitalization in patients with heart failure can be important for selecting patients with a poorer prognosis or nonresponders to current therapy, to improve decision making. MEDLINE/PubMed was searched for papers dealing with heart failure prediction models. To identify similar models on the basis of their variables hierarchical cluster analysis was performed. Meta-analysis was used to estimate the mean predictive value of the variables and models; meta-regression was used to find characteristics that explain variation in discriminating values between models. We identified 117 models in 55 papers. These models used 249 different variables. The strongest predictors were blood urea nitrogen and sodium. Four subgroups of models were identified. Mortality was most accurately predicted by prospective registry-type studies using a large number of clinical predictor variables. Mean C-statistic of all models was 0.66 ± 0.0005, with 0.71 ± 0.001, 0.68 ± 0.001 and 0.63 ± 0.001 for models predicting mortality, heart failure hospitalization, or both, respectively. There was no significant difference in discriminating value of models between patients with chronic and acute heart failure. Prediction of mortality and in particular heart failure hospitalization in patients with heart failure remains only moderately successful. The strongest predictors were blood urea nitrogen and sodium. The highest C-statistic values were achieved in a clinical setting, predicting short-term mortality with the use of models derived from prospective cohort/registry studies with a large number of predictor variables.

  13. Predictors of extubation success in acute ischemic stroke patients.

    PubMed

    Lioutas, Vasileios-Arsenios; Hanafy, Khalid A; Kumar, Sandeep

    2016-09-15

    Acute ischemic stroke (AIS) patients often undergo intubation and mechanical ventilation (MV). Prolonged intubation and MV have disadvantages and complications. Conventional extubation criteria based only on respiratory parameters are insufficient to guide extubation practices in stroke patients where capacity for airway protection is a major concern. To identify clinical and neuroanatomical markers of successful extubation in AIS patients requiring MV. Retrospective review of tertiary care hospital patient database from May 2009-November 2012 to identify consecutive patients with AIS intubated during hospitalization. We assessed the effect of age, sex, baseline National Institutes of Health Stroke Scale (NIHSS) score, level of consciousness, facial weakness, dysarthria, neglect, infarct location, dysphagia, respiratory parameters and history of pneumonia on successful extubation by hospital discharge using multivariate logistic regression analysis. 112 subjects met study criteria and were included in the analysis. Age and NIHSS scores (mean±standard deviation) were 74.5±16.1years and 19±9.8, respectively; 56% were women. In multivariate analysis, NIHSS score≤15 (Odds Ratio 4.6, 95% Confidence Interval 1.9-11.3, p<0.001) and absence of dysarthria prior to intubation (Odds Ratio 3.0, 95% Confidence interval 1.1-8.3, p=0.04) were independently associated with successful extubation. Conventional respiratory parameters had no effect on extubation success in this cohort. Milder stroke and absence of dysarthria prior to intubation were independently associated with extubation success. Our findings could help inform extubation practices in patients with AIS though prospective validation is necessary. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Serum Irisin Predicts Mortality Risk in Acute Heart Failure Patients.

    PubMed

    Shen, Shutong; Gao, Rongrong; Bei, Yihua; Li, Jin; Zhang, Haifeng; Zhou, Yanli; Yao, Wenming; Xu, Dongjie; Zhou, Fang; Jin, Mengchao; Wei, Siqi; Wang, Kai; Xu, Xuejuan; Li, Yongqin; Xiao, Junjie; Li, Xinli

    2017-01-01

    Irisin is a peptide hormone cleaved from a plasma membrane protein fibronectin type III domain containing protein 5 (FNDC5). Emerging studies have indicated association between serum irisin and many major chronic diseases including cardiovascular diseases. However, the role of serum irisin as a predictor for mortality risk in acute heart failure (AHF) patients is not clear. AHF patients were enrolled and serum was collected at the admission and all patients were followed up for 1 year. Enzyme-linked immunosorbent assay was used to measure serum irisin levels. To explore predictors for AHF mortality, the univariate and multivariate logistic regression analysis, and receiver-operator characteristic (ROC) curve analysis were used. To determine the role of serum irisin levels in predicting survival, Kaplan-Meier survival analysis was used. In this study, 161 AHF patients were enrolled and serum irisin level was found to be significantly higher in patients deceased in 1-year follow-up. The univariate logistic regression analysis identified 18 variables associated with all-cause mortality in AHF patients, while the multivariate logistic regression analysis identified 2 variables namely blood urea nitrogen and serum irisin. ROC curve analysis indicated that blood urea nitrogen and the most commonly used biomarker, NT-pro-BNP, displayed poor prognostic value for AHF (AUCs ≤ 0.700) compared to serum irisin (AUC = 0.753). Kaplan-Meier survival analysis demonstrated that AHF patients with higher serum irisin had significantly higher mortality (P<0.001). Collectively, our study identified serum irisin as a predictive biomarker for 1-year all-cause mortality in AHF patients though large multicenter studies are highly needed. © 2017 The Author(s). Published by S. Karger AG, Basel.

  15. Predicting oligonucleotide-directed mutagenesis failures in protein engineering

    PubMed Central

    Wassman, Christopher D.; Tam, Phillip Y.; Lathrop, Richard H.; Weiss, Gregory A.

    2004-01-01

    Protein engineering uses oligonucleotide-directed mutagenesis to modify DNA sequences through a two-step process of hybridization and enzymatic synthesis. Inefficient reactions confound attempts to introduce mutations, especially for the construction of vast combinatorial protein libraries. This paper applied computational approaches to the problem of inefficient mutagenesis. Several results implicated oligonucleotide annealing to non-target sites, termed ‘cross-hybridization’, as a significant contributor to mutagenesis reaction failures. Test oligonucleotides demonstrated control over reaction outcomes. A novel cross-hybridization score, quickly computable for any plasmid and oligonucleotide mixture, directly correlated with yields of deleterious mutagenesis side products. Cross-hybridization was confirmed conclusively by partial incorporation of an oligonucleotide at a predicted cross-hybridization site, and by modification of putative template secondary structure to control cross-hybridization. Even in low concentrations, cross-hybridizing species in mixtures poisoned reactions. These results provide a basis for improved mutagenesis efficiencies and increased diversities of cognate protein libraries. PMID:15585664

  16. Validation of the health ABC heart failure model for incident heart failure risk prediction: the Cardiovascular Health Study.

    PubMed

    Kalogeropoulos, Andreas; Psaty, Bruce M; Vasan, Ramachandran S; Georgiopoulou, Vasiliki; Smith, Andrew L; Smith, Nicholas L; Kritchevsky, Stephen B; Wilson, Peter W F; Newman, Anne B; Harris, Tamara B; Butler, Javed

    2010-07-01

    The recently developed and internally validated Health ABC HF model uses 9 routinely available clinical variables to determine incident heart failure risk. In this study, we sought to externally validate the Health ABC HF model. Observed 5-year incidence of heart failure, defined as first hospitalization for new-onset heart failure, was compared with 5-year risk estimates derived from the Health ABC HF model among participants without heart failure at baseline in the Cardiovascular Health Study. During follow-up, 400 of 5335 (7.5%) participants developed heart failure over 5 years versus 364 (6.8%) predicted by the Health ABC HF model (predicted-to-observed ratio, 0.90). Observed versus predicted 5-year heart failure probabilities were 3.2% versus 2.8%, 9.0% versus 7.0%, 15.9% versus 13.7%, and 24.6% versus 30.8% for the <5%, 5% to 10%, 10% to 20%, and >20% 5-year risk categories, respectively. The Hosmer-Lemeshow chi(2) was 14.72 (degrees of freedom, 10; P=0.14), and the C index was 0.74 (95% CI, 0.72 to 0.76). Calibration and discrimination demonstrated adequate performance across sex and race overall; however, risk was underestimated in white men, especially in the 5% to 10% risk category. Model performance was optimal when participants with normal left ventricular function at baseline were assessed separately. Performance was consistent across age groups. Analyses with death as a competing risk yielded similar results. The Health ABC HF model adequately predicted 5-year heart failure risk in a large community-based study, providing support for the external validity of the model. This tool may be used to identify individuals to whom to target heart failure prevention efforts.

  17. Preparation and Cluster Analysis of Data from the Industrial Production Process for Failure Prediction

    NASA Astrophysics Data System (ADS)

    Németh, Martin; Michaľčonok, German

    2016-12-01

    This article is devoted to the initial phase of data analysis of failure data from process control systems. Failure data can be used for example to detect weak spots in a production process, but also for failure prediction. To achieve these goals data mining techniques can be used. In this article, we propose a method to prepare and transform failure data from process control systems for application of data mining algorithms, especially cluster analysis.

  18. Accurate Prediction of Motor Failures by Application of Multi CBM Tools: A Case Study

    NASA Astrophysics Data System (ADS)

    Dutta, Rana; Singh, Veerendra Pratap; Dwivedi, Jai Prakash

    2017-05-01

    Motor failures are very difficult to predict accurately with a single condition-monitoring tool as both electrical and the mechanical systems are closely related. Electrical problem, like phase unbalance, stator winding insulation failures can, at times, lead to vibration problem and at the same time mechanical failures like bearing failure, leads to rotor eccentricity. In this case study of a 550 kW blower motor it has been shown that a rotor bar crack was detected by current signature analysis and vibration monitoring confirmed the same. In later months in a similar motor vibration monitoring predicted bearing failure and current signature analysis confirmed the same. In both the cases, after dismantling the motor, the predictions were found to be accurate. In this paper we will be discussing the accurate predictions of motor failures through use of multi condition monitoring tools with two case studies.

  19. Evaluation of noninvasive positive pressure ventilation after extubation from moderate positive end-expiratory pressure level in patients undergoing cardiovascular surgery: a prospective observational study.

    PubMed

    Suzuki, Takeshi; Kurazumi, Takuya; Toyonaga, Shinya; Masuda, Yuya; Morita, Yoshihisa; Masuda, Junichi; Kosugi, Shizuko; Katori, Nobuyuki; Morisaki, Hiroshi

    2014-01-01

    It remains to be clarified if the application of noninvasive positive pressure ventilation (NPPV) is effective after extubation in patients with hypoxemic respiratory failure who require the sufficient level of positive end-expiratory pressure (PEEP). This study was aimed at examining the effect and the safety of NPPV application following extubation in patients requiring moderate PEEP level for sufficient oxygenation after cardiovascular surgery. With institutional ethic committee approval, the patients ventilated invasively for over 48 h after cardiovascular surgery were enrolled in this study. The patients who failed the first spontaneous breathing trial (SBT) at 5 cmH2O of PEEP, but passed the second SBT at 8 cmH2O of PEEP, received NPPV immediately after extubation following our weaning protocol. Respiratory parameters (partial pressure of arterial oxygen tension to inspiratory oxygen fraction ratio: P/F ratio, respiratory ratio, and partial pressure of arterial carbon dioxide: PaCO2) 2 h after extubation were evaluated with those just before extubation as the primary outcome. The rate of re-intubation, the frequency of respiratory failure and intolerance of NPPV, the duration of NPPV, and the length of intensive care unit (ICU) stay were also recorded. While 51 postcardiovascular surgery patients were screened, 6 patients who met the criteria received NPPV after extubation. P/F ratio was increased significantly after extubation compared with that before extubation (325 ± 85 versus 245 ± 55 mmHg, p < 0.05). The other respiratory parameters did not change significantly. Re-intubation, respiratory failure, and intolerance of NPPV never occurred. The duration of NPPV and the length of ICU stay were 2.7 ± 0.7 (SD) and 7.5 (6 to 10) (interquartile range) days, respectively. While further investigation should be warranted, NPPV could be applied effectively and safely after extubation in patients requiring the moderate PEEP level after

  20. Residual paralysis at the time of tracheal extubation.

    PubMed

    Murphy, Glenn S; Szokol, Joseph W; Marymont, Jesse H; Franklin, Mark; Avram, Michael J; Vender, Jeffery S

    2005-06-01

    Respiratory and pharyngeal muscle function are impaired during minimal neuromuscular blockade. Tracheal extubation in the presence of residual paresis may contribute to adverse respiratory events. In this investigation, we assessed the incidence and severity of residual neuromuscular block at the time of tracheal extubation. One-hundred-twenty patients presenting for gynecologic or general surgical procedures were enrolled. Neuromuscular blockade was maintained with rocuronium (visual train-of-four [TOF] count of 2) and all subjects were reversed with neostigmine at a TOF count of 2-4. TOF ratios were quantified using acceleromyography immediately before tracheal extubation, after clinicians had determined that complete neuromuscular recovery had occurred using standard clinical criteria (5-s head lift or hand grip, eye opening on command, acceptable negative inspiratory force or vital capacity breath values) and peripheral nerve stimulation (no evidence of fade with TOF or tetanic stimulation). TOF ratios were measured again on arrival to the postanesthesia care unit. Immediately before tracheal extubation, the mean TOF ratio was 0.67 +/- 0.2; among the 120 patients, 70 (58%) had a TOF ratio <0.7 and 105 (88%) had a TOF ratio <0.9. Significantly fewer patients had TOF ratios <0.7 (9 subjects, 8%) and <0.9 (38 subjects, 32%) in the postanesthesia care unit compared with the operating room (P < 0.001). Our results suggest that complete recovery from neuromuscular blockade is rarely present at the time of tracheal extubation.

  1. Predictive Surgical Reasons for Failure After Coracoid Process Transfers

    PubMed Central

    Gasbarro, Gregory; Giugale, Juan Marcelo; Walch, Gilles; Lin, Albert

    2016-01-01

    Background: Recurrent anterior shoulder instability after coracoid process transfers may be caused by trauma, sports injury, or technical failure of the index procedure. Surgical techniques vary with regard to graft orientation and positioning and number of screws utilized for fixation. Purpose: To identify surgical and patient-related factors associated with failure, defined as the need for revision surgery. We hypothesized that failures will occur more commonly with single-screw fixation and graft malposition. Study Design: Case series; Level of evidence, 4. Methods: Eighty-three patients (mean age, 24 years) who underwent an Eden-Hybinette operation as a revision procedure for recurrent anterior instability after primary coracoid process transfer between 1977 and 2010 were retrospectively reviewed. Preoperative medical records were queried for demographic data, failure event, and physical examination. Two fellowship-trained shoulder surgeons reviewed radiographs to identify for graft positioning, nonunion, and hardware failure. Descriptive analysis was used to assess reasons for failure. Results: Seventy-five percent of patients sustained a redislocation event after primary coracoid process transfer. Revisions were performed on average 50.3 months after the index procedure, most commonly on males, with two-thirds of recurrent instability occurring during sports. Among all patients, single-screw methods for fixation and inferior graft malposition during index bone block transfer were the most common. Hardware failure and graft nonunion were more frequent with the single-screw technique. Conclusion: In our series, recurrent anterior shoulder instability after primary coracoid process transfer was more likely to occur during sports in young, male patients. The most common technical errors leading to revision were placing the graft inferior to the 5-o’clock position on the glenoid face or relying on single-screw fixation. PMID:28210649

  2. Predicting failure: acoustic emission of berlinite under compression.

    PubMed

    Nataf, Guillaume F; Castillo-Villa, Pedro O; Sellappan, Pathikumar; Kriven, Waltraud M; Vives, Eduard; Planes, Antoni; Salje, Ekhard K H

    2014-07-09

    Acoustic emission has been measured and statistical characteristics analyzed during the stress-induced collapse of porous berlinite, AlPO4, containing up to 50 vol% porosity. Stress collapse occurs in a series of individual events (avalanches), and each avalanche leads to a jerk in sample compression with corresponding acoustic emission (AE) signals. The distribution of AE avalanche energies can be approximately described by a power law p(E)dE = E(-ε)dE (ε ~ 1.8) over a large stress interval. We observed several collapse mechanisms whereby less porous minerals show the superposition of independent jerks, which were not related to the major collapse at the failure stress. In highly porous berlinite (40% and 50%) an increase of energy emission occurred near the failure point. In contrast, the less porous samples did not show such an increase in energy emission. Instead, in the near vicinity of the main failure point they showed a reduction in the energy exponent to ~ 1.4, which is consistent with the value reported for compressed porous systems displaying critical behavior. This suggests that a critical avalanche regime with a lack of precursor events occurs. In this case, all preceding large events were 'false alarms' and unrelated to the main failure event. Our results identify a method to use pico-seismicity detection of foreshocks to warn of mine collapse before the main failure (the collapse) occurs, which can be applied to highly porous materials only.

  3. Nasal nitric oxide in infants before and after extubation.

    PubMed

    Chang, Chun-Cheng; Lien, Shao-Hung; Liu, Tao-Yuan; Hua, Yi-Ming; Lee, Chuen-Ming; Yuh, Yeong-Seng

    2008-11-01

    The endogenous production of nitric oxide (NO) in the upper airways is known to be high, but reports of the exact level vary, especially in newborn infants. Currently there is still no standard methodology for nasal NO measurements in neonates. In this study, we compared the levels of NO from the nasal cavity, and from the lower respiratory tracts in intubated infants together with the differences in nasal NO before and after extubation. A total of 35 intubated infants were enrolled in the study. The sampling was conducted with a fast-response chemoluminescence analyzer using the on-line tidal breathing techniques. The levels of NO in the nasal cavity were sampled using two different methods, namely nasal catheterization (Group 1), and nasal occlusion (Group 2). In both groups, the NO levels in the nasal cavity were found to be significantly higher than in the lower airway (P < 0.001). After extubation, the concentration of nasal NO in Group 1 was found to be significantly lower than before extubation (P < 0.05). There was no difference found between the levels of nasal NO in Group 2 before and after extubation (P = 0.95). Generally speaking, the concentrations of nasal NO in Group 2 were significantly higher than in Group 1 after extubation (P < 0.05). For the sample that used nasal occlusion, the nasal NO levels were more stable before and after extubation and the concentration was not affected by the breathing pattern or crying. The infants were more comfortable as well. We therefore conclude that nasal occlusion is a better method for measuring the levels of nasal NO in infants and neonates. (c) 2008 Wiley-Liss, Inc.

  4. [Early extubation with caudal morphine after pediatric heart surgery].

    PubMed

    Figueira Moure, A; Pensado Castiñeiras, A; Vázquez Fidalgo, A; Fernández Goti, C; Diéguez Fernández, M; Sanduende Otero, Y; Sánchez Galindo, A; Ramil Fraga, C; Portela Torrón, F; Zavanella Botta, C

    2003-02-01

    To analyze the viability of immediate extubation of children after corrective surgery for congenital heart defects with extracorporeal membrane oxygenation using an anesthetic technique involving caudal morphine, and to study the effect on length of stay in the pediatric intensive care unit (PICU) or elsewhere in the hospital. Twenty-nine ASA I-II patients without coagulation alterations undergoing surgery to correct simple heart defects were selected for extubation after surgery. Anesthesia was provided with with sevoflurane, midazolam, rocuronium, fentanil (maximum dose 10 micrograms/Kg) and a bolus of caudal morphine (50-60 micrograms/Kg) after anesthetic induction. Patient characteristics, type of surgery, times of extracorporeal circulation and of ischemia, arterial blood gases upon arrival in the PICU, postoperative complications and quality of analgesia were the variables analyzed. We also compared length of stay in the PICU and hospital for the study group and for a historical control group of 23 patients who had no received caudal morphine or been selected for early extubation. All patients were extubated satisfactorily in the operating room. None required reintubation or reoperation. Postoperative pain was controlled with metamizol alone for 79.3%. No episodes of respiratory depression or neurological complications were observed. PICU and hospital stays were significantly shorter in the study group than in the control group. Of patients undergoing simple corrective heart surgery with extracorporeal membrane oxygenation immediate extubation did not increase postoperative morbimortality and shortened the hospital stay. A single dose of caudal morphine provided optimum conditions for extubation and good control of postoperative pain. Strict measures must be taken, however, to avoid postpuncture bleeding.

  5. Prediction of late failure after medical abortion from serial beta-hCG measurements and ultrasonography.

    PubMed

    Rørbye, C; Nørgaard, M; Nilas, L

    2004-01-01

    Surgical treatment of failed medical abortion may be performed several weeks after initiation of the abortion. There are no recognized methods for early identification of these late failures. We assessed the prognostic values of beta-hCG and ultrasonography in predicting late failure after medical abortion. A total of 694 consecutive women with gestational age (GA) <63 days were followed up with beta-hCG measurements initially on the day of treatment and on day 8 and day 15, after the medically induced abortion with mifepristone and gemeprost. Measurement of the endometrial thickness by ultrasonography was performed on day 15 after induction of medical abortion. Failures diagnosed after day 15 and within 15 weeks were identified and classified as late failures. All interventions in this group were due to bleeding problems. The predictive values of different absolute and relative beta-hCG levels and different endometrial thickness were analysed. Of all failures in the study period, 65% (32) were diagnosed after the 2 week follow-up, and categorized as late failures. The absolute and the relative beta-hCG values on days 8 and 15 as well as the endometrial thickness on day 15 were greater among late failures than successes. Used as a predictive test, the positive predictive values of these variables were low. Neither beta-hCG nor endometrial thickness can be used clinically as diagnostic tests in predicting late failure after medical abortion.

  6. Association Rule-based Predictive Model for Machine Failure in Industrial Internet of Things

    NASA Astrophysics Data System (ADS)

    Kwon, Jung-Hyok; Lee, Sol-Bee; Park, Jaehoon; Kim, Eui-Jik

    2017-09-01

    This paper proposes an association rule-based predictive model for machine failure in industrial Internet of things (IIoT), which can accurately predict the machine failure in real manufacturing environment by investigating the relationship between the cause and type of machine failure. To develop the predictive model, we consider three major steps: 1) binarization, 2) rule creation, 3) visualization. The binarization step translates item values in a dataset into one or zero, then the rule creation step creates association rules as IF-THEN structures using the Lattice model and Apriori algorithm. Finally, the created rules are visualized in various ways for users’ understanding. An experimental implementation was conducted using R Studio version 3.3.2. The results show that the proposed predictive model realistically predicts machine failure based on association rules.

  7. Rational Temporal Predictions Can Underlie Apparent Failures to Delay Gratification

    ERIC Educational Resources Information Center

    McGuire, Joseph T.; Kable, Joseph W.

    2013-01-01

    An important category of seemingly maladaptive decisions involves failure to postpone gratification. A person pursuing a desirable long-run outcome may abandon it in favor of a short-run alternative that has been available all along. Here we present a theoretical framework in which this seemingly irrational behavior emerges from stable preferences…

  8. Effect of various approximations on predicted progressive failure in plain weave composites

    NASA Technical Reports Server (NTRS)

    Whitcomb, John; Srirengan, Kanthikannan

    1995-01-01

    Three-dimensional finite element analysis was used to simulate progressive failure of a plain weave composite subjected to in-plane extension. The loading was parallel to one of the tow directions. The effects of various characteristics of the finite element model on predicted behavior were examined. The predicted behavior was found to be sensitive to quadrature order, mesh refinement, and the material degradation model. Also the sensitivity of the predictions to the tow waviness was studied. The predicted strength decreased considerably with increased waviness. More numerical studies and comparisons with experimental data are needed to establish reliable guidelines for accurate progressive failure prediction.

  9. Predicting Time Series Outputs and Time-to-Failure for an Aircraft Controller Using Bayesian Modeling

    NASA Technical Reports Server (NTRS)

    He, Yuning

    2015-01-01

    Safety of unmanned aerial systems (UAS) is paramount, but the large number of dynamically changing controller parameters makes it hard to determine if the system is currently stable, and the time before loss of control if not. We propose a hierarchical statistical model using Treed Gaussian Processes to predict (i) whether a flight will be stable (success) or become unstable (failure), (ii) the time-to-failure if unstable, and (iii) time series outputs for flight variables. We first classify the current flight input into success or failure types, and then use separate models for each class to predict the time-to-failure and time series outputs. As different inputs may cause failures at different times, we have to model variable length output curves. We use a basis representation for curves and learn the mappings from input to basis coefficients. We demonstrate the effectiveness of our prediction methods on a NASA neuro-adaptive flight control system.

  10. Sedation with a remifentanil infusion to facilitate rapid awakening and tracheal extubation in an infant with a potentially compromised airway

    PubMed Central

    Naples, Jeffrey; Hall, Mark W; Tobias, Joseph D

    2016-01-01

    Sedation is generally required during endotracheal intubation and mechanical ventilation in infants and children. While there are many options for the provision of sedation, the most commonly used agents such as midazolam and fentanyl demonstrate a context-sensitive half-life, which may result in a prolonged effect when these agents are discontinued following a continuous infusion. We present a 20-month-old infant who required endotracheal intubation due to respiratory failure following seizures. At the referring hospital, multiple laryngoscopies were performed with the potential for airway trauma. To maximize rapid awakening and optimize respiratory function surrounding tracheal extubation, sedation was transitioned from fentanyl and midazolam to remifentanil for 18–24 hours prior to tracheal extubation. The unique pharmacokinetics of remifentanil are presented in this study, its use in this clinical scenario is discussed, and its potential applications in the pediatric intensive care unit setting are reviewed. PMID:27826208

  11. Method of Testing and Predicting Failures of Electronic Mechanical Systems

    NASA Technical Reports Server (NTRS)

    Iverson, David L.; Patterson-Hine, Frances A.

    1996-01-01

    A method employing a knowledge base of human expertise comprising a reliability model analysis implemented for diagnostic routines is disclosed. The reliability analysis comprises digraph models that determine target events created by hardware failures human actions, and other factors affecting the system operation. The reliability analysis contains a wealth of human expertise information that is used to build automatic diagnostic routines and which provides a knowledge base that can be used to solve other artificial intelligence problems.

  12. Prediction Score for Antimony Treatment Failure in Patients with Ulcerative Leishmaniasis Lesions

    PubMed Central

    Dujardin, Jean Claude; Llanos-Cuentas, Alejandro; Chappuis, François; Zimic, Mirko

    2012-01-01

    Background Increased rates for failure in leishmaniasis antimony treatment have been recently recognized worldwide. Although several risk factors have been identified there is no clinical score to predict antimony therapy failure of cutaneous leishmaniasis. Methods A case control study was conducted in Peru from 2001 to 2004. 171 patients were treated with pentavalent antimony and followed up to at least 6 months to determine cure or failure. Only patients with ulcerative cutaneous leishmaniasis (N = 87) were considered for data analysis. Epidemiological, demographical, clinical and laboratory data were analyzed to identify risk factors for treatment failure. Two prognostic scores for antimonial treatment failure were tested for sensitivity and specificity to predict antimony therapy failure by comparison with treatment outcome. Results Among 87 antimony-treated patients, 18 (21%) failed the treatment and 69 (79%) were cured. A novel risk factor for treatment failure was identified: presence of concomitant distant lesions. Patients presenting concomitant-distant lesions showed a 30.5-fold increase in the risk of treatment failure compared to other patients. The best prognostic score for antimonial treatment failure showed a sensitivity of 77.78% and specificity of 95.52% to predict antimony therapy failure. Conclusions A prognostic score including a novel risk factor was able to predict antimonial treatment failure in cutaneous leishmaniasis with high specificity and sensitivity. This prognostic score presents practical advantages as it relies on clinical and epidemiological characteristics, easily obtained by physicians or health workers, and makes it a promising clinical tool that needs to be validated before their use for developing countries. PMID:22720098

  13. Microstructurally Based Prediction of High Strain Failure Modes in Crystalline Solids

    DTIC Science & Technology

    2016-07-05

    methodologies, and in-situ experiments to predict how combinations of ductile failure modes initiate and evolve, at different physical scales, to complete...different interrelated physical mechanisms, such as a myriad of representative dislocation-density 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE...and in-situ experiments to predict how combinations of ductile failure modes initiate and evolve, at different physical scales, to complete rupture in

  14. Developing a predictive risk model for first-line antiretroviral therapy failure in South Africa

    PubMed Central

    Rohr, Julia K; Ive, Prudence; Horsburgh, C Robert; Berhanu, Rebecca; Shearer, Kate; Maskew, Mhairi; Long, Lawrence; Sanne, Ian; Bassett, Jean; Ebrahim, Osman; Fox, Matthew P

    2016-01-01

    Introduction A substantial number of patients with HIV in South Africa have failed first-line antiretroviral therapy (ART). Although individual predictors of first-line ART failure have been identified, few studies in resource-limited settings have been large enough for predictive modelling. Understanding the absolute risk of first-line failure is useful for patient monitoring and for effectively targeting limited resources for second-line ART. We developed a predictive model to identify patients at the greatest risk of virologic failure on first-line ART, and to estimate the proportion of patients needing second-line ART over five years on treatment. Methods A cohort of patients aged ≥18 years from nine South African HIV clinics on first-line ART for at least six months were included. Viral load measurements and baseline predictors were obtained from medical records. We used stepwise selection of predictors in accelerated failure-time models to predict virologic failure on first-line ART (two consecutive viral load levels >1000 copies/mL). Multiple imputations were used to assign missing baseline variables. The final model was selected using internal-external cross-validation maximizing model calibration at five years on ART, and model discrimination, measured using Harrell's C-statistic. Model covariates were used to create a predictive score for risk group of ART failure. Results A total of 72,181 patients were included in the analysis, with an average of 21.5 months (IQR: 8.8–41.5) of follow-up time on first-line ART. The final predictive model had a Weibull distribution and the final predictors of virologic failure were men of all ages, young women, nevirapine use in first-line regimen, low baseline CD4 count, high mean corpuscular volume, low haemoglobin, history of TB and missed visits during the first six months on ART. About 24.4% of patients in the highest quintile and 9.4% of patients in the lowest quintile of risk were predicted to experience

  15. Development of predisposition, injury, response, organ failure model for predicting acute kidney injury in acute on chronic liver failure.

    PubMed

    Maiwall, Rakhi; Sarin, Shiv Kumar; Kumar, Suman; Jain, Priyanka; Kumar, Guresh; Bhadoria, Ajeet Singh; Moreau, Richard; Kedarisetty, Chandan Kumar; Abbas, Zaigham; Amarapurkar, Deepak; Bhardwaj, Ankit; Bihari, Chhagan; Butt, Amna Subhan; Chan, Albert; Chawla, Yogesh Kumar; Chowdhury, Ashok; Dhiman, RadhaKrishan; Dokmeci, Abdul Kadir; Ghazinyan, Hasmik; Hamid, Saeed Sadiq; Kim, Dong Joon; Komolmit, Piyawat; Lau, George K; Lee, Guan Huei; Lesmana, Laurentius A; Jamwal, Kapil; Mamun-Al-Mahtab; Mathur, Rajendra Prasad; Nayak, Suman Lata; Ning, Qin; Pamecha, Viniyendra; Alcantara-Payawal, Diana; Rastogi, Archana; Rahman, Salimur; Rela, Mohamed; Saraswat, Vivek A; Shah, Samir; Shiha, Gamal; Sharma, Barjesh Chander; Sharma, Manoj Kumar; Sharma, Kapil; Tan, Soek Siam; Chandel, Shivendra Singh; Vashishtha, Chitranshu; Wani, Zeeshan A; Yuen, Man-Fung; Yokosuka, Osamu; Duseja, Ajay; Jafri, Wasim; Devarbhavi, Harshad; Eapen, C E; Goel, Ashish; Sood, Ajit; Ji, Jia; Duan, Z; Chen, Y

    2017-10-01

    There is limited data on predictors of acute kidney injury in acute on chronic liver failure. We developed a PIRO model (Predisposition, Injury, Response, Organ failure) for predicting acute kidney injury in a multicentric cohort of acute on chronic liver failure patients. Data of 2360 patients from APASL-ACLF Research Consortium (AARC) was analysed. Multivariate logistic regression model (PIRO score) was developed from a derivation cohort (n=1363) which was validated in another prospective multicentric cohort of acute on chronic liver failure patients (n=997). Factors significant for P component were serum creatinine[(≥2 mg/dL)OR 4.52, 95% CI (3.67-5.30)], bilirubin [(<12 mg/dL,OR 1) vs (12-30 mg/dL,OR 1.45, 95% 1.1-2.63) vs (≥30 mg/dL,OR 2.6, 95% CI 1.3-5.2)], serum potassium [(<3 mmol/LOR-1) vs (3-4.9 mmol/L,OR 2.7, 95% CI 1.05-1.97) vs (≥5 mmol/L,OR 4.34, 95% CI 1.67-11.3)] and blood urea (OR 3.73, 95% CI 2.5-5.5); for I component nephrotoxic medications (OR-9.86, 95% CI 3.2-30.8); for R component,Systemic Inflammatory Response Syndrome,(OR-2.14, 95% CI 1.4-3.3); for O component, Circulatory failure (OR-3.5, 95% CI 2.2-5.5). The PIRO score predicted acute kidney injury with C-index of 0.95 and 0.96 in the derivation and validation cohort. The increasing PIRO score was also associated with mortality (P<.001) in both the derivation and validation cohorts. The PIRO model identifies and stratifies acute on chronic liver failure patients at risk of developing acute kidney injury. It reliably predicts mortality in these patients, underscoring the prognostic significance of acute kidney injury in patients with acute on chronic liver failure. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Real-time forecasting and predictability of catastrophic failure events: from rock failure to volcanoes and earthquakes

    NASA Astrophysics Data System (ADS)

    Main, I. G.; Bell, A. F.; Naylor, M.; Atkinson, M.; Filguera, R.; Meredith, P. G.; Brantut, N.

    2012-12-01

    Accurate prediction of catastrophic brittle failure in rocks and in the Earth presents a significant challenge on theoretical and practical grounds. The governing equations are not known precisely, but are known to produce highly non-linear behavior similar to those of near-critical dynamical systems, with a large and irreducible stochastic component due to material heterogeneity. In a laboratory setting mechanical, hydraulic and rock physical properties are known to change in systematic ways prior to catastrophic failure, often with significant non-Gaussian fluctuations about the mean signal at a given time, for example in the rate of remotely-sensed acoustic emissions. The effectiveness of such signals in real-time forecasting has never been tested before in a controlled laboratory setting, and previous work has often been qualitative in nature, and subject to retrospective selection bias, though it has often been invoked as a basis in forecasting natural hazard events such as volcanoes and earthquakes. Here we describe a collaborative experiment in real-time data assimilation to explore the limits of predictability of rock failure in a best-case scenario. Data are streamed from a remote rock deformation laboratory to a user-friendly portal, where several proposed physical/stochastic models can be analysed in parallel in real time, using a variety of statistical fitting techniques, including least squares regression, maximum likelihood fitting, Markov-chain Monte-Carlo and Bayesian analysis. The results are posted and regularly updated on the web site prior to catastrophic failure, to ensure a true and and verifiable prospective test of forecasting power. Preliminary tests on synthetic data with known non-Gaussian statistics shows how forecasting power is likely to evolve in the live experiments. In general the predicted failure time does converge on the real failure time, illustrating the bias associated with the 'benefit of hindsight' in retrospective analyses

  17. Multiscale Model Predicts Tissue-Level Failure From Collagen Fiber-Level Damage

    PubMed Central

    Hadi, Mohammad F.; Sander, Edward A.; Barocas, Victor H.

    2013-01-01

    Excessive tissue-level forces communicated to the microstructure and extracellular matrix of soft tissues can lead to damage and failure through poorly understood physical processes that are multiscale in nature. In this work, we propose a multiscale mechanical model for the failure of collagenous soft tissues that incorporates spatial heterogeneity in the microstructure and links the failure of discrete collagen fibers to the material response of the tissue. The model, which is based on experimental failure data derived from different collagen gel geometries, was able to predict the mechanical response and failure of type I collagen gels, and it demonstrated that a fiber-based rule (at the micrometer scale) for discrete failure can strongly shape the macroscale failure response of the gel (at the millimeter scale). The model may be a useful tool in predicting the macroscale failure conditions for soft tissues and engineered tissue analogs. In addition, the multiscale model provides a framework for the study of failure in complex fiber-based mechanical systems in general. PMID:22938372

  18. A new statistical methodology predicting chip failure probability considering electromigration

    NASA Astrophysics Data System (ADS)

    Sun, Ted

    In this research thesis, we present a new approach to analyze chip reliability subject to electromigration (EM) whose fundamental causes and EM phenomenon happened in different materials are presented in this thesis. This new approach utilizes the statistical nature of EM failure in order to assess overall EM risk. It includes within-die temperature variations from the chip's temperature map extracted by an Electronic Design Automation (EDA) tool to estimate the failure probability of a design. Both the power estimation and thermal analysis are performed in the EDA flow. We first used the traditional EM approach to analyze the design with a single temperature across the entire chip that involves 6 metal and 5 via layers. Next, we used the same traditional approach but with a realistic temperature map. The traditional EM analysis approach and that coupled with a temperature map and the comparison between the results of considering and not considering temperature map are presented in in this research. A comparison between these two results confirms that using a temperature map yields a less pessimistic estimation of the chip's EM risk. Finally, we employed the statistical methodology we developed considering a temperature map and different use-condition voltages and frequencies to estimate the overall failure probability of the chip. The statistical model established considers the scaling work with the usage of traditional Black equation and four major conditions. The statistical result comparisons are within our expectations. The results of this statistical analysis confirm that the chip level failure probability is higher i) at higher use-condition frequencies for all use-condition voltages, and ii) when a single temperature instead of a temperature map across the chip is considered. In this thesis, I start with an overall review on current design types, common flows, and necessary verifications and reliability checking steps used in this IC design industry

  19. Peridynamics for failure and residual strength prediction of fiber-reinforced composites

    NASA Astrophysics Data System (ADS)

    Colavito, Kyle

    Peridynamics is a reformulation of classical continuum mechanics that utilizes integral equations in place of partial differential equations to remove the difficulty in handling discontinuities, such as cracks or interfaces, within a body. Damage is included within the constitutive model; initiation and propagation can occur without resorting to special crack growth criteria necessary in other commonly utilized approaches. Predicting damage and residual strengths of composite materials involves capturing complex, distinct and progressive failure modes. The peridynamic laminate theory correctly predicts the load redistribution in general laminate layups in the presence of complex failure modes through the use of multiple interaction types. This study presents two approaches to obtain the critical peridynamic failure parameters necessary to capture the residual strength of a composite structure. The validity of both approaches is first demonstrated by considering the residual strength of isotropic materials. The peridynamic theory is used to predict the crack growth and final failure load in both a diagonally loaded square plate with a center crack, as well as a four-point shear specimen subjected to asymmetric loading. This study also establishes the validity of each approach by considering composite laminate specimens in which each failure mode is isolated. Finally, the failure loads and final failure modes are predicted in a laminate with various hole diameters subjected to tensile and compressive loads.

  20. Efficacy of resistin and leptin in predicting persistent organ failure in patients with acute pancreatitis.

    PubMed

    Yu, Pengfei; Wang, Shiqi; Qiu, Zhaoyan; Bai, Bin; Zhao, Zhanwei; Hao, Yiming; Wang, Qian; Guo, Min; Feng, Xiangying; Zhu, Junjie; Feng, Quanxin; Zhao, Qingchuan

    To investigate the accuracy of resistin, leptin and adiponectin levels in predicting persistent organ failure in patients with acute pancreatitis (AP). Data from 90 consecutive patients admitted to our hospital for AP were retrospectively collected from an ongoing prospective cohort study. The levels of adiponectin, leptin and resistin were measured and compared between patients with and without persistent organ failure. The accuracy of the adipokines in predicting persistent organ failure were compared with the patients' Acute Physiology and Chronic Health Evaluation II (APACHE-II) score, and were separately investigated in overweight and non-overweight groups. Persistent organ failure occurred in 26.7% of the patients. The levels of resistin were significantly increased in AP patients with persistent organ failure, in both the overweight and the non-overweight subgroups. Resistin and APACHE-II score predicted persistent organ failure with comparable areas under the curve (AUC) of 0.72 and 0.75, respectively (p = 0.66). Resistin demonstrated similar accuracy with the APACHE-II score in predicting persistent organ failure in the overweight (0.69 vs. 0.66, p = 0.82) and non-overweight (0.76 vs. 0.87, p = 0.39) subgroups. There was no correlation between adiponectin and persistent organ failure, but a weak correlation between leptin and persistent organ failure was demonstrated. Resistin and leptin levels, rather than adiponectin, correlate with persistent organ failure in patients with AP. Copyright © 2016 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  1. [Predictive factors for readmission in heart failure patients].

    PubMed

    Galofré, Nuria; San Vicente, Ludmila; González, Josep Anton; Planas, Francesc; Vila, Joaquim; Grau, Jordi

    2005-03-05

    Heart failure (HF) is a prevalent and increasing disease and represents one of the main causes of hospital admission. It is associated with an important morbi-mortality and a high rate of readmission. The objective of this study was to know the clinical characteristics of admitted patients with HF and to detect any valuable prognosis factors. Prospective study of admitted HF patients between May'99 and May'00. Readmission rate was evaluated six months later. 204 patients were included with an average age of 78 (9.9) years. 66% were women. Diabetes mellitus (DM) (36.4%) and chronic obstructive pulmonary disease (COPD) (23.4%) were the most outstanding associated pathologies. Ischemic heart disease (IHD) was the most frequent etiology in 33.4% cases. Mean time of admission was 10 days. 34% patients had systolic dysfunction (SD). Men with IHD presented a higher rate of SD (p < 0.001). Mortality was 12.4%, especially in COPD patients (p < 0.011). IECAs were prescribed in 71.2% in the SD group. Readmission rate at 6 months was about 43%. Patients with renal failure (p < 0.04) and those with a more impaired functional class (p < 0.02) displayed a higher readmission rate. Several clinical factors determine the morbi-mortality and prognosis including an older age, associated comorbility, type of cardiopathy and presence of systolic dysfunction. All these factors are detected at the time of hospital admission.

  2. Validation of the Denver Emergency Department Trauma Organ Failure Score to Predict Post-Injury Multiple Organ Failure

    PubMed Central

    Vogel, Jody A; Newgard, Craig D; Holmes, James F; Diercks, Deborah B; Arens, Ann M; Boatright, Dowin H; Bueso, Antonio; Gaona, Samuel D; Gee, Kaitlin Z; Nelson, Anna; Voros, Jeremy J; Moore, Ernest E; Colwell, Christopher B; Haukoos, Jason S

    2015-01-01

    Background Early recognition of trauma patients at risk for multiple organ failure (MOF) is important to reduce the morbidity and mortality associated with MOF. The objective of the study was to externally validate the Denver Emergency Department (ED) Trauma Organ Failure (TOF) Score, a six-item instrument that includes age, intubation, hematocrit, systolic blood pressure, blood urea nitrogen, and white blood cell count, which was designed to predict the development of MOF within seven days of hospitalization. Study Design Prospective multi-center study of adult trauma patients between November, 2011 and March, 2013. The primary outcome was development of MOF within seven days of hospitalization, assessed using the Sequential Organ Failure Assessment Score. Hierarchical logistic regression analysis was performed to determine associations between Denver ED TOF Score and MOF. Discrimination was assessed and quantified using a receiver operating characteristics (ROC) curve. The predictive accuracy of the Denver ED TOF score was compared to attending emergency physician estimation of the likelihood of MOF. Results We included 2,072 patients with a median age of 46 (IQR 30-61) years and 68% male. The median injury severity score was 9 (IQR 5-17) and 88% of patients had blunt mechanisms. Among participants, 1,024 patients (49%) were admitted to the intensive care unit, and 77 (4%) died. MOF occurred in 120 (6%; 95% CI: 5%-7%) patients and of these, 37 (31%; 95% CI: 23%-40%) died. The area under the ROC curve for the Denver ED TOF Score prediction of MOF was 0.89 (95% CI 0.86-0.91) and for physician estimation of the likelihood of MOF was 0.78 (95% CI 0.73-0.83). Conclusions The Denver ED TOF Score predicts the development of MOF within seven days of hospitalization. Its predictive accuracy outperformed attending emergency physician estimation of the risk of MOF. PMID:26597706

  3. Predicting renal graft failure using multivariate longitudinal profiles.

    PubMed

    Fieuws, Steffen; Verbeke, Geert; Maes, Bart; Vanrenterghem, Yves

    2008-07-01

    Patients who have undergone renal transplantation are monitored longitudinally at irregular time intervals over 10 years or more. This yields a set of biochemical and physiological markers containing valuable information to anticipate a failure of the graft. A general linear, generalized linear, or nonlinear mixed model is used to describe the longitudinal profile of each marker. To account for the correlation between markers, the univariate mixed models are combined into a multivariate mixed model (MMM) by specifying a joint distribution for the random effects. Due to the high number of markers, a pairwise modeling strategy, where all possible pairs of bivariate mixed models are fitted, is used to obtain parameter estimates for the MMM. These estimates are used in a Bayes rule to obtain, at each point in time, the prognosis for long-term success of the transplant. It is shown that allowing the markers to be correlated can improve this prognosis.

  4. Noninvasive positive pressure ventilation after extubation: features and outcomes in clinical practice

    PubMed Central

    Yamauchi, Liria Yuri; Figueiroa, Maise; da Silveira, Leda Tomiko Yamada; Travaglia, Teresa Cristina Francischetto; Bernardes, Sidnei; Fu, Carolina

    2015-01-01

    Objective To describe postextubation noninvasive positive pressure ventilation use in intensive care unit clinical practice and to identify factors associated with noninvasive positive pressure ventilation failure. Methods This prospective cohort study included patients aged ≥ 18 years consecutively admitted to the intensive care unit who required noninvasive positive pressure ventilation within 48 hours of extubation. The primary outcome was noninvasive positive pressure ventilation failure. Results We included 174 patients in the study. The overall noninvasive positive pressure ventilation use rate was 15%. Among the patients who used noninvasive positive pressure ventilation, 44% used it after extubation. The failure rate of noninvasive positive pressure ventilation was 34%. The overall mean ± SD age was 56 ± 18 years, and 55% of participants were male. Demographics; baseline pH, PaCO2 and HCO3; and type of equipment used were similar between groups. All of the noninvasive positive pressure ventilation final parameters were higher in the noninvasive positive pressure ventilation failure group [inspiratory positive airway pressure: 15.0 versus 13.7cmH2O (p = 0.015), expiratory positive airway pressure: 10.0 versus 8.9cmH2O (p = 0.027), and FiO2: 41 versus 33% (p = 0.014)]. The mean intensive care unit length of stay was longer (24 versus 13 days), p < 0.001, and the intensive care unit mortality rate was higher (55 versus 10%), p < 0.001 in the noninvasive positive pressure ventilation failure group. After fitting, the logistic regression model allowed us to state that patients with inspiratory positive airway pressure ≥ 13.5cmH2O on the last day of noninvasive positive pressure ventilation support are three times more likely to experience noninvasive positive pressure ventilation failure compared with individuals with inspiratory positive airway pressure < 13.5 (OR = 3.02, 95%CI = 1.01 - 10.52, p value = 0.040). Conclusion The noninvasive positive pressure

  5. Multipulse laser-induced failure prediction for Mo metal mirrors

    NASA Astrophysics Data System (ADS)

    Becker, Michael F.; Ma, Chun C.; Walser, Rodger M.

    1991-06-01

    In combination with known thermomechanical fatigue data for Mo we have applied the Transient Photothermal Deflection (TPD) technique to develop a model f the N-on-i damage ofMo mirrors to predict their multipulse lifetimes. In laser-damage experiments to verify the model mechanically polished Mo mirrors were irradiated with 10 ns Nd:YAG laser pulses at 1064 nm at a 10 Hz rep rate. In the TPD experiments the approximately 600 jtm diameter Nd:YAG laser spot was probed off axis by a smaller HeNe laser beam whose deflection was detected by a fast bicell photodetector and amplifier. Digitized photodetector waveforms indicated that the surface angular deflection could be converted into surfae disp1zement. In addition thermal modelling of the vertical heat distribution enabled the peak surface-deflection signal to be converted into peak surfwe temperawre. The thermomechanical model was verified by both the experimental and model results. Conventional mechanical fatigue data for Mo were used to derive a predictive equation for the laser-accumulation lifetime of Mo mirrors. Experiments were performed with one to 1O'' pulses per site yielding laser-damage thresholds and accumulation curves. The accumulation behavior predicted from measurennts of mechanical fatigue was in excellent agreement with the measured behavior. It is possible that data on high-cycle ( mechanical fatigue can be used to predict the performance of optical surfaces at equally large values of N.

  6. Experiences of patients with abnormal extubation of PICC tubes: a qualitative study

    PubMed Central

    Gao, Wei; Luan, Xiao-Rong; Sun, Yuan-Yuan; Zhang, Ming; Li, Kan; Li, Qiu-Huan; Zhang, Hong; Liu, De-Shan

    2015-01-01

    Objective: To explore the experiences of patients with abnormal extubation of PICC tubes. Methods: Using phenomenological research methods, 15 cases of patients with abnormal extubation of PICC tubes were enrolled in semi-structured interviews. Data were analyzed by Nancy’s phenomenological procedure. Results: After abnormal extubation, patients exhibited conflicting complicated mood which combined negative experience and positive experience. Negative experience was mainly for complaint, helpless, worry and fear. Positive experience was mainly for relief and peace of mind. Conclusions: Patients with abnormal extubation often possessed negative experience. So nursing staff should be suggested to communicate with patients before extubation in order to reduce the dispute between nurses and patients. At the same time, we should summarize and analyze the reasons and factors for abnormal extubation, and take targeted intervention measures in clinical to ensure the safety and effectiveness of PICC extubation. PMID:26770567

  7. TNF Receptor 1/2 Predict Heart Failure Risk in Type 2 Diabetes Mellitus Patients.

    PubMed

    Ping, Zhang; Aiqun, Ma; Jiwu, Li; Liang, Shao

    2017-04-06

    Inflammation plays an important role in heart failure and diabetes mellitus. Traditional serum markers have limited predictive value in heart failure and diabetes. TNFR1 and TNFR2 (TNFR1/2) have been proven to be strongly associated with heart failure and diabetes complications. This study aimed to assess the association of sTNFR1 and sTNFR2 levels and incidental HF risk in diabetes patients.We detected the mRNA, protein, and serum expression of TNFR1/2, their downstream signaling pathway protein NF-kB, and JNK expression and some traditional serum inflammatory markers in a heart failure group without diabetes mellitus or abnormal glucose tolerance (n = 84), a diabetes mellitus group without heart failure (n = 86), and a heart failure with diabetes mellitus group (n = 86).TNFR1/2 were significantly higher in patients with heart failure and diabetes mellitus based on mRNA expression to protein expression and serum expression. However, there were no differences in mRNA, protein, and serum levels of TNFR1/2 between the HF group and DM group. Furthermore, there were no differences between the groups in some traditional serum inflammatory markers.This study demonstrated higher expressions of TNFR, NF-kB, and JNK in patients with heart failure and diabetes mellitus. Compared with traditional serum markers, TNFR1 and TNFR2 are associated with heart failure risk in type 2 diabetes mellitus patients.

  8. Validation of the Denver Emergency Department Trauma Organ Failure Score to Predict Post-Injury Multiple Organ Failure.

    PubMed

    Vogel, Jody A; Newgard, Craig D; Holmes, James F; Diercks, Deborah B; Arens, Ann M; Boatright, Dowin H; Bueso, Antonio; Gaona, Samuel D; Gee, Kaitlin Z; Nelson, Anna; Voros, Jeremy J; Moore, Ernest E; Colwell, Christopher B; Haukoos, Jason S

    2016-01-01

    Early recognition of trauma patients at risk for multiple organ failure (MOF) is important to reduce the morbidity and mortality associated with MOF. The objective of the study was to externally validate the Denver Emergency Department (ED) Trauma Organ Failure (TOF) Score, a 6-item instrument that includes age, intubation, hematocrit, systolic blood pressure, blood urea nitrogen, and white blood cell count, which was designed to predict the development of MOF within 7 days of hospitalization. We performed a prospective multicenter study of adult trauma patients between November, 2011 and March, 2013. The primary outcome was development of MOF within 7 days of hospitalization, assessed using the Sequential Organ Failure Assessment Score. Hierarchical logistic regression analysis was performed to determine associations between the Denver ED TOF Score and MOF. Discrimination was assessed and quantified using a receiver operating characteristics (ROC) curve. The predictive accuracy of the Denver ED TOF score was compared with attending emergency physician estimation of the likelihood of MOF. We included 2,072 patients with a median age of 46 years (interquartile range [IQR] 30 to 61 years); 68% were male. The median Injury Severity Score was 9 (IQR 5 to 17), and 88% of patients had blunt mechanism injury. Among participants, 1,024 patients (49%) were admitted to the ICU, and 77 (4%) died. Multiple organ failure occurred in 120 (6%; 95% CI 5% to 7%) patients and of these, 37 (31%; 95% CI 23% to 40%) died. The area under the ROC curve for the Denver ED TOF Score prediction of MOF was 0.89 (95% CI 0.86 to 0.91) and for physician estimation of the likelihood of MOF was 0.78 (95% CI 0.73 to 0.83). The Denver ED TOF Score predicts development of MOF within 7 days of hospitalization. Its predictive accuracy outperformed attending emergency physician estimation of the risk of MOF. Copyright © 2016 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Can success and failure be predicted for baccalaureate graduates on the computerized NCLEX-RN?

    PubMed

    Seldomridge, Lisa A; Dibartolo, Mary C

    2004-01-01

    The current shortage of nurses and declining national pass rate on the National Council Licensure Examination for Registered Nurses (NCLEX-RN) has heightened educators' interest in identifying students at risk for failure. A retrospective descriptive study was conducted at a rural, public baccalaureate nursing program to determine variables that best predict NCLEX-RN success and failure. Data collected from 1998 through 2002 (N = 186) included entry as native or transfer student, preadmission grade point average (GPA), GPA after completing one semester of nursing courses, cumulative GPA at graduation, grades earned in prerequisite and core nursing courses, test averages in beginning and advanced medical/surgical nursing courses, and performance on the National League for Nursing Comprehensive Achievement Test for Baccalaureate Students (NLNCATBS). Logistic regression analysis revealed that a combination of test average in advanced medical/surgical nursing and percentile score on the NLNCATBS predicted 94.7 percent of NCLEX-RN passes and 33.3 percent of failures. The combination of NLNCATBS score and pathophysiology grade predicted 93.3 percent of NCLEX-RN passes and 50 percent of failures. Although success could be accurately predicted across all models, predicting failure was far more difficult.

  10. A new method for failure prediction of SR-200 beryllium sheet structures

    NASA Technical Reports Server (NTRS)

    Papados, P. P.; Roschke, P. N.

    1994-01-01

    Contemporary applications of failure criteria frequently incorporate two-dimensional or simplified three-dimensional methodologies for prediction of stresses. Motivation behind the development of a new multi-dimensional failure criterion is due mainly to the lack of a sufficiently accurate mathematical tool that accounts for the behavior of brittle material with anisotropic properties. Such a criterion should be able to provide a reliable maximum load estimate so that design of the structure is not penalized in terms of excessive weight requirements. The failure criterion developed is represented by a fracture surface in a six-dimensional stress space. The criterion is applied for failure prediction of SR-200 beryllium sheet structures, a non-homogeneous orthotropic material used widely in space applications. Two experiments are used to verify the criterion.

  11. Predicting the Failure Behavior of Textile Composite Laminates by Using a Multi-Scale Correlating Approach

    NASA Astrophysics Data System (ADS)

    Deng, Yan; Chen, Xiuhua; Wang, Hai

    2015-12-01

    This paper investigates the elastic and failure behavior of textile composite laminates by using an analytical multi-scale correlating approach. The analyses are performed under the four scale levels, i.e. the laminate scale, representative unit cell (RUC) scale, tow architecture scale and fiber/matrix scale levels. The correlation between different scales is derived based on the continuum mechanics and homogenization method from which the stress and strain fields in multiple scales can be obtained concurrently. Effective modulus and ultimate failure strengths of different textile composite (plain weave, twill weave and satin weave) laminates are predicted solely from the corresponding constituent properties, braid geometrical parameters and lay-up. The damage and failure mechanisms at the constituent level are also determined by the micromechanical failure criteria. All the predicted results compare favorably with available experimental data. Parametric studies are also performed to examine the effect of various mechanical and geometrical parameters on the resulting mechanical properties.

  12. Failure to predict difficult tracheal intubation for emergency caesarean section.

    PubMed

    Basaranoglu, Gokcen; Columb, Malachy; Lyons, Gordon

    2010-11-01

    Difficult tracheal intubation following induction of general anaesthesia for caesarean section is a cause of morbidity and mortality. Our aim was to evaluate five bedside predictors that might identify women with potential intubation difficulty immediately prior to emergency caesarean section. Women requiring emergency caesarean section with general anaesthesia and tracheal intubation who had been assessed by the same experienced anaesthesiologist preoperatively were included in this study. Mallampati score, sternomental distance, thyromental distance, interincisor gap and atlantooccipital extension were all measured. The same anaesthesiologist performed laryngoscopy and graded the laryngeal view according to Cormack and Lehane. Exact logistic regression was used to identify significant independent predictors for difficult intubation (Cormack and Lehane grades ≥ 3) with two-sided P value less than 0.05 considered as significant. In 3 years, 239 women were recruited. Cormack and Lehane grades of 2 or less (easy) were found in 225 and grade of at least 3 (difficult) in 14 women. Patients' characteristics (age, height, weight, BMI or weight gain) were not significantly associated with difficulty of intubation. The incidence of difficult intubation was 1/17 women [95% confidence interval (CI) from 1/31 to 1/10]. A positive result from any of the five predictors combined had a sensitivity of 0.21 (95%CI 0.05-0.51), a specificity of 0.92 (95%CI 0.88-0.96), a positive predictive value of 0.15 (95%CI 0.032-0.38) and a negative predictive value of 0.95 (95%CI 0.91-0.97) for a Cormack and Lehane grade of at least 3 at laryngoscopy. Airway assessment using these tests cannot be relied upon to predict a difficult intubation at emergency caesarean section as the low sensitivity means that 79% (95%CI 49-95) of difficult intubations will be missed.

  13. Probability of failure prediction for step-stress fatigue under sine or random stress

    NASA Technical Reports Server (NTRS)

    Lambert, R. G.

    1979-01-01

    A previously proposed cumulative fatigue damage law is extended to predict the probability of failure or fatigue life for structural materials with S-N fatigue curves represented as a scatterband of failure points. The proposed law applies to structures subjected to sinusoidal or random stresses and includes the effect of initial crack (i.e., flaw) sizes. The corrected cycle ratio damage function is shown to have physical significance.

  14. Probability of failure prediction for step-stress fatigue under sine or random stress

    NASA Technical Reports Server (NTRS)

    Lambert, R. G.

    1979-01-01

    A previously proposed cumulative fatigue damage law is extended to predict the probability of failure or fatigue life for structural materials with S-N fatigue curves represented as a scatterband of failure points. The proposed law applies to structures subjected to sinusoidal or random stresses and includes the effect of initial crack (i.e., flaw) sizes. The corrected cycle ratio damage function is shown to have physical significance.

  15. The unrecognised difficult extubation: a call for vigilance.

    PubMed

    Antoine, J; Hussain, Z; El-Sayed, I; Apfel, C C

    2010-09-01

    Tracheal extubation remains a critical and often overlooked period of difficult airway management. A 66-year-old man, scheduled for C5-C7 anterior fusion, with an easy view of the vocal cords, presented with a sublaryngeal obstruction that required a reduced tracheal tube size. Despite correct tube placement, intra-operative ventilation remained difficult. At the end of surgery a pulsatile tracheal compression was fibreopticially observed above the carina. After discussion with the attending otolaryngologist, neuromuscular blockade was antagonised and the patient was able to maintain normal minute volumes while spontaneously ventilating. With the otolaryngologist present, and with the patient conscious, the trachea was successfully extubated over an airway exchange catheter. A subsequent CT scan revealed an impingement of the trachea by the innominate artery and a mildly ectatic ascending and descending aorta that, in conjunction with tracheomalacia and neuromuscular blockade, could explain the observed signs and symptoms.

  16. Methodology to predict the number of forced outages due to creep failure

    SciTech Connect

    Palermo, J.V. Jr.

    1996-12-31

    All alloy metals at a temperature above 950 degrees Fahrenheit experience creep damage. Creep failures in boiler tubes usually begin after 25 to 40 years of operation. Since creep damage is irreversible, the only remedy is to replace the tube sections. By predicting the number of failures per year, the utility can make the best economic decision concerning tube replacement. This paper describes a methodology to calculate the number of forced outages per yea due to creep failures. This methodology is particularly useful to utilities that have boilers that have at least 25 years of operation.

  17. Cough augmentation techniques for extubation or weaning critically ill patients from mechanical ventilation.

    PubMed

    Rose, Louise; Adhikari, Neill Kj; Leasa, David; Fergusson, Dean A; McKim, Douglas

    2017-01-11

    There are various reasons why weaning and extubation failure occur, but ineffective cough and secretion retention can play a significant role. Cough augmentation techniques, such as lung volume recruitment or manually- and mechanically-assisted cough, are used to prevent and manage respiratory complications associated with chronic conditions, particularly neuromuscular disease, and may improve short- and long-term outcomes for people with acute respiratory failure. However, the role of cough augmentation to facilitate extubation and prevent post-extubation respiratory failure is unclear. Our primary objective was to determine extubation success using cough augmentation techniques compared to no cough augmentation for critically-ill adults and children with acute respiratory failure admitted to a high-intensity care setting capable of managing mechanically-ventilated people (such as an intensive care unit, specialized weaning centre, respiratory intermediate care unit, or high-dependency unit).Secondary objectives were to determine the effect of cough augmentation techniques on reintubation, weaning success, mechanical ventilation and weaning duration, length of stay (high-intensity care setting and hospital), pneumonia, tracheostomy placement and tracheostomy decannulation, and mortality (high-intensity care setting, hospital, and after hospital discharge). We evaluated harms associated with use of cough augmentation techniques when applied via an artificial airway (or non-invasive mask once extubated/decannulated), including haemodynamic compromise, arrhythmias, pneumothorax, haemoptysis, and mucus plugging requiring airway change and the type of person (such as those with neuromuscular disorders or weakness and spinal cord injury) for whom these techniques may be efficacious. We searched the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 4, 2016), MEDLINE (OvidSP) (1946 to April 2016), Embase (OvidSP) (1980 to April 2016), CINAHL (EBSCOhost) (1982

  18. Endothelial Cell Density to Predict Endothelial Graft Failure After Penetrating Keratoplasty

    PubMed Central

    Lass, Jonathan H.; Sugar, Alan; Benetz, Beth Ann; Beck, Roy W.; Dontchev, Mariya; Gal, Robin L.; Kollman, Craig; Gross, Robert; Heck, Ellen; Holland, Edward J.; Mannis, Mark J.; Raber, Irving; Stark, Walter; Stulting, R. Doyle

    2010-01-01

    Objective To determine whether preoperative and/or postoperative central endothelial cell density (ECD) and its rate of decline postoperatively are predictive of graft failure caused by endothelial decompensation following penetrating keratoplasty to treat a moderate-risk condition, principally, Fuchs dystrophy or pseudophakic corneal edema. Methods In a subset of Cornea Donor Study participants, a central reading center determined preoperative and postoperative ECD from available specular images for 17 grafts that failed because of endothelial decompensation and 483 grafts that did not fail. Results Preoperative ECD was not predictive of graft failure caused by endothelial decompensation (P = .91). However, the 6-month ECD was predictive of subsequent failure (P < .001). Among those that had not failed within the first 6 months, the 5-year cumulative incidence (±95% confidence interval) of failure was 13% (±12%) for the 33 participants with a 6-month ECD of less than 1700 cells/mm2 vs 2%(±3%) for the 137 participants with a 6-monthECDof 2500 cells/mm2 or higher. After 5 years’ follow-up, 40 of 277 participants (14%) with a clear graft had an ECD below 500 cells/mm2. Conclusions Preoperative ECD is unrelated to graft failure from endothelial decompensation, whereas there is a strong correlation of ECD at 6 months with graft failure from endothelial decompensation. A graft can remain clear after 5 years even when the ECD is below 500 cells/mm2. PMID:20065219

  19. Heart Failure: Diagnosis, Severity Estimation and Prediction of Adverse Events Through Machine Learning Techniques.

    PubMed

    Tripoliti, Evanthia E; Papadopoulos, Theofilos G; Karanasiou, Georgia S; Naka, Katerina K; Fotiadis, Dimitrios I

    2017-01-01

    Heart failure is a serious condition with high prevalence (about 2% in the adult population in developed countries, and more than 8% in patients older than 75 years). About 3-5% of hospital admissions are linked with heart failure incidents. Heart failure is the first cause of admission by healthcare professionals in their clinical practice. The costs are very high, reaching up to 2% of the total health costs in the developed countries. Building an effective disease management strategy requires analysis of large amount of data, early detection of the disease, assessment of the severity and early prediction of adverse events. This will inhibit the progression of the disease, will improve the quality of life of the patients and will reduce the associated medical costs. Toward this direction machine learning techniques have been employed. The aim of this paper is to present the state-of-the-art of the machine learning methodologies applied for the assessment of heart failure. More specifically, models predicting the presence, estimating the subtype, assessing the severity of heart failure and predicting the presence of adverse events, such as destabilizations, re-hospitalizations, and mortality are presented. According to the authors' knowledge, it is the first time that such a comprehensive review, focusing on all aspects of the management of heart failure, is presented.

  20. Endothelial cell density to predict endothelial graft failure after penetrating keratoplasty.

    PubMed

    Lass, Jonathan H; Sugar, Alan; Benetz, Beth Ann; Beck, Roy W; Dontchev, Mariya; Gal, Robin L; Kollman, Craig; Gross, Robert; Heck, Ellen; Holland, Edward J; Mannis, Mark J; Raber, Irving; Stark, Walter; Stulting, R Doyle

    2010-01-01

    To determine whether preoperative and/or postoperative central endothelial cell density (ECD) and its rate of decline postoperatively are predictive of graft failure caused by endothelial decompensation following penetrating keratoplasty to treat a moderate-risk condition, principally, Fuchs dystrophy or pseudophakic corneal edema. In a subset of Cornea Donor Study participants, a central reading center determined preoperative and postoperative ECD from available specular images for 17 grafts that failed because of endothelial decompensation and 483 grafts that did not fail. Preoperative ECD was not predictive of graft failure caused by endothelial decompensation (P = .91). However, the 6-month ECD was predictive of subsequent failure (P < .001). Among those that had not failed within the first 6 months, the 5-year cumulative incidence (+/-95% confidence interval) of failure was 13% (+/-12%) for the 33 participants with a 6-month ECD of less than 1700 cells/mm(2) vs 2% (+/-3%) for the 137 participants with a 6-month ECD of 2500 cells/mm(2) or higher. After 5 years' follow-up, 40 of 277 participants (14%) with a clear graft had an ECD below 500 cells/mm(2). Preoperative ECD is unrelated to graft failure from endothelial decompensation, whereas there is a strong correlation of ECD at 6 months with graft failure from endothelial decompensation. A graft can remain clear after 5 years even when the ECD is below 500 cells/mm(2).

  1. An investigation of gear mesh failure prediction techniques. M.S. Thesis - Cleveland State Univ.

    NASA Technical Reports Server (NTRS)

    Zakrajsek, James J.

    1989-01-01

    A study was performed in which several gear failure prediction methods were investigated and applied to experimental data from a gear fatigue test apparatus. The primary objective was to provide a baseline understanding of the prediction methods and to evaluate their diagnostic capabilities. The methods investigated use the signal average in both the time and frequency domain to detect gear failure. Data from eleven gear fatigue tests were recorded at periodic time intervals as the gears were run from initiation to failure. Four major failure modes, consisting of heavy wear, tooth breakage, single pits, and distributed pitting were observed among the failed gears. Results show that the prediction methods were able to detect only those gear failures which involved heavy wear or distributed pitting. None of the methods could predict fatigue cracks, which resulted in tooth breakage, or single pits. It is suspected that the fatigue cracks were not detected because of limitations in data acquisition rather than in methodology. Additionally, the frequency response between the gear shaft and the transducer was found to significantly affect the vibration signal. The specific frequencies affected were filtered out of the signal average prior to application of the methods.

  2. Validated model for predicting postoperative respiratory failure: analysis of 1706 abdominal wall reconstructions.

    PubMed

    Fischer, John P; Shang, Eric K; Butler, Charles E; Nelson, Jonas A; Braslow, Benjamin M; Serletti, Joseph M; Kovach, Stephen J

    2013-11-01

    Abdominal wall reconstruction can be associated with significant rates of respiratory events. In this current study, the authors aim to characterize perioperative risk factors associated with postoperative respiratory failure and derive a model with which to predict postoperative respiratory failure. The authors reviewed the 2005 to 2010 American College of Surgeons National Surgical Quality Improvement Program databases, identifying encounters for Current Procedural Terminology codes for both hernia repair (49560, 49561, 49565, 49566, and 49568) and component separation (15734). A predictive model of postoperative respiratory failure was developed using logistic regression analyses and validated using a bootstrap technique. Of 1706 patients undergoing complex abdominal reconstructions in the study period, 102 (6.0 percent) experienced postoperative respiratory failure. Patients experiencing postoperative respiratory failure had longer admissions (21.0±18.5 versus 5.9±5.5 days, p<0.001) and a higher mortality rate (14.7 percent versus 0.1 percent, p<0.001). Multivariate logistic regression revealed eight variables significantly associated with postoperative respiratory failure. A history of chronic obstructive pulmonary disease (p<0.001), dyspnea at rest (p=0.032), dependent functional status (p=0.032), malnutrition (p<0.001), recurrent incarcerated hernia (p=0.006), concurrent intraabdominal procedure (p=0.041), American Society of Anesthesiologists score greater than 3 (p<0.001), and prolonged operative time (p<0.001) were independently associated with higher rates of postoperative respiratory failure. The multivariate model was internally validated using a bootstrap technique and had good discrimination (c statistic=0.78). A validated predictive model and clinical risk-assessment tool of postoperative respiratory failure following abdominal wall reconstruction is presented. Respiratory complications were associated with significantly longer hospital stays and

  3. Feasibility of using adaptive logic networks to predict compressor unit failure

    SciTech Connect

    Armstrong, W.W.; Chungying Chu; Thomas, M.M.

    1995-12-31

    In this feasibility study, an adaptive logic network (ALN) was trained to predict failures of turbine-driven compressor units using a large database of measurements. No expert knowledge about compressor systems was involved. The predictions used only the statistical properties of the measurements and the indications of failure types. A fuzzy set was used to model measurements typical of normal operation. It was constrained by a requirement imposed during ALN training, that it should have a shape similar to a Gaussian density, more precisely, that its logarithm should be convex-up. Initial results obtained using this approach to knowledge discovery in the database were encouraging.

  4. Breathing measurement reduces false-negative classification of tachypneic preextubation trial failures.

    PubMed

    DeHaven, C B; Kirton, O C; Morgan, J P; Hart, A M; Shatz, D V; Civetta, J M

    1996-06-01

    breathing, as the increased respiratory rate usually abated within 18 hrs after extubation. The reliance on a respiratory rate of predictive value of 92%, a negative predictive value of 8%, and an overall accuracy of 77%. The average duration of mechanical ventilation during the study period decreased by 2 days, from 8.6 to 6.3 days (p=.03). Tachypnea as a marker of respiratory distress is sensitive, but is not sufficiently specific to be used as a criterion in preextubation trials. Reliance on tachypnea as a preextubation trial failure criterion is likely to prolong intubation and ventilatory support for a large number of patients. Patient risks, determined by the extubation failures and reintubation rate, are the same.

  5. Prediction of Ductile Failure in the Stretch-Forming of AA2024 Sheets

    SciTech Connect

    Vallellano, C.; Guzman, C.; Garcia-Lomas, F. J.

    2007-05-17

    A number of ductile failure criteria are nowadays being used to predict the formability of aluminium alloy sheets. Generally speaking, integral criteria (e.g. those proposed by Cockcroft and Latham, Brozzo et al., Oyane et al Chaouadi et al., etc.) have been probed to work well when the principal strains are of opposite sign, i.e. in the left side of the Forming Limit Diagram (FLD). However, when tensile biaxial strains are present, as occurs in stretch-forming practice, their predictions are usually very poor and even non-conservatives. As an alternative, local criteria, such as the classical Tresca's and Bressan and Williams' criteria, have demonstrated a good capability to predict the failure in some automotive aluminum alloys under stretching. The present work analyses experimentally and numerically the failure in AA2024-T3 sheets subjected to biaxial stretching. A series of out-of-plane stretching tests have been simulated using ABAQUS. The experimental and the numerical FLD for different failure criteria are compared. The influence on the failure of the hydrostatic pressure and the normal stress to the fracture plane is also discussed.

  6. Factors predicting survival for HIV-infected patients with respiratory failure.

    PubMed

    van Leeuwen, H J; Boereboom, F T; Pols, M A; Hoepelman, A I; Savelkoul, J T

    2000-09-01

    Despite improved treatment modalities, the mortality of HIV infected patients admitted to the intensive care unit with respiratory failure remains high. To help ICU physicians in advising HIV infected patients whether to undergo mechanical ventilation, we retrospectively investigated prognostic factors predicting hospital outcome for HIV-infected patients, admitted to a medical intensive care unit with respiratory failure before the era of highly-active anti-retroviral therapy. A retrospective chart review was carried out of all HIV-infected patients with respiratory failure admitted to the medical ICU of a Dutch University Hospital between 1991 and 1997. In the six year period, 29 HIV-infected patients were admitted to the ICU for respiratory failure. Mechanical ventilation, CD4 cell count, APACHE II score, APACHE III score, ARDS and length of ICU stay all differed significantly between survivors and non-survivors. However, a multivariate analysis only showed the need for mechanical ventilation as an independent risk factor for mortality. The only combination of factors able to accurately predict mortality for the individual patient was the development of ARDS and the requirement of mechanical ventilation. The combination of mechanical ventilation and ARDS accurately predicts hospital outcome in HIV-infected patients presenting with respiratory failure before the HAART era.

  7. Predicting age of ovarian failure after radiation to a field that includes the ovaries

    SciTech Connect

    Wallace, W. Hamish B. . E-mail: Hamish.Wallace@ed.ac.uk; Thomson, Angela B.; Saran, Frank; Kelsey, Tom W.

    2005-07-01

    Purpose: To predict the age at which ovarian failure is likely to develop after radiation to a field that includes the ovary in women treated for cancer. Methods and Materials: Modern computed tomography radiotherapy planning allows determination of the effective dose of radiation received by the ovaries. Together with our recent assessment of the radiosensitivity of the human oocyte, the effective surviving fraction of primordial oocytes can be determined and the age of ovarian failure, with 95% confidence limits, predicted for any given dose of radiotherapy. Results: The effective sterilizing dose (ESD: dose of fractionated radiotherapy [Gy] at which premature ovarian failure occurs immediately after treatment in 97.5% of patients) decreases with increasing age at treatment. ESD at birth is 20.3 Gy; at 10 years 18.4 Gy, at 20 years 16.5 Gy, and at 30 years 14.3 Gy. We have calculated 95% confidence limits for age at premature ovarian failure for estimated radiation doses to the ovary from 1 Gy to the ESD from birth to 50 years. Conclusions: We report the first model to reliably predict the age of ovarian failure after treatment with a known dose of radiotherapy. Clinical application of this model will enable physicians to counsel women on their reproductive potential following successful treatment.

  8. Multiple immune deviations predictive for IVF failure as possible markers for IVIG therapy.

    PubMed

    Chernyshov, Viktor P; Dons'koi, Boris V; Sudoma, Iryna O; Goncharova, Yana O

    2016-08-01

    Recently we have shown that immune deviations (ID) may predict IVF failure. Benefit from IVIG therapy was observed in 115 women with repeated IVF failure according to proposed multiple ID that appeared unfavorable for implantation and live birth. Group of 123 women with repeated IVF failure without IVIG therapy was compared with former group. Immune phenotype and NK activity of peripheral blood lymphocytes were studied by flow cytometry. Potentially predictive for IVF failure ID included elevated expression of CD56, CD158a in T lymphocytes, decreased levels of CD4T lymphocytes, up-regulated expression of HLA DR in CD8+ T cells and NK cells, elevated number of NK cells and increased NK cytotoxicity, increased or decreased expression of CD158a and CD8 in NK cells. Three or more ID may predict implantation failure to a greater degree than one or two ID. In women receiving IVIG in subgroups with 0-1 and 2 ID, there was no increase in implantation rate (IR) and live birth rate (LBR) after IVIG in comparison with patients with the same number of ID but without IVIG correction. After IVIG therapy decreased IR and LBR were restored in women with three or more immune deviations. Multiple immune deviations indicate IVF patients who may benefit from IVIG therapy. IVIG seems to convert "unfavorable" immune phenotype to "favorable" one.

  9. Health Literacy Predicts Morbidity and Mortality in Rural Patients With Heart Failure.

    PubMed

    Moser, Debra K; Robinson, Susan; Biddle, Martha J; Pelter, Michele M; Nesbitt, Thomas S; Southard, Jeffery; Cooper, Lawton; Dracup, Kathleen

    2015-08-01

    Patients hospitalized with heart failure are often readmitted. Health literacy may play a substantial role in the high rate of readmissions. The purpose of this study was to examine the association of health literacy with the composite end point of heart failure readmission rates and all-cause mortality in patients with heart failure living in rural areas. Rural adults (n = 575), hospitalized for heart failure within the past 6 months, completed the Short Test of Functional Health Literacy in Adults (STOFHLA) to measure health literacy and were followed for ≥2 years. The percentage of patients with the end point of heart failure readmission or all-cause death was different (P = .001) among the 3 STOFHLA score levels. Unadjusted analysis revealed that patients with inadequate and marginal health literacy were 1.94 (95% confidence interval [CI] 1.43-2.63; P < .001) times, and 1.91 (95% CI 1.36-2.67; P < .001) times, respectively, more likely to experience the outcome. After adjustment for covariates, health literacy remained a predictor of outcomes. Of the other covariates, worse functional class, higher comorbidity burden, and higher depression score predicted worse outcomes. Inadequate or marginal health literacy is a risk factor for heart failure rehospitalization or all-cause mortality among rural patients with heart failure. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Time-dependent Predictive Values of Prognostic Biomarkers with Failure Time Outcome.

    PubMed

    Zheng, Yingye; Cai, Tianxi; Pepe, Margaret S; Levy, Wayne C

    2008-01-01

    In a prospective cohort study, information on clinical parameters, tests and molecular markers is often collected. Such information is useful to predict patient prognosis and to select patients for targeted therapy. We propose a new graphical approach, the positive predictive value (PPV) curve, to quantify the predictive accuracy of prognostic markers measured on a continuous scale with censored failure time outcome. The proposed method highlights the need to consider both predictive values and the marker distribution in the population when evaluating a marker, and it provides a common scale for comparing different markers. We consider both semiparametric and nonparametric based estimating procedures. In addition, we provide asymptotic distribution theory and resampling based procedures for making statistical inference. We illustrate our approach with numerical studies and datasets from the Seattle Heart Failure Study.

  11. Predicting Outcomes of Hospitalization for Heart Failure Using Logistic Regression and Knowledge Discovery Methods

    PubMed Central

    Phillips, Kirk T.; Street, W. Nick

    2005-01-01

    The purpose of this study is to determine the best prediction of heart failure outcomes, resulting from two methods -- standard epidemiologic analysis with logistic regression and knowledge discovery with supervised learning/data mining. Heart failure was chosen for this study as it exhibits higher prevalence and cost of treatment than most other hospitalized diseases. The prevalence of heart failure has exceeded 4 million cases in the U.S.. Findings of this study should be useful for the design of quality improvement initiatives, as particular aspects of patient comorbidity and treatment are found to be associated with mortality. This is also a proof of concept study, considering the feasibility of emerging health informatics methods of data mining in conjunction with or in lieu of traditional logistic regression methods of prediction. Findings may also support the design of decision support systems and quality improvement programming for other diseases. PMID:16779367

  12. Prediction of Composite Pressure Vessel Failure Location using Fiber Bragg Grating Sensors

    NASA Technical Reports Server (NTRS)

    Kreger, Steven T.; Taylor, F. Tad; Ortyl, Nicholas E.; Grant, Joseph

    2006-01-01

    Ten composite pressure vessels were instrumented with fiber Bragg grating sensors in order to assess the strain levels of the vessel under various loading conditions. This paper and presentation will discuss the testing methodology, the test results, compare the testing results to the analytical model, and present a possible methodology for predicting the failure location and strain level of composite pressure vessels.

  13. Prediction of Brittle Failure for TBM Tunnels in Anisotropic Rock: A Case Study from Northern Norway

    NASA Astrophysics Data System (ADS)

    Dammyr, Øyvind

    2016-06-01

    Prediction of spalling and rock burst is especially important for hard rock TBM tunneling, because failure can have larger impact than in a drill and blast tunnel and ultimately threaten excavation feasibility. The majority of research on brittle failure has focused on rock types with isotropic behavior. This paper gives a review of existing theory and its application before a 3.5-m-diameter TBM tunnel in foliated granitic gneiss is used as a case to study brittle failure characteristics of anisotropic rock. Important aspects that should be considered in order to predict brittle failure in anisotropic rock are highlighted. Foliation is responsible for considerable strength anisotropy and is believed to influence the preferred side of v-shaped notch development in the investigated tunnel. Prediction methods such as the semi- empirical criterion, the Hoek- Brown brittle parameters, and the non-linear damage initiation and spalling limit method give reliable results; but only as long as the angle between compression axis and foliation in uniaxial compressive tests is relevant, dependent on the relation between tunnel trend/plunge, strike/dip of foliation, and tunnel boundary stresses. It is further demonstrated that local in situ stress variations, for example, due to the presence of discontinuities, can have profound impact on failure predictions. Other carefully documented case studies into the brittle failure nature of rock, in particular anisotropic rock, are encouraged in order to expand the existing and relatively small database. This will be valuable for future TBM planning and construction stages in highly stressed brittle anisotropic rock.

  14. A model for predicting embankment slope failures in clay-rich soils; A Louisiana example

    NASA Astrophysics Data System (ADS)

    Burns, S. F.

    2015-12-01

    A model for predicting embankment slope failures in clay-rich soils; A Louisiana example It is well known that smectite-rich soils significantly reduce the stability of slopes. The question is how much smectite in the soil causes slope failures. A study of over 100 sites in north and south Louisiana, USA, compared slopes that failed during a major El Nino winter (heavy rainfall) in 1982-1983 to similar slopes that did not fail. Soils in the slopes were tested for per cent clay, liquid limits, plasticity indices and semi-quantitative clay mineralogy. Slopes with the High Risk for failure (85-90% chance of failure in 8-15 years after construction) contained soils with a liquid limit > 54%, a plasticity index over 29%, and clay contents > 47%. Slopes with an Intermediate Risk (55-50% chance of failure in 8-15 years) contained soils with a liquid limit between 36-54%, plasticity index between 16-19%, and clay content between 32-47%. Slopes with a Low Risk chance of failure (< 5% chance of failure in 8-15 years after construction) contained soils with a liquid limit < 36%, a plasticity index < 16%, and a clay content < 32%. These data show that if one is constructing embankments and one wants to prevent slope failure of the 3:1 slopes, check the above soil characteristics before construction. If the soils fall into the Low Risk classification, construct the embankment normally. If the soils fall into the High Risk classification, one will need to use lime stabilization or heat treatments to prevent failures. Soils in the Intermediate Risk class will have to be evaluated on a case by case basis.

  15. Noninvasive Failure Load Prediction of Vertebrae with Simulated Lytic Defects and Biomaterial Augmentation.

    PubMed

    Giambini, Hugo; Fang, Zhong; Zeng, Heng; Camp, Jon J; Yaszemski, Michael J; Lu, Lichun

    2016-08-01

    The spine is the most common site for secondary bone metastases, and clinical management for fractures is based on size and geometry of the defect. About 75% of the bone needs to be damaged before lesions are detectable, so clinical tools should measure changes in both geometry and material properties. We have developed an automated, user-friendly, Spine Cancer Assessment (SCA) image-based analysis method that builds on a platform designed for clinical practice providing failure characteristics of vertebrae. The objectives of this study were to (1) validate SCA predictions with experimental failure load outcomes; (2) evaluate the planning capabilities for prophylactic vertebroplasty procedures; and (3) investigate the effect of computed tomography (CT) protocols on predicted failure loads. Twenty-one vertebrae were randomly divided into two groups: (1) simulated defect without treatment (negative control) [n = 9] and (2) with treatment [n = 12]. Defects were created and a polymeric biomaterial was injected into the vertebrae in the treated-defect group. Spines were scanned, reconstructed with two algorithms, and analyzed for fracture loads. To virtually plan for prophylactic intervention, vertebrae with empty lesions were simulated to be augmented with either poly(methyl methacrylate) (PMMA) or a novel bone replacement copolymer, poly(propylene fumarate-co-caprolactone) [P(PF-co-CL)]. Axial rigidities were calculated from the CT images. Failure loads, determined from the cross section with the lowest axial rigidity, were compared with experimental values. Predicted loads correlated well with experimental outcomes (R(2) = 0.73, p < 0.0001). Predictions from negative control specimens highly correlated with measured values (R(2) = 0.90, p < 0.0001). Although a similar correlation was obtained using both algorithms, the smooth reconstruction (B30) tended to underestimate predicted failure loads by ∼50% compared with the ∼10% underestimate

  16. The effect of extraction angle on endotracheal tube extubation force: Simulation and randomized clinical trial.

    PubMed

    Mihara, Ryosuke; Komasawa, Nobuyasu; Matsunami, Sayuri; Minami, Toshiaki

    2015-10-01

    To evaluate the extraction force generated at different extubation angles using a manikin simulation and a randomized clinical trial. Simulations were performed on a manikin to assess the force generated at extubation angles of 0°, 30°, 45°, 60°, 90° and 120° relative to the ground. The trial compared extraction force and changes in vital signs in patients undergoing general anaesthesia with tracheal intubation followed by extubation at 60° or 90°. The simulation study found that the extubation force was significantly lower at 45° and 60° than at all other extraction angles. In the trial, extubation at 60° resulted in significantly lower extraction force and systolic blood pressure elevation (n = 23) than extubation at 90° (n = 23). Findings in a manikin simulation were confirmed by those of a randomized clinical trial, where extubation at 60° required less force than 90°, and was accompanied by less SBP elevation. Extubation at 60° is less invasive than extubation at 90°. © The Author(s) 2015.

  17. A New Method for Extubation: Comparison between Conventional and New Methods

    PubMed Central

    Yousefshahi, Fardin; Barkhordari, Khosro; Movafegh, Ali; Tavakoli, Vida; Paknejad, Omalbanin; Bina, Payvand; Yousefshahi, Hadi; Sheikh Fathollahi, Mahmood

    2012-01-01

    Background: Extubation is associated with the risk of complications such as accumulated secretion above the endotracheal tube cuff, eventual atelectasia following a reduction in pulmonary volumes because of a lack of physiological positive end expiratory pressure, and intra-tracheal suction. In order to reduce these complications, and, based on basic physiological principles, a new practical extubation method is presented in this article. Methods: The study was designed as a six-month prospective cross-sectional clinical trial. Two hundred fifty-seven patients undergoing coronary artery bypass grafting (CABG) were divided into two groups based on their scheduled surgery time. The first group underwent the conventional extubation method, while the other group was extubated according to a new described method. Arterial blood gas (ABG) analysis results before and after extubation were compared between the two groups to find the effect of the extubation method on the ABG parameters and the oxygenation profile. Results: In all time intervals, the partial pressure of oxygen in arterial blood / fraction of inspired oxygen (PaO2/FiO2) ratio in the new method group patients was improved compared to that in the conventional method; some differences, like PaO2/FiO2 four hours after extubation, were statistically significant, however (p value=0.0063). Conclusion: The new extubation method improved some respiratory parameters and thus attenuated oxygenation complications and amplified oxygenation after extubation. PMID:23304181

  18. A New Method for Extubation: Comparison between Conventional and New Methods.

    PubMed

    Yousefshahi, Fardin; Barkhordari, Khosro; Movafegh, Ali; Tavakoli, Vida; Paknejad, Omalbanin; Bina, Payvand; Yousefshahi, Hadi; Sheikh Fathollahi, Mahmood

    2012-08-01

    Extubation is associated with the risk of complications such as accumulated secretion above the endotracheal tube cuff, eventual atelectasia following a reduction in pulmonary volumes because of a lack of physiological positive end expiratory pressure, and intra-tracheal suction. In order to reduce these complications, and, based on basic physiological principles, a new practical extubation method is presented in this article. The study was designed as a six-month prospective cross-sectional clinical trial. Two hundred fifty-seven patients undergoing coronary artery bypass grafting (CABG) were divided into two groups based on their scheduled surgery time. The first group underwent the conventional extubation method, while the other group was extubated according to a new described method. Arterial blood gas (ABG) analysis results before and after extubation were compared between the two groups to find the effect of the extubation method on the ABG parameters and the oxygenation profile. In all time intervals, the partial pressure of oxygen in arterial blood / fraction of inspired oxygen (PaO(2)/FiO(2)) ratio in the new method group patients was improved compared to that in the conventional method; some differences, like PaO(2)/FiO(2) four hours after extubation, were statistically significant, however (p value=0.0063). The new extubation method improved some respiratory parameters and thus attenuated oxygenation complications and amplified oxygenation after extubation.

  19. Identifying the necessary and sufficient number of risk factors for predicting academic failure.

    PubMed

    Lucio, Robert; Hunt, Elizabeth; Bornovalova, Marina

    2012-03-01

    Identifying the point at which individuals become at risk for academic failure (grade point average [GPA] < 2.0) involves an understanding of which and how many factors contribute to poor outcomes. School-related factors appear to be among the many factors that significantly impact academic success or failure. This study focused on 12 school-related factors. Using a thorough 5-step process, we identified which unique risk factors place one at risk for academic failure. Academic engagement, academic expectations, academic self-efficacy, homework completion, school relevance, school safety, teacher relationships (positive relationship), grade retention, school mobility, and school misbehaviors (negative relationship) were uniquely related to GPA even after controlling for all relevant covariates. Next, a receiver operating characteristic curve was used to determine a cutoff point for determining how many risk factors predict academic failure (GPA < 2.0). Results yielded a cutoff point of 2 risk factors for predicting academic failure, which provides a way for early identification of individuals who are at risk. Further implications of these findings are discussed.

  20. Sonographical predictive markers of failure of induction of labour in term pregnancy.

    PubMed

    Brik, Maia; Mateos, Silvia; Fernandez-Buhigas, Irene; Garbayo, Paloma; Costa, Gloria; Santacruz, Belen

    2017-02-01

    Predictive markers of failure of induction of labour in term pregnancy were evaluated. A prospective study including 245 women attending induction of labour was performed. The inclusion criteria were singleton pregnancies, gestational age 37-42 weeks and the main outcomes were failure of induction, induction to delivery interval and mode of delivery. Women with a longer cervical length prior to induction (CLpi) had a higher rate of failure of induction (30.9 ± 6.8 vs. 23.9 ± 9.3, p < .001). BMI was higher and maternal height was lower in the group of caesarean section compared to vaginal delivery (33.1 ± 8 vs. 29.3 ± 4.6, 160 ± 5 vs. 164 ± 5, p < .001, respectively). A shorter CLpi correlated with a shorter induction to delivery interval (R Pearson .237, p < .001). In the regression analysis, for failure of induction the only independent predictor was the CL prior to induction. Therefore, the CLpi is an independent factor for prediction of failure of induction of labour.

  1. Postoperative pulmonary function in coronary artery bypass graft surgery patients undergoing early tracheal extubation: a comparison between short-term mechanical ventilation and early extubation.

    PubMed

    Nicholson, Donna J; Kowalski, Stephen E; Hamilton, G Andrew; Meyers, Michael P; Serrette, Carl; Duke, Peter C

    2002-02-01

    To evaluate the effect of a short period of mechanical ventilation (3 hours) versus immediate extubation (within 1 hour of surgery) on pulmonary function, gas exchange, and pulmonary complications after coronary artery bypass graft (CABG) surgery. Prospective randomized study. University teaching hospital. Thirty-five patients undergoing CABG surgery. Patients were randomized into 2 groups. Patients in group I were extubated as soon as possible after surgery. Patients in group II were ventilated for a minimum of 3 hours after surgery. Patients in both groups were extubated only after achieving predetermined extubation criteria. Patients who did not meet the criteria for extubation within the predetermined set time limit (90 minutes in group I and 6 hours in group II) were withdrawn from the study. Pulmonary function tests (vital capacity, forced expiratory volume in 1 second, total lung capacity, functional residual capacity), arterial blood gases, and chest radiographs were done preoperatively and postoperatively. Pulmonary complications were recorded. Demographic data were similar between groups. The mean time to extubation in group I was 45.7 plus minus 27.6 minutes and in group II was 201.4 plus minus 21 minutes (p < 0.01). Two patients in group I and 1 patient in group II did not meet the extubation criteria within the predetermined set time limit and were excluded from the study. In both groups, there was a significant decline in pulmonary function but no differences between groups at 24 or 72 hours after surgery. There were no differences between groups in blood gases, atelectasis scores, or pulmonary complications. The data suggest that extending mechanical ventilation after CABG surgery does not affect pulmonary function. Provided that routine extubation criteria are met, patients can be safely extubated early (within 1 hour) after major cardiac surgery without concerns of further pulmonary derangement. Copyright 2002, Elsevier Science (USA). All rights

  2. Tumor Necrosis Factor Inhibitor Primary Failure Predicts Decreased Ustekinumab Efficacy in Psoriasis Patients.

    PubMed

    Sorensen, Eric P; Fanucci, Kristina A; Saraiya, Ami; Volf, Eva; Au, Shiu-chung; Argobi, Yahya; Mansfield, Ryan; Gottlieb, Alice B

    2015-08-01

    Additional studies are needed to examine the efficacy of ustekinumab in psoriasis patients who have previously been exposed to tumor necrosis factor inhibitors (TNFi). To examine the predictive effect of TNFi primary failure and the number of TNFi exposures on the efficacy of ustekinumab in psoriasis treatment. This retrospective study examined 44 psoriasis patients treated at the Tufts Medical Center Department of Dermatology between January 2008 and July 2014. Patients were selected if they were treated with ustekinumab and had ≥ 1 previous TNFi exposure. The following subgroups were compared: patients with vs without a previous TNFi primary failure, and patients with one vs multiple previous TNFi exposures. The efficacy measure used was the previously validated Simple Measure for Assessing Psoriasis Activity (S-MAPA), which is calculated by the product of the body surface area and physician global assessment. The primary outcome was the percentage improvement S-MAPA from course baseline at week 12 of ustekinumab treatment. Secondary outcomes were the psoriasis clearance, primary failure, and secondary failure rates with ustekinumab treatment. Patients with a previous TNFi primary failure had a significantly lower percentage improvement in S-MAPA score at week 12 of ustekinumab treatment compared with patients without TNFi primary failure (36.2% vs 61.1%, P=.027). Multivariate analysis demonstrated that this relationship was independent of patient demographics and medical comorbidities. Patients with multiple TNFi exposures had a non-statistically significant lower percentage S-MAPA improvement at week 12 (40.5% vs 52.9%, P=.294) of ustekinumab treatment compared with patients with a single TNFi exposure. Among psoriasis patients previously exposed to TNFi, a history of a previous TNFi primary failure predicts a decreased response to ustekinumab independent of patient demographics and medical comorbidities.

  3. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

    SciTech Connect

    Duffy, Stephen

    2013-09-09

    This project will implement inelastic constitutive models that will yield the requisite stress-strain information necessary for graphite component design. Accurate knowledge of stress states (both elastic and inelastic) is required to assess how close a nuclear core component is to failure. Strain states are needed to assess deformations in order to ascertain serviceability issues relating to failure, e.g., whether too much shrinkage has taken place for the core to function properly. Failure probabilities, as opposed to safety factors, are required in order to capture the bariability in failure strength in tensile regimes. The current stress state is used to predict the probability of failure. Stochastic failure models will be developed that can accommodate possible material anisotropy. This work will also model material damage (i.e., degradation of mechanical properties) due to radiation exposure. The team will design tools for components fabricated from nuclear graphite. These tools must readily interact with finite element software--in particular, COMSOL, the software algorithm currently being utilized by the Idaho National Laboratory. For the eleastic response of graphite, the team will adopt anisotropic stress-strain relationships available in COMSO. Data from the literature will be utilized to characterize the appropriate elastic material constants.

  4. [Failure Prediction of Power-Shift Steering Transmission Based on Oil Spectral Analysis with Wiener Process].

    PubMed

    Liu, Yong; Ma, Biao; Zheng, Chang-song; Xie, Shang-yu

    2015-09-01

    The most common methodology used in element concentration measurement and analyzing of wear particles is Atomic emission (AE) spectroscopy. As an indirect measuring method, the oil spectral data is introduced to indicate the performance degradation and the residual life prediction in the reliability evaluation of Power shift steering transmission (PSST). Stochastic methods especially the Wiener process is convenient in solving and analyzing the unitary degradation failure indicated by the oil spectral data. The oil data have been sampled in the real operating condition, and the data set has more than 50 samples taken from PSST. The mean values and time-dependent characteristics of three indicating elements are statistically obtained by the linear regression analysis. The model of the degradation and failure prediction has been proposed based on the Wiener process with the positive drift. For modeling and simulation the software R was used. Therefore, the trend curves of diffusion process with their First Hitting Time have been predicted. Through comparison, the time intervals of condition-based maintenance have been extended as 27 Mh (15.9%). This will save the cost of maintenances by eliminate the preventive maintained cycles. The advantage and novelty of the outcomes presented in the article are that the stochastic process might be applied for predicting the degradation failure occurrence and also for optimizing the maintenance intervals and the cost-benefit. As might be expected, the method can be extended to other cases of wear prediction and evaluation in complex mechanical system.

  5. Avionics equipment failure prediction based on genetic programming and grey model

    NASA Astrophysics Data System (ADS)

    Deng, Xiujian; Luo, Qiang; Zhao, Yiyang; Feng, Qi

    2017-01-01

    Avionics equipment failure prediction by conventional GM (Grey Model) may yield large forecasting errors. Combining GM (1, 1) model with genetic programming algorithm, a kind of GP-GM (1, 1) forecast model was established to minimize such errors. Forecasting sequence was calculated by means of GM (1, 1) model, then genetic programming algorithm was used to modify them further, and the degradation trend prediction of characteristic parameters of avionics equipment was realized. The validity of GP-GM (1, 1) prediction model was testified by tracking and forecasting the experiment data of avionics equipment in real environment.

  6. Worsening of Heart Failure after Abdominal Surgery – Can we predict it?

    PubMed Central

    TOMA, Nora; DRAGOI GALRINHO, Ruxandra; BICESCU, Gabriela; ENACHE, Raluca; CINTEZA, Mircea; GHERASIM, Leonida

    2013-01-01

    ABSTRACT Background: The cardiopulmonary test has demonstrated its role in predicting long term prognostic of patients with heart failure, but only few data are available regarding its utility on short term period. Methods: During 2011-2013, the study enrolled 55 patients over 18 years, with different cardiovascular, metabolic and/or pulmonary pathologies, and 10 control patients matched for age, sex and surgical intervention type, without an associated pathological history who underwent elective abdominal surgery with general anesthesia. Results: The most important predictors of the heart failure worsening after abdominal surgery were peak VO2 as percent of predicted VO2 lower than 59.42±12.52, ventilator equivalent for CO2 at anaerobic threshold over 39.53±5.27 and VD/VT ratio at anaerobic threshold over 0.33±0.06. Lean VO2 lower than 9.58±2.47 also correlated with the above mentioned complication. The ventilator equivalent for CO2, above 39.53±5.27 at anaerobic threshold, respectively 40.67±6.73 at peak exercise, correlates with short term worsening of heart failure after general anesthesia for abdominal surgery. Conclusion: The CPX test has a certain value in predicting short term worsening of heart failure after general anesthesia for elective abdominal surgery in patients known with cardiovascular, pulmonary and/or metabolic disorders. PMID:24371475

  7. Venovenous extracorporeal membrane oxygenation in adult respiratory failure: Scores for mortality prediction.

    PubMed

    Hsin, Chun-Hsien; Wu, Meng-Yu; Huang, Chung-Chi; Kao, Kuo-Chin; Lin, Pyng-Jing

    2016-06-01

    Despite a potentially effective therapy for adult respiratory failure, a general agreement on venovenous extracorporeal membrane oxygenation (VV-ECMO) has not been reached among institutions due to its invasiveness and high resource usage. To establish consensus on the timing of intervention, large ECMO organizations have published the respiratory extracorporeal membrane oxygenation survival prediction (RESP) score and the ECMOnet score, which allow users to predict hospital mortality for candidates with their pre-ECMO presentations. This study was aimed to test the predictive powers of these published scores in a medium-sized cohort enrolling adults treated with VV-ECMO for acute respiratory failure, and develop an institutional prediction model under the framework of the 3 scores if a superior predictive power could be achieved. This retrospective study included 107 adults who received VV-ECMO for severe acute respiratory failure (a PaO2/FiO2 ratio <70 mm Hg) in a tertiary referral center from 2007 to 2015. Essential demographic and clinical data were collected to calculate the RESP score, the ECMOnet score, and the sequential organ failure assessment (SOFA) score before VV-ECMO. The predictive power of hospital mortality of each score was presented as the area under receiver-operating characteristic curve (AUROC). The multivariate logistic regression was used to develop an institutional prediction model. The surviving to discharge rate was 55% (n = 59). All of the 3 published scores had a real but poor predictive power of hospital mortality in this study. The AUROCs of RESP score, ECMOnet score, and SOFA score were 0.662 (P = 0.004), 0.616 (P = 0.04), and 0.667 (P = 0.003), respectively. An institutional prediction model was established from these score parameters and presented as follows: hospital mortality (Y) = -3.173 + 0.208 × (pre-ECMO SOFA score) + 0.148 × (pre-ECMO mechanical ventilation day) + 1.021

  8. Direct extubation onto high-flow nasal cannulae post-cardiac surgery versus standard treatment in patients with a BMI ≥30: a randomised controlled trial.

    PubMed

    Corley, Amanda; Bull, Taressa; Spooner, Amy J; Barnett, Adrian G; Fraser, John F

    2015-05-01

    Patients with a body mass index (BMI) ≥30 kg/m(2) experience more severe atelectasis following cardiac surgery than those with normal BMI and its resolution is slower. This study aimed to compare extubation of patients post-cardiac surgery with a BMI ≥30 kg/m(2) onto high-flow nasal cannulae (HFNC) with standard care to determine whether HFNC could assist in minimising post-operative atelectasis and improve respiratory function. In this randomised controlled trial, patients received HFNC or standard oxygen therapy post-extubation. The primary outcome was atelectasis on chest X-ray. Secondary outcomes included oxygenation, respiratory rate (RR), subjective dyspnoea, and failure of allocated treatment. One hundred and fifty-five patients were randomised, 74 to control, 81 to HFNC. No difference was seen between groups in atelectasis scores on Days 1 or 5 (median scores = 2, p = 0.70 and p = 0.15, respectively). In the 24-h post-extubation, there was no difference in mean PaO2/FiO2 ratio (HFNC 227.9, control 253.3, p = 0.08), or RR (HFNC 17.2, control 16.7, p = 0.17). However, low dyspnoea levels were observed in each group at 8 h post-extubation, median (IQR) scores were 0 (0-1) for control and 1 (0-3) for HFNC (p = 0.008). Five patients failed allocated treatment in the control group compared with three in the treatment group [Odds ratio 0.53, (95 % CI 0.11, 2.24), p = 0.40]. In this study, prophylactic extubation onto HFNC post-cardiac surgery in patients with a BMI ≥30 kg/m(2) did not lead to improvements in respiratory function. Larger studies assessing the role of HFNC in preventing worsening of respiratory function and intubation are required.

  9. Bone texture analysis of human femurs using a new device (BMA™) improves failure load prediction.

    PubMed

    Kolta, S; Paratte, S; Amphoux, T; Persohn, S; Campana, S; Skalli, W; Paternotte, S; Argenson, J-N; Bouler, J-M; Gagey, O; Roux, C

    2012-04-01

    We measured bone texture parameters of excised human femurs with a new device (BMA™). We also measured bone mineral density by DXA and investigated the performance of these parameters in the prediction of failure load. Our results suggest that bone texture parameters improve failure load prediction when added to bone mineral density. Bone mineral density (BMD) is a strong determinant of bone strength. However, nearly half of the fractures occur in patients with BMD which does not reach the osteoporotic threshold. In order to assess fracture risk properly, other factors are important to be taken into account such as clinical risk factors as well as macro- and microarchitecture of bone. Bone microarchitecture is usually assessed by high-resolution QCT, but this cannot be applied in routine clinical settings due to irradiation, cost and availability concerns. Texture analysis of bone has shown to be correlated to bone strength. We used a new device to get digitized X-rays of 12 excised human femurs in order to measure bone texture parameters in three different regions of interest (ROIs). We investigated the performance of these parameters in the prediction of the failure load using biomechanical tests. Texture parameters measured were the fractal dimension (Hmean), the co-occurrence matrix, and the run length matrix. We also measured bone mineral density by DXA in the same ROIs as well as in standard DXA hip regions. The Spearman correlation coefficient between BMD and texture parameters measured in the same ROIs ranged from -0.05 (nonsignificant (NS)) to 0.57 (p = 0.003). There was no correlation between Hmean and co-occurrence matrix nor Hmean and run length matrix in the same ROI (r = -0.04 to 0.52, NS). Co-occurrence matrix and run length matrix in the same ROI were highly correlated (r = 0.90 to 0.99, p < 0.0001). Univariate analysis with the failure load revealed significant correlation only with BMD results, not texture parameters. Multiple

  10. Impact and Challenges of a Policy Change to Early Track Extubation in the Operating Room for Fontan.

    PubMed

    Kawaguchi, Atsushi; Liu, Qi; Coquet, Sean; Yasui, Yutaka; Cave, Dominic

    2016-08-01

    hemodynamic instability in the pre-policy-change era (6/39, 15.4 %) and excessive bleeding or respiratory etiologies in the post-policy-change era (10/88, 11.4 %). Significant reduction of PICU length of stay was achieved without any evidence of worsening of patient outcomes. RCA suggests watchful observations with respect to bleeding and respiratory etiologies are the key to prevent failure of extubation in the current practice.

  11. Feasibility of weaning and direct extubation from open lung high-frequency ventilation in preterm infants.

    PubMed

    van Velzen, Alice; De Jaegere, Anne; van der Lee, Johanna; van Kaam, Anton

    2009-01-01

    High-frequency ventilation (HFV) is increasingly used in preterm infants, but data on weaning and extubation are limited. We aimed to establish if weaning the continuous distending pressure (CDP) below 8 cm H2O and the Fio2 below 0.30 is feasible in preterm infants on open lung HFV and if these settings result in successful extubation. Retrospective cohort study. Neonatal intensive care unit in a university hospital. Preterm infants ventilated and directly extubated from HFV between January 2003 and August 2005. Data on patient characteristics, ventilator settings, gas exchange, respiratory support after extubation and the number of patients failing extubation (i.e., reintubation within 48 hr) were retrospectively collected. Two hundred fourteen infants, accounting for 242 ventilation periods, were included in the study. The CDP, but not the Fio2, decreased significantly in the 24-hr period before extubation, resulting in a mean CDP of 6.8 +/- 1.6 cm H2O and a mean Fio2 of 0.25 at the time of extubation. At these settings, 193 (90%) infants were successfully extubated. Multivariate logistic regression analysis showed that birth weight was the only independent variable positively associated with successful extubation. This study shows that weaning the CDP below 8 cm H2O with an Fio2 below 0.30 is feasible during open lung HFV and extubation at these settings can be successful in preterm infants. In our series, a 90% success rate was observed. The value of this approach should be prospectively compared with conventional weaning and extubation strategies.

  12. A randomised controlled trial of two methods of delivering nasal continuous positive airway pressure after extubation to infants weighing less than 1000 g: binasal (Hudson) versus single nasal prongs

    PubMed Central

    Davis, P; Davies, M; Faber, B

    2001-01-01

    OBJECTIVES—Primary: to determine whether nasal continuous positive airway pressure (CPAP) delivered through binasal prongs results in a greater proportion of extremely low birthweight infants being successfully extubated, after a period of intermittent positive pressure ventilation, than nasal CPAP delivered by a single nasal prong. Secondary: to evaluate the effect of mode of delivery of nasal CPAP after extubation on the need for endotracheal reintubation, weight gain, rates of feeding intolerance, sepsis, suspected sepsis, cranial ultrasound abnormalities, retinopathy of prematurity, chronic lung disease, and the duration of assisted ventilation and care in the tertiary neonatal unit.
DESIGN AND SETTING—Randomised, controlled, clinical trial conducted at the neonatal intensive care unit of the Royal Women's Hospital, Melbourne, Australia.
PATIENTS—Infants of birth weight less than 1000 g, ventilated, requiring < 50% oxygen and ventilator rate less than or equal to 20/minute, and considered by the clinical management team to be ready for extubation.
INTERVENTION—Infants were randomly allocated to receive nasal CPAP delivered through binasal (Hudson) prongs or a single nasal prong.
PRIMARY OUTCOME MEASURE—Failure of extubation as defined by the following criteria: (a) apnoea (more than one episode/hour over a six hour period or one episode requiring bag and mask ventilation); (b) absolute increase in oxygen requirement greater than 15% above that required before extubation; (c) respiratory acidosis (pH < 7.25 with PCO2 > 6.67 kPa).
RESULTS—Ten of the 41 (24%) infants randomised to binasal prongs reached predetermined failure criteria compared with 26 of the 46(57%) infants randomised to a single nasal prong (p = 0.005). Four of 17 (24%) infants of birth weight less than 800 g extubated to binasal prongs reached failure criteria compared with 14 of 16 (88%) extubated to a single nasal prong (p < 0.001). There were no significant differences in

  13. Can Failure on Adaptive Locomotor Tasks Independently Predict Incident Mobility Disability?

    PubMed Central

    Deshpande, Nandini; Metter, E. Jeffrey; Guralnik, Jack; Ferrucci, Luigi

    2012-01-01

    This study examined if inability to perform adaptive locomotor tests predicts self-reported incident mobility disability. InCHIANTI study participants (n=611, age: 50–85 years) who could walk 7 m at self-selected speed and had no self-reported mobility disability at baseline were included. Ability to complete 4 adaptive locomotor tests was assessed: fast walking, walking on a narrow path, crossing obstacles while walking and talking while walking. Mobility disability was recorded again at 3-year follow-up. Failure in fast walking and narrow-path walking tests predicted ~2.5 times likelihood of reporting incident mobility disability (p=0.009 and 0.011, respectively). Failure in obstacle crossing test predicted ~2 times likelihood of reporting incident mobility disability, however, this result did not reach statistical significance (p=0.077). Failure in talking while walking did not predict incident mobility disability. Those who failed both fast walking and narrow-path walking tests were almost 9 times as likely to report incident mobility disability. PMID:23291600

  14. Control theory prediction of resolved Cheyne-Stokes respiration in heart failure.

    PubMed

    Sands, Scott A; Edwards, Bradley A; Kee, Kirk; Stuart-Andrews, Christopher; Skuza, Elizabeth M; Roebuck, Teanau; Turton, Anthony; Hamilton, Garun S; Naughton, Matthew T; Berger, Philip J

    2016-11-01

    Cheyne-Stokes respiration (CSR) foretells deleterious outcomes in patients with heart failure. Currently, the size of therapeutic intervention is not guided by the patient's underlying pathophysiology. In theory, the intervention needed to resolve CSR, as a control system instability (loop gain >1), can be predicted knowing the baseline loop gain and how much it falls with therapy.In 12 patients with heart failure, we administered an inspiratory carbon dioxide fraction of 1-3% during CSR (n=95 interventions) as a means to reduce loop gain. We estimated the loop gain on therapy (LGtherapy), using the baseline loop gain (using hyperpnoea length/cycle length) and its expected reduction (18% per 1% inspired carbon dioxide), and tested the specific hypothesis that LGtherapy predicts CSR persistence (LGtherapy >1) versus resolution (LGtherapy <1).As predicted, when LGtherapy >1.0, CSR continued during therapy in 23 out of 25 (92%) trials. A borderline loop gain zone (0.8predictive insight into CSR resolution in heart failure. Thus, we now have a means to calculate the size of interventions needed to ameliorate CSR on a patient-by-patient basis.

  15. Can failure on adaptive locomotor tasks independently predict incident mobility disability?

    PubMed

    Deshpande, Nandini; Metter, E Jeffrey; Guralnik, Jack; Ferrucci, Luigi

    2013-08-01

    This study examined whether inability to perform adaptive locomotor tests predicts self-reported incident mobility disability. InCHIANTI study participants (N = 611; age, 50-85 yrs) who could walk 7 m at self-selected speed and who had no self-reported mobility disability at baseline were included. The ability to complete four adaptive locomotor tests was assessed: fast walking, walking on a narrow path, crossing obstacles while walking, and talking while walking. Mobility disability was recorded again at 3-yr follow-up. Failure in the fast-walking and narrow-path walking tests predicted approximately 2.5 times likelihood of reporting incident mobility disability (P = 0.009 and P = 0.011, respectively). Failure in the obstacle-crossing test predicted approximately two times likelihood of reporting incident mobility disability; however, this result did not reach statistical significance (P = 0.077). Failure in talking while walking did not predict incident mobility disability. Those who failed both the fast-walking and narrow-path walking tests were almost nine times as likely to report incident mobility disability.

  16. Predicting remaining life by fusing the physics of failure modeling with diagnostics

    NASA Astrophysics Data System (ADS)

    Kacprzynski, G. J.; Sarlashkar, A.; Roemer, M. J.; Hess, A.; Hardman, B.

    2004-03-01

    Technology that enables failure prediction of critical machine components (prognostics) has the potential to significantly reduce maintenance costs and increase availability and safety. This article summarizes a research effort funded through the U.S. Defense Advanced Research Projects Agency and Naval Air System Command aimed at enhancing prognostic accuracy through more advanced physics-of-failure modeling and intelligent utilization of relevant diagnostic information. H-60 helicopter gear is used as a case study to introduce both stochastic sub-zone crack initiation and three-dimensional fracture mechanics lifing models along with adaptive model updating techniques for tuning key failure mode variables at a local material/damage site based on fused vibration features. The overall prognostic scheme is aimed at minimizing inherent modeling and operational uncertainties via sensed system measurements that evolve as damage progresses.

  17. Prediction of failure envelopes of composite tubes subjected to biaxial loadings

    NASA Astrophysics Data System (ADS)

    Gargiulo, C.; Marchetti, M.; Rizzo, A.

    1996-09-01

    Practical cylindrical structures including pressure vessels, pipes, drive shafts and rochet motors are usually subjected to complex loads involving biaxial or triaxial stress systems. In particular, filamentary composite vessels are used in applications of Space Shuttle tankage, as well as for the storage of fluids in various commercial applications. The object of this work is to provide numerical and experiment data on the strength of filament wound carbon fibre reinforced epoxy resin thin tubes under biaxial loading conditions. Internal or external pressure and axial loads are applied simultaneously to produce a variety of biaxial stress conditions. The effects of the winding angle of the fibre reinforcements on the failure loads of the pipes have been examined. Finite elements and thin shell analysis have been applied to the problem using different failure criteria in order to predict the specimen's failure for a comparison with experimental results.

  18. Qualitative and semiquantitative polymerase chain reaction to predict Plasmodium falciparum treatment failure.

    PubMed

    Kain, K C; Kyle, D E; Wongsrichanalai, C; Brown, A E; Webster, H K; Vanijanonta, S; Looareesuwan, S

    1994-12-01

    Multidrug-resistant falciparum malaria is increasing in most malaria-endemic areas. Rapid methods for predicting treatment failure would aid management and control of drug-resistant infections. In this study, Plasmodium falciparum DNA clearance was examined by qualitative and semiquantitative polymerase chain reaction (PCR). Thai patients with acute falciparum malaria were prospectively followed by light microscopy and by PCR of P. falciparum DNA eluted from filter paper blood samples. A 206-bp P. falciparum sequence was amplified and detected radiometrically and by high-performance liquid chromatography. Clearance of P. falciparum DNA was significantly delayed in treatment failures compared with that in successfully treated patients (P = .02). Semiquantitative PCR levels did not drop to < 50% of pretreatment levels until day 3 or later in treatment failures compared with day 1 or earlier for successfully treated parasitemia-matched controls (P = .005). These results suggest that qualitative and semiquantitative PCR may be useful as a method for monitoring response to therapy.

  19. Predicting in vivo failure of rotary nickel-titanium endodontic instruments under cyclic fatigue.

    PubMed

    Stojanac, Igor; Drobac, Milan; Petrovic, Ljubomir; Atanackovic, Teodor

    2012-01-01

    The aim of this study was to examine the lifespan or number of cycles to failure of tapered rotary nickel-titanium (Ni-Ti) endodontic instruments. Simulated root canals with different curvatures were used to determine a relation between canal curvature and instrument lifespan. Using a novel mathematical model for the deformation of pseudoelastic Ni-Ti alloy, it was shown that maximum stress need not necessarily occur at the outer layer. On the basis of this observation, the Coffin-Manson relation was modified with parameters determined from this experiment. Results showed that the number of cycles to failure was influenced by the angle and radius of canal curvature and the size of instrument at the beginning of canal curvature. The resulting quantitative mathematical relation could be used to predict the lifespan of rotary Ni-Ti endodontic instruments under clinical conditions and thereby reduce the incidence of instrument failure in vivo.

  20. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method.

    PubMed

    Alani, Amir M; Faramarzi, Asaad

    2015-06-10

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes.

  1. Acute liver failure in Japan: definition, classification, and prediction of the outcome.

    PubMed

    Sugawara, Kayoko; Nakayama, Nobuaki; Mochida, Satoshi

    2012-08-01

    Acute liver failure is a clinical syndrome characterized by hepatic encephalopathy and a bleeding tendency due to severe impairment of liver function caused by massive or submassive liver necrosis. Viral hepatitis is the most important and frequent cause of acute liver failure in Japan. The diagnostic criteria for fulminant hepatitis, including that caused by viral infections, autoimmune hepatitis, and drug allergy induced-liver damage, were first established in 1981. Considering the discrepancies between the definition of fulminant hepatitis in Japan and the definitions of acute liver failure in the United States and Europe, the Intractable Hepato-Biliary Disease Study Group established the diagnostic criteria for "acute liver failure" for Japan in 2011, and performed a nationwide survey of patients seen in 2010 to clarify the demographic and clinical features and outcomes of these patients. According to the survey, the survival rates of patients receiving medical treatment alone were low, especially in those with hepatic encephalopathy, despite artificial liver support, consisting of plasma exchange and hemodiafiltration, being provided to almost all patients in Japan. Thus, liver transplantation is inevitable to rescue most patients with hepatic encephalopathy. The indications for liver transplantation had, until recently, been determined according to the guideline published by the Acute Liver Failure Study Group in 1996. Recently, however, the Intractable Hepato-Biliary Disease Study Group established a scoring system to predict the outcomes of acute liver failure patients. Algorithms for outcome prediction have also been developed based on data-mining analyses. These novel guidelines need further evaluation to determine their usefulness.

  2. Liver stiffness measurement predicts high-grade post-hepatectomy liver failure: A prospective cohort study.

    PubMed

    Chong, Charing Ching-Ning; Wong, Grace Lai-Hung; Chan, Anthony Wing-Hung; Wong, Vincent Wai-Sun; Fong, Anthony Kwong-Wai; Cheung, Yue-Sun; Wong, John; Lee, Kit-Fai; Chan, Stephen L; Lai, Paul Bo-San; Chan, Henry Lik-Yuen

    2017-02-01

    Liver stiffness measurement using transient elastography appears to be an excellent tool for detection of liver fibrosis and cirrhosis with high accuracy. The aim of this study is to evaluate the efficacy of preoperative liver stiffness measurement in predicting post-hepatectomy liver failure. A prospective cohort study of all consecutive patients undergoing hepatectomy for hepatocellular carcinoma from February 2010 to August 2014 was studied. All patients received detailed preoperative assessments including liver stiffness measurement. The primary outcome was post-hepatectomy liver failure according to the International Study Group of Liver Surgery definition. A total of 255 patients were included. Liver stiffness measurement showed significant correlation with grade B or C post-hepatectomy liver failure. (P = 0.003) Using the cutoff at 12 kPa, liver stiffness measurement had a sensitivity of 52.4% and specificity of 73.3% in predication of high-grade (grade B or C) post-hepatectomy liver failure. Liver stiffness measurement > 12 kPa was also an independent prognostic factor for both high-grade post-hepatectomy liver failure and major postoperative complications by multivariate analysis. The diagnostic accuracy was better in patients without right lobe tumor with an area under the receiver operating characteristic of 0.83 compared with an area under the receiver operating characteristic of only 0.62 in patients with right lobe tumor. Liver stiffness measurement using Fibroscan is good to predict high-grade post-hepatectomy liver failure especially in patients without right lobe tumor. © 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

  3. Treatment failure prediction for head-and-neck cancer radiation therapy.

    PubMed

    Rocha, H; Khouri, L; Lopes, M C; Dias, J; Ferreira, B

    2016-06-01

    Treatment outcome prediction is an important emerging topic in oncologic care. To support radiation oncologists on their decisions, with individualized, tailored treatment regimens increasingly becoming the standard of care, accurate tools to predict tumour response to treatment are needed. The goal of this work is to identify the most determinant factor(s) for treatment response aiming to develop prediction models that robustly estimate tumour response to radiation therapy in patients with head-and-neck cancer. A population-based cohort study was performed on 92 patients with head-and-neck cancer treated with radiation from 2007 until 2014 at the Portuguese Institute of Oncology of Coimbra (IPOCFG). Correlation analysis and multivariate binary logistic regression analysis were conducted in order to explore the predictive power of the considered predictors. Performance of the models is expressed as the area under the curve (AUC) of the receiver operating characteristics (ROC) curve. A nomogram to predict treatment failure was developed. Significant prognostic factors for treatment failure, after multivariate regression, were older age, non-concomitant radiation therapy and larger primary tumour volume. A regression model with these predictors revealed an AUC of .78 for an independent data set. For patients with head-and-neck cancer treated with definitive radiation, we have developed a prediction nomogram based on models that presented good discriminative ability in making predictions of tumour response to treatment. The probability of treatment failure is higher for older patients with larger tumours treated with non-concomitant radiation. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  4. Predicting Renal Failure Progression in Chronic Kidney Disease Using Integrated Intelligent Fuzzy Expert System.

    PubMed

    Norouzi, Jamshid; Yadollahpour, Ali; Mirbagheri, Seyed Ahmad; Mazdeh, Mitra Mahdavi; Hosseini, Seyed Ahmad

    2016-01-01

    Chronic kidney disease (CKD) is a covert disease. Accurate prediction of CKD progression over time is necessary for reducing its costs and mortality rates. The present study proposes an adaptive neurofuzzy inference system (ANFIS) for predicting the renal failure timeframe of CKD based on real clinical data. This study used 10-year clinical records of newly diagnosed CKD patients. The threshold value of 15 cc/kg/min/1.73 m(2) of glomerular filtration rate (GFR) was used as the marker of renal failure. A Takagi-Sugeno type ANFIS model was used to predict GFR values. Variables of age, sex, weight, underlying diseases, diastolic blood pressure, creatinine, calcium, phosphorus, uric acid, and GFR were initially selected for the predicting model. Weight, diastolic blood pressure, diabetes mellitus as underlying disease, and current GFR(t) showed significant correlation with GFRs and were selected as the inputs of model. The comparisons of the predicted values with the real data showed that the ANFIS model could accurately estimate GFR variations in all sequential periods (Normalized Mean Absolute Error lower than 5%). Despite the high uncertainties of human body and dynamic nature of CKD progression, our model can accurately predict the GFR variations at long future periods.

  5. Cognitive Failure and Alexithymia and Predicting High–Risk Behaviors of Students With Learning Disabilities

    PubMed Central

    Abbasi, Moslem; Bagyan, Mohammad Javad; Dehghan, Hamidreza

    2014-01-01

    Background: One of the threatening health issues is prevalence of high-risk behaviors in various groups. Because of rapid social changes, it has been considered as of the most important problems of society by health organizations, administrative laws, and social policymakers. Objectives: The aim of this study was to determine the role of cognitive failure and alexithymia in predicting high-risk behaviors of students with learning disabilities. Patients and Methods: This was a correlational research including all 14-16 years old students during 2012-2013 school year in Arak, IR Iran. Eighty students with learning disabilities were sampled by simply random sampling. The data were collected by cognitive failures questionnaire, Toronto alexithymia scale, and high-risk behavior questionnaire. Results: The results showed that high-risk behaviors had significant positive correlations with difficulty identifying feelings (r = 0.321), difficulty describing feelings (r = 0.336), externally oriented thinking (r = 0.248), distractibility (0.292), memory distortion (r = 0.374), blunders (r = 0.335), and names amnesia (r = 0.275). Multiple regression analysis showed that cognitive failure and alexithymia predicted 32% of the total variance of high-risk behaviors. Conclusions: These findings demonstrated that cognitive failure and alexithymia had important roles in strengthening and appearance of high-risk behaviors in students with learning disabilities. Therefore, considering those problems, precautionary actions might be necessary. PMID:25032160

  6. Coronary flow reserve assessed by myocardial contrast echocardiography predicts mortality in patients with heart failure.

    PubMed

    Anantharam, Brijesh; Janardhanan, Raj; Hayat, Sajad; Hickman, Michael; Chahal, Navtej; Bassett, Paul; Senior, Roxy

    2011-01-01

    the aim of the study was to assess whether myocardial contrast echocardiography (MCE) can predict mortality in patients with heart failure. Myocardial viability, ischaemia, and coronary flow reserve (CFR) are predictors of mortality in patients with heart failure. MCE can assess myocardial viability, ischaemia, and CFR at the bedside. However, its prognostic value is unknown in patients with heart failure. eighty-seven patients (age: 68 ± 10 years, 62% male) with heart failure [left ventricular ejection fraction (LVEF): 35% ± 13] underwent low-power intermittent MCE at rest and 2 min after dipyridamole infusion. Resting and stress perfusion score index were derived qualitatively. CFR (MBF at stress/MBF at rest) was calculated by a quantitative method. All patients underwent coronary arteriography. Patients were followed up for mortality. Of the 87 patients, 43 (49%) patients had coronary artery disease. There were 28 (32%) deaths during a mean follow-up of 4.1 ± 1.7 years. Type 2 diabetes [P = 0.02, hazard ratios (HR) 2.43, confidence interval (CI) 1.13-5.22] and CFR (P = 0.001, HR 0.15, CI 0.05-0.45) were independent predictors of mortality. A CFR ≤ 1.5 had a significantly (P < 0.0001) higher mortality of 49 vs. 10% in patients with CFR > 1.5 over the 4 year follow-up period. CFR determined by MCE is a powerful predictor of mortality in patients with heart failure.

  7. Distinguishing and predicting granular failure via multiscale evolution of contact cycle topologies

    NASA Astrophysics Data System (ADS)

    Pucilowski, Sebastian; Walker, David M.; Tordesillas, Antoinette

    2013-06-01

    We examine the spatial evolution of 3-cycle topologies in the contact networks of 2D and 3D granular media under load experiencing one of two modes of failure at the macroscopic scale: diffused or localised. These mesoscale structures encapsulate kinematical signatures of plastic deformation and thus their destruction or deaths provides a means of tracking or predicting macroscopic failure. A multiscale point pattern analysis quantifies the extent of spatial clustering of these structures within the material throughout loading. In samples undergoing failure through strain localisation, 3-cycle deaths exhibit evidence for spatial clustering well before peak shear stress and shear band nucleation. Detection occurs earlier in the loading history compared to more traditional soil mechanics measures, e.g., porosity maps and particle rotations. Moreover the region of strain localisation is delineated by the spatial distribution of the dying 3-cycle contact topologies. In samples undergoing diffuse failure, no evidence of localisation is detected over short strain intervals suggesting an optimal window size to capture key kinematics, with an aim towards using the spatial behaviour of mesoscopic 3-cycles as a tool to classify macroscopic failure modes.

  8. A relation to predict the failure of materials and potential application to volcanic eruptions and landslides

    PubMed Central

    Hao, Shengwang; Liu, Chao; Lu, Chunsheng; Elsworth, Derek

    2016-01-01

    A theoretical explanation of a time-to-failure relation is presented, with this relationship then used to describe the failure of materials. This provides the potential to predict timing (tf − t) immediately before failure by extrapolating the trajectory as it asymptotes to zero with no need to fit unknown exponents as previously proposed in critical power law behaviors. This generalized relation is verified by comparison with approaches to criticality for volcanic eruptions and creep failure. A new relation based on changes with stress is proposed as an alternative expression of Voight’s relation, which is widely used to describe the accelerating precursory signals before material failure and broadly applied to volcanic eruptions, landslides and other phenomena. The new generalized relation reduces to Voight’s relation if stress is limited to increase at a constant rate with time. This implies that the time-derivatives in Voight’s analysis may be a subset of a more general expression connecting stress derivatives, and thus provides a potential method for forecasting these events. PMID:27306851

  9. Predicting and preventing peripheral intravenous cannula insertion failure in the emergency department: Clinician 'gestalt' wins again.

    PubMed

    Rippey, James Cr; Carr, Peter J; Cooke, Marie; Higgins, Niall; Rickard, Claire M

    2016-12-01

    Failed attempts at peripheral i.v. cannula (PIVC) insertion in the ED are common. The psychological, physical and economic impact of these failures is significant. We sought to explore whether clinicians of differing experience levels can predict their own likelihood (clinician 'gestalt') of first-time cannula insertion success on any given patient. Data analyses from a prospective self-reported study assessing risk factors for first-time insertion success in a tertiary adult ED. We constructed and compared two simple theoretical clinical decision algorithms in an attempt to improve first-time PIVC insertion success rates. This best algorithm identified a subgroup of 18% of the total PIVC population at higher risk of failure. This 18% comprised 57% of all PIVC failures, and implementation would result in a relative risk reduction of PIVC failure by 31%. When applied to our sample population, an algorithm relying on clinician gestalt to identify patients at high risk of PIVC failure had the greatest potential impact. These patients would be referred to expert PIVC inserters prior to, rather than after, failed attempts. © 2016 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  10. A relation to predict the failure of materials and potential application to volcanic eruptions and landslides.

    PubMed

    Hao, Shengwang; Liu, Chao; Lu, Chunsheng; Elsworth, Derek

    2016-06-16

    A theoretical explanation of a time-to-failure relation is presented, with this relationship then used to describe the failure of materials. This provides the potential to predict timing (tf - t) immediately before failure by extrapolating the trajectory as it asymptotes to zero with no need to fit unknown exponents as previously proposed in critical power law behaviors. This generalized relation is verified by comparison with approaches to criticality for volcanic eruptions and creep failure. A new relation based on changes with stress is proposed as an alternative expression of Voight's relation, which is widely used to describe the accelerating precursory signals before material failure and broadly applied to volcanic eruptions, landslides and other phenomena. The new generalized relation reduces to Voight's relation if stress is limited to increase at a constant rate with time. This implies that the time-derivatives in Voight's analysis may be a subset of a more general expression connecting stress derivatives, and thus provides a potential method for forecasting these events.

  11. Prediction of Thromboembolic Events in Heart Failure Patients in Sinus Rhythm: The Hong Kong Heart Failure Registry

    PubMed Central

    Hai, Jo-Jo; Chan, Pak-Hei; Chan, Yap-Hang; Fong, Carol-Ho-Yi; Huang, Duo; Li, Wen-Hua; Yin, Li-Xue; Lau, Chu-Pak; Tse, Hung-Fat; Siu, Chung-Wah

    2016-01-01

    Aim Heart failure (HF) increases the risk of thromboembolic events (TE). Study in a Caucasian population has shown that the CHA2DS2-VASc score predicts TE among HF patients without atrial fibrillation. We sought to assess the usefulness of the CHA2DS2-VASc score in predicting TE in an Asian population and refine the scoring system to improve its predictability of TE among HF patients in sinus rhythm. Methods A total of 1,202 consecutive patients who were admitted to our institution for new-onset HF from 2005 to 2012 and without atrial fibrillation or anticoagulation were retrospectively reviewed. Results The mean age was 77.6 ± 12.2 years and 51.7% were female. After 36.2 ± 30.1 months, 113 (9.4%) developed TE. The annual incidence was 0.54%, 1.54%, 2.98% and 5.04% per year in those who had a CHA2DS2-VASc score of 1, 2–3, 4–5 and ≥6, respectively. In multivariate analysis, age ≥75 years [Hazard ratio (HR) 2.59, 95% confidence interval (CI) 1.23–5.46, p = 0.012), chronic ischemic heart disease (HR 1.54, 95% CI 1.02–2.31, p = 0.040) and chronic kidney disease (HR 1.66, 95% CI 1.09–2.53, p = 0.018) independently predicted TE. Incorporation of chronic ischemic heart disease and chronic kidney disease into the CHA2DS2-VASc score significantly increased the area under the Receiver Operating Curve from 0.57 (95% CI 0.54–0.59) to 0.61 (95% CI 0.55–0.66; p = 0.022). Conclusion The CHA2DS2-VASc score is useful for stratification of the risk of TE among HF patients in sinus rhythm. Incorporation of chronic ischemic heart disease and chronic kidney disease into the score modestly improves its predictive value. PMID:28036365

  12. Early Subsidence Predicts Failure of a Cemented Femoral Stem With Minor Design Changes.

    PubMed

    Johanson, Per-Erik; Antonsson, Martin; Shareghi, Bita; Kärrholm, Johan

    2016-10-01

    Radiostereometry (RSA) measurements of early micromotion can predict later failure in hip and knee prostheses. In hip implants, RSA has been particularly helpful in the evaluation of composite-beam stem designs. The Spectron EF Primary stem (Smith & Nephew, London, UK) has shown inferior performance compared with its predecessors in both clinical studies and registry reports. Early RSA studies have shown somewhat greater subsidence for the Spectron EF Primary stem compared with the earlier Spectron EF, but still within boundaries considered to be safe. Our primary research question was whether stem subsidence and rotation for this stem design measured with RSA at 2 years can predict later stem failure. A secondary question was whether high femoral stem offset and small stem sizes, both features specific to the Spectron EF Primary stem compared with its predecessors, are associated with stem failure rate. Two hundred forty-seven hips (209 patients with median age 63 years [range, 29-80 years], 65% female, and 77% primary osteoarthritis) with a valid RSA examination at 2 years were selected from four different RSA studies (totaling 279 hips in 236 patients) in our department. The studies were primarily aimed at evaluating cup fixation, bone cement, and polyethylene types. All study patients received a cemented Spectron EF Primary stem. The selected hips had complete followup until stem failure, death, or the end of the followup period. Stem failure was defined as revision of a loose femoral stem or radiological failure with significant osteolysis in Gruen zones 2 to 6. Cox regression analyses were performed to evaluate if stem subsidence and rotation after 2 years, adjusted for age, sex, stem size, standard/high stem offset, and conventional/highly crosslinked polyethylene, could predict later clinical aseptic failure of the stem. We identified 32 stem failures (27 revisions, five radiological failures) at 14 years median followup (range, 3-18 years). Ten-year stem

  13. In vitro/in silico investigation of failure criteria to predict flexural strength of composite resins.

    PubMed

    Yamaguchi, Satoshi; Mehdawi, Idris Mohamed; Sakai, Takahiko; Abe, Tomohiro; Inoue, Sayuri; Imazato, Satoshi

    2017-09-28

    The aim of this study was to investigate a failure criterion to predict flexural strengths of composite resins (CR) by three-dimensional finite element analysis (3D-FEA). Models of flexural strength for test specimens of CR and rods comprising a three-point loading were designed. Calculation of Young's moduli and Poisson's ratios of CR were conducted using a modified McGee-McCullough model. Using the experimental CR, flexural strengths were measured by three-point bending tests with crosshead speed 1.0 mm/min and compared with the values determined by in silico analysis. The flexural strengths of experimental CR calculated using the maximum principal strain significantly correlated with those obtained in silico amongst the four types of failure criteria applied. The in silico analytical model established in this study was found to be effective to predict the flexural strengths of CR incorporating various silica filler contents by maximum principal strain.

  14. Preoperative prediction of failure following two-stage revision for knee prosthetic joint infections.

    PubMed

    Sabry, Fady Youssef; Buller, Leonard; Ahmed, Sarim; Klika, Alison K; Barsoum, Wael K

    2014-01-01

    While two-stage revision is the gold standard for treatment of knee prosthetic joint infection (PJI), it is not without risk. The purpose of this study was to develop a tool to preoperatively predict the probability that a two-stage revision would fail to eradicate knee PJI. 3,809 surgical cases were retrospectively reviewed and data were collected from 314 charts. Overall, 105 (33.4%) cases failed to eradicate PJI using this procedure. Univariate analysis identified multiple variables independently associated with reinfection. Logistic regression was used to generate a model (bootstrap-corrected concordance index of 0.773) predicting failure of infection eradication. Preoperative knowledge of a high probability of failure may improve risk assessment, lead to more aggressive management, and allow for time to consider alternative therapies.

  15. A simple nonlocal damage model for predicting failure of notched laminates

    NASA Technical Reports Server (NTRS)

    Kennedy, T. C.; Nahan, M. F.

    1995-01-01

    The ability to predict failure loads in notched composite laminates is a requirement in a variety of structural design circumstances. A complicating factor is the development of a zone of damaged material around the notch tip. The objective of this study was to develop a computational technique that simulates progressive damage growth around a notch in a manner that allows the prediction of failure over a wide range of notch sizes. This was accomplished through the use of a relatively simple, nonlocal damage model that incorporates strain-softening. This model was implemented in a two-dimensional finite element program. Calculations were performed for two different laminates with various notch sizes under tensile loading, and the calculations were found to correlate well with experimental results.

  16. Liver resection for cancer: New developments in prediction, prevention and management of postresectional liver failure.

    PubMed

    van Mierlo, Kim M C; Schaap, Frank G; Dejong, Cornelis H C; Olde Damink, Steven W M

    2016-12-01

    Hepatic failure is a feared complication that accounts for up to 75% of mortality after extensive liver resection. Despite improved perioperative care, the increasing complexity and extensiveness of surgical interventions, in combination with an expanding number of resections in patients with compromised liver function, still results in an incidence of postresectional liver failure (PLF) of 1-9%. Preventive measures aim to enhance future remnant liver size and function. Numerous non-invasive techniques to assess liver function and predict remnant liver volume are being developed, along with introduction of novel surgical strategies that augment growth of the future remnant liver. Detection of PLF is often too late and treatment is primarily symptomatic. Current therapeutic research focuses on ([bio]artificial) liver function support and regenerative medicine. In this review we discuss the current state and new developments in prediction, prevention and management of PLF, in light of novel insights into the aetiology of this complex syndrome.

  17. A cellular solid criterion for predicting the axial-shear failure properties of bovine trabecular bone.

    PubMed

    Fenech, C M; Keaveny, T M

    1999-08-01

    In a long-term effort to develop a complete multi-axial failure criterion for human trabecular bone, the overall goal of this study was to compare the ability of a simple cellular solid mechanistic criterion versus the Tsai-Wu, Principal Strain, and von Mises phenomenological criteria--all normalized to minimize effects of interspecimen heterogeneity of strength--to predict the on-axis axial-shear failure properties of bovine trabecular bone. The Cellular Solid criterion that was developed here assumed that vertical trabeculae failed due to a linear superposition of axial compression/tension and bending stresses, induced by the apparent level axial and shear loading, respectively. Twenty-seven bovine tibial trabecular bone specimens were destructively tested on-axis without end artifacts, loaded either in combined tension-torsion (n = 10), compression-torsion (n = 11), or uniaxially (n = 6). For compression-shear, the mean (+/- S.D.) percentage errors between measured values and criterion predictions were 7.7 +/- 12.6 percent, 19.7 +/- 23.2 percent, 22.8 +/- 18.9 percent, and 82.4 +/- 64.5 percent for the Cellular Solid, Tsai-Wu, Principal Strain, and von Mises criteria, respectively; corresponding mean errors for tension-shear were -5.2 +/- 11.8 percent, 14.3 +/- 12.5 percent, 6.9 +/- 7.6 percent, and 57.7 +/- 46.3 percent. Statistical analysis indicated that the Cellular Solid criterion was the best performer for compression-shear, and performed as well as the Principal Strain criterion for tension-shear. These data should substantially improve the ability to predict axial-shear failure of dense trabecular bone. More importantly, the results firmly establish the importance of cellular solid analysis for understanding and predicting the multiaxial failure behavior of trabecular bone.

  18. A one-year mortality clinical prediction rule for patients with heart failure.

    PubMed

    Escobar, Antonio; García-Pérez, Lidia; Navarro, Gemma; Bilbao, Amaia; Quiros, Raul

    2017-06-19

    To create and validate a clinical prediction rule which is easy to manage, reproducible and that allows classifying patients admitted for heart failure according to their one-year mortality risk. A prospective cohort study carried out with 2565 consecutive patients admitted with heart failure in 13 hospitals in Spain. The derivation cohort was made up of 1283 patients and 1282 formed the validation cohort. In the derivation cohort, we carried out a multivariate logistic model to predict one-year mortality. The performance of the derived predictive risk score was externally validated in the validation cohort, and internally validated by K-fold cross-validation. The risk score was categorized into four risk levels. The mean age was 77.2years, 49.7% were female and there were 611 (23.8%) deaths in the follow-up period. The variables included in the predictive model were: age≥75, systolic blood pressure<135, New York Heart Association class III-IV, heart valve disease, dementia, prior hospitalization, haemoglobin<13, sodium<136, urea≥86, length of stay≥14 and Physical dimension of Minnesota Living with Heart Failure questionnaire. The AUC for the risk score were 0.73 and 0.70 in the derivation and validation cohorts, respectively, and 0.73 in the K-fold cross-validation. The percentage of mortality ranged from 8.08% in the low-risk to 58.20% in the high-risk groups (p<0.0001; AUC, 0.72). This model based on routinely available data, for admitted patients and with a follow-up at one year is a simple and easy-to-use tool for improving management of patients with heart failure. Copyright © 2017 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  19. Effect and clinical prediction of worsening renal function in acute decompensated heart failure.

    PubMed

    Breidthardt, Tobias; Socrates, Thenral; Noveanu, Markus; Klima, Theresia; Heinisch, Corinna; Reichlin, Tobias; Potocki, Mihael; Nowak, Albina; Tschung, Christopher; Arenja, Nisha; Bingisser, Roland; Mueller, Christian

    2011-03-01

    We aimed to establish the prevalence and effect of worsening renal function (WRF) on survival among patients with acute decompensated heart failure. Furthermore, we sought to establish a risk score for the prediction of WRF and externally validate the previously established Forman risk score. A total of 657 consecutive patients with acute decompensated heart failure presenting to the emergency department and undergoing serial creatinine measurements were enrolled. The potential of the clinical parameters at admission to predict WRF was assessed as the primary end point. The secondary end point was all-cause mortality at 360 days. Of the 657 patients, 136 (21%) developed WRF, and 220 patients had died during the first year. WRF was more common in the nonsurvivors (30% vs 41%, p = 0.03). Multivariate regression analysis found WRF to independently predict mortality (hazard ratio 1.92, p <0.01). In a single parameter model, previously diagnosed chronic kidney disease was the only independent predictor of WRF and achieved an area under the receiver operating characteristic curve of 0.60. After the inclusion of the blood gas analysis parameters into the model history of chronic kidney disease (hazard ratio 2.13, p = 0.03), outpatient diuretics (hazard ratio 5.75, p <0.01), and bicarbonate (hazard ratio 0.91, p <0.01) were all predictive of WRF. A risk score was developed using these predictors. On receiver operating characteristic curve analysis, the Forman and Basel prediction rules achieved an area under the curve of 0.65 and 0.71, respectively. In conclusion, WRF was common in patients with acute decompensated heart failure and was linked to significantly worse outcomes. However, the clinical parameters failed to adequately predict its occurrence, making a tailored therapy approach impossible.

  20. Hybrid neural intelligent system to predict business failure in small-to-medium-size enterprises.

    PubMed

    Borrajo, M Lourdes; Baruque, Bruno; Corchado, Emilio; Bajo, Javier; Corchado, Juan M

    2011-08-01

    During the last years there has been a growing need of developing innovative tools that can help small to medium sized enterprises to predict business failure as well as financial crisis. In this study we present a novel hybrid intelligent system aimed at monitoring the modus operandi of the companies and predicting possible failures. This system is implemented by means of a neural-based multi-agent system that models the different actors of the companies as agents. The core of the multi-agent system is a type of agent that incorporates a case-based reasoning system and automates the business control process and failure prediction. The stages of the case-based reasoning system are implemented by means of web services: the retrieval stage uses an innovative weighted voting summarization of self-organizing maps ensembles-based method and the reuse stage is implemented by means of a radial basis function neural network. An initial prototype was developed and the results obtained related to small and medium enterprises in a real scenario are presented.

  1. Prediction of failure in notched carbon-fibre-reinforced-polymer laminates under multi-axial loading.

    PubMed

    Tan, J L Y; Deshpande, V S; Fleck, N A

    2016-07-13

    A damage-based finite-element model is used to predict the fracture behaviour of centre-notched quasi-isotropic carbon-fibre-reinforced-polymer laminates under multi-axial loading. Damage within each ply is associated with fibre tension, fibre compression, matrix tension and matrix compression. Inter-ply delamination is modelled by cohesive interfaces using a traction-separation law. Failure envelopes for a notch and a circular hole are predicted for in-plane multi-axial loading and are in good agreement with the observed failure envelopes from a parallel experimental study. The ply-by-ply (and inter-ply) damage evolution and the critical mechanisms of ultimate failure also agree with the observed damage evolution. It is demonstrated that accurate predictions of notched compressive strength are obtained upon employing the band broadening stress for microbuckling, highlighting the importance of this damage mode in compression. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'. © 2016 The Author(s).

  2. Baroreflex sensitivity might predict responders to milrinone in patients with heart failure.

    PubMed

    Kishi, Takuya; Sunagawa, Kenji

    2010-01-01

    The phosphodiesterase III inhibitor milrinone (MIL) is considered to be effective for "wet and cold" heart failure. In some cases, however, the inotropic effects of milrinone are insufficient. A previous study suggested that baroreflex sensitivity (BRS) predicts the cases in which MIL increases left ventricular dp/dt. The aim of this study was to determine whether BRS measured using the spontaneous sequence method predicts the MIL responders. Twenty-four patients with "wet and cold" heart failure whose systolic blood pressure > 100 mmHg were enrolled. At 2 hours MIL improved dys-pnea, general fatigue, urine volume, and tricuspid regurgitant pressure gradient in 13 patients (responders; R group), whereas it failed to improve in 11 patients (nonresponders; NR group). BRS in the R group was significantly higher than that in the NR group prior to the MIL infusion. At 2 hours after the MIL infusion, BRS was further increased in the R group, but did not increase in the NR group. The sensitivity and specificity of BRS at a cut-off level of 5 ms/mmHg for the prediction of R group were 0.94 and 0.93, respectively. BRS might be useful for identifying potential responders to milrinone in patients with blood pressure-preserved "wet and cold" heart failure.

  3. Failure of Tube Models to Predict the Linear Rheology of Star/Linear Blends

    NASA Astrophysics Data System (ADS)

    Hall, Ryan; Desai, Priyanka; Kang, Beomgoo; Katzarova, Maria; Huang, Qifan; Lee, Sanghoon; Chang, Taihyun; Venerus, David; Mays, Jimmy; Schieber, Jay; Larson, Ronald

    We compare predictions of two of the most advanced versions of the tube model, namely the Hierarchical model by Wang et al. (J. Rheol. 54:223, 2010) and the BOB (branch-on-branch) model by Das et al. (J. Rheol. 50:207-234, 2006), against linear viscoelastic data on blends of monodisperse star and monodisperse linear polybutadiene polymers. The star was carefully synthesized/characterized by temperature gradient interaction chromatography, and rheological data in the high frequency region were obtained through time-temperature superposition. We found massive failures of both the Hierarchical and BOB models to predict the terminal relaxation behavior of the star/linear blends, despite their success in predicting the rheology of the pure star and pure linear. This failure occurred regardless of the choices made concerning constraint release, such as assuming arm retraction in fat or skinny tubes, or allowing for disentanglement relaxation to cut off the constraint release Rouse process at long times. The failures call into question whether constraint release can be described as a combination of constraint release Rouse processes and dynamic tube dilation within a canonical tube model of entanglement interactions.

  4. Tension Strength, Failure Prediction and Damage Mechanisms in 2D Triaxial Braided Composites with Notch

    NASA Technical Reports Server (NTRS)

    Norman, Timothy L.; Anglin, Colin

    1995-01-01

    The unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2D) triaxial braided composites were examined. The effect of notch size and notch position were investigated. Damage initiation and propagation in notched and unnotched coupons were also examined. Theory developed to predict the normal stress distribution near an open hole and failure for tape laminated composites was evaluated for its applicability to 2D triaxial braided textile composite materials. Four different fiber architectures were considered; braid angle, yarn and braider size, percentage of longitudinal yarns and braider angle varied. Tape laminates equivalent to textile composites were also constructed for comparison. Unnotched tape equivalents were stronger than braided textiles but exhibited greater notch sensitivity. Notched textiles and tape equivalents have roughly the same strength at large notch sizes. Two common damage mechanisms were found: braider yarn cracking and near notch longitudinal yarn splitting. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and propagate in the direction of the braider yarns until failure. Damage initiation stress decreased with increasing braid angle. No significant differences in prediction of near notch strain between textile and tape equivalents could be detected for small braid angle, but the correlations were weak for textiles with large braid angle. Notch strength could not be predicted using existing anisotropic theory for braided textiles due to their insensitivity to notch.

  5. Non-invasive ventilation for weaning, avoiding reintubation after extubation and in the postoperative period: a meta-analysis.

    PubMed

    Glossop, A J; Shephard, N; Shepherd, N; Bryden, D C; Mills, G H

    2012-09-01

    Non-invasive ventilation (NIV) is a supportive therapy that improves mortality in acute respiratory failure (RF). It may also be used in patients recently extubated in intensive care units (ICUs), after operation, and to aid weaning from mechanical ventilation (MV) by reducing the morbidity and mortality associated with further MV. A meta-analysis of the available evidence was performed on the use of NIV in three areas: weaning, reduction in reintubation rates post-extubation on ICU, and reduction in RF after major surgery. Sixteen relevant randomized controlled trials were identified by three reviewers after a detailed search of identified medical databases. A meta-analysis of summary statistics relating to predetermined endpoints (ICU and hospital length of stay, ICU and hospital mortality, reintubation, pneumonia) was performed. NIV reduced the ICU length of stay when used for weaning (5.12 days) and post-surgery (0.44 days). NIV reduced reintubation rates post-surgery [odds ratio (OR) 0.24, 95% confidence interval (CI) 0.12-0.50] and the incidence of pneumonia in weaning (OR 0.12, 95% CI 0.05-0.31) and post-surgery (OR 0.27, 95% CI 0.09-0.77). There was insufficient evidence to suggest that NIV improves ICU survival, but an increased hospital survival in post-surgery (OR 4.54, [corrected] 95% CI 1.35-15.31) and a reduction after weaning (OR 0.55, 95% CI 0.31-0.98) [corrected] was seen. A meta analysis of NIV use in selected subgroups of recently extubated patients suggests that the judicious NIV use may reduce ICU and hospital length of stay, pneumonia, and reintubation rates and hospital survival.

  6. A Predictive Safety Management System Software Package Based on the Continuous Hazard Tracking and Failure Prediction Methodology

    NASA Technical Reports Server (NTRS)

    Quintana, Rolando

    2003-01-01

    The goal of this research was to integrate a previously validated and reliable safety model, called Continuous Hazard Tracking and Failure Prediction Methodology (CHTFPM), into a software application. This led to the development of a safety management information system (PSMIS). This means that the theory or principles of the CHTFPM were incorporated in a software package; hence, the PSMIS is referred to as CHTFPM management information system (CHTFPM MIS). The purpose of the PSMIS is to reduce the time and manpower required to perform predictive studies as well as to facilitate the handling of enormous quantities of information in this type of studies. The CHTFPM theory encompasses the philosophy of looking at the concept of safety engineering from a new perspective: from a proactive, than a reactive, viewpoint. That is, corrective measures are taken before a problem instead of after it happened. That is why the CHTFPM is a predictive safety because it foresees or anticipates accidents, system failures and unacceptable risks; therefore, corrective action can be taken in order to prevent all these unwanted issues. Consequently, safety and reliability of systems or processes can be further improved by taking proactive and timely corrective actions.

  7. Plasma Levels of sRAGE, Loss of Aeration and Weaning Failure in ICU Patients: A Prospective Observational Multicenter Study

    PubMed Central

    Jabaudon, Matthieu; Perbet, Sébastien; Pereira, Bruno; Soummer, Alexis; Roszyk, Laurence; Guérin, Renaud; Futier, Emmanuel; Lu, Qin; Bazin, Jean-Etienne; Sapin, Vincent; Rouby, Jean-Jacques; Constantin, Jean-Michel

    2013-01-01

    Rationale Postextubation distress after a successful spontaneous breathing trial (SBT) is associated with increased morbidity and mortality. Lung ultrasound determination of changes in lung aeration predicts weaning failure. It remains unknown whether this derecruitment is related to alveolar epithelial dysfunction or not. Objective To verify whether lung alveolar type I epithelial cell injury marker sRAGE (soluble form of the receptor for advanced glycation end-products) is predictive of postextubation distress and weaning failure or not, and to verify whether plasma sRAGE levels can be related to lung derecruitment during the process of weaning from mechanical ventilation or not. Interventions, Measurements 88 patients from 2 intensive care units were included in this observational prospective study. Plasma sRAGE levels were measured in duplicate by ELISA before, at the end of a 60-minute SBT, and 4 hours after extubation. To quantify lung aeration, a lung ultrasound score was calculated. Main Results 34% of extubated patients experienced postextubation distress. Patients with or without postextubation distress had comparable sRAGE levels before SBT, after SBT, and 4 hours after extubation. In patients with postextubation distress, sRAGE levels were not predictive of the need for mechanical ventilation. sRAGE levels were not associated with lung aeration as assessed by echography. Patients who succeeded SBT (86%) and those who failed (14%) had no differences in sRAGE levels, before (median 1111 vs 1021 pg/mL, p = 0,87) and at the end of SBT (1165 vs 1038 pg/mL, p = 0.74). Conclusions Plasma levels of sRAGE do not predict postextubation distress or SBT failure/success in patients weaning from mechanical ventilation. Lung aeration loss during a successful weaning trial predicts postextubation distress, but may not be evaluable by plasma levels of sRAGE, a marker of alveolar type I epithelial cell injury. Trial Registration ClinicalTrials.gov NCT01098773

  8. Is it beneficial to approximate pre-failure topography to predict landslide susceptibility with empirical models?

    NASA Astrophysics Data System (ADS)

    Steger, Stefan; Schmaltz, Elmar; Glade, Thomas

    2017-04-01

    Empirical landslide susceptibility maps spatially depict the areas where future slope failures are likely due to specific environmental conditions. The underlying statistical models are based on the assumption that future landsliding is likely to occur under similar circumstances (e.g. topographic conditions, lithology, land cover) as past slope failures. This principle is operationalized by applying a supervised classification approach (e.g. a regression model with a binary response: landslide presence/absence) that enables discrimination between conditions that favored past landslide occurrences and the circumstances typical for landslide absences. The derived empirical relation is then transferred to each spatial unit of an area. Literature reveals that the specific topographic conditions representative for landslide presences are frequently extracted from derivatives of digital terrain models at locations were past landslides were mapped. The underlying morphology-based landslide identification becomes possible due to the fact that the topography at a specific locality usually changes after landslide occurrence (e.g. hummocky surface, concave and steep scarp). In a strict sense, this implies that topographic predictors used within conventional statistical landslide susceptibility models relate to post-failure topographic conditions - and not to the required pre-failure situation. This study examines the assumption that models calibrated on the basis of post-failure topographies may not be appropriate to predict future landslide locations, because (i) post-failure and pre-failure topographic conditions may differ and (ii) areas were future landslides will occur do not yet exhibit such a distinct post-failure morphology. The study was conducted for an area located in the Walgau region (Vorarlberg, western Austria), where a detailed inventory consisting of shallow landslides was available. The methodology comprised multiple systematic comparisons of models

  9. Development of A Tabulated Thermo-Viscoplastic Material Model with Regularized Failure for Dynamic Ductile Failure Prediction of Structures under Impact Loading

    NASA Astrophysics Data System (ADS)

    Buyuk, Murat

    It is important to understand the dynamic failure behavior of structures subjected to impact loading in order to improve the survivability. Materials under impact are utterly affected by large deformations, high strain-rates, temperature softening and varying stress-states, which finally may lead to failure. It is shown that the impact characteristics are prone to change with several independent factors such as; impact speed, material thickness, and shape and orientation of the impacting object. Validated numerical simulations of impact tests reveal that the failure on ductile metals occur at certain locations of the failure locus that is constructed on a space as a function of all three stress invariants, which indicates that the failure depends profoundly on the state-of-stress. It is shown that existing material models are not always successful enough to cover the whole range of the failure locus and predict the failure. Therefore, it is a common practice to use different sets of material model parameters tuned or calibrated to cover a specific region of the failure loci in an ad hoc manner for practical reasons to match particular test results. Even in that case, specially tuned material properties are not capable of predicting these limited cases if differences in the mesh size and pattern need to be considered. In this dissertation a new, generic, thermo-elastic/viscoplastic material model with regularized failure is introduced. The new material model is implemented into a non-linear, explicit dynamics finite element code, LS-DYNA. A von Mises type isotropic, isochoric plasticity is utilized, where isotropic hardening, strain-rate hardening and temperature softening is considered. The model takes adiabatic heating and softening into account due to the plastic work. The constitutive relation is coupled with a new regularized accumulated failure law that is specifically developed to cover a large extent of the failure locus as a function of state

  10. Predicting Ductility and Failure Modes of TRIP Steels under Different Loading Conditions

    SciTech Connect

    Choi, Kyoo Sil; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

    2010-06-12

    We study the ultimate ductility and failure modes of a TRIP (TRansformation-Induced Plasticity) 800 steel under different loading conditions with an advanced micromechanics-based finite element analysis. The representative volume element (RVE) for the TRIP800 under examination is developed based on an actual microstructure obtained from scanning electron microscopy (SEM). The evolution of retained austenite during deformation process and the mechanical properties of the constituent phases of the TRIP800 steel are obtained from the synchrotron-based in-situ high-energy X-ray diffraction (HEXRD) experiments and a self-consistent (SC) model. The ductile failure of the TRIP800 under different loading conditions is predicted in the form of plastic strain localization without any prescribed failure criteria for the individual phases. Comparisons of the computational results with experimental measurements suggest that the microstructure-based finite element analysis can well capture the overall macroscopic behavior of the TRIP800 steel under different loading conditions. The methodology described in this study may be extended for studying the ultimate ductile failure mechanisms of TRIP steels as well as the effects of the various processing parameters on the macroscopic behaviors of TRIP steels.

  11. Prediction and prevention of failure: an early intervention to assist at-risk medical students.

    PubMed

    Winston, Kalman A; van der Vleuten, Cees P M; Scherpbier, Albert J J A

    2014-01-01

    Consistent identification and prevention of failure for at-risk medical students is challenging, failing courses is costly to all stakeholders, and there is need for further research into duration, timing and structure of interventions to help students in difficulty. To verify the value of a new exam two weeks into medical school as a predictor of failure, and explore the requirements for a preventative intervention. Students who failed the two-week exam were invited to a series of large-group workshops and small-group follow-up meetings. Participants' subsequent exam performance was compared with non-participants. About 71% of students who performed poorly in the new exam subsequently failed a course. Attendance at the workshops made no difference to short- or long-term pass rates. Attendance at more than three follow-up small group sessions significantly improved pass rates two semesters later, and was influenced by teacher experience. Close similarity between predictor task and target task is important for accurate prediction of failure. Consideration should be given to dose effect and class size in the prevention of failure of at-risk students, and we recommend a systemic approach to intervention/remediation programmes, involving a whole semester of mandatory, weekly small group meetings with experienced teachers.

  12. A Triaxial Failure Diagram to predict the forming limit of 3D sheet metal parts subjected to multiaxial stresses

    NASA Astrophysics Data System (ADS)

    Rastellini, F.; Socorro, G.; Forgas, A.; Onate, E.

    2016-08-01

    Accurate prediction of failure and forming limits is essential when modelling sheet metal forming processes. Since traditional Forming Limit Curves (FLCs) are not valid for materials subjected to triaxial loading, a new failure criterion is proposed in this paper based on the stress triaxility and the effective plastic strain accumulated during the history of material loading. Formability zones are identified inside the proposed Triaxial Failure Diagram (TFD). FLCs may be mapped into the TFD defining a new Triaxial Failure Curve, or it can be defined by triaxial failure experiments. Several TFD examples are validated and constrasted showing acceptable accuracy in the numerical prediction of forming failure/limit of 3D thick sheet parts.

  13. The Effect of Delamination on Damage Path and Failure Load Prediction for Notched Composite Laminates

    NASA Technical Reports Server (NTRS)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Chunchu, Prasad B.

    2007-01-01

    The influence of delamination on the progressing damage path and initial failure load in composite laminates is investigated. Results are presented from a numerical and an experimental study of center-notched tensile-loaded coupons. The numerical study includes two approaches. The first approach considers only intralaminar (fiber breakage and matrix cracking) damage modes in calculating the progression of the damage path. In the second approach, the model is extended to consider the effect of interlaminar (delamination) damage modes in addition to the intralaminar damage modes. The intralaminar damage is modeled using progressive damage analysis (PDA) methodology implemented with the VUMAT subroutine in the ABAQUS finite element code. The interlaminar damage mode has been simulated using cohesive elements in ABAQUS. In the experimental study, 2-3 specimens each of two different stacking sequences of center-notched laminates are tensile loaded. The numerical results from the two different modeling approaches are compared with each other and the experimentally observed results for both laminate types. The comparisons reveal that the second modeling approach, where the delamination damage mode is included together with the intralaminar damage modes, better simulates the experimentally observed damage modes and damage paths, which were characterized by splitting failures perpendicular to the notch tips in one or more layers. Additionally, the inclusion of the delamination mode resulted in a better prediction of the loads at which the failure took place, which were higher than those predicted by the first modeling approach which did not include delaminations.

  14. Multi-objective radiomics model for predicting distant failure in lung SBRT

    NASA Astrophysics Data System (ADS)

    Zhou, Zhiguo; Folkert, Michael; Iyengar, Puneeth; Westover, Kenneth; Zhang, Yuanyuan; Choy, Hak; Timmerman, Robert; Jiang, Steve; Wang, Jing

    2017-06-01

    Stereotactic body radiation therapy (SBRT) has demonstrated high local control rates in early stage non-small cell lung cancer patients who are not ideal surgical candidates. However, distant failure after SBRT is still common. For patients at high risk of early distant failure after SBRT treatment, additional systemic therapy may reduce the risk of distant relapse and improve overall survival. Therefore, a strategy that can correctly stratify patients at high risk of failure is needed. The field of radiomics holds great potential in predicting treatment outcomes by using high-throughput extraction of quantitative imaging features. The construction of predictive models in radiomics is typically based on a single objective such as overall accuracy or the area under the curve (AUC). However, because of imbalanced positive and negative events in the training datasets, a single objective may not be ideal to guide model construction. To overcome these limitations, we propose a multi-objective radiomics model that simultaneously considers sensitivity and specificity as objective functions. To design a more accurate and reliable model, an iterative multi-objective immune algorithm (IMIA) was proposed to optimize these objective functions. The multi-objective radiomics model is more sensitive than the single-objective model, while maintaining the same levels of specificity and AUC. The IMIA performs better than the traditional immune-inspired multi-objective algorithm.

  15. Distant failure prediction for early stage NSCLC by analyzing PET with sparse representation

    NASA Astrophysics Data System (ADS)

    Hao, Hongxia; Zhou, Zhiguo; Wang, Jing

    2017-03-01

    Positron emission tomography (PET) imaging has been widely explored for treatment outcome prediction. Radiomicsdriven methods provide a new insight to quantitatively explore underlying information from PET images. However, it is still a challenging problem to automatically extract clinically meaningful features for prognosis. In this work, we develop a PET-guided distant failure predictive model for early stage non-small cell lung cancer (NSCLC) patients after stereotactic ablative radiotherapy (SABR) by using sparse representation. The proposed method does not need precalculated features and can learn intrinsically distinctive features contributing to classification of patients with distant failure. The proposed framework includes two main parts: 1) intra-tumor heterogeneity description; and 2) dictionary pair learning based sparse representation. Tumor heterogeneity is initially captured through anisotropic kernel and represented as a set of concatenated vectors, which forms the sample gallery. Then, given a test tumor image, its identity (i.e., distant failure or not) is classified by applying the dictionary pair learning based sparse representation. We evaluate the proposed approach on 48 NSCLC patients treated by SABR at our institute. Experimental results show that the proposed approach can achieve an area under the characteristic curve (AUC) of 0.70 with a sensitivity of 69.87% and a specificity of 69.51% using a five-fold cross validation.

  16. Predicting in vivo failure of pseudoelastic NiTi devices under low cycle, high amplitude fatigue.

    PubMed

    Young, Jeremy M; Van Vliet, Krystyn J

    2005-01-15

    Due to the large reversible strains achievable through the stress-induced austenite-martensite phase transformation in NiTi alloys, NiTi has replaced stainless steel in the majority of large-strain biomedical applications such as root canal enlargement. However, the pseudoelasticity of NiTi is currently overshadowed by the short fatigue life of NiTi wires used in this low cycle (200-2000 rpm), high amplitude (epsilon(a) > 2.5%) application, resulting in in vivo fracture or premature retirement of otherwise reusable NiTi-based wire devices. In this study, the failure of pseudoelastic 55.8 wt % Ni-Ti wire is investigated experimentally, as a function of experimental parameters that include the clinically relevant regime. The effects of radius of curvature, angle of curvature, wire diameter, strain amplitude, cyclic frequency, volume under strain, and specific heat of the surrounding environmental fluid are considered systematically. These data indicate that the lifetime or cycles to failure N(f) of a rotating NiTi wire can be predicted via a modified Coffin-Manson relation that is a strong function of both strain amplitude and volume under strain, and a weaker function of frequency and fluid specific heat. The resulting quantitative relation can be used to predict useful device lifetime under clinically relevant conditions and thereby reduce incidences of in vivo failure.

  17. No site unseen: predicting the failure to control problematic Internet use among young adults.

    PubMed

    Yamada, Tetsuhiro; Moshier, Samantha J; Otto, Michael W

    2016-11-01

    Problematic Internet use has been associated with the neglect of valued activities such as work, exercise, social activities, and relationships. In the present study, we expanded the understanding of problematic Internet use by identifying an important predictor of the inability to curb Internet use despite the desire to do so. Specifically, in a college student sample reporting a mean of 27.8 h of recreational Internet use in the past week, we investigated the role of distress intolerance (DI)-an individual difference variable that refers to the inability of an individual to tolerate emotional discomfort and to engage in goal-directed behavior when distressed-to predict the failure to meet personal restrictions on Internet use. Consistent with hypotheses, DI emerged as a significant predictor of the failure to meet self-control goals in both bivariate and multivariate models, indicating that DI offers unique prediction of self-control failure with problematic Internet use. Given that DI is a modifiable trait, these results encourage consideration of DI-focused early intervention strategies.

  18. Methods for predicting peak discharge of floods caused by failure of natural and constructed earthen dams

    USGS Publications Warehouse

    Walder, J.S.; O'Connor, J. E.

    1997-01-01

    Floods from failures of natural and constructed dams constitute a widespread hazard to people and property. Expeditious means of assessing flood hazards are necessary, particularly in the case of natural dams, which may form suddenly and unexpectedly. We revise statistical relations (derived from data for past constructed and natural dam failures) between peak discharge (Q(p)) and water volume released (V(0)) or drop in lake level (d) but assert that such relations, even when cast into a dimensionless form, are of limited utility because they fail to portray the effect of breach-formation rate. We then analyze a simple, physically based model of dam-breach formation to show that the hydrograph at the breach depends primarily on a dimensionless parameter ?? = kV0/g1/2d7/2, where k is the mean erosion rate of the breach and g is acceleration due to gravity. The functional relationship between Q(p) and ?? takes asymptotically distinct forms depending on whether ?? << 1 (relatively slow breach formation or small lake volume) or ?? >> 1 (relatively fast breach formation or large lake volume). Theoretical predictions agree well with data from dam failures for which k, and thus ??, can be estimated. The theory thus provides a rapid means of predicting the plausible range of values of peak discharge at the breach in an earthen dam as long as the impounded water volume and the water depth at the dam face can be estimated.

  19. Heart rate turbulence predicts all-cause mortality and sudden death in congestive heart failure patients.

    PubMed

    Cygankiewicz, Iwona; Zareba, Wojciech; Vazquez, Rafael; Vallverdu, Montserrat; Gonzalez-Juanatey, Jose R; Valdes, Mariano; Almendral, Jesus; Cinca, Juan; Caminal, Pere; de Luna, Antoni Bayes

    2008-08-01

    Abnormal heart rate turbulence (HRT) has been documented as a strong predictor of total mortality and sudden death in postinfarction patients, but data in patients with congestive heart failure (CHF) are limited. The aim of this study was to evaluate the prognostic significance of HRT for predicting mortality in CHF patients in New York Heart Association (NYHA) class II-III. In 651 CHF patients with sinus rhythm enrolled into the MUSIC (Muerte Subita en Insuficiencia Cardiaca) study, the standard HRT parameters turbulence onset (TO) and slope (TS), as well as HRT categories, were assessed for predicting total mortality and sudden death. HRT was analyzable in 607 patients, mean age 63 years (434 male), 50% of ischemic etiology. During a median follow up of 44 months, 129 patients died, 52 from sudden death. Abnormal TS and HRT category 2 (HRT2) were independently associated with increased all-cause mortality (HR: 2.10, CI: 1.41 to 3.12, P <.001 and HR: 2.52, CI: 1.56 to 4.05, P <.001; respectively), sudden death (HR: 2.25, CI: 1.13 to 4.46, P = .021 for HRT2), and death due to heart failure progression (HR: 4.11, CI: 1.84 to 9.19, P <.001 for HRT2) after adjustment for clinical covariates in multivariate analysis. The prognostic value of TS for predicting total mortality was similar in various groups dichotomized by age, gender, NYHA class, left ventricular ejection fraction, and CHF etiology. TS was found to be predictive for total mortality only in patients with QRS > 120 ms. HRT is a potent risk predictor for both heart failure and arrhythmic death in patients with class II and III CHF.

  20. An endometrial gene expression signature accurately predicts recurrent implantation failure after IVF

    PubMed Central

    Koot, Yvonne E. M.; van Hooff, Sander R.; Boomsma, Carolien M.; van Leenen, Dik; Groot Koerkamp, Marian J. A.; Goddijn, Mariëtte; Eijkemans, Marinus J. C.; Fauser, Bart C. J. M.; Holstege, Frank C. P.; Macklon, Nick S.

    2016-01-01

    The primary limiting factor for effective IVF treatment is successful embryo implantation. Recurrent implantation failure (RIF) is a condition whereby couples fail to achieve pregnancy despite consecutive embryo transfers. Here we describe the collection of gene expression profiles from mid-luteal phase endometrial biopsies (n = 115) from women experiencing RIF and healthy controls. Using a signature discovery set (n = 81) we identify a signature containing 303 genes predictive of RIF. Independent validation in 34 samples shows that the gene signature predicts RIF with 100% positive predictive value (PPV). The strength of the RIF associated expression signature also stratifies RIF patients into distinct groups with different subsequent implantation success rates. Exploration of the expression changes suggests that RIF is primarily associated with reduced cellular proliferation. The gene signature will be of value in counselling and guiding further treatment of women who fail to conceive upon IVF and suggests new avenues for developing intervention. PMID:26797113

  1. Learning to drive: learners' self-reported cognitive failure level predicts driving instructor's observation rating of driving performance.

    PubMed

    Elfering, Achim; Ruppen, Veronique; Grebner, Simone

    2013-01-01

    Evidence increases that cognitive failure may be used to screen for drivers at risk. Until now, most studies have relied on driving learners. This exploratory pilot study examines self-report of cognitive failure in driving beginners and error during real driving as observed by driving instructors. Forty-two driving learners of 14 driving instructors filled out a work-related cognitive failure questionnaire. Driving instructors observed driving errors during the next driving lesson. In multiple linear regression analysis, driving errors were regressed on cognitive failure with the number of driving lessons as an estimator of driving experience controlled. Higher cognitive failure predicted more driving errors (p < .01) when age, gender and driving experience were controlled in analysis. Cognitive failure was significantly associated with observed driving errors. Systematic research on cognitive failure in driving beginners is recommended.

  2. NASA Langley developments in response calculations needed for failure and life prediction

    NASA Technical Reports Server (NTRS)

    Housner, Jerrold M.

    1993-01-01

    NASA Langley developments in response calculations needed for failure and life predictions are discussed. Topics covered include: structural failure analysis in concurrent engineering; accuracy of independent regional modeling demonstrated on classical example; functional interface method accurately joins incompatible finite element models; interface method for insertion of local detail modeling extended to curve pressurized fuselage window panel; interface concept for joining structural regions; motivation for coupled 2D-3D analysis; compression panel with discontinuous stiffener coupled 2D-3D model and axial surface strains at the middle of the hat stiffener; use of adaptive refinement with multiple methods; adaptive mesh refinement; and studies on quantity effect of bow-type initial imperfections on reliability of stiffened panels.

  3. NASA Langley developments in response calculations needed for failure and life prediction

    NASA Astrophysics Data System (ADS)

    Housner, Jerrold M.

    1993-10-01

    NASA Langley developments in response calculations needed for failure and life predictions are discussed. Topics covered include: structural failure analysis in concurrent engineering; accuracy of independent regional modeling demonstrated on classical example; functional interface method accurately joins incompatible finite element models; interface method for insertion of local detail modeling extended to curve pressurized fuselage window panel; interface concept for joining structural regions; motivation for coupled 2D-3D analysis; compression panel with discontinuous stiffener coupled 2D-3D model and axial surface strains at the middle of the hat stiffener; use of adaptive refinement with multiple methods; adaptive mesh refinement; and studies on quantity effect of bow-type initial imperfections on reliability of stiffened panels.

  4. Failure prediction in ceramic composites using acoustic emission and digital image correlation

    NASA Astrophysics Data System (ADS)

    Whitlow, Travis; Jones, Eric; Przybyla, Craig

    2016-02-01

    The objective of the work performed here was to develop a methodology for linking in-situ detection of localized matrix cracking to the final failure location in continuous fiber reinforced CMCs. First, the initiation and growth of matrix cracking are measured and triangulated via acoustic emission (AE) detection. High amplitude events at relatively low static loads can be associated with initiation of large matrix cracks. When there is a localization of high amplitude events, a measurable effect on the strain field can be observed. Full field surface strain measurements were obtained using digital image correlation (DIC). An analysis using the combination of the AE and DIC data was able to predict the final failure location.

  5. T-Wave Morphology Restitution Predicts Sudden Cardiac Death in Patients With Chronic Heart Failure.

    PubMed

    Ramírez, Julia; Orini, Michele; Mincholé, Ana; Monasterio, Violeta; Cygankiewicz, Iwona; Bayés de Luna, Antonio; Martínez, Juan Pablo; Pueyo, Esther; Laguna, Pablo

    2017-05-19

    Patients with chronic heart failure are at high risk of sudden cardiac death (SCD). Increased dispersion of repolarization restitution has been associated with SCD, and we hypothesize that this should be reflected in the morphology of the T-wave and its variations with heart rate. The aim of this study is to propose an electrocardiogram (ECG)-based index characterizing T-wave morphology restitution (TMR), and to assess its association with SCD risk in a population of chronic heart failure patients. Holter ECGs from 651 ambulatory patients with chronic heart failure from the MUSIC (MUerte Súbita en Insuficiencia Cardiaca) study were available for the analysis. TMR was quantified by measuring the morphological variation of the T-wave per RR increment using time-warping metrics, and its predictive power was compared to that of clinical variables such as the left ventricular ejection fraction and other ECG-derived indices, such as T-wave alternans and heart rate variability. TMR was significantly higher in SCD victims than in the rest of patients (median 0.046 versus 0.039, P<0.001). When TMR was dichotomized at TMR=0.040, the SCD rate was significantly higher in the TMR≥0.040 group (P<0.001). Cox analysis revealed that TMR≥0.040 was strongly associated with SCD, with a hazard ratio of 3.27 (P<0.001), independently of clinical and ECG-derived variables. No association was found between TMR and pump failure death. This study shows that TMR is specifically associated with SCD in a population of chronic heart failure patients, and it is a better predictor than clinical and ECG-derived variables. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  6. A single untimed plasma drug concentration measurement during low-level HIV viremia predicts virologic failure.

    PubMed

    Gonzalez-Serna, A; Swenson, L C; Watson, B; Zhang, W; Nohpal, A; Auyeung, K; Montaner, J S; Harrigan, P R

    2016-12-01

    Suboptimal untimed plasma drug levels (UDL) have been associated with lower rates of virologic suppression and the emergence of drug resistance. Our aim was to evaluate whether UDL among patients with low-level viremia (LLV) while receiving highly active antiretroviral therapy (HAART) can predict subsequent virologic failure (plasma viral load ≥1000 copies/mL) and emergence of resistance. The first documented LLV episode of 328 consenting patients was analysed in terms of drug levels, viral load and resistance, which were monitored while patients were on a consistent HAART regimen. UDL of protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs), were categorized as 'therapeutic' or 'subtherapeutic' based on predefined target trough concentrations. Drug resistance genotype was assessed using the Stanford algorithm. Time to virologic failure was evaluated by Kaplan-Meier analysis and Cox proportional hazards regression. We found 78 of 328 patients (24%) with subtherapeutic drug levels at time of first detectable LLV, while 19% harboured drug-resistant virus. Both subtherapeutic UDL and drug resistance independently increased the risk of subsequent virologic failure (p <0.001 and p 0.04, respectively). In a multivariable model, variables associated with LLV and virologic failure included subtherapeutic UDL, elevated plasma viral load, and drug resistance. Patients with subtherapeutic UDL accumulated further drug resistance faster during follow-up (p 0.03). Together, resistance and UDL variables can explain a higher proportion of virologic failure than either measure alone. Our results support further prospective evaluation of UDL in the management of low-level viremia. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  7. Risk Analysis of the Space Shuttle: Pre-Challenger Bayeisan Prediction of Failure

    SciTech Connect

    Dana L. Kelly

    2008-02-01

    Dalal et al performed a statistical analysis of field and nozzle O-ring data collected prior to the ill-fated launch of the Challenger in January 1986. The purpose of their analysis was to show how statistical analysis could be used to provide information to decisionmakers prior to the launch, information that could have been expected to lead to a decision to abort the launch due to the low temperatures (~30o F.) present at the launch pad on the morning of the scheduled launch. Dalal et al. performed a frequentist analysis of the O-ring data, and found that a logistic regression model provided a relatively good fit to the past data. In the second portion of their paper, Dalal et al. propagated parameter uncertainties through the fitted logistic regression model in order to estimate the probability of shuttle failure due to O-ring failure at the estimated launch temperature of ~30o F. Because their analysis was frequentist in nature, probability distributions representing epistemic uncertainty in the input parameters were not available, and the authors had to resort to an approximate approach based on bootstrap confidence intervals. In this paper, we will re-evaluate the analyses of Dalal et al. from a Bayesian perspective. Markov chain Monte Carlo (MCMC) sampling will be used to sample from the joint posterior distribution of the model parameters, and to sample from the posterior predictive distributions at the estimated launch temperature, a temperature that had not been observed in prior launches of the space shuttle. Uncertainties, which are represented by probability distributions in the Bayesian approach, are propagated through the model to obtain a probability distribution for O-ring failure, and subsequently for shuttle failure as a result of O-ring failure. No approximations are required in the Bayesian approach and the resulting distributions can be input to a decision analysis to obtain expected utility for the decision to launch.

  8. [Factors associated with atelectasis following extubation in very low weight premature newborns].

    PubMed

    Castilla-Castilla, Cristina María Del Carmen; Vidales-Roque, Lydia Beatriz; Pérez-Durán, Juana; Tena-Reyes, Daniel; Tapia-Rombo, Carlos Antonio

    2014-01-01

    Atelectasis is a decrease of lung volume caused by airway obstruction or pressure on the external part of the lung. It is common after surgery and extubation. The purpose of this investigation was to determine factors related with alectasis following extubation in preterm neonates with a weight under 1250 g who were referred to a neonatal intensive care unit. The study was conducted in neonates admitted to a neonatal intensive care unit requiring mechanically assisted ventilation. Preterm neonates born at 28 to 36 weeks' gestation and with 0 to 28 days' extrauterine life, with mechanically assisted ventilation for at least 24 hours, and that when undergoing planned extubation had a weight under 1250 g were included. Two comparative groups were formed: group A, with alectasis after extubation; group B, without alectasis after extubation. As factors associated with alectasis after extubation, reintubation in two or more occasions and cycling higher than 20 per minute, which were statistically relevant, were identified. In addition to previous general measures to prevent alectasis, extubation with ventilation not higher tan 20 cycles per minute should be programmed and reintubation should be avoided as much as possible.

  9. Post-extubation stridor in Respiratory Syncytial Virus bronchiolitis: Is there a role for prophylactic dexamethasone?

    PubMed Central

    Kappen, Teus H.; Calis, Job C.; van Woensel, Job; Raymakers-Janssen, Paulien A. M.; Bont, Louis J.; Hennus, Marije P.

    2017-01-01

    Aim The purpose of this study was to determine the incidence of reintubation due to upper airway obstruction in a homogeneous group of ventilated infants with Respiratory Syncytial Virus bronchiolitis. Our secondary objective was to determine whether prophylactic administration of dexamethasone prior to extubation was associated with decreased risk of reintubation. Methods This retrospective observational study in two Pediatric Intensive Care Units in 2 university hospitals in The Netherlands included two hundred patients younger than 13 months admitted with respiratory insufficiency caused by Respiratory Syncytial Virus bronchiolitis, requiring invasive mechanical ventilation. A logistic regression analysis with propensity score method was used to adjust for possible confounding. Results Reintubation due to post-extubation stridor occurred in 17 (8.5%) of 200 patients. After propensity score matching, administration of dexamethasone prior to extubation was associated with a significantly (p = 0.0011) decreased risk of reintubation due to post-extubation stridor compared to patients not receiving prophylactic dexamethasone (absolute risk reduction 13%, 95% CI 5.3–21%). Conclusion Reintubation due to post-extubation stridor is an important complication of ventilation for Respiratory Syncytial Virus bronchiolitis. Dexamethasone administered prior to extubation probably reduces the risk of post-extubation stridor necessitating reintubation in these infants. The results of this study support initiation of a placebo-controlled trial to confirm the beneficial effect of prophylactic dexamethasone. PMID:28207796

  10. Benefits of Immediate Extubation Following Free Tissue Transfer for Head and Neck Reconstruction.

    PubMed

    Tamplen, Matthew L; Ricceri, Santo; Hemmat, Shirin; Seth, Rahul; Ryan, William R; Knott, P Daniel

    2016-09-01

    Background Immediate postprocedure extubation (cessation of mechanical ventilation) after free tissue transfer for head and neck reconstruction may improve outcomes, reduce intensive care unit and hospital length of stay, and reduce overall cost compared with delayed extubation in the intensive care unit. Methods Medical records of 180 consecutive patients undergoing free tissue transfer for head and neck reconstruction were reviewed. Patients immediately extubated in the operating room (immediate group, N = 63) were compared with patients who were extubated in the intensive care unit (delayed group, N = 117) by univariate and multivariate analysis. Results Medical complication rates and intensive care unit length of stay were significantly higher in the delayed extubation group (55.5 vs. 12.7%, p < 0.001, and 4.4 vs. 2.9 days, p < 0.001, respectively). Although the rate of preoperative alcohol use was similar between the two groups, significantly fewer patients underwent treatment for alcohol withdrawal or agitation in the immediate extubation group (3.2 vs. 27.4%, p = 0.001). There were no significant differences in surgical complication rates. Conclusion Immediate postprocedure extubation is associated with shorter intensive care unit length of stay, reduced medical complications, and reduced incidence of treatment for agitation/alcohol withdrawal for patients undergoing free tissue transfer for head and neck reconstruction.

  11. Post-extubation stridor in Respiratory Syncytial Virus bronchiolitis: Is there a role for prophylactic dexamethasone?

    PubMed

    Veldhoen, Esther S; Smulders, Charlotte A; Kappen, Teus H; Calis, Job C; van Woensel, Job; Raymakers-Janssen, Paulien A M; Bont, Louis J; Hennus, Marije P

    2017-01-01

    The purpose of this study was to determine the incidence of reintubation due to upper airway obstruction in a homogeneous group of ventilated infants with Respiratory Syncytial Virus bronchiolitis. Our secondary objective was to determine whether prophylactic administration of dexamethasone prior to extubation was associated with decreased risk of reintubation. This retrospective observational study in two Pediatric Intensive Care Units in 2 university hospitals in The Netherlands included two hundred patients younger than 13 months admitted with respiratory insufficiency caused by Respiratory Syncytial Virus bronchiolitis, requiring invasive mechanical ventilation. A logistic regression analysis with propensity score method was used to adjust for possible confounding. Reintubation due to post-extubation stridor occurred in 17 (8.5%) of 200 patients. After propensity score matching, administration of dexamethasone prior to extubation was associated with a significantly (p = 0.0011) decreased risk of reintubation due to post-extubation stridor compared to patients not receiving prophylactic dexamethasone (absolute risk reduction 13%, 95% CI 5.3-21%). Reintubation due to post-extubation stridor is an important complication of ventilation for Respiratory Syncytial Virus bronchiolitis. Dexamethasone administered prior to extubation probably reduces the risk of post-extubation stridor necessitating reintubation in these infants. The results of this study support initiation of a placebo-controlled trial to confirm the beneficial effect of prophylactic dexamethasone.

  12. Logistic risk model predicting postoperative respiratory failure in patients undergoing valve surgery.

    PubMed

    Filsoufi, Farzan; Rahmanian, Parwis B; Castillo, Javier G; Chikwe, Joanna; Adams, David H

    2008-11-01

    Previous studies have been unable to identify independent valve-related risk factors for postoperative respiratory failure (RF) in patients undergoing valve surgery. This study was designed to determine the incidence and predictors of RF in these patients. We also aimed to create a model based on these risk factors that could serve as a tool for the prediction of this complication. We analyzed prospectively collected data of 2808 patients (mean age 63+/-15 years, 43% female) who underwent valve surgery from January 1998 to December 2006. Isolated valve surgery was performed in 2007 (72%) patients whereas 801 (28%) received concomitant coronary artery bypass grafting (CABG) procedures. The main outcome investigated was RF (ventilation >72 h). Other postoperative parameters included in the analysis were hospital mortality, morbidity, length of hospital stay, discharge and late survival. Respiratory failure occurred in 12.2% (n=342) of patients. The incidence of RF varied according to the procedures (single valve: 7.4-15.8%; multiple valves: 21.7-23.4%). The addition of CABG significantly increased the rate of RF (isolated valves: 10.8%, combined valve/CABG 15.7%, p<0.001). Multivariate analysis revealed preoperative renal failure, ejection fraction <30%, age >70 years, active endocarditis, emergent procedures, reoperation, diabetes, congestive heart failure, previous myocardial infarction, female gender, double aortic and mitral valve procedures, and cardiopulmonary bypass time >180 min as independent predictors of RF. Hospital mortality among patients with RF was 22.2% (n=76) versus 2.7% (n=66) in the control group (p<0.001). A logistic equation including the coefficients of the regression analysis was generated to calculate an individual patient's risk for the development of RF. Predictive accuracy of the model and validation was measured (ROC area under the curve: 0.751). Long-term survival of discharged patients with RF was significantly decreased compared to

  13. Attending Handoff Is Correlated with the Decision to Delay Extubation After Surgery.

    PubMed

    Anastasian, Zirka H; Kim, Minjae; Heyer, Eric J; Wang, Shuang; Berman, Mitchell F

    2016-03-01

    Factors including ASA physical status, blood loss, and case length have been described as correlating with the decision to delay tracheal extubation after specific surgical procedures. In this retrospective study, we investigated whether handoffs by anesthesia attendings were associated with delayed extubation after general anesthesia for a broad range of surgical procedures. We reviewed the records of 37,824 patients who underwent general anesthesia with an endotracheal tube for surgery (excluding tracheostomy surgery, cardiac surgeries, and liver and lung transplant surgeries) from 2008 to 2013 at Columbia University Medical Center. Our primary outcome was whether the patient was extubated at the end of the surgical case. We hypothesized that attending handoff was a factor that would independently affect the decision of the anesthesiologist to extubate at the end of the surgical case. In addition, we investigated whether the association between handoff and extubation was affected by the timing of the procedure (ending in the daytime versus evening hours) by including an interaction term in the analysis. We adjusted for other variables affecting the decision to delay extubation. Patients (5.4%, n = 2033) were not extubated in the operating room after the completion of their surgery. Cases with an attending handoff appeared to have a greater risk of delayed extubation with an adjusted risk ratio (aRR) of 1.14 (95% confidence interval [CI], 1.03-1.25). Further analysis demonstrated that the attending handoff had a significant effect in daytime cases (aRR, 1.62; 95% CI, 1.29-2.04) but not in evening cases (aRR, 1.07; 95% CI, 0.97-1.19). Attending handoff was an independent significant factor that increased the risk for the delay of extubation at the end of a surgical case.

  14. Predicting failure using conditioning on damage history: Demonstration on percolation and hierarchical fiber bundles

    SciTech Connect

    Andersen, J.V.; Sornette, D.

    2005-11-01

    We formulate the problem of probabilistic predictions of global failure in the simplest possible model based on site percolation and on one of the simplest models of time-dependent rupture, a hierarchical fiber bundle model. We show that conditioning the predictions on the knowledge of the current degree of damage (occupancy density p or number and size of cracks) and on some information on the largest cluster improves significantly the prediction accuracy, in particular by allowing one to identify those realizations which have anomalously low or large clusters (cracks). We quantify the prediction gains using two measures, the relative specific information gain (which is the variation of entropy obtained by adding new information) and the root mean square of the prediction errors over a large ensemble of realizations. The bulk of our simulations have been obtained with the two-dimensional site percolation model on a lattice of size LxL=20x20 and hold true for other lattice sizes. For the hierarchical fiber bundle model, conditioning the measures of damage on the information of the location and size of the largest crack extends significantly the critical region and the prediction skills. These examples illustrate how ongoing damage can be used as a revelation of both the realization-dependent preexisting heterogeneity and the damage scenario undertaken by each specific sample.

  15. Prediction of success and failure of behavior modification as treatment for dental anxiety.

    PubMed

    Eli, I; Baht, R; Blacher, S

    2004-08-01

    Behavior modification techniques are effective in the treatment of extreme dental anxiety, but their success is by no means absolute. In the present article, the Corah Dental Anxiety Scale (DAS), the self-report symptom inventory SCL-90R and a questionnaire accessing subjects' daydreaming styles (the Short Imaginal Process Inventory) were used to develop possible predictive measures for success and failure of behavior modification as a treatment for dental fear. The patients' level of distractibility and mind wandering, initial dental anxiety and somatization significantly predicted the success of therapy. The odds ratio indicated that the risk of therapy failure increased about 11 times with an increase of one scale of the Poor Attention Control Scale, about three times with an increase of one level of the mean DAS score, and 0.17 times with an increase of one level of somatization. The predictive value of the chosen scales was 80%. Thus, the use of these scales as part of an initial admittance process for patients who suffer from dental anxiety can enhance our ability to better recognize patients who are prone to fail behavior therapy as treatment for their problem, and enable their referral for other possible modes of treatment.

  16. A standardized model for predicting flap failure using indocyanine green dye

    NASA Astrophysics Data System (ADS)

    Zimmermann, Terence M.; Moore, Lindsay S.; Warram, Jason M.; Greene, Benjamin J.; Nakhmani, Arie; Korb, Melissa L.; Rosenthal, Eben L.

    2016-03-01

    Techniques that provide a non-invasive method for evaluation of intraoperative skin flap perfusion are currently available but underutilized. We hypothesize that intraoperative vascular imaging can be used to reliably assess skin flap perfusion and elucidate areas of future necrosis by means of a standardized critical perfusion threshold. Five animal groups (negative controls, n=4; positive controls, n=5; chemotherapy group, n=5; radiation group, n=5; chemoradiation group, n=5) underwent pre-flap treatments two weeks prior to undergoing random pattern dorsal fasciocutaneous flaps with a length to width ratio of 2:1 (3 x 1.5 cm). Flap perfusion was assessed via laser-assisted indocyanine green dye angiography and compared to standard clinical assessment for predictive accuracy of flap necrosis. For estimating flap-failure, clinical prediction achieved a sensitivity of 79.3% and a specificity of 90.5%. When average flap perfusion was more than three standard deviations below the average flap perfusion for the negative control group at the time of the flap procedure (144.3+/-17.05 absolute perfusion units), laser-assisted indocyanine green dye angiography achieved a sensitivity of 81.1% and a specificity of 97.3%. When absolute perfusion units were seven standard deviations below the average flap perfusion for the negative control group, specificity of necrosis prediction was 100%. Quantitative absolute perfusion units can improve specificity for intraoperative prediction of viable tissue. Using this strategy, a positive predictive threshold of flap failure can be standardized for clinical use.

  17. A model for predicting high-temperature fatigue failure of a W/Cu composite

    NASA Technical Reports Server (NTRS)

    Verrilli, M. J.; Kim, Y.-S.; Gabb, T. P.

    1991-01-01

    The material studied, a tungsten-fiber-reinforced, copper-matrix composite, is a candidate material for rocket nozzle liner applications. It was shown that at high temperatures, fatigue cracks initiate and propagate inside the copper matrix through a process of initiation, growth, and coalescence of grain boundary cavities. The ductile tungsten fibers neck and rupture locally after the surrounding matrix fails, and complete failure of the composite then ensues. A simple fatigue life prediction model is presented for the tungsten/copper composite system.

  18. Direct modeling parameter signature analysis and failure mode prediction of physical systems using hybrid computer optimization

    NASA Technical Reports Server (NTRS)

    Drake, R. L.; Duvoisin, P. F.; Asthana, A.; Mather, T. W.

    1971-01-01

    High speed automated identification and design of dynamic systems, both linear and nonlinear, are discussed. Special emphasis is placed on developing hardware and techniques which are applicable to practical problems. The basic modeling experiment and new results are described. Using the improvements developed successful identification of several systems, including a physical example as well as simulated systems, was obtained. The advantages of parameter signature analysis over signal signature analysis in go-no go testing of operational systems were demonstrated. The feasibility of using these ideas in failure mode prediction in operating systems was also investigated. An improved digital controlled nonlinear function generator was developed, de-bugged, and completely documented.

  19. Progressive failure methodologies for predicting residual strength and life of laminated composites

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Allen, David H.; Obrien, T. Kevin

    1991-01-01

    Two progressive failure methodologies currently under development by the Mechanics of Materials Branch at NASA Langley Research Center are discussed. The damage tolerance/fail safety methodology developed by O'Brien is an engineering approach to ensuring adequate durability and damage tolerance by treating only delamination onset and the subsequent delamination accumulation through the laminate thickness. The continuum damage model developed by Allen and Harris employs continuum damage laws to predict laminate strength and life. The philosophy, mechanics framework, and current implementation status of each methodology are presented.

  20. Numerical models for the prediction of failure for multilayer fusion Al-alloy sheets

    SciTech Connect

    Gorji, Maysam; Berisha, Bekim; Hora, Pavel; Timm, Jürgen

    2013-12-16

    Initiation and propagation of cracks in monolithic and multi-layer aluminum alloys, called “Fusion”, is investigated. 2D plane strain finite element simulations are performed to model deformation due to bending and to predict failure. For this purpose, fracture strains are measured based on microscopic pictures of Nakajima specimens. In addition to, micro-structure of materials is taken into account by introducing a random grain distribution over the sheet thickness as well as a random distribution of the measured yield curve. It is shown that the performed experiments and the introduced FE-Model are appropriate methods to highlight the advantages of the Fusion material, especially for bending processes.

  1. Predictive factors for pneumonia development and progression to respiratory failure in MERS-CoV infected patients.

    PubMed

    Ko, Jae-Hoon; Park, Ga Eun; Lee, Ji Yeon; Lee, Ji Yong; Cho, Sun Young; Ha, Young Eun; Kang, Cheol-In; Kang, Ji-Man; Kim, Yae-Jean; Huh, Hee Jae; Ki, Chang-Seok; Jeong, Byeong-Ho; Park, Jinkyeong; Chung, Chi Ryang; Chung, Doo Ryeon; Song, Jae-Hoon; Peck, Kyong Ran

    2016-11-01

    After the 2015 Middle East respiratory syndrome (MERS) outbreak in Korea, prediction of pneumonia development and progression to respiratory failure was emphasized in control of MERS outbreak. MERS-CoV infected patients who were managed in a tertiary care center during the 2015 Korean MERS outbreak were reviewed. To analyze predictive factors for pneumonia development and progression to respiratory failure, we evaluated clinical variables measured within three days from symptom onset. A total of 45 patients were included in the study: 13 patients (28.9%) did not develop pneumonia, 19 developed pneumonia without respiratory failure (42.2%), and 13 progressed to respiratory failures (28.9%). The identified predictive factors for pneumonia development included age ≥45 years, fever ≥37.5 °C, thrombocytopenia, lymphopenia, CRP ≥ 2 mg/dL, and a threshold cycle value of PCR less than 28.5. For respiratory failure, the indicators included male, hypertension, low albumin concentration, thrombocytopenia, lymphopenia, and CRP ≥ 4 mg/dL (all P < 0.05). With ≥ two predictive factors for pneumonia development, 100% of patients developed pneumonia. Patients lacking the predictive factors did not progress to respiratory failure. For successful control of MERS outbreak, MERS-CoV infected patients with ≥ two predictive factors should be intensively managed from the initial presentation. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  2. Predictions of High Strain Rate Failure Modes in Layered Aluminum Composites

    NASA Astrophysics Data System (ADS)

    Khanikar, Prasenjit; Zikry, M. A.

    2014-01-01

    A dislocation density-based crystalline plasticity formulation, specialized finite-element techniques, and rational crystallographic orientation relations were used to predict and characterize the failure modes associated with the high strain rate behavior of aluminum layered composites. Two alloy layers, a high strength alloy, aluminum 2195, and an aluminum alloy 2139, with high toughness, were modeled with representative microstructures that included precipitates, dispersed particles, and different grain boundary distributions. Different layer arrangements were investigated for high strain rate applications and the optimal arrangement was with the high toughness 2139 layer on the bottom, which provided extensive shear strain localization, and the high strength 2195 layer on the top for high strength resistance The layer thickness of the bottom high toughness layer also affected the bending behavior of the roll-bonded interface and the potential delamination of the layers. Shear strain localization, dynamic cracking, and delamination are the mutually competing failure mechanisms for the layered metallic composite, and control of these failure modes can be used to optimize behavior for high strain rate applications.

  3. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method

    PubMed Central

    Alani, Amir M.; Faramarzi, Asaad

    2015-01-01

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes. PMID:26068092

  4. Multiple Fatigue Failure Behaviors and Long-Life Prediction Approach of Carburized Cr-Ni Steel with Variable Stress Ratio

    PubMed Central

    Deng, Hailong; Li, Wei; Zhao, Hongqiao; Sakai, Tatsuo

    2017-01-01

    Axial loading tests with stress ratios R of −1, 0 and 0.3 were performed to examine the fatigue failure behavior of a carburized Cr-Ni steel in the long-life regime from 104 to 108 cycles. Results show that this steel represents continuously descending S-N characteristics with interior inclusion-induced failure under R = −1, whereas it shows duplex S-N characteristics with surface defect-induced failure and interior inclusion-induced failure under R = 0 and 0.3. The increasing tension eliminates the effect of compressive residual stress and promotes crack initiation from the surface or interior defects in the carburized layer. The FGA (fine granular area) formation greatly depends on the number of loading cycles, but can be inhibited by decreasing the compressive stress. Based on the evaluation of the stress intensity factor at the crack tip, the surface and interior failures in the short life regime can be characterized by the crack growth process, while the interior failure with the FGA in the long life regime can be characterized by the crack initiation process. In view of the good agreement between predicted and experimental results, the proposed approach can be well utilized to predict fatigue lives associated with interior inclusion-FGA-fisheye induced failure, interior inclusion-fisheye induced failure, and surface defect induced failure. PMID:28906454

  5. Failure Mode Classification for Life Prediction Modeling of Solid-State Lighting

    SciTech Connect

    Sakalaukus, Peter Joseph

    2015-08-01

    light power” of the SSL luminaire. The use of the Arrhenius equation necessitates two different temperature conditions, 25°C and 45°C are suggested by TM28, to determine the SSL lamp specific activation energy. One principal issue with TM28 is the lack of additional stresses or parameters needed to characterize non-temperature dependent failure mechanisms. Another principal issue with TM28 is the assumption that lumen maintenance or lumen depreciation gives an adequate comparison between SSL luminaires. Additionally, TM28 has no process for the determination of acceleration factors or lifetime estimations. Currently, a literature gap exists for established accelerated test methods for SSL devices to assess quality, reliability and durability before being introduced into the marketplace. Furthermore, there is a need for Physics-of-Failure based approaches to understand the processes and mechanisms that induce failure for the assessment of SSL reliability in order to develop generalized acceleration factors that better represent SSL product lifetime. This and the deficiencies in TM28 validate the need behind the development of acceleration techniques to quantify SSL reliability under a variety of environmental conditions. The ability to assess damage accrual and investigate reliability of SSL components and systems is essential to understanding the life time of the SSL device itself. The methodologies developed in this work increases the understanding of SSL devices iv through the investigation of component and device reliability under a variety of accelerated test conditions. The approaches for suitable lifetime predictions through the development of novel generalized acceleration factors, as well as a prognostics and health management framework, will greatly reduce the time and effort needed to produce SSL acceleration factors for the development of lifetime predictions.

  6. Predicting the time-temperature dependent axial failure of B/A1 composites

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.

    1980-01-01

    Experimental and theoretical studies were conducted in order to understand and predict the effects of time, temperature, and stress on the axial failure modes of boron fibers and B/A1 composites. Due to the anelastic nature of boron fiber deformation, it was possible to determine simple creep functions which can be employed to accurately describe creep and fracture stress of as-produced fibers. Analysis of damping and strength data for B/6061 A1 composites indicates that fiber creep effects of creep on fiber fracture are measurably reduced by the composite fabrication process. The creep function appropriate for fibers with B/Al composites was also determined. A fracture theory is presented for predicting the time-temperature dependence of the axial tensile strength for metal matrix composites in general and B/A1 composites in particular.

  7. Analyzing 30-Day Readmission Rate for Heart Failure Using Different Predictive Models.

    PubMed

    Mahajan, Satish; Burman, Prabir; Hogarth, Michael

    2016-01-01

    The Center for Medicare and Medical Services in the United States compares hospital's readmission performance to the facilities across the nation using a 30-day window from the hospital discharge. Heart Failure (HF) is one of the conditions included in the comparison, as it is the most frequent and the most expensive diagnosis for hospitalization. If risk stratification for readmission of HF patients could be carried out at the time of discharge from the index hospitalization, corresponding appropriate post-discharge interventions could be arranged. We, therefore, sought to compare two different risk prediction models using 48 clinical predictors from electronic health records data of 1037 HF patients from one hospital. We used logistic regression and random forest as methods of analyses and found that logistic regression with bagging approach produced better predictive results (C-Statistics: 0.65) when compared to random forest (C-Statistics: 0.61).

  8. Physical activity measured with implanted devices predicts patient outcome in chronic heart failure.

    PubMed

    Conraads, Viviane M; Spruit, Martijn A; Braunschweig, Frieder; Cowie, Martin R; Tavazzi, Luigi; Borggrefe, Martin; Hill, Michael R S; Jacobs, Sandra; Gerritse, Bart; van Veldhuisen, Dirk J

    2014-03-01

    Physical activity (PA) predicts cardiovascular mortality in the population at large. Less is known about its prognostic value in patients with chronic heart failure (HF). Data from 836 patients with implantable cardioverter defibrillator without or with cardiac resynchronization therapy enrolled in the Sensitivity of the InSync Sentry OptiVol feature for the prediction of Heart Failure (SENSE-HF)(1) study and the Diagnostic Outcome Trial in Heart Failure (DOT-HF) were pooled. The devices continuously measured and stored total daily active time (single-axis accelerometer). Early PA (average daily activity over the earliest 30-day study period) was studied as a predictor of time to death or HF-related hospital admission (primary end point). Data from 781 patients were analyzed (65±10 years; 85% men; left ventricular ejection fraction, 26±7%). Older age, shorter height, ischemic cause, peripheral artery disease, atrial fibrillation, diabetes mellitus, rales, peripheral edema, higher New York Heart Association class, lower diastolic blood pressure, and no angiotensin II receptor blocker/angiotensin-converting enzyme inhibitor use were associated with reduced early PA. The primary end point occurred in 135 patients (15±7 months of follow-up). In multivariable analysis including baseline variables, early PA predicted death or HF hospitalization, with a 4% reduction in risk for each 10 minutes per day additional activity (hazard ratio [HR], 0.96; confidence interval [CI], 0.94-0.98; P=0.0002 compared with a model with the same baseline variables but without PA). PA also predicted death (HR, 0.93; CI, 0.90-0.96; P<0.0001) and HF hospitalization (HR, 0.97; CI, 0.95-0.99; P=0.011). Early PA, averaged over a 30-day window early after defibrillator implantation or cardiac resynchronization therapy in patients with chronic HF, predicted death or HF hospitalization, as well as mortality and HF hospitalization separately, accounting for baseline HF severity. Clinical Trial

  9. A prediction model for sudden cardiac death in patients with heart failure and preserved ejection fraction.

    PubMed

    Adabag, Selcuk; Rector, Thomas S; Anand, Inder S; McMurray, John J; Zile, Michael; Komajda, Michel; McKelvie, Robert S; Massie, Barry; Carson, Peter E

    2014-11-01

    Sudden cardiac death (SCD) accounts for ∼ 25% of all deaths in heart failure with preserved ejection fraction (HFpEF). However, strategies to identify HFpEF patients at a higher risk of SCD have not been developed. We studied 4128 patients with HFpEF enrolled in the Irbesartan in Patients with Heart Failure and Preserved Ejection Fraction (I-PRESERVE) trial. All SCDs were adjudicated by a clinical endpoint committee. Cumulative incidences of SCD were estimated counting other deaths as competing risks. Cox regression analysis was used to generate a risk model for SCD. During a mean follow-up of 4.1 years, 231 (5.6%) patients died suddenly and 650 (15.7%) died non-suddenly. A multivariable model in 3480 patients including age, gender, history of diabetes and myocardial infarction, LBBB on ECG, and the natural logarithm of NT-proBNP identified a subgroup of 837 (24%) patients with ≥10% cumulative incidence of SCD over 5 years, accounting for other deaths as competing risk (Harrell's C index 0.75). The 5-year cumulative incidences of SCD in the higher and lower risk groups were 11% and 4%, respectively. In the higher risk group, 32% of deaths were SCD compared with 26% in the entire I-PRESERVE cohort. A multivariable prediction model identified patients with HFpEF who have a ≥10% risk of SCD over 5 years, similar to the risk of SCD in the Sudden Cardiac Death in Heart Failure (SCD-Heft) trial. This model may be useful for selecting patients with HFpEF for SCD prevention trials. © 2014 The Authors. European Journal of Heart Failure © 2014 European Society of Cardiology.

  10. Slope Failure Prediction and Early Warning Awareness Education for Reducing Landslides Casualty in Malaysia

    NASA Astrophysics Data System (ADS)

    Koay, S. P.; Tay, L. T.; Fukuoka, H.; Koyama, T.; Sakai, N.; Jamaludin, S. B.; Lateh, H.

    2015-12-01

    Northeast monsoon causes heavy rain in east coast of Peninsular Malaysia from November to March, every year. During this monsoon period, besides the happening of flood along east coast, landslides also causes millions of Malaysian Ringgit economical losses. Hence, it is essential to study the prediction of slope failure to prevent the casualty of landslides happening. In our study, we introduce prediction method of the accumulated rainfall affecting the stability of the slope. If the curve, in the graph, which is presented by rainfall intensity versus accumulated rainfall, crosses over the critical line, the condition of the slope is considered in high risk where the data are calculated and sent from rain gauge in the site via internet. If the possibility of slope failure is going high, the alert message will be sent out to the authorities for decision making on road block or setting the warning light at the road side. Besides road block and warning light, we propose to disseminate short message, to pre-registered mobile phone user, to notify the public for easing the traffic jam and avoiding unnecessary public panic. Prediction is not enough to prevent the casualty. Early warning awareness of the public is very important to reduce the casualty of landslides happening. IT technology does not only play a main role in disseminating information, early warning awareness education, by using IT technology, should be conducted, in schools, to give early warning awareness on natural hazard since childhood. Knowing the pass history on landslides occurrence will gain experience on the landslides happening. Landslides historical events with coordinate information are stored in database. The public can browse these historical events via internet. By referring to such historical landslides events, the public may know where did landslides happen before and the possibility of slope failure occurrence again is considered high. Simulation of rainfall induced slope failure mechanism

  11. Predicting distant failure in early stage NSCLC treated with SBRT using clinical parameters.

    PubMed

    Zhou, Zhiguo; Folkert, Michael; Cannon, Nathan; Iyengar, Puneeth; Westover, Kenneth; Zhang, Yuanyuan; Choy, Hak; Timmerman, Robert; Yan, Jingsheng; Xie, Xian-J; Jiang, Steve; Wang, Jing

    2016-06-01

    The aim of this study is to predict early distant failure in early stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy (SBRT) using clinical parameters by machine learning algorithms. The dataset used in this work includes 81 early stage NSCLC patients with at least 6months of follow-up who underwent SBRT between 2006 and 2012 at a single institution. The clinical parameters (n=18) for each patient include demographic parameters, tumor characteristics, treatment fraction schemes, and pretreatment medications. Three predictive models were constructed based on different machine learning algorithms: (1) artificial neural network (ANN), (2) logistic regression (LR) and (3) support vector machine (SVM). Furthermore, to select an optimal clinical parameter set for the model construction, three strategies were adopted: (1) clonal selection algorithm (CSA) based selection strategy; (2) sequential forward selection (SFS) method; and (3) statistical analysis (SA) based strategy. 5-cross-validation is used to validate the performance of each predictive model. The accuracy was assessed by area under the receiver operating characteristic (ROC) curve (AUC), sensitivity and specificity of the system was also evaluated. The AUCs for ANN, LR and SVM were 0.75, 0.73, and 0.80, respectively. The sensitivity values for ANN, LR and SVM were 71.2%, 72.9% and 83.1%, while the specificity values for ANN, LR and SVM were 59.1%, 63.6% and 63.6%, respectively. Meanwhile, the CSA based strategy outperformed SFS and SA in terms of AUC, sensitivity and specificity. Based on clinical parameters, the SVM with the CSA optimal parameter set selection strategy achieves better performance than other strategies for predicting distant failure in lung SBRT patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. Can the theory of critical distances predict the failure of shape memory alloys?

    PubMed

    Kasiri, Saeid; Kelly, Daniel J; Taylor, David

    2011-06-01

    Components made from shape memory alloys (SMAs) such as nitinol often fail from stress concentrations and defects such as notches and cracks. It is shown here for the first time that these failures can be predicted using the theory of critical distances (TCDs), a method which has previously been used to study fracture and fatigue in other materials. The TCD uses the stress at a certain distance ahead of the notch to predict the failure of the material due to the stress concentration. The critical distance is believed to be a material property which is related to the microstructure of the material. The TCD is simply applied to a linear model of the material without the need to model the complication of its non-linear behaviour. The non-linear behaviour of the material at fracture is represented in the critical stress. The effect of notches and short cracks on the fracture of SMA NiTi was studied by analysing experimental data from the literature. Using a finite element model with elastic material behaviour, it is shown that the TCD can predict the effect of crack length and notch geometry on the critical stress and stress intensity for fracture, with prediction errors of less than 5%. The value of the critical distance obtained for this material was L = 90 μm; this may be related to its grain size. The effects of short cracks on stress intensity were studied. It was shown that the same value of the critical distance (L = 90 μm) could estimate the experimental data for both notches and short cracks.

  13. Failure mechanisms and lifetime prediction methodology for polybutylene pipe in water distribution system

    NASA Astrophysics Data System (ADS)

    Niu, Xiqun

    Polybutylene (PB) is a semicrystalline thermoplastics. It has been widely used in potable water distribution piping system. However, field practice shows that failure occurs much earlier than the expected service lifetime. What are the causes and how to appropriately evaluate its lifetime motivate this study. In this thesis, three parts of work have been done. First is the understanding of PB, which includes material thermo and mechanical characterization, aging phenomena and notch sensitivity. The second part analyzes the applicability of the existing lifetime testing method for PB. It is shown that PB is an anomaly in terms of the temperature-lifetime relation because of the fracture mechanism transition across the testing temperature range. The third part is the development of the methodology of lifetime prediction for PB pipe. The fracture process of PB pipe consists of three stages, i.e., crack initiation, slow crack growth (SCG) and crack instability. The practical lifetime of PB pipe is primarily determined by the duration of the first two stages. The mechanism of crack initiation and the quantitative estimation of the time to crack initiation are studied by employing environment stress cracking technique. A fatigue slow crack growth testing method has been developed and applied in the study of SCG. By using Paris-Erdogan equation, a model is constructed to evaluate the time for SCG. As a result, the total lifetime is determined. Through this work, the failure mechanisms of PB pipe has been analyzed and the lifetime prediction methodology has been developed.

  14. Diagnostic prediction of renal failure from blood serum analysis by FTIR spectrometry and chemometrics.

    PubMed

    Khanmohammadi, Mohammdreza; Ghasemi, Keyvan; Garmarudi, Amir Bagheri; Ramin, Mehdi

    2015-02-05

    A new diagnostic approach based on Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectrometry and classification algorithm has been introduced which provides a rapid, reliable, and easy way to perform blood test for the diagnosis of renal failure. Blood serum samples from 35 renal failure patients and 40 healthy persons were analyzed by ATR-FTIR spectrometry. The resulting data was processed by Quadratic Discriminant Analysis (QDA) and QDA combined with simple filtered method. Spectroscopic studies were performed in 900-2000cm(-)(1) spectral region with 3.85cm(-1) data space. Results showed 93.33% and 100% of accuracy for QDA and filter-QDA models, respectively. In the first step, 30 samples were applied to construct the model. In order to modify the capability of QDA in prediction of test samples, filter-based feature selection methods were applied. It was found that the filtered spectra coupled with QDA could correctly predict the test samples in most of the cases.

  15. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas; Goyal, Vinay; Lundgren, Eric; Patel, Dhruv; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and facesheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  16. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas; Goyal, Vinay; Lundgren, Eric; Patel, Dhruv; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. Fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a strength reduction of 10 percent due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  17. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas A.; Goyal, Vinay K.; Lundgren, Eric C.; Patel, Dhruv N.; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth N.

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  18. Application of a neural network as a potential aid in predicting NTF pump failure

    NASA Technical Reports Server (NTRS)

    Rogers, James L.; Hill, Jeffrey S.; Lamarsh, William J., II; Bradley, David E.

    1993-01-01

    The National Transonic Facility has three centrifugal multi-stage pumps to supply liquid nitrogen to the wind tunnel. Pump reliability is critical to facility operation and test capability. A highly desirable goal is to be able to detect a pump rotating component problem as early as possible during normal operation and avoid serious damage to other pump components. If a problem is detected before serious damage occurs, the repair cost and downtime could be reduced significantly. A neural network-based tool was developed for monitoring pump performance and aiding in predicting pump failure. Once trained, neural networks can rapidly process many combinations of input values other than those used for training to approximate previously unknown output values. This neural network was applied to establish relationships among the critical frequencies and aid in predicting failures. Training pairs were developed from frequency scans from typical tunnel operations. After training, various combinations of critical pump frequencies were propagated through the neural network. The approximated output was used to create a contour plot depicting the relationships of the input frequencies to the output pump frequency.

  19. Diagnostic prediction of renal failure from blood serum analysis by FTIR spectrometry and chemometrics

    NASA Astrophysics Data System (ADS)

    Khanmohammadi, Mohammdreza; Ghasemi, Keyvan; Garmarudi, Amir Bagheri; Ramin, Mehdi

    2015-02-01

    A new diagnostic approach based on Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectrometry and classification algorithm has been introduced which provides a rapid, reliable, and easy way to perform blood test for the diagnosis of renal failure. Blood serum samples from 35 renal failure patients and 40 healthy persons were analyzed by ATR-FTIR spectrometry. The resulting data was processed by Quadratic Discriminant Analysis (QDA) and QDA combined with simple filtered method. Spectroscopic studies were performed in 900-2000 cm-1 spectral region with 3.85 cm-1 data space. Results showed 93.33% and 100% of accuracy for QDA and filter-QDA models, respectively. In the first step, 30 samples were applied to construct the model. In order to modify the capability of QDA in prediction of test samples, filter-based feature selection methods were applied. It was found that the filtered spectra coupled with QDA could correctly predict the test samples in most of the cases.

  20. Prognostic Factors Predicting Poor Outcome in Living-Donor Liver Transplantation for Fulminant Hepatic Failure.

    PubMed

    Kim, T-S; Kim, J M; Kwon, C H D; Kim, S J; Joh, J-W; Lee, S-K

    2017-06-01

    Living-donor liver transplantation (LDLT) has been accepted as feasible treatment for fulminant hepatic failure (FHF), although it has generated several debatable issues. In this study, we investigated the prognostic factors predicting fatal outcome after LDLT for FHF. From April 1999 to April 2011, 60 patients underwent LT for acute liver failure, including 42 patients for FHF at Samsung Medical Center, Seoul, Korea. Among 42 patients, 30 patients underwent LDLT for FHF, and the database of these patients was analyzed retrospectively to investigate the prognostic factors after LDLT for FHF. Among 30 patients, 7 patients (23%) died during the in-hospital period within 6 months, and 23 patients (77%) survived until recently. In univariate analyses, donor age (>35 years), graft volume (GV)/standard liver volume (SLV) (<50%), cold ischemic time (>120 minutes), hepatic encephalopathy (grade IV), hepato-renal syndrome (HRS), and history of ventilator care were associated with fatal outcome after LDLT for FHF. In multivariate analyses, HRS, GV/SLV (<50%), and donor age (>35 years) were significantly associated with fatal outcome. Although the statistical significance was not shown in this analysis (P = .059), hepatic encephalopathy grade IV also appears to be a risk factor predicting fatal outcome. The survival of patients with FHF undergoing LDLT was comparable to that in published data. In this study, HRS, GV/SLV <50%, and donor age >35 years are the independent poor prognostic factors. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Using different calculations of pharmacy refill adherence to predict virological failure among HIV-infected patients.

    PubMed

    de Boer, I Marion; Prins, Jan M; Sprangers, Mirjam A G; Nieuwkerk, Pythia T

    2010-12-15

    Refill data are increasingly used to assess adherence in HIV-infected patients on combination antiretroviral therapy. However, it is not clear how feasible this method is when multiple pharmacies are involved. Also, the effects of inclusion of leftover medication from previous refills and prescribed treatment time on adherence calculations are unknown. We addressed these questions in the present study. Adult HIV-1-infected patients were recruited at the outpatient clinic of the Academic Medical Centre in Amsterdam and asked for their pharmacies' names. Refill data were obtained from pharmacies. Percentages of patients misclassified as nonadherent when disregarding leftover medication and prescribed treatment interruptions were calculated. Finally, we investigated whether an average adherence calculation of all drugs or a calculation based on one drug in the regimen best predicted virological failure (plasma HIV-1 RNA >40 copies/mL). Two hundred one patients were included. Collecting data from multiple pharmacies (132) was found to be feasible. Forty-three percent of patients were misclassified as nonadherent when disregarding leftover medication and 2 percent when disregarding prescribed treatment time. There was no difference in predicting virological failure by different calculations of adherence. These findings suggest that studies using pharmacy refill data should include leftover medication.

  2. Post-Exercise Heart Rate Recovery Independently Predicts Mortality Risk in Patients with Chronic Heart Failure

    PubMed Central

    Tang, Yi-Da; Dewland, Thomas A.; Wencker, Detlef; Katz, Stuart D.

    2009-01-01

    Background Post-exercise heart rate recovery (HRR) is an index of parasympathetic function associated with clinical outcomes in populations with and without documented coronary heart disease. Decreased parasympathetic activity is thought to be associated with disease progression in chronic heart failure (HF), but an independent association between post-exercise HRR and clinical outcomes among such patients has not been established. Methods and Results We measured HRR (calculated as the difference between heart rate at peak exercise and after 1 minute of recovery) in 202 HF subjects and recorded 17 mortality and 15 urgent transplantation outcome events over 624 days of follow-up. Reduced post-exercise HRR was independently associated with increased event risk after adjusting for other exercise-derived variables (peak oxygen uptake and VE/VCO2 slope), for the Heart Failure Survival Score (adjusted HR 1.09 for one beat/min reduction, 95% CI 1.05-1.13, p<0.0001) and the Seattle Heart Failure Model score (adjusted HR 1.08 for one beat/min reduction, 95% CI 1.05-1.12, p<0.0001). Subjects in the lowest risk tertile based on post-exercise HRR (≥30 beats/min) had low risk of events irrespective of the risk predicted by the survival scores. In a subgroup of 15 subjects, reduced post-exercise HRR was associated with increased serum markers of inflammation (interleukin-6 r=0.58, p=0.024, high sensitivity C-reactive protein r=0.66, p=0.007). Conclusions Post-exercise HRR predicts mortality risk in patients with HF and provides prognostic information independent of previously described survival models. Pathophysiologic links between autonomic function and inflammation may be mediators of this association. PMID:19944361

  3. Post-exercise heart rate recovery independently predicts mortality risk in patients with chronic heart failure.

    PubMed

    Tang, Yi-Da; Dewland, Thomas A; Wencker, Detlef; Katz, Stuart D

    2009-12-01

    Post-exercise heart rate recovery (HRR) is an index of parasympathetic function associated with clinical outcomes in populations with and without documented coronary heart disease. Decreased parasympathetic activity is thought to be associated with disease progression in chronic heart failure (HF), but an independent association between post-exercise HRR and clinical outcomes among such patients has not been established. We measured HRR (calculated as the difference between heart rate at peak exercise and after 1 minute of recovery) in 202 HF subjects and recorded 17 mortality and 15 urgent transplantation outcome events over 624 days of follow-up. Reduced post-exercise HRR was independently associated with increased event risk after adjusting for other exercise-derived variables (peak oxygen uptake and change in minute ventilation per change in carbon dioxide production slope), for the Heart Failure Survival Score (adjusted HR 1.09 for 1 beat/min reduction, 95% CI 1.05-1.13, P < .0001), and the Seattle Heart Failure Model score (adjusted HR 1.08 for one beat/min reduction, 95% CI 1.05-1.12, P < .0001). Subjects in the lowest risk tertile based on post-exercise HRR (>or=30 beats/min) had low risk of events irrespective of the risk predicted by the survival scores. In a subgroup of 15 subjects, reduced post-exercise HRR was associated with increased serum markers of inflammation (interleukin-6, r = 0.58, P = .024; high-sensitivity C-reactive protein, r = 0.66, P = .007). Post-exercise HRR predicts mortality risk in patients with HF and provides prognostic information independent of previously described survival models. Pathophysiologic links between autonomic function and inflammation may be mediators of this association.

  4. Methods for applying statistical penalties when predicting factors of safety using the Tsai-Wu failure criterion

    NASA Astrophysics Data System (ADS)

    Richardson, D. E.; Regl, R. R.; Iverson, M. P.; Phipps, B. E.

    1993-06-01

    Engineers are often required to estimate safety factors for structures using statistically based allowable stresses. Several approaches for making such estimations are possible. Commonly, the Tsai-Wu failure criterion is used for composite materials. If the quadratic failure criterion proposed by S.W. Tsai and E.M. Wu is used with statistically penalized allowable stress levels, unrealistic results are possible unless the penalties are assessed carefully. Some approaches used in calculating safety factors can predict that the statistically determined allowable stress levels are greater than mean failure levels. Other methods predict that, under severe conditions, the penalized failure surface does not circumscribe the origin (i.e., the unloaded state would not be allowed). It is therefore important that designers and analysts take care when choosing an approach for predicting safety factors using statistically penalized data.

  5. Rapid and Highly Accurate Prediction of Poor Loop Diuretic Natriuretic Response in Patients With Heart Failure

    PubMed Central

    Testani, Jeffrey M.; Hanberg, Jennifer S.; Cheng, Susan; Rao, Veena; Onyebeke, Chukwuma; Laur, Olga; Kula, Alexander; Chen, Michael; Wilson, F. Perry; Darlington, Andrew; Bellumkonda, Lavanya; Jacoby, Daniel; Tang, W. H. Wilson; Parikh, Chirag R.

    2015-01-01

    Background Removal of excess sodium and fluid is a primary therapeutic objective in acute decompensated heart failure (ADHF) and commonly monitored with fluid balance and weight loss. However, these parameters are frequently inaccurate or not collected and require a delay of several hours after diuretic administration before they are available. Accessible tools for rapid and accurate prediction of diuretic response are needed. Methods and Results Based on well-established renal physiologic principles an equation was derived to predict net sodium output using a spot urine sample obtained one or two hours following loop diuretic administration. This equation was then prospectively validated in 50 ADHF patients using meticulously obtained timed 6-hour urine collections to quantitate loop diuretic induced cumulative sodium output. Poor natriuretic response was defined as a cumulative sodium output of <50 mmol, a threshold that would result in a positive sodium balance with twice-daily diuretic dosing. Following a median dose of 3 mg (2–4 mg) of intravenous bumetanide, 40% of the population had a poor natriuretic response. The correlation between measured and predicted sodium output was excellent (r=0.91, p<0.0001). Poor natriuretic response could be accurately predicted with the sodium prediction equation (AUC=0.95, 95% CI 0.89–1.0, p<0.0001). Clinically recorded net fluid output had a weaker correlation (r=0.66, p<0.001) and lesser ability to predict poor natriuretic response (AUC=0.76, 95% CI 0.63–0.89, p=0.002). Conclusions In patients being treated for ADHF, poor natriuretic response can be predicted soon after diuretic administration with excellent accuracy using a spot urine sample. PMID:26721915

  6. Increasing body mass index predicts increasing difficulty, failure rate, and time to discovery of failure of epidural anesthesia in laboring patients.

    PubMed

    Kula, Ayse O; Riess, Matthias L; Ellinas, Elizabeth H

    2017-02-01

    Obese parturients both greatly benefit from neuraxial techniques, and may represent a technical challenge to obstetric anesthesiologists. Several studies address the topic of obesity and neuraxial analgesia in general, but few offer well described definitions or rates of "difficulty" and "failure" of labor epidural analgesia. Providing those definitions, we hypothesized that increasing body mass index (BMI) is associated with negative outcomes in both categories and increased time needed for epidural placement. Single center retrospective chart review. Labor and Delivery Unit of an inner city academic teaching hospital. 2485 parturients, ASA status 2 to 4, receiving labor epidural analgesia for anticipated vaginal delivery. None. We reviewed quality assurance and anesthesia records over a 12-month period. "Failure" was defined as either inadequate analgesia or a positive test dose, requiring replacement, and/or when the anesthesia record stated they failed. "Difficulty" was defined as six or more needle redirections or a note indicating difficulty in the anesthesia record. Overall epidural failure and difficulty rates were 4.3% and 3.0%, respectively. Patients with a BMI of 30kg/m(2) or higher had a higher chance of both failure and difficulty with two and almost three fold increases, respectively. Regression analysis indicated that failure was best predicted by BMI and less provider training while difficulty was best predicted by BMI. Additionally, increased BMI was associated with increased time of discovery of epidural catheter failure. Obesity is associated with increasing technical difficulty and failure of neuraxial analgesia for labor. Practitioners should consider allotting extra time for obese parturients in order to manage potential problems. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Poor self-rated health predicts mortality in patients with stable chronic heart failure.

    PubMed

    Inkrot, Simone; Lainscak, Mitja; Edelmann, Frank; Loncar, Goran; Stankovic, Ivan; Celic, Vera; Apostolovic, Svetlana; Tahirovic, Elvis; Trippel, Tobias; Herrmann-Lingen, Christoph; Gelbrich, Götz; Düngen, Hans-Dirk

    2016-12-01

    In heart failure, a holistic approach incorporating the patient's perspective is vital for prognosis and treatment. Self-rated health has strong associations with adverse events and short-term mortality risk, but long-term data are limited. We investigated the predictive value of two consecutive self-rated health assessments with regard to long-term mortality in a large, well characterised sample of elderly patients with stable chronic heart failure. We measured self-rated health by asking 'In general, would you say your health is: 1, excellent; 2, very good; 3, good; 4, fair; 5, poor?' twice: at baseline and the end of a 12-week beta-blocker up-titration period in the CIBIS-ELD trial. Mortality was assessed in an observational follow-up after 2-4 years. A total of 720 patients (mean left ventricular ejection fraction 45±12%, mean age 73±5 years, 36% women) rated their health at both time points. During long-term follow-up, 144 patients died (all-cause mortality 20%). Fair/poor self-rated health in at least one of the two reports was associated with increased mortality (hazard ratio 1.42 per level; 95% confidence interval 1.16-1.75; P<0.001). It remained independently significant in multiple Cox regression analysis, adjusted for N-terminal pro B-type natriuretic peptide (NTproBNP), heart rate and other risk prediction covariates. Self-rated health by one level worse was as predictive for mortality as a 1.9-fold increase in NTproBNP. Poor self-rated health predicts mortality in our long-term follow-up of patients with stable chronic heart failure, even after adjustment for established risk predictors. We encourage clinicians to capture patient-reported self-rated health routinely as an easy to assess, clinically meaningful measure and pay extra attention when self-rated health is poor. © The European Society of Cardiology 2015.

  8. Post extubation negative pressure pulmonary edema due to posterior mediastinal cyst in an infant.

    PubMed

    Dubey, Prakash Kumar

    2014-01-01

    A 3-month-old male child underwent uneventful inguinal herniotomy under general anesthesia. After extubation, airway obstruction followed by pulmonary edema appeared for which the baby was reintubated and ventilated. The baby made a complete recovery and extubated after about 2 h. A post-operative computed tomography scan revealed a posterior mediastinal cystic mass abutting the tracheal bifurcation. Presumably, extrinsic compression by the mass on the tracheal bifurcation led to the development of negative pressure pulmonary edema.

  9. Does extubation result in haemodynamic instability in patients following coronary artery bypass grafts?

    PubMed

    Walthall, H; Ray, S; Robson, D

    2001-10-01

    Coronary heart disease and its management continue to be at the centre of Government health policy. The present political climate demands clinical effectiveness and best practice should be established, while maintaining the philosophy of cost-effectiveness and resource management. These directives have led practitioners to question the care of patients following coronary artery bypass surgery, in particular the role of mechanical ventilation and the subsequent act of extubation. A retrospective study of 89 patients who had coronary artery bypass grafts (emergency and elective) was undertaken, to establish if extubation had a significant effect on the haemodynamic status of patients with variable degrees of left ventricular function (19% with poor left ventricular function). The study found that extubation was achieved within a mean time of 4.97 hours following return from surgery. Extubation resulted in a significant increase in heart rate (P = 0.001), as well as a respiratory acidosis (pCO2: P = 0.000; pH: P = 0.000). However, the stability of the patient was not compromised, with neither mean arterial blood pressure (P = 0.825) nor oxygenation levels (P = 0.267) being significantly altered by extubation. On multivariate analysis, the act of extubation had no significant effect on any of the dependent variables. These results suggest that it is not extubation alone that has an impact on the haemodynamic stability of patients following coronary artery bypass grafts, but that this is indeed multifactorial. Therefore extubation is 'safe' practice for patients with varying degrees of left ventricular function following coronary artery bypass grafts. Limitations of the study are acknowledged.

  10. Attenuation of Cardiovascular Responses and Upper Airway Events to Tracheal Extubation by Low Dose Propofol

    PubMed Central

    Moein Vaziri, Mohammad Taghy; Jouybar, Reza; Moein Vaziri, Nader; Moein Vaziri, Najmeh; Panah, Ashkan

    2013-01-01

    Background Hemodynamic changes and respiratory tract complications are often followed by tracheal extubation. These events may be dangerous in neurosurgical patients and those with cardiovascular disease or at an old age. Objectives The aim of this study is to investigate the attenuation of cardiovascular responses and upper airway events resulting from tracheal extubation by low dose propofol. Materials and Methods 80 patients with ASA physical status I, undergoing an elective surgery in a double blind manner received 0.5mg/kg propofol or normal saline 2 minutes before extubation. Heart rate and blood pressure and quality of tracheal extubation were recorded. Results Heart rate and blood pressure in patients receiving propofol were less than the control group (P < 0.05) at the time of injection of propofol, but there were no differences between the two groups at the time of extubation. Conclusions We concluded that propofol can reduce SBP, DBP, MAP, HR & cough production at the time of injection but there were no significant changes in these parameters after extubation. PMID:24083001

  11. CrachFEM - A Comprehensive Approach For The Prediction Of Sheet Metal Failure

    SciTech Connect

    Dell, Harry; Gese, Helmut; Oberhofer, Gernot

    2007-05-17

    A correct prediction of a possible sheet metal failure is essential to sheet metal forming simulations. The use of the conventional forming limit curve (FLC) is the standard approach on industrial level for this problem. The FLC concept is limited to the case of linear strain paths, however. The initial FLC is no longer valid in the case of nonlinear strain paths. The algorithm Crach allows for a transient prediction of the forming limit for localized necking in the case of arbitrary strain paths. For high strength steels and aluminium sheets there is also a risk of fracture without prior localized necking. This paper presents a fracture model that accounts for ductile fracture (caused by void nucleation, void growth and void coalescence) and shear fracture (caused by shear band localization). For both types of fracture, stress state parameters are introduced which can be applied for the plane stress state and for the general 3D stress state. The fracture limits are defined by the equivalent plastic strain at fracture as a function of the stress state parameter based on different experiments with nearly constant stress state parameter. These fracture limit curves are a basis for an integral damage accumulation in the sheet metal forming simulation for arbitrary nonlinear strain paths. The model Crach for the prediction of localized necking and the two fracture models for ductile and shear fracture are combined in the comprehensive failure model CrachFEM. CrachFEM can be linked via a user material model MF GenYld to different explicit FEM codes.

  12. Postoperative Prostate-Specific Antigen Velocity Independently Predicts for Failure of Salvage Radiotherapy After Prostatectomy

    SciTech Connect

    King, Christopher R. Presti, Joseph C.; Brooks, James D.; Gill, Harcharan; Spiotto, Michael T.

    2008-04-01

    Purpose: Identification of patients most likely to benefit from salvage radiotherapy (RT) using postoperative (postop) prostate-specific antigen (PSA) kinetics. Methods and Materials: From 1984 to 2004, 81 patients who fit the following criteria formed the study population: undetectable PSA after radical prostatectomy (RP); pathologically negative nodes; biochemical relapse defined as a persistently detectable PSA; salvage RT; and two or more postop PSAs available before salvage RT. Salvage RT included the whole pelvic nodes in 55 patients and 4 months of total androgen suppression in 56 patients. The median follow-up was >5 years. All relapses were defined as a persistently detectable PSA. Kaplan-Meier and Cox proportional hazards multivariable analysis were performed for all clinical, pathological, and treatment factors predicting for biochemical relapse-free survival (bRFS). Results: There were 37 biochemical relapses observed after salvage RT. The 5-year bRFS after salvage RT for patients with postop prostate-specific antigen velocity {<=}1 vs. >1 ng/ml/yr was 59% vs. 29%, p = 0.002. In multivariate analysis, only postop PSAV (p = 0.0036), pre-RT PSA level {<=}1 (p = 0.037) and interval-to-relapse >10 months (p = 0.012) remained significant, whereas pelvic RT, hormone therapy, and RT dose showed a trend (p = {approx}0.06). PSAV, but not prostate-specific antigen doubling time, predicted successful salvage RT, suggesting an association of zero-order kinetics with locally recurrent disease. Conclusions: Postoperative PSA velocity independently predicts for the failure of salvage RT and can be considered in addition to high-risk features when selecting patients in need of systemic therapy following biochemical failure after RP. For well-selected patients, salvage RT can achieve high cure rates.

  13. CrachFEM — A Comprehensive Approach For The Prediction Of Sheet Metal Failure

    NASA Astrophysics Data System (ADS)

    Dell, Harry; Gese, Helmut; Oberhofer, Gernot

    2007-05-01

    A correct prediction of a possible sheet metal failure is essential to sheet metal forming simulations. The use of the conventional forming limit curve (FLC) is the standard approach on industrial level for this problem. The FLC concept is limited to the case of linear strain paths, however. The initial FLC is no longer valid in the case of nonlinear strain paths. The algorithm Crach allows for a transient prediction of the forming limit for localized necking in the case of arbitrary strain paths. For high strength steels and aluminium sheets there is also a risk of fracture without prior localized necking. This paper presents a fracture model that accounts for ductile fracture (caused by void nucleation, void growth and void coalescence) and shear fracture (caused by shear band localization). For both types of fracture, stress state parameters are introduced which can be applied for the plane stress state and for the general 3D stress state. The fracture limits are defined by the equivalent plastic strain at fracture as a function of the stress state parameter based on different experiments with nearly constant stress state parameter. These fracture limit curves are a basis for an integral damage accumulation in the sheet metal forming simulation for arbitrary nonlinear strain paths. The model Crach for the prediction of localized necking and the two fracture models for ductile and shear fracture are combined in the comprehensive failure model CrachFEM. CrachFEM can be linked via a user material model MF GenYld to different explicit FEM codes.

  14. Baseline Hemodynamics and Response to Contrast Media During Diagnostic Cardiac Catheterization Predict Adverse Events in Heart Failure Patients.

    PubMed

    Denardo, Scott J; Vock, David M; Schmalfuss, Carsten M; Young, Gregory D; Tcheng, James E; O'Connor, Christopher M

    2016-07-01

    Contrast media administered during cardiac catheterization can affect hemodynamic variables. However, little is documented about the effects of contrast on hemodynamics in heart failure patients or the prognostic value of baseline and changes in hemodynamics for predicting subsequent adverse events. In this prospective study of 150 heart failure patients, we measured hemodynamics at baseline and after administration of iodixanol or iopamidol contrast. One-year Kaplan-Meier estimates of adverse event-free survival (death, heart failure hospitalization, and rehospitalization) were generated, grouping patients by baseline measures of pulmonary capillary wedge pressure (PCWP) and cardiac index (CI), and by changes in those measures after contrast administration. We used Cox proportional hazards modeling to assess sequentially adding baseline PCWP and change in CI to 5 validated risk models (Seattle Heart Failure Score, ESCAPE [Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness], CHARM [Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity], CORONA [Controlled Rosuvastatin Multinational Trial in Heart Failure], and MAGGIC [Meta-Analysis Global Group in Chronic Heart Failure]). Median contrast volume was 109 mL. Both contrast media caused similarly small but statistically significant changes in most hemodynamic variables. There were 39 adverse events (26.0%). Adverse event rates increased using the composite metric of baseline PCWP and change in CI (P<0.01); elevated baseline PCWP and decreased CI after contrast correlated with the poorest prognosis. Adding both baseline PCWP and change in CI to the 5 risk models universally improved their predictive value (P≤0.02). In heart failure patients, the administration of contrast causes small but significant changes in hemodynamics. Calculating baseline PCWP with change in CI after contrast predicts adverse events and increases the predictive value of

  15. The second Sandia Fracture Challenge. Predictions of ductile failure under quasi-static and moderate-rate dynamic loading

    DOE PAGES

    Boyce, B. L.; Kramer, S. L. B.; Bosiljevac, T. R.; ...

    2016-03-14

    Ductile failure of structural metals is relevant to a wide range of engineering scenarios. Computational methods are employed to anticipate the critical conditions of failure, yet they sometimes provide inaccurate and misleading predictions. Challenge scenarios, such as the one presented in the current work, provide an opportunity to assess the blind, quantitative predictive ability of simulation methods against a previously unseen failure problem. Instead of evaluating the predictions of a single simulation approach, the Sandia Fracture Challenge relied on numerous volunteer teams with expertise in computational mechanics to apply a broad range of computational methods, numerical algorithms, and constitutive modelsmore » to the challenge. This exercise is intended to evaluate the state of health of technologies available for failure prediction. In the first Sandia Fracture Challenge, a wide range of issues were raised in ductile failure modeling, including a lack of consistency in failure models, the importance of shear calibration data, and difficulties in quantifying the uncertainty of prediction [see Boyce et al. (Int J Fract 186:5–68, 2014) for details of these observations]. This second Sandia Fracture Challenge investigated the ductile rupture of a Ti–6Al–4V sheet under both quasi-static and modest-rate dynamic loading (failure in ~ 0.1 s). Like the previous challenge, the sheet had an unusual arrangement of notches and holes that added geometric complexity and fostered a competition between tensile- and shear-dominated failure modes. The teams were asked to predict the fracture path and quantitative far-field failure metrics such as the peak force and displacement to cause crack initiation. Fourteen teams contributed blind predictions, and the experimental outcomes were quantified in three independent test labs. In addition, shortcomings were revealed in this second challenge such as inconsistency in the application of appropriate boundary

  16. The second Sandia Fracture Challenge. Predictions of ductile failure under quasi-static and moderate-rate dynamic loading

    SciTech Connect

    Boyce, B. L.; Kramer, S. L. B.; Bosiljevac, T. R.; Corona, E.; Moore, J. A.; Elkhodary, K.; Simha, C. H. M.; Williams, B. W.; Cerrone, A. R.; Nonn, A.; Hochhalter, J. D.; Bomarito, G. F.; Warner, J. E.; Carter, B. J.; Warner, D. H.; Ingraffea, A. R.; Zhang, T.; Fang, X.; Lua, J.; Chiaruttini, V.; Mazière, M.; Feld-Payet, S.; Yastrebov, V. A.; Besson, J.; Chaboche, J. -L.; Lian, J.; Di, Y.; Wu, B.; Novokshanov, D.; Vajragupta, N.; Kucharczyk, P.; Brinnel, V.; Döbereiner, B.; Münstermann, S.; Neilsen, M. K.; Dion, K.; Karlson, K. N.; Foulk, J. W.; Brown, A. A.; Veilleux, M. G.; Bignell, J. L.; Sanborn, S. E.; Jones, C. A.; Mattie, P. D.; Pack, K.; Wierzbicki, T.; Chi, S. -W.; Lin, S. -P.; Mahdavi, A.; Predan, J.; Zadravec, J.; Gross, A. J.; Ravi-Chandar, K.; Xue, L.

    2016-03-14

    Ductile failure of structural metals is relevant to a wide range of engineering scenarios. Computational methods are employed to anticipate the critical conditions of failure, yet they sometimes provide inaccurate and misleading predictions. Challenge scenarios, such as the one presented in the current work, provide an opportunity to assess the blind, quantitative predictive ability of simulation methods against a previously unseen failure problem. Instead of evaluating the predictions of a single simulation approach, the Sandia Fracture Challenge relied on numerous volunteer teams with expertise in computational mechanics to apply a broad range of computational methods, numerical algorithms, and constitutive models to the challenge. This exercise is intended to evaluate the state of health of technologies available for failure prediction. In the first Sandia Fracture Challenge, a wide range of issues were raised in ductile failure modeling, including a lack of consistency in failure models, the importance of shear calibration data, and difficulties in quantifying the uncertainty of prediction [see Boyce et al. (Int J Fract 186:5–68, 2014) for details of these observations]. This second Sandia Fracture Challenge investigated the ductile rupture of a Ti–6Al–4V sheet under both quasi-static and modest-rate dynamic loading (failure in ~ 0.1 s). Like the previous challenge, the sheet had an unusual arrangement of notches and holes that added geometric complexity and fostered a competition between tensile- and shear-dominated failure modes. The teams were asked to predict the fracture path and quantitative far-field failure metrics such as the peak force and displacement to cause crack initiation. Fourteen teams contributed blind predictions, and the experimental outcomes were quantified in three independent test labs. In addition, shortcomings were revealed in this second challenge such as inconsistency in the application of appropriate boundary conditions, need

  17. Model for end-stage liver disease predicts right ventricular failure in patients with left ventricular assist devices.

    PubMed

    Yost, Gardner L; Coyle, Laura; Bhat, Geetha; Tatooles, Antone J

    2016-03-01

    High rates of right ventricular failure continue to affect postoperative outcomes in patients implanted with left ventricular assist devices (LVADs). Development of right ventricular failure and implantation with right ventricular assist devices is known to be associated with significantly increased mortality. The model for end-stage liver disease (MELD) score is an effective means of evaluating liver dysfunction. We investigated the prognostic utility of postoperative MELD on post-LVAD implantation outcomes. MELD scores, demographic data, and outcomes including length of stay, survival, and postoperative right ventricular failure were collected for 256 patients implanted with continuous flow LVADs. Regression and Kaplan-Meier analyses were used to investigate the relationship between MELD and all outcomes. Increased MELD score was found to be an independent predictor of both right heart failure and necessity for RVAD implantation (OR 1.097, CI 1.040-1.158, p = 0.001; OR 1.121, CI 1.015, p = 0.024, respectively). Patients with RV failure and who underwent RVAD implantation had reduced postoperative survival compared to patients with RV dysfunction (no RV failure = 651.4 ± 609.8 days, RV failure = 392.6 ± 444.8 days, RVAD = 89.3 ± 72.8 days; p < 0.001). In conclusion, MELD can be used to reliably predict postoperative right heart failure and the necessity for RVAD implantation. Those patients with RV failure and RVADs experience significantly increased postoperative mortality compared to those without RV dysfunction.

  18. Predictions and Experimental Microstructural Characterization of High Strain Rate Failure Modes in Layered Aluminum Composites

    NASA Astrophysics Data System (ADS)

    Khanikar, Prasenjit

    Different aluminum alloys can be combined, as composites, for tailored dynamic applications. Most investigations pertaining to metallic alloy layered composites, however, have been based on quasi-static approaches. The dynamic failure of layered metallic composites, therefore, needs to be characterized in terms of strength, toughness, and fracture response. A dislocation-density based crystalline plasticity formulation, finite-element techniques, rational crystallographic orientation relations and a new fracture methodology were used to predict the failure modes associated with the high strain rate behavior of aluminum layered composites. Two alloy layers, a high strength alloy, aluminum 2195, and an aluminum alloy 2139, with high toughness, were modeled with representative microstructures that included precipitates, dispersed particles, and different grain boundary (GB) distributions. The new fracture methodology, based on an overlap method and phantom nodes, is used with a fracture criteria specialized for fracture on different cleavage planes. One of the objectives of this investigation, therefore, was to determine the optimal arrangements of the 2139 and 2195 aluminum alloys for a metallic layered composite that would combine strength, toughness and fracture resistance for high strain-rate applications. Different layer arrangements were investigated for high strain-rate applications, and the optimal arrangement was with the high toughness 2139 layer on the bottom, which provided extensive shear strain localization, and the high strength 2195 layer on the top for high strength resistance. The layer thickness of the bottom high toughness layer also affected the bending behavior of the roll-boned interface and the potential delamination of the layers. Shear strain localization, dynamic cracking and delamination were the mutually competing failure mechanisms for the layered metallic composite, and control of these failure modes can be optimized for high strain

  19. In Nonagenarians, Acute Kidney Injury Predicts In-Hospital Mortality, while Heart Failure Predicts Hospital Length of Stay

    PubMed Central

    Chao, Chia-Ter; Lin, Yu-Feng; Tsai, Hung-Bin; Hsu, Nin-Chieh; Tseng, Chia-Lin; Ko, Wen-Je

    2013-01-01

    Background/Aims The elderly constitute an increasing proportion of admitted patients worldwide. We investigate the determinants of hospital length of stay and outcomes in patients aged 90 years and older. Methods We retrospectively analyzed all admitted patients aged >90 years from the general medical wards in a tertiary referral medical center between August 31, 2009 and August 31, 2012. Patients’ clinical characteristics, admission diagnosis, concomitant illnesses at admission, and discharge diagnosis were collected. Each patient was followed until discharge or death. Multivariate logistic regression analysis was utilized to study factors associated with longer hospital length of stay (>7 days) and in-hospital mortality. Results A total of 283 nonagenarian in-patients were recruited, with 118 (41.7%) hospitalized longer than one week. Nonagenarians admitted with pneumonia (p = 0.04) and those with lower Barthel Index (p = 0.012) were more likely to be hospitalized longer than one week. Multivariate logistic regression analysis revealed that patients with lower Barthel Index (odds ratio [OR] 0.98; p = 0.021) and those with heart failure (OR 3.05; p = 0.046) had hospital stays >7 days, while patients with lower Barthel Index (OR 0.93; p = 0.005), main admission nephrologic diagnosis (OR 4.83; p = 0.016) or acute kidney injury (OR 30.7; p = 0.007) had higher in-hospital mortality. Conclusion In nonagenarians, presence of heart failure at admission was associated with longer hospital length of stay, while acute kidney injury at admission predicted higher hospitalization mortality. Poorer functional status was associated with both prolonged admission and higher in-hospital mortality. PMID:24223127

  20. Nucleation, growth and localisation of microcracks: implications for predictability of rock failure

    NASA Astrophysics Data System (ADS)

    Main, I. G.; Kun, F.; Pál, G.; Jánosi, Z.

    2016-12-01

    predictive power of forecasts of failure time in such media.

  1. Pulmonary congestion evaluated by lung ultrasound predicts decompensation in heart failure outpatients.

    PubMed

    Miglioranza, Marcelo H; Picano, Eugenio; Badano, Luigi P; Sant'Anna, Roberto; Rover, Marciane; Zaffaroni, Facundo; Sicari, Rosa; Kalil, Renato K; Leiria, Tiago L; Gargani, Luna

    2017-08-01

    Pulmonary congestion is the main cause of hospital admission among heart failure (HF) patients. Lung ultrasound (LUS) assessment of B-lines has been recently proposed as a reliable and easy tool for evaluating pulmonary congestion. To determine the prognostic value of LUS in predicting adverse events in HF outpatients. Single-center prospective cohort of 97 moderate-to-severe systolic HF patients (53±13years; 61% males) consecutively enrolled between November 2011 and October 2012. LUS evaluation was performed during the regular outpatient visit to evaluate the presence of pulmonary congestion, determined by B-lines number. Patients were followed up for 4months to assess admission due to acute pulmonary edema. During follow-up period (106±12days), 21 hospitalizations for acute pulmonary edema occurred. At Cox regression analysis, B-lines number≥30 (HR 8.62; 95%CI: 1.8-40.1; p=0.006) identified a group at high risk for acute pulmonary edema admission at 120days, and was the strongest predictor of events compared to other established clinical, laboratory and instrumental findings. No acute pulmonary edema occurred in patients without significant pulmonary congestion at LUS (number of B-lines<15). In a HF outpatient setting, B-line assessment by LUS identifies patients more likely to be admitted for decompensated HF in the following 4months. This simple evaluation could allow prompt therapy optimization in those patients who, although asymptomatic, carry a significant degree of extravascular lung water. Pulmonary congestion is the main cause of hospital admissions among heart failure patients. Lung ultrasound can be used as a reliable and easy way to evaluate pulmonary congestion through assessment of B-lines. In a cohort of heart failure outpatients, a B-lines cutoff≥30 (HR 8.62; 95%CI: 1.8-40.1) identified patients most likely to develop acute pulmonary edema at 120-days. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Central Venous Pressure After Coronary Artery Bypass Surgery: Does it Predict Postoperative Mortality or Renal Failure?

    PubMed Central

    Williams, Judson B.; Peterson, Eric D.; Wojdyla, Daniel; Ferguson, T. Bruce; Smith, Peter K.; Milano, Carmelo A.; Lopes, Renato D.

    2015-01-01

    Background While hemodynamic monitoring is often performed following coronary artery bypass grafting (CABG), the relationship between postoperative central venous pressure (CVP) measurement and clinical outcomes is unknown. Methods Detailed clinical data were analyzed from 2,390 randomly selected patients undergoing high risk CABG or CABG/valve at 55 hospitals participating in the Society of Thoracic Surgeons' National Cardiac Surgery Database from 2004 to 2005. Eligible patients underwent elective/urgent isolated CABG with an ejection fraction < 40%, or elective/urgent CABG at age ≥65 years with diabetes or a glomerular filtration rate 60 mL/min per 1.73 m2. Correlation between post-operative CVP and in-hospital / 30-day mortality and renal failure was assessed as a continuous variable, both unadjusted and after adjusting for important clinical factors using logistic regression modeling. Results Mean age was 72 years, 54% of patients had diabetes mellitus, 49% were urgent procedures, and mean cardiopulmonary bypass time was 105 minutes. Patients’ CVP 6 hours post-operation was strongly associated with in-hospital and 30 day mortality: odds ratio (OR) 1.5 (95% confidence interval [CI] 1.23, 1.87) for every 5 mmHg increase in CVP, p<0.0001. This association remained significant after risk-adjustment for cardiac index: adjusted OR 1.44 (95% CI 1.10, 1.89), p<0.01. A model adjusting for cardiac index also revealed increased incidence of mortality or renal failure: adjusted OR 1.5 (95% CI 1.28, 1.86) for every 5 mmHg increase in CVP, p<0.0001. Conclusion Patients’ central venous pressure at 6 hours following CABG surgery was highly predictive of operative mortality or renal failure, independent of cardiac index and other important clinical variables. Future studies will need to assess whether post-operative CVP can be used to guide intervention and improve outcomes. PMID:25035048

  3. A clinical score to predict acute renal failure after cardiac surgery.

    PubMed

    Thakar, Charuhas V; Arrigain, Susana; Worley, Sarah; Yared, Jean-Pierre; Paganini, Emil P

    2005-01-01

    The risk of mortality associated with acute renal failure (ARF) after open-heart surgery continues to be distressingly high. Accurate prediction of ARF provides an opportunity to develop strategies for early diagnosis and treatment. The aim of this study was to develop a clinical score to predict postoperative ARF by incorporating the effect of all of its major risk factors. A total of 33,217 patients underwent open-heart surgery at the Cleveland Clinic Foundation (1993 to 2002). The primary outcome was ARF that required dialysis. The scoring model was developed in a randomly selected test set (n = 15,838) and was validated on the remaining patients. Its predictive accuracy was compared by area under the receiver operating characteristic curve. The score ranges between 0 and 17 points. The ARF frequency at each score level in the validation set fell within the 95% confidence intervals (CI) of the corresponding frequency in the test set. Four risk categories of increasing severity (scores 0 to 2, 3 to 5, 6 to 8, and 9 to 13) were formed arbitrarily. The frequency of ARF across these categories in the test set ranged between 0.5 and 22.1%. The score was also valid in predicting ARF across all risk categories. The area under the receiver operating characteristic curve for the score in the test set was 0.81 (95% CI 0.78 to 0.83) and was similar to that in the validation set (0.82; 95% CI 0.80 to 0.85; P = 0.39). In conclusion, a score is valid and accurate in predicting ARF after open-heart surgery; along with increasing its clinical utility, the score can help in planning future clinical trials of ARF.

  4. PTCH1 expression at diagnosis predicts imatinib failure in chronic myeloid leukaemia patients in chronic phase.

    PubMed

    Alonso-Dominguez, Juan M; Grinfeld, Jacob; Alikian, Mary; Marin, David; Reid, Alistair; Daghistani, Mustafa; Hedgley, Corinne; O'Brien, Stephen; Clark, Richard E; Apperley, Jane; Foroni, Letizia; Gerrard, Gareth

    2015-01-01

    The tyrosine kinase inhibitor (TKI) imatinib has revolutionized the management of chronic myeloid leukaemia (CML). However, around 25% of patients fail to sustain an adequate response. We sought to identify gene-expression biomarkers that could be used to predict imatinib response. The expression of 29 genes, previously implicated in CML pathogenesis, were measured by TaqMan Low Density Array in 73 CML patient samples. Patients were divided into low and high expression for each gene and imatinib failure (IF), probability of achieving CCyR, progression free survival and CML related OS were compared by Kaplan-Meier and log-rank. Results were validated in a second cohort of 56 patients, with a further technical validation using custom gene-expression assays in a conventional RT-qPCR in a sub-cohort of 37 patients. Patients with low PTCH1 expression showed a worse clinical response for all variables in all cohorts. PTCH1 was the most significant predictor in the multivariate analysis compared with Sokal, age and EUTOS. PTCH1 expression assay showed the adequate sensitivity, specificity and predictive values to predict for IF. Given the different treatments available for CML, measuring PTCH1 expression at diagnosis may help establish who will benefit best from imatinib and who is better selected for second generation TKI. © 2014 Wiley Periodicals, Inc.

  5. The EST Model for Predicting Progressive Damage and Failure of Open Hole Bending Specimens

    NASA Technical Reports Server (NTRS)

    Joseph, Ashith P. K.; Waas, Anthony M.; Pineda, Evan J.

    2016-01-01

    Progressive damage and failure in open hole composite laminate coupons subjected to flexural loading is modeled using Enhanced Schapery Theory (EST). Previous studies have demonstrated that EST can accurately predict the strength of open hole coupons under remote tensile and compressive loading states. This homogenized modeling approach uses single composite shell elements to represent the entire laminate in the thickness direction and significantly reduces computational cost. Therefore, when delaminations are not of concern or are active in the post-peak regime, the version of EST presented here is a good engineering tool for predicting deformation response. Standard coupon level tests provides all the input data needed for the model and they are interpreted in conjunction with finite element (FE) based simulations. Open hole bending test results of three different IM7/8552 carbon fiber composite layups agree well with EST predictions. The model is able to accurately capture the curvature change and deformation localization in the specimen at and during the post catastrophic load drop event.

  6. A co-training-based approach for prediction of remaining useful life utilizing both failure and suspension data

    NASA Astrophysics Data System (ADS)

    Hu, Chao; Youn, Byeng D.; Kim, Taejin; Wang, Pingfeng

    2015-10-01

    Traditional data-driven prognostics often requires some amount of failure data for the offline training in order to achieve good accuracy for the online prediction. Failure data refer to condition monitoring data collected from the very beginning of an engineered system's lifetime till the occurrence of its failure. However, in many engineered systems, failure data are fairly expensive and time-consuming to obtain while suspension data are readily available. Suspension data refer to condition monitoring data acquired from the very beginning of an engineered system's lifetime till planned inspection or maintenance when the system is taken out of service. In such cases, it becomes essentially critical to utilize suspension data which may carry rich information regarding the degradation trend and help achieve more accurate remaining useful life (RUL) prediction. To this end, this paper proposes a co-training-based data-driven prognostic approach, denoted by COPROG, which uses two data-driven algorithms with each predicting RULs of suspension units for the other. After a suspension unit is chosen and its RUL is predicted by an individual algorithm, it becomes a virtual failure unit that is added to the training data set of the other individual algorithm. Results obtained from two case studies suggest that COPROG gives more accurate RUL prediction, as compared to any individual algorithm with no use of suspension data, and that COPROG can effectively exploit suspension data to improve the prognostic accuracy.

  7. A state-based approach to trend recognition and failure prediction for the Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Nelson, Kyle S.; Hadden, George D.

    1992-01-01

    A state-based reasoning approach to trend recognition and failure prediction for the Altitude Determination, and Control System (ADCS) of the Space Station Freedom (SSF) is described. The problem domain is characterized by features (e.g., trends and impending failures) that develop over a variety of time spans, anywhere from several minutes to several years. Our state-based reasoning approach, coupled with intelligent data screening, allows features to be tracked as they develop in a time-dependent manner. That is, each state machine has the ability to encode a time frame for the feature it detects. As features are detected, they are recorded and can be used as input to other state machines, creating a hierarchical feature recognition scheme. Furthermore, each machine can operate independently of the others, allowing simultaneous tracking of features. State-based reasoning was implemented in the trend recognition and the prognostic modules of a prototype Space Station Freedom Maintenance and Diagnostic System (SSFMDS) developed at Honeywell's Systems and Research Center.

  8. Failure Predictions for VHTR Core Components using a Probabilistic Contiuum Damage Mechanics Model

    SciTech Connect

    Fok, Alex

    2013-10-30

    The proposed work addresses the key research need for the development of constitutive models and overall failure models for graphite and high temperature structural materials, with the long-term goal being to maximize the design life of the Next Generation Nuclear Plant (NGNP). To this end, the capability of a Continuum Damage Mechanics (CDM) model, which has been used successfully for modeling fracture of virgin graphite, will be extended as a predictive and design tool for the core components of the very high- temperature reactor (VHTR). Specifically, irradiation and environmental effects pertinent to the VHTR will be incorporated into the model to allow fracture of graphite and ceramic components under in-reactor conditions to be modeled explicitly using the finite element method. The model uses a combined stress-based and fracture mechanics-based failure criterion, so it can simulate both the initiation and propagation of cracks. Modern imaging techniques, such as x-ray computed tomography and digital image correlation, will be used during material testing to help define the baseline material damage parameters. Monte Carlo analysis will be performed to address inherent variations in material properties, the aim being to reduce the arbitrariness and uncertainties associated with the current statistical approach. The results can potentially contribute to the current development of American Society of Mechanical Engineers (ASME) codes for the design and construction of VHTR core components.

  9. Failure behavior of internally pressurized flawed and unflawed steam generator tubing at high temperatures -- Experiments and comparison with model predictions

    SciTech Connect

    Majumdar, S.; Shack, W.J.; Diercks, D.R.; Mruk, K.; Franklin, J.; Knoblich, L.

    1998-03-01

    This report summarizes experimental work performed at Argonne National Laboratory on the failure of internally pressurized steam generator tubing at high temperatures ({le} 700 C). A model was developed for predicting failure of flawed and unflawed steam generator tubes under internal pressure and temperature histories postulated to occur during severe accidents. The model was validated by failure tests on specimens with part-through-wall axial and circumferential flaws of various lengths and depths, conducted under various constant and ramped internal pressure and temperature conditions. The failure temperatures predicted by the model for two temperature and pressure histories, calculated for severe accidents initiated by a station blackout, agree very well with tests performed on both flawed and unflawed specimens.

  10. Dexmedetomidine for tracheal extubation in deeply anesthetized adult patients after otologic surgery: a comparison with remifentanil.

    PubMed

    Fan, Qing; Hu, Chunbo; Ye, Min; Shen, Xia

    2015-07-23

    Remifentanil and dexmedetomidine are well known to suppress airway reflexes during airway procedures. Smooth tracheal extubation is important after otologic surgery. The purpose of this study is to compare the effectiveness of dexmedetomidine or remifentanil infusion for producing smooth tracheal extubation in deeply anesthetized patients after otologic surgery. Seventy-four ASA I-II adult patients (18-60 years old) scheduled for elective otologic surgery were randomly assigned to one of three groups: sevoflurane-remifentanil (Group SR, n = 25), sevoflurane-dexmedetomidine (0.5 μg/kg) (Group SD5, n = 24), or sevoflurane-dexmedetomidine (0.7 μg/kg) (Group SD7, n = 25). Remifentanil or dexmedetomidine were administered for 10 min at the end of surgery. The primary outcome was the rate of smooth extubation. Respiratory pattern, airway obstruction, hemodynamic and respiratory profiles, time to awake, rescue analgesics in the post-anesthesia care unit (PACU), and postoperative nausea and vomiting (PONV) were also recorded. The rate of smooth tracheal extubation as defined 1 min post-extubation was the same for Groups SR and SD7 (P > 0.05), but the rate of smooth extubation was lower for Group SD5 than for the other two groups (p < 0.05). During extubation, the respiratory rate was lower in Group SR than in both dexmedetomidine groups (p < 0.05). The hemodynamic profiles at extubation were similar between groups (p > 0.05), but the mean arterial pressure and heart rate were higher in Group SR at 10 and 15 min after extubation (p < 0.05). The incidence of airway obstruction and time to awake were comparable for all groups (p > 0.05). The need for rescue analgesic in the PACU was more common in Group SR than in both dexmedetomidine groups (P < 0.01). Compared to Group SR, both dexmedetomidine groups had less PONV on postoperative day 1 (p < 0.05). Combined with 1 MAC sevoflurane, dexmedetomidine 0.7 ug/kg and remifentanil

  11. Failure Mechanisms and Life Prediction of Thermal and Environmental Barrier Coatings under Thermal Gradients

    NASA Technical Reports Server (NTRS)

    Zju, Dongming; Ghosn, Louis J.; Miller, Robert A.

    2008-01-01

    Ceramic thermal and environmental barrier coatings (TEBCs) will play an increasingly important role in gas turbine engines because of their ability to further raise engine temperatures. However, the issue of coating durability is of major concern under high-heat-flux conditions. In particular, the accelerated coating delamination crack growth under the engine high heat-flux conditions is not well understood. In this paper, a laser heat flux technique is used to investigate the coating delamination crack propagation under realistic temperature-stress gradients and thermal cyclic conditions. The coating delamination mechanisms are investigated under various thermal loading conditions, and are correlated with coating dynamic fatigue, sintering and interfacial adhesion test results. A coating life prediction framework may be realized by examining the crack initiation and propagation driving forces for coating failure under high-heat-flux test conditions.

  12. Improved measurement of soil moisture using an ultrasonic waveguide to predict rainfall-induced slope failure

    NASA Astrophysics Data System (ADS)

    Tanaka, Katsuhiko; Hiraoka, Nobutaka; Nakano, Shunya; Kameda, Takuma; Fujimoto, Masamitsu; Fukagawa, Ryoichi

    2015-10-01

    Field monitoring of soil moisture and groundwater level is important to predict shallow slope failure stemming from heavy rainfall. We previously proposed a monitoring technique using ultrasonic waveguides in which soil moisture and groundwater levels are monitored on the basis of the intensity and propagation time of ultrasonic waves reflected from the underground soil surface, respectively. In field monitoring, the reflective intensity depends on the depth of monitoring points and the inhomogeneity of grains, so it has been difficult to examine the reflective intensity change quantitatively. In the present work, we propose improvements that will allow us to measure the intensity change quantitatively. Specifically, we utilize an ultrasonic waveguide of a constant length by using casing pipes with different lengths depending on the monitoring depth and cover the surface of coarse-grained soil with a homogeneous fine soil to obtain repeatable data for wetting and drying cycles. The positive effects of these improvements were confirmed by a field monitoring test.

  13. Predicting treatment failure in severe sepsis and septic shock: looking for the Holy Grail

    PubMed Central

    2013-01-01

    Procalcitonin has been proposed as a specific biomarker of bacterial infections and has been related to the severity of sepsis. The prognostic ability of the initial concentrations of procalcitonin in sepsis is controversial. Some studies find higher initial concentrations in non-survivors but others find no differences. Prognostic assessment based on follow-up of procalcitonin levels may be better than evaluation of the initial levels of procalcitonin. The persistence of elevated procalcitonin levels is indicative of poor prognosis and is associated with mortality. Procalcitonin kinetics could be a tool for assessing the evolution of severe sepsis and sepsis shock. Procalcitonin should find its place as a biomarker for predicting treatment failure of severe sepsis and septic shock. PMID:24004571

  14. A Novel Method for the Prediction of Critical Inclusion Size Leading to Fatigue Failure

    NASA Astrophysics Data System (ADS)

    Saberifar, S.; Mashreghi, A. R.

    2012-06-01

    The fatigue behavior of two commercial 30MnVS6 steels with similar microstructure and mechanical properties containing inclusions of different sizes were studied in the 107 cycles fatigue regime. The scanning electron microscopy (SEM) investigations of the fracture surfaces revealed that the nonmetallic inclusions are the main sources of fatigue crack initiation. Calculated according to the Murakami's model, the stress intensity factors were found to be suitable for the assessment of fatigue behavior. In this article, a new method is proposed for the prediction of the critical inclusion size, using Murakami's model. According to this method, a critical stress intensity factor was determined for the estimation of the critical inclusion size causing the fatigue failure.

  15. Prediction of reliability on thermoelectric module through accelerated life test and Physics-of-failure

    NASA Astrophysics Data System (ADS)

    Choi, Hyoung-Seuk; Seo, Won-Seon; Choi, Duck-Kyun

    2011-09-01

    Thermoelectric cooling module (TEM) which is electric device has a mechanical stress because of temperature gradient in itself. It means that structure of TEM is vulnerable in an aspect of reliability but research on reliability of TEM was not performed a lot. Recently, the more the utilization of thermoelectric cooling devices grows, the more the needs for life prediction and improvement are increasing. In this paper, we investigated life distribution, shape parameter of the TEM through accelerated life test (ALT). And we discussed about how to enhance life of TEM through the Physics-of-failure. Experimental results of ALT showed that the thermoelectric cooling module follows the Weibull distribution, shape parameter of which is 3.6. The acceleration model is coffin Coffin-Manson and material constant is 1.8.

  16. Is Brachial Artery Blood Flow Measured by Sonography During Early Postoperative Periods Predictive of Arteriovenous Fistula Failure in Hemodialysis Patients?

    PubMed

    Zhu, Yu-Li; Ding, Hong; Fan, Pei-Li; Gu, Qi-Lan; Teng, Jie; Wang, Wen-Ping

    2016-09-01

    The aim of our study was to determine a brachial artery blood flow level measured by sonography during early postoperative periods that is predictive of arteriovenous fistula failure in hemodialysis patients. Doppler sonography was used to estimate the blood flow in the brachial artery of 103 patients at 1 and 14 days after arteriovenous fistula creation. The performance of brachial artery blood flow during early postoperative periods for predicting fistula failure was evaluated, and optimal cutoff values were determined. During a 6-month follow-up, 85 fistulas were classified as mature, and 18 were classified as failures. The reproducibility of blood flow measurements in the brachial artery was good (intraclass correlation coefficient, 0.912). The blood flow in the failure group was significantly lower than that in the mature group at both 1 and 14 days after fistula creation (P < .05). During the first 2 postoperative weeks, the blood flow increased by 40.7% in the failure group versus 78.3% in the mature group. The areas under the receiver operating characteristic curves of brachial artery blood flow for predicting failure were 0.77 (95% confidence interval, 0.66-0.87; optimal cutoff value, 310 mL/min)at 1 day and 0.91 (95% confidence interval, 0.83-0.99; 413 mL/min) at 14 days after fistula creation. Brachial artery blood flow measured by sonography during early postoperative periods may be predictive of forearm fistula failure. Blood flow of less than 310 mL/min at 1 day and 413 mL/min at 14 days after fistula creation may indicate a risk of failure to mature.

  17. Native cardiac reserve predicts survival in acute post infarction heart failure in mice

    PubMed Central

    Täng, Margareta Scharin; Råmunddal, Truls; Lindbom, Malin; Omerovic, Elmir

    2007-01-01

    Cardiac reserve can be used to predict survival and outcome in patients with heart failure. The aim of this study was to investigate if native cardiac reserve could predict survival after myocardial infarction (MI) in mice. Method We investigated 27 healthy C57Bl6 mice (♂10–12 weeks old) with echocardiography using a high-frequency 15-MHz linear transducer. Investigations were performed both at rest and after pharmacological stress induced by dobutamine (1 μg/g body weight i.p.). The day after the echocardiography examination, a large MI was induced by ligation of the left anterior descending (LAD) coronary artery for evaluation of mortality rate. Results Two weeks after induction of MI, 7 mice were alive (26%). Evaluation of the difference between the surviving and deceased animals showed that the survivors had a better native ability to increase systolic performance (ΔLVESd -1.86 vs -1.28mm p = 0.02) upon dobutamine challenge, resulting in a better cardiac reserve (ΔFS 37 vs 25% p = 0.02 and ΔCO 0.27 vs -0.10 ml/min p = 0.02) and a better chronotropic reserve (ΔR-R interval -68 vs -19 ms p < 0.01). A positive relationship was found between ability to survive and both cardiac (p < 0.05) and chronotropic reserve (p < 0.05) when the mice were divided into three groups: survivors, surviving < 7 days, and surviving < 1 day. Conclusion We conclude that before MI induction the surviving animals had a better cardiac function compared with the deceased. This indicates that native cardiac and chronotropic reserve may be an important determinant and predictor of survival in the setting of large MI and post-infarction heart failure. PMID:18053159

  18. Prediction of failure to retain work 1 year after interdisciplinary functional restoration in occupational injuries.

    PubMed

    Brede, Emily; Mayer, Tom G; Gatchel, Robert J

    2012-02-01

    To identify risk factors for work retention (a patients' ability to both obtain and retain employment) at 1 year after treatment for a chronic disabling occupational musculoskeletal disorder (CDOMD). Prospective cohort study. Consecutive patients undergoing interdisciplinary functional restoration treatment in a regional rehabilitation referral center. A sample of 1850 consecutive CDOMD patients, who were admitted to and completed a functional restoration program, were subsequently classified as work retention or nonwork retention at a 1-year posttreatment evaluation. Not applicable. Measures, including medical evaluations, demographic and occupational data, psychosocial diagnostic evaluation, and validated measures of pain, disability, and depressive symptoms, were obtained at admission to, and discharge from, the program. Using a multivariate logistic regression analysis, the following variables were found to be significant predictors of failure to retain work: older age (odds ratio [OR]=1.84; 95% confidence interval [CI], 1.33-2.54), female sex (OR=1.46; 95% CI, 1.09-1.94), nonworking status at discharge (OR=1.65; 95% CI, 1.11-2.45), extreme disability at admission (OR=1.46; 95% CI, 1.06-2.00), antisocial personality disorder (OR=2.11; 95% CI, 1.09-4.08), receipt of government disability benefits at admission (OR=2.28; 95% CI, 1.06-4.89), and dependence on opiate pain medications (OR=1.43; 95% CI, 1.02-2.00). The final model improved prediction by 75% over assigning all patients to the larger (work retention) group. This study identified demographic, psychosocial, and occupational factors that were predictive of failure to retain work. These risk factors may be used to individualize treatment plans for CDOMD patients in order to provide optimal functional restoration. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  19. Strength Evaluation and Failure Prediction of Short Carbon Fiber Reinforced Nylon Spur Gears by Finite Element Modeling

    NASA Astrophysics Data System (ADS)

    Hu, Zhong; Hossan, Mohammad Robiul

    2013-06-01

    In this paper, short carbon fiber reinforced nylon spur gear pairs, and steel and unreinforced nylon spur gear pairs have been selected for study and comparison. A 3D finite element model was developed to simulate the multi-axial stress-strain behaviors of the gear tooth. Failure prediction has been conducted based on the different failure criteria, including Tsai-Wu criterion. The tooth roots, where has stress concentration and the potential for failure, have been carefully investigated. The modeling results show that the short carbon fiber reinforced nylon gear fabricated by properly controlled injection molding processes can provide higher strength and better performance.

  20. Polymorphisms of the beta1-adrenergic receptor predict exercise capacity in heart failure.

    PubMed

    Wagoner, Lynne E; Craft, Laura L; Zengel, Paul; McGuire, Nancy; Rathz, Deborah A; Dorn, Gerald W; Liggett, Stephen B

    2002-11-01

    Exercise performance in patients with congestive heart failure is partially dependent on cardiac beta1-adrenergic receptor (beta1AR) function. There are 2 common polymorphisms of the beta1AR gene that alter the encoded amino acids at positions 49 (Ser or Gly) and 389 (Gly or Arg) and alter receptor function in vitro. Their relevance to modification of cardiac function in heart failure is not known. Exercise testing was performed in 263 patients with idiopathic or ischemic cardiomyopathy (left ventricular ejection fraction approximately 25%). Potential associations were sought between beta1AR genotypes and the primary outcome variables of peak oxygen consumption (VO2), heart rate response, and exercise time. The major determinants of exercise capacity were the polymorphisms at position 389, where patients homozygous for Gly389 had significantly lower peak VO2 compared with those with Arg389 (14.5 +/- 0.6 vs 17.7 +/- 0.4 mL/kg/min, P =.006), despite similar clinical characteristics including left ventricular ejection fraction. Consistent with a gene dose-response, heterozygosity was associated with an intermediate response (16.9 +/- 0.6 mL/kg/min, P <.05). When position 49 genotypes were included, a graded relationship between the 5 2-locus haplotypes and VO2 was found. Two haplotypes displayed the most divergent peak VO2: homozygous Gly389/Ser49, and homozygous Arg389/Gly49 carriers (14.4 +/- 0.5 vs 18.2 +/- 0.8 mL/kg/min, P =.001). Genotype did not predict the heart rate response. The above results were independent of beta-blocker or other medication use, left ventricular ejection fraction, beta2AR genotype, or other demographic and clinical characteristics. beta1AR polymorphisms are a significant determinant of exercise capacity in patients with congestive heart failure. Early identification, by genetic testing for these polymorphisms, of heart failure patients at risk for development of depressed exercise capacity may be useful for initiation of specific therapy

  1. Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta-analysis

    PubMed Central

    Tangri, Navdeep; Grams, Morgan E.; Levey, Andrew S.; Coresh, Josef; Appel, Lawrence; Astor, Brad C.; Chodick, Gabriel; Collins, Allan J.; Djurdjev, Ognjenka; Elley, C. Raina; Evans, Marie; Garg, Amit X.; Hallan, Stein I.; Inker, Lesley; Ito, Sadayoshi; Jee, Sun Ha; Kovesdy, Csaba P.; Kronenberg, Florian; Lambers Heerspink, Hiddo J.; Marks, Angharad; Nadkarni, Girish N.; Navaneethan, Sankar D.; Nelson, Robert G.; Titze, Stephanie; Sarnak, Mark J.; Stengel, Benedicte; Woodward, Mark; Iseki, Kunitoshi

    2016-01-01

    Importance Identifying patients at risk of chronic kidney disease (CKD) progression may facilitate more optimal nephrology care. Kidney failure risk equations (KFREs) were previously developed and validated in two Canadian cohorts. Validation in other regions and in CKD populations not under the care of a nephrologist is needed. Objective To evaluate the accuracy of the KFREs across different geographic regions and patient populations through individual-participant data meta-analysis. Data Sources Thirty-one cohorts, including 721,357 participants with CKD Stages 3–5 in over 30 countries spanning 4 continents, were studied. These cohorts collected data from 1982 through 2014. Study Selection Cohorts participating in the CKD Prognosis Consortium with data on end-stage renal disease. Data Extraction and Synthesis Data were obtained and statistical analyses were performed between July 2012 and June 2015. Using the risk factors from the original KFREs, cohort-specific hazard ratios were estimated, and combined in meta-analysis to form new “pooled” KFREs. Original and pooled equation performance was compared, and the need for regional calibration factors was assessed. Main Outcome and Measure Kidney failure (treatment by dialysis or kidney transplantation). Results During a median follow-up of 4 years, 23,829 cases of kidney failure were observed. The original KFREs achieved excellent discrimination (ability to differentiate those who developed kidney failure from those who did not) across all cohorts (overall C statistic, 0.90 (95% CI 0.89–0.92) at 2 years and 0.88 (95% CI 0.86–0.90) at 5 years); discrimination in subgroups by age, race, and diabetes status was similar. There was no improvement with the pooled equations. Calibration (the difference between observed and predicted risk) was adequate in North American cohorts, but the original KFREs overestimated risk in some non-North American cohorts. Addition of a calibration factor that lowered the baseline

  2. Posthepatectomy portal vein pressure predicts liver failure and mortality after major liver resection on noncirrhotic liver.

    PubMed

    Allard, Marc-Antoine; Adam, René; Bucur, Pétru-Octav; Termos, Salah; Cunha, Antonio Sa; Bismuth, Henri; Castaing, Denis; Vibert, Eric

    2013-11-01

    To evaluate the predictive value of portal vein pressure (PVP) after major liver resection for posthepatectomy liver failure (PLF) and 90-day mortality in patients without cirrhosis. As elevated PVP is associated with liver failure after living donor liver transplantation, we hypothesized that the outcome after major hepatectomy may be influenced by posthepatectomy PVP. All patients without severe fibrosis or cirrhosis who underwent a major liver resection (≥3 segments) with an intraoperative measurement of PVP at the end of the procedure were included. Outcome was analyzed regarding 3 most widely used definitions of PLF: "50-50" criteria, peak of serum bilirubin greater than 120 μmol/L, and grade C PLF proposed by the International Study Group of Liver Surgery (ISGLS). Receiver operating characteristic curves and logistic regression model were used to determine the optimal cutoff of PVP and independent risk factors of PLF. The study population consisted of 277 patients. Posthepatectomy PVP was gradually correlated with the PLF risk. Probability for PLF was nil when PVP was 10 mm Hg or less, ranges from 13% to 16%, depending on PLF definitions, when PVP was 20 mm Hg, and from 24% to 33% when PVP was 30 mm Hg. The optimal value of posthepatectomy PVP to predict PLF was 22 mm Hg when considering the "50-50" criteria and grade C PLF (proposed by the International Study Group of Liver Surgery). A value of 21 mm Hg best predicted PLF defined by peak of serum bilirubin greater than 120 μmol/L and 90-day mortality. At multivariate analysis, posthepatectomy PVP remained an independent predictor of PLF as well as the extent of resection, intraoperative transfusion, and the presence of diabetes. The 90-day mortality was associated with PVP greater than 21 mm Hg, older than 70 years, and intraoperative transfusion. Posthepatectomy PVP is an independent predictive factor of PLF and of 90-day mortality after major liver resection in patients without cirrhosis

  3. To what extent can linear finite element models of human femora predict failure under stance and fall loading configurations?

    PubMed

    Schileo, Enrico; Balistreri, Luca; Grassi, Lorenzo; Cristofolini, Luca; Taddei, Fulvia

    2014-11-07

    Proximal femur strength estimates from computed tomography (CT)-based finite element (FE) models are finding clinical application. Published models reached a high in-vitro accuracy, yet many of them rely on nonlinear methodologies or internal best-fitting of parameters. The aim of the present study is to verify to what extent a linear FE modelling procedure, fully based on independently determined parameters, can predict the failure characteristics of the proximal femur in stance and sideways fall loading configurations. Fourteen fresh-frozen cadaver femora were CT-scanned. Seven femora were tested to failure in stance loading conditions, and seven in fall. Fracture was monitored with high-speed videos. Linear FE models were built from CT images according to a procedure already validated in the prediction of strains. An asymmetric maximum principal strain criterion (0.73% tensile, 1.04% compressive limit) was used to define a node-based risk factor (RF). FE-predicted failure load, mode (tensile/compressive) and location were determined from the first node reaching RF=1. FE-predicted and measured failure loads were highly correlated (R(2)=0.89, SEE=814N). In all specimens, FE models correctly identified the failure mode (tensile in stance, compressive in fall) and the femoral region where fracture started (supero-lateral neck aspect). The location of failure onset was accurately predicted in eight specimens. In summary, a simple FE model, adaptable in the future to multiple loads (e.g. including muscles), was highly correlated with experimental failure in two loading conditions on specimens ranging from normal to osteoporotic. Thus, it can be suitable for use in clinical studies.

  4. [Contribution of neuromonitoring to the safety of tracheal extubation after total thyroidectomy. Prospective study with needle electrodes].

    PubMed

    Pardal-Refoyo, J L; Cuello-Azcárate, J J; Ochoa-Sangrador, C

    2013-12-01

    Bilateral laryngeal paralysis cause serious respiratory complications. In thyroid surgery, neuromonitoring helps in identifying the recurrent laryngeal nerve, reports on its functioning at the end of surgery, supports decision making, and may reduce the risk of bilateral paralysis. Our objective was to estimate the influence of neuromonitoring in operative strategy and extubation safety in total thyroidectomy. A non-randomized prospective study was conducted on 210 patients undergoing total thyroidectomy (420 laryngeal nerves stimulated included). We collected qualitative neuromonitoring variables (presence or absence of final signal after stimulation of the vagus nerve), and postoperative indirect laryngoscopy (normal motility or paralysis), performed until 3rd day after the surgery. The accuracy of the test was 99.5% (95% CI 98.3 to 99.9). The positive predictive value was 100% (95% CI 99.1 to 100), which showed the high ability of neuromonitoring to predict paralysis in case of loss of signal, and the negative predictive value was 99.5% (95% CI 98.3 to 99.9), which indicated its predictive capacity for normal motility when there is a normal signal. In our group of patients, recurrent laryngeal nerve monitoring was useful in total thyroidectomy as it provided information on the prognosis of laryngeal motility, and helped in making decisions during surgery when there was signal loss. Due to the risk of serious respiratory complications due to bilateral recurrent laryngeal nerve paralysis, we opted for the performing of the 2-stage total thyroidectomy in case of signal loss in the first lobectomy. Thereby, neuromonitoring contributed to the safety of the airway in tracheal extubation, aiding in the prevention of a possible bilateral laryngeal paralysis. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

  5. Pulmonary artery pulsatility index predicts right ventricular failure after left ventricular assist device implantation.

    PubMed

    Kang, Guson; Ha, Richard; Banerjee, Dipanjan

    2016-01-01

    Right ventricular failure (RVF) is a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. The pulmonary artery pulsatility index (PAPi) is a novel hemodynamic index that predicts RVF in the setting of myocardial infarction, although it has not been shown to predict RVF after LVAD implantation. We performed a retrospective, single-center analysis to examine the utility of the PAPi in predicting RVF and RV assist device (RVAD) implantation in 85 continuous-flow LVAD recipients. We performed a multivariate logistic regression analysis incorporating previously identified predictors of RVF after LVAD placement, including clinical and echocardiographic variables, to determine the independent effect of PAPi in predicting RVF or RVAD after LVAD placement. In this cohort, the mean PAPi was 3.4 with a standard deviation of 2.9. RVF occurred in 33% of patients, and 11% required a RVAD. Multivariate analysis, adjusting for age, blood urea nitrogen (BUN), and Interagency Registry for Mechanically Assisted Circulatory Support profile, revealed that higher PAPi was independently associated with a reduced risk of RVAD placement (odds ratio [OR], 0.30; 95% confidence interval [CI], 0.07-0.89). This relationship did not change significantly when echocardiographic measures were added to the analysis. Stratifying the analysis by the presence of inotropes during catheterization revealed that PAPi was more predictive of RVAD requirement when measured on inotropes (OR, 0.21; 95% CI, 0.02-0.97) than without (OR, 0.49; 95% CI, 0.01-1.94). Furthermore, time from catheterization to LVAD did not significantly affect the predictive value of the PAPi (maximum time, 6 months). Receiver operating characteristic curve analysis revealed that optimal sensitivity and specificity were achieved using a PAPi threshold of 2.0. In LVAD recipients, the PAPi is an independent predictor of RVF and the need for RVAD support after LVAD implantation. This index

  6. Sufentanil infusion before extubation suppresses coughing on emergence without delaying extubation time and reduces postoperative analgesic requirement without increasing nausea and vomiting after desflurane anesthesia

    PubMed Central

    Lee, Jea Yeun; Lim, Byung Gun; Park, Hye Yoon

    2012-01-01

    Background Coughing, hypertension, tachycardia, and even laryngospasm can occur due to airway irritation during emergence from anesthesia. We investigated the effect of maintaining a sufentanil infusion during emergence from anesthesia by evaluating the incidence of cough and recovery profiles at extubation. Methods In total, eighty-four patients undergoing an elective laparoscopic hysterectomy were randomly divided into two sufentanil groups and a control group. During emergence, sufentanil was administered in the sufentanil groups at a rate of 0.2 µg/kg/hr (Group S1) or 0.3 µg/kg/hr (Group S2), and saline was administered to the control group. Cough score, hemodynamic changes, and recovery profiles, such as duration from skin closure to a bispectral index of 80, to eye opening at verbal command, to tracheal extubation and the total duration of study solution infusion, were recorded. The pain score, the total volume of administered patient-controlled analgesia (PCA), and the postoperative nausea and vomiting (PONV) score were evaluated 1, 6, and 24 hours after surgery. Results Groups S1 and S2 showed significantly lower cough scores and smaller hemodynamic changes on extubation compared to Group C. Recovery profiles showed no significant differences among the three groups. Pain score, PONV at 1 hour postoperatively, and the total volume of PCA administered at all evaluation times were significantly lower in Groups S1 and S2 than in the control group. However, pain score, and PONV at 6 hours and 24 hours postoperatively showed no significant differences. Conclusions A sufentanil infusion (0.2-0.3 µg/kg/hr) during emergence from desflurane anesthesia may suppress coughing on extubation in patients with body mass indexes (BMI) of 21-26 without delaying extubation time. It may also reduce the postoperative analgesic requirement without increasing PONV. PMID:22778885

  7. Diastolic Heart Failure Predicted by Left Atrial Expansion Index in Patients with Severe Diastolic Dysfunction

    PubMed Central

    Hsiao, Shih-Hung; Chiou, Kuan-Rau

    2016-01-01

    Background Left atrial (LA) echocardiographic parameters are increasingly used to predict clinically relevant cardiovascular events. The study aims to evaluate the LA expansion index (LAEI) for predicting diastolic heart failure (HF) in patients with severe left ventricular (LV) diastolic dysfunction. Methods This prospective study enrolled 162 patients (65% male) with preserved LV systolic function and severe diastolic dysfunction (132 grade 2 patients, 30 grade 3 patients). All patients had sinus rhythm at enrollment. The LAEI was calculated as (Volmax - Volmin) x 100% / Volmin, where Volmax was defined as maximal LA volume and Volmin was defined as minimal volume. The endpoint was hospitalization for HF withp reserved LV ejection fraction (HFpEF). Results The median follow-up duration was 2.9 years. Fifty-four patients had cardiovascular events, including 41 diastolic and 8 systolic HF hospitalizations. In these 54 patients, 13 in-hospital deaths and 5 sudden out-of-hospital deaths occurred. Multivariate analyses revealed that HFpEF was associated with LAEI.and atrial fibrillation during follow-up. For predicting HFpEF, the LAEI had a hazard ratio of 1.197per 10% decrease. In patients who had HFpEF events, the LAEI significantly (P< 0.0001) decreased from 69±18% to 39±11% during hospitalization. Although the LAEI improved during follow-up (53±13%), it did not return to baseline. Conclusions The LAEI predicts HFpEF in patients with severe diastolic dysfunction; it worsens during HFpEF events and partially recovers during followup. PMID:27622475

  8. A Bayesian Model to Predict Right Ventricular Failure following Left Ventricular Assist Device Therapy

    PubMed Central

    Loghmanpour, Natasha A.; Kormos, Robert L.; Kanwar, Manreet K.; Teuteberg, Jeffrey J.; Murali, Srinivas; Antaki, James F.

    2016-01-01

    Background Right ventricular failure (RVF) continues to be a major adverse event following left ventricular assist device (LVAD) implantation. This study investigates the use of a Bayesian statistical model to address the limited predictive capacity of existing risk scores derived from multivariate analyses. This is based on the hypothesis that it is necessary to consider the inter-relationships and conditional probabilities amongst independent variables to achieve sufficient statistical accuracy. Methods The data used for this study was derived from 10,909 adult patients from INTERMACS who had a primary LVAD from December 2006 – March 2014. An initial set of 176 pre-implant variables were considered. RVF post-implant was categorized as acute (<48 hours), early (48 hours–14 days) and late (>14 days) in onset. For each of these endpoints, a separate tree-augmented Naïve Bayes model was constructed using the most predictive variables using an open source Bayesian inference engine (SMILE.) Results The acute RVF model consisted of 33 variables, including: systolic pulmonary artery pressure (PAP), white blood cell count, left ventricular ejection fraction, cardiac index, sodium levels, and lymphocyte percentage. The early RVF model consisted of 34 variables, including systolic PAP, pre-albumin, LDH, INTERMACS profile, right ventricular ejection fraction, pro-B-type natriuretic peptide, age, heart rate, tricuspid regurgitation and BMI. The late RVF model included 33 variables and was mostly predicted by peripheral vascular resistance, MELD score, albumin, lymphocyte percentage, mean PAP and diastolic PAP. The accuracies of all the Bayesian models were between 91–97%, AUC between 0.83–0.90 sensitivity of 90% and specificity between 98–99%, significantly outperforming previously published risk scores. Conclusion A Bayesian prognostic model of RVF, based on the large, multi-center INTERMACS registry provided highly accurate predictions of acute, early, and late

  9. Serum Parathyroid Hormone Levels Predict Discharge and Readmission for Heart Failure.

    PubMed

    Wu, Gangyong; Wang, Xiaoying; Wang, Xiao; Jiang, Haibing; Wang, Lulu; Wang, Tianxiao; Liu, Jie; An, Dongmei; Cao, Li; Xia, Yang; Zong, Gangjun

    2016-06-01

    Parathyroid hormone (PTH) levels are useful as a prognostic factor of chronic heart failure (HF) and can predict hospitalization for HF. It is unknown whether serum PTH levels in hospitalized patients with HF can predict discharge and if admission, discharge, or change from admission to discharge PTH measure is the most important predictor of readmission and/or death. A total of 125 consecutive hospitalized patients with HF were enrolled into this study. The receiver operating characteristic (ROC) curves indicated the predicted values of PTH for readmission due to HF and the optimal cutoff points of PTH levels for discharge. The binary logistic regression model indicated an association between PTH levels and readmission due to HF. The PTH level on admission was positively correlated with the New York Heart Association class and N-terminal pro-B-type natriuretic peptide level. The ROC curves showed that the PTH level at discharge (PTHdis) was of predictive value for readmission within 1 year due to HF. A PTHdis level <45.2 pg/mL was the best cutoff point for discharge, with a sensitivity of 72.1%, specificity of 61.5%, and area under the ROC curve of 0.693 (95% confidence interval [CI] 0.598-0.788). The results of logistic regression analysis showed that PTHdis had an odds ratio of 1.035 for readmission due to HF (95% CI 1.005-1.067). Serum PTH levels in hospitalized patients with HF were shown to be an independent predictor of discharge and PTHdis was the best predictor of readmission and/or death within 1 year due to HF.

  10. Transvaginal ultrasonographic cervical measurement in predicting failed labor induction and cesarean delivery for failure to progress in nulliparous women.

    PubMed

    Park, Kyo Hoon

    2007-08-01

    The aim of this study was to evaluate the value of transvaginal sonographic cervical measurement in predicting failed labor induction and cesarean delivery for failure to progress in nulliparous women. One hundred and sixty-one women scheduled for labor induction underwent transvaginal ultrasonography and digital cervical examinations. Logistic regression demonstrated that cervical length and gestational age at induction, but not the Bishop score, significantly and independently predicted failed labor induction. According to the receiver operating characteristic curves analysis, the best cut-off value of cervical length for predicting failed labor induction was 28 mm, with a sensitivity of 62% and a specificity of 60%. In terms of the likelihood of a cesarean delivery for failure to progress as the outcome variable, logistic regression indicated that maternal height and birth weight, but not cervical length or Bishop score, were significantly and independently associated with an increased risk of cesarean delivery for failure to progress. Transvaginal sonographic measurements of cervical length thus independently predicted failed labor induction in nulliparous women. However, the relatively poor predictive performance of this test undermines its clinical usefulness as a predictor of failed labor induction. Moreover, cervical length appears to have a poor predictive value for the likelihood of a cesarean delivery for failure to progress.

  11. Decreased physical activity predicts cognitive dysfunction and reduced cerebral blood flow in heart failure.

    PubMed

    Alosco, Michael L; Spitznagel, Mary Beth; Cohen, Ronald; Raz, Naftali; Sweet, Lawrence H; Josephson, Richard; Hughes, Joel; Rosneck, Jim; Gunstad, John

    2014-04-15

    Cognitive impairment in heart failure (HF) is believed to result from brain hypoperfusion subsequent to cardiac dysfunction. Physical inactivity is prevalent in HF and correlated with reduced cardiac and cognitive function. Yet, no longitudinal studies have examined the neurocognitive effects of physical inactivity in HF. The current study examined whether reduced physical activity increases risk for cognitive impairment and brain hypoperfusion over time in HF. At baseline and 12 months later, 65 HF patients underwent neuropsychological testing, transcranial Doppler ultrasonography, and were asked to wear an accelerometer for seven days. Lower baseline step count and less time spent in moderate free-living activity best predicted worse attention/executive function and decreased cerebral perfusion at the 12-month follow-up. Decreased baseline cerebral perfusion also emerged as a strong predictor of poorer 12-month attention/executive function. Lower physical activity predicted worse cognition and cerebral perfusion 12 months later in HF. Physical inactivity in HF may contribute to cognitive impairment and exacerbate risk for conditions such as Alzheimer's disease. Larger studies are needed to elucidate the mechanisms by which physical inactivity leads to cognitive dysfunction in HF, including clarification of the role of cerebral hypoperfusion. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Biomarkers to Predict Reverse Remodeling and Myocardial Recovery in Heart Failure.

    PubMed

    Motiwala, Shweta R; Gaggin, Hanna K

    2016-10-01

    Left ventricular remodeling appears to be a critical link between cardiac injury and the development and progression of heart failure with reduced ejection fraction (HFrEF). Several drug and device therapies that modify and reverse the remodeling process in patients with HFrEF are closely associated with improvement in clinical outcomes. Reverse remodeling, including partial or complete recovery of systolic function and structure, is possible but its determinants are incompletely understood. Methods to predict reverse remodeling in response to therapy are not well defined. Though non-invasive imaging techniques remain the most widely used methods of assessing reverse remodeling, serum biomarkers are now being investigated as more specific, mechanistically driven, and clinically useful predictors of reverse remodeling. Biomarkers that reflect myocyte stretch and stress, myocyte injury and necrosis, inflammation and fibrosis, and extracellular matrix turnover may be particularly valuable for predicting pathophysiologic changes and prognosis in individual patients. Their use may ultimately allow improved application of precision medicine in chronic HF.

  13. The failure analysis and lifetime prediction for the solder joint of the magnetic head

    NASA Astrophysics Data System (ADS)

    Xiao, Xianghui; Peng, Minfang; Cardoso, Jaime S.; Tang, Rongjun; Zhou, YingLiang

    2015-02-01

    Micro-solder joint (MSJ) lifetime prediction methodology and failure analysis (FA) are to assess reliability by fatigue model with a series of theoretical calculations, numerical simulation and experimental method. Due to shortened time of solder joints on high-temperature, high-frequency sampling error that is not allowed in productions may exist in various models, including round-off error. Combining intermetallic compound (IMC) growth theory and the FA technology for the magnetic head in actual production, this thesis puts forward a new growth model to predict life expectancy for solder joint of the magnetic head. And the impact of IMC, generating from interface reaction between slider (magnetic head, usually be called slider) and bonding pad, on mechanical performance during aging process is analyzed in it. By further researching on FA of solder ball bonding, thesis chooses AuSn4 growth model that affects least to solder joint mechanical property to indicate that the IMC methodology is suitable to forecast the solder lifetime. And the diffusion constant under work condition 60 °C is 0.015354; the solder lifetime t is 14.46 years.

  14. Persistent pulmonary congestion before discharge predicts rehospitalization in heart failure: a lung ultrasound study.

    PubMed

    Gargani, Luna; Pang, P S; Frassi, F; Miglioranza, M H; Dini, F L; Landi, P; Picano, E

    2015-09-04

    B-lines evaluated by lung ultrasound (LUS) are the sonographic sign of pulmonary congestion, a major predictor of morbidity and mortality in patients with heart failure (HF). Our aim was to assess the prognostic value of B-lines at discharge to predict rehospitalization at 6 months in patients with acute HF (AHF). A prospective cohort of 100 patients admitted to a Cardiology Department for dyspnea and/or clinical suspicion of AHF were enrolled (mean age 70 ± 11 years). B-lines were evaluated at admission and before discharge. Subjects were followed-up for 6-months after discharge. Mean B-lines at admission was 48 ± 48 with a statistically significant reduction before discharge (20 ± 23, p < .0001). During follow-up, 14 patients were rehospitalized for decompensated HF. The 6-month event-free survival was highest in patients with less B-lines (≤ 15) and lowest in patients with more B-lines (> 15) (log rank χ(2) 20.5, p < .0001). On multivariable analysis, B-lines > 15 before discharge (hazard ratio [HR] 11.74; 95 % confidence interval [CI] 1.30-106.16) was an independent predictor of events at 6 months. Persistent pulmonary congestion before discharge evaluated by ultrasound strongly predicts rehospitalization for HF at 6-months. Absence or a mild degree of B-lines identify a subgroup at extremely low risk to be readmitted for HF decompensation.

  15. Multimarker proteomic profiling for the prediction of cardiovascular mortality in patients with chronic heart failure.

    PubMed

    Lemesle, Gilles; Maury, Fleur; Beseme, Olivia; Ovart, Lionel; Amouyel, Philippe; Lamblin, Nicolas; de Groote, Pascal; Bauters, Christophe; Pinet, Florence

    2015-01-01

    Risk stratification of patients with systolic chronic heart failure (HF) is critical to better identify those who may benefit from invasive therapeutic strategies such as cardiac transplantation. Proteomics has been used to provide prognostic information in various diseases. Our aim was to investigate the potential value of plasma proteomic profiling for risk stratification in HF. A proteomic profiling using surface enhanced laser desorption ionization - time of flight - mass spectrometry was performed in a case/control discovery population of 198 patients with systolic HF (left ventricular ejection fraction <45%): 99 patients who died from cardiovascular cause within 3 years and 99 patients alive at 3 years. Proteomic scores predicting cardiovascular death were developed using 3 regression methods: support vector machine, sparse partial least square discriminant analysis, and lasso logistic regression. Forty two ion m/z peaks were differentially intense between cases and controls in the discovery population and were used to develop proteomic scores. In the validation population, score levels were higher in patients who subsequently died within 3 years. Similar areas under the curves (0.66 - 0.68) were observed for the 3 methods. After adjustment on confounders, proteomic scores remained significantly associated with cardiovascular mortality. Use of the proteomic scores allowed a significant improvement in discrimination of HF patients as determined by integrated discrimination improvement and net reclassification improvement indexes. In conclusion, proteomic analysis of plasma proteins may help to improve risk prediction in HF patients.

  16. The failure analysis and lifetime prediction for the solder joint of the magnetic head

    NASA Astrophysics Data System (ADS)

    Xiao, Xianghui; Peng, Minfang; Cardoso, Jaime S.; Tang, Rongjun; Zhou, YingLiang

    2014-09-01

    Micro-solder joint (MSJ) lifetime prediction methodology and failure analysis (FA) are to assess reliability by fatigue model with a series of theoretical calculations, numerical simulation and experimental method. Due to shortened time of solder joints on high-temperature, high-frequency sampling error that is not allowed in productions may exist in various models, including round-off error. Combining intermetallic compound (IMC) growth theory and the FA technology for the magnetic head in actual production, this thesis puts forward a new growth model to predict life expectancy for solder joint of the magnetic head. And the impact of IMC, generating from interface reaction between slider (magnetic head, usually be called slider) and bonding pad, on mechanical performance during aging process is analyzed in it. By further researching on FA of solder ball bonding, thesis chooses AuSn4 growth model that affects least to solder joint mechanical property to indicate that the IMC methodology is suitable to forecast the solder lifetime. And the diffusion constant under work condition 60 °C is 0.015354; the solder lifetime t is 14.46 years.

  17. Nutritional Risk Index predicts mortality in hospitalized advanced heart failure patients.

    PubMed

    Adejumo, Oluwayemisi L; Koelling, Todd M; Hummel, Scott L

    2015-11-01

    Hospitalized advanced heart failure (HF) patients are at high risk for malnutrition and death. The Nutritional Risk Index (NRI) is a simple, well-validated tool for identifying patients at risk for nutrition-related complications. We hypothesized that, in advanced HF patients from the ESCAPE (Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness) trial, the NRI would improve risk discrimination for 6-month all-cause mortality. We analyzed the 160 ESCAPE index admission survivors with complete follow-up and NRI data, calculated as follows: NRI = (1.519 × discharge serum albumin [in g/dl]) + (41.7 × discharge weight [in kg] / ideal body weight [in kg]); as in previous studies, if discharge weight is greater than ideal body weight (IBW), this ratio was set to 1. The previously developed ESCAPE mortality model includes: age; 6-minute walk distance; cardiopulmonary resuscitation/mechanical ventilation; discharge β-blocker prescription and diuretic dose; and discharge serum sodium, blood urea nitrogen and brain natriuretic peptide levels. We used Cox proportional hazards modeling for the outcome of 6-month all-cause mortality. Thirty of 160 patients died within 6 months of hospital discharge. The median NRI was 96 (IQR 91 to 102), reflecting mild-to-moderate nutritional risk. The NRI independently predicted 6-month mortality, with adjusted HR 0.60 (95% CI 0.39 to 0.93, p = 0.02) per 10 units, and increased Harrell's c-index from 0.74 to 0.76 when added to the ESCAPE model. Body mass index and NRI at hospital admission did not predict 6-month mortality. The discharge NRI was most helpful in patients with high (≥ 20%) predicted mortality by the ESCAPE model, where observed 6-month mortality was 38% in patients with NRI < 100 and 14% in those with NRI > 100 (p = 0.04). The NRI is a simple tool that can improve mortality risk stratification at hospital discharge in hospitalized patients with advanced HF. Published by Elsevier

  18. Incidence and Risk Factors for Cardiovascular Collapse After Unplanned Extubations in the Pediatric ICU.

    PubMed

    Lucas da Silva, Paulo Sérgio; Fonseca, Marcelo Cunio Machado

    2017-07-01

    Cardiovascular collapse is a life-threatening event after unplanned extubations (UEs) in the pediatric ICU (PICU). However, there is a paucity of pediatric studies assessing this complication. We sought to assess the incidence, risk factors, and outcome of cardiovascular collapse after UEs in PICU patients. All children who had been mechanically ventilated for ≥12 h were prospectively tracked for UEs over an 8-y period. Subjects were included in the study if they were between ages 1 month and 16 y and had experienced UE. They were analyzed in 2 groups: those with cardiovascular collapse (defined as the need for cardiopulmonary resuscitation or circulatory dysfunction immediately after UE) and those with no cardiovascular collapse. Of the 847 subjects, 109 UEs occurred in 14,293 intubation days (0.76 UEs/100 intubation days), with 21 subjects (19.2%) experiencing cardiovascular collapse, of which 10 required cardiopulmonary resuscitation. Compared with subjects without cardiovascular collapse after UE, children with cardiovascular collapse were younger (<6 months old), with respiratory failure from lower respiratory tract diseases, lower PaO2/FIO2 (218 vs 282 mm Hg), and higher oxygenation indices (5.5 vs 3.5) before UE events. Logistic regression revealed that only an age ≤6 months old was strongly associated with cardiovascular collapse (odds ratio 3.4, P = .03). There were no differences between cardiovascular collapse and non-cardiovascular collapse subjects regarding the length of hospital stay, ventilator-associated pneumonia rate, and mortality. Cardiovascular collapse is a frequent complication of UEs, particularly in the youngest children. Specific bundles to prevent UEs may reduce morbidity related to these events. Copyright © 2017 by Daedalus Enterprises.

  19. Life Prediction and Classification of Failure Modes in Solid State Luminaires Using Bayesian Probabilistic Models

    SciTech Connect

    Lall, Pradeep; Wei, Junchao; Sakalaukus, Peter

    2014-05-27

    A new method has been developed for assessment of the onset of degradation in solid state luminaires to classify failure mechanisms by using metrics beyond lumen degradation that are currently used for identification of failure. Luminous Flux output, Correlated Color Temperature Data on Philips LED Lamps has been gathered under 85°C/85%RH till lamp failure. The acquired data has been used in conjunction with Bayesian Probabilistic Models to identify luminaires with onset of degradation much prior to failure through identification of decision boundaries between lamps with accrued damage and lamps beyond the failure threshold in the feature space. In addition luminaires with different failure modes have been classified separately from healthy pristine luminaires. It is expected that, the new test technique will allow the development of failure distributions without testing till L70 life for the manifestation of failure.

  20. A Comprehensive Method for Predicting Fatal Liver Failure of Patients With Liver Cancer Resection

    PubMed Central

    Li, Jiangfa; Lei, Biao; Nie, Xingju; Lin, Linku; Tahir, Syed Abdul; Shi, Wuxiang; Jin, Junfei; He, Songqing

    2015-01-01

    Abstract There are many methods to assess liver function, but none of them has been verified as fully effective. The purpose of this study is to establish a comprehensive method evaluating perioperative liver reserve function (LRF) in patients with primary liver cancer (PLC). In this study, 310 PLC patients who underwent liver resection were included. The cohort was divided into a training set (n = 235) and a validation set (n = 75). The factors affecting postoperative liver dysfunction (POLD) during preoperative, intraoperative, and postoperative periods were confirmed by logistic regression analysis. The equation for calculating the preoperative liver functional evaluation index (PLFEI) was established; the cutoff value of PLFEI determined through analysis by receiver-operating characteristic curve was used to predict postoperative liver function. The data showed that body mass index, international normalized ratio, indocyanine green (ICG) retention rate at 15 minutes (ICGR15), ICG elimination rate, standard remnant liver volume (SRLV), operative bleeding volume (OBV), blood transfusion volume, and operative time were statistically different (all P < 0.05) between 2 groups of patients with and without POLD. The relationship among PLFEI, ICGR15, OBV, and SRLV is expressed as an equation of “PLFEI = 0.181 × ICGR15 + 0.001 × OBV − 0.008 × SRLV.” The cutoff value of PLFEI to predict POLD was −2.16 whose sensitivity and specificity were 90.3% and 73.5%, respectively. However, when predicting fatal liver failure (FLF), the cutoff value of PLFEI was switched to −1.97 whose sensitivity and specificity were 100% and 68.8%, respectively. PLFEI will be a more comprehensive, sensitive, and accurate index assessing perioperative LRF in liver cancer patients who receive liver resection. And keeping PLFEI <−1.97 is a safety margin for preventing FLF in PLC patients who underwent liver resection. PMID:25929924

  1. A comprehensive method for predicting fatal liver failure of patients with liver cancer resection.

    PubMed

    Li, Jiangfa; Lei, Biao; Nie, Xingju; Lin, Linku; Tahir, Syed Abdul; Shi, Wuxiang; Jin, Junfei; He, Songqing

    2015-05-01

    There are many methods to assess liver function, but none of them has been verified as fully effective. The purpose of this study is to establish a comprehensive method evaluating perioperative liver reserve function (LRF) in patients with primary liver cancer (PLC).In this study, 310 PLC patients who underwent liver resection were included. The cohort was divided into a training set (n = 235) and a validation set (n = 75). The factors affecting postoperative liver dysfunction (POLD) during preoperative, intraoperative, and postoperative periods were confirmed by logistic regression analysis. The equation for calculating the preoperative liver functional evaluation index (PLFEI) was established; the cutoff value of PLFEI determined through analysis by receiver-operating characteristic curve was used to predict postoperative liver function.The data showed that body mass index, international normalized ratio, indocyanine green (ICG) retention rate at 15 minutes (ICGR15), ICG elimination rate, standard remnant liver volume (SRLV), operative bleeding volume (OBV), blood transfusion volume, and operative time were statistically different (all P < 0.05) between 2 groups of patients with and without POLD. The relationship among PLFEI, ICGR15, OBV, and SRLV is expressed as an equation of "PLFEI = 0.181 × ICGR15 + 0.001 × OBV - 0.008 × SRLV." The cutoff value of PLFEI to predict POLD was -2.16 whose sensitivity and specificity were 90.3% and 73.5%, respectively. However, when predicting fatal liver failure (FLF), the cutoff value of PLFEI was switched to -1.97 whose sensitivity and specificity were 100% and 68.8%, respectively.PLFEI will be a more comprehensive, sensitive, and accurate index assessing perioperative LRF in liver cancer patients who receive liver resection. And keeping PLFEI <-1.97 is a safety margin for preventing FLF in PLC patients who underwent liver resection.

  2. Systemic inflammatory response and serum lipopolysaccharide levels predict multiple organ failure and death in alcoholic hepatitis.

    PubMed

    Michelena, Javier; Altamirano, José; Abraldes, Juan G; Affò, Silvia; Morales-Ibanez, Oriol; Sancho-Bru, Pau; Dominguez, Marlene; García-Pagán, Juan Carlos; Fernández, Javier; Arroyo, Vicente; Ginès, Pere; Louvet, Alexandre; Mathurin, Philippe; Mehal, Wajahat Z; Caballería, Juan; Bataller, Ramón

    2015-09-01

    Alcoholic hepatitis (AH) frequently progresses to multiple organ failure (MOF) and death. However, the driving factors are largely unknown. At admission, patients with AH often show criteria of systemic inflammatory response syndrome (SIRS) even in the absence of an infection. We hypothesize that the presence of SIRS may predispose to MOF and death. To test this hypothesis, we studied a cohort including 162 patients with biopsy-proven AH. The presence of SIRS and infections was assessed in all patients, and multivariate analyses identified variables independently associated with MOF and 90-day mortality. At admission, 32 (19.8%) patients were diagnosed with a bacterial infection, while 75 (46.3%) fulfilled SIRS criteria; 58 patients (35.8%) developed MOF during hospitalization. Short-term mortality was significantly higher among patients who developed MOF (62.1% versus 3.8%, P < 0.001). The presence of SIRS was a major predictor of MOF (odds ratio = 2.69, P = 0.025) and strongly correlated with mortality. Importantly, the course of patients with SIRS with and without infection was similar in terms of MOF development and short-term mortality. Finally, we sought to identify serum markers that differentiate SIRS with and without infection. We studied serum levels of high-sensitivity C-reactive protein, procalcitonin, and lipopolysaccharide at admission. All of them predicted mortality. Procalcitonin, but not high-sensitivity C-reactive protein, serum levels identified those patients with SIRS and infection. Lipopolysaccharide serum levels predicted MOF and the response to prednisolone. In the presence or absence of infections, SIRS is a major determinant of MOF and mortality in AH, and the mechanisms involved in the development of SIRS should be investigated; procalcitonin serum levels can help to identify patients with infection, and lipopolysaccharide levels may help to predict mortality and the response to steroids. © 2015 by the American Association

  3. Systemic Inflammatory Response and Serum Lipopolysaccharide Levels Predict Multiple Organ Failure and Death in Alcoholic Hepatitis

    PubMed Central

    Michelena, Javier; Altamirano, José; Abraldes, Juan G.; Affò, Silvia; Morales-Ibanez, Oriol; Sancho-Bru, Pau; Dominguez, Marlene; García-Pagán, Juan Carlos; Fernández, Javier; Arroyo, Vicente; Ginès, Pere; Louvet, Alexandre; Mathurin, Philippe; Mehal, Wajahat Z.; Caballería, Juan; Bataller, Ramón

    2015-01-01

    Alcoholic hepatitis (AH) frequently progresses to multiple organ failure (MOF) and death. However, the driving factors are largely unknown. At admission, patients with AH often show criteria of systemic inflammatory response syndrome (SIRS) even in the absence of an infection. We hypothesize that the presence of SIRS may predispose to MOF and death. To test this hypothesis, we studied a cohort including 162 patients with biopsy-proven AH. The presence of SIRS and infections was assessed in all patients, and multivariate analyses identified variables independently associated with MOF and 90-day mortality. At admission, 32 (19.8%) patients were diagnosed with a bacterial infection, while 75 (46.3%) fulfilled SIRS criteria; 58 patients (35.8%) developed MOF during hospitalization. Short-term mortality was significantly higher among patients who developed MOF (62.1% versus 3.8%, P <0.001). The presence of SIRS was a major predictor of MOF (odds ratio = 2.69, P=0.025) and strongly correlated with mortality. Importantly, the course of patients with SIRS with and without infection was similar in terms of MOF development and short-term mortality. Finally, we sought to identify serum markers that differentiate SIRS with and without infection. We studied serum levels of high-sensitivity C-reactive protein, procalcitonin, and lipopolysaccharide at admission. All of them predicted mortality. Procalcitonin, but not high-sensitivity C-reactive protein, serum levels identified those patients with SIRS and infection. Lipopolysaccharide serum levels predicted MOF and the response to prednisolone. Conclusion In the presence or absence of infections, SIRS is a major determinant of MOF and mortality in AH, and the mechanisms involved in the development of SIRS should be investigated; procalcitonin serum levels can help to identify patients with infection, and lipopolysaccharide levels may help to predict mortality and the response to steroids. PMID:25761863

  4. Application of support vector machine for prediction of medication adherence in heart failure patients.

    PubMed

    Son, Youn-Jung; Kim, Hong-Gee; Kim, Eung-Hee; Choi, Sangsup; Lee, Soo-Kyoung

    2010-12-01

    Heart failure (HF) is a progressive syndrome that marks the end-stage of heart diseases, and it has a high mortality rate and significant cost burden. In particular, non-adherence of medication in HF patients may result in serious consequences such as hospital readmission and death. This study aims to identify predictors of medication adherence in HF patients. In this work, we applied a Support Vector Machine (SVM), a machine-learning method useful for data classification. Data about medication adherence were collected from patients at a university hospital through self-reported questionnaire. The data included 11 variables of 76 patients with HF. Mathematical simulations were conducted in order to develop a SVM model for the identification of variables that would best predict medication adherence. To evaluate the robustness of the estimates made with the SVM models, leave-one-out cross-validation (LOOCV) was conducted on the data set. THE TWO MODELS THAT BEST CLASSIFIED MEDICATION ADHERENCE IN THE HF PATIENTS WERE: one with five predictors (gender, daily frequency of medication, medication knowledge, New York Heart Association [NYHA] functional class, spouse) and the other with seven predictors (age, education, monthly income, ejection fraction, Mini-Mental Status Examination-Korean [MMSE-K], medication knowledge, NYHA functional class). The highest detection accuracy was 77.63%. SVM modeling is a promising classification approach for predicting medication adherence in HF patients. This predictive model helps stratify the patients so that evidence-based decisions can be made and patients managed appropriately. Further, this approach should be further explored in other complex diseases using other common variables.

  5. Serum microRNA expression patterns that predict early treatment failure in prostate cancer patients

    PubMed Central

    Singh, Prashant K.; Preus, Leah; Hu, Qiang; Yan, Li; Long, Mark D.; Morrison, Carl D.; Nesline, Mary; Johnson, Candace S.; Koochekpour, Shahriar; Kohli, Manish; Liu, Song; Trump, Donald L.

    2014-01-01

    We aimed to identify microRNA (miRNA) expression patterns in the serum of prostate cancer (CaP) patients that predict the risk of early treatment failure following radical prostatectomy (RP). Microarray and Q-RT-PCR analyses identified 43 miRNAs as differentiating disease stages within 14 prostate cell lines and reflectedpublically available patient data. 34 of these miRNA were detectable in the serum of CaP patients. Association with time to biochemical progression was examined in a cohort of CaP patients following RP. A greater than two-fold increase in hazard of biochemical progression associated with altered expression of miR-103, miR-125b and miR-222 (p <.0008) in the serum of CaP patients. Prediction models based on penalized regression analyses showed that the levels of the miRNAs and PSA together were better at detecting false positives than models without miRNAs, for similar level of sensitivity. Analyses of publically available data revealed significant and reciprocal relationships between changes in CpG methylation and miRNA expression patterns suggesting a role for CpG methylation to regulate miRNA. Exploratory validation supported roles for miR-222 and miR-125b to predict progression risk in CaP. The current study established that expression patterns of serum-detectable miRNAs taken at the time of RP are prognostic for men who are at risk of experiencing subsequent early biochemical progression. These non-invasive approaches could be used to augment treatment decisions. PMID:24583788

  6. Peak Exercise Oxygen Uptake Predicts Recurrent Admissions in Heart Failure With Preserved Ejection Fraction.

    PubMed

    Palau, Patricia; Domínguez, Eloy; Núñez, Eduardo; Ramón, José María; López, Laura; Melero, Joana; Sanchis, Juan; Bellver, Alejandro; Santas, Enrique; Bayes-Genis, Antoni; Chorro, Francisco J; Núñez, Julio

    2017-06-27

    Heart failure with preserved ejection fraction (HFpEF) is a highly prevalent syndrome with an elevated risk of morbidity and mortality. To date, there is scarce evidence on the role of peak exercise oxygen uptake (peak VO2) for predicting the morbidity burden in HFpEF. We sought to evaluate the association between peak VO2 and the risk of recurrent hospitalizations in patients with HFpEF. A total of 74 stable symptomatic patients with HFpEF underwent a cardiopulmonary exercise test between June 2012 and May 2016. A negative binomial regression method was used to determine the association between the percentage of predicted peak VO2 (pp-peak VO2) and recurrent hospitalizations. Risk estimates are reported as incidence rate ratios. The mean age was 72.5 ± 9.1 years, 53% were women, and all patients were in New York Heart Association functional class II to III. Mean peak VO2 and median pp-peak VO2 were 10 ± 2.8mL/min/kg and 60% (range, 47-67), respectively. During a median follow-up of 276 days [interquartile range, 153-1231], 84 all-cause hospitalizations in 31 patients (41.9%) were registered. A total of 15 (20.3%) deaths were also recorded. On multivariate analysis, accounting for mortality as a terminal event, pp-peak VO2 was independently and linearly associated with the risk of recurrent admission. Thus, and modeled as continuous, a 10% decrease of pp-peak VO2 increased the risk of recurrent hospitalizations by 32% (IRR, 1.32; 95%CI, 1.03-1.68; P = .028). In symptomatic elderly patients with HFpEF, pp-peak VO2 predicts all-cause recurrent admission. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  7. Prediction factors for failure to seek treatment following traumatic dental injuries to primary teeth.

    PubMed

    Firmino, Ramon Targino; Siqueira, Maria Betânia Lins Dantas; Vieira-Andrade, Raquel Gonçalves; Gomes, Genara Brum; Martins, Carolina Castro; Paiva, Saul Martins; Granville-Garcia, Ana Flávia

    2014-01-01

    The objective of this study was to evaluate prediction factors for failure to seek treatment following a traumatic dental injury (TDI) to primary teeth among preschool children in the city of Campina Grande, Brazil. A cross-sectional study was carried out involving 277 children 3 to 5 years of age, with TDI, enrolled in public and private preschools. Parents filled out a form addressing demographic data and whether or not they had sought treatment. Clinical examinations were performed by three dentists who had undergone a calibration exercise (Kappa: 0.85 to 0.90) for the evaluation of TDI. Bivariate and multivariate Poisson regression models were constructed (α=5%). Enamel fracture was the most prevalent type of TDI (48.7%) and the upper central incisors were the most affected teeth (88.4%). The frequency of seeking dental treatment was low (9.7%). The following variables were associated with failure to seek treatment following TDI: a household income greater than one minimum wage (PR=1.170; 95%CI 1.018-1.341), parents/caregivers' perception of a child's oral health as poor (PR=1.100; 95%CI 1.026-1.176), and the non-perception of TDI by parents/caregivers (PR=1.250; 95%CI 1.142-1.360). In the present study, the frequency of seeking treatment following TDI was low, and parents/caregivers with a higher income, a poor perception of their child's oral health and a lack of awareness regarding the trauma were more likely to fail to seek treatment following TDI to primary teeth.

  8. Risk factors predictive of right ventricular failure after left ventricular assist device implantation.

    PubMed

    Drakos, Stavros G; Janicki, Lindsay; Horne, Benjamin D; Kfoury, Abdallah G; Reid, Bruce B; Clayson, Stephen; Horton, Kenneth; Haddad, Francois; Li, Dean Y; Renlund, Dale G; Fisher, Patrick W

    2010-04-01

    Right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation appears to be associated with increased mortality. However, the determination of which patients are at greater risk of developing postoperative RVF remains controversial and relatively unknown. We sought to determine the preoperative risk factors for the development of RVF after LVAD implantation. The data were obtained for 175 consecutive patients who had received an LVAD. RVF was defined by the need for inhaled nitric oxide for >/=48 hours or intravenous inotropes for >14 days and/or right ventricular assist device implantation. An RVF risk score was developed from the beta coefficients of the independent variables from a multivariate logistic regression model predicting RVF. Destination therapy (DT) was identified as the indication for LVAD implantation in 42% of our patients. RVF after LVAD occurred in 44% of patients (n = 77). The mortality rates for patients with RVF were significantly greater at 30, 180, and 365 days after implantation compared to patients with no RVF. By multivariate logistic regression analysis, 3 preoperative factors were significantly associated with RVF after LVAD implantation: (1) a preoperative need for intra-aortic balloon counterpulsation, (2) increased pulmonary vascular resistance, and (3) DT. The developed RVF risk score effectively stratified the risk of RV failure and death after LVAD implantation. In conclusion, given the progressively growing need for DT, the developed RVF risk score, derived from a population with a large percentage of DT patients, might lead to improved patient selection and help stratify patients who could potentially benefit from early right ventricular assist device implantation. Copyright 2010 Elsevier Inc. All rights reserved.

  9. Urinary cadmium levels predict mortality of patients with acute heart failure

    PubMed Central

    Hsu, Ching-Wei; Weng, Cheng-Hao; Lee, Cheng-Chia; Lin-Tan, Dan-Tzu; Chu, Pao-Hsien; Chen, Kuan-Hsing; Yen, Tzung-Hai; Huang, Wen-Hung

    2017-01-01

    Background Acute heart failure (AHF) is a serious condition that is associated with increased mortality in critically ill patients. Previous studies indicated that environmental exposure to cadmium increases mortality of general populations. However, the relationship of cadmium exposure and mortality is unclear for AHF patients. Materials and methods A total of 153 patients with AHF in intensive care units (ICUs) met the inclusion criteria and were followed up for 6 months. Demographic data, AHF etiology, hematological and biochemical data, and hospital mortality were recorded. The scores of two predictive systems (Sequential Organ Failure Assessment [SOFA], Acute Physiology and Chronic Health Evaluation II [APACHE II]) for mortality in critically ill patients were calculated, and urinary cadmium levels were recorded. Results At the end of the follow-up period, the mortality rate was 24.8%. The survivors (n=115) had higher urinary cadmium levels on day 1 (D1UCd) of ICU admission than non-survivors (n=38). A multiple linear regression analysis revealed a positive correlation between D1UCd and acute kidney injury, but a negative correlation between D1UCd and the level of serum albumin. A multivariate Cox analysis indicated that D1UCd was an independent predictor of mortality in AHF patients. For each increment of 1 μg of D1UCd, the hazard ratio for ICU mortality was 1.20 (95% confidence interval [CI]: 1.09–1.32, P<0.001). The area under the receiver operating characteristic curve for D1UCd was 0.84 (95% CI: 0.78–0.91), better than the values for the SOFA and APACHE II systems. Conclusion The D1UCd may serve as a single predictor of hospital mortality for AHF patients in the ICU. Because of the high mortality and smaller sample size, more investigations are required to confirm these observations and elucidate the underlying mechanisms. PMID:28392700

  10. Systolic Strain Abnormalities to Predict Hospital Readmission in Patients With Heart Failure and Normal Ejection Fraction

    PubMed Central

    Borer, Steven M.; Kokkirala, Aravind; O'Sullivan, David M.; Silverman, David I.

    2011-01-01

    Background Despite intensive investigation, the pathogenesis of heart failure with normal ejection fraction (HFNEF) remains unclear. We hypothesized that subtle abnormalities of systolic function might play a role, and that abnormal systolic strain and strain rate would provide a marker for adverse outcomes. Methods Patients of new CHF and left ventricular ejection fraction > 50% were included. Exclusion criteria were recent myocardial infarction, severe valvular heart disease, severe left ventricular hypertrophy (septum >1.8 cm), or a technically insufficient echocardiogram. Average peak systolic strain and strain rate were measured using an off-line grey scale imaging technique. Systolic strain and strain rate for readmitted patients were compared with those who remained readmission-free. Results One hundred consecutive patients with a 1st admission for HFNEF from January 1, 2004 through December 31, 2007, inclusive, were analyzed. Fifty two patients were readmitted with a primary diagnosis of heart failure. Systolic strain and strain rates were reduced in both study groups compared to controls. However, systolic strain did not differ significantly between the two groups (-11.7% for those readmitted compared with -12.9% for those free from readmission, P = 0.198) and systolic strain rates also were similar (-1.05 s-1 versus -1.09 s-1, P = 0.545). E/e’ was significantly higher in readmitted patients compared with those who remained free from readmission (14.5 versus 11.0, P = 0.013). E/e’ (OR 1.189, 95% CI 1.026-1.378; P = 0.021) was found to be an independent predictor for HFNEF readmission. Conclusions Among patients with new onset HFNEF, SS and SR rates are reduced compared with patients free of HFNEF, but do not predict hospital readmission. Elevated E/e’ is a predictor of readmission in these patients.

  11. Both high and low HbA1c predict incident heart failure in type 2 diabetes mellitus.

    PubMed

    Parry, Helen M; Deshmukh, Harshal; Levin, Daniel; Van Zuydam, Natalie; Elder, Douglas H J; Morris, Andrew D; Struthers, Allan D; Palmer, Colin N A; Doney, Alex S F; Lang, Chim C

    2015-03-01

    Type 2 diabetes mellitus is an independent risk factor for heart failure development, but the relationship between incident heart failure and antecedent glycemia has not been evaluated. The Genetics of Diabetes Audit and Research in Tayside Study study holds data for 8683 individuals with type 2 diabetes mellitus. Dispensed prescribing, hospital admission data, and echocardiography reports were linked to extract incident heart failure cases from December 1998 to August 2011. All available HbA1c measures until heart failure development or end of study were used to model HbA1c time-dependently. Individuals were observed from study enrolment until heart failure development or end of study. Proportional hazard regression calculated heart failure development risk associated with specific HbA1c ranges accounting for comorbidities associated with heart failure, including blood pressure, body mass index, and coronary artery disease. Seven hundred and one individuals with type 2 diabetes mellitus (8%) developed heart failure during follow up (mean 5.5 years, ±2.8 years). Time-updated analysis with longitudinal HbA1c showed that both HbA1c <6% (hazard ratio =1.60; 95% confidence interval, 1.38-1.86; P value <0.0001) and HbA1c >10% (hazard ratio =1.80; 95% confidence interval, 1.60-2.16; P value <0.0001) were independently associated with the risk of heart failure. Both high and low HbA1c predicted heart failure development in our cohort, forming a U-shaped relationship. © 2015 American Heart Association, Inc.

  12. Differential subsidence and its effect on subsurface infrastructure: predicting probability of pipeline failure (STOOP project)

    NASA Astrophysics Data System (ADS)

    de Bruijn, Renée; Dabekaussen, Willem; Hijma, Marc; Wiersma, Ane; Abspoel-Bukman, Linda; Boeije, Remco; Courage, Wim; van der Geest, Johan; Hamburg, Marc; Harmsma, Edwin; Helmholt, Kristian; van den Heuvel, Frank; Kruse, Henk; Langius, Erik; Lazovik, Elena

    2017-04-01

    Due to heterogeneity of the subsurface in the delta environment of the Netherlands, differential subsidence over short distances results in tension and subsequent wear of subsurface infrastructure, such as water and gas pipelines. Due to uncertainties in the build-up of the subsurface, however, it is unknown where this problem is the most prominent. This is a problem for asset managers deciding when a pipeline needs replacement: damaged pipelines endanger security of supply and pose a significant threat to safety, yet premature replacement raises needless expenses. In both cases, costs - financial or other - are high. Therefore, an interdisciplinary research team of geotechnicians, geologists and Big Data engineers from research institutes TNO, Deltares and SkyGeo developed a stochastic model to predict differential subsidence and the probability of consequent pipeline failure on a (sub-)street level. In this project pipeline data from company databases is combined with a stochastic geological model and information on (historical) groundwater levels and overburden material. Probability of pipeline failure is modelled by a coupling with a subsidence model and two separate models on pipeline behaviour under stress, using a probabilistic approach. The total length of pipelines (approx. 200.000 km operational in the Netherlands) and the complexity of the model chain that is needed to calculate a chance of failure, results in large computational challenges, as it requires massive evaluation of possible scenarios to reach the required level of confidence. To cope with this, a scalable computational infrastructure has been developed, composing a model workflow in which components have a heterogeneous technological basis. Three pilot areas covering an urban, a rural and a mixed environment, characterised by different groundwater-management strategies and different overburden histories, are used to evaluate the differences in subsidence and uncertainties that come with

  13. Changes in the epidemiology and prediction of multiple-organ failure after injury.

    PubMed

    Dewar, David C; Tarrant, Seth M; King, Kate L; Balogh, Zsolt J

    2013-03-01

    The epidemiology of multiple-organ failure (MOF) after injury has been changing, questioning the validity of previously described prediction models. This study aimed to describe the current epidemiology of MOF. The secondary aim was development of a prediction model that could be used for early identification of patients at risk of MOF. A 60-month prospective epidemiologic study was undertaken at an Australian Level I trauma center. Data were collected on trauma patients that met inclusion criteria (intensive care unit [ICU] admission; Injury Severity Score [ISS] > 15; age > 18 years, head Abbreviated Injury Scale [AIS] score < 3; and survival for >48 hours). Demographics, injury severity (ISS), physiologic parameters, MOF status based on the Denver score, and outcome data were prospectively collected. Univariate analysis and multivariate logistic modeling were performed; p < 0.05 was considered significant. Data are presented as percentage or mean (SD). A total of 140 patients met the inclusion criteria (age, 47 [21] years; ISS, 30 [11]; male, 69%), 21 patients (15%) developed MOF, and MOF associated mortality was 24% versus non-MOF mortality rate of 3%. Patients who developed MOF had longer ICU stays (19 [7] vs. 7 [5], p < 0.01) and had more ventilator days (18 [9] vs. 4 [4], p < 0.01). Prediction models were generated at two time points as follows: admission and 24 hours after injury. At admission, age (>65 years) and admission platelet count (<150 × 10(9)/L) were significant predictors of MOF; at 24 hours after injury, MOF was predicted by age more than 65 years, admission platelet count less than 150 × 10(9)/L, maximum creatinine of greater than 150 × 10(9)/L and minimum bilirubin of greater than 10 × 10(9)/L. Shock parameters and injury severity did not predict MOF. The incidence of MOF (15%) is lower than reported 15 years ago; MOF remains a major cause of ICU resource use and late mortality after injury. The independent predictors of MOF have

  14. Mild cognitive impairment predicts death and readmission within 30days of discharge for heart failure.

    PubMed

    Huynh, Quan L; Negishi, Kazuaki; Blizzard, Leigh; Saito, Makoto; De Pasquale, Carmine G; Hare, James L; Leung, Dominic; Stanton, Tony; Sanderson, Kristy; Venn, Alison J; Marwick, Thomas H

    2016-10-15

    Cognitive impairment is highly prevalent in heart failure (HF), and may be associated with short-term readmission. This study investigated the role of cognition, incremental to other clinical and non-clinical factors, independent of depression and anxiety, in predicting 30-day readmission or death in HF. This study followed 565 patients from an Australia-wide HF longitudinal study. Cognitive function (MoCA score) together with standard clinical and non-clinical factors, mental health and 2D echocardiograms were collected before hospital discharge. The study outcomes were death and readmission within 30days of discharge. Logistic regression, Harrell's C-statistic, integrated discrimination improvement (IDI) and net reclassification index were used for analysis. Among 565 patients, 255 (45%) had at least mild cognitive impairment (MoCA≤22). Death (n=43, 8%) and readmission (n=122, 21%) within 30days of discharge were more likely to occur among patients with mild cognitive impairment (OR=2.00, p=0.001). MoCA score was also negatively associated with 30-day readmission or death (OR=0.91, p<0.001) independent of other risk factors. Adding MoCA score to an existing prediction model of 30-day readmission significantly improved discrimination (C-statistic=0.715 vs. 0.617, IDI estimate 0.077, p<0.001). From prediction models developed from our study, adding MoCA score (C-statistic=0.83) provided incremental value to that of standard clinical and non-clinical factors (C-statistic=0.76) and echocardiogram parameters (C-statistic=0.81) in predicting 30-day readmission or death. Reclassification analysis suggests that addition of MoCA score improved classification for a net of 12% of patients with 30-day readmission or death and of 6% of patients without (p=0.002). Mild cognitive impairment predicts short-term outcomes in HF, independent of clinical and non-clinical factors. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. A Statistical Approach to Predict the Failure Enthalpy and Reliability of Irradiated PWR Fuel Rods During Reactivity-Initiated Accidents

    SciTech Connect

    Nam, Cheol; Jeong, Yong-Hwan; Jung, Youn-Ho

    2001-11-15

    During the last decade, the failure behavior of high-burnup fuel rods under a reactivity-initiated accident (RIA) condition has been a serious concern since fuel rod failures at low enthalpy have been observed. This has resulted in the reassessment of existing licensing criteria and failure-mode study. To address the issue, a statistics-based methodology is suggested to predict failure probability of irradiated fuel rods under an RIA. Based on RIA simulation results in the literature, a failure enthalpy correlation for an irradiated fuel rod is constructed as a function of oxide thickness, fuel burnup, and pulse width. Using the failure enthalpy correlation, a new concept of ''equivalent enthalpy'' is introduced to reflect the effects of the three primary factors as well as peak fuel enthalpy into a single damage parameter. Moreover, the failure distribution function with equivalent enthalpy is derived, applying a two-parameter Weibull statistical model. Finally, the sensitivity analysis is carried out to estimate the effects of burnup, corrosion, peak fuel enthalpy, pulse width, and cladding materials used.

  16. Trend recognition and failure prediction of the attitude determination and control system of the Space Station Freedom

    NASA Astrophysics Data System (ADS)

    Nelson, Kyle S.; Hadden, George D.

    An approach to automated trend recognition and failure prediction in the health parameter data of spacecraft is described. The approach, State-Based Feature Recognition (SBER), combines intelligent data filtering with state machines to detect the presence of features (trends and impending failures) in the health parameter data of spacecraft. SBFR, when implemented in a space-based or ground-based monitoring system, can increase spacecraft autonomy and decrease technician workload. An implemented, prototype Space Station Freedom (SSF) Maintenance and Diagnostic System (SSFMDS) that demonstrates the applicability of SBFR to trend detection and failure prediction will be described. SBFR allows features to be tracked, using specialized state machines, as they develop in a time-independent manner, allowing both short term and long term features to be detected. Each state machine operates independently of the other machines, making simultaneous feature tracking possible.

  17. Implicit and Explicit Attitudes Predict Smoking Cessation: Moderating Effects of Experienced Failure to Control Smoking and Plans to Quit

    PubMed Central

    Chassin, Laurie; Presson, Clark C.; Sherman, Steven J.; Seo, Dong-Chul; Macy, Jon

    2010-01-01

    The current study tested implicit and explicit attitudes as prospective predictors of smoking cessation in a Midwestern community sample of smokers. Results showed that the effects of attitudes significantly varied with levels of experienced failure to control smoking and plans to quit. Explicit attitudes significantly predicted later cessation among those with low (but not high or average) levels of experienced failure to control smoking. Conversely, however, implicit attitudes significantly predicted later cessation among those with high levels of experienced failure to control smoking, but only if they had a plan to quit. Because smoking cessation involves both controlled and automatic processes, interventions may need to consider attitude change interventions that focus on both implicit and explicit attitudes. PMID:21198227

  18. Novel Nomogram That Predicts Aggressive Disease and Treatment Failure Among African-American Men with Prostate Cancer

    DTIC Science & Technology

    2015-12-01

    AWARD NUMBER: W81XWH-13-1-0474 TITLE: Novel Nomogram That Predicts Aggressive Disease and Treatment Failure Among African-American Men with...2015 2. REPORT TYPE Final 3. DATES COVERED 30 Sep 2013 - 29 Sep 2015 4. TITLE AND SUBTITLE Novel Nomogram That Predicts Aggressive Disease and Treatment...patterns, and behavior. More recent data suggest that genetic/biologic factors may at least in part contribute to more aggressive disease in AA men

  19. The value of cough peak flow measurements in the assessment of extubation or decannulation readiness.

    PubMed

    Winck, J C; LeBlanc, C; Soto, J L; Plano, F

    2015-01-01

    Insufficient cough strength has a major role in extubation and decannulation outcomes. Cough capacity can be easily evaluated by measuring flows during coughing. Values vary depending on whether cough flows are measured through the mouth or through a tracheostomy or endotracheal tube. It is important to standardize these measurements and start using them routinely in the extubation and decannulation processes. Values of cough peak flow >160 L/min measured at the mouth or a value of cough PEF >60 L/min measured at the endotracheal tube suggest successful decannulation or extubation. Copyright © 2014 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.

  20. Pitfalls and Precautions When Using Predicted Failure Data for Quantitative Analysis of Safety Risk for Human Rated Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Hatfield, Glen S.; Hark, Frank; Stott, James

    2016-01-01

    Launch vehicle reliability analysis is largely dependent upon using predicted failure rates from data sources such as MIL-HDBK-217F. Reliability prediction methodologies based on component data do not take into account risks attributable to manufacturing, assembly, and process controls. These sources often dominate component level reliability or risk of failure probability. While consequences of failure is often understood in assessing risk, using predicted values in a risk model to estimate the probability of occurrence will likely underestimate the risk. Managers and decision makers often use the probability of occurrence in determining whether to accept the risk or require a design modification. Due to the absence of system level test and operational data inherent in aerospace applications, the actual risk threshold for acceptance may not be appropriately characterized for decision making purposes. This paper will establish a method and approach to identify the pitfalls and precautions of accepting risk based solely upon predicted failure data. This approach will provide a set of guidelines that may be useful to arrive at a more realistic quantification of risk prior to acceptance by a program.

  1. A comparative study of slope failure prediction using logistic regression, support vector machine and least square support vector machine models

    NASA Astrophysics Data System (ADS)

    Zhou, Lim Yi; Shan, Fam Pei; Shimizu, Kunio; Imoto, Tomoaki; Lateh, Habibah; Peng, Koay Swee

    2017-08-01

    A comparative study of logistic regression, support vector machine (SVM) and least square support vector machine (LSSVM) models has been done to predict the slope failure (landslide) along East-West Highway (Gerik-Jeli). The effects of two monsoon seasons (southwest and northeast) that occur in Malaysia are considered in this study. Two related factors of occurrence of slope failure are included in this study: rainfall and underground water. For each method, two predictive models are constructed, namely SOUTHWEST and NORTHEAST models. Based on the results obtained from logistic regression models, two factors (rainfall and underground water level) contribute to the occurrence of slope failure. The accuracies of the three statistical models for two monsoon seasons are verified by using Relative Operating Characteristics curves. The validation results showed that all models produced prediction of high accuracy. For the results of SVM and LSSVM, the models using RBF kernel showed better prediction compared to the models using linear kernel. The comparative results showed that, for SOUTHWEST models, three statistical models have relatively similar performance. For NORTHEAST models, logistic regression has the best predictive efficiency whereas the SVM model has the second best predictive efficiency.

  2. Predicting hospitalization and mortality in patients with heart failure: The BARDICHE-index.

    PubMed

    Uszko-Lencer, Nicole H M K; Frankenstein, Lutz; Spruit, Martijn A; Maeder, Micha T; Gutmann, Marc; Muzzarelli, Stefano; Osswald, Stefan; Pfisterer, Matthias E; Zugck, Christian; Brunner-La Rocca, Hans-Peter

    2017-01-15

    Prediction of events in chronic heart failure (CHF) patients is still difficult and available scores are often complex to calculate. Therefore, we developed and validated a simple-to-use, multidimensional prognostic index for such patients. A theoretical model was developed based on known prognostic factors of CHF that are easily obtainable: Body mass index (B), Age (A), Resting systolic blood pressure (R), Dyspnea (D), N-termInal pro brain natriuretic peptide (NT-proBNP) (I), Cockroft-Gault equation to estimate glomerular filtration rate (C), resting Heart rate (H), and Exercise performance using the 6-min walk test (E) (the BARDICHE-index). Scores were given for all components and added, the sum ranging from 1 (lowest value) to 25 points (maximal value), with estimated risk being highest in patients with highest scores. Scores were categorized into three groups: a low (≤8 points); medium (9-16 points), or high (>16 points) BARDICHE-score. The model was validated in a data set of 1811 patients from two prospective CHF-cohorts (median follow-up 887days). The primary outcome was 5-year all-cause survival. Secondary outcomes were 5-year survival without all-cause hospitalization and 5-year survival without CHF-related hospitalization. There were significant differences between BARDICHE-risk groups for mortality (hazard ratio=3.63 per BARDICHE-group, 95%-CI 3.10-4.25), mortality or all-cause hospitalization (HR=2.00 per BARDICHE-group, 95%-CI 1.83-2.19), and mortality or CHF-related hospitalization (HR=3.43 per BARDICHE-group, 95%-CI 3.01-3.92; all P<10-50). Outcome was predicted independently of left ventricular ejection fraction (LVEF) and gender. The BARDICHE-index is a simple multidimensional prognostic tool for patients with CHF, independently of LVEF. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. DNA Methylation-Guided Prediction of Clinical Failure in High-Risk Prostate Cancer

    PubMed Central

    Joniau, Steven; Lerut, Evelyne; Laenen, Annouschka; Gevaert, Thomas; Gevaert, Olivier; Spahn, Martin; Kneitz, Burkhard; Gramme, Pierre; Helleputte, Thibault; Isebaert, Sofie; Haustermans, Karin; Bollen, Mathieu

    2015-01-01

    Background Prostate cancer (PCa) is a very heterogeneous disease with respect to clinical outcome. This study explored differential DNA methylation in a priori selected genes to diagnose PCa and predict clinical failure (CF) in high-risk patients. Methods A quantitative multiplex, methylation-specific PCR assay was developed to assess promoter methylation of the APC, CCND2, GSTP1, PTGS2 and RARB genes in formalin-fixed, paraffin-embedded tissue samples from 42 patients with benign prostatic hyperplasia and radical prostatectomy specimens of patients with high-risk PCa, encompassing training and validation cohorts of 147 and 71 patients, respectively. Log-rank tests, univariate and multivariate Cox models were used to investigate the prognostic value of the DNA methylation. Results Hypermethylation of APC, CCND2, GSTP1, PTGS2 and RARB was highly cancer-specific. However, only GSTP1 methylation was significantly associated with CF in both independent high-risk PCa cohorts. Importantly, trichotomization into low, moderate and high GSTP1 methylation level subgroups was highly predictive for CF. Patients with either a low or high GSTP1 methylation level, as compared to the moderate methylation groups, were at a higher risk for CF in both the training (Hazard ratio [HR], 3.65; 95% CI, 1.65 to 8.07) and validation sets (HR, 4.27; 95% CI, 1.03 to 17.72) as well as in the combined cohort (HR, 2.74; 95% CI, 1.42 to 5.27) in multivariate analysis. Conclusions Classification of primary high-risk tumors into three subtypes based on DNA methylation can be combined with clinico-pathological parameters for a more informative risk-stratification of these PCa patients. PMID:26086362

  4. DNA Methylation-Guided Prediction of Clinical Failure in High-Risk Prostate Cancer.

    PubMed

    Litovkin, Kirill; Van Eynde, Aleyde; Joniau, Steven; Lerut, Evelyne; Laenen, Annouschka; Gevaert, Thomas; Gevaert, Olivier; Spahn, Martin; Kneitz, Burkhard; Gramme, Pierre; Helleputte, Thibault; Isebaert, Sofie; Haustermans, Karin; Bollen, Mathieu

    2015-01-01

    Prostate cancer (PCa) is a very heterogeneous disease with respect to clinical outcome. This study explored differential DNA methylation in a priori selected genes to diagnose PCa and predict clinical failure (CF) in high-risk patients. A quantitative multiplex, methylation-specific PCR assay was developed to assess promoter methylation of the APC, CCND2, GSTP1, PTGS2 and RARB genes in formalin-fixed, paraffin-embedded tissue samples from 42 patients with benign prostatic hyperplasia and radical prostatectomy specimens of patients with high-risk PCa, encompassing training and validation cohorts of 147 and 71 patients, respectively. Log-rank tests, univariate and multivariate Cox models were used to investigate the prognostic value of the DNA methylation. Hypermethylation of APC, CCND2, GSTP1, PTGS2 and RARB was highly cancer-specific. However, only GSTP1 methylation was significantly associated with CF in both independent high-risk PCa cohorts. Importantly, trichotomization into low, moderate and high GSTP1 methylation level subgroups was highly predictive for CF. Patients with either a low or high GSTP1 methylation level, as compared to the moderate methylation groups, were at a higher risk for CF in both the training (Hazard ratio [HR], 3.65; 95% CI, 1.65 to 8.07) and validation sets (HR, 4.27; 95% CI, 1.03 to 17.72) as well as in the combined cohort (HR, 2.74; 95% CI, 1.42 to 5.27) in multivariate analysis. Classification of primary high-risk tumors into three subtypes based on DNA methylation can be combined with clinico-pathological parameters for a more informative risk-stratification of these PCa patients.

  5. Transient elastography and aspartate aminotransferase to platelet ratio predict liver injury in paediatric intestinal failure.

    PubMed

    Hukkinen, Maria; Kivisaari, Reetta; Lohi, Jouko; Heikkilä, Päivi; Mutanen, Annika; Merras-Salmio, Laura; Pakarinen, Mikko P

    2016-03-01

    We aimed to evaluate the value of AST to platelet ratio (APRI) and transient elastography (TE) as predictors of liver histopathology in children with intestinal failure (IF). Altogether 93 liver biopsies from 57 children with parenteral nutrition (PN) duration ≥3 months were analysed. APRI measurement and TE (n = 46) were performed at the time of biopsy. IF was caused by short bowel syndrome in 75% of patients. At the time of liver biopsy, PN dependent patients (n = 42) were younger with longer PN duration compared to those weaned off PN (n = 51) (2.2 vs. 7.6 years, P < 0.001; 26 vs. 10.5 months, P = 0.043). Elevated transaminase or bilirubin levels were found in 51%, splenomegaly in 26%, and oesophageal varices in 3.5%. Histological fibrosis was present in 61% (Metavir stage F1; 27%, F2; 26%, F3-4; 9%), cholestasis in 25% and steatosis in 22% of biopsy specimens. TE was superior to APRI in prediction of any liver histopathology (fibrosis, cholestasis or steatosis) with areas under the receiving operating curve (AUROC) of 0.86 (95% CI 0.74-0.97) and 0.67 (95% CI 0.58-0.78) respectively. For prediction of ≥F1 and ≥F2 fibrosis, AUROC values for TE were 0.78 (95% CI 0.64-0.93) and 0.73 (95% CI 0.59-0.88), whereas APRI did not correlate with fibrosis stages. For detection of histological cholestasis, the AUROC for APRI was 0.77 (95% CI 0.64-0.89). Both TE and APRI are promising noninvasive methods for monitoring the development of IF-related liver histopathology. TE values reflected the degree of fibrosis better while APRI detected histological cholestasis more accurately. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Inpatient Unit Heart Failure Discharge Volume Predicts All-cause 30-Day Hospital Readmission.

    PubMed

    Dordunoo, Dzifa; Thomas, Sue A; Friedmann, Erika; Russell, Stuart D; Newhouse, Robin P; Akintade, Bim

    All-cause 30-day hospital readmission is a heart failure (HF) quality of care metric. Readmission costs the healthcare system $30.7 million annually. Specific structure, process, or patient factors that predispose patients to readmission are unclear. The aim of this study is to determine whether the addition of unit-level structural factors (attending medical service, patient-to-nurse ratio, and unit HF volume) predicts readmission beyond patient factors. A retrospective chart review of 425 patients who resided in Maryland and were discharged home in 2011 with the primary diagnosis of HF from a large, urban academic center was conducted. The patients were predominately (66.6%) black/African American, with mean (SD) age of 62.2 (14.8) years. Men represented 48.2% of the sample; 32% had nonischemic HF, 31.3% had preserved ejection fractions, 25.4% had implantable cardioverter defibrillators, and 15.3% had permanent pacemakers. Average length of stay was 6.0 days. All-cause 30-day hospital readmission rate was 20.2%. Inpatient unit HF discharge volume significantly predicted readmission after controlling for patient factors. The study found that discharge from inpatient units with higher HF discharge volume was associated with increased risk of readmission. The findings suggest that in caring for patients with severe HF, inpatient unit HF discharge volume may negatively impact care processes, increasing the odds of hospital readmission. It is unclear what specific care processes are responsible. The discharge period is a vulnerable point in care transition that warrants further investigation.

  7. Usefulness of Serum Triiodothyronine (T3) to Predict Outcomes in Patients Hospitalized With Acute Heart Failure.

    PubMed

    Rothberger, Gary D; Gadhvi, Sonya; Michelakis, Nickolaos; Kumar, Amit; Calixte, Rose; Shapiro, Lawrence E

    2017-02-15

    Thyroid hormone plays an important role in cardiac function. Low levels of serum triiodothyronine (T3) due to nonthyroidal illness syndrome may have adverse effects in heart failure (HF). This study was designed to assess the ability of T3 to predict in-hospital outcomes in patients with acute HF. In total, 137 patients without thyroid disease or treatment with drugs which affect TH levels, who were hospitalized with acute HF were prospectively enrolled and studied. TH levels were tested upon hospital admission, and outcomes were compared between patients with low (<2.3 pg/ml) and normal (≥2.3 pg/ml) free T3 levels as well as between those with low (<0.6 ng/ml) and normal (≥0.6 ng/ml) total T3 levels. Low free T3 correlated with an increased length of stay in the hospital (median 11 vs 7 days, p <0.001) and higher rates of intensive care unit admission (31.8% vs 16.9%, p = 0.047), with a trend toward increased need for invasive mechanical ventilation (9.0% vs 1.4%, p = 0.056). Low total T3 correlated with an increased length of stay in the hospital (median 11 vs 7 days, p <0.001) and increased need for invasive mechanical ventilation (9.8% vs 1.3%, p = 0.045). In conclusion, low T3 predicts worse hospital outcomes in patients with acute HF and can be useful in the risk stratification of these patients.

  8. GenSo-EWS: a novel neural-fuzzy based early warning system for predicting bank failures.

    PubMed

    Tung, W L; Quek, C; Cheng, P

    2004-05-01

    Bank failure prediction is an important issue for the regulators of the banking industries. The collapse and failure of a bank could trigger an adverse financial repercussion and generate negative impacts such as a massive bail out cost for the failing bank and loss of confidence from the investors and depositors. Very often, bank failures are due to financial distress. Hence, it is desirable to have an early warning system (EWS) that identifies potential bank failure or high-risk banks through the traits of financial distress. Various traditional statistical models have been employed to study bank failures [J Finance 1 (1975) 21; J Banking Finance 1 (1977) 249; J Banking Finance 10 (1986) 511; J Banking Finance 19 (1995) 1073]. However, these models do not have the capability to identify the characteristics of financial distress and thus function as black boxes. This paper proposes the use of a new neural fuzzy system [Foundations of neuro-fuzzy systems, 1997], namely the Generic Self-organising Fuzzy Neural Network (GenSoFNN) [IEEE Trans Neural Networks 13 (2002c) 1075] based on the compositional rule of inference (CRI) [Commun ACM 37 (1975) 77], as an alternative to predict banking failure. The CRI based GenSoFNN neural fuzzy network, henceforth denoted as GenSoFNN-CRI(S), functions as an EWS and is able to identify the inherent traits of financial distress based on financial covariates (features) derived from publicly available financial statements. The interaction between the selected features is captured in the form of highly intuitive IF-THEN fuzzy rules. Such easily comprehensible rules provide insights into the possible characteristics of financial distress and form the knowledge base for a highly desired EWS that aids bank regulation. The performance of the GenSoFNN-CRI(S) network is subsequently benchmarked against that of the Cox's proportional hazards model [J Banking Finance 10 (1986) 511; J Banking Finance 19 (1995) 1073], the multi

  9. Prediction of the Chemoreflex Gain by Common Clinical Variables in Heart Failure

    PubMed Central

    Mirizzi, Gianluca; Giannoni, Alberto; Ripoli, Andrea; Iudice, Giovanni; Bramanti, Francesca; Emdin, Michele; Passino, Claudio

    2016-01-01

    Background Peripheral and central chemoreflex sensitivity, assessed by the hypoxic or hypercapnic ventilatory response (HVR and HCVR, respectively), is enhanced in heart failure (HF) patients, is involved in the pathophysiology of the disease, and is under investigation as a potential therapeutic target. Chemoreflex sensitivity assessment is however demanding and, therefore, not easily applicable in the clinical setting. We aimed at evaluating whether common clinical variables, broadly obtained by routine clinical and instrumental evaluation, could predict increased HVR and HCVR. Methods and results 191 patients with systolic HF (left ventricular ejection fraction—LVEF—<50%) underwent chemoreflex assessment by rebreathing technique to assess HVR and HCVR. All patients underwent clinical and neurohormonal evaluation, comprising: echocardiogram, cardiopulmonary exercise test (CPET), daytime cardiorespiratory monitoring for breathing pattern evaluation. Regarding HVR, multivariate penalized logistic regression, Bayesian Model Averaging (BMA) logistic regression and random forest analysis identified, as predictors, the presence of periodic breathing and increased slope of the relation between ventilation and carbon dioxide production (VE/VCO2) during exercise. Again, the above-mentioned statistical tools identified as HCVR predictors plasma levels of N-terminal fragment of proBNP and VE/VCO2 slope. Conclusions In HF patients, the simple assessment of breathing pattern, alongside with ventilatory efficiency during exercise and natriuretic peptides levels identifies a subset of patients presenting with increased chemoreflex sensitivity to either hypoxia or hypercapnia. PMID:27099934

  10. Humidity sensor failure: a problem that should not be neglected by the numerical weather prediction community

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Tang, N.

    2014-07-01

    In this paper, a new issue that very low relative humidity observations exist in a deeper atmosphere layer in the low- and mid-troposphere is studied on the basis of the global radiosonde observations from December 2008 to November 2009, and the humidity retrieval productions from Formosa Satellite mission-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC, referred to as COSMIC hereafter) in the same period. Results show that these extremely dry relative humidity observations are considerable universal in the worldwide operational radiosonde data. Globally, the annual average occurrence probability of the extremely dry relative humidity is of 4.2%. These measurements usually occur between 20° and 40° latitudes in both Northern and Southern Hemispheres, and in the height from 700 to 450 hPa in the low- and mid-troposphere. Winter and spring are the favoured seasons for these extremely dry humidity observations, with the maximum ratio of 9.53% in the Northern Hemisphere and 16.82% in the Southern Hemisphere. The phenomenon is mainly related to the performance of the radiosonde humidity sensor and the cloud types traversed by the radiosonde balloon. These extremely low relative humidity observations are erroneous, which cannot represent the real atmospheric status, and are likely caused by the failure of humidity sensor. However, these observations have been archived as the formal data. It will affect the reliability of numerical weather prediction, the analysis of weather and climate, if the quality control procedure is not applied.

  11. Failure location prediction by finite element analysis for an additive manufactured mandible implant.

    PubMed

    Huo, Jinxing; Dérand, Per; Rännar, Lars-Erik; Hirsch, Jan-Michaél; Gamstedt, E Kristofer

    2015-09-01

    In order to reconstruct a patient with a bone defect in the mandible, a porous scaffold attached to a plate, both in a titanium alloy, was designed and manufactured using additive manufacturing. Regrettably, the implant fractured in vivo several months after surgery. The aim of this study was to investigate the failure of the implant and show a way of predicting the mechanical properties of the implant before surgery. All computed tomography data of the patient were preprocessed to remove metallic artefacts with metal deletion technique before mandible geometry reconstruction. The three-dimensional geometry of the patient's mandible was also reconstructed, and the implant was fixed to the bone model with screws in Mimics medical imaging software. A finite element model was established from the assembly of the mandible and the implant to study stresses developed during mastication. The stress distribution in the load-bearing plate was computed, and the location of main stress concentration in the plate was determined. Comparison between the fracture region and the location of the stress concentration shows that finite element analysis could serve as a tool for optimizing the design of mandible implants. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  12. Circulating long non-coding RNAs NRON and MHRT as novel predictive biomarkers of heart failure.

    PubMed

    Xuan, Lina; Sun, Lihua; Zhang, Ying; Huang, Yuechao; Hou, Yan; Li, Qingqi; Guo, Ying; Feng, Bingbing; Cui, Lina; Wang, Xiaoxue; Wang, Zhiguo; Tian, Ye; Yu, Bo; Wang, Shu; Xu, Chaoqian; Zhang, Mingyu; Du, Zhimin; Lu, Yanjie; Yang, Bao Feng

    2017-03-14

    This study sought to evaluate the potential of circulating long non-coding RNAs (lncRNAs) as biomarkers for heart failure (HF). We measured the circulating levels of 13 individual lncRNAs which are known to be relevant to cardiovascular disease in the plasma samples from 72 HF patients and 60 non-HF control participants using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) methods. We found that out of the 13 lncRNAs tested, non-coding repressor of NFAT (NRON) and myosin heavy-chain-associated RNA transcripts (MHRT) had significantly higher plasma levels in HF than in non-HF subjects: 3.17 ± 0.30 versus 1.0 ± 0.07 for NRON (P < 0.0001) and 1.66 ± 0.14 versus 1.0 ± 0.12 for MHRT (P < 0.0001). The area under the ROC curve was 0.865 for NRON and 0.702 for MHRT. Univariate and multivariate analyses identified NRON and MHRT as independent predictors for HF. Spearman's rank correlation analysis showed that NRON was negatively correlated with HDL and positively correlated with LDH, whereas MHRT was positively correlated with AST and LDH. Hence, elevation of circulating NRON and MHRT predicts HF and may be considered as novel biomarkers of HF.

  13. Decreases in Daily Physical Activity Predict Acute Decline in Attention/Executive Function in Heart Failure

    PubMed Central

    Alosco, Michael L.; Spitznagel, Mary Beth; Cohen, Ronald; Sweet, Lawrence H.; Hayes, Scott M.; Josephson, Richard; Hughes, Joel; Gunstad, John

    2015-01-01

    Background Reduced physical activity (PA) may be one factor that contributes to cognitive decline and dementia in heart failure (HF). Yet, the longitudinal relationship between PA and cognition in HF is poorly understood due to limitations of past work, including single time assessments of PA. This is the first study to examine changes in objectively measured PA and cognition over time in HF. Methods At baseline and 12-weeks, 57 HF patients completed psychosocial self-report measures, a neuropsychological battery, and wore an accelerometer for seven days. Results At baseline, HF patients spent an average of 597.83 (SD = 75.91) minutes per day sedentary. Steps per day declined from baseline to the 12-week follow-up; there was also a trend for declines in moderate-vigorous PA. Regression analyses controlling for sex, HF severity, and depressive symptoms showed that decreases in light (p = 0.08) and moderate-vigorous (p = 0.04) daily PA emerged as strong predictors of declines in attention/executive function over the 12-week period, but not memory or language. Conclusions Reductions in daily PA predicted acute decline in attention/executive function in HF, but not memory or language. Modifications to daily PA may attenuate cognitive decline and prospective studies are needed to test this possibility. PMID:25573830

  14. Predicting time-to-failure in rock extrapolated from secondary creep

    NASA Astrophysics Data System (ADS)

    Hao, Sheng-Wang; Zhang, Bao-Ju; Tian, Ji-Feng; Elsworth, Derek

    2014-03-01

    Stress relaxation experiments are reported that culminate in energetic failure in rocks analogous to the loading cycle and subsequent localization or reactivation on brittle faults embedded in an elastic medium. Universally, rapid primary deformation arrests and transitions into a long secondary deformation phase that ultimately accelerates to catastrophic rupture. Primary deformation (u) conforms to Andrade's law as du/dt ~ (tc - t0)θ with a standard exponent of 2/3. In the long, and readily observable, secondary phase, the samples both deform and analogously shed load near linearly in time. This stress relaxation rate exhibits a robust power law dependency with time-to-rupture and exhibits the same 2/3 power law exponent observed in the primary phase. Similarly, the brittle strain energy released in the tertiary collapse scales with a normalized secondary stress relaxation rate. Together, these observations suggest a way to predict both the timing of rupture and its energetics from the observed stress (or strain) rate during the secondary relaxation stage.

  15. TBCs for Gas Turbines under Thermomechanical Loadings: Failure Behaviour and Life Prediction

    NASA Astrophysics Data System (ADS)

    Beck, T.; Trunova, O.; Herzog, R.; Singheiser, L.

    2012-10-01

    The present contribution gives an overview about recent research on a thermal barrier coating (TBC) system consisted of (i) an intermetallic MCrAlY-alloy Bondcoat (BC) applied by vacuum plasma spraying (VPS) and (ii) an Yttria Stabilised Zirconia (YSZ) top coat air plasma sprayed (APS) at Forschungszentrum Juelich, Institute of Energy and Climate Research (IEK-1). The influence of high temperature dwell time, maximum and minimum temperature on crack growth kinetics during thermal cycling of such plasma sprayed TBCs is investigated using infrared pulse thermography (IT), acoustic emission (AE) analysis and scanning electron microscopy. Thermocyclic life in terms of accumulated time at maximum temperature decreases with increasing high temperature dwell time and increases with increasing minimum temperature. AE analysis proves that crack growth mainly occurs during cooling at temperatures below the ductile-to-brittle transition temperature of the BC. Superimposed mechanical load cycles accelerate delamination crack growth and, in case of sufficiently high mechanical loadings, result in premature fatigue failure of the substrate. A life prediction model based on TGO growth kinetics and a fracture mechanics approach has been developed which accounts for the influence of maximum and minimum temperature as well as of high temperature dwell time with good accuracy in an extremely wide parameter range.

  16. Chest physiotherapy for preventing morbidity in babies being extubated from mechanical ventilation.

    PubMed

    Flenady, V J; Gray, P H

    2002-01-01

    Chest physiotherapy has been used to clear secretions and help lung ventilation in newborns who have needed mechanical ventilation for respiratory problems. However concerns about the safety of some forms of chest physiotherapy have been expressed. To assess the effects of active chest physiotherapy on babies being extubated from mechanical ventilation for neonatal respiratory failure. The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of electronic databases: Oxford Database of Perinatal Trials; Cochrane Controlled Trials Register (Cochrane Library Issue 4 2001); MEDLINE (1966-2001); and CINAHL (1982-2001), previous reviews including cross references, abstracts, conferences, symposia proceedings, expert informants and journal hand searching mainly in the English language. All trials utilising random or quasi-random patient allocation, in which active chest physiotherapy was compared with non-active techniques (eg positioning and suction alone) or no intervention in the periextubation period. Assessment of methodological quality and extraction of data for each included trial was undertaken independently by the authors. Data were extracted for the primary outcomes of postextubation lobar collapse, use of reintubation, duration of oxygen therapy, intracranial haemorrhage, cerebral cystic lesions, long term neurosensory impairment and death. Subgroup analysis was performed on different treatment frequencies and gestational age less than 32 weeks. Meta-analysis was conducted using a fixed effects model. Results are presented as relative risk (RR), risk difference (RD) and number needed to treat (NNT) for categorical data and mean difference (MD) for data measured on a continuous scale. All outcomes are reported with the use of 95% confidence intervals. In this review of four trials, two of which were carried out 15 & 23 years ago, no clear benefit of periextubation active chest physiotherapy can be seen. Active chest

  17. Lamivudine Concentration in Hair and Prediction of Virologic Failure and Drug Resistance among HIV Patients Receiving Free ART in China

    PubMed Central

    Wang, Zhe; Wu, Jianjun; Zhang, Jiafeng; Ruan, Yuhua; Hsi, Jenny; Liao, Lingjie; Shao, Yiming; Xing, Hui

    2016-01-01

    Background The assessment of adherence to antiretroviral therapy (ART) is important in order to predict treatment outcomes. Lamivudine (3TC) is one of the most widely used NRTIs in China, but its concentrations in hair and association with virologic failure and drug resistance have not been studied. Methods We conducted a cross-sectional survey to investigate 3TC concentrations in hair as a predictor of virologic failure and drug resistance among HIV patients receiving free ART. We also compared the capacity of hair 3TC concentrations with self-reported adherence in predicting virologic responses. Hair 3TC concentrations were detected through the LC-MS/MS system. Results In patients without HIV drug resistance (HIVDR), with a threshold hair 3TC concentration of 260 ng/g, the sensitivity and specificity in predicting virologic suppression were 76.9% and 89.9%, respectively. Some factors, including CD4+ cell counts, initial treatment regimens with 3TC, and current regimens with second-line drugs, influenced the association between hair 3TC concentrations and virologic suppression. In patients who experienced virologic failure with HIVDR, with a threshold of 180 ng/g, the sensitivity and specificity were 70.0% and 74.4%, respectively. Hair 3TC concentrations had higher sensitivity and specificity in predicting virologic failure and drug resistance than self-reported adherence. Conclusions The hair 3TC concentration was a stronger indicator than self-reported adherence in predicting virologic failure and drug resistance in HIV patients receiving free ART. PMID:27119346

  18. Better Adherence to Treatment Recommendations in Heart Failure Predicts Improved Cognitive Function at a One Year Follow Up

    PubMed Central

    Alosco, Michael L.; Spitznagel, Mary Beth; Cohen, Ronald; Sweet, Lawrence H.; Josephson, Richard; Hughes, Joel; Rosneck, Jim; Gunstad, John

    2016-01-01

    Introduction Treatment non-adherence is common in heart failure and associated with poor health outcomes in this population. Recent cross-sectional work in heart failure and past work in other medical populations suggests cognitive function is a key determinant of patient’s ability to adhere to treatment recommendations. However, it is also possible that treatment adherence is an important modifier and predictor of cognitive function, though no study has examined this possibility and we sought to do so in a sample of heart failure patients. Methods 115 patients with heart failure self-reported adherence to treatment recommendations. The Modified Mini Mental State Examination (3MS), Trail Making Test parts A and B, and the California Verbal Learning Test-II (CVLT-II) assessed cognitive function. These procedures were performed at baseline and a 12-month follow-up. Results Global cognition and memory abilities improved over the 12-month period. Regression analyses controlling for baseline and medical and demographic factors showed better baseline treatment adherence predicted improved 12-month performances on the 3MS and CVLT-II. Adherence to medication and diet regimens and smoking abstinence emerged as the most important contributors. Conclusions Better treatment adherence predicted improved cognition one-year later in HF. Prospective studies that utilize objective assessments of treatment adherence are needed to confirm our findings and examine whether improved treatment adherence preserves cognitive function in heart failure. PMID:25352233

  19. Better adherence to treatment recommendations in heart failure predicts improved cognitive function at a one-year follow-up.

    PubMed

    Alosco, Michael L; Spitznagel, Mary Beth; Cohen, Ronald; Sweet, Lawrence H; Josephson, Richard; Hughes, Joel; Rosneck, Jim; Gunstad, John

    2014-01-01

    Treatment nonadherence is common in heart failure (HF) and is associated with poor health outcomes in this population. Recent cross-sectional work in heart failure and past work in other medical populations suggest that cognitive function is a key determinant of a patient's ability to adhere to treatment recommendations. However, it is also possible that treatment adherence is an important modifier and predictor of cognitive function, though no study has examined this possibility, and we sought to do so in a sample of heart failure patients. A total of 115 patients with heart failure self-reported adherence to treatment recommendations. The Modified Mini Mental State Examination (3MS), Trail Making Test Parts A and B, and the California Verbal Learning Test-II (CVLT-II) assessed cognitive function. These procedures were performed at baseline and a 12-month follow-up. Global cognition and memory abilities improved over the 12-month period. Regression analyses controlling for baseline and medical and demographic factors showed that better baseline treatment adherence predicted improved 12-month performances on the 3MS and CVLT-II. Adherence to medication and diet regimens and smoking abstinence emerged as the most important contributors. Better treatment adherence predicted improved cognition one year later in HF. Prospective studies that utilize objective assessments of treatment adherence are needed to confirm our findings and examine whether improved treatment adherence preserves cognitive function in heart failure.

  20. Use of Risk Models to Predict Death in the Next Year Among Individual Ambulatory Patients With Heart Failure.

    PubMed

    Allen, Larry A; Matlock, Daniel D; Shetterly, Susan M; Xu, Stanley; Levy, Wayne C; Portalupi, Laura B; McIlvennan, Colleen K; Gurwitz, Jerry H; Johnson, Eric S; Smith, David H; Magid, David J

    2017-04-01

    The clinical practice guidelines for heart failure recommend the use of validated risk models to estimate prognosis. Understanding how well models identify individuals who will die in the next year informs decision making for advanced treatments and hospice. To quantify how risk models calculated in routine practice estimate more than 50% 1-year mortality among ambulatory patients with heart failure who die in the subsequent year. Ambulatory adults with heart failure from 3 integrated health systems were enrolled between 2005 and 2008. The probability of death was estimated using the Seattle Heart Failure Model (SHFM) and the Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) risk calculator. Baseline covariates were collected from electronic health records. Missing covariates were imputed. Estimated mortality was compared with actual mortality at both population and individual levels. One-year mortality. Among 10 930 patients with heart failure, the median age was 77 years, and 48.0% of these patients were female. In the year after study enrollment, 1661 patients died (15.9% by life-table analysis). At the population level, 1-year predicted mortality among the cohort was 9.7% for the SHFM (C statistic of 0.66) and 17.5% for the MAGGIC risk calculator (C statistic of 0.69). At the individual level, the SHFM predicted a more than 50% probability of dying in the next year for 8 of the 1661 patients who died (sensitivity for 1-year death was 0.5%) and for 5 patients who lived at least a year (positive predictive value, 61.5%). The MAGGIC risk calculator predicted a more than 50% probability of dying in the next year for 52 of the 1661 patients who died (sensitivity, 3.1%) and for 63 patients who lived at least a year (positive predictive value, 45.2%). Conversely, the SHFM estimated that 8496 patients (77.8%) had a less than 15% probability of dying at 1 year, yet this lower-risk end of the score range captured nearly two-thirds of deaths (n = 997

  1. [Unplanned extubation in ICU, and the relevance of non-dependent patient variables the quality of care].

    PubMed

    González-Castro, A; Peñasco, Y; Blanco, C; González-Fernández, C; Domínguez, M J; Rodríguez-Borregán, J C

    2014-01-01

    To evaluate, for a consecutive year, the magnitude of unplanned extubation, looking for non-dependent patient variables. Prospective, observational study of cases and controls in a mixed intensive care unit within in a tertiary hospital. Patients were considered cases with more than 24 hours who had an episode of unplanned extubation. Prospective collection of variables case as time of unplanned extubation (collection time), identification of the box where the patient was admitted, presence and type of physical restraint, development of ventilator-associated pneumonia (VAP) and death. There were 17 unplanned extubation in 15 patients, 1.21 unplanned extubation per 100 days of MV. The unplanned extubation had an inhomogeneous spatial distribution (number of boxes). The time distribution of cases compared with controls showed significant differences in time distribution (P=.02). The comparative analysis between cases and controls, showed increased mortality, increased length of ICU stay, longer hospital stay and increased risk for VAP when patients suffer an episode of unplanned extubation. Unplanned extubation occurs most frequently in a given time slot of the day, may play a role in the spatial location of the patient; occurs most often in patients who are in the process of weaning from mechanical ventilation, and develop greater VAP. Copyright © 2014 SECA. Published by Elsevier Espana. All rights reserved.

  2. Pulmonary Vascular Distensibility Predicts Pulmonary Hypertension Severity, Exercise Capacity, and Survival in Heart Failure

    PubMed Central

    Malhotra, Rajeev; Dhakal, Bishnu P.; Eisman, Aaron S.; Pappagianopoulos, Paul P.; Dress, Ashley; Weiner, Rory B.; Baggish, Aaron L.; Semigran, Marc J.; Lewis, Gregory D.

    2016-01-01

    Background Pulmonary vascular (PV) distensibility, defined as the percent increase in pulmonary vessel diameter per mmHg increase in pressure, permits the pulmonary arteries to increase in size to accommodate increased blood flow. We hypothesized that PV distensibility is abnormally low in patients with heart failure (HF) and serves as an important determinant of right ventricular performance and exercise capacity. Methods and Results Patients with HF and preserved ejection fraction (HFpEF, n=48), HF and reduced ejection fraction (HFrEF, n=55), pulmonary hypertension without left-heart failure (PAH, n=18), and control subjects (n=30) underwent cardiopulmonary exercise testing with invasive hemodynamic monitoring and first-pass radionuclide ventriculography. PV distensibility was derived from 1257 matched measurements (mean±SD, 8±2 per subject) of PA pressure, PA wedge pressure and cardiac output. PV distensibility was lowest in the PAH group (0.40±0.24% per mmHg) and intermediate in the HFpEF and HFrEF groups (0.92±0.39 and 0.84±0.33% per mmHg, respectively) compared to the control group (1.39±0.32% per mmHg, P<0.0001 for all three). PV distensibility was associated with change in RVEF (ρ=0.39, P<0.0001) with exercise and was an independent predictor of peak VO2. PV distensibility also predicted cardiovascular mortality independent of peak VO2 in HF patients (n=103, Cox HR 0.30, 95% CI 0.10–0.93, P=0.036). In a subset of HFrEF patients (n=26), 12 weeks of treatment with the pulmonary vasodilator sildenafil or placebo led to a 24.6% increase in PV distensibility (P=0.015) in the sildenafil group only. Conclusions PV distensibility is reduced in patients with HF and PAH and is closely related to RV systolic function during exercise, maximal exercise capacity, and survival. Furthermore, PV distensibility is modifiable with selective pulmonary vasodilator therapy and may represent an important target for therapy in selected HF patients with pulmonary

  3. Implementation of Predictive Data Mining Techniques for Identifying Risk Factors of Early AVF Failure in Hemodialysis Patients

    PubMed Central

    Rezapour, Mohammad; Khavanin Zadeh, Morteza; Sepehri, Mohammad Mehdi

    2013-01-01

    Arteriovenous fistula (AVF) is an important vascular access for hemodialysis (HD) treatment but has 20–60% rate of early failure. Detecting association between patient's parameters and early AVF failure is important for reducing its prevalence and relevant costs. Also predicting incidence of this complication in new patients is a beneficial controlling procedure. Patient safety and preservation of early AVF failure is the ultimate goal. Our research society is Hasheminejad Kidney Center (HKC) of Tehran, which is one of Iran's largest renal hospitals. We analyzed data of 193 HD patients using supervised techniques of data mining approach. There were 137 male (70.98%) and 56 female (29.02%) patients introduced into this study. The average of age for all the patients was 53.87 ± 17.47 years. Twenty eight patients had smoked and the number of diabetic patients and nondiabetics was 87 and 106, respectively. A significant relationship was found between “diabetes mellitus,” “smoking,” and “hypertension” with early AVF failure in this study. We have found that these mentioned risk factors have important roles in outcome of vascular surgery, versus other parameters such as “age.” Then we predicted this complication in future AVF surgeries and evaluated our designed prediction methods with accuracy rates of 61.66%–75.13%. PMID:23861725

  4. Serum Procalcitonin and Peripheral Venous Lactate for Predicting Dengue Shock and/or Organ Failure: A Prospective Observational Study

    PubMed Central

    Thanachartwet, Vipa; Desakorn, Varunee; Sahassananda, Duangjai; Jittmittraphap, Akanitt; Oer-areemitr, Nittha; Osothsomboon, Sathaporn; Surabotsophon, Manoon; Wattanathum, Anan

    2016-01-01

    Background Currently, there are no biomarkers that can predict the incidence of dengue shock and/or organ failure, although the early identification of risk factors is important in determining appropriate management to reduce mortality. Therefore, we sought to determine the factors associated with dengue shock and/or organ failure and to evaluate the prognostic value of serum procalcitonin (PCT) and peripheral venous lactate (PVL) levels as biomarkers of dengue shock and/or organ failure. Methodology/Principal Findings A prospective observational study was conducted among adults hospitalized for confirmed viral dengue infection at the Hospital for Tropical Diseases in Bangkok, Thailand between October 2013 and July 2015. Data, including baseline characteristics, clinical parameters, laboratory findings, serum PCT and PVL levels, management, and outcomes, were recorded on pre-defined case report forms. Of 160 patients with dengue, 128 (80.0%) patients had dengue without shock or organ failure, whereas 32 (20.0%) patients developed dengue with shock and/or organ failure. Using a stepwise multivariate logistic regression analysis, PCT ≥0.7 ng/mL (odds ratio [OR]: 4.80; 95% confidence interval [CI]: 1.60–14.45; p = 0.005) and PVL ≥2.5 mmol/L (OR: 27.99, 95% CI: 8.47–92.53; p <0.001) were independently associated with dengue shock and/or organ failure. A combination of PCT ≥0.7 ng/mL and PVL ≥2.5 mmol/L provided good prognostic value for predicting dengue shock and/or organ failure, with an area under the receiver operating characteristics curve of 0.83 (95% CI: 0.74–0.92), a sensitivity of 81.2% (95% CI: 63.6–92.8%), and a specificity of 84.4% (95% CI: 76.9–90.2%). Dengue shock patients with non-clearance of PCT and PVL expired during hospitalization. Conclusions/Significance PCT ≥0.7 ng/mL and PVL ≥2.5 mmol/L were independently associated with dengue shock and/or organ failure. The combination of PCT and PVL levels could be used as prognostic

  5. Sensitivity, Specificity, Predictive Values, and Accuracy of Three Diagnostic Tests to Predict Inferior Alveolar Nerve Blockade Failure in Symptomatic Irreversible Pulpitis.

    PubMed

    Chavarría-Bolaños, Daniel; Rodríguez-Wong, Laura; Noguera-González, Danny; Esparza-Villalpando, Vicente; Montero-Aguilar, Mauricio; Pozos-Guillén, Amaury

    2017-01-01

    The inferior alveolar nerve block (IANB) is the most common anesthetic technique used on mandibular teeth during root canal treatment. Its success in the presence of preoperative inflammation is still controversial. The aim of this study was to evaluate the sensitivity, specificity, predictive values, and accuracy of three diagnostic tests used to predict IANB failure in symptomatic irreversible pulpitis (SIP). A cross-sectional study was carried out on the mandibular molars of 53 patients with SIP. All patients received a single cartridge of mepivacaine 2% with 1 : 100000 epinephrine using the IANB technique. Three diagnostic clinical tests were performed to detect anesthetic failure. Anesthetic failure was defined as a positive painful response to any of the three tests. Sensitivity, specificity, predictive values, accuracy, and ROC curves were calculated and compared and significant differences were analyzed. IANB failure was determined in 71.7% of the patients. The sensitivity scores for the three tests (lip numbness, the cold stimuli test, and responsiveness during endodontic access) were 0.03, 0.35, and 0.55, respectively, and the specificity score was determined as 1 for all of the tests. Clinically, none of the evaluated tests demonstrated a high enough accuracy (0.30, 0.53, and 0.68 for lip numbness, the cold stimuli test, and responsiveness during endodontic access, resp.). A comparison of the areas under the curve in the ROC analyses showed statistically significant differences between the three tests (p < 0.05). None of the analyzed tests demonstrated a high enough accuracy to be considered a reliable diagnostic tool for the prediction of anesthetic failure.

  6. Sensitivity, Specificity, Predictive Values, and Accuracy of Three Diagnostic Tests to Predict Inferior Alveolar Nerve Blockade Failure in Symptomatic Irreversible Pulpitis

    PubMed Central

    Rodríguez-Wong, Laura; Noguera-González, Danny; Esparza-Villalpando, Vicente; Montero-Aguilar, Mauricio

    2017-01-01

    Introduction The inferior alveolar nerve block (IANB) is the most common anesthetic technique used on mandibular teeth during root canal treatment. Its success in the presence of preoperative inflammation is still controversial. The aim of this study was to evaluate the sensitivity, specificity, predictive values, and accuracy of three diagnostic tests used to predict IANB failure in symptomatic irreversible pulpitis (SIP). Methodology A cross-sectional study was carried out on the mandibular molars of 53 patients with SIP. All patients received a single cartridge of mepivacaine 2% with 1 : 100000 epinephrine using the IANB technique. Three diagnostic clinical tests were performed to detect anesthetic failure. Anesthetic failure was defined as a positive painful response to any of the three tests. Sensitivity, specificity, predictive values, accuracy, and ROC curves were calculated and compared and significant differences were analyzed. Results IANB failure was determined in 71.7% of the patients. The sensitivity scores for the three tests (lip numbness, the cold stimuli test, and responsiveness during endodontic access) were 0.03, 0.35, and 0.55, respectively, and the specificity score was determined as 1 for all of the tests. Clinically, none of the evaluated tests demonstrated a high enough accuracy (0.30, 0.53, and 0.68 for lip numbness, the cold stimuli test, and responsiveness during endodontic access, resp.). A comparison of the areas under the curve in the ROC analyses showed statistically significant differences between the three tests (p < 0.05). Conclusion None of the analyzed tests demonstrated a high enough accuracy to be considered a reliable diagnostic tool for the prediction of anesthetic failure. PMID:28694714

  7. Limits of Predictability of Cascading Overload Failures in Spatially-Embedded Networks with Distributed Flows.

    PubMed

    Moussawi, A; Derzsy, N; Lin, X; Szymanski, B K; Korniss, G

    2017-09-15

    Cascading failures are a critical vulnerability of complex information or infrastructure networks. Here we investigate the properties of load-based cascading failures in real and synthetic spatially-embedded network structures, and propose mitigation strategies to reduce the severity of damages caused by such failures. We introduce a stochastic method for optimal heterogeneous distribution of resources (node capacities) subject to a fixed total cost. Additionally, we design and compare the performance of networks with N-stable and (N-1)-stable network-capacity allocations by triggering cascades using various real-world node-attack and node-failure scenarios. We show that failure mitigation through increased node protection can be effectively achieved against single-node failures. However, mitigating against multiple node failures is much more difficult due to the combinatorial increase in possible sets of initially failing nodes. We analyze the robustness of the system with increasing protection, and find that a critical tolerance exists at which the system undergoes a phase transition, and above which the network almost completely survives an attack. Moreover, we show that cascade-size distributions measured in this region exhibit a power-law decay. Finally, we find a strong correlation between cascade sizes induced by individual nodes and sets of nodes. We also show that network topology alone is a weak predictor in determining the progression of cascading failures.

  8. Predicting treatment failure in patients with community acquired pneumonia: a case-control study

    PubMed Central

    2014-01-01

    Introduction Treatment failure in community-acquired-pneumonia (CAP) patients is associated with a high mortality rate, and therefore are a matter of great concern in clinical management. Those patients have increased mortality and are a target population for randomized clinical trials. Methods A case–control study was performed in patients with CAP (non-failure cases vs. failure cases, discriminating by late and early failure). CRP, PCT, interleukin 1, 6, 8 and 10 and TNF were determined at days 1 and 3 of hospitalization. Results A total of 253 patients were included in this study where 83 patients presented treatment failure. Of these, 40 (48.2%) had early failure. A discriminative effect was found for a higher CURB-65 score among late failure patients (p = 0.004). A significant increase on day 1 of hospitalization in CRP (p < 0.001), PCT (p = 0.004), IL-6 (p < 0.001) and IL-8 (p = 0.02), and a decrease in IL-1 (p = 0.06) in patients with failure was observed compared with patients without failure. On day 3, only the increase in CRP (p < 0.001), PCT (p = 0.007) and IL-6 (p < 0.001) remained significant. Independent predictors for early failure were higher IL-6 levels on day 1 (OR = 1.78, IC = 1.2-2.6) and pleural effusion (OR = 2.25, IC = 1.0-5.3), and for late failure, higher PCT levels on day 3 (OR = 1.60, IC = 1.0-2.5), CURB-65 score ≥ 3 (OR = 1.43, IC = 1.0-2.0), and multilobar involvement (OR = 4.50, IC = 2.1-9.9). Conclusions There was a good correlation of IL-6 levels and CAP failure and IL-6 & PCT with late CAP failure. Pleural effusion and multilobar involvement were simple clinical predictors of early and late failure, respectively. Trial registration IRB Register: http://2009/5451. PMID:24996572

  9. Functional outcome in chronic heart failure after exercise training: Possible predictive value of heart rate variability.

    PubMed

    Ricca-Mallada, Roberto; Migliaro, Edurado R; Silvera, Gabriela; Chiappella, Lilian; Frattini, Rossana; Ferrando-Castagnetto, Federico

    2017-04-01

    Controlled exercise training (ET) is a valuable therapeutic addition to pharmacological treatment in most patients with chronic heart failure (CHF), reducing long-term mortality, preventing cardiac remodelling and improving functional capacity. Despite the fact that the mechanism underlying its benefits might be multifactorial, a sustained improvement in autonomic balance is usually attributed as a major effect. Nevertheless, not all eligible subjects show the same response to ET, probably due to several differences in the subpopulations enrolled. We hypothesize that some heart rate variability (HRV) indexes could be valid tools to optimize the selection and follow-up of CHF patients receiving ET intervention. Forty patients with CHF and left ventricular ejection fraction (LVEF)≤40% under complete evidence-based pharmacological treatment were included; 20 were assigned to a program of controlled ET on a 3-times/week basis during 24 weeks, training group (TG) and 20 received a standard follow-up program, control group (CG). In each patient, full clinical assessments, echocardiography, HRV analysis and 6-minute-walk test were performed at the beginning and the end of the study. After 24 weeks, patients in the TG showed a significant improvement in LVEF, 6-minute walk test, functional class of symptoms and HRV parasympathetic related indices (HF and rMSSD). Patients in the CG did not exhibit any improvement in the aforementioned indices and experienced more adverse events. Moreover, an initial value of HF<150 ms(2)/Hz or rMSSD<20ms predicted better outcomes of the ET program, including improvements in systolic function, the distance walked in 6minutes, and the functional class of symptoms, along with a reduction in clinical events. In CHF patients, HRV indexes related to parasympathetic function are valid and clinically useful tools to select and follow-up those candidates that could experience superior functional improvement after ET. Copyright © 2016 Elsevier

  10. Elevated troponin T on discharge predicts poor outcome of decompensated heart failure.

    PubMed

    Koide, Kimi; Yoshikawa, Tsutomu; Nagatomo, Yuji; Kohsaka, Shun; Anzai, Toshihisa; Meguro, Tomomi; Ogawa, Satoshi

    2010-05-01

    Persistent elevation of cardiac troponin T (cTnT) predicts an adverse clinical outcome in patients with chronic heart failure (HF), but the underlying mechanisms remain to be determined. We investigated the association between predischarge cTnT elevation and coexistent pathophysiology in patients with decompensated HF. Plasma cTnT levels were determined before discharge in 170 patients with decompensated HF. We divided the patients into a group that was positive for cTnT [cTnT(+) group, n = 40] and a group that was negative for cTnT [cTnT(-) group, n = 130]. Multivariate analysis showed that use of beta-blocker therapy (odds ratio [OR] = 0.236, P = 0.003), an elevated high-sensitivity C-reactive protein (hsCRP) level (OR = 3.731, P = 0.006), a high brain natriuretic peptide (BNP) level (OR = 3.570, P = 0.007), diabetes (OR = 3.090, P = 0.018), and anemia (OR = 2.330, P = 0.047) were independently associated with cTnT positivity. During a mean follow-up period of 441 days after discharge, total mortality (P < 0.001), cardiac death (P < 0.001), and exacerbation of HF requiring hospitalization (P = 0.007) were all more common in the cTnT(+) group than in the cTnT(-) group. Cox proportional hazards analysis showed that cTnT positivity was an independent predictor of total mortality (hazard ratio = 5.008, P = 0.004) in an age- and gender-matched model. Elevation of cTnT during convalescence was associated with lack of beta-blocker therapy, a high hsCRP level at discharge, a high BNP level at discharge, diabetes, and anemia, and a worse clinical outcome in patients with decompensated HF.

  11. The Change in Body Weight During Hospitalization Predicts Mortality in Patients With Acute Decompensated Heart Failure

    PubMed Central

    Komaki, Tomo; Miura, Shin-ichiro; Arimura, Tadaaki; Shiga, Yuhei; Morii, Joji; Kuwano, Takashi; Imaizumi, Satoshi; Kitajima, Ken; Iwata, Atsushi; Morito, Natsumi; Yahiro, Eiji; Fujimi, Kanta; Matsunaga, Akira; Saku, Keijiro

    2017-01-01

    Background In our experience, the change in body weight (BW) during hospitalization varies greatly in patients with acute decompensated heart failure (HF). Since the clinical significance of a change in BW is not clear, we investigated whether a change in BW could predict mortality. Methods We retrospectively enrolled 130 patients (72 males; aged 68 ± 10 years) who were hospitalized due to acute decompensated HF and followed for 2 years after discharge. The change in the BW index during hospitalization (ΔBWI) was calculated as (BW at hospital admission minus BW at hospital discharge)/body surface area at hospital discharge. Results The patients were divided into quartiles according to ΔBWI, and the 2-year mortality rates in the quartiles with the lowest, second, third and highest ΔBWI were 18.8%, 12.1%, 3.1% and 9.1%, respectively. In a multivariate Cox proportional hazards analysis after adjusting for variables with a P value less than 0.05, ΔBWI was independently associated with 2-year mortality (P = 0.0002), and the quartile with the lowest ΔBWI had a higher relative risk (RR) for 2-year mortality than the quartile with the highest ΔBWI (RR: 7.46, 95% confidence interval: 1.03 - 53.99, P = 0.04). Conclusion In conclusion, ΔBWI was significantly associated with 2-year mortality after discharge, which indicates that ΔBWI might be a simple predictor of prognosis in acute decompensated HF. PMID:28179967

  12. A simple sarcopenia screening test predicts future adverse events in patients with heart failure.

    PubMed

    Onoue, Yoshiro; Izumiya, Yasuhiro; Hanatani, Shinsuke; Tanaka, Tomoko; Yamamura, Satoru; Kimura, Yuichi; Araki, Satoshi; Sakamoto, Kenji; Tsujita, Kenichi; Yamamoto, Eiichiro; Yamamuro, Megumi; Kojima, Sunao; Kaikita, Koichi; Hokimoto, Seiji

    2016-07-15

    Progressive loss of skeletal muscle termed "sarcopenia" is an independent risk factor for mortality in patients with cardiovascular diseases. A simple screening test that can identify sarcopenia using three variables (age, grip strength and calf circumference) was recently developed. We evaluated the clinical utility of this screening test in patients with heart failure (HF). HF patients were divided into the sarcopenia (n=82) and non-sarcopenia (n=37) groups based on the sarcopenia score. Circulating BNP and high-sensitive cardiac troponin T levels were significantly higher, and left ventricular ejection fraction was lower in the sarcopenia group than non-sarcopenia group. Kaplan-Meier curve showed that HF event-free survival rate was significantly lower in the sarcopenia group. Multivariate Cox proportional hazards analysis identified BNP (ln[BNP]) (hazard ratio [HR]: 1.58; 95% CI: 1.09-2.29, p=0.02), hs-CRP (ln[CRP]) (HR: 1.82; 95% CI: 1.23-2.68; p<0.01) and sarcopenia score (HR: 1.03; 95% CI: 1.01-1.05, p<0.01) as independent predictors of HF events. In receiver operating characteristic analysis, adding the sarcopenia score to BNP levels increased an area under the curve for future HF events (sarcopenia score alone, 0.77; BNP alone, 0.82; combination, 0.89). The sarcopenia screening test can be used to predict future adverse events in patients with HF. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Predicting Right Ventricular Failure in the Modern, Continuous Flow Left Ventricular Assist Device Era

    PubMed Central

    Atluri, Pavan; Goldstone, Andrew B.; Fairman, Alex S.; MacArthur, John W.; Shudo, Yasuhiro; Cohen, Jeffrey E.; Acker, Alexandra L.; Hiesinger, William; Howard, Jessica L.; Acker, Michael A.; Woo, Y. Joseph

    2014-01-01

    Background In the era of destination continuous flow left ventricular assist devices (LVAD), the decision of whether a patient will tolerate isolated LVAD support or will need biventricular support (BIVAD) can be challenging. Incorrect decision making with delayed right ventricular (RV) assist device implantation results in increased morbidity and mortality. Continuous flow LVADs have been shown to decrease pulmonary hyper-tension and improve RV function. We undertook this study to determine predictors in the continuous flow LVAD era that identify patients who are candidates for isolated LVAD therapy as opposed to biventricular support. Methods We reviewed demographic, hemodynamic, laboratory, and echocardiographic variables for 218 patients who underwent VAD implant from 2003 through 2011 (LVAD = 167, BIVAD = 51), during the era of continuous flow LVADs. Results Fifty preoperative risk factors were compared between patients who were successfully managed with an LVAD and those who required a BIVAD. Seventeen variables demonstrated statistical significance by univariate analysis. Multivariable logistic regression analysis identified central venous pressure >15 mmHg (OR 2.0, “C”), severe RV dysfunction (OR 3.7, “R”), preoperative intubation (OR 4.3, “I”), severe tricuspid regurgitation (OR 4.1, “T”), heart rate >100 (OR 2.0, Tachycardia - “T”) -CRITT as the major criteria predictive of the need for biventricular support. Utilizing these data, a highly sensitive and easy to use risk score for determining RV failure was generated that outperformed other established risk stratification tools. Conclusions We present a preoperative risk calculator to determine suitability of a patient for isolated LVAD support in the current continuous flow ventricular assist device era. PMID:23791165

  14. Quality of life predicts outcome in a heart failure disease management program.

    PubMed

    O'Loughlin, Christina; Murphy, Niamh F; Conlon, Carmel; O'Donovan, Aoife; Ledwidge, Mark; McDonald, Ken

    2010-02-18

    Chronic heart failure (HF) is associated with a poor Health Related Quality of Life (HRQoL). HRQoL has been shown to be a predictor of HF outcomes however, variability in the study designs make it difficult to apply these findings to a clinical setting. The aim of this study was to establish if HRQoL is a predictor of long-term mortality and morbidity in HF patients followed-up in a disease management program (DMP) and if a HRQoL instrument could be applied to aid in identifying high-risk patients within a clinical context. This is a retrospective analysis of HF patients attending a DMP with 18+/-9 months follow-up. Clinical and biochemical parameters were recorded on discharge from index HF admission and HRQoL measures were recorded at 2 weeks post index admission. 225 patients were enrolled into the study (mean age=69+/-12 years, male=61%, and 78%=systolic HF). In multivariable analysis, all dimensions of HRQoL (measured by the Minnesota Living with HF Questionnaire) were independent predictors of both mortality and readmissions particularly in patients <80 years. A significant interaction between HRQoL and age (Total((HRQoL))age: p<0.001) indicated that the association of HRQoL with outcomes diminished as age increased. These data demonstrate that HRQoL is a predictor of outcome in HF patients managed in a DMP. Younger patients (<65 years) with a Total HRQoL score of > or =50 are at high risk of an adverse outcome. In older patients > or =80 years HRQoL is not useful in predicting outcome. Copyright 2008 Elsevier Ireland Ltd. All rights reserved.

  15. Score model for predicting acute-on-chronic liver failure risk in chronic hepatitis B

    PubMed Central

    Gao, Fang-Yuan; Liu, Yao; Li, Xiao-Shu; Ye, Xie-Qiong; Sun, Le; Geng, Ming-Fan; Wang, Rui; Liu, Hui-Min; Zhou, Xiao-Bing; Gu, Li-Li; Liu, Yan-Min; Wan, Gang; Wang, Xian-Bo

    2015-01-01

    AIM: To establish a clinical scoring model to predict risk of acute-on-chronic liver failure (ACLF) in chronic hepatitis B (CHB) patients. METHODS: This was a retrospective study of 1457 patients hospitalized for CHB between October 2008 and October 2013 at the Beijing Ditan Hospital, Capital Medical University, China. The patients were divided into two groups: severe acute exacerbation (SAE) group (n = 382) and non-SAE group (n = 1075). The SAE group was classified as the high-risk group based on the higher incidence of ACLF in this group than in the non-SAE group (13.6% vs 0.4%). Two-thirds of SAE patients were randomly assigned to risk-model derivation and the other one-third to model validation. Univariate risk factors associated with the outcome were entered into a multivariate logistic regression model for screening independent risk factors. Each variable was assigned an integer value based on the regression coefficients, and the final score was the sum of these values in the derivation set. Model discrimination and calibration were assessed using area under the receiver operating characteristic curve and the Hosmer-Lemeshow test. RESULTS: The risk prediction scoring model included the following four factors: age ≥ 40 years, total bilirubin ≥ 171 μmol/L, prothrombin activity 40%-60%, and hepatitis B virus DNA > 107 copies/mL. The sum risk score ranged from 0 to 7; 0-3 identified patients with lower risk of ACLF, whereas 4-7 identified patients with higher risk. The Kaplan-Meier analysis showed the cumulative risk for ACLF and ACLF-related death in the two risk groups (0-3 and 4-7 scores) of the primary cohort over 56 d, and log-rank test revealed a significant difference (2.0% vs 33.8% and 0.8% vs 9.4%, respectively; both P < 0.0001). In the derivation and validation data sets, the model had good discrimination (C index = 0.857, 95% confidence interval: 0.800-0.913 and C index = 0.889, 95% confidence interval: 0.820-0.957, respectively) and calibration

  16. Predicting the Velocity and Azimuth of Fragments Generated by the Range Destruction or Random Failure of Rocket Casings and Tankage

    SciTech Connect

    Eck, Marshall B.; Mukunda, Meera

    1988-10-01

    The details of a predictive analytical modeling process as well as the development of normalized relations for momentum partition as a function of SRM burn time and initial geometry are discussed in this paper. Methods for applying similar modeling techniques to liquid-tankage-over-pressure failures are also discussed. These methods have been calibrated against observed SRM ascent failures and on-orbit tankage failures. Casing-quadrant sized fragments with velocities exceeding 100 m/s resulted from Titan 34D-SRM range destruct actions at 10 sec mission elapsed time (MET). Casing-quadrant sized fragments with velocities of approximately 200 m/s resulted from STS-SRM range destruct actions at 110 sec MET. Similar sized fragments for Ariane third stage and Delta second stage tankage were predicted to have maximum velocities of 260 m/s and 480 m/s respectively. Good agreement was found between the predictions and observations for five specific events and it was concluded that the methods developed have good potential for use in predicting the fragmentation process of a number of generically similar casing and tankage systems. There are three copies in the file, one of these is loose.

  17. Clinical prediction score for nasal CPAP failure in pre-term VLBW neonates with early onset respiratory distress.

    PubMed

    Pillai, Mrinal S; Sankar, Mari J; Mani, Kalaivani; Agarwal, Ramesh; Paul, Vinod K; Deorari, Ashok K

    2011-08-01

    We prospectively observed 62 pre-term very low birth weight neonates initiated on nasal continuous positive airway pressure (CPAP) for respiratory distress in the first 24 h of life to devise a clinical score for predicting its failure. CPAP was administered using short binasal prongs with conventional ventilators. On multivariate analysis, we found three variables-gestation <28 weeks [adjusted odds ratio (OR) 6.5; 95% confidence interval (CI) 1.5-28.3], pre-term premature rupture of membranes [adjusted OR 5.3; CI 1.2-24.5], and product of CPAP pressure and fraction of inspired oxygen ≥1.28 at initiation to maintain saturation between 88% and 93% [adjusted OR 3.9; CI 1.0-15.5] to be independently predictive of failure. A prediction model was devised using weighted scores of these three variables and lack of exposure to antenatal steroids. The clinical scoring system thus developed had 75% sensitivity and 70% specificity for prediction of CPAP failure (area under curve: 0.83; 95% CI 0.71-0.94).

  18. Pitfalls and Precautions When Using Predicted Failure Data for Quantitative Analysis of Safety Risk for Human Rated Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Hatfield, Glen S.; Hark, Frank; Stott, James

    2016-01-01

    Launch vehicle reliability analysis is largely dependent upon using predicted failure rates from data sources such as MIL-HDBK-217F. Reliability prediction methodologies based on component data do not take into account system integration risks such as those attributable to manufacturing and assembly. These sources often dominate component level risk. While consequence of failure is often understood, using predicted values in a risk model to estimate the probability of occurrence may underestimate the actual risk. Managers and decision makers use the probability of occurrence to influence the determination whether to accept the risk or require a design modification. The actual risk threshold for acceptance may not be fully understood due to the absence of system level test data or operational data. This paper will establish a method and approach to identify the pitfalls and precautions of accepting risk based solely upon predicted failure data. This approach will provide a set of guidelines that may be useful to arrive at a more realistic quantification of risk prior to acceptance by a program.

  19. The role of microstructure and phase distribution in the failure mechanisms and life prediction model for PSZ coatings

    NASA Technical Reports Server (NTRS)

    Sisson, R. D., Jr.; Sone, Ichiro; Biederman, R. R.

    1985-01-01

    Partially Stabilized Zirconia (PSZ) may become widely used for Thermal Barrier Coatings (TBC). Failure of these coatings can occur due to thermal fatigue in oxidizing atmospheres. The failure is due to the strains that develop due to thermal gradients, differences in thermal expansion coefficients, and oxidation of the bond coating. The role of microstructure and the cubic, tetragonal, and monoclinic phase distribution in the strain development and subsequent failure will be discussed. An X-ray diffraction technique for accurate determination of the fraction of each phase in PSZ will be applied to understanding the phase transformations and strain development. These results will be discussed in terms of developing a model for life prediction in PSZ coatings during thermal cycling.

  20. Chaos emerging in soil failure patterns observed during tillage: Normalized deterministic nonlinear prediction (NDNP) and its application

    NASA Astrophysics Data System (ADS)

    Sakai, Kenshi; Upadhyaya, Shrinivasa K.; Andrade-Sanchez, Pedro; Sviridova, Nina V.

    2017-03-01

    Real-world processes are often combinations of deterministic and stochastic processes. Soil failure observed during farm tillage is one example of this phenomenon. In this paper, we investigated the nonlinear features of soil failure patterns in a farm tillage process. We demonstrate emerging determinism in soil failure patterns from stochastic processes under specific soil conditions. We normalized the deterministic nonlinear prediction considering autocorrelation and propose it as a robust way of extracting a nonlinear dynamical system from noise contaminated motion. Soil is a typical granular material. The results obtained here are expected to be applicable to granular materials in general. From a global scale to nano scale, the granular material is featured in seismology, geotechnology, soil mechanics, and particle technology. The results and discussions presented here are applicable in these wide research areas. The proposed method and our findings are useful with respect to the application of nonlinear dynamics to investigate complex motions generated from granular materials.

  1. Acute Kidney Injury Enhances Outcome Prediction Ability of Sequential Organ Failure Assessment Score in Critically Ill Patients

    PubMed Central

    Chang, Chih-Hsiang; Fan, Pei-Chun; Chang, Ming-Yang; Tian, Ya-Chung; Hung, Cheng-Chieh; Fang, Ji-Tseng; Yang, Chih-Wei; Chen, Yung-Chang

    2014-01-01

    Introduction Acute kidney injury (AKI) is a common and serious complication in intensive care unit (ICU) patients and also often part of a multiple organ failure syndrome. The sequential organ failure assessment (SOFA) score is an excellent tool for assessing the extent of organ dysfunction in critically ill patients. This study aimed to evaluate the outcome prediction ability of SOFA and Acute Physiology and Chronic Health Evaluation (APACHE) III score in ICU patients with AKI. Methods A total of 543 critically ill patients were admitted to the medical ICU of a tertiary-care hospital from July 2007 to June 2008. Demographic, clinical and laboratory variables were prospectively recorded for post hoc analysis as predictors of survival on the first day of ICU admission. Results One hundred and eighty-seven (34.4%) patients presented with AKI on the first day of ICU admission based on the risk of renal failure, injury to kidney, failure of kidney function, loss of kidney function, and end-stage renal failure (RIFLE) classification. Major causes of the ICU admissions involved respiratory failure (58%). Overall in-ICU mortality was 37.9% and the hospital mortality was 44.7%. The predictive accuracy for ICU mortality of SOFA (areas under the receiver operating characteristic curves: 0.815±0.032) was as good as APACHE III in the AKI group. However, cumulative survival rates at 6-month follow-up following hospital discharge differed significantly (p<0.001) for SOFA score ≤10 vs. ≥11 in these ICU patients with AKI. Conclusions For patients coexisting with AKI admitted to ICU, this work recommends application of SOFA by physicians to assess ICU mortality because of its practicality and low cost. A SOFA score of ≥ “11” on ICU day 1 should be considered an indicator of negative short-term outcome. PMID:25279844

  2. Patency of Femoral Tunneled Hemodialysis Catheters and Factors Predictive of Patency Failure

    SciTech Connect

    Burton, Kirsteen R.; Guo, Lancia L. Q.; Tan, Kong T.; Simons, Martin E.; Sniderman, Kenneth W.; Kachura, John R.; Beecroft, John R.; Rajan, Dheeraj K.

    2012-12-15

    Purpose: To determine the patency rates of and factors associated with increased risk of patency failure in patients with femoral vein tunneled hemodialysis catheters. Methods: All femoral tunneled catheter insertions from 1996 to 2006 were reviewed, during which time 123 catheters were inserted. Of these, 66 were exchanges. Patients with femoral catheter failure versus those with femoral catheter patency were compared. Confounding factors, such as demographic and procedural factors, were incorporated and assessed using univariate and multivariable Cox proportional hazards regression analyses. Results: Mean catheter primary patency failure time was 96.3 days (SE 17.9 days). Primary patency at 30, 60, 90, and 180 days was 53.8%, 45.4%, 32.1%, and 27.1% respectively. Crude rates of risk of catheter failure did not suggest a benefit for patients receiving catheters introduced from one side versus the other, but more cephalad location of catheter tip was associated with improved patency. Multivariate analysis showed that patients whose catheters were on the left side (p = 0.009), were of increasing age at the time of insertion (p = 0.002) and that those who had diabetes (p = 0.001) were at significantly greater risk of catheter failure. The catheter infection rate was 1.4/1000 catheter days. Conclusion: Patients who were of a more advanced age and had diabetes were at greater risk of femoral catheter failure, whereas those who received femoral catheters from the right side were less at risk of catheter failure.

  3. Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion.

    PubMed

    Jackman, Timothy M; DelMonaco, Alex M; Morgan, Elise F

    2016-01-25

    Finite element (FE) models built from quantitative computed tomography (QCT) scans can provide patient-specific estimates of bone strength and fracture risk in the spine. While prior studies demonstrate accurate QCT-based FE predictions of vertebral stiffness and strength, the accuracy of the predicted failure patterns, i.e., the locations where failure occurs within the vertebra and the way in which the vertebra deforms as failure progresses, is less clear. This study used digital volume correlation (DVC) analyses of time-lapse micro-computed tomography (μCT) images acquired during mechanical testing (compression and anterior flexion) of thoracic spine segments (T7-T9, n=28) to measure displacements occurring throughout the T8 vertebral body at the ultimate point. These displacements were compared to those simulated by QCT-based FE analyses of T8. We hypothesized that the FE predictions would be more accurate when the boundary conditions are based on measurements of pressure distributions within intervertebral discs of similar level of disc degeneration vs. boundary conditions representing rigid platens. The FE simulations captured some of the general, qualitative features of the failure patterns; however, displacement errors ranged 12-279%. Contrary to our hypothesis, no differences in displacement errors were found when using boundary conditions representing measurements of disc pressure vs. rigid platens. The smallest displacement errors were obtained using boundary conditions that were measured directly by DVC at the T8 endplates. These findings indicate that further work is needed to develop methods of identifying physiological loading conditions for the vertebral body, for the purpose of achieving robust, patient-specific FE analyses of failure mechanisms.

  4. Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion

    PubMed Central

    Jackman, Timothy M.; DelMonaco, Alex M.; Morgan, Elise F.

    2016-01-01

    Finite element (FE) models built from quantitative computed tomography (QCT) scans can provide patient-specific estimates of bone strength and fracture risk in the spine. While prior studies demonstrate accurate QCT-based FE predictions of vertebral stiffness and strength, the accuracy of the predicted failure patterns, i.e., the locations where failure occurs within the vertebra and the way in which the vertebra deforms as failure progresses, is less clear. This study used digital volume correlation (DVC) analyses of time-lapse micro-computed tomography (µCT) images acquired during mechanical testing (compression and anterior flexion) of thoracic spine segments (T7–T9, n = 28) to measure displacements occurring throughout the T8 vertebral body at the ultimate point. These displacements were compared to those simulated by QCT-based FE analyses of T8. We hypothesized that the FE predictions would be more accurate when the boundary conditions are based on measurements of pressure distributions within intervertebral discs of similar level of disc degeneration vs. boundary conditions representing rigid platens. The FE simulations captured some of the general, qualitative features of the failure patterns; however, displacement errors ranged 12–279%. Contrary to our hypothesis, no differences in displacement errors were found when using boundary conditions representing measurements of disc pressure vs. rigid platens. The smallest displacement errors were obtained using boundary conditions that were measured directly by DVC at the T8 endplates. These findings indicate that further work is needed to develop methods of identifying physiological loading conditions for the vertebral body, for the purpose of achieving robust, patient-specific FE analyses of failure mechanisms. PMID:26792288

  5. Two-phase damage theory and crustal rock failure: the theoretical `void' limit, and the prediction of experimental data

    NASA Astrophysics Data System (ADS)

    Ricard, Yanick; Bercovici, David

    2003-12-01

    Using a classical averaging approach, we derive a two-phase theory to describe the deformation of a porous material made of a matrix containing voids. The presence and evolution of surface energy at the interface between the solid matrix and voids is taken into account with non-equilibrium thermodynamic considerations that allow storage of deformational work as surface energy on growing or newly created voids. This treatment leads to a simple description of isotropic damage that can be applied to low-cohesion media such as sandstone. In particular, the theory yields two possible solutions wherein samples can either `break' by shear localization with dilation (i.e. void creation), or undergo shear-enhanced compaction (void collapse facilitated by deviatoric stress). For a given deviatoric stress and confining pressure, the dominant solution is that with the largest absolute value of the dilation rate, |Γ|, which thus predicts that shear-localization and dilation occur at low effective pressures, while shear-enhanced compaction occurs at larger effective pressure. Stress trajectories of constant |Γ| represent potential failure envelopes that are ogive- (Gothic-arch-) shaped curves, wherein the ascending branch represents failure by dilation and shear-localization, and the descending branch denotes shear-enhanced compactive failure. The theory further predicts that the onset of dilation preceding shear-localization and failure necessarily occurs at the transition from compactive to dilational states and thus along a line connecting the peaks of constant-|Γ| ogives. Finally, the theory implies that while shear-enhanced compaction first occurs with increasing deviatoric stress (at large effective pressure), dilation will occur at higher deviatoric stresses. All of these predictions in fact compare very successfully with various experimental data. Indeed, the theory leads to a normalization where all the data of failure envelopes and dilation thresholds collapse to a

  6. Prediction of postinjury multiple-organ failure in the emergency department: development of the Denver Emergency Department Trauma Organ Failure score.

    PubMed

    Vogel, Jody A; Liao, Michael M; Hopkins, Emily; Seleno, Nicole; Byyny, Richard L; Moore, Ernest E; Gravitz, Craig; Haukoos, Jason S

    2014-01-01

    Multiple-organ failure (MOF) is common among the most seriously injured trauma patients. The ability to easily and accurately identify trauma patients in the emergency department at risk for MOF would be valuable. The aim of this study was to derive and internally validate an instrument to predict the development of MOF in adult trauma patients using clinical and laboratory data available in the emergency department. We enrolled consecutive adult trauma patients from 2005 to 2008 from the Denver Health Trauma Registry, a prospectively collected database from an urban Level 1 trauma center. Multivariable logistic regression was used to develop a clinical prediction instrument. The outcome was the development of MOF within 7 days of admission as defined by the Sequential Organ Failure Assessment (SOFA) score. A risk score was created from the final regression model by rounding the regression β coefficients to the nearest integer. Calibration and discrimination were assessed using 10-fold cross-validation. A total of 4,355 patients were included in this study. The median age was 37 years (interquartile range [IQR], 26-51 years), and 72% were male. The median Injury Severity Score (ISS) was 9 (IQR, 4-16), and 78% of the patients had blunt injury mechanisms. MOF occurred in 216 patients (5%; 95% confidence interval, 4-6%). The final risk score included patient age, intubation, systolic blood pressure, hematocrit, blood urea nitrogen, and white blood cell count and ranged from 0 to 9. The prevalence of MOF increased in an approximate exponential fashion as the score increased. The model demonstrated excellent calibration and discrimination (calibration slope, 1.0; c statistic, 0.92). We derived a simple, internally valid instrument to predict MOF in adults following trauma. The use of this score may allow early identification of patients at risk for MOF and result in more aggressive targeted resuscitation and improved resource allocation. Prognostic and epidemiologic

  7. Health literacy and global cognitive function predict e-mail but not internet use in heart failure patients.

    PubMed

    Schprechman, Jared P; Gathright, Emily C; Goldstein, Carly M; Guerini, Kate A; Dolansky, Mary A; Redle, Joseph; Hughes, Joel W

    2013-01-01

    Background. The internet offers a potential for improving patient knowledge, and e-mail may be used in patient communication with providers. However, barriers to internet and e-mail use, such as low health literacy and cognitive impairment, may prevent patients from using technological resources. Purpose. We investigated whether health literacy, heart failure knowledge, and cognitive function were related to internet and e-mail use in older adults with heart failure (HF). Methods. Older adults (N = 119) with heart failure (69.84 ± 9.09 years) completed measures of health literacy, heart failure knowledge, cognitive functioning, and internet use in a cross-sectional study. Results. Internet and e-mail use were reported in 78.2% and 71.4% of this sample of patients with HF, respectively. Controlling for age and education, logistic regression analyses indicated that higher health literacy predicted e-mail (P < .05) but not internet use. Global cognitive function predicted e-mail (P < .05) but not internet use. Only 45% used the Internet to obtain information on HF and internet use was not associated with greater HF knowledge. Conclusions. The majority of HF patients use the internet and e-mail, but poor health literacy and cognitive impairment may prevent some patients from accessing these resources. Future studies that examine specific internet and email interventions to increase HF knowledge are needed.