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Sample records for pressure support ventilation

  1. Closed-loop control of respiratory drive using pressure-support ventilation: target drive ventilation.

    PubMed

    Spahija, Jadranka; Beck, Jennifer; de Marchie, Michel; Comtois, Alain; Sinderby, Christer

    2005-05-01

    By using diaphragm electrical activity (multiple-array esophageal electrode) as an index of respiratory drive, and allowing such activity above or below a preset target range to indicate an increased or reduced demand for ventilatory assistance (target drive ventilation), we evaluated whether the level of pressure-support ventilation can be automatically adjusted in response to exercise-induced changes in ventilatory demand. Eleven healthy individuals breathed through a circuit (18 cm H2O/L/second inspiratory resistance at 1 L/second flow; 0.5-1.0 L/second expiratory flow limitation) connected to a modified ventilator. Subjects breathed for 6-minute periods at rest and during 20 and 40 W of bicycle exercise, with and without target drive ventilation (the target was set to 60% of the increase in diaphragm electrical activity observed between rest and 20 W of unassisted exercise). With target drive ventilation during exercise, the level of pressure-support ventilation was automatically increased, reaching 13.3 +/- 4.0 and 20.3 +/- 2.8 cm H2O during 20- and 40-W exercise, respectively, whereas diaphragm electrical activity was reduced to a level within the target range. Both diaphragmatic pressure-time product and end-tidal CO2 were significantly reduced with target drive ventilation at the end of the 20- (p < 0.01) and 40-W (p < 0.001) exercise periods. Minute ventilation was not altered. These results demonstrate that target drive ventilation can automatically adjust pressure-support ventilation, maintaining a constant neural drive and compensating for changes in respiratory demand. PMID:15665323

  2. Effect of Trigger Sensitivity on Redistribution of Ventilation During Pressure Support Ventilation Detected by Electrical Impedance Tomography

    PubMed Central

    Radke, Oliver C.; Schneider, Thomas; Vogel, Elisabeth; Koch, Thea

    2015-01-01

    Background: In supine position, pressure support ventilation causes a redistribution of ventilation towards the ventral regions of the lung. Theoretically, a less sensitive support trigger would cause the patient to breathe more actively, potentially attenuating the effect of positive pressure ventilation. Objectives: To quantify the effect of trigger setting, we assessed redistribution of ventilation during pressure support ventilation (PSV) using electrical impedance tomography (EIT). Patients and Methods: With approval from the local ethics committee, six orthopedic patients were enrolled. All patients had general anesthesia with a laryngeal mask airway and a standardized anesthetic regimen (sufentanil, propofol and sevoflurane). Pressure support trigger settings varied between 2 and 15 L/minute and compared to unassisted spontaneous breathing. From EIT data, the center of ventilation (COV), the fraction of the total ventilation per region of interest (ROI) and intratidal gas distribution were calculated. Results: At all trigger settings, pressure support ventilation caused a significant ventral shift of the center of ventilation compared with during spontaneous breathing, confirmed by the analysis by regions of interest. During spontaneous breathing, COV was not different from baseline values obtained before induction of anesthesia. During PSV, the intratidal regional gas distribution (ITV-analysis) revealed subtle changes during the early inspiratory phase not detected by the COV-analysis. Conclusions: Pressure support ventilation, but not spontaneous breathing, induces a significant redistribution of ventilation towards the ventral region. The sensitivity of the support trigger appears to influence the distribution of ventilation only during the early phase of inspiration. PMID:26478865

  3. Automatic control of pressure support mechanical ventilation using fuzzy logic.

    PubMed

    Nemoto, T; Hatzakis, G E; Thorpe, C W; Olivenstein, R; Dial, S; Bates, J H

    1999-08-01

    There is currently no universally accepted approach to weaning patients from mechanical ventilation, but there is clearly a feeling within the medical community that it may be possible to formulate the weaning process algorithmically in some manner. Fuzzy logic seems suited this task because of the way it so naturally represents the subjective human notions employed in much of medical decision-making. The purpose of the present study was to develop a fuzzy logic algorithm for controlling pressure support ventilation in patients in the intensive care unit, utilizing measurements of heart rate, tidal volume, breathing frequency, and arterial oxygen saturation. In this report we describe the fuzzy logic algorithm, and demonstrate its use retrospectively in 13 patients with severe chronic obstructive pulmonary disease, by comparing the decisions made by the algorithm with what actually transpired. The fuzzy logic recommendations agreed with the status quo to within 2 cm H(2)O an average of 76% of the time, and to within 4 cm H(2)O an average of 88% of the time (although in most of these instances no medical decisions were taken as to whether or not to change the level of ventilatory support). We also compared the predictions of our algorithm with those cases in which changes in pressure support level were actually made by an attending physician, and found that the physicians tended to reduce the support level somewhat more aggressively than the algorithm did. We conclude that our fuzzy algorithm has the potential to control the level of pressure support ventilation from ongoing measurements of a patient's vital signs. PMID:10430727

  4. High-Level Pressure Support Ventilation Attenuates Ventilator-Induced Diaphragm Dysfunction in Rabbits

    PubMed Central

    Ge, Huiqing; Xu, Peifeng; Zhu, Tao; Lu, Zhihua; Yuan, Yuehua; Zhou, Jiancang

    2015-01-01

    Abstract: Background: The effects of different modes of mechanical ventilation in the same ventilatory support level on ventilator-induced diaphragm dysfunction onset were assessed in healthy rabbits. Methods: Twenty New Zealand rabbits were randomly assigned to 4 groups (n = 5 in each group). Group 1: no mechanical ventilation; group 2: controlled mechanical ventilation (CMV) for 24 hours; group 3: assist/control ventilation (A/C) mode for 24 hours; group 4: high-level pressure support ventilation (PSV) mode for 24 hours. Heart rate, mean arterial blood pressure, PH, partial pressure of arterial oxygen/fraction of inspired oxygen and partial pressure of arterial carbon dioxide were monitored and diaphragm electrical activity was analyzed in the 4 groups. Caspase-3 was evaluated by protein analysis and diaphragm ultra structure was assessed by electron microscopy. Results: The centroid frequency and the ratio of high frequency to low frequency were significantly reduced in the CMV, A/C and PSV groups (P < 0.001). The percent change in centroid frequency was significantly lower in the PSV group than in the CMV and A/C groups (P = 0.001 and P = 0.028, respectively). Electromyography of diaphragm integral amplitude decreased by 90% ± 1.48%, 67.8% ± 3.13% and 70.2% ± 4.72% in the CMV, A/C and PSV groups, respectively (P < 0.001). Caspase-3 protein activation was attenuated in the PSV group compared with the CMV and A/C groups (P = 0.035 and P = 0.033, respectively). Irregular swelling of mitochondria along with fractured and fuzzy cristae was observed in the CMV group, whereas mitochondrial cristae were dense and rich in the PSV group. The mitochondrial injury scores (Flameng scores) in the PSV group were the lowest among the 3 ventilatory groups (0.93 ± 0.09 in PSV versus 2.69 ± 0.05 in the CMV [P < 0.01] and PSV versus A/C groups [2.02 ± 0.08, P < 0.01]). Conclusions: The diaphragm myoelectric activity was reduced in the PSV group, although excessive oxidative

  5. Pressure support-ventilation versus spontaneous breathing with "T-Tube" for interrupting the ventilation after cardiac operations

    PubMed Central

    Lourenço, Isabela Scali; Franco, Aline Marques; Bassetto, Solange; Rodrigues, Alfredo José

    2013-01-01

    Objective To compare pressure-support ventilation with spontaneous breathing through a T-tube for interrupting invasive mechanical ventilation in patients undergoing cardiac surgery with cardiopulmonary bypass. Methods Adults of both genders were randomly allocated to 30 minutes of either pressure-support ventilation or spontaneous ventilation with "T-tube" before extubation. Manovacuometry, ventilometry and clinical evaluation were performed before the operation, immediately before and after extubation, 1h and 12h after extubation. Results Twenty-eight patients were studied. There were no deaths or pulmonary complications. The mean aortic clamping time in the pressure support ventilation group was 62 ± 35 minutes and 68 ± 36 minutes in the T-tube group (P=0.651). The mean cardiopulmonary bypass duration in the pressure-support ventilation group was 89 ± 44 minutes and 82 ± 42 minutes in the T-tube group (P=0.75). The mean Tobin index in the pressure support ventilation group was 51 ± 25 and 64.5 ± 23 in the T-tube group (P=0.153). The duration of intensive care unit stay for the pressure support ventilation group was 2.1 ± 0.36 days and 2.3 ± 0.61 days in the T-tube group (P=0.581). The atelectasis score in the T-tube group was 0.6 ± 0.8 and 0.5 ± 0.6 (P=0.979) in the pressure support ventilation group. The study groups did not differ significantly in manovacuometric and ventilometric parameters and hospital evolution. Conclusion The two trial methods evaluated for interruption of mechanical ventilation did not affect the postoperative course of patients who underwent cardiac operations with cardiopulmonary bypass. PMID:24598949

  6. [Non-invasive ventilation in kyphoscoliosis. A comparison of a volumetric ventilator and a BIPAP support pressure device].

    PubMed

    Laserna, E; Barrot, E; Beiztegui, A; Quintana, E; Hernández, A; Castillo, J; Belaustegui, A

    2003-01-01

    Non-invasive intermittent positive pressure ventilation (NIPPV) at home is the treatment of choice for patients with chronic respiratory insufficiency secondary to severe kyphoscoliosis. Our aim was to compare clinical course, blood gases and lung function after one month of domiciliary NIPPV with two types of ventilator and to assess sleep pattern changes in patients enrolled in a prospective, randomized crossover study. Ten patients with chronic respiratory insufficiency due to kyphoscoliosis were enrolled and randomly assigned to the first device. After one month of use, the patients underwent clinical and functional examinations and polysomnographic studies while using the ventilator. The same protocol was applied with the second device after a ten-day washout period. Baseline polysomnographs showed fragmented sleep with low percentages of deep non-REM sleep and of REM sleep, as well as respiratory patterns characterized by very high frequencies coinciding with significant desaturations. In all cases symptoms and arterial blood gas improvements were significant, with no differences between the two treatment periods. The percentages of time spent with SaO2 below 90% of reference in sleep studies were significantly lower than baseline with both ventilators. All but one patient had better tolerance of the bilevel positive airway pressure (BIPAP) support mode than of the volumetric ventilator. Our study shows that NIPPV is equally effective for patients with kyphoscoliosis whether administered with a volumetric ventilator or a BIPAP device. Subjective response and tolerance seem to be slightly better with BIPAP. PMID:12550014

  7. Compensation for increase in respiratory workload during mechanical ventilation. Pressure-support versus proportional-assist ventilation.

    PubMed

    Grasso, S; Puntillo, F; Mascia, L; Ancona, G; Fiore, T; Bruno, F; Slutsky, A S; Ranieri, V M

    2000-03-01

    Variation in respiratory impedance may occur in mechanically ventilated patients. During pressure-targeted ventilatory support, this may lead to patient-ventilator asynchrony. We assessed the hypothesis that during pressure-support ventilation (PSV), preservation of minute ventilation (V E) consequent to added mechanical loads would result in an increase in respiratory rate (RR) due to the large reduction in tidal volume (VT). WITH proportional-assist ventilation (PAV), preservation of V E would occur through the preservation of VT, with a smaller effect on RR. We anticipated that this compensatory strategy would result in greater patient comfort and a reduce work of breathing. An increase in respiratory impedance was obtained by chest and abdominal binding in 10 patients during weaning from mechanical ventilation. V E remained constant in both ventilatory modes after chest and abdominal compression. During PSV, this maintenance of VE was obtained through a 58 +/- 3% increase in RR that compensated for a 29 +/- 2% reduction in VT. The magnitudes of the reduction in VT (10 +/- 3%) and of the increase in RR (14 +/- 2%) were smaller (p < 0. 001) during PAV. During both PSV and PAV, chest and abdominal compression caused increases in both the pressure-time product (PTP) of the diaphragm per minute (142.9 +/- 26.9 cm H(2)O. s/min, PSV, and 117.6 +/- 16.4 cm H(2)O. s/min, PAV) and per liter (13.4 +/- 2.5 cm H(2)O. s/L, PSV, and 9.6 +/- 0.7 cm H(2)O. s/L, PAV). These increments were greater (p < 0.001) during PSV than during PAV. The capability of keeping VT and V E constant through increases in inspiratory effort after increases in mechanical loads is relatively preserved only during PAV. The ventilatory response to an added respiratory load during PSV required greater muscle effort than during PAV. PMID:10712328

  8. Effectiveness of Inspiratory Termination Synchrony with Automatic Cycling During Noninvasive Pressure Support Ventilation.

    PubMed

    Chen, Yuqing; Cheng, Kewen; Zhou, Xin

    2016-01-01

    BACKGROUND Pressure support ventilation (PSV) is a standard method for non-invasive home ventilation. A bench study was designed to compare the effectiveness of patient-ventilator inspiratory termination synchronization with automated and conventional triggering in various respiratory mechanics models. MATERIAL AND METHODS Two ventilators, the Respironics V60 and Curative Flexo ST 30, connected to a Hans Rudolph Series 1101 lung simulator, were evaluated using settings that simulate lung mechanics in patients with chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), or normal lungs. Ventilators were operated with automated (Auto-Trak) or conventional high-, moderate-, and low-sensitivity flow-cycling software algorithms, 5 cmH2O or 15 cmH2O pressure support, 5 cmH2O positive end-expiratory pressure (PEEP), and an air leak of 25-28 L/min. RESULTS Both ventilators adapted to the system leak without requiring adjustment of triggering settings. In all simulated lung conditions, automated cycling resulted in shorter triggering delay times (<100 ms) and lower triggering pressure-time product (PTPt) values. Tidal volumes (VT) increased with lower conventional cycling sensitivity level. In the COPD model, automated cycling had higher leak volumes and shorter cycling delay times than in conventional cycling. Asynchronous events were rare. Inspiratory time (Tinsp), peak expiratory flow (PEF), and cycling off delay time (Cdelay) increased as a result of reduction in conventional cycling sensitivity level. In the ARDS and normal adult lung models, premature cycling was frequent at the high-sensitive cycling level. CONCLUSIONS Overall, the Auto-Trak protocol showed better patient-machine cycling synchronization than conventional triggering. This was evident by shorter triggering time delays and lower PTPt. PMID:27198165

  9. Effectiveness of Inspiratory Termination Synchrony with Automatic Cycling During Noninvasive Pressure Support Ventilation

    PubMed Central

    Chen, Yuqing; Cheng, Kewen; Zhou, Xin

    2016-01-01

    Background Pressure support ventilation (PSV) is a standard method for non-invasive home ventilation. A bench study was designed to compare the effectiveness of patient-ventilator inspiratory termination synchronization with automated and conventional triggering in various respiratory mechanics models. Material/Methods Two ventilators, the Respironics V60 and Curative Flexo ST 30, connected to a Hans Rudolph Series 1101 lung simulator, were evaluated using settings that simulate lung mechanics in patients with chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), or normal lungs. Ventilators were operated with automated (Auto-Trak) or conventional high-, moderate-, and low-sensitivity flow-cycling software algorithms, 5 cmH2O or 15 cmH2O pressure support, 5 cmH2O positive end-expiratory pressure (PEEP), and an air leak of 25–28 L/min. Results Both ventilators adapted to the system leak without requiring adjustment of triggering settings. In all simulated lung conditions, automated cycling resulted in shorter triggering delay times (<100 ms) and lower triggering pressure-time product (PTPt) values. Tidal volumes (VT) increased with lower conventional cycling sensitivity level. In the COPD model, automated cycling had higher leak volumes and shorter cycling delay times than in conventional cycling. Asynchronous events were rare. Inspiratory time (Tinsp), peak expiratory flow (PEF), and cycling off delay time (Cdelay) increased as a result of reduction in conventional cycling sensitivity level. In the ARDS and normal adult lung models, premature cycling was frequent at the high-sensitive cycling level. Conclusions Overall, the Auto-Trak protocol showed better patient-machine cycling synchronization than conventional triggering. This was evident by shorter triggering time delays and lower PTPt. PMID:27198165

  10. Analysis of the mechanisms of expiratory asynchrony in pressure support ventilation: a mathematical approach.

    PubMed

    Yamada, Y; Du, H L

    2000-06-01

    A mathematical model was developed to analyze the mechanisms of expiratory asynchrony during pressure support ventilation (PSV). Solving the model revealed several results. 1) Ratio of the flow at the end of patient neural inspiration to peak inspiratory flow (VTI/V(peak)) during PSV is determined by the ratio of time constant of the respiratory system (tau) to patient neural inspiratory time (TI) and the ratio of the set pressure support (Pps) level to maximal inspiratory muscle pressure (Pmus max). 2) VTI/V(peak) is affected more by tau/TI than by Pps/Pmus max. VTI/V(peak) increases in a sigmoidal relationship to tau/TI. An increase in Pps/Pmus max slightly shifts the VTI/V(peak)-tau/TI curve to the right, i.e., VTI/V(peak) becomes lower as Pps/Pmus max increases at the same tau/TI. 3) Under the selected adult respiratory mechanics, VTI/V(peak) ranges from 1 to 85% and has an excellent linear correlation with tau/TI. 4) In mechanical ventilators, single fixed levels of the flow termination criterion will always have chances of both synchronized termination and asynchronized termination, depending on patient mechanics. An increase in tau/TI causes more delayed and less premature termination opportunities. An increase in Pps/Pmus max narrows the synchronized zone, making inspiratory termination predisposed to be in asynchrony. Increasing the expiratory trigger sensitivity of a ventilator shifts the synchronized zone to the right, causing less delayed and more premature termination. Automation of expiratory trigger sensitivity in future mechanical ventilators may also be possible. In conclusion, our model provides a useful tool to analyze the mechanisms of expiratory asynchrony in PSV. PMID:10846029

  11. Performance Characteristics of Seven Bilevel Mechanical Ventilators in Pressure-Support Mode with Different Cycling Criteria: A Comparative Bench Study

    PubMed Central

    Chen, Yuqing; Cheng, Kewen; Zhou, Xin

    2015-01-01

    Background Pressure support ventilation from a bilevel device is a standard technique for non-invasive home ventilation. A bench study was designed to compare the performance and patient-ventilator synchronization of 7 bilevel ventilators, in the presence of system leaks. Material/Methods Ventilators were connected to a Hans Rudolph Series 1101 lung simulator (compliance, 50 mL/cmH2O; expiratory resistance, 20 cmH2O/L/s; respiratory rate, 15 breaths/min; inspiratory time, 1.0 s). All ventilators were set at 15 cmH2O pressure support and 5 cmH2O positive end-expiratory pressure. Tests were conducted at 2 system leaks (12–15 and 25–28 L/min). The performance characteristics and patient-ventilator asynchrony were assessed, including flow, airway pressure, time, and workload. Results The Breas Vivo30 could not synchronize with the simulator (frequent auto-triggering) at a leak of 25–28 L/min, but provided stable assisted ventilation when the leak was 12–15 L/min. Missed efforts and back-up ventilation occurred for the Weinmann VENTImotion and Airox Smartair Plus, requiring adjustment of trigger effort. All ventilators had a short trigger delay time (<200 ms), but significant differences between devices were found in triggering workload, pressurization appearance, tidal volume, and peak inspiratory flow. Premature cycling was frequent when the inspiratory termination criteria were at the highest sensitivity. Cycling synchronization was considerably improved by modifying expiratory triggering sensitivity settings, when available. Conclusions Performance and triggering workload varied significantly between bilevel ventilators, possibly due to software algorithm differences. Adjusting the cycling criteria settings can alter the shape of the inspiratory phase and peak expiratory flow, and improve patient-ventilator synchrony. PMID:25619202

  12. Haemodynamic effects of pressure support and PEEP ventilation by nasal route in patients with stable chronic obstructive pulmonary disease.

    PubMed Central

    Ambrosino, N; Nava, S; Torbicki, A; Riccardi, G; Fracchia, C; Opasich, C; Rampulla, C

    1993-01-01

    BACKGROUND--Intermittent positive pressure ventilation applied through a nasal mask has been shown to be useful in the treatment of chronic respiratory insufficiency. Pressure support ventilation is an assisted mode of ventilation which is being increasingly used. Invasive ventilation with intermittent positive pressure, with or without positive end expiratory pressure (PEEP), has been found to affect venous return and cardiac output. This study evaluated the acute haemodynamic support ventilation by nasal mask, with and without the application of PEEP, in patients with severe stable chronic obstructive pulmonary disease and hypercapnia. METHODS--Nine patients with severe stable chronic obstructive pulmonary disease performed sessions lasting 10 minutes each of pressure support ventilation by nasal mask while undergoing right heart catheterisation for clinical evaluation. In random order, four sessions of nasal pressure support ventilation were applied consisting of: (1) peak inspiratory pressure (PIP) 10 cm H2O, PEEP 0 cm H2O; (2) PIP 10 cm H2O, PEEP 5 cm H2O; (3) PIP 20 cm H2O, PEEP 0 cm H2O; (4) PIP 20 cm H2O, PEEP 5 cm H2O. RESULTS--Significant increases in arterial oxygen tension (Pao2) and saturation (Sao2) and significant reductions in arterial carbon dioxide tension (PaCO2) and changes in pH were observed with a PIP of 20 cm H2O. Statistical analysis showed that the addition of 5 cm H2O PEEP did not further improve arterial blood gas tensions. Comparison of baseline values with measurements performed after 10 minutes of each session of ventilation showed that all modes of ventilation except PIP 10 cm H2O without PEEP induced a small but significant increase in pulmonary capillary wedge pressure. In comparison with baseline values, a significant decrease in cardiac output and oxygen delivery was induced only by the addition of PEEP to both levels of PIP. CONCLUSIONS--In patients with severe stable chronic obstructive pulmonary disease and hypercapnia

  13. Comparison of Two Levels of Pressure Support Ventilation on Success of Extubation in Preterm Neonates: A Randomized Clinical Trial

    PubMed Central

    Farhadi, Roya; Lotfi, Hamid Reza; Alipour, Abbas; Nakhshab, Maryam; Ghaffari, Vajiheh; Hashemi, Seyyed Abbas

    2016-01-01

    Background: Pressure Support Ventilation (PSV) is one of the modes of mechanical ventilation that can be used alone as a weaning strategy in neonates. However, studies on the appropriate pressure level for this mode in neonates are limited. Objectives: Because the use of adequate pressure support in this mode, keeping the appropriate neonate’s tidal volume, and preventing the respiratory complications, this study was aimed to compare extubation failure in the two levels of pressure support ventilation of 10 and 14 cmH2O when removing the neonates from the ventilator. Materials & Methods: In this randomized clinical trial 50 premature infants of 27-37 weeks with respiratory distress syndrome (RDS) were under mechanical ventilation for at least 48 hours, were randomly assigned to two groups. One group was extubated in PSV mode with pressure of 14 cmH2O and the other with 10 cmH2O. Extubation failure rate and complications such as pneumothorax, death and respiratory parameters were compared in the two groups. Results: Twenty five neonates in each group were assessed. Weaning time, extubation failure rate, and mean airway pressure was lesser in PSV of 10 cmH20 group than Level of 14 cmH2O and those differences were statistically significant (P<0.05). Difference between work of breathing, ventilation time, pneumothorax and mortality rate between two groups were not statistically significant (P>0.05). Conclusion: The results of our study show that extubation of the neonates using 10 CmH2O in PSV mode increases the success rate of extubation. Although when Volume- assured PSV can be used, it is more logical to use it for guaranteeing tidal volume, but using the appropriate level of pressure support when the PSV mode is used alone is inevitable and further studies are necessary to demonstrate the level of pressure in this mode. PMID:26383214

  14. Chest compression with a higher level of pressure support ventilation: effects on secretion removal, hemodynamics, and respiratory mechanics in patients on mechanical ventilation*

    PubMed Central

    Naue, Wagner da Silva; Forgiarini, Luiz Alberto; Dias, Alexandre Simões; Vieira, Silvia Regina Rios

    2014-01-01

    OBJECTIVE: To determine the efficacy of chest compression accompanied by a 10-cmH2O increase in baseline inspiratory pressure on pressure support ventilation, in comparison with that of aspiration alone, in removing secretions, normalizing hemodynamics, and improving respiratory mechanics in patients on mechanical ventilation. METHODS: This was a randomized crossover clinical trial involving patients on mechanical ventilation for more than 48 h in the ICU of the Porto Alegre Hospital de Clínicas, in the city of Porto Alegre, Brazil. Patients were randomized to receive aspiration alone (control group) or compression accompanied by a 10-cmH2O increase in baseline inspiratory pressure on pressure support ventilation (intervention group). We measured hemodynamic parameters, respiratory mechanics parameters, and the amount of secretions collected. RESULTS: We included 34 patients. The mean age was 64.2 ± 14.6 years. In comparison with the control group, the intervention group showed a higher median amount of secretions collected (1.9 g vs. 2.3 g; p = 0.004), a greater increase in mean expiratory tidal volume (16 ± 69 mL vs. 56 ± 69 mL; p = 0.018), and a greater increase in mean dynamic compliance (0.1 ± 4.9 cmH2O vs. 2.8 ± 4.5 cmH2O; p = 0.005). CONCLUSIONS: In this sample, chest compression accompanied by an increase in pressure support significantly increased the amount of secretions removed, the expiratory tidal volume, and dynamic compliance. (ClinicalTrials.gov Identifier:NCT01155648 [http://www.clinicaltrials.gov/]) PMID:24626270

  15. Evaluation of carbon dioxide rebreathing during pressure support ventilation with airway management system (BiPAP) devices.

    PubMed

    Lofaso, F; Brochard, L; Touchard, D; Hang, T; Harf, A; Isabey, D

    1995-09-01

    The purpose of this study was to evaluate whether carbon dioxide (CO2) rebreathing occurs in acute respiratory failure patients ventilated using the standard airway management system (BiPAP pressure support ventilator; Respironics; Murrysville, Pa) with positive inspiratory airway pressure and a minimal level of positive end-expiratory pressure (PEEP) and whether any CO2 rebreathing may be efficiently prevented by the addition of a nonrebreathing valve to the BiPAP system circuit. In the first part of the study, the standard device was tested on a lung model with a nonrebreathing valve (BiPAP-NRV) and with the usual Whisper Swivel connector (BiPAP-uc). With the BiPAP-uc device, the resident volume of expired air in the inspiratory circuit at the end of expiration (RVEA) was 55% of the tidal volume (VT) when the inspiratory pressure was 10 cm H2O and the frequency was at 15 cycles per minute. The BiPAP-NRV device efficiently prevented CO2 rebreathing but resulted in a slight decrease in VT, which was due to a significant increase in external PEEP (2.4 vs 1.3 cm H2O) caused by the additional expiratory valve resistance. For similar reasons, both the pressure swing necessary to trigger pressure support and the imposed expiratory work were increased in the lung model when the nonrebreathing valve was used. In the second part of the study, seven patients weaned from mechanical ventilation were investigated using a randomized crossover design to compare three situations: pressure support ventilation with a conventional intensive care ventilator (CIPS), BiPAP system use, and BiPAP-NRV. When we compared the BiPAP system use with the other two systems, we observed no significant effect on blood gases but found significant increases in VT, minute ventilation, and work of breathing. These findings are experimental and are clinical evidence that significant CO2 rebreathing occurs with the standard BiPAP system. This drawback can be overcome by using a non-rebreathing valve

  16. Intraoperative Autotriggered Pressure Support Ventilation Resistant to Increased Flow Trigger Threshold.

    PubMed

    Benitez Lopez, Julio; Rao, Sripad P; McNeer, Richard R; Dudaryk, Roman

    2016-07-01

    Oscillations from cardiac pulsations are normally transmitted to mediastinal structures without any consequence. Autotriggering (AT) of mechanical ventilation occurs when an inspiratory trigger, typically negative inspiratory flow in anesthesia ventilators, is met in the absence of patient effort. AT can lead to respiratory alkalosis, opioid overdose, prolonged mechanical ventilation, and lung hyperinflation. This entity has been reported in both critical care and operating room environments. Increasing the flow trigger usually resolves AT in all cases. We report a case of AT that failed to respond to increasing the flow trigger threshold to its maximal value on the GE Datex-Ohmeda Avance S5® anesthesia station. PMID:27224041

  17. Ventilatory failure, ventilator support, and ventilator weaning.

    PubMed

    Tobin, Martin J; Laghi, Franco; Jubran, Amal

    2012-10-01

    The development of acute ventilatory failure represents an inability of the respiratory control system to maintain a level of respiratory motor output to cope with the metabolic demands of the body. The level of respiratory motor output is also the main determinant of the degree of respiratory distress experienced by such patients. As ventilatory failure progresses and patient distress increases, mechanical ventilation is instituted to help the respiratory muscles cope with the heightened workload. While a patient is connected to a ventilator, a physician's ability to align the rhythm of the machine with the rhythm of the patient's respiratory centers becomes the primary determinant of the level of rest accorded to the respiratory muscles. Problems of alignment are manifested as failure to trigger, double triggering, an inflationary gas-flow that fails to match inspiratory demands, and an inflation phase that persists after a patient's respiratory centers have switched to expiration. With recovery from disorders that precipitated the initial bout of acute ventilatory failure, attempts are made to discontinue the ventilator (weaning). About 20% of weaning attempts fail, ultimately, because the respiratory controller is unable to sustain ventilation and this failure is signaled by development of rapid shallow breathing. Substantial advances in the medical management of acute ventilatory failure that requires ventilator assistance are most likely to result from research yielding novel insights into the operation of the respiratory control system. PMID:23720268

  18. Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

    PubMed Central

    Shi, Yan; Ren, Shuai; Cai, Maolin; Xu, Weiqing; Deng, Qiyou

    2014-01-01

    Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems. PMID:25197318

  19. Pressure dynamic characteristics of pressure controlled ventilation system of a lung simulator.

    PubMed

    Shi, Yan; Ren, Shuai; Cai, Maolin; Xu, Weiqing; Deng, Qiyou

    2014-01-01

    Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems. PMID:25197318

  20. 21 CFR 868.5935 - External negative pressure ventilator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false External negative pressure ventilator. 868.5935... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5935 External negative pressure ventilator. (a) Identification. An external negative pressure ventilator (e.g., iron lung, cuirass) is...

  1. 21 CFR 868.5935 - External negative pressure ventilator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false External negative pressure ventilator. 868.5935... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5935 External negative pressure ventilator. (a) Identification. An external negative pressure ventilator (e.g., iron lung, cuirass) is...

  2. 21 CFR 868.5935 - External negative pressure ventilator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false External negative pressure ventilator. 868.5935... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5935 External negative pressure ventilator. (a) Identification. An external negative pressure ventilator (e.g., iron lung, cuirass) is...

  3. 21 CFR 868.5935 - External negative pressure ventilator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External negative pressure ventilator. 868.5935... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5935 External negative pressure ventilator. (a) Identification. An external negative pressure ventilator (e.g., iron lung, cuirass) is...

  4. A decision support system to determine optimal ventilator settings

    PubMed Central

    2014-01-01

    Background Choosing the correct ventilator settings for the treatment of patients with respiratory tract disease is quite an important issue. Since the task of specifying the parameters of ventilation equipment is entirely carried out by a physician, physician’s knowledge and experience in the selection of these settings has a direct effect on the accuracy of his/her decisions. Nowadays, decision support systems have been used for these kinds of operations to eliminate errors. Our goal is to minimize errors in ventilation therapy and prevent deaths caused by incorrect configuration of ventilation devices. The proposed system is designed to assist less experienced physicians working in the facilities without having lung mechanics like cottage hospitals. Methods This article describes a decision support system proposing the ventilator settings required to be applied in the treatment according to the patients’ physiological information. The proposed model has been designed to minimize the possibility of making a mistake and to encourage more efficient use of time in support of the decision making process while the physicians make critical decisions about the patient. Artificial Neural Network (ANN) is implemented in order to calculate frequency, tidal volume, FiO2 outputs, and this classification model has been used for estimation of pressure support / volume support outputs. For the obtainment of the highest performance in both models, different configurations have been tried. Various tests have been realized for training methods, and a number of hidden layers mostly affect factors regarding the performance of ANNs. Results The physiological information of 158 respiratory patients over the age of 60 and were treated in three different hospitals between the years 2010 and 2012 has been used in the training and testing of the system. The diagnosed disease, core body temperature, pulse, arterial systolic pressure, diastolic blood pressure, PEEP, PSO2, pH, pCO2

  5. Synchronized Nasal Intermittent Positive Pressure Ventilation of the Newborn: Technical Issues and Clinical Results.

    PubMed

    Moretti, Corrado; Gizzi, Camilla; Montecchia, Francesco; Barbàra, Caterina Silvia; Midulla, Fabio; Sanchez-Luna, Manuel; Papoff, Paola

    2016-01-01

    Although mechanical ventilation via an endotracheal tube has undoubtedly led to improvement in neonatal survival in the last 40 years, the prolonged use of this technique may predispose the infant to development of many possible complications including bronchopulmonary dysplasia. Avoiding mechanical ventilation is thought to be a critical goal, and different modes of noninvasive respiratory support beyond nasal continuous positive airway pressure, such as nasal intermittent positive pressure ventilation and synchronized nasal intermittent positive pressure ventilation, are also available and may reduce intubation rate. Several trials have demonstrated that the newer modes of noninvasive ventilation are more effective than nasal continuous positive airway pressure in reducing extubation failure and may also be more helpful as modes of primary support to treat respiratory distress syndrome after surfactant and for treatment of apnea of prematurity. With synchronized noninvasive ventilation, these benefits are more consistent, and different modes of synchronization have been reported. Although flow-triggering is the most common mode of synchronization, this technique is not reliable for noninvasive ventilation in neonates because it is affected by variable leaks at the mouth and nose. This review discusses the mechanisms of action, benefits and limitations of noninvasive ventilation, describes the different modes of synchronization and analyzes the technical characteristics, properties and clinical results of a flow-sensor expressly developed for synchronized noninvasive ventilation. PMID:27251453

  6. Assisted Ventilation.

    PubMed

    Dries, David J

    2016-01-01

    Controlled Mechanical Ventilation may be essential in the setting of severe respiratory failure but consequences to the patient including increased use of sedation and neuromuscular blockade may contribute to delirium, atelectasis, and diaphragm dysfunction. Assisted ventilation allows spontaneous breathing activity to restore physiological displacement of the diaphragm and recruit better perfused lung regions. Pressure Support Ventilation is the most frequently used mode of assisted mechanical ventilation. However, this mode continues to provide a monotonous pattern of support for respiration which is normally a dynamic process. Noisy Pressure Support Ventilation where tidal volume is varied randomly by the ventilator may improve ventilation and perfusion matching but the degree of support is still determined by the ventilator. Two more recent modes of ventilation, Proportional Assist Ventilation and Neurally Adjusted Ventilatory Assist (NAVA), allow patient determination of the pattern and depth of ventilation. Proposed advantages of Proportional Assist Ventilation and NAVA include decrease in patient ventilator asynchrony and improved adaptation of ventilator support to changing patient demand. Work of breathing can be normalized with these modes as well. To date, however, a clear pattern of clinical benefit has not been demonstrated. Existing challenges for both of the newer assist modes include monitoring patients with dynamic hyperinflation (auto-positive end expiratory pressure), obstructive lung disease, and air leaks in the ventilator system. NAVA is dependent on consistent transduction of diaphragm activity by an electrode system placed in the esophagus. Longevity of effective support with this technique is unclear. PMID:25501776

  7. Pressure versus volume controlled modes in invasive mechanical ventilation.

    PubMed

    Garnero, A J; Abbona, H; Gordo-Vidal, F; Hermosa-Gelbard, C

    2013-05-01

    The first generation of mechanical ventilators were controlled and cycled by pressure. Unfortunately, they did not allow control of the delivered tidal volume under changes in the dynamics of the respiratory system. This led to a second generation of ventilators that allowed volume control, hence favoring the ventilatory strategy based on normalization of the arterial gases. Studies conducted in the 1980s which related lung injury to the high ventilator pressures utilized while treating acute respiratory distress syndrome patients renewed interest in pressure-controlled mechanical ventilation. In addition, new evidence became available, leading to the development of pulmonary protective strategies aiming at preventing the progression of ventilator-induced lung injury. This review provides a detailed description of the control of pressure or volume using certain ventilatory modes, and offers a general view of their advantages and disadvantages, based on the latest available evidence. PMID:23260264

  8. Anaesthesia ventilators

    PubMed Central

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-01-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits. PMID:24249886

  9. MEASUREMENT OF FRICTIONAL PRESSURE DIFFERENTIALS DURING A VENTILATION SURVEY

    SciTech Connect

    B.S. Prosser, PE; I.M. Loomis, PE, PhD

    2003-11-03

    During the course of a ventilation survey, both airflow quantity and frictional pressure losses are measured and quantified. The measurement of airflow has been extensively studied as the vast majority of ventilation standards/regulations are tied to airflow quantity or velocity. However, during the conduct of a ventilation survey, measurement of airflow only represents half of the necessary parameters required to directly calculate the airway resistance. The measurement of frictional pressure loss is an often misunderstood and misapplied part of the ventilation survey. This paper compares the two basic methods of frictional pressure drop measurements; the barometer and the gauge and tube. Personal experiences with each method will be detailed along with the authors' opinions regarding the applicability and conditions favoring each method.

  10. Early airway pressure release ventilation prevents ARDS-a novel preventive approach to lung injury.

    PubMed

    Roy, Shreyas; Habashi, Nader; Sadowitz, Benjamin; Andrews, Penny; Ge, Lin; Wang, Guirong; Roy, Preyas; Ghosh, Auyon; Kuhn, Michael; Satalin, Joshua; Gatto, Louis A; Lin, Xin; Dean, David A; Vodovotz, Yoram; Nieman, Gary

    2013-01-01

    . Quantitative histologic scoring showed improvements in all stigmata of ARDS in the APRV group versus the LTV ventilation (P < 0.05). Airway pressure release ventilation had significantly lower lung edema (wet-dry weight) than LTV ventilation (P < 0.05). Protective ventilation with APRV immediately following injury prevents development of ARDS. Reduction in lung edema, preservation of lung E-cadherin, and surfactant protein A abundance in BALF suggest that APRV attenuates lung permeability, edema, and surfactant degradation. Protective ventilation could change the clinical paradigm from supportive care for ARDS with LTV ventilation to preventing development of ARDS with APRV. PMID:23247119

  11. Control system design for a Continuous Positive Airway Pressure ventilator.

    PubMed

    Chen, Zheng-Long; Hu, Zhao-Yan; Dai, Hou-De

    2012-01-01

    Continuous Positive Airway Pressure (CPAP) ventilation remains a mainstay treatment for obstructive sleep apnea syndrome (OSAS). Good pressure stability and pressure reduction during exhalation are of major importance to ensure clinical efficacy and comfort of CPAP therapy. In this study an experimental CPAP ventilator was constructed using an application-specific CPAP blower/motor assembly and a microprocessor. To minimize pressure variations caused by spontaneous breathing as well as the uncomfortable feeling of exhaling against positive pressure, we developed a composite control approach including the feed forward compensator and feedback proportional-integral-derivative (PID) compensator to regulate the pressure delivered to OSAS patients. The Ziegler and Nichols method was used to tune PID controller parameters. And then we used a gas flow analyzer (VT PLUS HF) to test pressure curves, flow curves and pressure-volume loops for the proposed CPAP ventilator. The results showed that it met technical criteria for sleep apnea breathing therapy equipment. Finally, the study made a quantitative comparison of pressure stability between the experimental CPAP ventilator and commercially available CPAP devices. PMID:22296604

  12. Control system design for a continuous positive airway pressure ventilator

    PubMed Central

    2012-01-01

    Continuous Positive Airway Pressure (CPAP) ventilation remains a mainstay treatment for obstructive sleep apnea syndrome (OSAS). Good pressure stability and pressure reduction during exhalation are of major importance to ensure clinical efficacy and comfort of CPAP therapy. In this study an experimental CPAP ventilator was constructed using an application-specific CPAP blower/motor assembly and a microprocessor. To minimize pressure variations caused by spontaneous breathing as well as the uncomfortable feeling of exhaling against positive pressure, we developed a composite control approach including the feed forward compensator and feedback proportional-integral-derivative (PID) compensator to regulate the pressure delivered to OSAS patients. The Ziegler and Nichols method was used to tune PID controller parameters. And then we used a gas flow analyzer (VT PLUS HF) to test pressure curves, flow curves and pressure-volume loops for the proposed CPAP ventilator. The results showed that it met technical criteria for sleep apnea breathing therapy equipment. Finally, the study made a quantitative comparison of pressure stability between the experimental CPAP ventilator and commercially available CPAP devices. PMID:22296604

  13. Pressure Controlled Ventilation to Induce Acute Lung Injury in Mice

    PubMed Central

    Koeppen, Michael; Eckle, Tobias; Eltzschig, Holger K.

    2011-01-01

    Murine models are extensively used to investigate acute injuries of different organs systems (1-34). Acute lung injury (ALI), which occurs with prolonged mechanical ventilation, contributes to morbidity and mortality of critical illness, and studies on novel genetic or pharmacological targets are areas of intense investigation (1-3, 5, 8, 26, 30, 33-36). ALI is defined by the acute onset of the disease, which leads to non-cardiac pulmonary edema and subsequent impairment of pulmonary gas exchange (36). We have developed a murine model of ALI by using a pressure-controlled ventilation to induce ventilator-induced lung injury (2). For this purpose, C57BL/6 mice are anesthetized and a tracheotomy is performed followed by induction of ALI via mechanical ventilation. Mice are ventilated in a pressure-controlled setting with an inspiratory peak pressure of 45 mbar over 1 - 3 hours. As outcome parameters, pulmonary edema (wet-to-dry ratio), bronchoalveolar fluid albumin content, bronchoalveolar fluid and pulmonary tissue myeloperoxidase content and pulmonary gas exchange are assessed (2). Using this technique we could show that it sufficiently induces acute lung inflammation and can distinguish between different treatment groups or genotypes (1-3, 5). Therefore this technique may be helpful for researchers who pursue molecular mechanisms involved in ALI using a genetic approach in mice with gene-targeted deletion. PMID:21587159

  14. [Invasive ventilation. Classification, technique and clinical experiences with BiPAP/APRV (Biphasic Positive Airway Pressure/Airway Pressure Release Ventilation)].

    PubMed

    Antonsen, K; Jacobsen, E; Pedersen, J E; Porsborg, P A; Bonde, J

    1996-01-22

    BiPAP (bilevel or biphasic positive airway pressure) and APRV (airway pressure release ventilation) are new, and from a technical viewpoint closely related techniques recently introduced to the field of invasive ventilatory support. BiPAP/APRV can be described as a pressure controlled continuous high flow positive airway pressure system with a time-cycled change between a high inspiratory pressure level and a lower expiratory pressure level. Due to highly sensitive valves placed in the inspiratory and expiratory part of the system, unrestricted spontaneous breathing is possible at any moment of the mechanically supported ventilatory cycle. During invasive ventilation BiPAP offers potential advantages by allowing unrestricted spontaneous breathing thus reducing the need for sedation and facilitating weaning. APRV has primarily been investigated in conditions of moderate to severe acute lung injury and it seems that APRV is associated with less detrimental effects on the cardiopulmonary system compared to conventional ventilatory strategies. Apart from a review of the literature the article gives a classification and a technical description of the systems and focuses on the practical approach to BiPAP/APRV, e.g. the initiation and adjustment of respiratory support and the weaning from ventilatory support when applying these techniques. PMID:8638300

  15. Intradiscal pressure variation under spontaneous ventilation

    NASA Astrophysics Data System (ADS)

    Roriz, Paulo; Ferreira, J.; Potes, J. C.; Oliveira, M. T.; Santos, J. L.; Simões, J. A.; Frazão, O.

    2014-05-01

    The pressure measured in the intervertebral discs is a response to the loads acting on the spine. External loads, such as the reaction forces resulting from locomotion, manual handling and collisions are probably the most relevant in studying spine trauma. However, the physiological functions such as breathing and hearth rate also participate in subtle variations of intradiscal pressure that can be observed only in vivo at resting. Present work is an effort to measure the effect of breathing on intradiscal pressure of an anesthetized sheep.

  16. Ventilator-induced pulse pressure variation in neonates.

    PubMed

    Heskamp, Linda; Lansdorp, Benno; Hopman, Jeroen; Lemson, Joris; de Boode, Willem-Pieter

    2016-02-01

    During positive pressure ventilation, arterial pressure variations, like the pulse pressure variation (PPV), are observed in neonates. However, the frequency of the PPV does not always correspond with the respiratory rate. It is hypothesized that PPV is caused by cardiopulmonary interaction, but that this mismatch is related to the low respiratory rate/heart rate ratio. Therefore, the goal of this study is to investigate the relation between PPV and ventilation in neonates. A prospective observational cross-sectional study was carried out in a third-level neonatal intensive care unit in a university hospital. Neonates on synchronized intermittent mandatory ventilation (SIMV) or high-frequency ventilation (HFV) participated in the study. The arterial blood pressure was continuously monitored in 20 neonates on SIMV and 10 neonates on HFV. In neonates on SIMV the CO2 waveform and neonates on HFV the thorax impedance waveform were continuously monitored and defined as the respiratory signal. Correlation and coherence between the respiratory signal and pulse pressure were determined. The correlation between the respiratory signal and pulse pressure was -0.64 ± 0.18 and 0.55 ± 0.16 and coherence at the respiratory frequency was 0.95 ± 0.11 and 0.76 ± 0.4 for SIMV and HFV, respectively. The arterial pressure variations observed in neonates on SIMV or HFV are related to cardiopulmonary interaction. Despite this relation, it is not likely that PPV will reliably predict fluid responsiveness in neonates due to physiological aliasing. PMID:26908715

  17. Pressure losses across multiple fittings in ventilation ducts.

    PubMed

    Ai, Z T; Mak, C M

    2013-01-01

    The accurate prediction of pressure losses across in-duct fittings is of significance in relation to the accurate sizing and good energy efficiency of air-delivery systems. Current design guides provide design methods and data for the prediction of pressure losses only for a single and isolated fitting. This study presents an investigation of pressure losses across multiple interactive in-duct fittings in a ventilation duct. A laboratory measurement of pressure losses across one fitting and multiple fittings in a ventilation duct is carried out. The pressure loss across multiple interactive fittings is lower than that across multiple similar individual fittings, while the percentage decrease is dependent on the configuration and combination of the fittings. This implies that the pressure loss across multiple closely mounted fittings calculated by summing the pressure losses across individual fittings, as provided in the ASHRAE handbook and the CIBSE guide, is overpredicted. The numerical prediction of the pressure losses across multiple fittings using the large-eddy simulation (LES) model shows good agreement with the measured data, suggesting that this model is a useful tool in ductwork design and can help to save experimental resources and improve experimental accuracy and reliability. PMID:24385871

  18. Pressure Losses across Multiple Fittings in Ventilation Ducts

    PubMed Central

    Ai, Z. T.; Mak, C. M.

    2013-01-01

    The accurate prediction of pressure losses across in-duct fittings is of significance in relation to the accurate sizing and good energy efficiency of air-delivery systems. Current design guides provide design methods and data for the prediction of pressure losses only for a single and isolated fitting. This study presents an investigation of pressure losses across multiple interactive in-duct fittings in a ventilation duct. A laboratory measurement of pressure losses across one fitting and multiple fittings in a ventilation duct is carried out. The pressure loss across multiple interactive fittings is lower than that across multiple similar individual fittings, while the percentage decrease is dependent on the configuration and combination of the fittings. This implies that the pressure loss across multiple closely mounted fittings calculated by summing the pressure losses across individual fittings, as provided in the ASHRAE handbook and the CIBSE guide, is overpredicted. The numerical prediction of the pressure losses across multiple fittings using the large-eddy simulation (LES) model shows good agreement with the measured data, suggesting that this model is a useful tool in ductwork design and can help to save experimental resources and improve experimental accuracy and reliability. PMID:24385871

  19. Combined Negative- and Positive-Pressure Ventilation for the Treatment of ARDS

    PubMed Central

    Raymondos, Konstantinos; Ahrens, Jörg; Molitoris, Ulrich

    2015-01-01

    Objective. Tracheal intubation and positive-pressure ventilation as the current standard of care for the adult respiratory distress syndrome (ARDS) seem to have reached their limit in terms of a further relevant reduction of the still very high mortality. Case Presentation. A 75-year-old male patient developed ARDS after abscess drainage with deteriorating oxygenation, despite positive end-expiratory pressure (PEEP) values above 15 cm H2O. We applied external negative-pressure ventilation with a chamber respirator using −33 cm H2O at inspiration and −15 cm H2O at expiration, combined with conventional pressure support using a PEEP of about 8 cm H2O and a pressure support of 4–12 cm H2O. Alveolar infiltrates disappeared rapidly and PaO2/FiO2 values surpassed 300 mmHg after the first application and 500 mmHg after the second. Negative-pressure ventilation was used for 6–18 hours/day over five days. Now, 13 years later, the patient is still alive and has a good quality of life. Conclusion. Using this or similar concepts, not only in intubated patients but also as a noninvasive approach in patients with ARDS, offers new options that may genuinely differ from the present therapeutic approaches and may, therefore, have the potential to decrease the present high mortality from ARDS. PMID:26290758

  20. Dynamics of tidal volume and ventilation heterogeneity under pressure-controlled ventilation during bronchoconstriction: a simulation study

    PubMed Central

    Winkler, Tilo; Harris, R. Scott; Venegas, Jose G.

    2010-01-01

    The difference in effectiveness between volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) on mechanically ventilated patients during bronchoconstriction is not totally clear. PCV is thought to deliver a more uniform distribution of ventilation than VCV, but the delivered tidal volume could be unstable and affected by changes in the degree of constriction. To explore the magnitude of these effects, we ran numerical simulations with both modes of ventilation in a network model of the lung in which we incorporated not only the pressure and flow dynamics along the airways but also the effect of cycling pressures and tissue tethering forces during breathing on the dynamic equilibrium of the airway smooth muscle (ASM) (Venegas et al., Nature 434: 777–782). These simulations provided an illustration of changes in airway radii, the total delivered tidal volume stability, and distribution of ventilation following a transition from VCV to PCV and during progressively increasing ASM activation level. These simulations yielded three major results. First, the ventilation heterogeneity and patchiness in ventilation during steady-state VCV were substantially reduced after the transition to PCV. Second, airway radius, tidal volume, and the distribution of ventilation under severe bronchoconstriction were highly sensitive to the setting of inspiratory pressure selected for PCV and to the degree of activation of the ASM. Third, the dynamic equilibrium of active ASM exposed to cycling forces is the major contributor to these effects. These insights may provide a theoretical framework to guide the selection of ventilation mode, the adjustment of ventilator settings, and the interpretation of clinical observations in mechanically ventilated asthmatic patients. PMID:20671035

  1. Nasal intermittent positive pressure ventilation in preterm infants: Equipment, evidence, and synchronization.

    PubMed

    Owen, Louise S; Manley, Brett J

    2016-06-01

    The use of nasal intermittent positive pressure ventilation (NIPPV) as respiratory support for preterm infants is well established. Evidence from randomized trials indicates that NIPPV is advantageous over continuous positive airway pressure (CPAP) as post-extubation support, albeit with varied outcomes between NIPPV techniques. Randomized data comparing NIPPV with CPAP as primary support, and for the treatment of apnea, are conflicting. Intrepretation of outcomes is limited by the multiple techniques and devices used to generate and deliver NIPPV. This review discusses the potential mechanisms of action of NIPPV in preterm infants, the evidence from clinical trials, and summarizes recommendations for practice. PMID:26922562

  2. Should Airway Pressure Release Ventilation Be the Primary Mode in ARDS?

    PubMed

    Mireles-Cabodevila, Eduardo; Kacmarek, Robert M

    2016-06-01

    Airway pressure release ventilation (APRV) was originally described as a mode to treat lung-injured patients with the goal to maintain a level of airway pressure that would not depress the cardiac function, deliver mechanical breaths without excessive airway pressure, and to allow unrestricted spontaneous ventilation. Indeed, based on its design, APRV has technological features that serve the goals of safety and comfort. Animal studies suggest that APRV leads to alveolar stability and recruitment which result in less lung injury. These features are sought in patients at risk for lung injury or with ARDS. APRV allows unrestricted spontaneous ventilation, which is welcome in the era of less sedation and increased patient mobility (the effects in terms of lung injury remain to be explored). However, we must highlight that the performance of APRV is dependent on the operator-selected settings and the ventilator's performance. The clinician must select the appropriate settings in order to make effective the imputed benefits. This is a challenge when the ventilator's performance is not uniform, and the outcomes depend on high precision settings (very short expiratory time), where small variations can lead to undesired outcomes (de-recruitment or large tidal volumes leading to lung injury). Finally, we do not have evidence that APRV (as originally described) improves relevant clinical outcomes of patients with ARDS. For APRV to become the primary mode of ventilation for ARDS, it will require development of sound protocols and technological enhancements to ensure its performance and safety. For now, APRV does have a greater potential for adversely affecting patient outcome than improving it; unless definitive data are forthcoming demonstrating outcome benefits from the use of APRV in ARDS, there is no reason to consider this approach to ventilatory support. PMID:27235312

  3. A new design for high stability pressure-controlled ventilation for small animal lung imaging

    NASA Astrophysics Data System (ADS)

    Kitchen, M. J.; Habib, A.; Fouras, A.; Dubsky, S.; Lewis, R. A.; Wallace, M. J.; Hooper, S. B.

    2010-02-01

    We have developed a custom-designed ventilator to deliver a stable pressure to the lungs of small animals for use in imaging experiments. Our ventilator was designed with independent pressure vessels to separately control the Peak Inspiratory Pressure (PIP) and Positive End Expiratory Pressure (PEEP) to minimise pressure fluctuations during the ventilation process. The ventilator was computer controlled through a LabVIEW interface, enabling experimental manipulations to be performed remotely whilst simultaneously imaging the lungs in situ. Mechanical ventilation was successfully performed on newborn rabbit pups to assess the most effective ventilation strategies for aerating the lungs at birth. Highly stable pressures enabled reliable respiratory gated acquisition of projection radiographs and a stable prolonged (15 minute) breath-hold for high-resolution computed tomography of deceased rabbit pups at different lung volumes.

  4. 30 CFR 18.28 - Devices for pressure relief, ventilation, or drainage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Devices for pressure relief, ventilation, or... Construction and Design Requirements § 18.28 Devices for pressure relief, ventilation, or drainage. (a) Devices... metal will prevent discharge of flame in explosion tests. (b) Devices for pressure relief,...

  5. Transdiaphragmatic pressure in quadriplegic individuals ventilated by diaphragmatic pacemaker.

    PubMed Central

    Garrido-García, H.; Martín-Escribano, P.; Palomera-Frade, J.; Arroyo, O.; Alonso-Calderón, J. L.; Mazaira-Alvarez, J.

    1996-01-01

    BACKGROUND: Electrophrenic pacing can be used in the management of ventilatory failure in quadriplegic patients. A study was undertaken to determine the pattern of transdiaphragmatic pressure (PDI) during the conditioning phase of electrophrenic pacing to see if it had a possible role in optimising the process of conditioning. METHODS: The tidal volume (TV) and PDI were measured in a group of six quadriplegic patients commencing ventilation by low frequency pulse stimulation (7-10 Hz) and low respiratory rate stimulation (< 10 breaths/min). RESULTS: Tidal volume increased between baseline and month 1 (4.33 ml/kg, p < 0.001) and between months 1 and 2 (3.00 ml/kg, p < 0.05) and then stabilised. PDI was higher during bilateral diaphragmatic pacing (mean (SD) 1.73 (0.30) kPa) than with either left (1.15 (0.34) kPa) or right (0.86 (0.37) kPa) unilateral pacing. PDI varied throughout the observation period, probably by interaction between recovery of the diaphragmatic fibres and the pacing regimen. CONCLUSIONS: Patients with quadriplegia due to high spinal injury can be maintained with ventilation by continuous electrophrenic pacing. The control criteria used in this study for pacing were tidal volume and the patient's tolerance, and the PDI measurement did not contribute any additional information to help with managing the conditioning process. PMID:8733497

  6. Airway Pressure Release Ventilation and High-Frequency Oscillatory Ventilation: Potential Strategies to Treat Severe Hypoxemia and Prevent Ventilator-Induced Lung Injury.

    PubMed

    Facchin, Francesca; Fan, Eddy

    2015-10-01

    Although lifesaving, mechanical ventilation can itself be responsible for damage to lung parenchyma. This ventilator-induced lung injury is especially observed in already injured lungs of patients with ARDS. New ventilatory approaches are needed to safely treat patients with ARDS, and recent studies have suggested the potential utility of open-lung strategies. Airway pressure release ventilation (APRV) and high-frequency oscillatory ventilation (HFOV) are 2 different open-lung strategies that have been proposed to treat refractory hypoxemic respiratory failure while preventing ventilator-induced lung injury. APRV provides increased airway pressure as a potential recruitment mechanism and allows spontaneous breathing, with the potential benefits of decreased sedation, shorter duration of mechanical ventilation, and improvement in cardiac performance. HFOV delivers very small tidal volumes, to prevent volutrauma, at a constant (relatively high) mean airway pressure, thus avoiding atelectrauma. Despite their theoretical benefits, the utility of APRV and HFOV remains unproven and controversial for the routine treatment of ARDS in adult patients. This review is focused on the theoretical and practical aspects of APRV and HFOV, provides an overview of the current evidence, and addresses their possible use in the treatment of ARDS. PMID:26405188

  7. Timing positive-pressure ventilation during chest compression: the key to improving the thoracic pump?

    PubMed

    Chalkias, Athanasios; Xanthos, Theodoros

    2015-02-01

    Given the importance of increased coronary and cerebral perfusion pressure during cardiopulmonary resuscitation, the recommendation of limiting tidal volume and ventilation rate to 10 per minute in order not to inhibit venous return seems to be correct. However, although the resuscitation community believes that positive-pressure ventilation during cardiopulmonary resuscitation is bad for the circulation, proper timing of compression and ventilation may actually improve the circulation. PMID:24381094

  8. Can Selection of Mechanical Ventilation Mode Prevent Increased Intra-Abdominal Pressure in Patients Admitted to the Intensive Care Unit?

    PubMed Central

    Rafiei, Mohammad Reza; Aghadavoudi, Omid; Shekarchi, Babak; Sajjadi, Seyed Sajed; Masoudifar, Mehrdad

    2013-01-01

    Background: Increased intra-abdominal pressure (IAP) results in dysfunction of vital organs. The aim of the present study was to evaluate the effect of mechanical ventilation mode on IAP. Methods: In a cohort study, a total of 60 patients aged 20-70 years who were admitted to the ICU and underwent mechanical ventilation were recruited. Mechanical ventilation included one of the three modes: Biphasic positive airway pressure (BIPAP) group, synchronize intermittent mandatory ventilation (SIMV) group, or continuous positive airway pressure (CPAP) group. For each patient, mechanical ventilation mode and its parameters, blood pressure, SpO2, and status of tube feeding and IAP were recorded. Results: Our findings indicate that the study groups were not significantly different in terms of anthropometric characteristics including age (64.5 ± 4, P = 0.1), gender (male/female 31/29, P = 0.63), and body mass index (24 ± 1.2, P = 0.11). Increase IAP was related to the type of respiratory mode with the more increased IAP observed in SIMV mode, followed by BIPAP and CPAP modes (P = 0.01). There were significant correlations between increased IAP and respiratory variables including respiratory rate, pressure support ventilation, and inspiratory pressure (P < 0.05). Tube feeding tolerance through NG-tube was lower in SIMV group, followed by BIPAP and CPAP groups (P < 0.05). Conclusions: There is a significant relationship between respiratory modes and IAP; therefore, it is better to utilize those types of mechanical ventilation like CPAP and BIPAP mode in patients who are prone to Intra-abdominal hypertension. PMID:23930166

  9. Response of respiratory motor output to varying pressure in mechanically ventilated patients.

    PubMed

    Xirouhaki, N; Kondili, E; Mitrouska, I; Siafakas, N; Georgopoulos, D

    1999-09-01

    It has been shown in mechanically ventilated patients that pressure support (PS) unloads the respiratory muscles in a graded fashion depending on the PS level. The downregulation of respiratory muscles could be mediated through chemical or load-related reflex feedback. To test this hypothesis, 8 patients with acute lung injury mechanically ventilated on PS mode (baseline PS) were studied. In Protocol A, PS was randomly decreased or increased by at least 5 cmH2O for two breaths. During this time, which is shorter than circulation delay, only changes in load-related reflex feedback were operating. Sixty trials where PS increased (high PS) for two breaths and 62 trials where PS decreased (low PS), also for two breaths were analysed. Thereafter, the patients were assigned randomly to baseline, low or high PS and ventilated in each level for 30 min (Protocol B). The last 2 min of each period were analysed. Respiratory motor output was assessed by total pressure generated by the respiratory muscles (Pmus), computed from oesophageal pressure (Poes). In Protocol A, alteration in PS caused significant changes in tidal volume (VT) without any effect on Pmus waveform except for neural expiratory time (ntE). ntE increased significantly with increasing PS. In Protocol B, Pmus was significantly down-regulated with increasing PS. Carbon dioxide tension in arterial blood (Pa,CO2) measured at the end of each period increased with decreasing PS. There was not any further alteration in ntE beyond that observed in Protocol A. These results indicate that the effect of load-related reflex on respiratory motor output is limited to timing. The downregulation of pressure generated by the respiratory muscles with steady-state increase in pressure support is due to a slow feedback system, which is probably chemical in nature. PMID:10543268

  10. [The numerical simulation of the internal flow field inside the pressure generator of a continuous positive airway pressure ventilator].

    PubMed

    Cheng, Yunzhang; Zhu, Lihua; Zhang, Weiguo; Wu, Wenquan

    2011-12-01

    The problem of noise in ventilator has always been an important topic to study in the development of the ventilator. A great number of data are showing that there are still large gaps of research and application levels in noise control of the ventilator between China and some more advanced foreign countries. In this study, with cooperation of the Shanghai Medical Equipment Limited Liability Company, we used the computational fluid dynamics (CFD), software FLUENT, adopted the standard k-epsilon turbulence model and the SIMPLE algorithm to simulate the inner flow field of the continuous positive airway pressure (CPAP) ventilator's pressure generator. After a detailed analysis, we figured out that there are several deficiencies in this ventilator, like local reflow in volute, uneven velocity distribution and local negative pressure in inlet of the impeller, which easily lead to noise and affect the ventilator's performances. So, it needs to be improved to a certain extent. PMID:22295700

  11. The 30-year evolution of airway pressure release ventilation (APRV).

    PubMed

    Jain, Sumeet V; Kollisch-Singule, Michaela; Sadowitz, Benjamin; Dombert, Luke; Satalin, Josh; Andrews, Penny; Gatto, Louis A; Nieman, Gary F; Habashi, Nader M

    2016-12-01

    Airway pressure release ventilation (APRV) was first described in 1987 and defined as continuous positive airway pressure (CPAP) with a brief release while allowing the patient to spontaneously breathe throughout the respiratory cycle. The current understanding of the optimal strategy to minimize ventilator-induced lung injury is to "open the lung and keep it open". APRV should be ideal for this strategy with the prolonged CPAP duration recruiting the lung and the minimal release duration preventing lung collapse. However, APRV is inconsistently defined with significant variation in the settings used in experimental studies and in clinical practice. The goal of this review was to analyze the published literature and determine APRV efficacy as a lung-protective strategy. We reviewed all original articles in which the authors stated that APRV was used. The primary analysis was to correlate APRV settings with physiologic and clinical outcomes. Results showed that there was tremendous variation in settings that were all defined as APRV, particularly CPAP and release phase duration and the parameters used to guide these settings. Thus, it was impossible to assess efficacy of a single strategy since almost none of the APRV settings were identical. Therefore, we divided all APRV studies divided into two basic categories: (1) fixed-setting APRV (F-APRV) in which the release phase is set and left constant; and (2) personalized-APRV (P-APRV) in which the release phase is set based on changes in lung mechanics using the slope of the expiratory flow curve. Results showed that in no study was there a statistically significant worse outcome with APRV, regardless of the settings (F-ARPV or P-APRV). Multiple studies demonstrated that P-APRV stabilizes alveoli and reduces the incidence of acute respiratory distress syndrome (ARDS) in clinically relevant animal models and in trauma patients. In conclusion, over the 30 years since the mode's inception there have been no strict

  12. High frequency jet ventilation and intermittent positive pressure ventilation. Effect of cerebral blood flow in patients after open heart surgery

    SciTech Connect

    Pittet, J.F.; Forster, A.; Suter, P.M. )

    1990-02-01

    Attenuation of ventilator-synchronous pressure fluctuations of intracranial pressure has been demonstrated during high frequency ventilation in animal and human studies, but the consequences of this effect on cerebral blood flow have not been investigated in man. We compared the effects of high frequency jet ventilation and intermittent positive pressure ventilation on CBF in 24 patients investigated three hours after completion of open-heart surgery. The patients were investigated during three consecutive periods with standard sedation (morphine, pancuronium): a. IPPV; b. HFJV; c. IPPV. Partial pressure of arterial CO{sub 2} (PaCO{sub 2}: 4.5-5.5 kPa) and rectal temperature (35.5 to 37.5{degree}C) were maintained constant during the study. The CBF was measured by intravenous {sup 133}Xe washout technique. The following variables were derived from the cerebral clearance of {sup 133}Xe: the rapid compartment flow, the initial slope index, ie, a combination of the rapid and the slow compartment flows, and the ratio of fast compartment flow over total CBF (FF). Compared to IPPV, HFJV applied to result in the same mean airway pressure did not produce any change in pulmonary gas exchange, mean systemic arterial pressure, and cardiac index. Similarly, CBF was not significantly altered by HFJV. However, important variations of CBF values were observed in three patients, although the classic main determinants of CBF (PaCO{sub 2}, cerebral perfusion pressure, Paw, temperature) remained unchanged. Our results suggest that in patients with normal systemic hemodynamics, the effects of HFJV and IPPV on CBF are comparable at identical levels of mean airway pressure.

  13. Changes in intrathoracic pressures induced by positive end-expiratory pressure ventilation after cardiac surgical procedures.

    PubMed

    Bonnet, F; Fischler, M; Dubois, C L; Brodaty, D; Pluskwa, F; Guilmet, D; Vourc'h, G

    1986-10-01

    The consequences of controlled ventilation with positive end-expiratory pressure (PEEP) were studied, after cardiac surgical procedures, in two groups of patients supposed to have different lung and chest wall mechanical properties. The first group included 6 patients who had undergone coronary artery graft surgical procedures (CGS). The second group included 5 patients who had undergone a mitral valve replacement (MVR). Postoperatively, static lung and chest wall compliance was measured by stepwise inflation and deflation of the thorax. Esophageal, pericardial, and pleural pressures were then measured, and cardiac output was determined while PEEP was increased from 0 to 20 cm H2O. Lung and chest wall compliance values sharply decreased in MVR patients. This accounts for the lower values for pleural and pericardial pressures in this group than in the CGS patient group, but the transmission of airway pressure was identical in the two groups when PEEP was increased. The decrease in cardiac output induced by PEEP was similar in the two groups. The results suggest that the opposing influences of lung and chest wall compliance on airway pressure transmission could at least partly explain the hemodynamic effects of PEEP in patients in whom the mechanical properties of the lung and thorax are impaired. PEEP ventilation should be used cautiously in patients suspected of having thoracic rigidity. PMID:3532981

  14. Successful management of drug-induced hypercapnic acidosis with naloxone and noninvasive positive pressure ventilation.

    PubMed

    Agrafiotis, Michalis; Tryfon, Stavros; Siopi, Demetra; Chassapidou, Georgia; Galanou, Artemis; Tsara, Venetia

    2015-02-01

    A 74-year-old man was referred to our hospital due to deteriorating level of consciousness and desaturation. His Glasgow Coma Scale was 6, and his pupils were constricted but responded to light. Chest radiograph was negative for significant findings. Arterial blood gas evaluation on supplemental oxygen revealed severe acute on chronic respiratory acidosis: pH 7.15; PCO2, 133 mm Hg; PO2,64 mm Hg; and HCO3, 31 mmol/L. He regained full consciousness (Glasgow Coma Scale, 15) after receiving a 0.4 mg dose of naloxone, but because of persistent severe respiratory acidosis (pH 7.21; PCO2, 105 mm Hg), he was immediately commenced on noninvasive positive pressure ventilation (NIV) displaying a remarkable improvement in arterial blood gas values within the next few hours. However, in the days that followed, he remained dependent on NIV, and he was finally discharged on a home mechanical ventilation prescription. In cases of drug-induced respiratory depression, NIV should be regarded as an acceptable treatment, as it can provide ventilatory support without the increased risks associated with invasive mechanical ventilation. PMID:25176564

  15. The Effect of Pressure-Controlled Ventilation and Volume-Controlled Ventilation in Prone Position on Pulmonary Mechanics and Inflammatory Markers.

    PubMed

    Şenay, Hasan; Sıvacı, Remziye; Kokulu, Serdar; Koca, Buğra; Bakı, Elif Doğan; Ela, Yüksel

    2016-08-01

    The aim of this present study is to compare the effect of pressure-controlled ventilation and volume-controlled ventilation on pulmonary mechanics and inflammatory markers in prone position. The study included 41 patients undergoing to vertebrae surgery. The patients were randomized into two groups: Group 1 received volume-controlled ventilation, while group 2 received pressure-controlled ventilation. The demographic data, pulmonary mechanics, the inflammatory marker levels just after the induction of anesthetics, at the 6th and 12th hours, and gas analysis from arterial blood samples taken at the beginning and the 30th minute were recorded. The inflammatory marker levels increased in both groups, without any significant difference among groups. Peak inspiratory pressure level was higher in the volume-controlled ventilation group. This study revealed that there is no difference regarding inflammatory marker levels between volume- and pressure-controlled ventilation. PMID:27221140

  16. Hemodynamic Effects of Nasal Intermittent Positive Pressure Ventilation in Preterm Infants

    PubMed Central

    Chang, Hung-Yang; Cheng, Kun-Shan; Lung, Hou-Ling; Li, Sung-Tse; Lin, Chien-Yu; Lee, Hung-Chang; Lee, Ching-Hsiao; Hung, Hsiao-Fang

    2016-01-01

    Abstract Nasal intermittent positive pressure ventilation (NIPPV) and nasal continuous positive airway pressure (NCPAP) have proven to be effective modes of noninvasive respiratory support in preterm infants. Although they are increasingly used in neonatal intensive care, their hemodynamic consequences have not been fully evaluated. The aim of this study was to investigate the hemodynamic changes between NIPPV and NCPAP in preterm infants. This prospective observational study enrolled clinically stable preterm infants requiring respiratory support received NCPAP and nonsynchronized NIPPV at 40/minute for 30 minutes each, in random order. Cardiac function and cerebral hemodynamics were assessed by ultrasonography after each study period. The patients continued the study ventilation during measurements. Twenty infants with a mean gestational age of 27 weeks (range, 25–32 weeks) and birth weight of 974 g were examined at a median postnatal age of 20 days (range, 9–28 days). There were no significant differences between the NCPAP and NIPPV groups in right (302 vs 292 mL/kg/min, respectively) and left ventricular output (310 vs 319 mL/kg/min, respectively), superior vena cava flow (103 vs 111 mL/kg/min, respectively), or anterior cerebral artery flow velocity. NIPPV did not have a significant effect on the hemodynamics of stable preterm infants. Future studies assessing the effect of NIPPV on circulation should focus on less stable and very preterm infants. PMID:26871833

  17. Hemodynamic Effects of Nasal Intermittent Positive Pressure Ventilation in Preterm Infants.

    PubMed

    Chang, Hung-Yang; Cheng, Kun-Shan; Lung, Hou-Ling; Li, Sung-Tse; Lin, Chien-Yu; Lee, Hung-Chang; Lee, Ching-Hsiao; Hung, Hsiao-Fang

    2016-02-01

    Nasal intermittent positive pressure ventilation (NIPPV) and nasal continuous positive airway pressure (NCPAP) have proven to be effective modes of noninvasive respiratory support in preterm infants. Although they are increasingly used in neonatal intensive care, their hemodynamic consequences have not been fully evaluated. The aim of this study was to investigate the hemodynamic changes between NIPPV and NCPAP in preterm infants.This prospective observational study enrolled clinically stable preterm infants requiring respiratory support received NCPAP and nonsynchronized NIPPV at 40/minute for 30 minutes each, in random order. Cardiac function and cerebral hemodynamics were assessed by ultrasonography after each study period. The patients continued the study ventilation during measurements.Twenty infants with a mean gestational age of 27 weeks (range, 25-32 weeks) and birth weight of 974 g were examined at a median postnatal age of 20 days (range, 9-28 days). There were no significant differences between the NCPAP and NIPPV groups in right (302 vs 292 mL/kg/min, respectively) and left ventricular output (310 vs 319 mL/kg/min, respectively), superior vena cava flow (103 vs 111 mL/kg/min, respectively), or anterior cerebral artery flow velocity.NIPPV did not have a significant effect on the hemodynamics of stable preterm infants. Future studies assessing the effect of NIPPV on circulation should focus on less stable and very preterm infants. PMID:26871833

  18. Heterogeneity of cerebral vasoreactivity in preterm infants supported by mechanical ventilation

    SciTech Connect

    Pryds, O.; Greisen, G.; Lou, H.; Friis-Hansen, B. )

    1989-10-01

    The reaction of cerebral blood flow to acute changes in arterial carbon dioxide pressure (PaCO2) and mean arterial blood pressure was determined in 57 preterm infants supported by mechanical ventilation (mean gestational age 30.1 weeks) during the first 48 hours of life. All infants had normal brain sonograms at the time of the investigation. In each infant, global cerebral blood flow was determined by xenon-133 clearance two to five times within a few hours at different levels of PaCO2. Changes in PaCO2 followed adjustments of the ventilator settings. Arterial oxygen pressure was intended to be kept constant, and mean arterial blood pressure fluctuated spontaneously between measurements. The data were analyzed by stepwise multiple regression, with changes in global cerebral blood flow, PaCO2, mean arterial blood pressure, and postnatal age or intracranial hemorrhage used as variables. In infants with persistently normal brain sonograms, the global cerebral blood flow-carbon dioxide reactivity was markedly lower during the first day of life (mean 11.2% to 11.8%/kPa PaCO2) compared with the second day of life (mean 32.6/kPa PaCO2), and pressure-flow autoregulation was preserved. Similarly, global cerebral blood flow-carbon dioxide reactivity and pressure-flow autoregulation were present in infants in whom mild intracranial hemorrhage developed after the study. In contrast, global cerebral blood flow reactivity to changes in PaCO2 and mean arterial blood pressure was absent in infants in whom ultrasonographic signs of severe intracranial hemorrhage subsequently developed. These infants also had about 20% lower global cerebral blood flow before hemorrhage, in comparison with infants whose sonograms were normal, a finding that suggests functional disturbances of cerebral blood flow regulation.

  19. Noninvasive Positive Pressure Ventilation for Chronic Respiratory Failure Patients With Stable Chronic Obstructive Pulmonary Disease (COPD)

    PubMed Central

    2012-01-01

    Executive Summary In July 2010, the Medical Advisory Secretariat (MAS) began work on a Chronic Obstructive Pulmonary Disease (COPD) evidentiary framework, an evidence-based review of the literature surrounding treatment strategies for patients with COPD. This project emerged from a request by the Health System Strategy Division of the Ministry of Health and Long-Term Care that MAS provide them with an evidentiary platform on the effectiveness and cost-effectiveness of COPD interventions. After an initial review of health technology assessments and systematic reviews of COPD literature, and consultation with experts, MAS identified the following topics for analysis: vaccinations (influenza and pneumococcal), smoking cessation, multidisciplinary care, pulmonary rehabilitation, long-term oxygen therapy, noninvasive positive pressure ventilation for acute and chronic respiratory failure, hospital-at-home for acute exacerbations of COPD, and telehealth (including telemonitoring and telephone support). Evidence-based analyses were prepared for each of these topics. For each technology, an economic analysis was also completed where appropriate. In addition, a review of the qualitative literature on patient, caregiver, and provider perspectives on living and dying with COPD was conducted, as were reviews of the qualitative literature on each of the technologies included in these analyses. The Chronic Obstructive Pulmonary Disease Mega-Analysis series is made up of the following reports, which can be publicly accessed at the MAS website at: http://www.hqontario.ca/en/mas/mas_ohtas_mn.html. Chronic Obstructive Pulmonary Disease (COPD) Evidentiary Framework Influenza and Pneumococcal Vaccinations for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis Smoking Cessation for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis Community-Based Multidisciplinary Care for Patients With Stable Chronic Obstructive

  20. Inhibitory Effect of Nasal Intermittent Positive Pressure Ventilation on Gastroesophageal Reflux.

    PubMed

    Cantin, Danny; Djeddi, Djamal; Carrière, Vincent; Samson, Nathalie; Nault, Stéphanie; Jia, Wan Lu; Beck, Jennifer; Praud, Jean-Paul

    2016-01-01

    Non-invasive intermittent positive pressure ventilation can lead to esophageal insufflations and in turn to gastric distension. The fact that the latter induces transient relaxation of the lower esophageal sphincter implies that it may increase gastroesophageal refluxes. We previously reported that nasal Pressure Support Ventilation (nPSV), contrary to nasal Neurally-Adjusted Ventilatory Assist (nNAVA), triggers active inspiratory laryngeal closure. This suggests that esophageal insufflations are more frequent in nPSV than in nNAVA. The objectives of the present study were to test the hypotheses that: i) gastroesophageal refluxes are increased during nPSV compared to both control condition and nNAVA; ii) esophageal insufflations occur more frequently during nPSV than nNAVA. Polysomnographic recordings and esophageal multichannel intraluminal impedance pHmetry were performed in nine chronically instrumented newborn lambs to study gastroesophageal refluxes, esophageal insufflations, states of alertness, laryngeal closure and respiration. Recordings were repeated without sedation in control condition, nPSV (15/4 cmH2O) and nNAVA (~ 15/4 cmH2O). The number of gastroesophageal refluxes recorded over six hours, expressed as median (interquartile range), decreased during both nPSV (1 (0, 3)) and nNAVA [1 (0, 3)] compared to control condition (5 (3, 10)), (p < 0.05). Meanwhile, the esophageal insufflation index did not differ between nPSV (40 (11, 61) h-1) and nNAVA (10 (9, 56) h-1) (p = 0.8). In conclusion, nPSV and nNAVA similarly inhibit gastroesophageal refluxes in healthy newborn lambs at pressures that do not lead to gastric distension. In addition, the occurrence of esophageal insufflations is not significantly different between nPSV and nNAVA. The strong inhibitory effect of nIPPV on gastroesophageal refluxes appears identical to that reported with nasal continuous positive airway pressure. PMID:26785264

  1. Inhibitory Effect of Nasal Intermittent Positive Pressure Ventilation on Gastroesophageal Reflux

    PubMed Central

    Cantin, Danny; Djeddi, Djamal; Carrière, Vincent; Samson, Nathalie; Nault, Stéphanie; Jia, Wan Lu; Beck, Jennifer; Praud, Jean-Paul

    2016-01-01

    Non-invasive intermittent positive pressure ventilation can lead to esophageal insufflations and in turn to gastric distension. The fact that the latter induces transient relaxation of the lower esophageal sphincter implies that it may increase gastroesophageal refluxes. We previously reported that nasal Pressure Support Ventilation (nPSV), contrary to nasal Neurally-Adjusted Ventilatory Assist (nNAVA), triggers active inspiratory laryngeal closure. This suggests that esophageal insufflations are more frequent in nPSV than in nNAVA. The objectives of the present study were to test the hypotheses that: i) gastroesophageal refluxes are increased during nPSV compared to both control condition and nNAVA; ii) esophageal insufflations occur more frequently during nPSV than nNAVA. Polysomnographic recordings and esophageal multichannel intraluminal impedance pHmetry were performed in nine chronically instrumented newborn lambs to study gastroesophageal refluxes, esophageal insufflations, states of alertness, laryngeal closure and respiration. Recordings were repeated without sedation in control condition, nPSV (15/4 cmH2O) and nNAVA (~ 15/4 cmH2O). The number of gastroesophageal refluxes recorded over six hours, expressed as median (interquartile range), decreased during both nPSV (1 (0, 3)) and nNAVA [1 (0, 3)] compared to control condition (5 (3, 10)), (p < 0.05). Meanwhile, the esophageal insufflation index did not differ between nPSV (40 (11, 61) h-1) and nNAVA (10 (9, 56) h-1) (p = 0.8). In conclusion, nPSV and nNAVA similarly inhibit gastroesophageal refluxes in healthy newborn lambs at pressures that do not lead to gastric distension. In addition, the occurrence of esophageal insufflations is not significantly different between nPSV and nNAVA. The strong inhibitory effect of nIPPV on gastroesophageal refluxes appears identical to that reported with nasal continuous positive airway pressure. PMID:26785264

  2. Optimization of ventilator setting by flow and pressure waveforms analysis during noninvasive ventilation for acute exacerbations of COPD: a multicentric randomized controlled trial

    PubMed Central

    2011-01-01

    Introduction The analysis of flow and pressure waveforms generated by ventilators can be useful in the optimization of patient-ventilator interactions, notably in chronic obstructive pulmonary disease (COPD) patients. To date, however, a real clinical benefit of this approach has not been proven. Methods The aim of the present randomized, multi-centric, controlled study was to compare optimized ventilation, driven by the analysis of flow and pressure waveforms, to standard ventilation (same physician, same initial ventilator setting, same time spent at the bedside while the ventilator screen was obscured with numerical data always available). The primary aim was the rate of pH normalization at two hours, while secondary aims were changes in PaCO2, respiratory rate and the patient's tolerance to ventilation (all parameters evaluated at baseline, 30, 120, 360 minutes and 24 hours after the beginning of ventilation). Seventy patients (35 for each group) with acute exacerbation of COPD were enrolled. Results Optimized ventilation led to a more rapid normalization of pH at two hours (51 vs. 26% of patients), to a significant improvement of the patient's tolerance to ventilation at two hours, and to a higher decrease of PaCO2 at two and six hours. Optimized ventilation induced physicians to use higher levels of external positive end-expiratory pressure, more sensitive inspiratory triggers and a faster speed of pressurization. Conclusions The analysis of the waveforms generated by ventilators has a significant positive effect on physiological and patient-centered outcomes during acute exacerbation of COPD. The acquisition of specific skills in this field should be encouraged. Trial registration ClinicalTrials.gov NCT01291303. PMID:22115190

  3. Newer nonconventional modes of mechanical ventilation.

    PubMed

    Singh, Preet Mohinder; Borle, Anuradha; Trikha, Anjan

    2014-07-01

    The conventional modes of ventilation suffer many limitations. Although they are popularly used and are well-understood, often they fail to match the patient-based requirements. Over the years, many small modifications in ventilators have been incorporated to improve patient outcome. The ventilators of newer generation respond to patient's demands by additional feedback systems. In this review, we discuss the popular newer modes of ventilation that have been accepted in to clinical practice. Various intensive care units over the world have found these modes to improve patient ventilator synchrony, decrease ventilator days and improve patient safety. The various modes discusses in this review are: Dual control modes (volume assured pressure support, volume support), Adaptive support ventilation, proportional assist ventilation, mandatory minute ventilation, Bi-level airway pressure release ventilation, (BiPAP), neurally adjusted ventilatory assist and NeoGanesh. Their working principles with their advantages and clinical limitations are discussed in brief. PMID:25114434

  4. Newer nonconventional modes of mechanical ventilation

    PubMed Central

    Singh, Preet Mohinder; Borle, Anuradha; Trikha, Anjan

    2014-01-01

    The conventional modes of ventilation suffer many limitations. Although they are popularly used and are well-understood, often they fail to match the patient-based requirements. Over the years, many small modifications in ventilators have been incorporated to improve patient outcome. The ventilators of newer generation respond to patient's demands by additional feedback systems. In this review, we discuss the popular newer modes of ventilation that have been accepted in to clinical practice. Various intensive care units over the world have found these modes to improve patient ventilator synchrony, decrease ventilator days and improve patient safety. The various modes discusses in this review are: Dual control modes (volume assured pressure support, volume support), Adaptive support ventilation, proportional assist ventilation, mandatory minute ventilation, Bi-level airway pressure release ventilation, (BiPAP), neurally adjusted ventilatory assist and NeoGanesh. Their working principles with their advantages and clinical limitations are discussed in brief. PMID:25114434

  5. [Long-term effects of home mechanical ventilation with positive pressure using a nasal mask].

    PubMed

    Escarrabill, J; Estopà, R; Robert, D; Casolivé, V; Manresa, F

    1991-10-01

    Home mechanical ventilation (HMV) is an efficient alternative in the treatment of patients with chronic respiratory failure secondary to restrictive mechanical disorders (neuromuscular disease, such as Duchenne's disease, thorax deformities due to kyphoscoliosis or tuberculosis sequelae). The case of a patient with severe kyphoscoliosis in the phase of chronic respiratory failure (PaO2 34 mmHg and PaCO2 61 mmHg, breathing ambient air) is presented in which, following the failure of negative pressure mechanical ventilation ("poncho"), positive pressure ventilation was tested with a silicon made-to-measure nasal mask as the access via. Adaptation to HMV was good with the patient using the ventilation nightly. Following 12 months of treatment the patient is able to carry out everyday activities and arterial gasometry breathing ambient air is PaO2 77 mmHg and PaCO2 43 mmHg. PMID:1961049

  6. Ventilator-associated lung injury during assisted mechanical ventilation.

    PubMed

    Saddy, Felipe; Sutherasan, Yuda; Rocco, Patricia R M; Pelosi, Paolo

    2014-08-01

    Assisted mechanical ventilation (MV) may be a favorable alternative to controlled MV at the early phase of acute respiratory distress syndrome (ARDS), since it requires less sedation, no paralysis and is associated with less hemodynamic deterioration, better distal organ perfusion, and lung protection, thus reducing the risk of ventilator-associated lung injury (VALI). In the present review, we discuss VALI in relation to assisted MV strategies, such as volume assist-control ventilation, pressure assist-control ventilation, pressure support ventilation (PSV), airway pressure release ventilation (APRV), APRV with PSV, proportional assist ventilation (PAV), noisy ventilation, and neurally adjusted ventilatory assistance (NAVA). In summary, we suggest that assisted MV can be used in ARDS patients in the following situations: (1) Pao(2)/Fio(2) >150 mm Hg and positive end-expiratory pressure ≥ 5 cm H(2)O and (2) with modalities of pressure-targeted and time-cycled breaths including more or less spontaneous or supported breaths (A-PCV [assisted pressure-controlled ventilation] or APRV). Furthermore, during assisted MV, the following parameters should be monitored: inspiratory drive, transpulmonary pressure, and tidal volume (6 mL/kg). Further studies are required to determine the impact of novel modalities of assisted ventilation such as PAV, noisy pressure support, and NAVA on VALI. PMID:25105820

  7. Management of Ventilatory Insufficiency in Neuromuscular Patients Using Mechanical Ventilator Supported by the Korean Government

    PubMed Central

    2016-01-01

    Since 2001, financial support has been provided for all patients with neuromuscular disease (NMD) who require ventilatory support due to the paralysis of respiratory muscles in Korea. The purpose of this study was to identify ventilator usage status and appropriateness in these patients. We included 992 subjects with rare and incurable NMD registered for ventilator rental fee support. From 21 February 2011 to 17 January 2013, ventilator usage information, regular follow-up observation, and symptoms of chronic hypoventilation were surveyed by phone. Home visits were conducted for patients judged by an expert medical team to require medical examination. Abnormal ventilatory status was assessed by respiratory evaluation. Chronic respiratory insufficiency symptoms were reported by 169 of 992 subjects (17%), while 565 subjects (57%) did not receive regular respiratory evaluation. Ventilatory status was abnormal in 102 of 343 home-visit subjects (29.7%). Although 556 subjects (56%) reported 24-hour ventilator use, only 458 (46%) had an oxygen saturation monitoring device, and 305 (31%) performed an airstacking exercise. A management system that integrates ventilator usage monitoring, counselling and advice, and home visits for patients who receive ventilator support could improve the efficiency of the ventilator support project. PMID:27247509

  8. Management of Ventilatory Insufficiency in Neuromuscular Patients Using Mechanical Ventilator Supported by the Korean Government.

    PubMed

    Kang, Seong-Woong; Choi, Won Ah; Cho, Han Eol; Lee, Jang Woo; Park, Jung Hyun

    2016-06-01

    Since 2001, financial support has been provided for all patients with neuromuscular disease (NMD) who require ventilatory support due to the paralysis of respiratory muscles in Korea. The purpose of this study was to identify ventilator usage status and appropriateness in these patients. We included 992 subjects with rare and incurable NMD registered for ventilator rental fee support. From 21 February 2011 to 17 January 2013, ventilator usage information, regular follow-up observation, and symptoms of chronic hypoventilation were surveyed by phone. Home visits were conducted for patients judged by an expert medical team to require medical examination. Abnormal ventilatory status was assessed by respiratory evaluation. Chronic respiratory insufficiency symptoms were reported by 169 of 992 subjects (17%), while 565 subjects (57%) did not receive regular respiratory evaluation. Ventilatory status was abnormal in 102 of 343 home-visit subjects (29.7%). Although 556 subjects (56%) reported 24-hour ventilator use, only 458 (46%) had an oxygen saturation monitoring device, and 305 (31%) performed an airstacking exercise. A management system that integrates ventilator usage monitoring, counselling and advice, and home visits for patients who receive ventilator support could improve the efficiency of the ventilator support project. PMID:27247509

  9. Development of a lightweight portable ventilator for far-forward battlefield combat casualty support

    NASA Astrophysics Data System (ADS)

    Cutchis, Protagoras N.; Smith, Dexter G.; Ko, Harvey W.; Wiesmann, William P.; Pranger, L. Alex

    1999-07-01

    Immediate medical provision substantially reduces the number of fatalities sustained during military operations. However, the shift from large-scale regional conflicts to smaller peacekeeping and humanitarian missions has reduced the military medical support infrastructure. Civilian emergency medical services have long emphasized the 'golden hour' during which a patient must receive definitive medical attention. Without on-scene medical support, injured soldiers must be transported significant distances before receiving advanced medical care, and rapid transport to a medical facility is not always a viable option. Technological solutions enable military medics to deliver advanced medical care on the battlefield. We report here on the development of a small lightweight portable respirator for the treatment of far- forward battlefield casualties. The Far Forward Life Support System (FFLSS) utilizes a combination of COTS (commercial off the shelf) components and custom designed systems to provide ventilatory support to injured combatants. It also incorporates a small IV fluid pump and IV fluids for resuscitation. A microcompressor control system monitors both system performance and patient parameters for system control. Telemetry to a pager-like device worn by the front line medic alerts of any anomalies in ventilator or patient parameters, which will add greatly to triage decisions and resource management. Novel elements of the FLSS design include oxygen generation, low-pressure air generation, available patient suction, and the absence of any high pressure air cylinders. A prototype developed for animal testing will be described in detail as well as further design requirements for the human rated prototype.

  10. A mathematical model approach quantifying patients' response to changes in mechanical ventilation: evaluation in volume support.

    PubMed

    Larraza, S; Dey, N; Karbing, D S; Jensen, J B; Nygaard, M; Winding, R; Rees, S E

    2015-04-01

    This paper presents a mathematical model-approach to describe and quantify patient-response to changes in ventilator support. The approach accounts for changes in metabolism (V̇O2, V̇CO2) and serial dead space (VD), and integrates six physiological models of: pulmonary gas-exchange; acid-base chemistry of blood, and cerebrospinal fluid; chemoreflex respiratory-drive; ventilation; and degree of patients' respiratory muscle-response. The approach was evaluated with data from 12 patients on volume support ventilation mode. The models were tuned to baseline measurements of respiratory gases, ventilation, arterial acid-base status, and metabolism. Clinical measurements and model simulated values were compared at five ventilator support levels. The models were shown to adequately describe data in all patients (χ(2), p > 0.2) accounting for changes in V̇CO2, VD and inadequate respiratory muscle-response. F-ratio tests showed that this approach provides a significantly better (p < 0.001) description of measured data than: (a) a similar model omitting the degree of respiratory muscle-response; and (b) a model of constant alveolar ventilation. The approach may help predict patients' response to changes in ventilator support at the bedside. PMID:25686673

  11. Does the use of primary continuous positive airway pressure reduce the need for intubation and mechanical ventilation in infants ≤32 weeks’ gestation?

    PubMed Central

    Yee, Wendy H; Scotland, Jeanne; Pham, Yung; Finch, Robert

    2011-01-01

    BACKGROUND: Ventilator-induced lung injury is a recognized risk factor for bronchopulmonary dysplasia. OBJECTIVE: To determine whether primary continuous positive airway pressure (CPAP), defined as CPAP without previous endotracheal intubation for any indication, can reduce the need for intubation and mechanical ventilation in infants born at ≤32 weeks’ gestational age. METHODS: The literature was reviewed using the methodology for systematic reviews for the Consensus on Resuscitation Science adapted from the American Heart Association’s International Liaison Committee on Resuscitation. RESULTS: Fourteen studies were reviewed. Eleven studies provided varying degrees of supportive evidence (level of evidence 3 to 4) that the use of primary CPAP can reduce the need for intubation and mechanical ventilation. CONCLUSION: The use of CPAP as a primary intervention and mode of respiratory support is an option for infants ≤32 weeks’ gestation, but avoidance of intubation and mechanical ventilation is more likely in mature infants >27 weeks’ gestation. PMID:23204903

  12. PATIENT-VENTILATION ASYNCHRONY CAUSING NEGATIVE PRESSURE PULMONARY EDEMA IN AN INTUBATED OBESE PATIENT.

    PubMed

    Siddik-Sayyid, Sahar M; AlFahel, Waseem; El-Khatib, Mohamad F

    2016-02-01

    Negative pressure pulmonary edema is a potentially life-threatening condition that may occur when a large negative intrathoracic pressure is generated against a 'physically' obstructed upper airway during emergence from anesthesia. We report a 35 year old male patient who is morbidly obese and undergoing laparoscopic gastric bypass who developed negative pressure pulmonary edema without any evidence of a 'physical' upper airway obstruction. In our patient, the negative pressure pulmonary edema occurred after complete reversal of neuromuscular blockade and during manual positive pressure ventilation with the endotracheal tube still in place and in the presence of an oral airway. Since the patient was still intubated and had an airway in place with no possibility for physical obstruction, we speculate that the occurrence of the negative pressure pulmonary edema was mainly due to a 'functional' obstruction secondary to the severe patient-ventilation asynchrony that ensued upon reversal of the neuromuscular blockade. PMID:27382824

  13. Leakage Characteristics of Dual-Cannula Fenestrated Tracheostomy Tubes during Positive Pressure Ventilation: A Bench Study.

    PubMed

    Berlet, Thomas; Marchon, Mathias

    2016-01-01

    This study compared the leakage characteristics of different types of dual-cannula fenestrated tracheostomy tubes during positive pressure ventilation. Fenestrated Portex® Blue Line Ultra®, TRACOE® twist, or Rüsch® Traceofix® tracheostomy tubes equipped with nonfenestrated inner cannulas were tested in a tracheostomy-lung simulator. Transfenestration pressures and transfenestration leakage rates were measured during positive pressure ventilation. The impact of different ventilation modes, airway pressures, temperatures, and simulated static lung compliance settings on leakage characteristics was assessed. We observed substantial differences in transfenestration pressures and transfenestration leakage rates. The leakage rates of the best performing tubes were <3.5% of the delivered minute volume. At body temperature, the leakage rates of these tracheostomy tubes were <1%. The tracheal tube design was the main factor that determined the leakage characteristics. Careful tracheostomy tube selection permits the use of fenestrated tracheostomy tubes in patients receiving positive pressure ventilation immediately after stoma formation and minimises the risk of complications caused by transfenestration gas leakage, for example, subcutaneous emphysema. PMID:27073395

  14. Leakage Characteristics of Dual-Cannula Fenestrated Tracheostomy Tubes during Positive Pressure Ventilation: A Bench Study

    PubMed Central

    2016-01-01

    This study compared the leakage characteristics of different types of dual-cannula fenestrated tracheostomy tubes during positive pressure ventilation. Fenestrated Portex® Blue Line Ultra®, TRACOE® twist, or Rüsch® Traceofix® tracheostomy tubes equipped with nonfenestrated inner cannulas were tested in a tracheostomy-lung simulator. Transfenestration pressures and transfenestration leakage rates were measured during positive pressure ventilation. The impact of different ventilation modes, airway pressures, temperatures, and simulated static lung compliance settings on leakage characteristics was assessed. We observed substantial differences in transfenestration pressures and transfenestration leakage rates. The leakage rates of the best performing tubes were <3.5% of the delivered minute volume. At body temperature, the leakage rates of these tracheostomy tubes were <1%. The tracheal tube design was the main factor that determined the leakage characteristics. Careful tracheostomy tube selection permits the use of fenestrated tracheostomy tubes in patients receiving positive pressure ventilation immediately after stoma formation and minimises the risk of complications caused by transfenestration gas leakage, for example, subcutaneous emphysema. PMID:27073395

  15. Advanced pressure control modes of ventilation in cardiac surgery: Scanty evidence or unexplored terrain?

    PubMed Central

    Parida, Satyen; Bidkar, Prasanna Udupi

    2016-01-01

    Lung atelectasis resulting after cardiopulmonary bypass (CPB) can result in increased intrapulmonary shunting and consequent hypoxemia. Advanced pressure control modes of ventilation might have at least a theoretical advantage over conventional modes by assuring a minimum target tidal volume delivery at reasonable pressures, thus having potential advantages while ventilating patients with pulmonary atelectasis postcardiac surgery. However, the utility of these modes in the post-CPB setting have not been widely investigated, and their role in cardiac intensive care, therefore, remains quite limited. PMID:27076729

  16. Total Liquid Ventilation Provides Superior Respiratory Support to Conventional Mechanical Ventilation in a Large Animal Model of Severe Respiratory Failure

    PubMed Central

    Pohlmann, Joshua R; Brant, David O; Daul, Morgan A; Reoma, Junewai L; Kim, Anne C; Osterholzer, Kathryn R; Johnson, Kent J; Bartlett, Robert H; Cook, Keith E; Hirschl, Ronald B

    2011-01-01

    Total liquid ventilation (TLV) has the potential to provide respiratory support superior to conventional mechanical ventilation (CMV) in the acute respiratory distress syndrome (ARDS). However, laboratory studies are limited to trials in small animals for no longer than 4 hours. The objective of this study was to compare TLV and CMV in a large animal model of ARDS for 24 hours. Ten sheep weighing 53 ± 4 (SD) kg were anesthetized and ventilated with 100% oxygen. Oleic acid was injected into the pulmonary circulation until PaO2:FiO2 ≥ 60 mmHg, followed by transition to a protective CMV protocol (n=5) or TLV (n=5) for 24 hours. Pathophysiology was recorded and the lungs were harvested for histological analysis. Animals treated with CMV became progressively hypoxic and hypercarbic despite maximum ventilatory support. Sheep treated with TLV maintained normal blood gases with statistically greater PO2 (p<10−9) and lower PCO2 (p < 10−3) than the CMV group. Survival at 24 hours in the TLV and CMV groups were 100% and 40% respectively (p< 0.05). Thus, TLV provided gas exchange superior to CMV in this laboratory model of severe ARDS. PMID:21084968

  17. Ventilation during laparoscopic-assisted bariatric surgery: volume-controlled, pressure-controlled or volume-guaranteed pressure-regulated modes

    PubMed Central

    Dion, Joanna M; McKee, Chris; Tobias, Joseph D; Sohner, Paul; Herz, Daniel; Teich, Steven; Rice, Julie; Barry, N’ diris; Michalsky, Marc

    2014-01-01

    Introduction: Managing ventilation and oxygenation during laparoscopic procedures in severely obese patients undergoing weight loss surgery presents many challenges. Pressure-controlled ventilation, volume-guaranteed (PCV-VG) is a dual-control mode of ventilation and an alternative to pressure (PC) or volume (VC) controlled ventilation. PCV-VG features a user-selected tidal volume target, that is auto-regulated and pressure controlled. We hypothesized that PCV-VG ventilation would provide improved oxygenation and ventilation during laparoscopic bariatric surgery with a lower peak inflating pressure (PIP) than either PC or VC ventilation. Methods: This was a prospective cross-over cohort trial (n = 20). In random sequence each patient received the three modes of ventilation for 20 minutes during the laparoscopic portion of the procedure. For all modes of ventilation the goal tidal volume was 6-8 mL/kg, and the respiratory rate was adjusted to achieve normocarbia. The PIP, exhaled tidal volume, respiratory rate, and oxygen saturation were recorded every five minutes. At the end of 20 minutes, an arterial blood gas was obtained. Data were analyzed using a paired t-test. Results: PCV-VG and PC ventilation both resulted in significantly lower PIP (cmH2O) than VC ventilation (30.5 ± 3.0, 31.6 ± 4.9, and 36.3 ± 3.4 mmHg respectively; p < 0.01 for PCV-VG vs. VC and PC vs. VC). There was no difference in oxygenation (PaO2), ventilation (PaCO2) or hemodynamic variables between the three ventilation modes. Conclusions: In adolescents and young adults undergoing laparoscopic bariatric surgery, PCV-VG and PC were superior to VC ventilation in their ability to provide ventilation with the lowest PIP. PMID:25232415

  18. Treatment of idiopathic persistent hiccups with positive pressure ventilation -a case report-.

    PubMed

    Byun, Sung Hye; Jeon, Young Hoon

    2012-04-01

    A 41-year-old male patient presented with idiopathic persistent hiccups. The hiccups did not respond to pharmacologic treatments including cisapride, omeprazole, and baclofen. Phrenic nerve block was also ineffective. However, the persistent hiccups were successfully treated with short-term positive pressure ventilation using a short-acting muscle relaxant. PMID:22514778

  19. CO2 ventilation in the Critical Zone: synoptic- or turbulent-scale pressure pumping?

    NASA Astrophysics Data System (ADS)

    Sanchez-Cañete, E. P.; Serrano-Ortiz, P.; Kowalski, A. S.; Oyonarte, C.; Domingo, F.

    2011-12-01

    The critical zone can store large amounts of CO2, showing soil CO2 increases with depth fluctuating from 0.04 to 13.0% by volume. This CO2 can be emitted to the atmosphere through soil ventilation, causing the loss of CO2 stored in the subterranean spaces. The implications of ventilation processes for regional CO2 budgets are still poorly known. Here we analyze subterranean CO2 ventilation in two carbonate ecosystems situated in Southeast Spain, examining their main drivers and implications for the net ecosystem carbon balance measured with an Eddy Covariance system. The first ecosystem is a sub-humid, subalpine shrubland and has two sensors measuring CO2 molar fraction in the soil (25 cm depth) and in a borehole penetrating 7 m into a bedrock outcropping. The second ecosystem is a semiarid shrubland and has sensors buried at 0.15, 0.5 and 1.5 meters measuring a soil CO2 profile. At both sites the ecosystem CO2 fluxes are measured using an Eddy Covariance system. In the first ecosystem, the underground CO2 molar fraction decreases quickly with high friction velocity without periodicity, associated with turbulent pressure perturbations. However in the second ecosystem, the underground CO2 molar fraction increases and decreases with a regular periodicity induced by variations associated with synoptic pressure (passage of fronts). These results suggest pressure pumping mechanisms causing subsurface ventilation can occur over a range of scales, from turbulent (friction velocity) to synoptic.

  20. The effect of airway pressure and oscillation amplitude on ventilation in pre-term infants.

    PubMed

    Miedema, Martijn; de Jongh, Frans H; Frerichs, Inez; van Veenendaal, Mariette B; van Kaam, Anton H

    2012-08-01

    We determined the effect of lung recruitment and oscillation amplitude on regional oscillation volume and functional residual capacity (FRC) in high-frequency oscillatory ventilation (HFOV) used in pre-term infants with respiratory distress syndrome (RDS). Changes in lung volume, oscillation volume and carbon dioxide levels were recorded in 10 infants during a stepwise recruitment procedure, and an increase in pressure amplitude of 5 cmH(2)O was measured using electrical impedance tomography and transcutaneous monitoring. The pressures at maximal respiratory system compliance, maximal oscillation volume and minimal carbon dioxide levels were determined. Impedance data were analysed for the chest cross-section and predefined regions of interest. Despite the fixed pressure amplitude, the oscillation volume changed during the incremental pressure steps following a parabolic pattern, with an inverse relationship to the carbon dioxide pressures. The pressures corresponding with maximal compliance, maximal oscillation volume and minimal carbon dioxide were similar and highly correlated. Regional analysis showed similar findings. The increase in pressure amplitude resulted in increased oscillation volumes and decreased carbon dioxide levels, while FRC remained unchanged. In HFV pre-term infants with RDS, oscillation volumes are closely related to the position of ventilation in the pressure-volume envelope and the applied pressure amplitude. Changes in pressure amplitude do not seem to affect FRC. PMID:22362852

  1. High Frequency Nasal Ventilation for 21 Days Maintains Gas Exchange with Lower Respiratory Pressures and Promotes Alveolarization in Preterm Lambs

    PubMed Central

    Null, Donald M.; Alvord, Jeremy; Leavitt, Wendy; Wint, Albert; Dahl, Mar Janna; Presson, Angela P.; Lane, Robert H.; DiGeronimo, Robert J.; Yoder, Bradley A.; Albertine, Kurt H.

    2014-01-01

    Background Short-term high-frequency nasal ventilation (HFNV) of preterm neonates provides acceptable gas exchange compared to endotracheal intubation and intermittent mandatory ventilation (IMV). Whether long-term HFNV will provide acceptable gas exchange is unknown. We hypothesized that HFNV for up to 21d would lead to acceptable gas exchange at lower inspired oxygen (O2) levels and airway pressures compared to intubation and IMV. Methods Preterm lambs were exposed to antenatal steroids, and treated with perinatal surfactant and postnatal caffeine. Lambs were intubated and resuscitated by IMV. At ~3h of age, half of the lambs were switched to non-invasive HFNV. Support was for 3d or 21d. By design, PaO2 and PaCO2 were not different between groups. Results At 3d (n=5) and 21d (n=4) of HFNV, fractional inspired O2 (FiO2), peak inspiratory pressure, mean airway, intra-tracheal, and positive end-expiratory pressures, oxygenation index, and Alveolar-arterial gradient were significantly lower than matched periods of intubation and IMV. PaO2/FiO2 ratio was significantly higher at 3d and 21d of HFNV compared to matched intubation and IMV. HFNV led to better alveolarization at 3d and 21d. Conclusion Long-term HFNV provides acceptable gas exchange at lower inspired O2 levels and respiratory pressures compared to intubation and IMV. PMID:24378898

  2. Measurement of pressure-volume curves in patients on mechanical ventilation: methods and significance

    PubMed Central

    Lu, Qin; Rouby, Jean-Jacques

    2000-01-01

    Physiological background concerning mechanics of the respiratory system, techniques of measurement and clinical implications of pressure-volume curve measurement in mechanically ventilated patients are discussed in the present review. The significance of lower and upper inflection points, the assessment of positive end-expiratory pressure (PEEP)-induced alveolar recruitment and overdistension and rationale for optimizing ventilatory settings in patients with acute lung injury are presented. Evidence suggests that the continuous flow method is a simple and reliable technique for measuring pressure-volume curves at the bedside. In patients with acute respiratory failure, determination of lower and upper inflection points and measurement of respiratory compliance should become a part of the routine assessment of lung injury severity, allowing a bedside monitoring of the evolution of the lung disease and an optimization of mechanical ventilation. PMID:11094498

  3. Buoyancy and Pressure Induced Flow of Hot Gases in Vertical Shafts with Natural and Forced Ventilation

    NASA Astrophysics Data System (ADS)

    Jaluria, Yogesh; Tamm, Gunnar Olavi

    2014-11-01

    An experimental investigation was conducted to study buoyancy and pressure induced flow of hot gases in vertical shafts to model smoke propagation in elevator and ventilation shafts of high rise building fires. Various configurations were tested with regard to natural and forced ventilation imposed at the upper and lower surfaces of the vertical shaft. The aspect ratio was taken at a typical value of 6. From a lower vent, the inlet conditions for smoke and hot gases were varied in terms of the Reynolds and Grashof numbers. The forced ventilation at the upper or lower boundary was of the same order as the bulk shaft flow. Measurements were taken within the shaft to allow a detailed study of the steady state flow and thermal fields established for various shaft configurations and inlet conditions, from which optimal means for smoke alleviation in high rise building fires may be developed. Results indicated a wall plume as the primary transport mechanism for smoke propagating from the inlet towards the exhaust region. Recirculation and entrainment dominated at high inlet Grashof number flows, while increased inlet Reynolds numbers allowed greater mixing in the shaft. The development and stability of these flow patterns and their effects on the smoke behavior were assessed for several shaft configurations with different inlet conditions. The comparisons indicated that the fastest smoke removal and lowest overall shaft temperatures occur for a configuration with natural ventilation at the top surface and forced ventilation up from the shaft bottom.

  4. Measurement of airflow and pressure characteristics of a fan built in a car ventilation system

    NASA Astrophysics Data System (ADS)

    Pokorný, Jan; Poláček, Filip; Fojtlín, Miloš; Fišer, Jan; Jícha, Miroslav

    2016-03-01

    The aim of this study was to identify a set of operating points of a fan built in ventilation system of our test car. These operating points are given by the fan pressure characteristics and are defined by a pressure drop of the HVAC system (air ducts and vents) and volumetric flow rate of ventilation air. To cover a wide range of pressure drops situations, four cases of vent flaps setup were examined: (1) all vents opened, (2) only central vents closed (3) only central vents opened and (4) all vents closed. To cover a different volumetric flows, the each case was measured at least for four different speeds of fan defined by the fan voltage. It was observed that the pressure difference of the fan is proportional to the fan voltage and strongly depends on the throttling of the air distribution system by the settings of the vents flaps. In case of our test car we identified correlations between volumetric flow rate of ventilation air, fan pressure difference and fan voltage. These correlations will facilitate and reduce time costs of the following experiments with this test car.

  5. Optimizing lung aeration at birth using a sustained inflation and positive pressure ventilation in preterm rabbits

    PubMed Central

    te Pas, Arjan B.; Kitchen, Marcus J.; Lee, Katie; Wallace, Megan J.; Fouras, Andreas; Lewis, Robert A.; Yagi, Naoto; Uesugi, Kentaro; Hooper, Stuart B.

    2016-01-01

    Background: A sustained inflation (SI) facilitates lung aeration, but the most effective pressure and duration are unknown. We investigated the effect of gestational age (GA) and airway liquid volume on the required inflation pressure and SI duration. Methods: Rabbit kittens were delivered at 27, 29, and 30 d gestation, intubated and airway liquid was aspirated. Either no liquid (control) or 30 ml/kg of liquid was returned to the airways. Lung gas volumes were measured by plethysmography and phase-contrast X-ray-imaging. Starting at 22 cmH2O, airway pressure was increased until airflow commenced and pressure was then held constant. The SI was truncated when 20 ml/kg air had entered the lung and ventilation continued with intermittent positive pressure ventilation (iPPV). Results: Higher SI pressures and longer durations were required in 27-d kittens compared to 30-d kittens. During iPPV, 27-d kittens needed higher pressures and had lower functional residual capacity (FRC) compared to 30-d kittens. Adding lung liquid increased SI duration, reduced FRC, and increased resistance and pressures during iPPV in 29- and 30-d kittens. Conclusion: Immature kittens required higher starting pressures and longer SI durations to achieve a set inflation volume. Larger airway liquid volumes adversely affected lung function during iPPV in older but not young kittens. PMID:26991259

  6. Parametric instabilities of rotor-support systems with application to industrial ventilators

    NASA Technical Reports Server (NTRS)

    Parszewski, Z.; Krodkiemski, T.; Marynowski, K.

    1980-01-01

    Rotor support systems interaction with parametric excitation is considered for both unequal principal shaft stiffness (generators) and offset disc rotors (ventilators). Instability regions and types of instability are computed in the first case, and parametric resonances in the second case. Computed and experimental results are compared for laboratory machine models. A field case study of parametric vibrations in industrial ventilators is reported. Computed parametric resonances are confirmed in field measurements, and some industrial failures are explained. Also the dynamic influence and gyroscopic effect of supporting structures are shown and computed.

  7. Short-term exposure to high-pressure ventilation leads to pulmonary biotrauma and systemic inflammation in the rat.

    PubMed

    Hoegl, Sandra; Boost, Kim A; Flondor, Michael; Scheiermann, Patrick; Muhl, Heiko; Pfeilschifter, Josef; Zwissler, Bernhard; Hofstetter, Christian

    2008-04-01

    Though often lifesaving, mechanical ventilation itself bears the risk of lung damage [ventilator-induced lung injury (VILI)]. The underlying molecular mechanisms have not been fully elucidated, but stress-induced mediators seem to play an important role in biotrauma related to VILI. Our purpose was to evaluate an animal model of VILI that allows the observation of pathophysiologic changes along with parameters of biotrauma. For VILI induction, rats (n=16) were ventilated with a peak airway pressure (pmax) of 45 cm H2O and end-expiratory pressure (PEEP) of 0 for 20 min, followed by an observation time of 4 h. In the control group (n=8) the animals were ventilated with a pmax of 20 cm H2O and PEEP of 4. High-pressure ventilation resulted in an increase in paCO2 and a decrease in paO2 and mean arterial pressure. Only 4 animals out of 16 survived 4 h and VILI lungs showed severe macroscopic and microscopic damage, oedema and neutrophil influx. High-pressure ventilation increased the cytokine levels of macrophage inflammatory protein-2 and IL-1beta in bronchoalveolar lavage and plasma. VILI also induced pulmonary heat shock protein-70 expression and the activity of matrix metalloproteinases. The animal model used enabled us to observe the effect of high-pressure ventilation on mortality, lung damage/function and biotrauma. Thus, by combining barotrauma with biotrauma, this animal model may be suitable for studying therapeutical approaches to VILI. PMID:18360698

  8. Ventilation Transport Trade Study for Future Space Suit Life Support Systems

    NASA Technical Reports Server (NTRS)

    Kempf, Robert; Vogel, Matthew; Paul, Heather L.

    2008-01-01

    A new and advanced portable life support system (PLSS) for space suit surface exploration will require a durable, compact, and energy efficient system to transport the ventilation stream through the space suit. Current space suits used by NASA circulate the ventilation stream via a ball-bearing supported centrifugal fan. As NASA enters the design phase for the next generation PLSS, it is necessary to evaluate available technologies to determine what improvements can be made in mass, volume, power, and reliability for a ventilation transport system. Several air movement devices already designed for commercial, military, and space applications are optimized in these areas and could be adapted for EVA use. This paper summarizes the efforts to identify and compare the latest fan and bearing technologies to determine candidates for the next generation PLSS.

  9. Clinical Verification of A Clinical Decision Support System for Ventilator Weaning

    PubMed Central

    2013-01-01

    Background Weaning is typically regarded as a process of discontinuing mechanical ventilation in the daily practice of an intensive care unit (ICU). Among the ICU patients, 39%-40% need mechanical ventilator for sustaining their lives. The predictive rate of successful weaning achieved only 35-60% for decisions made by physicians. Clinical decision support systems (CDSSs) are promising in enhancing diagnostic performance and improve healthcare quality in clinical setting. To our knowledge, a prospective study has never been conducted to verify the effectiveness of the CDSS in ventilator weaning before. In this study, the CDSS capable of predicting weaning outcome and reducing duration of ventilator support for patients has been verified. Methods A total of 380 patients admitted to the respiratory care center of the hospital were randomly assigned to either control or study group. In the control group, patients were weaned with traditional weaning method, while in the study group, patients were weaned with CDSS monitored by physicians. After excluding the patients who transferred to other hospitals, refused further treatments, or expired the admission period, data of 168 and 144 patients in the study and control groups, respectively, were used for analysis. Results The results show that a sensitivity of 87.7% has been achieved, which is significantly higher (p<0.01) than the weaning determined by physicians (sensitivity: 61.4%). Furthermore, the days using mechanical ventilator for the study group (38.41 ± 3.35) is significantly (p<0.001) shorter than the control group (43.69 ± 14.89), with a decrease of 5.2 days in average, resulting in a saving of healthcare cost of NT$45,000 (US$1,500) per patient in the current Taiwanese National Health Insurance setting. Conclusions The CDSS is demonstrated to be effective in identifying the earliest time of ventilator weaning for patients to resume and sustain spontaneous breathing, thereby avoiding unnecessary prolonged

  10. Bronchoscopic intubation during continuous nasal positive pressure ventilation in the treatment of hypoxemic respiratory failure.

    PubMed

    Barjaktarevic, Igor; Berlin, David

    2015-03-01

    Endotracheal intubation is difficult in patients with hypoxemic respiratory failure who deteriorate despite treatment with noninvasive positive pressure ventilation (NIPPV). Maintaining NIPPV during intubation may prevent alveolar derecruitment and deterioration in gas exchange. We report a case series of 10 nonconsecutive patients with NIPPV failure who were intubated via a flexible bronchoscope during nasal mask positive pressure ventilation. All 10 patients were intubated in the first attempt. Hypotension was the most frequent complication (33%). Mean decrease in oxyhemoglobin saturation during the procedure was 4.7 ± 3.1. This method of intubation may extend the benefits of preoxygenation throughout the whole process of endotracheal intubation. It requires an experienced operator and partially cooperative patients. A prospective trial is necessary to determine the best intubation method for NIPPV failure. PMID:24243561

  11. A comparison of synchronized intermittent mandatory ventilation and pressure-regulated volume control ventilation in elderly patients with acute exacerbations of COPD and respiratory failure

    PubMed Central

    Chang, Suchi; Shi, Jindong; Fu, Cuiping; Wu, Xu; Li, Shanqun

    2016-01-01

    Background COPD is the third leading cause of death worldwide. Acute exacerbations of COPD may cause respiratory failure, requiring intensive care unit admission and mechanical ventilation. Intensive care unit patients with acute exacerbations of COPD requiring mechanical ventilation have higher mortality rates than other hospitalized patients. Although mechanical ventilation is the most effective intervention for these conditions, invasive ventilation techniques have yielded variable effects. Objective We evaluated pressure-regulated volume control (PRVC) ventilation treatment efficacy and preventive effects on pulmonary barotrauma in elderly COPD patients with respiratory failure. Patients and methods Thirty-nine intubated patients were divided into experimental and control groups and treated with the PRVC and synchronized intermittent mandatory ventilation – volume control methods, respectively. Vital signs, respiratory mechanics, and arterial blood gas analyses were monitored for 2–4 hours and 48 hours. Results Both groups showed rapidly improved pH, partial pressure of oxygen (PaO2), and PaO2 per fraction of inspired O2 levels and lower partial pressure of carbon dioxide (PaCO2) levels. The pH and PaCO2 levels at 2–4 hours were lower and higher, respectively, in the test group than those in the control group (P<0.05 for both); after 48 hours, blood gas analyses showed no statistical difference in any marker (P>0.05). Vital signs during 2–4 hours and 48 hours of treatment showed no statistical difference in either group (P>0.05). The level of peak inspiratory pressure in the experimental group after mechanical ventilation for 2–4 hours and 48 hours was significantly lower than that in the control group (P<0.05), while other variables were not significantly different between groups (P>0.05). Conclusion Among elderly COPD patients with respiratory failure, application of PRVC resulted in rapid improvement in arterial blood gas analyses while maintaining

  12. Histopathologic pulmonary changes from mechanical ventilation at high peak airway pressures.

    PubMed

    Tsuno, K; Miura, K; Takeya, M; Kolobow, T; Morioka, T

    1991-05-01

    We investigated the histopathologic pulmonary changes induced by mechanical pulmonary ventilation (MV) with a high peak airway pressure and a large tidal volume in healthy baby pigs. Eleven animals were mechanically ventilated at a peak inspiratory pressure (PIP) of 40 cm H2O, a respiratory rate (RR) of 20 min-1, a positive end-expiratory pressure (PEEP) of 3 to 5 cm H2O, and an FIO2 of 0.4. High airway pressure MV was terminated in 22 +/- 11 h because of severe hypoxemia in the animals. Five of the baby pigs were killed for gross and light microscope studies. The pulmonary changes consisted of alveolar hemorrhage, alveolar neutrophil infiltration, alveolar macrophage and type II pneumocyte proliferation, interstitial congestion and thickening, interstitial lymphocyte infiltration, emphysematous change, and hyaline membrane formation. Those lesions were similar to that seen in the early stage of the adult respiratory distress syndrome (ARDS). The remaining six animals were treated for 3 to 6 days with conventional respiratory care with appropriate ventilator settings. Prominent organized alveolar exudate in addition to lesions was also found in the five animals. These findings were indistinguishable from the clinical late stage of ARDS. Six control animals were mechanically ventilated at a PIP of less than 18 cm H2O, a RR of 20 min-1, a PEEP of 3 to 5 cm H2O, and an FIO2 of 0.4 for 48 h. They showed no notable changes in lung functions and histopathologic findings. Aggressive MV with a high PIP is often applied to patients with respiratory distress to attain adequate pulmonary gas exchange.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2024823

  13. Low-intensity noninvasive ventilation: Lower pressure, more exacerbations of chronic respiratory failure

    PubMed Central

    Kadowaki, Toru; Wakabayashi, Kiryo; Kimura, Masahiro; Kobayashi, Kanako; Ikeda, Toshikazu; Yano, Shuichi

    2016-01-01

    BACKGROUND: For patients with chronic respiratory failure (CRF) who are treated with noninvasive positive pressure ventilation (NPPV), a little is known regarding the effects of low-intensity NPPV (LI-NPPV) on the clinical course of CRF and the frequency of adjustments in these patients. OBJECTIVES: This study investigated the effects of LI-NPPV on the clinical course of patients with CRF as compared with patients who were treated with conventional NPPV (C-NPPV) and determined how frequently NPPV was adjusted during therapy. METHODS: Clinical data from 21 patients who received long-term NPPV were retrospectively analyzed. Patients were categorized into two groups based on the level of initial pressure support (PS): C-NPPV group (PS ≥ 10 cm H2O) and LI-NPPV group (PS < 10 cm H2O). RESULTS: Patients in the LI-NPPV group had significantly more exacerbations of CRF (P < 0.05). There was no significant difference in the number of patients who required adjustments of NPPV settings between the two groups. There was no significant difference in PaCO2 levels 1 month after the start of NPPV between the two groups; however, PaCO2 levels were significantly lower after 1 year in the C-group (P < 0.001). Seventy-one percent of LI-NPPV patients and 43% of C-NPPV patients needed NPPV adjustments. CONCLUSIONS: Attention should be paid to CRF patients who are initially administered LI-NPPV; they should be carefully observed because they can develop more exacerbations of CRF than patients undergoing C-NPPV. If possible, higher initial PS should be administered to prevent CRF exacerbations. PMID:27168863

  14. The basis and basics of mechanical ventilation.

    PubMed

    Bone, R C; Eubanks, D H

    1991-06-01

    The development of mechanical ventilators and the procedures for their application began with the simple foot pump developed by Fell O'Dwyer in 1888. Ventilators have progressed through three generations, beginning with intermittent positive pressure breathing units such as the Bird and Bennett device in the 1960s. These were followed by second-generation units--represented by the Bennett MA-2 ventilator--in the 1970s, and the third-generation microprocessor-controlled units of today. During this evolutionary process clinicians recognized Types I and II respiratory failure as being indicators for mechanical ventilatory support. More recently investigators have expanded, clarified, and clinically applied the physiology of the work of breathing (described by Julius Comroe and other pioneers) to muscle fatigue, requiring ventilatory support. A ventilator classification system can help the clinician understand how ventilators function and under what conditions they may fail to operate as desired. Pressure-support ventilation is an example of how industry has responded to a clinical need--that is, to unload the work of breathing. All positive pressure ventilators generate tidal volumes by using power sources such as medical gas cylinders, air compressors, electrically driven turbines, or piston driven motors. Positive end-expiratory pressures, synchronized intermittent mandatory ventilation, pressure support ventilation, pressure release ventilation, and mandatory minute ventilation, are examples of the special functions available on modern ventilators. Modern third-generation ventilators use microprocessors to control operational functions and monitors. Because these units have incorporated the experience learned from earlier ventilators, it is imperative that clinicians understand basic ventilator operation and application in order to most effectively prescribe and assess their use. PMID:2036934

  15. Influence of Barometric Pressure Changes on Ventilation Conditions in Deep Mines

    NASA Astrophysics Data System (ADS)

    Wasilewski, Stanisław

    2014-10-01

    Barometric air pressure and its changes have a critical impact on ventilation conditions in the underground workings of deep mines. Changes in pressure are particularly important because they are responsible for the transient states of ventilation conditions, therefore, assessing the scale of pressure change is essential. Unfortunately, previously for many years in the Polish mining industry barometric pressure was recorded only on tapes of mechanical barographs by the ventilation department on the surface and therefore such dependencies of methane concentration due to barometric pressure changes have not been properly documented. Today, after the implementation in mines of instruments enabling the monitoring of absolute pressure in the workings of mines (Wasilewski, 2009) the conditions have been created to study the influence of pressure changes on changes of air parameters in the mine workings. Barometric pressure changes were observed and recorded over a course of approximately two years using monitoring system that utilized high accuracy pressure sensors on the surface and in selected workings of an underground mine. This paper presents a statistical analysis of the data that we generated from assessing pressure changes on the surface and at selected underground points in the mine. In the article, which presents the results of the first part of the study, some examples of when significant changes in pressure prior to the tragic events, which were not accompanied by changes in the methane concentration in mine workings, will also be shown. Interestingly, we found that the relationship between methane ignitions and explosions in longwall gob mined via the cave-in method is associated with changes in the barometric pressure. Several instances of methane ignitions and explosions in the gob of cave-in longwalls in recent years were compared with background barometric pressure changes. Research carried out in within the strategic project "Improving work safety in

  16. Facial pressure zones of an oronasal interface for noninvasive ventilation: a computer model analysis* **

    PubMed Central

    Barros, Luana Souto; Talaia, Pedro; Drummond, Marta; Natal-Jorge, Renato

    2014-01-01

    OBJECTIVE: To study the effects of an oronasal interface (OI) for noninvasive ventilation, using a three-dimensional (3D) computational model with the ability to simulate and evaluate the main pressure zones (PZs) of the OI on the human face. METHODS: We used a 3D digital model of the human face, based on a pre-established geometric model. The model simulated soft tissues, skull, and nasal cartilage. The geometric model was obtained by 3D laser scanning and post-processed for use in the model created, with the objective of separating the cushion from the frame. A computer simulation was performed to determine the pressure required in order to create the facial PZs. We obtained descriptive graphical images of the PZs and their intensity. RESULTS: For the graphical analyses of each face-OI model pair and their respective evaluations, we ran 21 simulations. The computer model identified several high-impact PZs in the nasal bridge and paranasal regions. The variation in soft tissue depth had a direct impact on the amount of pressure applied (438-724 cmH2O). CONCLUSIONS: The computer simulation results indicate that, in patients submitted to noninvasive ventilation with an OI, the probability of skin lesion is higher in the nasal bridge and paranasal regions. This methodology could increase the applicability of biomechanical research on noninvasive ventilation interfaces, providing the information needed in order to choose the interface that best minimizes the risk of skin lesion. PMID:25610506

  17. Severe subcutaneous emphysema and pneumomediastinum secondary to noninvasive ventilation support in status asthmaticus

    PubMed Central

    González García, Lara; Rey, Corsino; Medina, Alberto; Mayordomo-Colunga, Juan

    2016-01-01

    A 12-year-old male with status asthmaticus developed subcutaneous emphysema and pneumomediastinum. He was transferred to our unit, where he received noninvasive ventilation (NIV). This respiratory support technique is not an absolute contraindication in these cases. After 2 h on NIV, he worsened sharply and the subcutaneous emphysema got bigger suddenly. He needed invasive ventilation for 5 days. Final outcome was satisfactory. This case illustrates that it is mandatory to keep a high level of vigilance when using NIV in patients with air leaks.

  18. Severe subcutaneous emphysema and pneumomediastinum secondary to noninvasive ventilation support in status asthmaticus.

    PubMed

    González García, Lara; Rey, Corsino; Medina, Alberto; Mayordomo-Colunga, Juan

    2016-04-01

    A 12-year-old male with status asthmaticus developed subcutaneous emphysema and pneumomediastinum. He was transferred to our unit, where he received noninvasive ventilation (NIV). This respiratory support technique is not an absolute contraindication in these cases. After 2 h on NIV, he worsened sharply and the subcutaneous emphysema got bigger suddenly. He needed invasive ventilation for 5 days. Final outcome was satisfactory. This case illustrates that it is mandatory to keep a high level of vigilance when using NIV in patients with air leaks. PMID:27303140

  19. Partial Support Ventilation and Mitochondrial-Targeted Antioxidants Protect against Ventilator-Induced Decreases in Diaphragm Muscle Protein Synthesis

    PubMed Central

    Hudson, Matthew B.; Smuder, Ashley J.; Nelson, W. Bradley; Wiggs, Michael P.; Shimkus, Kevin L.; Fluckey, James D.; Szeto, Hazel H.; Powers, Scott K.

    2015-01-01

    Mechanical ventilation (MV) is a life-saving intervention in patients in respiratory failure. Unfortunately, prolonged MV results in the rapid development of diaphragm atrophy and weakness. MV-induced diaphragmatic weakness is significant because inspiratory muscle dysfunction is a risk factor for problematic weaning from MV. Therefore, developing a clinical intervention to prevent MV-induced diaphragm atrophy is important. In this regard, MV-induced diaphragmatic atrophy occurs due to both increased proteolysis and decreased protein synthesis. While efforts to impede MV-induced increased proteolysis in the diaphragm are well-documented, only one study has investigated methods of preserving diaphragmatic protein synthesis during prolonged MV. Therefore, we evaluated the efficacy of two therapeutic interventions that, conceptually, have the potential to sustain protein synthesis in the rat diaphragm during prolonged MV. Specifically, these experiments were designed to: 1) determine if partial-support MV will protect against the decrease in diaphragmatic protein synthesis that occurs during prolonged full-support MV; and 2) establish if treatment with a mitochondrial-targeted antioxidant will maintain diaphragm protein synthesis during full-support MV. Compared to spontaneously breathing animals, full support MV resulted in a significant decline in diaphragmatic protein synthesis during 12 hours of MV. In contrast, diaphragm protein synthesis rates were maintained during partial support MV at levels comparable to spontaneous breathing animals. Further, treatment of animals with a mitochondrial-targeted antioxidant prevented oxidative stress during full support MV and maintained diaphragm protein synthesis at the level of spontaneous breathing animals. We conclude that treatment with mitochondrial-targeted antioxidants or the use of partial-support MV are potential strategies to preserve diaphragm protein synthesis during prolonged MV. PMID:26361212

  20. [Numerical simulation of the internal noise in the pressure generator of a continuous positive airway pressure ventilator].

    PubMed

    Cheng, Yunzhang; Huang, Fangfang; Zhu, Lihua

    2013-04-01

    It is important to overcome the problem of noise for the research and development of ventilator technologies. Previous research of this subject showed that the pressure generator, produced by German EMB-PAPST Company and specially used for continuous positive airway pressure (CPAP) ventilator, created noise easily, due to local backflow in the volute, uneven velocity distribution in the impeller and local negative pressure in the inlet of the impeller. Based on the previous research, a combination of the computational fluid dynamics (CFD) software FLUENT and steady-state solution of noise source of Reynolds-Averaged Navier-Stokes (RANS) was used in this study. We combined equation of Lilley and Synthetic Turbulence to get the information about speed fluctuation of the pressure generator, which is used to finish noise prediction. After detailed analysis, it showed that noise source of different degrees spreaded around the inlet of the impeller and the volute, interface of blade edge and corner of the volute tongue, which influenced its overall performance to certain extent. Therefore, its structural design needs to be improved. PMID:23858754

  1. Fatal brain gas embolism during non-invasive positive pressure ventilation

    PubMed Central

    Rivara, Claire B; Chevrolet, Jean-Claude; Gasche, Yvan; Charbonney, Emmanuel

    2008-01-01

    Gas embolism is a dreaded complication following invasive medical procedures, traumatic lung injury and decompression accidents. We report a case of fatal gas embolism following the use of non-invasive ventilation (NIV) with bilevel positive airway pressure (BiPAP). The patient initially underwent left bronchial artery embolisation for massive haemoptysis in the context of severe tuberculotic sequels. Under NIV and after heavy coughing he became hemiparetic and his level of consciousness suddenly dropped. Computed tomography of the brain showed multiple air embolism and ischaemic lesions were confirmed by magnetic resonance imaging. Echocardiographic investigations showed no intracardiac defect. Vasculo-pulmonary abnormalities in the context of heavy coughing and non-invasive ventilation may have played a major role in the occurrence of this event. New neurological events in a patient with tuberculotic sequels or any known vascular pulmonary abnormalities and NIV should raise the suspicion of brain gas embolism. PMID:21716825

  2. Noninvasive positive pressure ventilation as treatment for acute respiratory failure in critically ill patients

    PubMed Central

    Antonelli, Massimo; Conti, Giorgio

    2000-01-01

    Our current state of knowledge on noninvasive positive pressure ventilation (NPPV) and technical aspects are discussed in the present review. In patients with chronic obstructive pulmonary disease, NPPV can be considered a valid therapeutic option to prevent endotracheal intubation. Evidence suggests that, before eventual endotracheal intubation, NPPV should be considered as first-line intervention in the early phases of acute exacerbation of chronic obstructive pulmonary disease. Small randomized and non-randomized studies on the application of NPPV in patients with acute hypoxaemic respiratory failure showed promising results, with reduction in complications such as sinusitis and ventilator-associated pneumonia, and in the duration of intensive care unit stay. The conventional use of NPPV in hypoxaemic acute respiratory failure still remains controversial, however. Large randomized studies are still needed before extensive clinical application in this condition. PMID:11094492

  3. [Implementation of modern trends in the methods of the ventilation support in the new apparatus for artificial lung ventilation Avenir-221 P].

    PubMed

    Gal'perin, Iu Sh; Alkhimova, L R; Dmitriev, N D; Kozlova, I A; Nemirovskiĭ, S B; Makarov, M V; Safronov, A Iu

    2005-01-01

    In the new ventilator Avenir-221 P modern lines of development of ventilation support in intensive therapy of adults and children are implemented. The capacities of the ventilator are successfully combined with its technical decisions which include microprocessor parametrical controlling, programming-controlled electric drive, an information saturation, intuitively clear control system, protection against interruption of power supply sources and oxygen feeding falls. A set of functional characteristics (modes VCV, PCV, Ass/Contr, PSV, SIMV, PEEP, Sigh, etc.) in combination with an original design make the device the most accessible and promising for application in intensive care and resuscitation units of a wide network of Russian hospitals and clinics. The ventilator Avenir-221 P has passed all required tests and is presently commercially available. PMID:16491658

  4. Use of the Draeger Apollo to Deliver Bilevel Positive Pressure Ventilation During Awake Frontal Craniotomy for a Patient with Severe Chronic Obstructive Pulmonary Disease.

    PubMed

    Lee, Susie So-Hyun; Berman, Mitchell F

    2015-12-01

    In this case report, we describe the use of the Draeger Apollo anesthesia machine to deliver bilevel positive airway pressure (BiPAP) to a patient with severe chronic obstructive pulmonary disease and a history of lung resection undergoing frontal craniotomy for the removal of a brain tumor under moderate to deep sedation. BiPAP in the perioperative period has been described for purposes of preoxygenation and postextubation recruitment. Although its utility as a mode of ventilation during moderate to deep sedation has been demonstrated, it has not come into widespread use. We describe the intraoperative use of pressure support mode on the anesthesia machine to deliver noninvasive positive pressure ventilation through a standard anesthesia mask. Given its ease of access and effectiveness, it is our belief that intraoperative BiPAP may reduce hypoxemia and/or hypercarbia in patients with chronic obstructive pulmonary disease and obstructive sleep apnea undergoing moderate to deep sedation. PMID:26588034

  5. The influence of controlled mandatory ventilation (CMV), intermittent mandatory ventilation (IMV) and biphasic intermittent positive airway pressure (BIPAP) on duration of intubation and consumption of analgesics and sedatives. A prospective analysis in 596 patients following adult cardiac surgery.

    PubMed

    Rathgeber, J; Schorn, B; Falk, V; Kazmaier, S; Spiegel, T; Burchardi, H

    1997-11-01

    The aim of the study was the determination of the influence of ventilation modes on the consumption of analgesics and sedatives, duration of intubation and pulmonary gas exchange. Assist/controlled mandatory ventilation (S-CMV, 123 patients), synchronized intermittent mandatory ventilation (S-IMV, 431 patients) and biphasic positive airway pressure ventilation (BIPAP, 42 patients) were compared in a prospective, controlled, open clinical trial over an 18-month period. Five hundred and ninety-six adult patients with normal pulmonary function before surgery and uneventful course following coronary artery bypass graft surgery were studied. Patients ventilated with BIPAP had a significantly shorter mean duration of intubation (10.1 h, P < 0.05) than patients treated with S-IMV (14.7 h) and S-CMV (13.2 h). In the S-CMV group, 39.9% of the patients required single or multiple doses of midazolam, but only 13.5% in the S-IMV group and 9.5% in the BIPAP group. The mean total amount of midazolam administered to these patients was significantly higher in the S-CMV group (8.8 mg) than in the S-IMV group (6.6 mg, P < 0.05) and in the BIPAP group (4.3 mg, P < 0.05). The consumption of pethidine and piritramide did not differ between S-CMV and S-IMV, but was significantly lower during BIPAP (P < 0.05). After extubation the patients' PaCO2 was highest in the S-CMV group. We conclude that ventilatory support with BIPAP reduces the consumption of analgesics and sedatives, and the duration of intubation. The possibility of unrestricted spontaneous breathing in all phases of the respiratory cycle is considered to be the reason. BIPAP seems to be an alternative to S-CMV and S-IMV in short-term ventilated patient. PMID:9466092

  6. Low-frequency positive pressure ventilation with extracorporeal carbon dioxide removal (LFPPV-ECCO2R): an experimental study.

    PubMed

    Gattinoni, L; Kolobow, T; Tomlinson, T; Iapichino, G; Samaja, M; White, D; Pierce, J

    1978-01-01

    We describe a new form of mechanical pulmonary ventilation, low-frequency positive pressure ventilation with extracorporeal CO2 removal (LEPPV-ECCO2R). In a series of animal studies the rate of mechanical ventilation was 0.66, 1, 2, and 4 min-1 at a tidal volume of 3, 10, and 15 ml kg-1. We were able to maintain normal blood gases and normal lung volumes and lung mechanics even at the lowest ventilator rate with tidal volumes of 10 or 15 ml kg-1. Each experiment lasted 7 hours. Our data suggest a possible new dimension in the management of a difficult patient on mechanical pulmonary ventilation. PMID:30341

  7. Hepatic effects of lung-protective pressure-controlled ventilation and a combination of high-frequency oscillatory ventilation and extracorporeal lung assist in experimental lung injury

    PubMed Central

    Kredel, Markus; Muellenbach, Ralf M.; Johannes, Amélie; Brederlau, Joerg; Roewer, Norbert; Wunder, Christian

    2011-01-01

    Summary Background Ventilation with high positive end-expiratory pressure (PEEP) can lead to hepatic dysfunction. The aim of this study was to investigate the hepatic effects of strategies using high airway pressures either in pressure-controlled ventilation (PCV) or in high-frequency oscillatory ventilation (HFOV) combined with an arteriovenous extracorporeal lung assist (ECLA). Material/Methods Pietrain pigs underwent induction of lung injury by saline lavage. Ventilation was continued for 24 hours either as PCV with tidal volumes of 6 ml/kg and PEEP 3 cmH2O above the lower inflection point of the pressure-volume curve or as HFOV (≥12 Hz) with a mean tracheal airway pressure 3 cmH2O above the lower inflection point combined with arteriovenous ECLA (HFOV+ECLA). Fluids and norepinephrine stabilized the circulation. The indocyanine green plasma disappearance rate, serum bilirubin, aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, alkaline phosphatase, glutamate dehydrogenase, lactate dehydrogenase and creatine kinase were determined repeatedly. Finally, liver neutrophils were counted and liver cell apoptosis was assessed by terminal deoxynucleotidyl transferase nick end labeling (TUNEL). Results Aspartate aminotransferase increased in the PCV group about three-fold and in the HFOV+ECLA group five-fold (p<0.001). Correspondingly, creatine kinase increased about two-fold and four-fold, respectively (p<0.001). Lactate dehydrogenase was increased in the HFOV+ECLA group (p<0.028). The number of neutrophils infiltrating the liver tissue and the apoptotic index were low. Conclusions High airway pressure PCV and HFOV with ECLA in the treatment of lavage-induced lung injury in pigs did not cause liver dysfunction or damage. The detected elevation of enzymes might be of extrahepatic origin. PMID:21959601

  8. Development of a time-cycled volume-controlled pressure-limited respirator and lung mechanics system for total liquid ventilation.

    PubMed

    Larrabe, J L; Alvarez, F J; Cuesta, E G; Valls-i-Soler, A; Alfonso, L F; Arnaiz, A; Fernández, M B; Loureiro, B; Publicover, N G; Roman, L; Casla, J A; Gómez, M A

    2001-10-01

    Total liquid ventilation can support gas exchange in animal models of lung injury. Clinical application awaits further technical improvements and performance verification. Our aim was to develop a liquid ventilator, able to deliver accurate tidal volumes, and a computerized system for measuring lung mechanics. The computer-assisted, piston-driven respirator controlled ventilatory parameters that were displayed and modified on a real-time basis. Pressure and temperature transducers along with a lineal displacement controller provided the necessary signals to calculate lung mechanics. Ten newborn lambs (<6 days old) with respiratory failure induced by lung lavage, were monitored using the system. Electromechanical, hydraulic, and data acquisition/analysis components of the ventilator were developed and tested in animals with respiratory failure. All pulmonary signals were collected synchronized in time, displayed in real-time, and archived on digital media. The total mean error (due to transducers, analog-to-digital conversion, amplifiers, etc.) was less than 5% compared with calibrated signals. Components (tubing, pistons, etc.) in contact with exchange fluids were developed so that they could be readily switched, a feature that will be important in clinical settings. Improvements in gas exchange and lung mechanics were observed during liquid ventilation, without impairment of cardiovascular profiles. The total liquid ventilator maintained accurate control of tidal volumes and the sequencing of inspiration/expiration. The computerized system demonstrated its ability to monitor in vivo lung mechanics, providing valuable data for early decision making. PMID:11585037

  9. Maximum inspiratory pressure and rapid shallow breathing index as predictors of successful ventilator weaning

    PubMed Central

    Bien, Umilson dos Santos; Souza, Gerson Fonseca; Campos, Elisangela Siqueira; Farah de Carvalho, Etiene; Fernandes, Matheus Guedes; Santoro, Ilka; Costa, Dirceu; Arena, Ross; Sampaio, Luciana Maria Malosá

    2015-01-01

    [Purpose] To investigate the predictive value of maximum inspiratory pressure (MIP) and the rapid shallow breathing index (RSBI) in a ventilator weaning protocol and to evaluate the differences between clinical and surgical patients in the intensive care unit. [Subjects and Methods] Patients aged ≥15 years who underwent orotracheal intubation for mechanical ventilation and who met the criteria of the weaning protocol were included in the study. Receiver operating characteristic (ROC) curves were calculated for the analysis of each index. [Results] Logistic regression analysis was also performed. MIP showed greater sensitivity and specificity [area under the curve (AUC): 0.95 vs. 0.89] and likelihood ratios (LR) (positive(+): 20.85 vs. 9.45; negative(−): 0.07 vs. 0.17) than RSBI in the overall sample (OS) as well as in clinical patients (CP) (AUC: 0.99 vs. 0.90; LR+: 24.66 vs. 7.22; LR-: 0.01 vs. 0.15) and surgical patients (SP) (AUC: 0.99 vs. 0.87; LR+: 9.33 vs. 5.86; LR−: 0.07 vs. 0.14). The logistic regression analysis revealed that both parameters were significantly associated with the weaning success. The MIP showed greater accuracy than the RSBI (OS: 0.93 vs. 0.85; CP: 0.98 vs. 0.87; SP: 0.93 vs. 0.87). [Conclusion] Both parameters are good predictors of successful ventilator weaning. PMID:26834339

  10. Maximum inspiratory pressure and rapid shallow breathing index as predictors of successful ventilator weaning.

    PubMed

    Bien, Umilson Dos Santos; Souza, Gerson Fonseca; Campos, Elisangela Siqueira; Farah de Carvalho, Etiene; Fernandes, Matheus Guedes; Santoro, Ilka; Costa, Dirceu; Arena, Ross; Sampaio, Luciana Maria Malosá

    2015-12-01

    [Purpose] To investigate the predictive value of maximum inspiratory pressure (MIP) and the rapid shallow breathing index (RSBI) in a ventilator weaning protocol and to evaluate the differences between clinical and surgical patients in the intensive care unit. [Subjects and Methods] Patients aged ≥15 years who underwent orotracheal intubation for mechanical ventilation and who met the criteria of the weaning protocol were included in the study. Receiver operating characteristic (ROC) curves were calculated for the analysis of each index. [Results] Logistic regression analysis was also performed. MIP showed greater sensitivity and specificity [area under the curve (AUC): 0.95 vs. 0.89] and likelihood ratios (LR) (positive(+): 20.85 vs. 9.45; negative(-): 0.07 vs. 0.17) than RSBI in the overall sample (OS) as well as in clinical patients (CP) (AUC: 0.99 vs. 0.90; LR+: 24.66 vs. 7.22; LR-: 0.01 vs. 0.15) and surgical patients (SP) (AUC: 0.99 vs. 0.87; LR+: 9.33 vs. 5.86; LR-: 0.07 vs. 0.14). The logistic regression analysis revealed that both parameters were significantly associated with the weaning success. The MIP showed greater accuracy than the RSBI (OS: 0.93 vs. 0.85; CP: 0.98 vs. 0.87; SP: 0.93 vs. 0.87). [Conclusion] Both parameters are good predictors of successful ventilator weaning. PMID:26834339

  11. Using Thoracic Ultrasonography to Accurately Assess Pneumothorax Progression During Positive Pressure Ventilation

    PubMed Central

    Lossius, Hans Morten; Wemmelund, Kristian; Stokkeland, Paal Johan; Knudsen, Lars; Sloth, Erik

    2013-01-01

    Background: Although thoracic ultrasonography accurately determines the size and extent of occult pneumothoraces (PTXs) in spontaneously breathing patients, there is uncertainty about patients receiving positive pressure ventilation. We compared the lung point (ie, the area where the collapsed lung still adheres to the inside of the chest wall) using the two modalities ultrasonography and CT scanning to determine whether ultrasonography can be used reliably to assess PTX progression in a positive-pressure-ventilated porcine model. Methods: Air was introduced in incremental steps into five hemithoraces in three intubated porcine models. The lung point was identified on ultrasound imaging and referenced against the lateral limit of the intrapleural air space identified on the CT scans. The distance from the sternum to the lung point (S-LP) was measured on the CT scans and correlated to the insufflated air volume. Results: The mean total difference between the 131 ultrasound and CT scan lung points was 6.8 mm (SD, 7.1 mm; range, 0.0-29.3 mm). A mixed-model regression analysis showed a linear relationship between the S-LP distances and the PTX volume (P < .001). Conclusions: In an experimental porcine model, we found a linear relation between the PTX size and the lateral position of the lung point. The accuracy of thoracic ultrasonography for identifying the lung point (and, thus, the PTX extent) was comparable to that of CT imaging. These clinically relevant results suggest that ultrasonography may be safe and accurate in monitoring PTX progression during positive pressure ventilation. PMID:23188058

  12. Positive End-Expiratory Pressure and Variable Ventilation in Lung-Healthy Rats under General Anesthesia

    PubMed Central

    Camilo, Luciana M.; Ávila, Mariana B.; Cruz, Luis Felipe S.; Ribeiro, Gabriel C. M.; Spieth, Peter M.; Reske, Andreas A.; Amato, Marcelo; Giannella-Neto, Antonio; Zin, Walter A.; Carvalho, Alysson R.

    2014-01-01

    Objectives Variable ventilation (VV) seems to improve respiratory function in acute lung injury and may be combined with positive end-expiratory pressure (PEEP) in order to protect the lungs even in healthy subjects. We hypothesized that VV in combination with moderate levels of PEEP reduce the deterioration of pulmonary function related to general anesthesia. Hence, we aimed at evaluating the alveolar stability and lung protection of the combination of VV at different PEEP levels. Design Randomized experimental study. Setting Animal research facility. Subjects Forty-nine male Wistar rats (200–270 g). Interventions Animals were ventilated during 2 hours with protective low tidal volume (VT) in volume control ventilation (VCV) or VV and PEEP adjusted at the level of minimum respiratory system elastance (Ers), obtained during a decremental PEEP trial subsequent to a recruitment maneuver, and 2 cmH2O above or below of this level. Measurements and Main Results Ers, gas exchange and hemodynamic variables were measured. Cytokines were determined in lung homogenate and plasma samples and left lung was used for histologic analysis and diffuse alveolar damage scoring. A progressive time-dependent increase in Ers was observed independent on ventilatory mode or PEEP level. Despite of that, the rate of increase of Ers and lung tissue IL-1 beta concentration were significantly lower in VV than in VCV at the level of the PEEP of minimum Ers. A significant increase in lung tissue cytokines (IL-6, IL-1 beta, CINC-1 and TNF-alpha) as well as a ventral to dorsal and cranial to caudal reduction in aeration was observed in all ventilated rats with no significant differences among groups. Conclusions VV combined with PEEP adjusted at the level of the PEEP of minimal Ers seemed to better prevent anesthesia-induced atelectasis and might improve lung protection throughout general anesthesia. PMID:25383882

  13. Use of volume-targeted non-invasive bilevel positive airway pressure ventilation in a patient with amyotrophic lateral sclerosis*,**

    PubMed Central

    Diaz-Abad, Montserrat; Brown, John Edward

    2014-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease in which most patients die of respiratory failure. Although volume-targeted non-invasive bilevel positive airway pressure (BPAP) ventilation has been studied in patients with chronic respiratory failure of various etiologies, its use in ALS has not been reported. We present the case of a 66-year-old woman with ALS and respiratory failure treated with volume-targeted BPAP ventilation for 15 weeks. Weekly data downloads showed that disease progression was associated with increased respiratory muscle weakness, decreased spontaneous breathing, and increased use of non-invasive positive pressure ventilation, whereas tidal volume and minute ventilation remained relatively constant. PMID:25210968

  14. Stable Small Animal Mechanical Ventilation for Dynamic Lung Imaging to Support Computational Fluid Dynamics Models

    SciTech Connect

    Jacob, Rick E.; Lamm, W. J.

    2011-11-08

    Pulmonary computational fluid dynamics models require 3D images to be acquired over multiple points in the dynamic breathing cycle, with no breath holds or changes in ventilatory mechanics. With small animals, these requirements result in long imaging times ({approx}90 minutes), over which lung mechanics, such as compliance, can gradually change if not carefully monitored and controlled. These changes, caused by derecruitment of parenchymal tissue, are manifested as an upward drift in peak inspiratory pressure or by changes in the pressure waveform and/or lung volume over the course of the experiment. We demonstrate highly repeatable mechanical ventilation in anesthetized rats over a long duration for pulmonary CT imaging throughout the dynamic breathing cycle. We describe significant updates to a basic commercial ventilator that was acquired for these experiments. Key to achieving consistent results was the implementation of periodic deep breaths, or sighs, of extended duration to maintain lung recruitment. In addition, continuous monitoring of breath-to-breath pressure and volume waveforms and long-term trends in peak inspiratory pressure and flow provide diagnostics of changes in breathing mechanics.

  15. Optimizing patient-ventilator synchrony.

    PubMed

    Epstein, S K

    2001-01-01

    Mechanical ventilation assumes the work of breathing, improves gas exchange, and unloads the respiratory muscles, all of which require good synchronization between the patient and the ventilator. Causes for patient-ventilator dyssynchrony include both patient factors (abnormalities of respiratory drive and abnormal respiratory mechanics) and ventilator factors (triggering, flow delivery, breath termination criteria, the level and mode of ventilator support, and imposed work of breathing). Although patient-ventilator dyssynchrony can often be detected on physical exam, careful analysis of ventilator waveforms (pressure-time, flow-time) allows for more precise definition of the underlying cause. Patient-ventilator interaction can be improved by reversing patient factors that alter respiratory drive or elevate patient ventilatory requirements and by correcting factors that contribute to dynamic hyperinflation. Proper setting of the ventilator using sensitive triggering mechanisms, satisfactory flow rates, adequate delivered minute ventilation, matching machine T(I) to neural T(I), and applying modes that overcome the imposed work of breathing, further optimize patient-ventilator synchrony. PMID:16088669

  16. Paradoxical responses to positive end-expiratory pressure in patients with airway obstruction during controlled ventilation*

    PubMed Central

    Caramez, Maria Paula; Borges, Joao B.; Tucci, Mauro R.; Okamoto, Valdelis N.; Carvalho, Carlos R. R.; Kacmarek, Robert M.; Malhotra, Atul; Velasco, Irineu Tadeu; Amato, Marcelo B. P.

    2008-01-01

    Objective To reevaluate the clinical impact of external positive end-expiratory pressure (external-PEEP) application in patients with severe airway obstruction during controlled mechanical ventilation. The controversial occurrence of a paradoxic lung deflation promoted by PEEP was scrutinized. Design External-PEEP was applied stepwise (2 cm H2O, 5-min steps) from zero-PEEP to 150% of intrinsic-PEEP in patients already submitted to ventilatory settings minimizing overinflation. Two commonly used frequencies during permissive hypercapnia (6 and 9/min), combined with two different tidal volumes (VT: 6 and 9 mL/kg), were tested. Setting A hospital intensive care unit. Patients Eight patients were enrolled after confirmation of an obstructive lung disease (inspiratory resistance, >20 cm H2O/L per sec) and the presence of intrinsic-PEEP (≥5 cm H2O) despite the use of very low minute ventilation. Interventions All patients were continuously monitored for intra-arterial blood gas values, cardiac output, lung mechanics, and lung volume with plethysmography. Measurements and Main Results Three different responses to external-PEEP were observed, which were independent of ventilatory settings. In the biphasic response, isovolume-expiratory flows and lung volumes remained constant during progressive PEEP steps until a threshold, beyond which overinflation ensued. In the classic overinflation response, any increment of external-PEEP caused a decrease in isovolume-expiratory flows, with evident overinflation. In the paradoxic response, a drop in functional residual capacity during external-PEEP application (when compared to zero-external-PEEP) was commonly accompanied by decreased plateau pressures and total-PEEP, with increased isovolume-expiratory flows. The paradoxic response was observed in five of the eight patients (three with asthma and two with chronic obstructive pulmonary disease) during at least one ventilator pattern. Conclusions External-PEEP application may

  17. Effects of pressure-controlled and volume-controlled ventilation on respiratory mechanics and systemic stress response during laparoscopic cholecystectomy.

    PubMed

    Sen, Oznur; Umutoglu, Tarik; Aydın, Nurdan; Toptas, Mehmet; Tutuncu, Ayse Cigdem; Bakan, Mefkur

    2016-01-01

    Pressure-controlled ventilation (PCV) is less frequently employed in general anesthesia. With its high and decelerating inspiratory flow, PCV has faster tidal volume delivery and different gas distribution. The same tidal volume setting, delivered by PCV versus volume-controlled ventilation (VCV), will result in a lower peak airway pressure and reduced risk of barotrauma. We hypothesized that PCV instead of VCV during laparoscopic surgery could achieve lower airway pressures and reduce the systemic stress response. Forty ASA I-II patients were randomly selected to receive either the PCV (Group PC, n = 20) or VCV (Group VC, n = 20) during laparoscopic cholecystectomy. Blood sampling was made for baseline arterial blood gases (ABG), cortisol, insulin, and glucose levels. General anesthesia with sevoflurane and fentanyl was employed to all patients. After anesthesia induction and endotracheal intubation, patients in Group PC were given pressure support to form 8 mL/kg tidal volume and patients in Group VC was maintained at 8 mL/kg tidal volume calculated using predicted body weight. All patients were maintained with 5 cmH2O positive-end expiratory pressure (PEEP). Respiratory parameters were recorded before and 30 min after pneumoperitonium. Assessment of ABG and sampling for cortisol, insulin and glucose levels were repeated 30 min after pneumoperitonium and 60 min after extubation. The P-peak levels observed before (18.9 ± 3.8 versus 15 ± 2.2 cmH2O) and during (23.3 ± 3.8 versus 20.1 ± 2.9 cmH2O) pneumoperitoneum in Group VC were significantly higher. Postoperative partial arterial oxygen pressure (PaO2) values are higher (98 ± 12 versus 86 ± 11 mmHg) in Group PC. Arterial carbon dioxide pressure (PaCO2) values (41.8 ± 5.4 versus 36.7 ± 3.5 mmHg) during pneumoperitonium and post-operative mean cortisol and insulin levels were higher in Group VC. When compared to VCV mode, PCV mode may improve compliance during pneumoperitoneum

  18. Driving pressure during assisted mechanical ventilation: Is it controlled by patient brain?

    PubMed

    Georgopoulos, Dimitris; Xirouchaki, Nectaria; Tzanakis, Nikolaos; Younes, Magdy

    2016-07-01

    Tidal volume (VT) is the controlled variable during passive mechanical ventilation (CMV) in order to avoid ventilator-induced-lung-injury. However, recent data indicate that the driving pressure [ΔP; VT to respiratory system compliance (Crs) ratio] is the parameter that best stratifies the risk of death. In order to study which variable (VT or ΔP) is controlled by critically ill patients, 108 previously studied patients were assigned to receive PAV+ (a mode that estimates Crs and permits the patients to select their own breathing pattern) after CMV, were re-analyzed. When patients were switched from CMV to PAV+ they controlled ΔP without constraining VT to narrow limits. VT was increased when the resumption of spontaneous breathing was associated with an increase in Crs. When ΔP was high during CMV, the patients (n=12) decreased it in 58 out of 67 measurements. We conclude that critically ill patients control the driving pressure by sizing the tidal volume to individual respiratory system compliance using appropriate feedback mechanisms aimed at limiting the degree of lung stress. PMID:26994756

  19. Ventilation loss and pressurization in the NASA launch/entry suit: Potential for heat stress

    NASA Technical Reports Server (NTRS)

    Kaufman, Jonathan W.; Dejneka, Katherine Y.; Askew, Gregory K.

    1989-01-01

    The potential of the NASA Launch/Entry Suit (LES) for producing heat stress in a simulated Space Shuttle cabin environment was studied. The testing was designed to identify potential heat stress hazards if the LES were pressurized or if ventilation were lost. Conditions were designed to simulate an extreme pre-launch situation with chamber temperatures maintained at dry bulb temperature = 27.2 +/- 0.1 C, globe temperature = 27.3 +/- 0.1 C, and wet bulb temperature = 21.1 +/- 0.3 C. Two females and two males, 23 to 34 years of age, were employed in this study, with two subjects having exposures in all 3 conditions. Test durations in the ventilated (V) and unventilated (UV) conditions were designed for 480 minutes, which all subjects achieved. Pressurized runs (Pr) were designed for 45 minutes, which all subjects also achieved. While some significant differences related to experimental conditions were noted in rectal and mean skin temperatures, evaporation rates, sweat rates, and heart rate, these differences were not thought to be physiologically significant. The results indicate that the LES garment, in either the Pr or UV state, poses no danger of inducing unacceptable heat stress under the conditions expected within the Space Shuttle cabin during launch or reentry.

  20. Acute respiratory failure induced by mechanical pulmonary ventilation at a peak inspiratory pressure of 40 cmH2O.

    PubMed

    Tsuno, K; Sakanashi, Y; Kishi, Y; Urata, K; Tanoue, T; Higashi, K; Yano, T; Terasaki, H; Morioka, T

    1988-09-01

    The effects of high pressure mechanical pulmonary ventilation at a peak inspiratory pressure of 40 cmH(2)O were studied on the lungs of healthy newborn pigs (14-21 days after birth). Forty percent oxygen in nitrogen was used for ventilation to prevent oxygen intoxication. The control group (6 pigs) was ventilated for 48 hours at a peak inspiratory pressure less than 18 cmH(2)O and a PEEP of 3-5 cmH(2)O with a normal tidal volume, and a respiratory rate of 20 times/min. The control group showed few deleterious changes in the lungs for 48 hours. Eleven newborn pigs were ventilated at a peak inspiratory pressure of 40 cmH(2)O with a PEEP of 3-5 cmH(2)O and a respiratory rate of 20 times/min. To avoid respiratory alkalosis, a dead space was placed in the respiratory circuit, and normocarbia was maintained by adjusting dead space volume. In all cases in the latter group, severe pulmonary impairments, such as abnormal chest roentgenograms, hypoxemia, decreased total static lung compliance, high incidence of pneumothorax, congestive atelectasis, and increased lung weight were found within 48 hours of ventilation. When the pulmonary impairments became manifest, 6 of the 11 newborn pigs were switched to the conventional medical and ventilatory therapies for 3-6 days. However, all of them became ventilator dependent, and severe lung pathology was found at autopsy. These pulmonary insults by high pressure mechanical pulmonary ventilation could be occurring not infrequently in the respiratory management of patients with respiratory failure. PMID:15236077

  1. Dangerous Pressurization and Inappropriate Alarms during Water Occlusion of the Expiratory Circuit of Commonly Used Infant Ventilators

    PubMed Central

    Perdomo, Aldo

    2016-01-01

    Background Non-invasive continuous positive airways pressure is commonly a primary respiratory therapy delivered via multi-purpose ventilators in premature newborns. Expiratory limb occlusion due to water accumulation or ‘rainout’ from gas humidification is a frequent issue. A case of expiratory limb occlusion due to rainout causing unexpected and excessive repetitive airway pressurisation in a Draeger VN500 prompted a systematic bench test examination of currently available ventilators. Objective To assess neonatal ventilator response to partial or complete expiratory limb occlusion when set to non-invasive continuous positive airway pressure mode. Design Seven commercially available neonatal ventilators connected to a test lung using a standard infant humidifier circuit with partial and/or complete expiratory limb occlusion were examined in a bench test study. Each ventilator was set to deliver 6 cmH2O in non-invasive mode and respiratory mechanics data for 75%, 80% and 100% occlusion were collected. Results Several ventilators responded inappropriately with complete occlusion by cyclical pressurisation/depressurisation to peak pressures of between 19·4 and 64·6 cm H2O at rates varying between 2 to 77 inflations per minute. Tidal volumes varied between 10·1 and 24·3mL. Alarm responses varied from ‘specific’ (tube occluded) to ‘ambiguous’ (Safety valve open). Carefusion Avea responded by continuing to provide the set distending pressure and displaying an appropriate alarm message. Draeger Babylog 8000 did not alarm with partial occlusions and incorrectly displayed airways pressure at 6·1cmH2O compared to the measured values of 13cmH2O. Conclusions This study found a potential for significant adverse ventilator response due to complete or near complete expiratory limb occlusion in CPAP mode. PMID:27116224

  2. Non-invasive Positive Pressure Ventilation during Sleep at 3800m: relationship to Acute Mountain Sickness and sleeping oxyhemoglobin saturation

    PubMed Central

    Johnson, PL; Popa, DA; Prisk, GK; Sullivan, CE; Edwards, N

    2014-01-01

    Background and objectives Ascent to high altitude results in hypobaric hypoxia and some individuals will develop Acute Mountain Sickness, which has been shown to be associated with low oxyhemoglobin saturation during sleep. Previous research has shown that positive end-expiratory pressure by use of expiratory valves in a face mask while awake, results in a reduction in AMS symptoms and higher oxyhemoglobin saturation. We aimed to test whether pressure ventilation during sleep would prevent AMS by keeping oxyhaemoglobin higher during sleep. Methods We compared sleeping oxyhemoglobin saturation and the incidence and severity of Acute Mountain Sickness in seven subjects sleeping for two consecutive nights at 3800m above sea level using either non-invasive positive pressure ventilation that delivered positive inspiratory and expiratory airway pressure via a face mask, or sleeping without assisted ventilation. The presence and severity of Acute Mountain Sickness was assessed by administration of the Lake Louise questionnaire. Results We found significant increases in the mean and minimum sleeping oxyhemoglobin saturation and decreases in AMS symptoms in subjects who used positive pressure ventilation during sleep. Mean and minimum sleeping SaO2 was lower in subjects who developed AMS after the night spent without positive pressure ventilation. Conclusion The use of positive pressure ventilation during sleep at 3800m significantly increased the sleeping oxygen saturation; we suggest that the marked reduction in symptoms of AMS is due to this higher sleeping SaO2. We agree with the findings from previous studies that the development of AMS is associated with a lower sleeping oxygen saturation. PMID:20051046

  3. Stable Small Animal Ventilation for Dynamic Lung Imaging to Support Computational Fluid Dynamics Models

    PubMed Central

    Jacob, Richard E.; Lamm, Wayne J.

    2011-01-01

    Pulmonary computational fluid dynamics models require that three-dimensional images be acquired over multiple points in the dynamic breathing cycle without breath holds or changes in ventilatory mechanics. With small animals, these requirements can result in long imaging times (∼90 minutes), over which lung mechanics, such as compliance, may gradually change if not carefully monitored and controlled. These changes, caused by derecruitment of parenchymal tissue, are manifested as an upward drift in peak inspiratory pressure (PIP) or by changes in the pressure waveform and/or lung volume over the course of the experiment. We demonstrate highly repeatable mechanical ventilation in anesthetized rats over a long duration for dynamic lung x-ray computed tomography (CT) imaging. We describe significant updates to a basic commercial ventilator that was acquired for these experiments. Key to achieving consistent results was the implementation of periodic deep breaths, or sighs, of extended duration to maintain lung recruitment. In addition, continuous monitoring of breath-to-breath pressure and volume waveforms and long-term trends in PIP and flow provide diagnostics of changes in breathing mechanics. PMID:22087338

  4. Effect of a downstream ventilated gas cavity on turbulent boundary layer wall pressure fluctuation spectra

    NASA Astrophysics Data System (ADS)

    Young, Steven D.; Brungart, Timothy A.; Lauchle, Gerald C.; Howe, Michael S.

    2005-12-01

    An analytical and experimental investigation is made of the effect of a 2-D ventilated gas cavity on the spectrum of turbulent boundary layer wall pressure fluctuations upstream of a gas cavity on a plane rigid surface. The analytical model predicts the ratio of the wall pressure spectrum in the presence of the cavity to the blocked wall pressure spectrum that would exist if the cavity were absent. The ratio is found to oscillate in amplitude with upstream distance (-x) from the edge of the cavity. It approaches unity as -ωx/Uc-->∞, where ω is the radian frequency and Uc is the upstream turbulence convection velocity. To validate these predictions an experiment was performed in a water tunnel over a range of mean flow velocities. Dynamic wall pressure sensors were flush mounted to a flat plate at various distances upstream from a backward facing step. The cavity was formed downstream of the step by injecting carbon dioxide gas. The water tunnel measurements confirm the predicted oscillatory behavior of the spectral ratio, as well as its relaxation to unity as -ωx/Uc-->∞. For -ωx/Uc>7 the cavity has a negligible influence on the upstream wall pressure fluctuations.

  5. Successful management of H1N1 related severe acute respiratory distress syndrome with noninvasive positive pressure ventilation

    PubMed Central

    Mohamed, Abdulla Ismaeel; Chaari, Anis; Abulfateh, Fatima N.; Alshaikh, Khalid A.; Casey, William Francis

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is a life threatening complication of H1N1 pneumonia. According to the Berlin conference guidelines, severe ARDS requires management with early invasive mechanical ventilation. Whether noninvasive positive pressure ventilation (NIPPV) should be attempted in patients with H1N1 pneumonia is still a matter of debate. We report the case of one patient with severe ARDS without other organ failure. The patient was managed successfully using NIPPV. Endotracheal intubation was avoided and the patient was discharged from the intensive care unit (ICU) after 10 days with a successful outcome. NIPPV can be useful in patients with isolated severe H1N1 ARDS provided early improvement of the oxygenation parameters is achieved. Patients with multiple organ failure or with persistent severe hypoxemia under noninvasive ventilation should be electively intubated and started on invasive mechanical ventilation. PMID:27275488

  6. IMPACT OF VENTILATION FREQUENCY AND PARENCHYMAL STIFFNESS ON FLOW AND PRESSURE DISTRIBUTION IN A CANINE LUNG MODEL

    PubMed Central

    Amini, Reza; Kaczka, David W.

    2013-01-01

    To determine the impact of ventilation frequency, lung volume, and parenchymal stiffness on ventilation distribution, we developed an anatomically-based computational model of the canine lung. Each lobe of the model consists of an asymmetric branching airway network subtended by terminal, viscoelastic acinar units. The model allows for empiric dependencies of airway segment dimensions and parenchymal stiffness on transpulmonary pressure. We simulated the effects of lung volume and parenchymal recoil on global lung impedance and ventilation distribution from 0.1 to 100 Hz, with mean transpulmonary pressures from 5 to 25 cmH2O. With increasing lung volume, the distribution of acinar flows narrowed and became more synchronous for frequencies below resonance. At higher frequencies, large variations in acinar flow were observed. Maximum acinar flow occurred at first antiresonance frequency, where lung impedance achieved a local maximum. The distribution of acinar pressures became very heterogeneous and amplified relative to tracheal pressure at the resonant frequency. These data demonstrate the important interaction between frequency and lung tissue stiffness on the distribution of acinar flows and pressures. These simulations provide useful information for the optimization of frequency, lung volume, and mean airway pressure during conventional ventilation or high frequency oscillation (HFOV). Moreover our model indicates that an optimal HFOV bandwidth exists between the resonant and antiresonant frequencies, for which interregional gas mixing is maximized. PMID:23872936

  7. Continuous endotracheal tube cuff pressure control system protects against ventilator-associated pneumonia

    PubMed Central

    2014-01-01

    Introduction The use of a system for continuous control of endotracheal tube cuff pressure reduced the incidence of ventilator-associated pneumonia (VAP) in one randomized controlled trial (RCT) with 112 patients but not in another RCT with 142 patients. In several guidelines on the prevention of VAP, the use of a system for continuous or intermittent control of endotracheal cuff pressure is not reviewed. The objective of this study was to compare the incidence of VAP in a large sample of patients (n = 284) treated with either continuous or intermittent control of endotracheal tube cuff pressure. Methods We performed a prospective observational study of patients undergoing mechanical ventilation during more than 48 hours in an intensive care unit (ICU) using either continuous or intermittent endotracheal tube cuff pressure control. Multivariate logistic regression analysis (MLRA) and Cox proportional hazard regression analysis were used to predict VAP. The magnitude of the effect was expressed as odds ratio (OR) or hazard ratio (HR), respectively, and 95% confidence interval (CI). Results We found a lower incidence of VAP with the continuous (n = 150) than with the intermittent (n = 134) pressure control system (22.0% versus 11.2%; p = 0.02). MLRA showed that the continuous pressure control system (OR = 0.45; 95% CI = 0.22-0.89; p = 0.02) and the use of an endotracheal tube incorporating a lumen for subglottic secretion drainage (SSD) (OR = 0.39; 95% CI = 0.19-0.84; p = 0.02) were protective factors against VAP. Cox regression analysis showed that the continuous pressure control system (HR = 0.45; 95% CI = 0.24-0.84; p = 0.01) and the use of an endotracheal tube incorporating a lumen for SSD (HR = 0.29; 95% CI = 0.15-0.56; p < 0.001) were protective factors against VAP. However, the interaction between type of endotracheal cuff pressure control system (continuous or intermittent) and endotracheal tube

  8. Clinical evaluation of high-frequency positive-pressure ventilation (HFPPV) in patients scheduled for open-chest surgery.

    PubMed

    Malina, J R; Nordström, S G; Sjöstrand, U H; Wattwil, L M

    1981-05-01

    Comparisons were made in 10 patients scheduled for thoracotomy between a prototype of a low-compressive system (Bronchovent Special) for volume-controlled, high-frequency positive-pressure ventilation (HFPPV; fixed frequency of 60/min; fixed relative insufflation time of 22%), and a conventional respirator (SV-900) for intermittent positive-pressure, volume-controlled ventilation at a frequency of 20/min, after induction of anesthesia, but before surgery. With both ventilator systems intratracheal, intrapleural, systolic, diastolic, and mean arterial systemic and central venous pressures were measured at normoventilation (normocarbia). Mean intratracheal pressure and mean intrapleural pressure were significantly lower with volume-controlled HFPPV (1.3 +/- 0.5 and -4.0 +/- 2.1 (SD) cm H2O, respectively) than with conventional volume-controlled ventilation with SV-900 (2.1 +/- 1.2 and -3.0 +/- 1.5 cm H2O, respectively). No significant differences between the two ventilators were found with respect to arterial systemic and central venous pressures, arterial oxygen and carbon dioxide tensions, or alveolar-arterial oxygen tension difference. With the thorax open, during volume-controlled HFPPV the exposed lung was moderately expanded and exhibited only minor movements during insufflation. Repeated blood gas analyses during surgery showed normocarbia and good oxygenation even during compression of the exposed lung. After compression the lung was readily re-expanded with the aid of a brief period of positive end-expiratory pressure (PEEP). Thus, even relatively low intrapulmonary pressures during volume-controlled HFPPV without PEEP are adequate to keep the open-chest lung expanded during intrathoracic surgery. This creates optimal conditions for the surgeons. PMID:7013568

  9. Literature review supporting assessment of potential radionuclides in the 291-Z exhaust ventilation

    SciTech Connect

    Mahoney, L.A.; Ballinger, M.Y.; Jette, S.J.; Thomas, L.M. Glissmeyer, J.A.; Davis, W.E.

    1994-08-01

    This literature review was prepared to support a study conducted by Pacific Northwest Laboratory to assess the potential deposition and resuspension of radionuclides in the 291-Z ventilation exhaust building located in the 200 West Area of the US Department of Energy`s Hanford Project near Richland, Washington. The filtered ventilation air from three of the facilities at the Plutonium Finishing Plant (PFP) complex are combined together in the 291-Z building before discharge through a common stack. These three facilities contributing filtered exhaust air to the discharge stream are (1) the PFP, also known as the Z-Plant or 234-5Z, (2) the Plutonium Reclamation Facility (PRF or 236-Z), and (3), the Waste Incinerator Building (WIB or 232-Z). The 291-Z building houses the exhaust fans that pull air from the 291-Z central collection plenum and exhausts the air to the stack. Section 2.0 of this report is a description of the physical characteristic of the ventilation system from the High Efficiency Particulate Air (HEPA) filters to the exhaust stack. A description of the processes performed in the facilities that are vented through 291-Z is given in Section 3.0. The description focuses on the chemical and physical forms of potential aerosols given off from the unit operations. A timeline of the operations and events that may have affected the deposition of material in the ventilation system is shown. Aerosol and radiation measurements taken in previous studies are also discussed. Section 4.0 discusses the factors that influence particle deposition and adhesion. Mechanisms of attachment and resuspension are covered with specific attention to the PFP ducts. Conclusions and recommendations are given in Section 5.0.

  10. Mean lung pressure during adult high-frequency oscillatory ventilation: an experimental study using a lung model.

    PubMed

    Hirayama, Takahiro; Nagano, Osamu; Shiba, Naoki; Yumoto, Tetsuya; Sato, Keiji; Terado, Michihisa; Ugawa, Toyomu; Ichiba, Shingo; Ujike, Yoshihito

    2014-12-01

    In adult high-frequency oscillatory ventilation (HFOV), stroke volume (SV) and mean lung pressure (PLung) are important for lung protection. We measured the airway pressure at the Y-piece and the lung pressure during HFOV using a lung model and HFOV ventilators for adults (R100 and 3100B). The lung model was made of a 20-liter, airtight rigid plastic container (adiabatic compliance: 19.3 ml/cmH2O) with or without a resistor (20 cmH2O/l/sec). The ventilator settings were as follows: mean airway pressure (MAP), 30 cmH2O; frequency, 5-15 Hz (every 1 Hz); airway pressure amplitude (AMP), maximum;and % of inspiratory time (IT), 50% for R100, 33% or 50% for 3100B. The measurements were also performed with an AMP of 2/3 or 1/3 maximum at 5, 10 and 15 Hz. The PLung and the measured MAP were not consistently identical to the setting MAP in either ventilator, and decreasing IT decreased the PLung in 3100B. In conclusion, we must pay attention to the possible discrepancy between the PLung and the setting MAP during adult HFOV. PMID:25519026

  11. Autocycling and increase in intrinsic positive end-expiratory pressure during mechanical ventilation.

    PubMed

    Harboe, S; Hjalmarsson, S; Søreide, E

    2001-11-01

    Modern ventilators are complicated electronic instruments with microprocessors and software, with the possibility of technical errors and problems such as autocycling. Despite autocycling being recognized as a problem in textbooks and reviews, there are few reports about autocycling in the literature. We report a case where a sudden increase in respiratory frequency due to autocycling resulted in a dangerous increase in intrinsic positive end-expiratory pressure (intrinsic PEEP, PEEPi). We think our case illustrates that autocycling does occur, but that the exact underlying mechanism may be hard to document and understand for clinicians. To remedy this situation, we suggest that manufacture-independent technical expertise should be established to evaluate incidents and suggest improvements. PMID:11736686

  12. Changes in pulse pressure variability during cardiac resynchronization therapy in mechanically ventilated patients

    PubMed Central

    Keyl, Cornelius; Stockinger, Jochem; Laule, Sven; Staier, Klaus; Schiebeling-Römer, Jochen; Wiesenack, Christoph

    2007-01-01

    Introduction The respiratory variation in pulse pressure (PP) has been established as a dynamic variable of cardiac preload which indicates fluid responsiveness in mechanically ventilated patients. The impact of acute changes in cardiac performance on respiratory fluctuations in PP has not been evaluated until now. We used cardiac resynchronization therapy as a model to assess the acute effects of changes in left ventricular performance on respiratory PP variability without the need of pharmacological intervention. Methods In 19 patients undergoing the implantation of a biventricular pacing/defibrillator device under general anesthesia, dynamic blood pressure regulation was assessed during right ventricular and biventricular pacing in the frequency domain (power spectral analysis) and in the time domain (PP variation: difference between the maximal and minimal PP values, normalized by the mean value). Results PP increased slightly during biventricular pacing but without statistical significance (right ventricular pacing, 33 ± 10 mm Hg; biventricular pacing, 35 ± 11 mm Hg). Respiratory PP fluctuations increased significantly (logarithmically transformed PP variability -1.27 ± 1.74 ln mm Hg2 versus -0.66 ± 1.48 ln mm Hg2; p < 0.01); the geometric mean of respiratory PP variability increased 1.8-fold during cardiac resynchronization. PP variation, assessed in the time domain and expressed as a percentage, showed comparable changes, increasing from 5.3% (3.1%; 12.3%) during right ventricular pacing to 6.9% (4.7%; 16.4%) during biventricular pacing (median [25th percentile; 75th percentile]; p < 0.01). Conclusion Changes in cardiac performance have a significant impact on respiratory hemodynamic fluctuations in ventilated patients. This influence should be taken into consideration when interpreting PP variation. PMID:17445270

  13. The effect of positive end-expiratory pressure on regional ventilation and perfusion in the normal and injured primate lung.

    PubMed

    Hammon, J W; Wolfe, W G; Moran, J F; Jones, R H; Sabiston, D C

    1976-11-01

    Although positive end-expiratory pressure (PEEP) is being employed in the management of respiratory insufficiency, many of its physiological effects remain undetermined. The cardiopulmonary effects of PEEP as well as its effect on regional ventilation and perfusion were studied in 10 baboons before and after pulmonary injury with oleic acid. In the normal lung, there was significant improvement in oxygenation at a PEEP of 5 cm. of water secondary to improved ventilation and perfusion in all PEEP greater than 5 cm. of water produced increasing mismatch of ventilation and perfusion in all zones. After oleic acid was injected, hypoxemia was evident with a reversal of the normal ventilation-perfusion (V/Q) relationship between upper and lower lung zones. This mismatch of ventilation and perfusion was corrected at a PEEP of 15 cm. of water. It was reasonable to conclude that the use of PEEP in the injured lung exerts it beneficial effect by balancing regional ventilation and perfusion in addition to increasing functional residual capacity. PMID:824505

  14. Effects of ventilation with different positive end-expiratory pressures on cytokine expression in the preterm lamb lung.

    PubMed

    Naik, A S; Kallapur, S G; Bachurski, C J; Jobe, A H; Michna, J; Kramer, B W; Ikegami, M

    2001-08-01

    Ventilator-induced lung injury increases proinflammatory cytokines in the adult lung. We asked if positive end-expiratory pressure (PEEP) affects proinflammatory cytokine mRNA expression in the preterm lung. Preterm lambs at 129 +/- 3 d gestation were treated with 100 mg/kg recombinant human surfactant protein-C surfactant and ventilated for 2 or 7 h with 0, 4, or 7 cm H(2)O of PEEP. Unventilated fetal lambs were used as controls. Within 2 h of ventilation, alveolar total protein and activated neutrophils were increased and expression of mRNAs for the proinflammatory cytokines interleukin (IL)-1beta, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) was increased in lung tissue of all ventilated animals relative to unventilated controls. Alveolar protein and neutrophils were higher for 0 and 7 PEEP animals than 4 PEEP animals. IL-1beta, IL-6, and IL-8 mRNAs were significantly elevated in animals ventilated with 0 PEEP compared with 4 PEEP. The percentage fractional area of collapsed alveoli was significantly higher for 0 PEEP compared with 4 and 7 PEEP groups. Mechanical ventilation increased the expression of proinflammatory mediators in surfactant-treated preterm lungs and the use of 4 PEEP minimized this response. PMID:11500356

  15. EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY FOR TOXICS -TBACT- DOUBLE SHELL TANK FARMS PRIMARY VENTILATION SYSTEMS SUPPORTING WASTE TRANSFER OPERATIONS

    SciTech Connect

    HAAS CC; KOVACH JL; KELLY SE; TURNER DA

    2010-06-24

    This report is an evaluation of Best Available Control Technology for Toxics (tBACT) for installation and operation of the Hanford double shell (DST) tank primary ventilation systems. The DST primary ventilation systems are being modified to support Hanford's waste retrieval, mixing, and delivery of single shell tank (SST) and DST waste through the DST storage system to the Waste Treatment and Immobilizaiton Plant (WTP).

  16. EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY FOR TOXICS (TBACT) DOUBLE SHELL TANK FARMS PRIMARY VENTILATION SYSTEM SUPPORTING WASTE TRANSFER OPERATIONS

    SciTech Connect

    KELLY SE; HAASS CC; KOVACH JL; TURNER DA

    2010-06-03

    This report is an evaluation of Best Available Control Technology for Toxics (tBACT) for installation and operation of the Hanford double shell (DST) tank primary ventilation systems. The DST primary ventilation systems are being modified to support Hanford's waste retrieval, mixing, and delivery of single shell tank (SST) and DST waste throught the DST storage system to the Waste Treatment and Immobilization Plant (WTP).

  17. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  18. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  19. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  20. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  1. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  2. Endomicroscopic analysis of time- and pressure-dependent area of subpleural alveoli in mechanically ventilated rats.

    PubMed

    Runck, Hanna; Schwenninger, David; Haberstroh, Jörg; Guttmann, Josef

    2014-11-01

    We investigated the effects of recruitment maneuvers on subpleural alveolar area in healthy rats. 36 mechanically ventilated rats were allocated to either ZEEP-group or PEEP - 5cmH2O - group. The subpleural alveoli were observed using a transthoracal endoscopic imaging technique. Two consecutive low-flow maneuvers up to 30cmH2O peak pressure each were performed, interrupted by 5s plateau phases at four different pressure levels. Alveolar area change at maneuver peak pressures and during the plateau phases was calculated and respiratory system compliance before and after the maneuvers was analyzed. In both groups alveolar area at the second peak of the maneuver did not differ significantly compared to the first peak. During the plateau phases there was a slight increase in alveolar area. After the maneuvers, compliance increased by 30% in ZEEP group and 20% in PEEP group. We conclude that the volume insufflated by the low-flow recruitment maneuver is distributed to deeper but not to subpleural lung regions. PMID:25150503

  3. Ventilator-driven xenon ventilation studies

    SciTech Connect

    Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

    1984-07-01

    A modification of a common commerical Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilator rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration.

  4. Nuclear reactor pressure vessel support system

    DOEpatents

    Sepelak, George R.

    1978-01-01

    A support system for nuclear reactor pressure vessels which can withstand all possible combinations of stresses caused by a postulated core disrupting accident during reactor operation. The nuclear reactor pressure vessel is provided with a flange around the upper periphery thereof, and the flange includes an annular vertical extension formed integral therewith. A support ring is positioned atop of the support ledge and the flange vertical extension, and is bolted to both members. The plug riser is secured to the flange vertical extension and to the top of a radially outwardly extension of the rotatable plug. This system eliminates one joint through which fluids contained in the vessel could escape by making the fluid flow path through the joint between the flange and the support ring follow the same path through which fluid could escape through the plug risers. In this manner, the sealing means to prohibit the escape of contained fluids through the plug risers can also prohibit the escape of contained fluid through the securing joint.

  5. Best Clinical Practices for the Sleep Center Adjustment of Noninvasive Positive Pressure Ventilation (NPPV) in Stable Chronic Alveolar Hypoventilation Syndromes

    PubMed Central

    2010-01-01

    Summary: Noninvasive positive pressure ventilation (NPPV) devices are used during sleep to treat patients with diurnal chronic alveolar hypoventilation (CAH). Bilevel positive airway pressure (BPAP) using a mask interface is the most commonly used method to provide ventilatory support in these patients. BPAP devices deliver separately adjustable inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP). The IPAP and EPAP levels are adjusted to maintain upper airway patency, and the pressure support (PS = IPAP-EPAP) augments ventilation. NPPV devices can be used in the spontaneous mode (the patient cycles the device from EPAP to IPAP), the spontaneous timed (ST) mode (a backup rate is available to deliver IPAP for the set inspiratory time if the patient does not trigger an IPAP/EPAP cycle within a set time window), and the timed (T) mode (inspiratory time and respiratory rate are fixed). During NPPV titration with polysomnography (PSG), the pressure settings, backup rate, and inspiratory time (if applicable) are adjusted to maintain upper airway patency and support ventilation. However, there are no widely available guidelines for the titration of NPPV in the sleep center. A NPPV Titration Task Force of the American Academy of Sleep Medicine reviewed the available literature and developed recommendations based on consensus and published evidence when available. The major recommendations derived by this consensus process are as follows: General Recommendations:The indications, goals of treatment, and side effects of NPPV treatment should be discussed in detail with the patient prior to the NPPV titration study.Careful mask fitting and a period of acclimatization to low pressure prior to the titration should be included as part of the NPPV protocol.NPPV titration with PSG is the recommended method to determine an effective level of nocturnal ventilatory support in patients with CAH. In circumstances in which NPPV treatment is initiated

  6. Nocturnal respiratory failure in a child with congenital myopathy – management using average volume-assured pressure support (AVAPS)

    PubMed Central

    Gentin, Natalie; Williamson, Bruce; Thambipillay, Ganesh; Teng, Arthur

    2015-01-01

    This is a case report of the effective use of bi-level positive airway pressure support (BPAP) using the volume-assured pressure support feature in a pediatric patient with a congenital myopathy and significant nocturnal hypoventilation. Our patient was started on nocturnal nasal mask BPAP but required high pressures to improve her oxygen saturations and CO2 baseline. She was then trialed on a BPAP machine with the volume-assured pressure support feature on. The ability of this machine to adjust inspiratory pressures to give a targeted tidal volume allowed the patient to be on lower pressure settings for periods of the night, with the higher pressures only when required. She tolerated the ventilation well and her saturations, CO2 profiles, and clinical condition improved. This case report highlights the benefits of the volume-assured pressure support feature on a BPAP machine in a child with a neuromuscular disorder. PMID:26392861

  7. Heart rate variability and stroke volume variability to detect central hypovolemia during spontaneous breathing and supported ventilation in young, healthy volunteers.

    PubMed

    Elstad, Maja; Walløe, Lars

    2015-04-01

    Cardiovascular oscillations exist in many different variables and may give important diagnostic and prognostic information in patients. Variability in cardiac stroke volume (SVV) is used in clinical practice for diagnosis of hypovolemia, but currently is limited to patients on mechanical ventilation. We investigated if SVV and heart rate variability (HRV) could detect central hypovolemia in spontaneously breathing humans: We also compared cardiovascular variability during spontaneous breathing with supported mechanical ventilation.Ten subjects underwent simulated central hypovolemia by lower body negative pressure (LBNP) with >10% reduction of cardiac stroke volume. The subjects breathed spontaneously and with supported mechanical ventilation. Heart rate, respiratory frequency and mean arterial blood pressure were measured. Stroke volume (SV) was estimated by ModelFlow (Finometer). Respiratory SVV was calculated by: 1) SVV% = (SVmax - SVmin)/SVmean during one respiratory cycle, 2) SVIntegral from the power spectra (Fourier transform) at 0.15-0.4 Hz and 3) SVV_norm = (√SVIntegral)/SVmean. HRV was calculated by the same methods.During spontaneous breathing two measures of SVV and all three measures of HRV were reduced during hypovolemia compared to baseline. During spontaneous breathing SVIntegral and HRV% were best to detect hypovolemia (area under receiver operating curve 0.81). HRV% ≤ 11% and SVIntegral ≤ 12 ml(2) differentiated between hypovolemia and baseline during spontaneous breathing.During supported mechanical ventilation, none of the three measures of SVV changed and two of the HRV measures were reduced during hypovolemia. Neither measures of SVV nor HRV were classified as a good detector of hypovolemia.We conclude that HRV% and SVIntegral detect hypovolemia during spontaneous breathing and both are candidates for further clinical testing. PMID:25799094

  8. Ventilators for noninvasive ventilation to treat acute respiratory failure.

    PubMed

    Scala, Raffaele; Naldi, Mario

    2008-08-01

    The application of noninvasive ventilation (NIV) to treat acute respiratory failure has increased tremendously both inside and outside the intensive care unit. The choice of ventilator is crucial for success of NIV in the acute setting, because poor tolerance and excessive air leaks are significantly correlated with NIV failure. Patient-ventilator asynchrony and discomfort can occur if the physician or respiratory therapist fails to adequately set NIV to respond to the patient's ventilatory demand, so clinicians need to fully understood the ventilator's technical peculiarities (eg, efficiency of trigger and cycle systems, speed of pressurization, air-leak compensation, CO(2) rebreathing, reliability of fraction of inspired oxygen reading, monitoring accuracy). A wide range of ventilators of different complexity have been introduced into clinical practice to noninvasively support patients in acute respiratory failure, but the numerous commercially available ventilators (bi-level, intermediate, and intensive care unit ventilators) have substantial differences that can influence patient comfort, patient-ventilator interaction, and, thus, the chance of NIV clinical success. This report examines the most relevant aspects of the historical evolution, the equipment, and the acute-respiratory-failure clinical application of NIV ventilators. PMID:18655744

  9. Flexible bronchoscopy during non-invasive positive pressure mechanical ventilation: are two better than one?

    PubMed

    Scala, Raffaele

    2016-09-01

    Flexible bronchoscopy (FBO) and non-invasive positive pressure ventilation (NIPPV) are largely applied in respiratory and general intensive care units. FBO plays a crucial role for the diagnosis of lung infiltrates of unknown origin and for the treatment of airways obstruction due to bronchial mucous plugging and hemoptysis in critical patients. NIPPV is the first-choice ventilatory strategy for acute respiratory failure (ARF) of different causes as it could be used as prevention or as alternative to the conventional mechanical ventilation (CMV) via endotracheal intubation (ETI). Some clinical scenarios represent contraindications for these techniques such as severe ARF in spontaneous breathing patients for FBO and accumulated tracheo-bronchial secretions in patients with depressed cough for NIPPV. In these contexts, the decision of performing ETI should carefully consider the risk of CMV-correlated complications. An increasing amount of published data suggested the use of FBO during NIPPV in ARF in order to avoid/reduce the need of ETI. Despite a strong rationale for the combined use of the two techniques, there is not still enough evidence for a large-scale application of this strategy in all different clinical scenarios. The majority of the available data are in favor of the "help" given by NIPPV to diagnostic FBO in high-risk spontaneously breathing patients with severe hypoxemia. Preliminary findings report the successful "help" given by early FBO to NIPPV in patients with hypoxemic-hypercapnic ARF who are likely to fail because of hypersecretion. Synergy of FBO and NIPPV application is emerging also to perform ETI in challenging situations, such as predicted difficult laringoscopy and NPPV failure in severely hypoxemic patients. This combined approach should be performed only in centers showing a wide experience with both NIPPV and FBO, where close monitoring and ETI facilities are promptly available. PMID:27012292

  10. Cardiopulmonary effects of hypercapnia during controlled intermittent positive pressure ventilation in the horse.

    PubMed Central

    Khanna, A K; McDonell, W N; Dyson, D H; Taylor, P M

    1995-01-01

    The cardiopulmonary effects of eucapnia (arterial CO2 tension [PaCO2] 40.4 +/- 2.9 mm Hg, mean +/- SD), mild hypercapnia (PaCO2, 59.1 +/- 3.5 mm Hg), moderate hypercapnia (PaCO2, 82.6 +/- 4.9 mm Hg), and severe hypercapnia (PaCO2, 110.3 +/- 12.2 mm Hg) were studied in 8 horses during isoflurane anesthesia with volume controlled intermittent positive pressure ventilation (IPPV) and neuromuscular blockade. The sequence of changes in PaCO2 was randomized. Mild hypercapnia produced bradycardia resulting in a significant (P < 0.05) decrease in cardiac index (CI) and oxygen delivery (DO2), while hemoglobin concentration (Hb), the hematocrit (Hct), systolic blood pressure (SBP), mean blood pressure (MBP), systemic vascular resistance (SVR), and venous admixture (QS/QT) increased significantly. Moderate hypercapnia resulted in a significant rise in CI, stroke index (SI), SBP, MBP, mean pulmonary artery pressure (PAP), Hct, Hb, arterial oxygen content (CaO2), mixed venous oxygen content (CvO2), and DO2, with heart rate (HR) staying below eucapnic levels. Severe hypercapnia resulted in a marked rise in HR, CI, SI, SBP, PAP, Hct, Hb, CaO2, CvO2, and DO2. Systemic vascular resistance was significantly decreased, while MBP levels were not different from those during moderate hypercapnia. No cardiac arrhythmias were recorded with any of the ranges of PaCO2. Norepinephrine levels increased progressively with each increase in PaCO2, whereas plasma cortisol levels remained unchanged. It was concluded that hypercapnia in isoflurane-anesthetized horses elicits a biphasic cardiopulmonary response, with mild hypercapnia producing a fall in CI and DO2 despite an increase in MBP, while moderate and severe hypercapnia produce an augmentation of the cardiopulmonary performance and DO2. PMID:8521355

  11. Update: Non-Invasive Positive Pressure Ventilation in Chronic Respiratory Failure Due to COPD.

    PubMed

    Altintas, Nejat

    2016-01-01

    Long-term non-invasive positive pressure ventilation (NPPV) has widely been accepted to treat chronic hypercapnic respiratory failure arising from different etiologies. Although the survival benefits provided by long-term NPPV in individuals with restrictive thoracic disorders or stable, slowly-progressing neuromuscular disorders are overwhelming, the benefits provided by long-term NPPV in patients with chronic obstructive pulmonary disease (COPD) remain under question, due to a lack of convincing evidence in the literature. In addition, long-term NPPV reportedly failed in the classic trials to improve important physiological parameters such as arterial blood gases, which might serve as an explanation as to why long-term NPPV has not been shown to substantially impact on survival. However, high intensity NPPV (HI-NPPV) using controlled NPPV with the highest possible inspiratory pressures tolerated by the patient has recently been described as a new and promising approach that is well-tolerated and is also capable of improving important physiological parameters such as arterial blood gases and lung function. This clearly contrasts with the conventional approach of low-intensity NPPV (LI-NPPV) that uses considerably lower inspiratory pressures with assisted forms of NPPV. Importantly, HI-NPPV was very recently shown to be superior to LI-NPPV in terms of improved overnight blood gases, and was also better tolerated than LI-NPPV. Furthermore, HI-NPPV, but not LI-NPPV, improved dyspnea, lung function and disease-specific aspects of health-related quality of life. A recent study showed that long-term treatment with NPPV with increased ventilatory pressures that reduced hypercapnia was associated with significant and sustained improvements in overall mortality. Thus, long-term NPPV seems to offer important benefits in this patient group, but the treatment success might be dependent on effective ventilatory strategies. PMID:26418151

  12. [Successful perioperative use of noninvasive positive pressure ventilation in a pregnant woman with acute pulmonary edema].

    PubMed

    Fujita, Naoko; Tachibana, Kazuya; Takeuchi, Muneyuki; Kinouchi, Keiko

    2014-05-01

    A 32-year-old woman (148 cm, 59 kg, gravida 2, para 2) with quadruplet pregnancy was admitted to our hospital for the threatened preterm labor at 23 weeks and 2 days of gestation. She was treated with ritodrine, magnesium sulfate and nifedipine to maintain tocolysis. Betamethasone was administered to accelerate fetal lung maturity. After ritodrine dose was increased at 23 weeks and 5 days of gestation, she developed dyspnea with desaturation. Acute pulmonary edema was revealed on chest X-ray. The decision was made to proceed with emergency cesarean delivery. On arrival at the operating room, the blood pressure was 123/53 mmHg, heart rate 111 beats x min(-1), and oxygen saturation (SpO2) 84% with supplemental oxygen 15 l x min(-1) via a reserved face mask. Noninvasive positive pressure ventilation (NPPV) was initiated with S/T mode (FIO2 1.0, inspiratory positive airway pressure 10 cmH2O, expiratory positive airway pressure 6 cmH2O). The dyspnea was improved with her SpO2 100%. Spinal anesthesia was performed at L 34 using 2.5 ml of 0.5% bupivacaine and 100 microg morphine. Throughout the operation (operation time 44 minutes), she did not develop dyspnea under NPPV. NPPV was discontinued after the operation. Her SpO2 declined, and pulmonary edema on chest X-ray was exacerbated. She was transferred to the intensive care unit and NPPV was continued for 22 hours after the operation. She was discharged from the intensive care unit on the next day and was discharged from the hospital on the 6th postoperative day. PMID:24864580

  13. Blood pressure management in mechanical circulatory support

    PubMed Central

    Adatya, Sirtaz

    2015-01-01

    Durable mechanical support has become widely available for end stage heart failure as destination therapy and as bridge to transplantation. The accurate measurement of blood pressure (BP) as well as the recognition and management of hypertension in patients with continuous flow left ventricular assist devices (CF-VADs) is an essential component of optimal clinical care. Strategies for the control of BP in CF-VAD patients are increasingly important as there is an evolving understanding of the connection between hypertension, pump output, and adverse outcomes. As clinical experience grows, optimal BP targets, as well as methods to measure BP in CF-VAD patients have been further defined. PMID:26793332

  14. Chemotherapy for a ventilator-supported patient with small cell lung cancer: A case report

    PubMed Central

    Xiang, Run; Xie, Tianpeng; Li, Qiang

    2016-01-01

    Small cell lung cancer (SCLC) is common in thoracic neoplasms, with a high degree of malignancy and rapid tumor progression. SCLC is often diagnosed with widespread metastases at the time of the initial diagnosis. A small proportion of late-stage SCLC patients are in a poor physical condition and exhibit disqualifying chemoradiotherapy indications. The present study reports the case of a patient who presented with lumbago and backache. Following physical examination, computed tomography, bronchoscopy and biopsy, the patient was diagnosed with SCLC with an Eastern Cooperative Oncology Group score of <2. One cycle of chemotherapy was administered whilst ventilator support was provided, and the patient's condition eventually improved. However, the patient finally succumbed to respiratory failure at 10 months post-diagnosis. PMID:27602149

  15. Bi-level positive airway pressure (BiPAP) ventilation in an infant with central hypoventilation syndrome.

    PubMed

    Villa, M P; Dotta, A; Castello, D; Piro, S; Pagani, J; Palamides, S; Ronchetti, R

    1997-07-01

    A 4-month-old baby girl, after a period of apparent good health, began to have aphonia, dyspnea, difficulties with swallowing, cyanosis, apnea, and hypopnea during sleep that resulted in admission to an intensive care unit for intubation and mechanical ventilation. At the age of 9 months she was admitted to our hospital with a possible diagnosis of central hypoventilation syndrome. A polysomnographic study showed apnea and hypopnea (apnea + hypopnea index = 47.1), hypercapnia (mean end-tidal PCO2 89 +/- 15.0 mmHg), and arterial desaturation (mean SaO2 91 +/- 1.7%; lowest SaO2 < 50%; 68% of total sleep time at SaO2 below 93%); the study also showed an absent ventilatory response to CO2, absent cardiac responses to apnea during sleep, and right ventricular hypertrophy. Nocturnal nasal bi-level positive airway pressure (BIPAP), applied initially at 6 cmH2O and gradually increased to 16 cmH2O, caused the sleep-related abnormal respiratory events to disappear. End-tidal PCO2 decreased to 39 mmHg, and SaO2 increased to 94%. After 6 months of nocturnal BiPAP ventricular right hypertrophy reversed and arrested growth and hypotonia normalized. The child has tolerated and has remained on BiPAP support up to her current age of 3 years and continues to use this form of ventilatory assistance without difficulties. PMID:9261857

  16. Intermittent negative pressure ventilation in the treatment of hypoxic hypercapnic coma in chronic respiratory insufficiency.

    PubMed Central

    Corrado, A; De Paola, E; Gorini, M; Messori, A; Bruscoli, G; Nutini, S; Tozzi, D; Ginanni, R

    1996-01-01

    BACKGROUND: In recent years non-invasive ventilatory techniques have been used successfully in the treatment of acute on chronic respiratory failure (ACRF), but careful selection of patients is essential and a comatose state may represent an exclusion criterion. The aim of this retrospective and uncontrolled study was to evaluate whether a non-invasive ventilatory technique such as the iron lung could also be used successfully in patients with hypoxic hypercapnic coma, thus widening the range for application of non-invasive ventilatory techniques. METHODS: A series of 150 consecutive patients with ACRF and hypoxic hypercapnic coma admitted to our respiratory intensive care unit were evaluated retrospectively. The most common underlying condition was chronic obstructive pulmonary disease (79%). On admission a severe hypoxaemia (Pao2 5.81 (3.01) kPa) and hypercapnia (Paco2 14.88 (2.78) kPa) associated with a decompensated acidosis (pH 7.13 (0.13)) were present, the Glasgow coma score ranged from 3 to 8, and the mean APACHE II score was 31.6 (5.3). All patients underwent intermittent negative pressure ventilation with the iron lung. The study end point was based on a dichotomous classification of treatment failure (defined as death or need for endotracheal intubation) versus therapeutic success. RESULTS: There were 45 treatment failures (30%) and 36 deaths (24%). Nine patients (6%) required intubation because of lack of airway control. The median total duration of ventilation was 27 hours per patient (range 2-274). The 105 successfully treated cases recovered consciousness after a median of four hours (range 1-90) of continuous ventilatory treatment and were discharged after 12.1 (9.0) days. CONCLUSIONS: These results show that, in patients with acute on chronic respiratory failure and hypoxic hypercapnic coma, the iron lung resulted in a high rate of success. As this study has the typical limitations of all retrospective and uncontrolled studies, the results need to

  17. Intraoperative protective mechanical ventilation for prevention of postoperative pulmonary complications: a comprehensive review of the role of tidal volume, positive end-expiratory pressure, and lung recruitment maneuvers.

    PubMed

    Güldner, Andreas; Kiss, Thomas; Serpa Neto, Ary; Hemmes, Sabrine N T; Canet, Jaume; Spieth, Peter M; Rocco, Patricia R M; Schultz, Marcus J; Pelosi, Paolo; Gama de Abreu, Marcelo

    2015-09-01

    Postoperative pulmonary complications are associated with increased morbidity, length of hospital stay, and mortality after major surgery. Intraoperative lung-protective mechanical ventilation has the potential to reduce the incidence of postoperative pulmonary complications. This review discusses the relevant literature on definition and methods to predict the occurrence of postoperative pulmonary complication, the pathophysiology of ventilator-induced lung injury with emphasis on the noninjured lung, and protective ventilation strategies, including the respective roles of tidal volumes, positive end-expiratory pressure, and recruitment maneuvers. The authors propose an algorithm for protective intraoperative mechanical ventilation based on evidence from recent randomized controlled trials. PMID:26120769

  18. The use of equine surfactant and positive pressure ventilation to treat a premature alpaca cria with severe hypoventilation and hypercapnia

    PubMed Central

    Tinkler, Stacy H.; Mathews, Lindsey A.; Firshman, Anna M.; Quandt, Jane E.

    2015-01-01

    A 5-hour-old, premature alpaca cria was presented with failure to nurse, weakness, hypoglycemia, hypercapnia, and respiratory distress. The cria was treated with 3 doses of fresh, crude equine surfactant, positive pressure ventilation, and supplemental intranasal oxygen. Recovery to discharge was uneventful, and the cria regained apparently normal respiratory function. Three years after hospital discharge, the alpaca was a healthy adult. PMID:25829556

  19. The use of equine surfactant and positive pressure ventilation to treat a premature alpaca cria with severe hypoventilation and hypercapnia.

    PubMed

    Tinkler, Stacy H; Mathews, Lindsey A; Firshman, Anna M; Quandt, Jane E

    2015-04-01

    A 5-hour-old, premature alpaca cria was presented with failure to nurse, weakness, hypoglycemia, hypercapnia, and respiratory distress. The cria was treated with 3 doses of fresh, crude equine surfactant, positive pressure ventilation, and supplemental intranasal oxygen. Recovery to discharge was uneventful, and the cria regained apparently normal respiratory function. Three years after hospital discharge, the alpaca was a healthy adult. PMID:25829556

  20. Ventilation Model

    SciTech Connect

    H. Yang

    1999-11-04

    The purpose of this analysis and model report (AMR) for the Ventilation Model is to analyze the effects of pre-closure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts and provide heat removal data to support EBS design. It will also provide input data (initial conditions, and time varying boundary conditions) for the EBS post-closure performance assessment and the EBS Water Distribution and Removal Process Model. The objective of the analysis is to develop, describe, and apply calculation methods and models that can be used to predict thermal conditions within emplacement drifts under forced ventilation during the pre-closure period. The scope of this analysis includes: (1) Provide a general description of effects and heat transfer process of emplacement drift ventilation. (2) Develop a modeling approach to simulate the impacts of pre-closure ventilation on the thermal conditions in emplacement drifts. (3) Identify and document inputs to be used for modeling emplacement ventilation. (4) Perform calculations of temperatures and heat removal in the emplacement drift. (5) Address general considerations of the effect of water/moisture removal by ventilation on the repository thermal conditions. The numerical modeling in this document will be limited to heat-only modeling and calculations. Only a preliminary assessment of the heat/moisture ventilation effects and modeling method will be performed in this revision. Modeling of moisture effects on heat removal and emplacement drift temperature may be performed in the future.

  1. Ventilator-driven xenon ventilation studies

    SciTech Connect

    Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

    1984-07-01

    A modification of a common commercial Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilatory rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration.

  2. Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients

    PubMed Central

    Cannesson, Maxime; Besnard, Cyril; Durand, Pierre G; Bohé, Julien; Jacques, Didier

    2005-01-01

    Introduction Respiratory variation in arterial pulse pressure is a reliable predictor of fluid responsiveness in mechanically ventilated patients with circulatory failure. The main limitation of this method is that it requires an invasive arterial catheter. Both arterial and pulse oximetry plethysmographic waveforms depend on stroke volume. We conducted a prospective study to evaluate the relationship between respiratory variation in arterial pulse pressure and respiratory variation in pulse oximetry plethysmographic (POP) waveform amplitude. Method This prospective clinical investigation was conducted in 22 mechanically ventilated patients. Respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude were recorded simultaneously in a beat-to-beat evaluation, and were compared using a Spearman correlation test and a Bland–Altman analysis. Results There was a strong correlation (r2 = 0.83; P < 0.001) and a good agreement (bias = 0.8 ± 3.5%) between respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude. A respiratory variation in POP waveform amplitude value above 15% allowed discrimination between patients with respiratory variation in arterial pulse pressure above 13% and those with variation of 13% or less (positive predictive value 100%). Conclusion Respiratory variation in arterial pulse pressure above 13% can be accurately predicted by a respiratory variation in POP waveform amplitude above 15%. This index has potential applications in patients who are not instrumented with an intra-arterial catheter. PMID:16277719

  3. A historical perspective on ventilator management.

    PubMed

    Shapiro, B A

    1994-02-01

    Paralysis via neuromuscular blockade in ICU patients requires mechanical ventilation. This review historically addresses the technological advances and scientific information upon which ventilatory management concepts are based, with special emphasis on the influence such concepts have had on the use of neuromuscular blocking agents. Specific reference is made to the scientific information and technological advances leading to the newer concepts of ventilatory management. Information from > 100 major studies in the peer-reviewed medical literature, along with the author's 25 yrs of clinical experience and academic involvement in acute respiratory care is presented. Nomenclature related to ventilatory management is specifically defined and consistently utilized to present and interpret the data. Pre-1970 ventilatory management is traced from the clinically unacceptable pressure-limited devices to the reliable performance of volume-limited ventilators. The scientific data and rationale that led to the concept of relatively large tidal volume delivery are reviewed in the light of today's concerns regarding alveolar overdistention, control-mode dyssynchrony, and auto-positive end-expiratory pressure. Also presented are the post-1970 scientific rationales for continuous positive airway pressure/positive end-expiratory pressure therapy, avoidance of alveolar hyperxia, and partial ventilatory support techniques (intermittent mandatory ventilation/synchronized intermittent mandatory ventilation). The development of pressure-support devices is discussed and the capability of pressure-control techniques is presented. The rationale for more recent concepts of total ventilatory support to avoid ventilator-induced lung injury is presented. The traditional techniques utilizing volume-preset ventilators with relatively large tidal volumes remain valid and desirable for the vast majority of patients requiring mechanical ventilation. Neuromuscular blockade is best avoided in these

  4. Building a Comprehensive System of Services to Support Adults Living with Long-Term Mechanical Ventilation

    PubMed Central

    Leasa, David; Elson, Stephen

    2016-01-01

    Background. Increasing numbers of individuals require long-term mechanical ventilation (LTMV) in the community. In the South West Local Health Integration Network (LHIN) in Ontario, multiple organizations have come together to design, build, and operate a system to serve adults living with LTMV. Objective. The goal was to develop an integrated approach to meet the health and supportive care needs of adults living with LTMV. Methods. The project was undertaken in three phases: System Design, Implementation Planning, and Implementation. Results. There are both qualitative and quantitative evidences that a multiorganizational system of care is now operational and functioning in a way that previously did not exist. An Oversight Committee and an Operations Management Committee currently support the system of services. A Memorandum of Understanding has been signed by the participating organizations. There is case-based evidence that hospital admissions are being avoided, transitions in care are being thoughtfully planned and executed collaboratively among service providers, and new roles and responsibilities are being accepted within the overall system of care. Conclusion. Addressing the complex and variable needs of adults living with LTMV requires a systems response involving the full continuum of care. PMID:27445527

  5. Building a Comprehensive System of Services to Support Adults Living with Long-Term Mechanical Ventilation.

    PubMed

    Leasa, David; Elson, Stephen

    2016-01-01

    Background. Increasing numbers of individuals require long-term mechanical ventilation (LTMV) in the community. In the South West Local Health Integration Network (LHIN) in Ontario, multiple organizations have come together to design, build, and operate a system to serve adults living with LTMV. Objective. The goal was to develop an integrated approach to meet the health and supportive care needs of adults living with LTMV. Methods. The project was undertaken in three phases: System Design, Implementation Planning, and Implementation. Results. There are both qualitative and quantitative evidences that a multiorganizational system of care is now operational and functioning in a way that previously did not exist. An Oversight Committee and an Operations Management Committee currently support the system of services. A Memorandum of Understanding has been signed by the participating organizations. There is case-based evidence that hospital admissions are being avoided, transitions in care are being thoughtfully planned and executed collaboratively among service providers, and new roles and responsibilities are being accepted within the overall system of care. Conclusion. Addressing the complex and variable needs of adults living with LTMV requires a systems response involving the full continuum of care. PMID:27445527

  6. The growing role of noninvasive ventilation in patients requiring prolonged mechanical ventilation.

    PubMed

    Hess, Dean R

    2012-06-01

    For many patients with chronic respiratory failure requiring ventilator support, noninvasive ventilation (NIV) is preferable to invasive support by tracheostomy. Currently available evidence does not support the use of nocturnal NIV in unselected patients with stable COPD. Several European studies have reported benefit for high intensity NIV, in which setting of inspiratory pressure and respiratory rate are selected to achieve normocapnia. There have also been studies reporting benefit for the use of NIV as an adjunct to exercise training. NIV may be useful as an adjunct to airway clearance techniques in patients with cystic fibrosis. Accumulating evidence supports the use of NIV in patients with obesity hypoventilation syndrome. There is considerable observational evidence supporting the use of NIV in patients with chronic respiratory failure related to neuromuscular disease, and one randomized controlled trial reported that the use of NIV was life-prolonging in patients with amyotrophic lateral sclerosis. A variety of interfaces can be used to provide NIV in patients with stable chronic respiratory failure. The mouthpiece is an interface that is unique in this patient population, and has been used with success in patients with neuromuscular disease. Bi-level pressure ventilators are commonly used for NIV, although there are now a new generation of intermediate ventilators that are portable, have a long battery life, and can be used for NIV and invasive applications. Pressure support ventilation, pressure controlled ventilation, and volume controlled ventilation have been used successfully for chronic applications of NIV. New modes have recently become available, but their benefits await evidence to support their widespread use. The success of NIV in a given patient population depends on selection of an appropriate patient, selection of an appropriate interface, selection of an appropriate ventilator and ventilator settings, the skills of the clinician, the

  7. The Effect of Equal Ratio Ventilation on Oxygenation, Respiratory Mechanics, and Cerebral Perfusion Pressure During Laparoscopy in the Trendelenburg Position.

    PubMed

    Jo, Youn Yi; Kim, Ji Young; Chang, Young Jin; Lee, Sehwan; Kwak, Hyun Jeong

    2016-06-01

    The aim of this study was to investigate the effects of equal ratio ventilation (ERV) on oxygenation, respiratory mechanics, and the cerebral perfusion pressure during pneumoperitoneum in the Trendelenburg position. Thirty patients undergoing laparoscopic low anterior resection (25 to 65 y) were enrolled. Mechanical ventilator was set to volume-controlled mode at an inspiratory to expiratory (I:E) ratio of 1:2 with a tidal volume of 8 mL/kg of ideal body weight with a 5 cm H2O positive end-expiratory pressure. Twenty minutes after pneumoperitoneum in the Trendelenburg position, the I:E ratio was changed to 1:1 for 20 minutes and then restored to 1:2. No significant changes in arterial oxygen tension and respiratory compliance after adopting ERV. Mean arterial pressure and cerebral perfusion pressure decreased significantly over time after adopting the Trendelenburg position during pneumoperitoneum (P=0.014 and 0.005, respectively). In conclusion, there was no improvement in oxygenation or respiratory mechanics with ERV. PMID:27258912

  8. Myasthenia gravis: determinants for independent ventilation after transsternal thymectomy.

    PubMed

    Younger, D S; Braun, N M; Jaretzki, A; Penn, A S; Lovelace, R E

    1984-03-01

    We evaluated the respiratory function of 32 patients with myasthenia gravis who had transsternal thymectomy. Preoperative clinical, pulmonary function, and respiratory muscle pressure data were submitted to stepwise logistic regression analysis to identify preoperative factors that correlated with duration of supported ventilation after surgery. Ten patients (31%) had postoperative supported ventilation for more than 3 days. The duration of ventilatory support correlated most closely with maximal static expiratory pressure (r = 0.714, p less than 0.001). Expiratory weakness, by reducing cough efficacy, seems to be the main determinant that predicts need for longer postoperative supported ventilation. PMID:6538272

  9. VENTILATION NEEDS DURING CONSTRUCTION

    SciTech Connect

    C.R. Gorrell

    1998-07-23

    The purpose of this analysis is to determine ventilation needs during construction and development of the subsurface repository and develop systems to satisfy those needs. For this analysis, construction is defined as pre-emplacement excavation and development is excavation that takes place simultaneously with emplacement. The three options presented in the ''Overall Development and Emplacement Ventilation Systems'' analysis (Reference 5.5) for development ventilation will be applied to construction ventilation in this analysis as well as adding new and updated ventilation factors to each option for both construction and development. The objective of this analysis is to develop a preferred ventilation system to support License Application Design. The scope of this analysis includes: (1) Description of ventilation conditions; (2) Ventilation factors (fire hazards, dust control, construction logistics, and monitoring and control systems); (3) Local ventilation alternatives; (4) Global ventilation options; and (5) Evaluation of options.

  10. The effect of mechanical ventilator settings during ventilator hyperinflation techniques: a bench-top analysis.

    PubMed

    Thomas, P J

    2015-01-01

    Ventilator hyperinflations are used by physiotherapists for the purpose of airway clearance in intensive care. There is limited data to guide the selection of mechanical ventilator modes and settings that may achieve desired flow patterns for ventilator hyperinflation. A mechanical ventilator was connected to two lung simulators and a respiratory mechanics monitor. Peak inspiratory (PIFR) and expiratory flow rates (PEFR) were measured during manipulation of ventilator modes (pressure support ventilation [PSV], volume-controlled synchronised intermittent mandatory ventilation [VC-SIMV] and pressure-controlled synchronised intermittent mandatory ventilation [PC-SIMV]) and ventilator settings (including set tidal volume, positive end-expiratory pressure, inspiratory flow rate, inspiratory pause, pressure support, inspiratory time and/or inflation pressure). Additionally, each trial was conducted with high (0.05 l/cmH2O) and low (0.01 l/cmH2O) compliance settings on the lung simulators. Each trial was dichotomised into success or failure under three categories (attainment of PIFR-PEFR less than or equal to 0.9, PEFR/PIFR greater than 17 l/min, PEFR greater than or equal to 40 l/min). A total of 232 trials were conducted (96 VC-SIMV, 96 PC-SIMV, 40 PSV). A greater proportion of VC-SIMV trials were ceased due to high peak inspiratory pressures (35%). However, VC-SIMV trials were more likely to be successful at meeting all three outcome measures (26 VC-SIMV trials, 7 PC-SIMV trials, 0 PSV trials). It was found that manipulation of settings in VC-SIMV mode appears more successful than PSV and PC-SIMV for ventilator hyperinflations. PMID:25579293

  11. Initial Treatment of Respiratory Distress Syndrome with Nasal Intermittent Mandatory Ventilation versus Nasal Continuous Positive Airway Pressure: A Randomized Controlled Trial

    PubMed Central

    Armanian, Amir-Mohammad; Badiee, Zohreh; Heidari, Ghobad; Feizi, Awat; Salehimehr, Nima

    2014-01-01

    Background: Neonatal respiratory distress syndrome (RDS) in premature infants who survived and its complications are a common problem. Due to high morbidity and mechanical ventilation (MV) nowadays researchers in interested minimizing MV. To determine, in very low birth weight (BW) preterm neonates with RDS, if initial treatment with nasal intermittent mandatory ventilation (early NIMV) compared with early nasal continuous positive airway pressure (early NCPAP) obtains more favorable outcomes in terms of the duration of treatment, and the need for endotracheal tube ventilation. Methods: In this single-center randomized control trial study, infants (BW ≤ 1500 g and/or gestational age ≤ 34 weeks) with respiratory distress were considered eligible. Forty-four infants were randomly assigned to receive early-NIMV and 54 comparable infants to early-NCPAP. Surfactants were given, when FIO2 requirement was of >30%. Primary outcomes were failure of noninvasive respiratory support, that is, the need for MV in the first 48 h of life and for the duration of noninvasive respiratory support in each group. Results: 98 infants were enrolled (44 in the NIMV and 54 in the NCPAP group). The Preventive power of MV of NIMV usage (95.5%) was not lower than the NCPAP (98.1%) strength (hazard ratio: 0.21 (95% confidence interval: 0.02-2.66); P: 0.23). The duration of noninvasive respiratory support in the NIMV group was significantly shorter than NCPAP (the median (range) was 24 (18.00-48.00) h versus 48.00 (22.00-120.00) h in NIMV versus NCPAP groups; P < 0.001). Similarly, the duration of dependency on oxygen was less, for NIMV (the median (range) was 96.00 (41.00-504.00) h versus144.00 (70.00-1130.00) h in NIMV versus NCPAP groups; P: 0.009). Interestingly, time to full enteral feeds and length of hospital stay were more favorable in the NIMV versus the NCPAP group. Conclusions: Initial treatment of RDS with NIMV was safe, and well tolerated. Furthermore, NIMV had excellent

  12. Comparison of conventional mechanical ventilation and synchronous independent lung ventilation (SILV) in the treatment of unilateral lung injury.

    PubMed

    Hurst, J M; DeHaven, C B; Branson, R D

    1985-08-01

    Eight patients presenting with severe unilateral pulmonary injury responded poorly to conventional mechanical ventilation. Synchronous independent lung ventilation (SILV) was employed to provide support of ventilation and oxygenation without creating the ventilation/perfusion (V/Q) mismatch observed during conventional ventilation. All patients demonstrated improved oxygenation (mean increase, 80 torr) during SILV with the FIO2 unchanged from previous therapy. Invasive hemodynamic monitoring in five of eight patients showed no difference in the commonly measured cardiopulmonary parameters with the two forms of mechanical ventilation. Peak inspiratory pressure (PIP), continuous positive airway pressure (CPAP), and pressure change secondary to tidal volume delivery to the uninvolved lung were significantly less during SILV. SILV is an effective method of improving oxygenation in patients with severe unilateral pulmonary injury. PMID:3894680

  13. Weaning from mechanical ventilation: why are we still looking for alternative methods?

    PubMed

    Frutos-Vivar, F; Esteban, A

    2013-12-01

    Most patients who require mechanical ventilation for longer than 24 hours, and who improve the condition leading to the indication of ventilatory support, can be weaned after passing a first spontaneous breathing test. The challenge is to improve the weaning of patients who fail that first test. We have methods that can be referred to as traditional, such as the T-tube, pressure support or synchronized intermittent mandatory ventilation (SIMV). In recent years, however, new applications of usual techniques as noninvasive ventilation, new ventilation methods such as automatic tube compensation (ATC), mandatory minute ventilation (MMV), adaptive support ventilation or automatic weaning systems based on pressure support have been described. Their possible role in weaning from mechanical ventilation among patients with difficult or prolonged weaning remains to be established. PMID:23084120

  14. A model-based simulator for testing rule-based decision support systems for mechanical ventilation of ARDS patients.

    PubMed Central

    Sailors, R. M.; East, T. D.

    1994-01-01

    A model-based simulator was developed for testing rule-based decision support systems that manages ventilator therapy of patients with the Adult Respiratory Distress Syndrome (ARDS). The simulator is based on a multi-compartment model of the human body and mathematical models of the gas exchange abnormalities associated with ARDS. Initial testing of this system indicates that model-based simulators are a viable tool for testing rule-based expert systems used in health-care. PMID:7949849

  15. Real-Time Assessment of Autonomic Nerve Activity During Adaptive Servo-Ventilation Support or Waon Therapy.

    PubMed

    Imamura, Teruhiko; Kinugawa, Koichiro; Nitta, Daisuke; Komuro, Issei

    2016-07-27

    Adaptive servo-ventilation support and Waon therapy are recently developed non-pharmacological and noninvasive therapies for patients with heart failure refractory to guideline-directed medical therapy. These therapies decrease both preload and afterload, increase cardiac output, and appear to ameliorate autonomic nerve activity. However, the time course of autonomic nerve activity during these therapies remains unclear. We performed heart rate variability analysis using the MemCalc power spectral density method (MemCalc system; Suwa Trust Co, Tokyo) to assess autonomic nerve activity during adaptive servo-ventilation support and Waon therapy in two different cases and determined the time course of autonomic nerve activity during these therapies. During both therapies, we found a drastic increase in parasympathetic nerve activity and continuous suppression of sympathetic nerve activity. Heart rate variability analysis using the MemCalc method may be promising for the assessment of the efficacy of various treatments, including adaptive servo-ventilation support and Waon therapy, from the viewpoint of autonomic nerve activity. PMID:27385607

  16. Ventilation Model

    SciTech Connect

    V. Chipman

    2002-10-05

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. The purposes of Revision 01 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to initialize post

  17. Social Support, Assimilation and Biological Effective Blood Pressure Levels.

    ERIC Educational Resources Information Center

    Walsh, Anthony; Walsh, Patricia Ann

    1987-01-01

    The twin processes of migration and assimilation are highly stressful. This stress can be manifested in elevated blood pressure. According to this study, immigrants receiving high levels of social support had significantly lower blood pressure levels than those receiving less social support. (VM)

  18. Nasal ventilation.

    PubMed Central

    Simonds, A. K.

    1998-01-01

    Nasal intermittent positive pressure ventilation is likely to have an increasing role in the management of acute ventilatory failure, weaning, and chronic ventilatory problems. Further improvements in ventilator and mask design will be seen. Appropriate application is likely to reduce both mortality and admissions to intensive care, while domiciliary use can improve life expectancy and/or quality of life in chronic ventilatory disorders. As with any new technique, enthusiasm should not outweigh clear outcome information, and possible new indications should always be subject to careful assessment. Images Figure 2 PMID:9799887

  19. Pressure vessel sliding support unit and system using the sliding support unit

    SciTech Connect

    Breach, Michael R.; Keck, David J.; Deaver, Gerald A.

    2013-01-15

    Provided is a sliding support and a system using the sliding support unit. The sliding support unit may include a fulcrum capture configured to attach to a support flange, a fulcrum support configured to attach to the fulcrum capture, and a baseplate block configured to support the fulcrum support. The system using the sliding support unit may include a pressure vessel, a pedestal bracket, and a plurality of sliding support units.

  20. Combined Effects of Ventilation Mode and Positive End-Expiratory Pressure on Mechanics, Gas Exchange and the Epithelium in Mice with Acute Lung Injury

    PubMed Central

    Thammanomai, Apiradee; Hamakawa, Hiroshi; Bartolák-Suki, Erzsébet; Suki, Béla

    2013-01-01

    The accepted protocol to ventilate patients with acute lung injury is to use low tidal volume (VT) in combination with recruitment maneuvers or positive end-expiratory pressure (PEEP). However, an important aspect of mechanical ventilation has not been considered: the combined effects of PEEP and ventilation modes on the integrity of the epithelium. Additionally, it is implicitly assumed that the best PEEP-VT combination also protects the epithelium. We aimed to investigate the effects of ventilation mode and PEEP on respiratory mechanics, peak airway pressures and gas exchange as well as on lung surfactant and epithelial cell integrity in mice with acute lung injury. HCl-injured mice were ventilated at PEEPs of 3 and 6 cmH2O with conventional ventilation (CV), CV with intermittent large breaths (CVLB) to promote recruitment, and a new mode, variable ventilation, optimized for mice (VVN). Mechanics and gas exchange were measured during ventilation and surfactant protein (SP)-B, proSP-B and E-cadherin levels were determined from lavage and lung homogenate. PEEP had a significant effect on mechanics, gas exchange and the epithelium. The higher PEEP reduced lung collapse and improved mechanics and gas exchange but it also down regulated surfactant release and production and increased epithelial cell injury. While CVLB was better than CV, VVN outperformed CVLB in recruitment, reduced epithelial injury and, via a dynamic mechanotransduction, it also triggered increased release and production of surfactant. For long-term outcome, selection of optimal PEEP and ventilation mode may be based on balancing lung physiology with epithelial injury. PMID:23326543

  1. Combined effects of ventilation mode and positive end-expiratory pressure on mechanics, gas exchange and the epithelium in mice with acute lung injury.

    PubMed

    Thammanomai, Apiradee; Hamakawa, Hiroshi; Bartolák-Suki, Erzsébet; Suki, Béla

    2013-01-01

    The accepted protocol to ventilate patients with acute lung injury is to use low tidal volume (V(T)) in combination with recruitment maneuvers or positive end-expiratory pressure (PEEP). However, an important aspect of mechanical ventilation has not been considered: the combined effects of PEEP and ventilation modes on the integrity of the epithelium. Additionally, it is implicitly assumed that the best PEEP-V(T) combination also protects the epithelium. We aimed to investigate the effects of ventilation mode and PEEP on respiratory mechanics, peak airway pressures and gas exchange as well as on lung surfactant and epithelial cell integrity in mice with acute lung injury. HCl-injured mice were ventilated at PEEPs of 3 and 6 cmH(2)O with conventional ventilation (CV), CV with intermittent large breaths (CV(LB)) to promote recruitment, and a new mode, variable ventilation, optimized for mice (VV(N)). Mechanics and gas exchange were measured during ventilation and surfactant protein (SP)-B, proSP-B and E-cadherin levels were determined from lavage and lung homogenate. PEEP had a significant effect on mechanics, gas exchange and the epithelium. The higher PEEP reduced lung collapse and improved mechanics and gas exchange but it also down regulated surfactant release and production and increased epithelial cell injury. While CV(LB) was better than CV, VV(N) outperformed CV(LB) in recruitment, reduced epithelial injury and, via a dynamic mechanotransduction, it also triggered increased release and production of surfactant. For long-term outcome, selection of optimal PEEP and ventilation mode may be based on balancing lung physiology with epithelial injury. PMID:23326543

  2. Pulse pressure variation does not reflect stroke volume variation in mechanically ventilated rats with lipopolysaccharide-induced pneumonia.

    PubMed

    Cherpanath, Thomas G V; Smeding, Lonneke; Lagrand, Wim K; Hirsch, Alexander; Schultz, Marcus J; Groeneveld, Johan A B

    2014-01-01

    1. The present study examined the relationship between centrally measured stroke volume variation (SVV) and peripherally derived pulse pressure variation (PPV) in the setting of increased total arterial compliance (CA rt ). 2. Ten male Wistar rats were anaesthetized, paralysed and mechanically ventilated before being randomized to receive intrapulmonary lipopolysaccharide (LPS) or no LPS. Pulse pressure (PP) was derived from the left carotid artery, whereas stroke volume (SV) was measured directly in the left ventricle. Values of SVV and PPV were calculated over three breaths. Balloon inflation of a catheter positioned in the inferior vena cava was used, for a maximum of 30 s, to decrease preload while the SVV and PPV measurements were repeated. Values of CA rt were calculated as SV/PP. 3. Intrapulmonary LPS increased CA rt and SV. Values of SVV and PPV increased in both LPS-treated and untreated rats during balloon inflation. There was a correlation between SVV and PPV in untreated rats before (r = 0.55; P = 0.005) and during (r = 0.69; P < 0.001) occlusion of the vena cava. There was no such correlation in LPS-treated rats either before (r = -0.08; P = 0.70) or during (r = 0.36; P = 0.08) vena cava occlusion. 4. In conclusion, under normovolaemic and hypovolaemic conditions, PPV does not reflect SVV during an increase in CA rt following LPS-induced pneumonia in mechanically ventilated rats. Our data caution against their interchangeability in human sepsis. PMID:24372424

  3. A bench study of intensive-care-unit ventilators: new versus old and turbine-based versus compressed gas-based ventilators

    PubMed Central

    Thille, Arnaud W.; Lyazidi, Aissam; Richard, Jean-Christophe M.; Galia, Fabrice; Brochard, Laurent

    2009-01-01

    Objective To compare 13 commercially available, new-generation, intensive-care-unit (ICU) ventilators regarding trigger function, pressurization capacity during pressure-support ventilation (PSV), accuracy of pressure measurements and expiratory resistance. Design and Setting Bench study at a research laboratory in a university hospital. Material Four turbine-based ventilators and nine conventional servo-valve compressed-gas ventilators were tested using a two-compartment lung model. Results Three levels of effort were simulated. Each ventilator was evaluated at four PSV levels (5, 10, 15, and 20 cm H2O), with and without positive end-expiratory pressure (5 cm H2O, Trigger function was assessed as the time from effort onset to detectable pressurization. Pressurization capacity was evaluated using the airway pressure-time product computed as the net area under the pressure-time curve over the first 0.3 s after inspiratory effort onset. Expiratory resistance was evaluated by measuring trapped volume in controlled ventilation. Significant differences were found across the ventilators, with a range of triggering-delay from 42 ms to 88 ms for all conditions averaged (P<.001). Under difficult conditions, the triggering delay was longer than 100 ms and the pressurization was poor with five ventilators at PSV5 and three at PSV10, suggesting an inability to unload patient’s effort. On average, turbine-based ventilators performed better than conventional ventilators, which showed no improvement compared to a 2000 bench comparison. Conclusion Technical performances of trigger function, pressurization capacity and expiratory resistance vary considerably across new-generation ICU ventilators. ICU ventilators seem to have reached a technical ceiling in recent years, and some ventilators still perform inadequately. PMID:19352622

  4. The static pressure-volume relationship of the respiratory system determined with a computer-controlled ventilator.

    PubMed

    Svantesson, C; Drefeldt, B; Jonson, B

    1997-07-01

    The pressure-volume relationship of the respiratory system offers a guideline for setting of ventilators. The occlusion method for determination of the static elastic pressure-volume (Pel(st)/V) relationship is used as a reference and the aim of the study was to improve it with respect to time consumption and precision of recording and analysis. The inspiratory Pel(st)/V curve was determined with a computer-controlled ventilator using its pressure and flow sensors. During an automated procedure, an operator-defined volume history preceded each of a number of study breaths. These were interrupted at different volumes evenly distributed over a predefined volume interval. Total positive end-expiratory pressure (PEEP) was measured and could be separated into its components, external PEEP and auto-PEEP. The volume relationship between the curve and the current tidal volume was defined. An analytical method for definition of a linear segment of the Pel(st)/V curve and determination of its compliance is presented. In eight healthy human anaesthetized subjects duplicate Pel(st)/V curves were studied with respect to compliance and the position along the volume axis of the linear segment. The difference in compliance between measurements was 1.6 +/- 1.3 ml cmH2O(-1) or 1.2 +/- 0.9%. The position of the curve differed between measurements by 15 +/- 10 ml or by 1.1 +/- 0.9%. In a patient with acute lung injury the feasibility of applying a numerical method for a more detailed description of the Pel(st)/V curve was illustrated. PMID:19361153

  5. Ventilation and ventilators.

    PubMed

    Hayes, B

    1982-01-01

    The history of ventilation is reviewed briefly and recent developments in techniques of ventilation are discussed. Operating features of ventilators have changed in the past few years, partly as the result of clinical progress; yet, technology appears to have outstripped the clinician's ability to harness it most effectively. Clinical discipline and training of medical staff in the use of ventilators could be improved. The future is promising if clinician and designer can work together closely. Ergonomics of ventilators and their controls and the provision of alarms need special attention. Microprocessors are likely to feature prominently in the next generation of designs. PMID:6754938

  6. Noninvasive ventilation in large postoperative flail chest.

    PubMed

    Piastra, Marco; De Luca, Daniele; Zorzi, Giulia; Ruggiero, Antonio; Antonelli, Massimo; Conti, Giorgio; Pietrini, Domenico

    2008-12-01

    An 11-year-old male developed a severe respiratory failure due to a iatrogenic flail chest following a surgery for removing a large chest wall area. A rare Ewing sarcoma was histologically diagnosed and intensive chemotherapy was administered. Postoperatively, because of the failure in ventilation weaning, the patient was electively extubated and noninvasive positive pressure ventilation through face-mask was provided. Respiratory support avoided asynchronous paradoxical movements and achieved pneumatic stabilization. Clinical and respiratory improvement allowed a successful weaning from ventilator. PMID:18798557

  7. Bilateral diaphragmatic paralysis--a rare cause of acute respiratory failure managed with nasal mask bilevel positive airway pressure (BiPAP) ventilation.

    PubMed

    Lin, M C; Liaw, M Y; Huang, C C; Chuang, M L; Tsai, Y H

    1997-08-01

    A 68 yr old woman presented with acute respiratory failure. She was suspected of having a phrenic-diaphragmatic impairment, without evidence of an intrinsic lung disease or generalized neuromuscular disorder, after 3 weeks of prolonged mechanical ventilation. A series of studies, including fluoroscopy, phrenic nerve stimulation test and diaphragmatic electromyography, was performed before the diagnosis of bilateral diaphragmatic paralysis (BDP) was confirmed. The patient was successfully weaned from the conventional mechanical ventilator, and was placed on nasal mask bi-level positive airway pressure (BiPAP) ventilation. A high degree of clinical suspicion of bilateral diaphragmatic paralysis should always be raised in patients suffering respiratory failure without definite predisposing factors. Weaning with noninvasive nasal mask ventilation should be tried first instead of direct tracheostomy. PMID:9272940

  8. Monitoring of intratidal lung mechanics: a Graphical User Interface for a model-based decision support system for PEEP-titration in mechanical ventilation.

    PubMed

    Buehler, S; Lozano-Zahonero, S; Schumann, S; Guttmann, J

    2014-12-01

    In mechanical ventilation, a careful setting of the ventilation parameters in accordance with the current individual state of the lung is crucial to minimize ventilator induced lung injury. Positive end-expiratory pressure (PEEP) has to be set to prevent collapse of the alveoli, however at the same time overdistension should be avoided. Classic approaches of analyzing static respiratory system mechanics fail in particular if lung injury already prevails. A new approach of analyzing dynamic respiratory system mechanics to set PEEP uses the intratidal, volume-dependent compliance which is believed to stay relatively constant during one breath only if neither atelectasis nor overdistension occurs. To test the success of this dynamic approach systematically at bedside or in an animal study, automation of the computing steps is necessary. A decision support system for optimizing PEEP in form of a Graphical User Interface (GUI) was targeted. Respiratory system mechanics were analyzed using the gliding SLICE method. The resulting shapes of the intratidal compliance-volume curve were classified into one of six categories, each associated with a PEEP-suggestion. The GUI should include a graphical representation of the results as well as a quality check to judge the reliability of the suggestion. The implementation of a user-friendly GUI was successfully realized. The agreement between modelled and measured pressure data [expressed as root-mean-square (RMS)] tested during the implementation phase with real respiratory data from two patient studies was below 0.2 mbar for data taken in volume controlled mode and below 0.4 mbar for data taken in pressure controlled mode except for two cases with RMS < 0.6 mbar. Visual inspections showed, that good and medium quality data could be reliably identified. The new GUI allows visualization of intratidal compliance-volume curves on a breath-by-breath basis. The automatic categorisation of curve shape into one of six shape

  9. More Support for Aggressive Blood Pressure Treatment for Elderly

    MedlinePlus

    ... gov/news/fullstory_158851.html More Support for Aggressive Blood Pressure Treatment for Elderly Latest findings from ... SPRINT trial tested that approach against a more aggressive one, aiming to get patients of all ages ...

  10. Ventilator-patient dyssynchrony induced by change in ventilation mode.

    PubMed

    Lydon, A M; Doyle, M; Donnelly, M B

    2001-06-01

    Patient-ventilator interactions may be coordinated (synchronous) or uncoordinated (dyssynchronous). Ventilator-patient dyssynchrony increases the work of breathing by imposing a respiratory muscle workload. Respiratory centre output responds to feedback from respiratory muscle loading. Mismatching of respiratory centre output and mechanical assistance results in dyssynchrony. We describe a case of severe patient-ventilator dyssynchrony and hypothesize that dyssynchrony was induced by a change in mode of ventilation from pressure-cycled to volume-cycled ventilation, due to both ventilator settings and by the patient's own respiratory centre adaptation to mechanical ventilation. The causes, management and clinical implications of dyssynchrony are discussed. PMID:11439799

  11. New modes of assisted mechanical ventilation.

    PubMed

    Suarez-Sipmann, F

    2014-05-01

    Recent major advances in mechanical ventilation have resulted in new exciting modes of assisted ventilation. Compared to traditional ventilation modes such as assisted-controlled ventilation or pressure support ventilation, these new modes offer a number of physiological advantages derived from the improved patient control over the ventilator. By implementing advanced closed-loop control systems and using information on lung mechanics, respiratory muscle function and respiratory drive, these modes are specifically designed to improve patient-ventilator synchrony and reduce the work of breathing. Depending on their specific operational characteristics, these modes can assist spontaneous breathing efforts synchronically in time and magnitude, adapt to changing patient demands, implement automated weaning protocols, and introduce a more physiological variability in the breathing pattern. Clinicians have now the possibility to individualize and optimize ventilatory assistance during the complex transition from fully controlled to spontaneous assisted ventilation. The growing evidence of the physiological and clinical benefits of these new modes is favoring their progressive introduction into clinical practice. Future clinical trials should improve our understanding of these modes and help determine whether the claimed benefits result in better outcomes. PMID:24507472

  12. ICU nurses' preparation of families for death of patients following withdrawal of ventilator support.

    PubMed

    Kirchhoff, Karin T; Conradt, Kay Lynn; Anumandla, Prashanth Reddy

    2003-05-01

    Intensive care unit nurses were asked how they prepared families for the death of their patient following withdrawal of mechanical ventilation. Forty-three descriptors were identified, of which 67.5% (n = 29) were "physical sensations and symptoms." Less frequently mentioned features of Self-Regulation Theory were temporal characteristics, environmental features, and causes of these signs. Eight descriptors mentioned by more than 50% of nurses were skin color changes (74%), skin temperature changes (74%), varying levels of consciousness (74%), effort with breathing (71%), variable timeframe to death (68%), breathing pattern (65%), sound during breathing (61%), and loss of bowel control/incontinence (52%). PMID:12764719

  13. Support structure for a prestressed cylindrical pressure vessel

    SciTech Connect

    Schoening, J.; Schwiers, H.-G.

    1984-10-02

    A support structure for a nuclear power station having a prestressed cylindrical vessel comprising an annular ring of supports on a support wall and foundation wherein the prestressed cylindrical vessel rests on the ring of supports is disclosed. The supports, through their defined distances from each other, provide a constant cooling flow of the supports and a constant temperature over the entire operating period of the power station. This results in supports that are maintenance-free. The supports are constructed of plastic washers with steel inserts and are of sufficient height such that in the case of earthquakes, maximum vibrations of the reinforced concrete pressure vessel may be absorbed within an accurately set terminal boundary of the annular support wall.

  14. A case series of skin necrosis following use of non invasive ventilation pressure masks.

    PubMed

    Ahmad, Z; Venus, M; Kisku, W; Rayatt, S S

    2013-02-01

    Two cases of nasal skin necrosis secondary to pressure from the use of continuous positive airway pressure (CPAP) face masks are presented. Both developed skin necrosis as a result of wearing these masks over the nasal bridge. These cases highlight the need for clinical vigilance in application of CPAP masks, the need for monitoring the skin of the nose during CPAP use and the possible need for modifications in design to help prevent this serious complication. PMID:22432901

  15. Invasive and non-invasive ventilation for prematurely born infants - current practice in neonatal ventilation.

    PubMed

    Greenough, Anne; Lingam, Ingran

    2016-02-01

    Non-invasive techniques, include nasal continuous positive airways pressure (nCPAP), nasal intermittent positive pressure ventilation (NIPPV) and heated, humidified, high flow cannula (HHFNC). Randomised controlled trials (RCTs) of nCPAP versus ventilation have given mixed results, but one demonstrated fewer respiratory problems during infancy. Meta-analysis demonstrated NIPPV rather than nCPAP provided better support post extubation. After extubation or initial support HHFNC has similar efficacy to CPAP. Invasive techniques include those that synchronise inflations with the patient's respiratory efforts. Assist control/ synchronised intermittent mandatory ventilation compared to non triggered modes only reduce the duration of ventilation. Further data are required to determine the efficacy of proportional assist ventilation and neurally adjusted ventilatory assist. Other techniques aim to minimise volutrauma. RCTs of volume targeted ventilation demonstrated reductions in BPD and respiratory medication usage at follow-up. Prophylactic high frequency oscillatory ventilation does not reduce BPD, but is associated with superior lung function at school age. PMID:26698269

  16. Heat Exchanger/Humidifier Trade Study and Conceptual Design for the Constellation Space Suit Portable Life Support System Ventilation Subsystem

    NASA Technical Reports Server (NTRS)

    Paul, Heather L.; Sompayrac, Robert; Conger, Bruce; Chamberlain, Mateo

    2009-01-01

    As development of the Constellation Space Suit Element progresses, designing the most effective and efficient life support systems is critical. The baseline schematic analysis for the Portable Life Support System (PLSS) indicates that the ventilation loop will need some method of heat exchange and humidification prior to entering the helmet. A trade study was initiated to identify the challenges associated with conditioning the spacesuit breathing gas stream for temperature and water vapor control, to survey technological literature and resources on heat exchanger and humidifiers to provide solutions to the problems of conditioning the spacesuit breathing gas stream, and to propose potential candidate technologies to perform the heat exchanger and humidifier functions. This paper summarizes the results of this trade study and also describes the conceptual designs that NASA developed to address these issues.

  17. Heat Exchanger/Humidifier Trade Study and Conceptual Design for the Constellation Space Suit Portable Life Support System Ventilation Subsystem

    NASA Technical Reports Server (NTRS)

    Paul, Heather L.; Conger, Bruce; Sompyrac, Robert; Chamberlain, Mateo

    2008-01-01

    As development of the Constellation Space Suit Element progresses, designing the most effective and efficient life support systems is critical. The baseline schematic analysis for the Portable Life Support System (PLSS) indicates that the ventilation loop will need some method of heat exchange and humidification prior to entering the helmet. A trade study was initiated to identify the challenges associated with conditioning the spacesuit breathing gas stream for temperature and water vapor control, to survey technological literature and resources on heat exchanger and humidifiers to provide solutions to the problems of conditioning the spacesuit breathing gas stream, and to propose potential candidate technologies to perform the heat exchanger and humidifier functions. This paper summarizes the results of this trade study and also describes the conceptual designs that NASA developed to address these issues.

  18. Protective garment ventilation system

    NASA Technical Reports Server (NTRS)

    Lang, R. (Inventor)

    1970-01-01

    A method and apparatus for ventilating a protective garment, space suit system, and/or pressure suits to maintain a comfortable and nontoxic atmosphere within is described. The direction of flow of a ventilating and purging gas in portions of the garment may be reversed in order to compensate for changes in environment and activity of the wearer. The entire flow of the ventilating gas can also be directed first to the helmet associated with the garment.

  19. Neurally adjusted ventilator assist in very low birth weight infants: Current status

    PubMed Central

    Narchi, Hassib; Chedid, Fares

    2015-01-01

    Continuous improvements in perinatal care have resulted in increased survival of premature infants. Their immature lungs are prone to injury with mechanical ventilation and this may develop into chronic lung disease (CLD) or bronchopulmonary dysplasia. Strategies to minimize the risk of lung injury have been developed and include improved antenatal management (education, regionalization, steroids, and antibiotics), exogenous surfactant administration and reduction of barotrauma by using exclusive or early noninvasive ventilatory support. The most frequently used mode of assisted ventilation is pressure support ventilation that may lead to patient-ventilator asynchrony that is associated with poor outcome. Ventilator-induced diaphragmatic dysfunction or disuse atrophy of diaphragm fibers may also occur. This has led to the development of new ventilation modes including neurally adjusted ventilatory assist (NAVA). This ventilation mode is controlled by electrodes embedded within a nasogastric catheter which detect the electrical diaphragmatic activity (Edi) and transmit it to trigger the ventilator in synchrony with the patient’s own respiratory efforts. This permits the patient to control peak inspiratory pressure, mean airway pressure and tidal volume. Back up pressure control (PC) is provided when there is no Edi signal and no pneumatic trigger. Compared with standard conventional ventilation, NAVA improves blood gas regulation with lower peak inspiratory pressure and oxygen requirements in preterm infants. NAVA is safe mode of ventilation. The majority of studies have shown no significant adverse events in neonates ventilated with NAVA nor a difference in the rate of intraventricular hemorrhage, pneumothorax, or necrotizing enterocolitis when compared to conventional ventilation. Future large size randomized controlled trials should be established to compare NAVA with volume targeted and pressure controlled ventilation in newborns with mature respiratory drive

  20. Neurally adjusted ventilator assist in very low birth weight infants: Current status.

    PubMed

    Narchi, Hassib; Chedid, Fares

    2015-06-26

    Continuous improvements in perinatal care have resulted in increased survival of premature infants. Their immature lungs are prone to injury with mechanical ventilation and this may develop into chronic lung disease (CLD) or bronchopulmonary dysplasia. Strategies to minimize the risk of lung injury have been developed and include improved antenatal management (education, regionalization, steroids, and antibiotics), exogenous surfactant administration and reduction of barotrauma by using exclusive or early noninvasive ventilatory support. The most frequently used mode of assisted ventilation is pressure support ventilation that may lead to patient-ventilator asynchrony that is associated with poor outcome. Ventilator-induced diaphragmatic dysfunction or disuse atrophy of diaphragm fibers may also occur. This has led to the development of new ventilation modes including neurally adjusted ventilatory assist (NAVA). This ventilation mode is controlled by electrodes embedded within a nasogastric catheter which detect the electrical diaphragmatic activity (Edi) and transmit it to trigger the ventilator in synchrony with the patient's own respiratory efforts. This permits the patient to control peak inspiratory pressure, mean airway pressure and tidal volume. Back up pressure control (PC) is provided when there is no Edi signal and no pneumatic trigger. Compared with standard conventional ventilation, NAVA improves blood gas regulation with lower peak inspiratory pressure and oxygen requirements in preterm infants. NAVA is safe mode of ventilation. The majority of studies have shown no significant adverse events in neonates ventilated with NAVA nor a difference in the rate of intraventricular hemorrhage, pneumothorax, or necrotizing enterocolitis when compared to conventional ventilation. Future large size randomized controlled trials should be established to compare NAVA with volume targeted and pressure controlled ventilation in newborns with mature respiratory drive

  1. Regenerative Blower for EVA Suit Ventilation Fan

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Paul, Heather L.

    2010-01-01

    Portable life support systems in future space suits will include a ventilation subsystem driven by a dedicated fan. This ventilation fan must meet challenging requirements for pressure rise, flow rate, efficiency, size, safety, and reliability. This paper describes research and development that showed the feasibility of a regenerative blower that is uniquely suited to meet these requirements. We proved feasibility through component tests, blower tests, and design analysis. Based on the requirements for the Constellation Space Suit Element (CSSE) Portable Life Support System (PLSS) ventilation fan, we designed the critical elements of the blower. We measured the effects of key design parameters on blower performance using separate effects tests, and used the results of these tests to design a regenerative blower that will meet the ventilation fan requirements. We assembled a proof-of-concept blower and measured its performance at sub-atmospheric pressures that simulate a PLSS ventilation loop environment. Head/flow performance and maximum efficiency point data were used to specify the design and operating conditions for the ventilation fan. We identified materials for the blower that will enhance safety for operation in a lunar environment, and produced a solid model that illustrates the final design. The proof-of-concept blower produced the flow rate and pressure rise needed for the CSSE ventilation subsystem while running at 5400 rpm, consuming only 9 W of electric power using a non-optimized, commercial motor and controller and inefficient bearings. Scaling the test results to a complete design shows that a lightweight, compact, reliable, and low power regenerative blower can meet the performance requirements for future space suit life support systems.

  2. Using Pressure and Support to Create a Qualified Workforce

    ERIC Educational Resources Information Center

    Ryan, Sharon; Ackerman, Debra J.

    2005-01-01

    In order for any new initiative to be implemented, it is generally assumed that policy actors need both motivation to comply with a new initiative and adequate assistance to implement the required change successfully. The study reported here examined the impact of a system of pressure and supports created to encourage preschool teachers working in…

  3. Clinical challenges in mechanical ventilation.

    PubMed

    Goligher, Ewan C; Ferguson, Niall D; Brochard, Laurent J

    2016-04-30

    Mechanical ventilation supports gas exchange and alleviates the work of breathing when the respiratory muscles are overwhelmed by an acute pulmonary or systemic insult. Although mechanical ventilation is not generally considered a treatment for acute respiratory failure per se, ventilator management warrants close attention because inappropriate ventilation can result in injury to the lungs or respiratory muscles and worsen morbidity and mortality. Key clinical challenges include averting intubation in patients with respiratory failure with non-invasive techniques for respiratory support; delivering lung-protective ventilation to prevent ventilator-induced lung injury; maintaining adequate gas exchange in severely hypoxaemic patients; avoiding the development of ventilator-induced diaphragm dysfunction; and diagnosing and treating the many pathophysiological mechanisms that impair liberation from mechanical ventilation. Personalisation of mechanical ventilation based on individual physiological characteristics and responses to therapy can further improve outcomes. PMID:27203509

  4. Continuous Positive Airway Pressure versus Mechanical Ventilation on the First Day of Life in Very Low-Birth-Weight Infants.

    PubMed

    Flannery, Dustin D; O'Donnell, Elizabeth; Kornhauser, Mike; Dysart, Kevin; Greenspan, Jay; Aghai, Zubair H

    2016-08-01

    Objective The objective of this study was to determine differences in the incidence of bronchopulmonary dysplasia (BPD) or death in very low-birth-weight (VLBW) infants managed successfully on continuous positive airway pressure (CPAP) versus mechanical ventilation on the first day of life (DOL). Study Design This is a retrospective analysis of the Alere neonatal database for infants born between January 2009 and December 2014, weighing ≤ 1,500 g. Baseline demographics, clinical characteristics, and outcomes were compared between the two groups. Multivariable regression analysis was performed to control the variables that differ in bivariate analysis. Results In this study, 4,629 infants (birth weight 1,034 ± 290 g, gestational age 28.1 ± 2.5 weeks) met the inclusion criteria. The successful use of early CPAP was associated with a significant reduction in BPD or death (p < 0.001), as well as days to room air, decreased oxygen use at discharge, lower risk for severe intraventricular hemorrhage, and patent ductus arteriosus requiring surgical ligation (p < 0.001 for all outcomes). Conclusion Successful use of early CPAP on the first DOL in VLBW infants is associated with a reduced risk of BPD or death. PMID:27057767

  5. Performance of ICU ventilators during noninvasive ventilation with large leaks in a total face mask: a bench study* **

    PubMed Central

    Nakamura, Maria Aparecida Miyuki; Costa, Eduardo Leite Vieira; Carvalho, Carlos Roberto Ribeiro; Tucci, Mauro Roberto

    2014-01-01

    Objective: Discomfort and noncompliance with noninvasive ventilation (NIV) interfaces are obstacles to NIV success. Total face masks (TFMs) are considered to be a very comfortable NIV interface. However, due to their large internal volume and consequent increased CO2 rebreathing, their orifices allow proximal leaks to enhance CO2 elimination. The ventilators used in the ICU might not adequately compensate for such leakage. In this study, we attempted to determine whether ICU ventilators in NIV mode are suitable for use with a leaky TFM. Methods: This was a bench study carried out in a university research laboratory. Eight ICU ventilators equipped with NIV mode and one NIV ventilator were connected to a TFM with major leaks. All were tested at two positive end-expiratory pressure (PEEP) levels and three pressure support levels. The variables analyzed were ventilation trigger, cycling off, total leak, and pressurization. Results: Of the eight ICU ventilators tested, four did not work (autotriggering or inappropriate turning off due to misdetection of disconnection); three worked with some problems (low PEEP or high cycling delay); and one worked properly. Conclusions: The majority of the ICU ventilators tested were not suitable for NIV with a leaky TFM. PMID:25029653

  6. Pinching, electrocution, ravens' beaks, and positive pressure ventilation: a brief history of neonatal resuscitation

    PubMed Central

    O'Donnell, C P F; Gibson, A T; Davis, P G

    2006-01-01

    Since ancient times many different methods have been used to revive newborns. Although subject to the vagaries of fashion for 2000 years, artificial respiration has been accepted as the mainstay of neonatal resuscitation for about the last 40. Formal teaching programmes have evolved over the last 20 years. The last 10 years have seen international collaboration, which has resulted in careful evaluation of the available evidence and publication of recommendations for clinical practice. There is, however, little evidence to support current recommendations, which are largely based on expert opinion. The challenge for neonatologists today is to gather robust evidence to support or refute these recommendations, thereby refining this common and important intervention. PMID:16923936

  7. Noninvasive and invasive positive pressure ventilation for acute respiratory failure in critically ill patients: a comparative cohort study

    PubMed Central

    Meeder, Annelijn M.; Tjan, Dave H. T.

    2016-01-01

    Background Noninvasive positive pressure ventilation (NPPV) for acute respiratory failure in the intensive care unit (ICU) is associated with a marked reduction in intubation rate, complications, hospital length of stay and mortality. Multiple studies have indicated that patients failing NPPV have worse outcomes compared with patients with successful NPPV treatment; however limited data is available on risks associated with NPPV failure resulting in (delayed) intubation and outcomes compared with initial intubation. The purpose of this study is to assess rates and predictors of NPPV failure and to compare hospital outcomes of patients with NPPV failure with those patients primarily intubated without a prior NPPV trial. Methods A retrospective observational study using data from patients with acute respiratory failure admitted to the ICU in the period 2013–2014. All patients treated with NPPV were evaluated. A sample of patients who were primarily intubated was randomly selected to serve as controls for the group of patients who failed NPPV. Results NPPV failure was recorded in 30.8% of noninvasively ventilated patients and was associated with longer ICU stay [OR, 1.16, 95% confidence interval (95% CI): 1.04–1.30] and lower survival rates (OR, 0.10, 95% CI: 0.02–0.59) compared with NPPV success. Multivariate analysis showed presence of severe sepsis at study entry, higher Simplified Acute Physiology II Score (SAPS-II) score, lower ratio of arterial oxygen tension to fraction of inspired oxygen (PF-ratio) and lower plasma glucose were predictors for NPPV failure. After controlling for potential confounders, patients with NPPV failure did not show any difference in hospital outcomes compared with patients who were primarily intubated. Conclusions Patients with acute respiratory failure and NPPV failure have worse outcomes compared with NPPV success patients, however not worse than initially intubated patients. An initial trial of NPPV therefore may be suitable

  8. Validity of transcutaneous oxygen/carbon dioxide pressure measurement in the monitoring of mechanical ventilation in stable chronic respiratory failure.

    PubMed

    Rosner, V; Hannhart, B; Chabot, F; Polu, J M

    1999-05-01

    The accuracy and precision of transcutaneous pressure measurements of oxygen (Ptc,O2) and carbon dioxide (Ptc,CO2) in the monitoring of nocturnal assisted ventilation in adult patients were evaluated. Transcutaneous measurements obtained with two analysers, Radiometer TINATCM3 (R) and Kontron MicroGas-7650 (K), were compared with arterial blood gases analysed in blood samples withdrawn simultaneously in 10 patients. Sensors were heated to 43 degrees C. Measurements of transcutaneous blood gases and arterial blood gases were collected six times at 1-h intervals. The data obtained with both instruments were similar and did not significantly change over the 5 h test period. Measurement of Ptc,O2 underestimated arterial oxygen tension (Pa,O2) and this underestimation increased with the level of Pa,O2 (p<0.01). Measurements of Ptc,CO2 overestimated arterial carbon dioxide tension (Pa,CO2) and this overestimation increased with the level of Pa,CO2 (p<0.05). These errors suggested an instrumental bias. Mathematical correction of this bias neutralized the error in accuracy and improved the precision (SD of the differences transcutaneous blood gases - arterial blood gases). An additional correction, suppressing the between-subject scattering, improved the actual precision: precision was reduced from 1.9 to 0.8 kPa (14.4 to 5.7 mmHg) (R) and from 1.7 to 0.5 kPa (13.1 to 3.7 mmHg) (K) for oxygen, and from 1.0 kPa (7.8 mmHg) (R) and 0.7 kPa (5.6 mmHg) (K) to 0.4 kPa (3.2 mmHg) for carbon dioxide (R and K). In conclusion, with these two successive corrections, transcutaneous oxygen and carbon dioxide provide a reliable estimation of blood gases to monitor nocturnal ventilation in adults with chronic respiratory failure. PMID:10414402

  9. Protective lung ventilation in operating room: a systematic review.

    PubMed

    Futier, E; Constantin, J M; Jaber, S

    2014-06-01

    Postoperative pulmonary and extrapulmonary complications adversely affect clinical outcomes and healthcare utilization, so that prevention has become a measure of the quality of perioperative care. Mechanical ventilation is an essential support therapy to maintain adequate gas exchange during general anesthesia for surgery. Mechanical ventilation using high tidal volume (VT) (between 10 and 15 mL/kg) has been historically encouraged to prevent hypoxemia and atelectasis formation in anesthetized patients undergoing abdominal and thoracic surgery. However, there is accumulating evidence from both experimental and clinical studies that mechanical ventilation, especially the use of high VT and plateau pressure, may potentially aggravate or even initiate lung injury. Ventilator-associated lung injury can result from cyclic alveolar overdistension of non-dependent lung tissue, and repetitive opening and closing of dependent lung tissue resulting in ultrastructural damage at the junction of closed and open alveoli. Lung-protective ventilation, which refers to the use of lower VT and limited plateau pressure to minimize overdistension, and positive end-expiratory pressure to prevent alveolar collapse at end-expiration, was shown to improve outcome in critically ill patients with acute respiratory distress syndrome (ARDS). It has been recently suggested that this approach might also be beneficial in a broader population, especially in critically ill patients without ARDS at the onset of mechanical ventilation. There is, however, little evidence regarding a potential beneficial effect of lung protective ventilation during surgery, especially in patients with healthy lungs. Although surgical patients are frequently exposed to much shorter periods of mechanical ventilation, this is an important gap in knowledge given the number of patients receiving mechanical ventilation in the operating room. This review developed the benefits of lung protective ventilation during surgery

  10. Turbulence production and turbulent pressure support in the intergalactic medium

    NASA Astrophysics Data System (ADS)

    Iapichino, L.; Schmidt, W.; Niemeyer, J. C.; Merklein, J.

    2011-07-01

    The injection and evolution of turbulence in the intergalactic medium is studied by means of mesh-based hydrodynamical simulations, including a subgrid-scale (SGS) model for small-scale unresolved turbulence. The simulations show that the production of turbulence has a different redshift dependence in the intracluster medium (ICM) and the warm-hot intergalactic medium (WHIM). We show that the turbulence in the ICM is produced chiefly by merger-induced shear flows, whereas the production in the WHIM is dominated by shock interactions. Secondly, the effect of dynamical pressure support on the gravitational contraction has been studied. This turbulent support is stronger in the WHIM gas at baryon overdensities 1 ≲δ≲ 100 and less relevant for the ICM. Although the relative mass fraction of the gas with large vorticity is considerable (52 per cent in the ICM), we find that for only about 10 per cent in mass this is dynamically relevant, namely not associated with an equally large thermal pressure support. According to this result, a significant non-thermal pressure support counteracting the gravitational contraction is a localized characteristic in the cosmic flow, rather than a widespread feature.

  11. Respiratory outcome in late childhood after neonatal continuous negative pressure ventilation

    PubMed Central

    Telford, K; Waters, L; Vyas, H; Manktelow, B N; Draper, E S; Marlow, N

    2007-01-01

    Background The outcome in late childhood for children entered into a randomised trial of continuous negative extrathoracic pressure (CNEP) versus standard respiratory management for the treatment of neonatal respiratory distress was studied. In the original trial, there were advantages in the duration of oxygen and the prevalence of chronic lung disease for those assigned to receive CNEP. Aim To determine whether the above differences had persisted into childhood. Methods Outpatient evaluation of children by a paediatrician using Spirometry (Vitalograph Spirometer 2120, Ennis, Ireland) and MicroRint (Micro Medical, Rochester, Kent, UK) techniques independently of the original trial. Parents completed questionnaires about their child's respiratory history and social–demographic information. Results 133 (65%) survivors were evaluated at 9.6–14.9 years of age. The group examined were representative of the original cohort and no significant baseline differences were observed between children evaluated who had been allocated to CNEP or standard treatments. We compared Rint (before and after bronchodilator) and forced expiratory flow, volume and vital capacity between the two study groups; none were significant. Children in the standard group had received paediatric intensive care more often (p = 0.19) and were more likely to be receiving inhaled drugs for asthma (p = 0.19; all not significant). Conclusions No important differences were found at follow‐up in late childhood in respiratory outcomes for children treated with neonatal CNEP or standard treatment. Caution should be exercised, as the original trial was not powered to show these differences, but there seems to be no long‐term detriment in respiratory outcomes for children treated with CNEP in the neonatal period. PMID:16905573

  12. A new model of chronic intermittent hypoxia in humans: effect on ventilation, sleep, and blood pressure

    PubMed Central

    Tamisier, R.; Gilmartin, G. S.; Launois, S. H.; Pépin, J. L.; Nespoulet, H.; Thomas, R.; Lévy, P.; Weiss, J. W.

    2009-01-01

    Obstructive sleep apnea is characterized by repetitive nocturnal upper airway obstructions that are associated with sleep disruption and cyclic intermittent hypoxia (CIH) The cyclic oscillations in O2 saturation are thought to contribute to cardiovascular and other morbidity, but animal and patient studies of the pathogenic link between CIH and these diseases have been complicated by species differences and by the effects of confounding factors such as obesity, hypertension, and impaired glucose metabolism. To minimize these limitations, we set up a model of nocturnal CIH in healthy humans. We delivered O2 for 15 s every 2 min during sleep while subjects breathed 13% O2 in a hypoxic tent to create 30 cycles/h of cyclic desaturation-reoxygenation [saturation of peripheral O2 (SpO2) range: 95–85%]. We exposed subjects overnight for 8–9 h/day for 2 wk (10 subjects) and 4 wk (8 subjects). CIH exposure induced respiratory disturbances (central apnea hypopnea index: 3.0 ± 1.9 to 31.1 ± 9.6 events/h of sleep at 2 wk). Exposure to CIH for 14 days induced an increase in slopes of hypoxic and hypercapnic ventilatory responses (1.5 ± 0.6 to 3.1 ± 1.2 l·min−1·% drop in SpO2 and 2.2 ± 1.0 to 3.3 ± 0.9 l·min−1·mmHg CO2−1, respectively), consistent with hypoxic acclimatization. Waking normoxic arterial pressure increased significantly at 2 wk at systolic (114 ± 2 to 122 ± 2 mmHg) and for diastolic at 4 wk (71 ± 1.3 to 74 ± 1.7 mmHg). We propose this model as a new technique to study the cardiovascular and metabolic consequences of CIH in human volunteers. PMID:19228987

  13. Effects of Intermittent Positive Pressure Ventilation on Cardiopulmonary Function in Horses Anesthetized with Total Intravenous Anesthesia Using Combination of Medetomidine, Lidocaine, Butorphanol and Propofol (MLBP-TIVA)

    PubMed Central

    ISHIZUKA, Tomohito; TAMURA, Jun; NAGARO, Tsukasa; SUDO, Kanako; ITAMI, Takaharu; UMAR, Mohammed Ahamed; MIYOSHI, Kenjirou; SANO, Tadashi; YAMASHITA, Kazuto

    2014-01-01

    Effects of intermittent positive pressure ventilation (IPPV) on cardiopulmonary function were evaluated in horses anesthetized with total intravenous anesthesia using constant rate infusions of medetomidine (3.5 µg/kg/hr), lidocaine (3 mg/kg/hr), butorphanol (24 µg/kg/hr) and propofol (0.1 mg/kg/min) (MLBP-TIVA). Five horses were anesthetized twice using MLBP-TIVA with or without IPPV at 4-week interval (crossover study). In each occasion, the horses breathed 100% oxygen with spontaneous ventilation (SB-group, n=5) or with IPPV (CV-group, n=5), and changes in cardiopulmonary parameters were observed for 120 min. In the SB-group, cardiovascular parameters were maintained within acceptable ranges (heart rate: 33–35 beats/min, cardiac output: 27–30 l/min, mean arterial blood pressure [MABP]: 114–123 mmHg, mean pulmonary arterial pressure [MPAP]: 28–29 mmHg and mean right atrial pressure [MRAP]: 19–21 mmHg), but severe hypercapnea and insufficient oxygenation were observed (arterial CO2 pressure [PaCO2]: 84–103 mmHg and arterial O2 pressure [PaO2]: 155–172 mmHg). In the CV-group, normocapnea (PaCO2: 42–50 mmHg) and good oxygenation (PaO2: 395–419 mmHg) were achieved by the IPPV without apparent cardiovascular depression (heart rate: 29–31 beats/min, cardiac output: 17–21 l /min, MABP: 111–123 mmHg, MPAP: 27–30 mmHg and MRAP: 15–16 mmHg). MLBP-TIVA preserved cardiovascular function even in horses artificially ventilated. PMID:25649938

  14. Effects of intermittent positive pressure ventilation on cardiopulmonary function in horses anesthetized with total intravenous anesthesia using combination of medetomidine, lidocaine, butorphanol and propofol (MLBP-TIVA).

    PubMed

    Ishizuka, Tomohito; Tamura, Jun; Nagaro, Tsukasa; Sudo, Kanako; Itami, Takaharu; Umar, Mohammed Ahamed; Miyoshi, Kenjirou; Sano, Tadashi; Yamashita, Kazuto

    2014-12-01

    Effects of intermittent positive pressure ventilation (IPPV) on cardiopulmonary function were evaluated in horses anesthetized with total intravenous anesthesia using constant rate infusions of medetomidine (3.5 µg/kg/hr), lidocaine (3 mg/kg/hr), butorphanol (24 µg/kg/hr) and propofol (0.1 mg/kg/min) (MLBP-TIVA). Five horses were anesthetized twice using MLBP-TIVA with or without IPPV at 4-week interval (crossover study). In each occasion, the horses breathed 100% oxygen with spontaneous ventilation (SB-group, n=5) or with IPPV (CV-group, n=5), and changes in cardiopulmonary parameters were observed for 120 min. In the SB-group, cardiovascular parameters were maintained within acceptable ranges (heart rate: 33-35 beats/min, cardiac output: 27-30 l/min, mean arterial blood pressure [MABP]: 114-123 mmHg, mean pulmonary arterial pressure [MPAP]: 28-29 mmHg and mean right atrial pressure [MRAP]: 19-21 mmHg), but severe hypercapnea and insufficient oxygenation were observed (arterial CO(2) pressure [PaCO(2)]: 84-103 mmHg and arterial O(2) pressure [PaO(2)]: 155-172 mmHg). In the CV-group, normocapnea (PaCO(2): 42-50 mmHg) and good oxygenation (PaO(2): 395-419 mmHg) were achieved by the IPPV without apparent cardiovascular depression (heart rate: 29-31 beats/min, cardiac output: 17-21 l /min, MABP: 111-123 mmHg, MPAP: 27-30 mmHg and MRAP: 15-16 mmHg). MLBP-TIVA preserved cardiovascular function even in horses artificially ventilated. PMID:25649938

  15. Experimental Investigation of Ventilation of a Surface Piercing Hydrofoil

    NASA Astrophysics Data System (ADS)

    Harwood, Casey; Miguel Montero, Francisco; Young, Yin Lu; Ceccio, Steven

    2013-11-01

    Bodies that pierce a liquid free-surface are prone to entrainment of atmospheric and/or vaporous gases. This process, called ventilation, can occur suddenly and violently, drastically altering hydrodynamic response. Experiments have been conducted at the free-surface towing-tank in the University of Michigan Marine Hydrodynamics Laboratory to investigate fully attached, partially ventilated, and fully ventilated flows around a canonical surface-piercing hydrofoil. The objectives of the work are: (i) to gain a broad and improved understanding of the physics of ventilation, (ii) to classify the physical mechanisms by which ventilation inception and washout may occur and quantify the conditions required for each mechanism and (iii) to quantify the effects of ventilation on global hydrodynamic responses, including the six force and moment components. Experimental data and high-speed video will be used to illustrate the impact of ventilation on hydrodynamic loads, pressures, and flow structures. The completion of this study is expected to contribute significantly toward a comprehensive understanding of ventilation physics, and toward an improved ability to design safe and controllable ventilated lifting surfaces for use in propulsion, energy harvesting, and turbomachinery. Supported by: The Office of Naval Research (ONR) (Grant No. N00014-09-1-1204); the National Research Foundation of Korea (NRF) (GCRC-SOP Grant No. 2012-0004783); the National Science Foundation Graduate Student Research Fellowship (Grant No. DGE 1256260).

  16. Automated stroke volume and pulse pressure variations predict fluid responsiveness in mechanically ventilated patients with obstructive jaundice

    PubMed Central

    Zhao, Feng; Wang, Peng; Pei, Shujun; Mi, Weidong; Fu, Qiang

    2015-01-01

    Background and objectives: Stroke volume variation (SVV) and the pulse pressure variation (PPV) have been found to be effective in prediction fluid responsiveness especially in high risk operations. The objective of this study is to validate the ability of SVV obtained by FloTrac/Vigileo system and PPV obtained by IntelliVue MP System to predict fluid responsiveness in patients with obstructive jaundice during mechanical ventilation. Methods: Twentyfive patients with obstructive jaundice (mean serum total bilirubin 175.0 ± 120.8 μmol/L), who accepted volume expansion and were hemodynamically stable after induction of anesthesia, were included in the study. SVV and PPV were recorded simultaneously before and after an intravascular volume expansion. Patients with a stroke volume index (SVI) increase of more than 10% after volume expansion were considered as responders. Results: The agreement (mean bias ± SD) between SVV and PPV was -0.2% ± 1.56%. Before volume expansion, SVV and PPV were significantly higher in responders compared to non-responders (P<0.001, P<0.001). Significant correlation was observed between the baseline value of SVV and PPV and the percent change in SVI after fluid expansion (r=0.654, P<0.001; r=0.592, P=0.002). Area under the receiver operating characteristic curves of SVV (0.955) and PPV (0.875) were comparable (P=0.09). The optimal threshold values in predicting fluid responsiveness were 10% for SVV and 8% for PPV. Conclusion: In conclusion, SVV obtained by FloTrac/Vigileo system and PPV obtained by IntelliVue MP System was able to predict fluid responsiveness in patients with obstructive jaundice. PMID:26884998

  17. Open circuit mouthpiece ventilation: Concise clinical review.

    PubMed

    Garuti, G; Nicolini, A; Grecchi, B; Lusuardi, M; Winck, J C; Bach, J R

    2014-01-01

    In 2013 new "mouthpiece ventilation" modes are being introduced to commercially available portable ventilators. Despite this, there is little knowledge of how to use noninvasive intermittent positive pressure ventilation (NIV) as opposed to bi-level positive airway pressure (PAP) and both have almost exclusively been reported to have been used via nasal or oro-nasal interfaces rather than via a simple mouthpiece. Non-invasive ventilation is often reported as failing because of airway secretion encumbrance, because of hypercapnia due to inadequate bi-level PAP settings, or poor interface tolerance. The latter can be caused by factors such as excessive pressure on the face from poor fit, excessive oral air leak, anxiety, claustrophobia, and patient-ventilator dys-synchrony. Thus, the interface plays a crucial role in tolerance and effectiveness. Interfaces that cover the nose and/or nose and mouth (oro-nasal) are the most commonly used but are more likely to cause skin breakdown and claustrophobia. Most associated drawbacks can be avoided by using mouthpiece NIV. Open-circuit mouthpiece NIV is being used by large populations in some centers for daytime ventilatory support and complements nocturnal NIV via "mask" interfaces for nocturnal ventilatory support. Mouthpiece NIV is also being used for sleep with the mouthpiece fixed in place by a lip-covering flange. Small 15 and 22mm angled mouthpieces and straw-type mouthpieces are the most commonly used. NIV via mouthpiece is being used as an effective alternative to ventilatory support via tracheostomy tube (TMV) and is associated with a reduced risk of pneumonias and other respiratory complications. Its use facilitates "air-stacking" to improve cough, speech, and pulmonary compliance, all of which better maintain quality of life for patients with neuromuscular diseases (NMDs) than the invasive alternatives. Considering these benefits and the new availability of mouthpiece ventilator modes, wider knowledge of this

  18. Effect of Pressure Controlled Waveforms on Flow Transport and Gas mixing in a Patient Specific Lung Model during Invasive High Frequency Oscillatory Ventilation

    NASA Astrophysics Data System (ADS)

    Alzahrany, Mohammed; Banerjee, Arindam

    2012-11-01

    A computational fluid dynamic study is carried out to investigate gas transport in patient specific human lung models (based on CT scans) during high frequency oscillatory ventilation (HFOV). Different pressure-controlled waveforms and various ventilator frequencies are studied to understand the effect of flow transport and gas mixing during these processes. Three different pressure waveforms are created by solving the equation of motion subjected to constant lung wall compliance and flow resistance. Sinusoidal, exponential and constant waveforms shapes are considered with three different frequencies 6, 10 and 15 Hz and constant tidal volume 50 ml. The velocities are calculated from the obtained flow rate and imposed as inlet flow conditions to represent the mechanical ventilation waveforms. An endotracheal tube ETT is joined to the model to account for the effect of the invasive management device with the peak Reynolds number (Re) for all the cases ranging from 6960 to 24694. All simulations are performed using high order LES turbulent model. The gas transport near the flow reversal will be discussed at different cycle phases for all the cases and a comparison of the secondary flow structures between different cases will be presented.

  19. Ventilation Model Report

    SciTech Connect

    V. Chipman; J. Case

    2002-12-20

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. Revision 01 ICN 01 included the results of the unqualified software code MULTIFLUX to assess the influence of moisture on the ventilation efficiency. The purposes of Revision 02 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of

  20. Mechanical ventilation in children.

    PubMed

    Kendirli, Tanil; Kavaz, Asli; Yalaki, Zahide; Oztürk Hişmi, Burcu; Derelli, Emel; Ince, Erdal

    2006-01-01

    Mechanical ventilation can be lifesaving, but > 50% of complications in conditions that require intensive care are related to ventilatory support, particularly if it is prolonged. We retrospectively evaluated the medical records of patients who had mechanical ventilation in the Pediatric Intensive Care Unit (PICU) during a follow-up period between January 2002-May 2005. Medical records of 407 patients were reviewed. Ninety-one patients (22.3%) were treated with mechanical ventilation. Ages of all patients were between 1-180 (median: 8) months. The mechanical ventilation time was 18.8 +/- 14.1 days. Indication of mechanical ventilation could be divided into four groups as respiratory failure (64.8%), cardiovascular failure (19.7%), central nervous system disease (9.8%) and safety airway (5.4%). Tracheostomy was performed in four patients. The complication ratio of mechanically ventilated children was 42.8%, and diversity of complications was as follows: 26.3% atelectasia, 17.5% ventilator-associated pneumonia, 13.1% pneumothorax, 5.4% bleeding, 4.3% tracheal edema, and 2.1% chronic lung disease. The mortality rate of mechanically ventilated patients was 58.3%, but the overall mortality rate in the PICU was 12.2%. In conclusion, there are few published epidemiological data on the follow-up results and mortality in infants and children who are mechanically ventilated. PMID:17290566

  1. Noninvasive ventilation in trauma.

    PubMed

    Karcz, Marcin K; Papadakos, Peter J

    2015-02-01

    Trauma patients are a diverse population with heterogeneous needs for ventilatory support. This requirement depends mainly on the severity of their ventilatory dysfunction, degree of deterioration in gaseous exchange, any associated injuries, and the individual feasibility of potentially using a noninvasive ventilation approach. Noninvasive ventilation may reduce the need to intubate patients with trauma-related hypoxemia. It is well-known that these patients are at increased risk to develop hypoxemic respiratory failure which may or may not be associated with hypercapnia. Hypoxemia in these patients is due to ventilation perfusion mismatching and right to left shunt because of lung contusion, atelectasis, an inability to clear secretions as well as pneumothorax and/or hemothorax, all of which are common in trauma patients. Noninvasive ventilation has been tried in these patients in order to avoid the complications related to endotracheal intubation, mainly ventilator-associated pneumonia. The potential usefulness of noninvasive ventilation in the ventilatory management of trauma patients, though reported in various studies, has not been sufficiently investigated on a large scale. According to the British Thoracic Society guidelines, the indications and efficacy of noninvasive ventilation treatment in respiratory distress induced by trauma have thus far been inconsistent and merely received a low grade recommendation. In this review paper, we analyse and compare the results of various studies in which noninvasive ventilation was applied and discuss the role and efficacy of this ventilator modality in trauma. PMID:25685722

  2. Efficacy of Bilevel-auto Treatment in Patients with Obstructive Sleep Apnea Not Responsive to or Intolerant of Continuous Positive Airway Pressure Ventilation

    PubMed Central

    Carlucci, Annalisa; Ceriana, Piero; Mancini, Marco; Cirio, Serena; Pierucci, Paola; D'Artavilla Lupo, Nadia; Gadaleta, Felice; Morrone, Elisa; Fanfulla, Francesco

    2015-01-01

    Background: Ventilation with continuous positive airway pressure (CPAP) is the gold standard therapy for obstructive sleep apnea (OSA). However, it was recently suggested that a novel mode of ventilation, Bilevel-auto, could be equally effective in treating patients unable to tolerate CPAP. The aim of this study was to investigate the ability of Bilevel-auto to treat OSA patients whose nocturnal ventilatory disturbances are not completely corrected by CPAP. Methods: We enrolled 66 consecutive OSA patients, not responsive to (group A) or intolerant of (group B) CPAP treatment, after a full night of manual CPAP titration in a laboratory. Full polysomnography data and daytime sleepiness score were compared for each group in the three different conditions: basal, during CPAP, and during Bilevel-auto. Results: The apnea-hypopnea index decreased significantly during CPAP in both groups; however, in the group A, there was a further significant improvement during Bilevel-auto. The same trend was observed for oxygenation indices, while the distribution and the efficiency of sleep did not differ following the switch from CPAP to Bilevel-auto. Conclusions: This study confirmed the role of Bilevel-auto as an effective therapeutic alternative to CPAP in patients intolerant of this latter mode of ventilation. Moreover, extending the use of Bilevel-auto to those OSA patients not responsive to CPAP, we showed a significantly better correction of nocturnal respiratory disturbances. Citation: Carlucci A, Ceriana P, Mancini M, Cirio S, Pierucci P, D'Artavilla Lupo N, Gadaleta F, Morrone E, Fanfulla F. Efficacy of Bilevel-auto treatment in patients with obstructive sleep apnea not responsive to or intolerant of continuous positive airway pressure ventilation. J Clin Sleep Med 2015;11(9):981–985. PMID:25902825

  3. Effects of Noninvasive Positive-Pressure Ventilation with Different Interfaces in Patients with Hypoxemia after Surgery for Stanford Type A Aortic Dissection

    PubMed Central

    Yang, Yi; Sun, Lizhong; Liu, Nan; Hou, Xiaotong; Wang, Hong; Jia, Ming

    2015-01-01

    Background Hypoxemia is a severe perioperative complication that can substantially increase intensive care unit and hospital stay and mortality. The aim of this study was to determine the effects of non-invasive positive-pressure ventilation (NIPPV) in patients with hypoxemia after surgery for Stanford type A aortic dissection, and to compare the effects of helmet and mask NIPPV. Material/Methods We recruited 40 patients who developed hypoxemia within 24 h after extubation after surgery for Stanford type A aortic dissection in the Beijing Anzhen Hospital. The patients were randomly divided into the helmet and mask NIPPV groups. The primary endpoints were blood oxygenation levels at 1 and 6 h after initiation and at the end of the treatment. The secondary endpoint was patient outcome, including mortality; incidence of pulmonary atelectasis, pneumonia, re-intubation, and sepsis; and length of ICU and hospital stays. Results NIPPV improved oxygenation in both groups. Compared with pretreatment levels, the oxygenation index (PaO2/FiO2), PaO2, PaCO2, and respiratory rate (RR) improved in the initial (0–1 h), maintenance (1–6 h), and end stages of the treatment (P<0.05). Compared with mask ventilation, helmet ventilation better improved pH, PaO2, SpO2, PaO2/FiO2, and decreased PaCO2 in the 3 stages (P<0.05). The incidence of major complications, including flatulence, intolerance, and facial pressure sores, was significantly lower with helmet ventilation. Conclusions NIPPV effectively improved oxygenation and reduced PaCO2 in patients who developed hypoxemia soon after extubation following surgery for Stanford type A aortic dissection. Compared with mask NIPPV, helmet NIPPV more rapidly increased PaO2 and reduced PaCO2, increased patient tolerance and comfort, and reduced complications. PMID:26250834

  4. Selecting ventilator settings according to variables derived from the quasi-static pressure/volume relationship in patients with acute lung injury.

    PubMed

    Putensen, C; Baum, M; Hörmann, C

    1993-09-01

    Knowledge of the pressure/volume (P/V) relationship of the lung may allow selection of tidal volume and positive end-expiratory pressure (PEEP) to optimize gas exchange without adversely affecting lung function or hemodynamics. Ten patients with acute lung injury were stabilized on controlled mechanical ventilation, based on conventional practice, using criteria from arterial blood gas data. The P/V relationship was determined under quasi-static conditions (end-expiratory and end-inspiratory, no flow periods > 0.8 s) during mechanical ventilation with an automated procedure that changed PEEP in a stepwise fashion. Differences in expiratory tidal volumes before and after a change in PEEP equaled the change in functional residual capacity (delta FRC). PEEP was set above the lowest point of the steepest section of the P/V curve (inflection pressure) to prevent end-expiratory lung collapse. Inspiratory tidal volumes (VTI) were adjusted to avoid an end-inspiratory lung volume reaching the flat part of the P/V curve. Averaged delta FRC versus PEEP curves were shifted to the left and the slope increased 1, 6, and 12 h after changing ventilator settings compared to baseline (P < 0.01). Averaged baseline delta FRC versus PEEP curves showed a marked inflection pressure that decreased after adjusting ventilator settings (P < 0.01). PEEP was increased from 7.4 +/- 1.8 cm H2O (baseline) to 11.9 +/- 1.6 cm H2O (1 h) (P < 0.001) according to measured baseline inflection pressures. Simultaneously, VTI had to be reduced from 759 +/- 161 mL (baseline) to 664 +/- 101 mL (1 h) (P < 0.01) to avoid end-inspiratory overinflation. To maintain minute volume constant ventilator frequency was increased from 14 +/- 1.2 (baseline) to 16 +/- 1.2 breaths/min (1 h) (P < 0.01). Maximum quasi-static compliance of 38 +/- 7 mL/cm H2O (baseline) increased to 46 +/- 9 mL/cm H2O (1 h) (P < 0.01). Maintaining FIO2 constant, PaO2 increased from a baseline of 90 +/- 16 mm Hg to 122 +/- 24 mm Hg (1 h) (P

  5. Developments in longwall ventilation

    SciTech Connect

    Brune, J.F.; Aman, J.P.; Kotch, M.

    1999-07-01

    Rapid development in longwall mining technology has brought significant changes in panel layout and geometry. These changes require adaptations in the ventilation system to provide sufficient air quantities in longwall face and bleeder areas. At CONSOL, various longwall bleeder systems in the Pittsburgh No. 8 Seam have been studied with detailed ventilation surveys. Computer model network simulations were conducted from these surveys to study the effects of different bleeder configurations and ventilation adjustments. This paper examines the relationships between the longwall face air quantity and the convergence in the tailgate-to-bleeder entries, number of development entries, bleeder fan pressure and the tailgate ventilation scheme. It shows that, using conventional ventilation patterns, the face air quantity may be limited if the gob caves tightly. In such cases, modification of the ventilation pattern to an internal bleeder system, combined with appropriate tailgate ventilation and higher bleeder fan pressure may be required. Experience in CONSOL's operations has proven this method successful especially in mines that changed from four-entry to three-entry longwall development.

  6. Social Support and Nocturnal Blood Pressure Dipping: A Systematic Review

    PubMed Central

    2013-01-01

    BACKGROUND Attenuated nocturnal blood pressure (BP) dipping is a better predictor of cardiovascular disease (CVD) morbidity and mortality than resting BP measurements. Studies have reported associations between social support, variously defined, and BP dipping. METHODS A systematic review of the literature was conducted to investigate associations of functional and structural social support with nocturnal BP dipping assessed over a minimum of 24 hours. RESULTS A total of 297 articles were identified. Of these, 11 met criteria for inclusion; all studies were cross-sectional in design and included adult participants only (mean age = 19 to 72 years). Evidence was most consistent for an association between functional support and BP dipping, such that 5 of 7 studies reported statistically (or marginally) significant positive associations with BP dipping. Statistically significant functional support–BP dipping associations were moderate (standardized effect size (d) = 0.41) to large (d = 2.01) in magnitude. Studies examining structural support were fewer and relatively less consistent; however, preliminary evidence was observed for associations of marital status and social contact frequency with BP dipping. Statistically significant structural support findings were medium (d = 0.53) to large (d = 1.13) in magnitude. CONCLUSIONS Overall, findings suggest a link between higher levels of functional support and greater nocturnal BP dipping; preliminary evidence was also observed for the protective effects of marriage and social contact frequency. Nonetheless, the relatively small number of studies conducted to date and the heterogeneity of findings across meaningful subgroups suggest that additional research is needed to substantiate these conclusions. PMID:23382479

  7. Autotitrating versus standard noninvasive ventilation: a randomised crossover trial.

    PubMed

    Jaye, J; Chatwin, M; Dayer, M; Morrell, M J; Simonds, A K

    2009-03-01

    The aim of the present study was to compare the efficacy of automatic titration of noninvasive ventilation (NIV) with conventional NIV in stable neuromuscular and chest wall disorder patients established on long-term ventilatory support. In total, 20 neuromuscular and chest wall disease patients with nocturnal hypoventilation treated with long-term NIV completed a randomised crossover trial comparing two noninvasive pressure support ventilators: a standard bilevel ventilator (VPAP III) and a novel autotitrating bilevel ventilator (AutoVPAP). Baseline physiological measurements, overnight polysomnography and Holter monitoring were repeated at the end of each 1-month treatment period. Nocturnal oxygenation was comparable between the autotitrating device and standard ventilator, as were sleep efficiency, arousals and heart rate variability. However, there was a small significant increase in mean overnight transcutaneous carbon dioxide tension (median (interquartile range) 7.2 (6.7-7.7) versus 6.7 (6.1-7.0) kPa) and a decrease in percentage stage 1 sleep (mean+/-sd 16+/-9 versus 19+/-10%) on autotitrating NIV compared with conventional NIV. Autotitrating noninvasive ventilation using AutoVPAP produced comparable control of nocturnal oxygenation to standard nonivasive ventilation, without compromising sleep quality in stable neuromuscular and chest wall disease patients requiring long-term ventilatory support for nocturnal hypoventilation. PMID:19251798

  8. The comparison of manual and LabVIEW-based fuzzy control on mechanical ventilation.

    PubMed

    Guler, Hasan; Ata, Fikret

    2014-09-01

    The aim of this article is to develop a knowledge-based therapy for management of rats with respiratory distress. A mechanical ventilator was designed to achieve this aim. The designed ventilator is called an intelligent mechanical ventilator since fuzzy logic was used to control the pneumatic equipment according to the rat's status. LabVIEW software was used to control all equipments in the ventilator prototype and to monitor respiratory variables in the experiment. The designed ventilator can be controlled both manually and by fuzzy logic. Eight female Wistar-Albino rats were used to test the designed ventilator and to show the effectiveness of fuzzy control over manual control on pressure control ventilation mode. The anesthetized rats were first ventilated for 20 min manually. After that time, they were ventilated for 20 min by fuzzy logic. Student's t-test for p < 0.05 was applied to the measured minimum, maximum and mean peak inspiration pressures to analyze the obtained results. The results show that there is no statistical difference in the rat's lung parameters before and after the experiments. It can be said that the designed ventilator and developed knowledge-based therapy support artificial respiration of living things successfully. PMID:25205667

  9. Mechanical ventilation with positive end-expiratory pressure decreases the circulating concentrations of the N-terminus and C-terminus of the atrial natriuretic factor prohormone.

    PubMed

    Vesely, D L; Salmon, J S

    1990-01-01

    Mechanical ventilation with positive end-expiratory pressure (PEEP) decreases urine output and urinary sodium excretion. The influence of PEEP during controlled mechanical ventilation on the circulating concentrations of the N-terminus and C-terminus of the atrial natriuretic factor (ANF) prohormone which both contain natriuretic and diuretic peptides was investigated in 7 patients with acute respiratory failure. The 98 amino acid (aa) N-terminus, the midportion of the N-terminus consisting of aa 31-67 of the 126 aa ANF prohormone (i.e., pro ANF 31-67) and the C-terminus (aa 99-126; ANF) were found to be significantly (p less than 0.05; ANOVA) elevated compared to 54 healthy volunteers during acute respiratory failure prior to institution of PEEP. With institution of 10 cm of H2O of PEEP all 7 patients had a significant (p less than 0.05) decrease in the circulating concentrations of pro ANFs 1-98, 31-67 and ANF. These findings suggest that the increased thoracic pressure secondary to PEEP which reduces venous return and lowers atrial filling pressure results in a decreased release of the N-terminus and C-terminus of the ANF prohormone. This decrease in the N-terminus and C-terminus of the ANF prohormone appears to represent a physiologic mechanism for restoration of intravascular volume, secondary to decreased sodium excretion. PMID:2151585

  10. Neurally adjusted non-invasive ventilation in patients with chronic obstructive pulmonary disease: does patient-ventilator synchrony matter?

    PubMed

    Nava, Stefano; Pisani, Lara

    2014-01-01

    Patient-ventilator interaction represents an important clinical challenge during non-invasive ventilation (NIV). Doorduin and colleagues' study shows that non-invasive neurally adjusted ventilatory assist (NAVA) improves patient-ventilator interaction compared with pressure support ventilation in patients with chronic obstructive pulmonary disease. There is no doubt nowadays that NAVA is the most effective mode of improving the synchrony between patient and machine, but the key question for the clinicians is whether or not this will make a difference to the patient's outcome. The results of the study still do not clarify this issue because of the very low clinically important dyssynchrony, like wasted efforts, in the population studied. Air leaks play an important role in determining patient-ventilator interaction and therefore NIV success or failure. Apart from the use of a dedicated NIV ventilator or specific modes of ventilation like NAVA, the clinicians should be aware that the choice of interface, the humidification system and the appropriate sedation are key factors in improving patient-ventilator synchrony. PMID:25672776

  11. Regenerative Blower for EVA Suit Ventilation Fan

    NASA Technical Reports Server (NTRS)

    Paul, Heather; Izenson, Mike; Chen, Weibo

    2008-01-01

    Portable life support systems in future space suits will include a ventilation subsystem driven by a dedicated fan. This ventilation fan must meet challenging requirements for pressure rise, flow rate, efficiency, size, safety, and reliability. This paper describes research and development that showed the feasibility of a regenerative blower that is uniquely suited to meet these requirements. We proved feasibility through component tests, blower tests, and design analysis. Based on the requirements for the Constellation Space Suit ventilation fan, we designed the critical elements of the blower. We measured the effects of key design parameters on blower performance using separate effects tests, and used the results of these tests to design a regenerative blower that will meet the ventilation fan requirements. We assembled a proof-of-concept blower and measured its performance at low pressures that simulate a PLSS environment. We obtained head/flow performance curves over a range of operating speeds, identified the maximum efficiency point for the blower, and used these results to specify the design and operating conditions for the ventilation fan. We designed a compact motor that can drive the blower under all anticipated operating requirements and operate with high efficiency during normal operation. We identified materials for the blower that will enhance safety for operation in a lunar environment. We produced a solid model that illustrates the final design. The proof-of-concept blower produced the flow rate and pressure rise needed for the CSSS ventilation subsystem while running at 5400 rpm and consuming only 9 W of electric power and using a non-optimized, commercial motor and controller and inefficient bearings. Scaling the test results to a complete design shows that a lightweight, compact, reliable, and low power blower can meet the performance requirements for future PLSSs.

  12. Oscillations of radiation pressure supported tori near black holes

    NASA Astrophysics Data System (ADS)

    Mazur, Grzegorz P.; Zanotti, Olindo; Sądowski, Aleksander; Mishra, Bhupendra; Kluźniak, Wlodek

    2016-03-01

    We study the dynamics of radiation pressure supported tori around Schwarzschild black holes, focusing on their oscillatory response to an external perturbation. Using KORAL, a general relativistic radiation-hydrodynamics code capable of modelling all radiative regimes from the optically thick to the optically thin, we monitor a sample of models at different initial temperatures and opacities, evolving them in two spatial dimensions for ˜165 orbital periods. The dynamics of models with high opacity is very similar to that of purely hydrodynamics models, and it is characterized by regular oscillations which are visible also in the light curves. As the opacity is decreased, the tori quickly and violently migrate towards the gas-pressure dominated regime, collapsing towards the equatorial plane. When the spectra of the L2 norm of the mass density are considered, high-frequency inertial-acoustic modes of oscillations are detected (with the fundamental mode at a frequency 68 M_BH^{-1} Hz), in close analogy to the phenomenology of purely hydrodynamic models. An additional mode of oscillation, at a frequency 129 M_BH^{-1} Hz, is also found, which can be unambiguously attributed to the radiation. The spectra extracted from the light curves are typically noisier, indicating that in a real observation such modes may not be easily detected.

  13. Efficiency and outcome of non-invasive versus invasive positive pressure ventilation therapy in respiratory failure due to chronic obstructive pulmonary disease.

    PubMed Central

    Amri Maleh, Valiollah; Monadi, Mahmood; Heidari, Behzad; Maleh, Parviz Amri; Bijani, Ali

    2016-01-01

    Background: Application noninvasive ventilation in the patients with exacerbation of chronic obstructive pulmonary disease (COPD) reduced mortality. This case-control study was designed to compare efficiency and outcome of non-invasive (NIV) versus invasive positive pressure ventilation (IPPV) in respiratory failure due to COPD. Methods: The patients were assigned to NIV or IPPV intermittantly.The clinical parameters, including RR (respiratory rate), BP (blood pressure), HR (heart rate) and PH, PaCO2, PaO2 before and 1, 4 and 24 h after treatment were measured. Demographic information such as age, sex, severity of disease based on APACHE score, length of stay and outcome were recorded. Results: Fifty patients were enrolled in the NIV group and 50 patients in IPPV. The mean age was 70.5 in NIV and 63.9 in invasive ventilation group (p>0.05). In IPPV group, the average values of PH: PCO2: and PO2, were 7.22±0.11, 69.64 + 24.25: and 68.86±24.41 .In NIV, the respective values were 7.30±0.07, 83.94±18.95, and 60.60±19.88. In NIV group, after 1, 4 and 24 h treatment, the clinical and ventilation parameters were stable. The mean APACHE score in was IPPV, 26.46±5.45 and in NIV was 12.26±5.54 (p<0.05). The average length of hospital stay in IPPV was 15.90±10 and in NIV 8.12±6.49 days (p<0.05). The total mortality in the NIV was 4 (8%) and in IPPV, 27 patients (54%) (p<0.05). Conclusion: This study indicates that using NIPPV is a useful therapeutic mode of treatment for respiratory failure with acceptable success rate and lower mortality. The application of NIPPV reduces hospital stay, intubation and its consequent complications.

  14. [Collateral ventilation].

    PubMed

    Voshaar, Th H

    2008-06-01

    The phenomenon of collateral ventilation is defined as ventilation of alveolar structures through passages or channels that bypass the normal airways. Such bypassing structures can be interalveolar, bronchiole-alveolar, interbronchiole, and interlobar. Collateral ventilation structures seem to be prominent in human lungs with trapped air and emphysema. In healthy human lungs normally no relevant collateral ventilation can be detected. In emphysematic lungs the ventilation through collateral channels can probably improve gas exchange mechanisms. The phenomenon of collateral ventilation explains several clinical observations in human lungs such as the absence of atalectasis following complete bronchial obstruction, e. g. after foreign body aspiration or tumour. The various results after bronchoscopic implantation of one-way endobronchial valves as a new technique for treating emphysema can also be explained by collateral ventilation. Understanding collateral ventilation is of high importance for clinicians, those working in the field of physiology of emphysema in human lungs and may be central to planning new bronchoscopic techniques for treating emphysema. The paper offers an overview of history, physiology and the relevance for lung volume reduction methods. Moreover, a new imaging technique to demonstrate collateral ventilation in vivo is described. PMID:18535980

  15. Sustained inflation and incremental mean airway pressure trial during conventional and high-frequency oscillatory ventilation in a large porcine model of acute respiratory distress syndrome

    PubMed Central

    Muellenbach, Ralf M; Kredel, Markus; Zollhoefer, Bernd; Wunder, Christian; Roewer, Norbert; Brederlau, Joerg

    2006-01-01

    Background To compare the effect of a sustained inflation followed by an incremental mean airway pressure trial during conventional and high-frequency oscillatory ventilation on oxygenation and hemodynamics in a large porcine model of early acute respiratory distress syndrome. Methods Severe lung injury (Ali) was induced in 18 healthy pigs (55.3 ± 3.9 kg, mean ± SD) by repeated saline lung lavage until PaO2 decreased to less than 60 mmHg. After a stabilisation period of 60 minutes, the animals were randomly assigned to two groups: Group 1 (Pressure controlled ventilation; PCV): FIO2 = 1.0, PEEP = 5 cmH2O, VT = 6 ml/kg, respiratory rate = 30/min, I:E = 1:1; group 2 (High-frequency oscillatory ventilation; HFOV): FIO2 = 1.0, Bias flow = 30 l/min, Amplitude = 60 cmH2O, Frequency = 6 Hz, I:E = 1:1. A sustained inflation (SI; 50 cmH2O for 60s) followed by an incremental mean airway pressure (mPaw) trial (steps of 3 cmH2O every 15 minutes) were performed in both groups until PaO2 no longer increased. This was regarded as full lung inflation. The mPaw was decreased by 3 cmH2O and the animals reached the end of the study protocol. Gas exchange and hemodynamic data were collected at each step. Results The SI led to a significant improvement of the PaO2/FiO2-Index (HFOV: 200 ± 100 vs. PCV: 58 ± 15 and TAli: 57 ± 12; p < 0.001) and PaCO2-reduction (HFOV: 42 ± 5 vs. PCV: 62 ± 13 and TAli: 55 ± 9; p < 0.001) during HFOV compared to lung injury and PCV. Augmentation of mPaw improved gas exchange and pulmonary shunt fraction in both groups, but at a significant lower mPaw in the HFOV treated animals. Cardiac output was continuously deteriorating during the recruitment manoeuvre in both study groups (HFOV: TAli: 6.1 ± 1 vs. T75: 3.4 ± 0.4; PCV: TAli: 6.7 ± 2.4 vs. T75: 4 ± 0.5; p < 0.001). Conclusion A sustained inflation followed by an incremental mean airway pressure trial in HFOV improved oxygenation at a lower mPaw than during conventional lung protective

  16. Radiation-pressure-supported obscuring tori around active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Pier, Edward A.; Krolik, Julian H.

    1992-01-01

    Radiation pressure acting on dust grains can support the vertical thickness of the obscuring tori believed to exist in active galactic nuclei. Using the results of 2D radiation transfer calculations, we evaluate the radiation force acting on these tori. We find that on the inner edge of the torus the radiation force is about 350 l(E) times the gravitational force of the nucleus, where l(E) is the Eddington ratio. Beyond a few torus heights from the inner edge, the radiation force is negligible with respect to gravity. However, between these two extremes lies a region of considerable size where the ratio of radiation force to gravity is nearly constant and can be of order unity for l(E) about 0.1. If the distribution of material within the torus is sufficiently lumpy, there is a significant time-varying component to the radiation force. This drives the random motions of the constituent clouds, thickening the torus at lower values of l(E).

  17. Inter-Module Ventilation Changes to the International Space Station Vehicle to Support Integration of the International Docking Adapter and Commercial Crew Vehicles

    NASA Technical Reports Server (NTRS)

    Link, Dwight E., Jr.; Balistreri, Steven F., Jr.

    2015-01-01

    The International Space Station (ISS) Environmental Control and Life Support System (ECLSS) is continuing to evolve in the post-Space Shuttle era. The ISS vehicle configuration that is in operation was designed for docking of a Space Shuttle vehicle, and designs currently under development for commercial crew vehicles require different interfaces. The ECLSS Temperature and Humidity Control Subsystem (THC) Inter-Module Ventilation (IMV) must be modified in order to support two docking interfaces at the forward end of ISS, to provide the required air exchange. Development of a new higher-speed IMV fan and extensive ducting modifications are underway to support the new Commercial Crew Vehicle interfaces. This paper will review the new ECLSS IMV development requirements, component design and hardware status, subsystem analysis and testing performed to date, and implementation plan to support Commercial Crew Vehicle docking.

  18. Measurement of ventilation during cardiopulmonary resuscitation.

    PubMed

    Ornato, J P; Bryson, B L; Donovan, P J; Farquharson, R R; Jaeger, C

    1983-02-01

    Determining adequacy of mechanical ventilation is as important during CPR as in a more stable situation (such as, a patient on a ventilator in an ICU). Yet, such assessment during CPR usually only means listening for breath sounds, checking chest excursion, and blood gases. Exhaled tidal volume (VT) was measured on 45 intubated adult patients during resuscitation using a Wright's spirometer attached to a T-valve above the endotracheal tube. Ten patients had aspiration prior to intubation; 15 received advanced cardiac life support in the field, including esophageal airway insertion. CPR was performed in all cases with a mechanical compression device (Thumper). The pressure ventilator on this device was calibrated (peak inspiratory pressure, VT vs compliance) using a Dixie Test Lung, allowing indirect assessment of pulmonary compliance during CPR. Our findings suggest that lung compliance is markedly reduced within a short time after cardiac arrest. Fifty-five % of patients in this series could not be adequately oxygenated (PaO2 less than 50 torr) despite an FIO2 of 0.8 and adequate ventilation. Due to the reduced cardiac output during CPR causing venoarterial shunting, it is speculated that pulmonary edema is the most plausible explanation for this observation. PMID:6822084

  19. Ventilator-associated lung injury.

    PubMed

    Kuchnicka, Katarzyna; Maciejewski, Dariusz

    2013-01-01

    Mechanical ventilation of disease-affected lungs, as well as being an inadequate mode of ventilation for initially healthy lungs, can cause significant changes in their structure and function. In order to differentiate these processes, two terms are used: ventilator-associated lung injury (VALI) and ventilator-induced lung injury (VILI). In both cases, lung injury primarily results from differences in transpulmonary pressure - a consequence of an imbalance between lung stress and strain. This paper focuses on changes in lung structure and function due to this imbalance. Moreover, in this context, barotrauma, volutrauma and atelectrauma are interpreted, and the importance of signal transduction as a process inducing local and systemic inflammatory responses (biotrauma), is determined. None of the assessed methods of reducing VALI and VILI has been found to be entirely satisfactory, yet studies evaluating oscillatory ventilation, liquid ventilation, early ECMO, super-protective ventilation or noisy ventilation and administration of certain drugs are under way. Low tidal volume ventilation and adequately adjusted PEEP appear to be the best preventive measures of mechanical ventilation in any setting, including the operating theatre. Furthermore, this paper highlights the advances in VILI/VALI prevention resulting from better understanding of pathophysiological phenomena. PMID:24092514

  20. Effect of Intermittent Positive Pressure Ventilation on Depth of Anaesthesia during and after Isoflurane Anaesthesia in Sulphur-Crested Cockatoos (Cacatua galerita galerita)

    PubMed Central

    2014-01-01

    This study aimed to determine the effect of intermittent positive pressure ventilation (IPPV) on the depth of inhalation anaesthesia in parrots. Anaesthesia was induced with 3.0% isoflurane in six Sulphur-crested Cockatoos (Cacatua galerita galerita) and maintained using either 1.5% or 3.0% during spontaneous ventilation (SV) or IPPV at 6 (IPPV-6) or 12 (IPPV-12) breaths per minute. The time taken for the appearance of somatic reflexes and the return of SV after IPPV was recorded. During recovery, the body jerk, beak, eye, and shivering reflexes appeared after 126 ± 27 s, 133 ± 26 s, 165 ± 34 s, and 165 ± 44 s, respectively. All cockatoos developed apnoea after IPPV-12 and only some did after IPPV-6. Return of SV after IPPV-12 was delayed compared to IPPV-6. Recovery times after the SV runs were significantly different between 1.5% and 3.0% isoflurane anaesthesia. Similarly, after IPPV, the recovery times were significantly different between 1.5% and 3.0% isoflurane anaesthesia. Recovery times after 3.0% inhaled isoflurane were longer than those of 1.5% inhaled isoflurane. In conclusion, cockatoos recovering from isoflurane anaesthesia are likely to exhibit body jerk, beak, eye, and shivering reflexes in that order. IPPV increases the depth of anaesthesia in a rate and dose-related manner and prolongs recovery. PMID:24587938

  1. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip-Cleft Palate.

    PubMed

    George, Lovya; Jain, Sunil K

    2015-10-01

    Preterm infants (PIs) often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure. PMID:26495158

  2. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip–Cleft Palate

    PubMed Central

    George, Lovya; Jain, Sunil K.

    2015-01-01

    Preterm infants (PIs) often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure. PMID:26495158

  3. Trial of telemedicine for patients on home ventilator support: feasibility, confidence in clinical management and use in medical decision-making.

    PubMed

    Casavant, David W; McManus, Michael L; Parsons, Susan K; Zurakowski, David; Graham, Robert J

    2014-12-01

    We investigated whether telemedicine (videoconferencing) was feasible in patients with special care needs on home ventilation, whether it affected the confidence of families about the clinical management of their child, and whether it supported clinical decision-making. Videoconferencing software was provided free for 14 families who had a computer and webcam. Families completed questionnaires about clinical management before the addition of telemedicine and 2-3 months after they had used telemedicine. They also completed a questionnaire about their experience with videoconferencing. There were 27 telemedicine encounters during the 9-month study. Families reported higher confidence in clinical care with telemedicine compared to telephone. They also reported that the videoconferencing was high-quality, easy to use, and did not increase their telecommunication costs. The telemedicine encounters supported clinical decision-making, especially in patients with active clinical problems or when the patient was acutely ill. The telemedicine encounters prevented the need for 23 clinic visits, three emergency room visits, and probably one hospital admission. Although the study was small, videoconferencing appears useful in the management of medically fragile patients on home ventilator support, producing high levels of family confidence in clinical management and value to clinicians in their decision-making. PMID:25316042

  4. Respiratory controversies in the critical care setting. Should noninvasive positive-pressure ventilation be used in all forms of acute respiratory failure?

    PubMed

    Hess, Dean R; Fessler, Henry E

    2007-05-01

    Noninvasive positive-pressure ventilation (NPPV) has been a major advance in the management of acute respiratory failure. Over the past decade alone, NPPV has been the subject of over 1,500 scientific papers, including 14 meta-analyses. NPPV's utility in many clinical settings has been well established, with demonstration in randomized trials of lower intubation rate, mortality, hospital stay, and advantages in other important clinical outcomes. However, it is still used in a minority of patients with acute respiratory failure. While there probably are situations in which NPPV is commonly under-utilized, there are other situations in which it is unlikely to be of benefit or likely to inflict harm. This paper debates the data for and against the more widespread application of NPPV. It will assist the clinician to identify both good and poor candidates for NPPV and thereby devote respiratory care resources where they will be most effective, and optimize patient outcomes. PMID:17484789

  5. Effects of Alveolar Recruitment and Positive End-Expiratory Pressure on Oxygenation during One-Lung Ventilation in the Supine Position

    PubMed Central

    Choi, Yong Seon; Bae, Mi Kyung; Kim, Shin Hyung; Park, Ji-Eun; Kim, Soo Young

    2015-01-01

    Purpose Hypoxemia during one-lung ventilation (OLV) remains a serious problem, particularly in the supine position. We investigated the effects of alveolar recruitment (AR) and positive end-expiratory pressure (PEEP) on oxygenation during OLV in the supine position. Materials and Methods Ninety-nine patients were randomly allocated to one of the following three groups: a control group (ventilation with a tidal volume of 8 mL/kg), a PEEP group (the same ventilatory pattern with a PEEP of 8 cm H2O), or an AR group (an AR maneuver immediately before OLV followed by a PEEP of 8 cm H2O). The tidal volume was reduced to 6 mL/kg during OLV in all groups. Blood gas analyses, respiratory variables, and hemodynamic variables were recorded 15 min into TLV (TLVbaseline), 15 and 30 min after OLV (OLV15 and OLV30), and 10 min after re-establishing TLV (TLVend). Results Ultimately, 92 patients were analyzed. In the AR group, the arterial oxygen tension was higher at TLVend, and the physiologic dead space was lower at OLV15 and TLVend than in the control group. The mean airway pressure and dynamic lung compliance were higher in the PEEP and AR groups than in the control group at OLV15, OLV30, and TLVend. No significant differences in hemodynamic variables were found among the three groups throughout the study period. Conclusion Recruitment of both lungs with subsequent PEEP before OLV improved arterial oxygenation and ventilatory efficiency during video-assisted thoracic surgery requiring OLV in the supine position. PMID:26256990

  6. Prevention and management of pressure ulcers: support surfaces.

    PubMed

    Moore, Zena; Stephen Haynes, Jackie; Callaghan, Rosie

    Pressure ulcers are a common and debilitating problem in health care, impacting negatively on health-related quality of life and compounding challenges in achieving patient safety targets. Pressure ulcer prevention is a multidisciplinary team effort, involving a myriad of interventions, such as nutrition, skin care and repositioning. This article discusses the factors influencing pressure ulcer development, and then elaborates on the principles of prevention. This is followed by a focused discussion on the use of redistribution devices and the importance of the cover of such equipment in contributing to achieving good standards in prevention. PMID:24690750

  7. Effect of Time-dependent Pressure Boundary Condition on Flow Transport in a Patient Specific Lung Model during Invasive High Frequency Oscillatory Ventilation

    NASA Astrophysics Data System (ADS)

    Alzahrany, Mohammed; Banerjee, Arindam

    2013-11-01

    Large eddy simulation was used to investigate gas transport in a human lung (image-based) model during high frequency oscillatory ventilation (HFOV). A time-dependent pressure boundary condition as a function of the flow rate and coupled resistance-compliance was imposed at the outlets. The study was conducted for three different HFOV frequencies of 6, 10 and 15 Hz; a constant tidal volume of 50 ml and various compliance ratios (1, 4 and 10). The results are compared to computations that use traditional boundary conditions (such as pre-specified flow and constant pressure), experimental and gamma scintgraphy results. While traditional pre-specified mass fraction boundary condition failed to capture the Pendelluft flow at regional lung units that are observed in experiments, our modified resistance-compliance based pressure boundary condition was successful in predicting this feature. The impact of compliance ratio and frequency on phase-delay at different lung sections and its effect on secondary flow and turbulence will also be presented.

  8. [Variability of ventilation parameters of home ventilation equipment].

    PubMed

    Fuchs, M; Bickhardt, J; Morgenstern, U

    2002-01-01

    The performance of pressure- and volume controlled ventilators used for invasive and non-invasive ventilation in the home were tested on a patient lung model. In order to determine the influence of tidal volume preset, breathing rate, resistance, compliance and leakage to the variability of delivered tidal volume and peak airway pressure a factorial plan with adapted analysis of variance was used. The influence of tidal volume preset, compliance and leakage to the delivered tidal volume is significant. The peak airway pressure depends hardly on the influence factors. All tested ventilators meet the legal demands. But in some clinical situations there are considerable deviations of the breathing parameters depending on the brand. In conclusion ventilators of different brands are not interchangeable. PMID:12465320

  9. Tracheostomy and mechanical ventilation weaning in children affected by respiratory virus according to a weaning protocol in a pediatric intensive care unit in Argentina: an observational restrospective trial

    PubMed Central

    2011-01-01

    We describe difficult weaning after prolonged mechanical ventilation in three tracheostomized children affected by respiratory virus infection. Although the spontaneous breathing trials were successful, the patients failed all extubations. Therefore a tracheostomy was performed and the weaning plan was begun. The strategy for weaning was the decrease of ventilation support combining pressure control ventilation (PCV) with increasing periods of continuous positive airway pressure + pressure support ventilation (CPAP + PSV) and then CPAP + PSV with increasing intervals of T-piece. They presented acute respiratory distress syndrome on admission with high requirements of mechanical ventilation (MV). Intervening factors in the capabilities and loads of the respiratory system were considered and optimized. The average MV time was 69 days and weaning time 31 days. We report satisfactory results within the context of a directed weaning protocol. PMID:21244710

  10. Tracheostomy and mechanical ventilation weaning in children affected by respiratory virus according to a weaning protocol in a pediatric intensive care unit in Argentina: an observational restrospective trial.

    PubMed

    Caprotta, Gustavo; Crotti, Patricia Gonzalez; Frydman, Judith

    2011-01-01

    We describe difficult weaning after prolonged mechanical ventilation in three tracheostomized children affected by respiratory virus infection. Although the spontaneous breathing trials were successful, the patients failed all extubations. Therefore a tracheostomy was performed and the weaning plan was begun. The strategy for weaning was the decrease of ventilation support combining pressure control ventilation (PCV) with increasing periods of continuous positive airway pressure + pressure support ventilation (CPAP + PSV) and then CPAP + PSV with increasing intervals of T-piece. They presented acute respiratory distress syndrome on admission with high requirements of mechanical ventilation (MV). Intervening factors in the capabilities and loads of the respiratory system were considered and optimized. The average MV time was 69 days and weaning time 31 days.We report satisfactory results within the context of a directed weaning protocol. PMID:21244710

  11. Effects of Methadone on the Minimum Anesthetic Concentration of Isoflurane, and Its Effects on Heart Rate, Blood Pressure and Ventilation during Isoflurane Anesthesia in Hens (Gallus gallus domesticus)

    PubMed Central

    Pypendop, Bruno Henri; Zangirolami Filho, Darcio; Sousa, Samuel Santos; Valadão, Carlos Augusto Araújo

    2016-01-01

    The aim of this study was to measure the temporal effects of intramuscular methadone administration on the minimum anesthetic concentration (MAC) of isoflurane in hens, and to evaluate the effects of the isoflurane-methadone combination on heart rate and rhythm, blood pressure and ventilation. Thirteen healthy adult hens weighing 1.7 ± 0.2 kg were used. The MAC of isoflurane was determined in each individual using the bracketing method. Subsequently, the reduction in isoflurane MAC produced by methadone (3 or 6 mg kg-1, IM) was determined by the up-and-down method. Stimulation was applied at 15 and 30 minutes, and at 45 minutes if the bird had not moved at 30 minutes. Isoflurane MAC reduction was calculated at each time point using logistic regression. After a washout period, birds were anesthetized with isoflurane and methadone, 6 mg kg-1 IM was administered. Heart rate and rhythm, respiratory rate, blood gas values and invasive blood pressure were measured at 1.0 and 0.7 isoflurane MAC, and during 45 minutes after administration of methadone once birds were anesthetized with 0.7 isoflurane MAC. Fifteen minutes after administration of 3 mg kg-1 of methadone, isoflurane MAC was reduced by 2 (-9 to 13)% [logistic regression estimate (95% Wald confidence interval)]. Administration of 6 mg kg-1 of methadone decreased isoflurane MAC by 29 (11 to 46)%, 27 (-3 to 56)% and 10 (-8 to 28)% after 15, 30 and 45 minutes, respectively. Methadone (6 mg kg-1) induced atrioventricular block in three animals and ventricular premature contractions in two. Methadone caused an increase in arterial blood pressure and arterial partial pressure of carbon dioxide, while heart rate and pH decreased. Methadone, 6 mg kg-1 IM significantly reduced isoflurane MAC by 30% in hens 15 minutes after administration. At this dose, methadone caused mild respiratory acidosis and increase in systemic blood pressure. PMID:27018890

  12. Partial blood oxygen pressure and pulmonary ventilation changes in patients with fractures with a view to traumatic fat embolism development.

    PubMed

    Kroupa, J; Kusák, I

    1983-01-01

    The body's response to the effects of mechanical injury, taking the form of shock during the first hours and the onset of fat embolism in the subsequent period, is substantially higher in patients with multiple or associated injuries, both as regards the severity of manifestations and prognostic risk. Also the death rate due to this sort of complication is seen rising. Two groups of injured persons with isolated (n = 33) and multiple fractures (n = 33) were used to show that dynamic follow-up of PaO2 in the blood could serve as a criterion of the risk of fat embolism development in the body and, in particular, as a prognostic criterion for the progress of fat embolism. Special point was made of findings demonstrating a time relationship between PaO2 deterioration in the early post-injury period (up to 24-36 hours) as compared with the period of 48-72 hours after the injury. PaO2 is seen dropping rapidly in injured persons showing signs of fat embolism syndrome development. The decrease can be recorded as early as the free interval phase, i.e. prior to the manifestation of the clinical signs of fat embolism. The findings of low PaO2 levels in the blood are in accordance with respiratory ventilation disturbances and impaired diffusion documented in our investigation. PMID:6409565

  13. Design and Development of a Regenerative Blower for Space Suit Ventilation

    NASA Technical Reports Server (NTRS)

    Izenson, Mike; Chen, Weibo; Paul, Heather

    2010-01-01

    The ventilation subsystem in future space suits will require a dedicated ventilation fan. The unique requirements for the ventilation fan, including stringent safety requirements and the ability to increase output to operate in buddy mode, combine to make a regenerative blower an attractive technology choice. This paper describes progress in the design, development, and testing of a regenerative blower designed to meet requirements for a ventilation subsystem for future space suit life support. Analysis methods were developed for the blower s complex internal flows and impeller geometries were identified that enable significant improvements in blower efficiency. Performance predictions were verified by test, measuring aerodynamic efficiencies of 45% at operating conditions that correspond to the ventilation fan s design point. A compact motor/controller was developed to drive the blower efficiently at low rotating speed (4500 rpm). Finally, a low-pressure oxygen test loop was assembled to demonstrate the blower s reliability under prototypical conditions.

  14. Optimizing ventilation in conjunction with phased chest and abdominal compression-decompression (Lifestick) resuscitation.

    PubMed

    Kern, Karl B; Hilwig, Ronald W; Berg, Robert A; Schock, Robert B; Ewy, Gordon A

    2002-01-01

    The best method for employment of phased chest and abdominal compression-decompression (Lifestick) cardiopulmonary resuscitation (CPR) has yet to be determined. Of particular concern with using this technique is the combining of ventilation with the phased compressions and decompressions. Twenty domestic swine (50+/-1 kg) were equally divided into four groups. Following 10 min of untreated VF, CPR was begun. Group 1 received Lifestick (LS) CPR with only passive ventilation ('passive'); Group 2 received LS-CPR with synchronized positive pressure ventilations (ppv) at a chest compression ratio of 15:2 (15:2 S); Group 3 had LS-CPR with synchronized ppv at 5:1 (5:1 S); and Group 4 received LS-CPR with asynchronous ppv at 5:1 (5:1 A). Endpoints included hemodynamics, blood gases, minute ventilation, and 24 h outcome. Asynchronous ventilation (5:1 A) had significantly worse hemodynamics including aortic and right atrial systolic, aortic diastolic, and coronary perfusion pressures than the other groups (P<0.05). Passive ventilation had the poorest arterial and mixed venous blood gases (P<0.05), but did not differ from 15:2 S in minute ventilation produced (8 vs 10 l/min). No differences in outcome were seen. The ventilation technique combined with LS-CPR can make a significant difference in hemodynamics as well as ventilation. Optimizing other forms of basic and advanced cardiac life support through different ventilation methods deserves new consideration, including a re-examination of the current single rescuer recommendation of a 15:2 ratio. Optimal ventilation strategy when using the LS device at 60 compressions per min appears to be 5:1 S. Such data is important for conducting clinical trials with this new CPR adjunct. PMID:11801354

  15. 46 CFR 42.15-45 - Ventilators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... any ventilator exceeds 351/2 inches in height it shall be specially supported. (b) Ventilators passing.... Ventilators in position 1 shall have coamings of a height of at least 351/2 inches above the deck; in position 2 the coamings shall be of a height at least 30 inches above the deck. (e) In exposed positions,...

  16. 46 CFR 42.15-45 - Ventilators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... any ventilator exceeds 351/2 inches in height it shall be specially supported. (b) Ventilators passing.... Ventilators in position 1 shall have coamings of a height of at least 351/2 inches above the deck; in position 2 the coamings shall be of a height at least 30 inches above the deck. (e) In exposed positions,...

  17. 46 CFR 42.15-45 - Ventilators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... any ventilator exceeds 351/2 inches in height it shall be specially supported. (b) Ventilators passing.... Ventilators in position 1 shall have coamings of a height of at least 351/2 inches above the deck; in position 2 the coamings shall be of a height at least 30 inches above the deck. (e) In exposed positions,...

  18. 46 CFR 42.15-45 - Ventilators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... any ventilator exceeds 351/2 inches in height it shall be specially supported. (b) Ventilators passing.... Ventilators in position 1 shall have coamings of a height of at least 351/2 inches above the deck; in position 2 the coamings shall be of a height at least 30 inches above the deck. (e) In exposed positions,...

  19. 46 CFR 42.15-45 - Ventilators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... any ventilator exceeds 351/2 inches in height it shall be specially supported. (b) Ventilators passing.... Ventilators in position 1 shall have coamings of a height of at least 351/2 inches above the deck; in position 2 the coamings shall be of a height at least 30 inches above the deck. (e) In exposed positions,...

  20. Preemptive mechanical ventilation can block progressive acute lung injury

    PubMed Central

    Sadowitz, Benjamin; Jain, Sumeet; Kollisch-Singule, Michaela; Satalin, Joshua; Andrews, Penny; Habashi, Nader; Gatto, Louis A; Nieman, Gary

    2016-01-01

    Mortality from acute respiratory distress syndrome (ARDS) remains unacceptable, approaching 45% in certain high-risk patient populations. Treating fulminant ARDS is currently relegated to supportive care measures only. Thus, the best treatment for ARDS may lie with preventing this syndrome from ever occurring. Clinical studies were examined to determine why ARDS has remained resistant to treatment over the past several decades. In addition, both basic science and clinical studies were examined to determine the impact that early, protective mechanical ventilation may have on preventing the development of ARDS in at-risk patients. Fulminant ARDS is highly resistant to both pharmacologic treatment and methods of mechanical ventilation. However, ARDS is a progressive disease with an early treatment window that can be exploited. In particular, protective mechanical ventilation initiated before the onset of lung injury can prevent the progression to ARDS. Airway pressure release ventilation (APRV) is a novel mechanical ventilation strategy for delivering a protective breath that has been shown to block progressive acute lung injury (ALI) and prevent ALI from progressing to ARDS. ARDS mortality currently remains as high as 45% in some studies. As ARDS is a progressive disease, the key to treatment lies with preventing the disease from ever occurring while it remains subclinical. Early protective mechanical ventilation with APRV appears to offer substantial benefit in this regard and may be the prophylactic treatment of choice for preventing ARDS. PMID:26855896

  1. Preemptive mechanical ventilation can block progressive acute lung injury.

    PubMed

    Sadowitz, Benjamin; Jain, Sumeet; Kollisch-Singule, Michaela; Satalin, Joshua; Andrews, Penny; Habashi, Nader; Gatto, Louis A; Nieman, Gary

    2016-02-01

    Mortality from acute respiratory distress syndrome (ARDS) remains unacceptable, approaching 45% in certain high-risk patient populations. Treating fulminant ARDS is currently relegated to supportive care measures only. Thus, the best treatment for ARDS may lie with preventing this syndrome from ever occurring. Clinical studies were examined to determine why ARDS has remained resistant to treatment over the past several decades. In addition, both basic science and clinical studies were examined to determine the impact that early, protective mechanical ventilation may have on preventing the development of ARDS in at-risk patients. Fulminant ARDS is highly resistant to both pharmacologic treatment and methods of mechanical ventilation. However, ARDS is a progressive disease with an early treatment window that can be exploited. In particular, protective mechanical ventilation initiated before the onset of lung injury can prevent the progression to ARDS. Airway pressure release ventilation (APRV) is a novel mechanical ventilation strategy for delivering a protective breath that has been shown to block progressive acute lung injury (ALI) and prevent ALI from progressing to ARDS. ARDS mortality currently remains as high as 45% in some studies. As ARDS is a progressive disease, the key to treatment lies with preventing the disease from ever occurring while it remains subclinical. Early protective mechanical ventilation with APRV appears to offer substantial benefit in this regard and may be the prophylactic treatment of choice for preventing ARDS. PMID:26855896

  2. Stem Photosynthesis not Pressurized Ventilation is Responsible for Light-enhanced Oxygen Supply to Submerged Roots of Alder (Alnus glutinosa)

    PubMed Central

    ARMSTRONG, WILLIAM; ARMSTRONG, JEAN

    2005-01-01

    • Background and Aims Claims that submerged roots of alder and other wetland trees are aerated by pressurized gas flow generated in the stem by a light-induced thermo-osmosis have seemed inconsistent with root anatomy. Our aim was to seek a verification using physical root–stem models, stem segments with or without artificial roots, and rooted saplings. • Methods Radial O2 loss (ROL) from roots was monitored polarographically as the gas space system of the models, and stems were pressurized artificially. ROL and internal pressurization were also measured when stems were irradiated and the xylem stream was either CO2 enriched or not. Stem photosynthesis and respiration were measured polarographically. Stem and root anatomy were examined by light and fluorescence microscopy. • Key Results Pressurizing the models and stems to ≤10 kPa, values much higher than those reportedly generated by thermo-osmosis, created only a negligible density-induced increase in ROL, but ROL increased rapidly when ambient O2 concentrations were raised. Internal pressures rose by several kPa when shoots were exposed to high light flux and ROL increased substantially, but both were due to O2 accumulation from stem photosynthesis using internally sourced CO2. Increased stem pressures had little effect on O2 transport, which remained largely diffusive. Oxygen flux from stems in high light periods indicated a net C gain by stem photosynthesis. Chloroplasts were abundant in the secondary cortex and secondary phloem, and occurred throughout the secondary xylem rays and medulla of 3-year-old stems. Diurnal patterns of ROL, most marked when light reached submerged portions of the stem, were modified by minor variations in light flux and water level. Low root temperatures also helped improve root aeration. • Conclusions Pressurized gas flow to submerged roots does not occur to any significant degree in alder, but stem photosynthesis, using internally sourced CO2 from respiration and the

  3. Mechanical support of the pressure overloaded right ventricle: an acute feasibility study comparing low and high flow support.

    PubMed

    Verbelen, Tom; Verhoeven, Jelle; Goda, Motohiko; Burkhoff, Daniel; Delcroix, Marion; Rega, Filip; Meyns, Bart

    2015-08-15

    The objectives of this study were to assess the feasibility of low flow right ventricular support and to describe the hemodynamic effects of low versus high flow support in an animal model of acute right ventricular pressure overload. A Synergy Pocket Micro-pump (HeartWare International, Framingham, MA) was implanted in seven sheep. Blood was withdrawn from the right atrium to the pulmonary artery. Hemodynamics and pressure-volume loops were recorded in baseline conditions, after banding the pulmonary artery, and after ligating the right coronary artery in these banded sheep. End-organ perfusion (reflected by total cardiac output and arterial blood pressure) improved in all conditions. Intrinsic right ventricular contractility was not significantly impacted by support. Diastolic unloading of the pressure overloaded right ventricle (reflected by decreases in central venous pressure, end-diastolic pressure and volume, and ventricular capacitance) was successful, but with a concomitant and flow-dependent increase of the systolic afterload. This unloading diminished with right ventricular ischemia. Right ventricular mechanical support improves arterial blood pressure and cardiac output. It provides diastolic unloading of the right ventricle, but with a concomitant and right ventricular assist device flow-dependent increase of systolic afterload. These effects are most distinct in the pressure overloaded right ventricle without profound ischemic damage. We advocate the low flow strategy, which is potentially beneficial for the afterload sensitive right ventricle and has the advantage of avoiding excessive increases in pulmonary artery pressure when pulmonary hypertension exists. This might protect against the development of pulmonary edema and hemorrhage. PMID:26071544

  4. Noninvasive ventilation in acute respiratory failure

    PubMed Central

    Mas, Arantxa; Masip, Josep

    2014-01-01

    After the institution of positive-pressure ventilation, the use of noninvasive ventilation (NIV) through an interface substantially increased. The first technique was continuous positive airway pressure; but, after the introduction of pressure support ventilation at the end of the 20th century, this became the main modality. Both techniques, and some others that have been recently introduced and which integrate some technological innovations, have extensively demonstrated a faster improvement of acute respiratory failure in different patient populations, avoiding endotracheal intubation and facilitating the release of conventional invasive mechanical ventilation. In acute settings, NIV is currently the first-line treatment for moderate-to-severe chronic obstructive pulmonary disease exacerbation as well as for acute cardiogenic pulmonary edema and should be considered in immunocompromised patients with acute respiratory insufficiency, in difficult weaning, and in the prevention of postextubation failure. Alternatively, it can also be used in the postoperative period and in cases of pneumonia and asthma or as a palliative treatment. NIV is currently used in a wide range of acute settings, such as critical care and emergency departments, hospital wards, palliative or pediatric units, and in pre-hospital care. It is also used as a home care therapy in patients with chronic pulmonary or sleep disorders. The appropriate selection of patients and the adaptation to the technique are the keys to success. This review essentially analyzes the evidence of benefits of NIV in different populations with acute respiratory failure and describes the main modalities, new devices, and some practical aspects of the use of this technique. PMID:25143721

  5. Specific dimensions of perceived support and ambulatory blood pressure: which support functions appear most beneficial and for whom?

    PubMed

    Bowen, Kimberly S; Birmingham, Wendy; Uchino, Bert N; Carlisle, McKenzie; Smith, Timothy W; Light, Kathleen C

    2013-06-01

    Perceived support has been related to lower cardiovascular morbidity and mortality. However, little is known about the specific functional components of support responsible for such links. We tested if emotional, informational, tangible, and belonging support predicted ambulatory blood pressure (ABP) and interpersonal interactions (e.g., responsiveness), and if such links were moderated by gender. In this study, 94 married couples underwent 12 h of ABP monitoring during daily life which included a night at home with their spouse. They completed a short-form of the interpersonal support evaluation list that provides information on total (global) support, as well as specific dimensions of support. Results revealed that global support scores did not predict ABP during daily life. However, separating out distinct support components revealed that emotional support was a significant predictor of lower ambulatory systolic and diastolic blood pressure, primarily for women. Finally, emotional support predicted greater partner responsiveness and self-disclosure, along with less perceived partner negativity although these results were not moderated by gender. These data are discussed in terms of the importance of considering specific support components and the contextual processes that might influence such links. PMID:22465206

  6. Subsurface Ventilation System Description Document

    SciTech Connect

    Eric Loros

    2001-07-25

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  7. Subsurface Ventilation System Description Document

    SciTech Connect

    2000-10-12

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  8. [Home mechanical ventilation-tracheostomy ventilation, for the long-term and variation].

    PubMed

    Yamamoto, Makoto

    2006-12-01

    We experienced long-term ventilation for 30 patients mostly with amyotrophic lateral sclerosis (ALS). For long-term ventilation by tracheostomy positive pressure ventilation (TPPV), we must set tidal volume (TV) over 600 ml, because setting 400 ml as TV usually applied in Japan, often develops atelectasis which causes frequent or serious pneumonia. To avoid both the elevation of airway pressure and hyper ventilation, the following intervals are needed: 10 times/min for breathing frequency and 2 seconds for exhaling time. In the cases with ventilator induced lung injury (VILI), it is necessary to lower the TV and to treat with steroid pulse therapy. In the transitional stage from non-invasive positive pressure ventilation (NPPV) to TPPV, we conduct tracheostomy for suction of the sputum. In that stage, by using a cuffless tracheal canule, we can continue NPPV. As another method in that stage, we recommend biphasic management by NPPV at daytime and TPPV at nighttime with a bi-level ventilator. This method can provide certain ventilation also during sleep. When the respiratory failure proceeds further, we manage the ventilation with a bi-level ventilator on TPPV, because a bi-level ventilator is also good adapting to assist spontaneous breathing in that stage. And if the patient does not have bulbar paralysis, the patient can utter by air leakage with using bi-level ventilator and flattening the cuff of the tracheal canule. PMID:17469348

  9. Increasing pressures and support for public healthcare in Europe.

    PubMed

    Jensen, Carsten; Naumann, Elias

    2016-06-01

    We present the results from a natural survey-experiment that tests the effect of a sudden increase in health risks - a flu epidemic - on the public's support for government involvement in health care provision. The data covers 17 European countries and around 10,000 respondents. It was collected in 2008 as part of the European Social Survey. We find that the flu epidemic led to a significant decline in support. Interestingly, changes where located predominantly among those respondents that are self-described right-leaning in ideological terms. The effects of the flu epidemic lasted several weeks and in some instances persisted as long as it was possible to track with the data (i.e., a month). Given that this was a single-event stimulus such a comparably long-lasting effect is noteworthy for both public policy-makers and political scientists. PMID:27166022

  10. Lunar Surface Scenarios: Habitation and Life Support Systems for a Pressurized Rover

    NASA Technical Reports Server (NTRS)

    Anderson, Molly; Hanford, Anthony; Howard, Robert; Toups, Larry

    2006-01-01

    Pressurized rovers will be a critical component of successful lunar exploration to enable safe investigation of sites distant from the outpost location. A pressurized rover is a complex system with the same functions as any other crewed vehicle. Designs for a pressurized rover need to take into account significant constraints, a multitude of tasks to be performed inside and out, and the complexity of life support systems to support the crew. In future studies, pressurized rovers should be given the same level of consideration as any other vehicle occupied by the crew.

  11. Inhalation therapy in mechanical ventilation

    PubMed Central

    Maccari, Juçara Gasparetto; Teixeira, Cassiano; Gazzana, Marcelo Basso; Savi, Augusto; Dexheimer-Neto, Felippe Leopoldo; Knorst, Marli Maria

    2015-01-01

    Patients with obstructive lung disease often require ventilatory support via invasive or noninvasive mechanical ventilation, depending on the severity of the exacerbation. The use of inhaled bronchodilators can significantly reduce airway resistance, contributing to the improvement of respiratory mechanics and patient-ventilator synchrony. Although various studies have been published on this topic, little is known about the effectiveness of the bronchodilators routinely prescribed for patients on mechanical ventilation or about the deposition of those drugs throughout the lungs. The inhaled bronchodilators most commonly used in ICUs are beta adrenergic agonists and anticholinergics. Various factors might influence the effect of bronchodilators, including ventilation mode, position of the spacer in the circuit, tube size, formulation, drug dose, severity of the disease, and patient-ventilator synchrony. Knowledge of the pharmacological properties of bronchodilators and the appropriate techniques for their administration is fundamental to optimizing the treatment of these patients. PMID:26578139

  12. Mechanical Ventilation

    MedlinePlus

    ... or husband or next of kin). It is important that you talk with your family members and your doctors about using a ventilator and what you would like to happen in different situations. The more clearly you explain your values and choices to friends, loved ones and doctors, ...

  13. Preventing Ventilation On Sailboard Skegs

    NASA Technical Reports Server (NTRS)

    Caldwell, Richard A.

    1990-01-01

    Design effort undertaken to solve spinout problem plaguing high-performance sailboards. Proposed skeg section designed by use of computer model of pressure field and boundary layer. Prevents ventilation by maintaining attached boundary-layer flow throughout operating environment. Cavitation also avoided by preventing valleys in pressure distribution while skeg operated throughout its range.

  14. Oxygen utilization and the branchial pressure gradient during ram ventilation of the shortfin mako, Isurus oxyrinchus: is lamnid shark-tuna convergence constrained by elasmobranch gill morphology?

    PubMed

    Wegner, Nicholas C; Lai, N Chin; Bull, Kristina B; Graham, Jeffrey B

    2012-01-01

    Ram ventilation and gill function in a lamnid shark, the shortfin mako, Isurus oxyrinchus, were studied to assess how gill structure may affect the lamnid-tuna convergence for high-performance swimming. Despite differences in mako and tuna gill morphology, mouth gape and basal swimming speeds, measurements of mako O(2) utilization at the gills (53.4±4.2%) and the pressure gradient driving branchial flow (96.8±26.1 Pa at a mean swimming speed of 38.8±5.8 cm s(-1)) are similar to values reported for tunas. Also comparable to tunas are estimates of the velocity (0.22±0.03 cm s(-1)) and residence time (0.79±0.14 s) of water though the interlamellar channels of the mako gill. However, mako and tuna gills differ in the sites of primary branchial resistance. In the mako, approximately 80% of the total branchial resistance resides in the septal channels, structures inherent to the elasmobranch gill that are not present in tunas. The added resistance at this location is compensated by a correspondingly lower resistance at the gill lamellae accomplished through wider interlamellar channels. Although greater interlamellar spacing minimizes branchial resistance, it also limits lamellar number and results in a lower total gill surface area for the mako relative to tunas. The morphology of the elasmobranch gill thus appears to constrain gill area and, consequently, limit mako aerobic performance to less than that of tunas. PMID:22162850

  15. Differential Effects of Endotracheal Suctioning on Gas Exchanges in Patients with Acute Respiratory Failure under Pressure-Controlled and Volume-Controlled Ventilation.

    PubMed

    Liu, Xiao-Wei; Jin, Yan; Ma, Tao; Qu, Bo; Liu, Zhi

    2015-01-01

    This study was conducted to evaluate the effects of open endotracheal suctioning on gas exchange and respiratory mechanics in ARF patients under the modes of PCV or VCV. Ninety-six ARF patients were treated with open endotracheal suctioning and their variations in respiratory mechanics and gas exchange after the suctions were compared. Under PCV mode, compared with the initial level of tidal volume (V T ), ARF patients showed 30.0% and 27.8% decrease at 1 min and 10 min, respectively. Furthermore, the initial respiratory system compliance (C rs) decreased by 29.6% and 28.5% at 1 min and 10 min, respectively. Under VCV mode, compared with the initial level, 38.6% and 37.5% increase in peak airway pressure (PAP) were found at 1 min and 10 min, respectively. Under PCV mode, the initial PaO2 increased by 6.4% and 10.2% at 3 min and 10 min, respectively, while 18.9% and 30.6% increase of the initial PaO2 were observed under VCV mode. Summarily, endotracheal suctioning may impair gas exchange and decrease lung compliance in ARF patients receiving mechanical ventilation under both PCV and VCV modes, but endotracheal suctioning effects on gas exchange were more severe and longer-lasting under PCV mode than VCV. PMID:25954759

  16. Differential Effects of Endotracheal Suctioning on Gas Exchanges in Patients with Acute Respiratory Failure under Pressure-Controlled and Volume-Controlled Ventilation

    PubMed Central

    Liu, Xiao-Wei; Jin, Yan; Ma, Tao; Qu, Bo; Liu, Zhi

    2015-01-01

    This study was conducted to evaluate the effects of open endotracheal suctioning on gas exchange and respiratory mechanics in ARF patients under the modes of PCV or VCV. Ninety-six ARF patients were treated with open endotracheal suctioning and their variations in respiratory mechanics and gas exchange after the suctions were compared. Under PCV mode, compared with the initial level of tidal volume (VT), ARF patients showed 30.0% and 27.8% decrease at 1 min and 10 min, respectively. Furthermore, the initial respiratory system compliance (Crs) decreased by 29.6% and 28.5% at 1 min and 10 min, respectively. Under VCV mode, compared with the initial level, 38.6% and 37.5% increase in peak airway pressure (PAP) were found at 1 min and 10 min, respectively. Under PCV mode, the initial PaO2 increased by 6.4% and 10.2 % at 3 min and 10 min, respectively, while 18.9% and 30.6% increase of the initial PaO2 were observed under VCV mode. Summarily, endotracheal suctioning may impair gas exchange and decrease lung compliance in ARF patients receiving mechanical ventilation under both PCV and VCV modes, but endotracheal suctioning effects on gas exchange were more severe and longer-lasting under PCV mode than VCV. PMID:25954759

  17. High frequency jet ventilation in fat embolism syndrome.

    PubMed

    Lee, A; Simpson, D

    1986-11-01

    The use of high frequency jet ventilation in the management of a patient with fat embolism syndrome is described. Its principal advantage over conventional intermittent positive pressure ventilation is a reduction in the amount of sedation necessary. PMID:3789371

  18. Inner Space and Outer Space: Pressure Suits & Life Support Systems for Space Workers

    NASA Technical Reports Server (NTRS)

    Webbon, Bruce

    2004-01-01

    This slide presentation presents an overview of work system requirements, extravehicular activity system evolution, key issues, future needs, and a summary. Key issues include pressure suits, life support systems, system integration, biomedical requirements, and work and mobility aids.

  19. Pressure ulcers and nutritional support: a partnership to improve patient outcomes.

    PubMed

    Barrett, Roseann; Tuttle, Virginia; Whalen, Elizabeth; Gatchell, Carolyn; Dawe, Amy

    2010-01-01

    Prevention of pressure ulcers in hospitalized patients represents a challenge with great financial impact for hospitals and serious consequences for patients. A partnership composed of dieticians and nurses was assembled to identify best practices for providing nutritional support and intervention to patients at risk for pressure ulcers. This article describes the process, outcomes, recommendations, and lessons learned by the pressure ulcer/nutrition work group. PMID:19707154

  20. The 12-foot pressure wind tunnel restoration project model support systems

    NASA Technical Reports Server (NTRS)

    Sasaki, Glen E.

    1992-01-01

    The 12 Foot Pressure Wind Tunnel is a variable density, low turbulence wind tunnel that operates at subsonic speeds, and up to six atmospheres total pressure. The restoration of this facility is of critical importance to the future of the U.S. aerospace industry. As part of this project, several state of the art model support systems are furnished to provide an optimal balance between aerodynamic and operational efficiency parameters. Two model support systems, the Rear Strut Model Support, and the High Angle of Attack Model Support are discussed. This paper covers design parameters, constraints, development, description, and component selection.

  1. Non invasive ventilation as an additional tool for exercise training.

    PubMed

    Ambrosino, Nicolino; Cigni, Paolo

    2015-01-01

    Recently, there has been increasing interest in the use of non invasive ventilation (NIV) to increase exercise capacity. In individuals with COPD, NIV during exercise reduces dyspnoea and increases exercise tolerance. Different modalities of mechanical ventilation have been used non-invasively as a tool to increase exercise tolerance in COPD, heart failure and lung and thoracic restrictive diseases. Inspiratory support provides symptomatic benefit by unloading the ventilatory muscles, whereas Continuous Positive Airway Pressure (CPAP) counterbalances the intrinsic positive end-expiratory pressure in COPD patients. Severe stable COPD patients undergoing home nocturnal NIV and daytime exercise training showed some benefits. Furthermore, it has been reported that in chronic hypercapnic COPD under long-term ventilatory support, NIV can also be administered during walking. Despite these results, the role of NIV as a routine component of pulmonary rehabilitation is still to be defined. PMID:25874110

  2. Effects of chemical feedback on respiratory motor and ventilatory output during different modes of assisted mechanical ventilation.

    PubMed

    Mitrouska, J; Xirouchaki, N; Patakas, D; Siafakas, N; Georgopoulos, D

    1999-04-01

    The purpose of the study was to examine the effects of chemical feedback on respiratory motor and ventilatory output in conscious subjects ventilated on various modes of assisted mechanical ventilation. Seven subjects were connected to a ventilator and randomly ventilated on assist-volume control (AVC), pressure support (PS) or proportional assist ventilation (PAV). On each mode, the assist level was set to the highest comfortable level. Airway and oesophageal (Poes) pressures, tidal volume, respiratory frequency (fR) and end-tidal carbon dioxide tension (PET,CO2) were measured breath-by-breath. When the subjects were stable on each mode, the fraction of inspired carbon dioxide (FI,CO2) was increased stepwise, and changes in minute ventilation (V'E) and respiratory motor output, estimated by the pressure-time product of all the respiratory muscles per breath (PTPrm) and per minute (PTPminute), were observed. At zero FI,CO2, PTPminute/PET,CO2 did not differ between modes, while V'E/ PTPminute was significantly lower with PAV than that with PS and AVC. As a result V'E/PET,CO2 was significantly lower with PAV, preventing, unlike AVC and PS, a significant drop in PET,CO2. With PAV, independent of CO2, V'E/PTPminute remained constant, while it decreased significantly with increasing CO2 stimulus with PS and AVC. At high PET,CO2 respiratory effort was significantly lower with PAV than that with PS and AVC. In conclusion, the mode of mechanical ventilation modifies the effects of chemical feedback on respiratory motor and ventilatory output. At all carbon dioxide stimulus levels neuroventilatory coupling was better preserved with proportional assist ventilation than with pressure support and assist-volume control ventilation. PMID:10362056

  3. Echocardiography in a Patient on Mechanical Ventilation.

    PubMed

    Sachdeva, Ankush

    2015-07-01

    Cardiopulmonary interactions or effects of spontaneous and mechanical ventilation (MV) were first documented in the year 1733. Stephen Hales showed that the blood pressure of healthy individual fell during spontaneous inspiration and he later went on to discover the ventilator. A year later Kussmaul described pulsus paradoxus (inspiratory absence of radial pulse) in patients with tubercular pericarditis. Echocardiography can help to diagnose a wide variety of cardiovascular diseases and can guide therapeutic decisions in patients on mechanical ventilation. PMID:26731826

  4. Transpleural Ventilation via Spiracles in Severe Emphysema Increases Alveolar Ventilation.

    PubMed

    Chahla, Mayy; Larson, Christopher D; Parekh, Kalpaj R; Reed, Robert M; Terry, Peter; Schmidt, Gregory A; Eberlein, Michael

    2016-06-01

    In emphysema airway resistance can exceed collateral airflow resistance, causing air to flow preferentially through collateral pathways. In severe emphysema ventilation through openings directly through the chest wall into the parenchyma (spiracles) could bypass airway obstruction and increase alveolar ventilation via transpleural expiration. During lung transplant operations, spiracles occasionally can occur inadvertently. We observed transpleural expiration via spiracles in three subjects undergoing lung transplant for emphysema. During transpleural spiracle ventilation, inspiratory tidal volumes (TV) were unchanged; however, expiration was entirely transpleural in two patients whereas the expired TV to the ventilator circuit was reduced to 25% of the inspired TV in one. At baseline, mean PCO2 was 61 ± 5 mm Hg, which decreased to a mean PCO2 of 49 ± 5 mm Hg (P = .05) within minutes after transpleural spiracle ventilation and further decreased at 1 to 2 h (36 ± 4 mm Hg; P = .002 compared with baseline) on unchanged ventilator settings. This observation of increased alveolar ventilation supports further studies of spiracles as a possible therapy for advanced emphysema. PMID:27287591

  5. DEVELOPMENT AND DEMONSTRATION OF A PILOT SCALE FACILITY FOR FABRICATION AND MARKETING OF LIGHTWEIGHT-COAL COMBUSTION BYPRODUCTS-BASED SUPPORTS AND MINE VENTILATION BLOCKS FOR UNDERGROUND MINES

    SciTech Connect

    Yoginder P. Chugh

    2002-10-01

    The overall goal of this program was to develop a pilot scale facility, and design, fabricate, and market CCBs-based lightweight blocks for mine ventilation control devices, and engineered crib elements and posts for use as artificial supports in underground mines to replace similar wooden elements. This specific project was undertaken to (1) design a pilot scale facility to develop and demonstrate commercial production techniques, and (2) provide technical and marketing support to Fly Lite, Inc to operate the pilot scale facility. Fly Lite, Inc is a joint venture company of the three industrial cooperators who were involved in research into the development of CCBs-based structural materials. The Fly-Lite pilot scale facility is located in McLeansboro, Illinois. Lightweight blocks for use in ventilation stoppings in underground mines have been successfully produced and marketed by the pilot-scale facility. To date, over 16,000 lightweight blocks (30-40 pcf) have been sold to the mining industry. Additionally, a smaller width (6-inch) full-density block was developed in August-September 2002 at the request of a mining company. An application has been submitted to Mine Safety and Health Administration for the developed block approval for use in mines. Commercialization of cribs and posts has also been accomplished. Two generations of cribs have been developed and demonstrated in the field. MSHA designated them suitable for use in mines. To date, over 2,000 crib elements have been sold to mines in Illinois. Two generations of posts were also demonstrated in the field and designated as suitable for use in mines by MSHA. Negotiations are currently underway with a mine in Illinois to market about 1,000 posts per year based on a field demonstration in their mine. It is estimated that 4-5 million tons CCBs (F-fly ash or FBC fly ash) may be utilized if the developed products can be commercially implemented in U.S. coal and non-coal mines.

  6. Early Surfactant Therapy With Nasal Continuous Positive Airway Pressure or Continued Mechanical Ventilation in Very Low Birth Weight Neonates With Respiratory Distress Syndrome

    PubMed Central

    Najafian, Bita; Fakhraie, Seyed Hasan; Afjeh, Seyed Abulfazl; Kazemian, Mohammad; Shohrati, Majid; Saburi, Amin

    2014-01-01

    Background: Various strategies have been suggested for the treatment of respiratory distress syndrome (RDS). Objectives: The aim of this study was to compare the efficacies of two common methods of RDS management among neonates with low birth weight. Patients and Methods: A cohort study was conducted on 98 neonates with definite diagnosis of RDS during 2008-2009. The neonates were divided into two groups by a blinded supervisor using simple randomization (odd and even numbers). Forty-five cases in the first group were treated with intubation, surfactant therapy, extubation (INSURE method) followed by nasal continuous positive airway pressure (N.CPAP) and 53 cases in the second group underwent intubation, surfactant therapy followed by mechanical ventilation (MV). Results: Five (11.1%) cases in the first group and 23 (43%) cases in the second group expired during the study. The rates of MV dependency among cases with INSURE failure and cases in the MV group were 37% and 83%, respectively (P < 0.001). Birth weight (BW) (P = 0.017), presence of retinopathy of prematurity (P = 0.022), C/S delivery (P = 0.029) and presence of lung bleeding (P = 0.010) could significantly predict mortality in the second group, although only BW (P = 0.029) had a significant impact on the mortality rate in the first group. Moreover, BW was significantly related to the success rate in the first group (P = 0.001). Conclusions: Our findings demonstrated that INSURE plus NCPAP was more effective than the routine method (permanent intubation after surfactant prescription). In addition, the lower rates of mortality, MV dependency, duration of hospitalization, and complications were observed in cases treated with the INSURE method compared to the routine one. PMID:24910785

  7. [BiPAP (Biphasic Positive Airway Pressure)--an apparatus for non-invasive respiratory support].

    PubMed

    Nørregaard, F O; Vindelev, P O; Juhl, B

    1996-01-22

    Ventilatory support to patients suffering from respiratory insufficiency using a non-invasive technique has gained increasing popularity during the last few years. BiPAP (biphasic positive airway pressure) (Respiconics) offers inspiratory support and expiratory resistance to this group of patients both in the hospital and, in particular, in the home. The apparatus has proven to be effective as for instance a long term support device for patients suffering from neuromuscular diseases, sleep apnoeas and during the postoperative period. It works without pressurized air and is portable. PMID:8638299

  8. Real time noninvasive estimation of work of breathing using facemask leak-corrected tidal volume during noninvasive pressure support: validation study.

    PubMed

    Banner, Michael J; Tams, Carl G; Euliano, Neil R; Stephan, Paul J; Leavitt, Trevor J; Martin, A Daniel; Al-Rawas, Nawar; Gabrielli, Andrea

    2016-06-01

    We describe a real time, noninvasive method of estimating work of breathing (esophageal balloon not required) during noninvasive pressure support (PS) that uses an artificial neural network (ANN) combined with a leak correction (LC) algorithm, programmed to ignore asynchronous breaths, that corrects for differences in inhaled and exhaled tidal volume (VT) from facemask leaks (WOBANN,LC/min). Validation studies of WOBANN,LC/min were performed. Using a dedicated and popular noninvasive ventilation ventilator (V60, Philips), in vitro studies using PS (5 and 10 cm H2O) at various inspiratory flow rate demands were simulated with a lung model. WOBANN,LC/min was compared with the actual work of breathing, determined under conditions of no facemask leaks and estimated using an ANN (WOBANN/min). Using the same ventilator, an in vivo study of healthy adults (n = 8) receiving combinations of PS (3-10 cm H2O) and expiratory positive airway pressure was done. WOBANN,LC/min was compared with physiologic work of breathing/min (WOBPHYS/min), determined from changes in esophageal pressure and VT applied to a Campbell diagram. For the in vitro studies, WOBANN,LC/min and WOBANN/min ranged from 2.4 to 11.9 J/min and there was an excellent relationship between WOBANN,LC/breath and WOBANN/breath, r = 0.99, r(2) = 0.98 (p < 0.01). There were essentially no differences between WOBANN,LC/min and WOBANN/min. For the in vivo study, WOBANN,LC/min and WOBPHYS/min ranged from 3 to 12 J/min and there was an excellent relationship between WOBANN,LC/breath and WOBPHYS/breath, r = 0.93, r(2) = 0.86 (p < 0.01). An ANN combined with a facemask LC algorithm provides noninvasive and valid estimates of work of breathing during noninvasive PS. WOBANN,LC/min, automatically and continuously estimated, may be useful for assessing inspiratory muscle loads and guiding noninvasive PS settings as in a decision support system to appropriately unload inspiratory muscles. PMID:26070542

  9. Intraoperative mechanical ventilation strategies for one-lung ventilation.

    PubMed

    Şentürk, Mert; Slinger, Peter; Cohen, Edmond

    2015-09-01

    One-lung ventilation (OLV) has two major challenges: oxygenation and lung protection. The former is mainly because the ventilation of one lung is stopped while the perfusion continues; the latter is mainly because the whole ventilation is applied to only one lung. Recommendations for maintaining the oxygenation and methods of lung protection can contradict each other (such as high vs. low inspiratory oxygen fraction (FiO2), high vs. low tidal volume (TV), etc.). In light of the (very few) randomized clinical trials, this review focuses on a recent strategy for OLV, which includes a possible decrease in FiO2, lower TVs, positive end-expiratory pressure (PEEP) to the dependent lung, continuous positive airway pressure (CPAP) to the non-dependent lung and recruitment manoeuvres. Other applications such as anaesthetic choice and fluid management can affect the success of ventilatory strategy; new developments have changed the classical approach in this respect. PMID:26643100

  10. Segmental hemodynamics during partial liquid ventilation in isolated rat lungs

    PubMed Central

    Ko, Angela C.; Hirsh, Emily; Wong, Andrew C.; Moore, Timothy M.; Taylor, Aubrey E.; Hirschl, Ronald B.; Younger, John G.

    2011-01-01

    Partial liquid ventilation (PLV) is a means of ventilatory support in which gas ventilation is carried out in a lung partially filled with a perfluorocarbon liquid capable of supporting gas exchange. Recently, this technique has been proposed as an adjunctive therapy for cardiac arrest, during which PLV with cold perfluorocarbons might rapidly cool the intrathoracic contents and promote cerebral protective hypothermia while not interfering with gas exchange. A concern during such therapy will be the effect of PLV on pulmonary hemodynamics during very low blood flow conditions. In the current study, segmental (i.e. precapillary, capillary, and postcapillary) hemodynamics were studied in the rat lung using a standard isolated lung perfusion system at a flow rate of 6 ml/min ( ~5% normal cardiac output). Lungs received either gas ventilation or 5 or 10 ml/kg PLV. Segmental pressures and vascular resistances were determined, as was transcapillary fluid flux. The relationship between individual hemodynamic parameters and PLV dose was examined using linear regression, with n = 5 in each study group. PLV at both the 5 and 10 ml/kg dose produced no detectable changes in pulmonary blood flow or in transcapillary fluid flux (all R2 values < 0.20). Conclusion: In an isolated perfused lung model of low flow conditions, normal segmental hemodynamic behavior was preserved during liquid ventilation. These data support further investigation of this technique as an adjunct to cardiopulmonary resuscitation. PMID:12668304

  11. A novel target-type low pressure drop bidirectional optoelectronic air flow sensor for infant artificial ventilation: measurement principle and static calibration.

    PubMed

    Saccomandi, Paola; Schena, Emiliano; Silvestri, Sergio

    2011-02-01

    An optoelectronic target-type volumetric air flow-rate transducer for bidirectional measurements is presented. The sensor is composed of a T-shaped target and two nominally identical LED-photodiode couples which are operated in differential mode. The sensitive surfaces of the photodiodes are differentially shadowed by the deflection of the target, which in turn depends on the gas flow-rate. The principle of operation is described in mathematical terms and the design parameters have been optimized in order to obtain the highest sensitivity along with minimal pressure drop and reduced dimensions. The sensor is placed in a 20 mm diameter hose and was tested with air flow-rate in the typical temperature range of mechanical ventilation between 20 and 40 °C. The theoretical model was validated through experiments carried out in the volumetric flow range from -7.0 to +7.0 l min(-1). The nonlinear behavior allows sensitivities equal to 0.6 V l(-1) min for flow rates ranging from -2.0 to +2.0 l min(-1), equal to 2.0 V l(-1) min for flow rates ranging from -3.0 to -2.0 l min(-1) and from +2.0 to +3.0 l min(-1), up to 5.7 V l(-1) min at higher flow rates ranging from -7.0 to -3.0 l min(-1) and from +3.0 to +7.0 l min(-1). The linear range extends from 3.0 to 7.0 l min(-1) with constant sensitivity equal to 5.7 V l(-1) min. The sensor is able to detect a flow-rate equal to 1.0 l min(-1) with a sensitivity of about 400 mV l(-1) min. The differential nature of the output minimizes the influence of the LEDs' power supply variations and allows to obtain a repeatability in the order of 3% of full scale output. The small pressure drop produced by the sensor placed in-line the fluid stream, of about 2.4 Pa at 7 l min(-1), corresponds to a negligible fluid dynamic resistance lower than 0.34 Pa l(-1) min. PMID:21361616

  12. A novel target-type low pressure drop bidirectional optoelectronic air flow sensor for infant artificial ventilation: Measurement principle and static calibration

    NASA Astrophysics Data System (ADS)

    Saccomandi, Paola; Schena, Emiliano; Silvestri, Sergio

    2011-02-01

    An optoelectronic target-type volumetric air flow-rate transducer for bidirectional measurements is presented. The sensor is composed of a T-shaped target and two nominally identical LED-photodiode couples which are operated in differential mode. The sensitive surfaces of the photodiodes are differentially shadowed by the deflection of the target, which in turn depends on the gas flow-rate. The principle of operation is described in mathematical terms and the design parameters have been optimized in order to obtain the highest sensitivity along with minimal pressure drop and reduced dimensions. The sensor is placed in a 20 mm diameter hose and was tested with air flow-rate in the typical temperature range of mechanical ventilation between 20 and 40 °C. The theoretical model was validated through experiments carried out in the volumetric flow range from -7.0 to +7.0 l min-1. The nonlinear behavior allows sensitivities equal to 0.6 V l-1 min for flow rates ranging from -2.0 to +2.0 l min-1, equal to 2.0 V l-1 min for flow rates ranging from -3.0 to -2.0 l min-1 and from +2.0 to +3.0 l min-1, up to 5.7 V l-1 min at higher flow rates ranging from -7.0 to -3.0 l min-1 and from +3.0 to +7.0 l min-1. The linear range extends from 3.0 to 7.0 l min-1 with constant sensitivity equal to 5.7 V l-1 min. The sensor is able to detect a flow-rate equal to 1.0 l min-1 with a sensitivity of about 400 mV l-1 min. The differential nature of the output minimizes the influence of the LEDs' power supply variations and allows to obtain a repeatability in the order of 3% of full scale output. The small pressure drop produced by the sensor placed in-line the fluid stream, of about 2.4 Pa at 7 l min-1, corresponds to a negligible fluid dynamic resistance lower than 0.34 Pa l-1 min.

  13. Pressurized Testing of Solid Oxide Electrolysis Stacks with Advanced Electrode-Supported Cells

    SciTech Connect

    J. E. O'Brien; X. Zhang; G. K. Housley; K. DeWall; L. Moore-McAteer; G. Tao

    2012-06-01

    A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate cell dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation up to 5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this paper.

  14. Summary of human responses to ventilation

    SciTech Connect

    Seppanen, Olli A.; Fisk, William J.

    2004-06-01

    The effects of ventilation on indoor air quality and health is a complex issue. It is known that ventilation is necessary to remove indoor generated pollutants from indoor air or dilute their concentration to acceptable levels. But, as the limit values of all pollutants are not known, the exact determination of required ventilation rates based on pollutant concentrations and associated risks is seldom possible. The selection of ventilation rates has to be based also on epidemiological research (e.g. Seppanen et al., 1999), laboratory and field experiments (e.g. CEN 1996, Wargocki et al., 2002a) and experience (e.g. ECA 2003). Ventilation may also have harmful effects on indoor air quality and climate if not properly designed, installed, maintained and operated as summarized by Seppdnen (2003). Ventilation may bring indoors harmful substances that deteriorate the indoor environment. Ventilation also affects air and moisture flow through the building envelope and may lead to moisture problems that deteriorate the structures of the building. Ventilation changes the pressure differences over the structures of building and may cause or prevent the infiltration of pollutants from structures or adjacent spaces. Ventilation is also in many cases used to control the thermal environment or humidity in buildings. Ventilation can be implemented with various methods which may also affect health (e.g. Seppdnen and Fisk, 2002, Wargocki et al., 2002a). In non residential buildings and hot climates, ventilation is often integrated with air-conditioning which makes the operation of ventilation system more complex. As ventilation is used for many purposes its health effects are also various and complex. This paper summarizes the current knowledge on positive and negative effects of ventilation on health and other human responses. The focus of the paper is on office-type working environment and residential buildings. In the industrial premises the problems of air quality are usually

  15. Initial mechanical ventilator settings for pediatric patients: clinical judgement in selection of tidal volume.

    PubMed

    Kanter, R K; Blatt, S D; Zimmerman, J J

    1987-03-01

    Guidelines for selection of initial mechanical ventilator settings for pediatric patients were evaluated. Protocols specifying tidal volume or peak inspiratory pressure are difficult to apply for infants and children because of leaks at uncuffed endotracheal tubes, compression loss in ventilators, and inaccuracy of settings for intended tidal volume. To avoid these difficulties, the selection of tidal volume was based on subjective clinical observations: visible chest excursion and audible air entry at least simulating normal breathing. In 76 consecutive patients, use of the guidelines resulted in satisfactory PaCO2 for 97% and PaO2 for 89% of infants and children with a wide variety of respiratory disorders. Adequacy of gas exchange was not related to the patient's age, type of ventilator, tightness of fit of the endotracheal tube, or presence of spontaneous breathing. These results support a simple, versatile method of teaching selection of initial mechanical ventilator settings, relying on clinical judgment for regulation of tidal volume. PMID:3470010

  16. Pressure Support in Galaxy Disks: Impact on Rotation Curves and Dark Matter Density Profiles

    NASA Astrophysics Data System (ADS)

    Dalcanton, Julianne J.; Stilp, Adrienne M.

    2010-09-01

    Rotation curves constrain a galaxy's underlying mass density profile, under the assumption that the observed rotation produces a centripetal force that exactly balances the inward force of gravity. However, most rotation curves are measured using emission lines from gas, which can experience additional forces due to pressure. In realistic galaxy disks, the gas pressure declines with radius, providing additional radial support to the disk. The measured tangential rotation speed will therefore tend to lag the true circular velocity of a test particle. The gas pressure is dominated by turbulence, and we evaluate its likely amplitude from recent estimates of the gas velocity dispersion and surface density. We show that where the amplitude of the rotation curve is comparable to the characteristic velocities of the interstellar turbulence, pressure support may lead to underestimates of the mass density of the underlying dark matter halo and the inner slope of its density profile. These effects may be significant for galaxies with rotation speeds lsim75 km s-1 but are unlikely to be significant in higher-mass galaxies. We find that pressure support can be sustained over long timescales, because any reduction in support due to the conversion of gas into stars is compensated for by an inward flow of gas. However, we point to many uncertainties in assessing the importance of pressure support in real or simulated galaxies. Thus, while pressure support may help to alleviate possible tensions between rotation curve observations and ΛCDM on kiloparsec scales, it should not be viewed as a definitive solution at this time.

  17. PRESSURE SUPPORT IN GALAXY DISKS: IMPACT ON ROTATION CURVES AND DARK MATTER DENSITY PROFILES

    SciTech Connect

    Dalcanton, Julianne J.; Stilp, Adrienne M. E-mail: adrienne@astro.washington.ed

    2010-09-20

    Rotation curves constrain a galaxy's underlying mass density profile, under the assumption that the observed rotation produces a centripetal force that exactly balances the inward force of gravity. However, most rotation curves are measured using emission lines from gas, which can experience additional forces due to pressure. In realistic galaxy disks, the gas pressure declines with radius, providing additional radial support to the disk. The measured tangential rotation speed will therefore tend to lag the true circular velocity of a test particle. The gas pressure is dominated by turbulence, and we evaluate its likely amplitude from recent estimates of the gas velocity dispersion and surface density. We show that where the amplitude of the rotation curve is comparable to the characteristic velocities of the interstellar turbulence, pressure support may lead to underestimates of the mass density of the underlying dark matter halo and the inner slope of its density profile. These effects may be significant for galaxies with rotation speeds {approx}<75 km s{sup -1} but are unlikely to be significant in higher-mass galaxies. We find that pressure support can be sustained over long timescales, because any reduction in support due to the conversion of gas into stars is compensated for by an inward flow of gas. However, we point to many uncertainties in assessing the importance of pressure support in real or simulated galaxies. Thus, while pressure support may help to alleviate possible tensions between rotation curve observations and {Lambda}CDM on kiloparsec scales, it should not be viewed as a definitive solution at this time.

  18. Ultrasonic Nondestructive Evaluation of PRSEUS Pressure Cube Article in Support of Load Test to Failure

    NASA Technical Reports Server (NTRS)

    Johnston, Patrick H.

    2013-01-01

    The PRSEUS Pressure Cube Test was a joint development effort between the Boeing Company and NASA Langley Research Center, sponsored in part by the Environmentally Responsible Aviation Project and Boeing internal R&D. This Technical Memorandum presents the results of ultrasonic inspections in support of the PRSEUS Pressure Cube Test, and is a companion document with the NASA test report and a report on the acoustic emission measurements made during the test.

  19. Nanofiber supported thin-film composite membrane for pressure-retarded osmosis.

    PubMed

    Bui, Nhu-Ngoc; McCutcheon, Jeffrey R

    2014-04-01

    Sustainable energy can be harnessed from fluids of differing salinity using a process known as pressure-retarded osmosis (PRO). We address one of the critical challenges of advance PRO by introducing a novel electrospun nanofiber-supported thin-film composite PRO membrane platform. The support was tiered with layers of nanofibers of different diameters to better withstand hydraulic pressure. The membranes successfully withstood an applied hydraulic pressure of 11.5 bar and exhibited performance that would produce an equivalent peak power density near 8.0 W/m(2) under real conditions (using 0.5 M NaCl and deionized water as the draw and feed solutions, respectively). This result shows the immense promise of nanofiber supported thin-film composite membranes for use in PRO. PMID:24387600

  20. History of Mechanical Ventilation. From Vesalius to Ventilator-induced Lung Injury.

    PubMed

    Slutsky, Arthur S

    2015-05-15

    Mechanical ventilation is a life-saving therapy that catalyzed the development of modern intensive care units. The origins of modern mechanical ventilation can be traced back about five centuries to the seminal work of Andreas Vesalius. This article is a short history of mechanical ventilation, tracing its origins over the centuries to the present day. One of the great advances in ventilatory support over the past few decades has been the development of lung-protective ventilatory strategies, based on our understanding of the iatrogenic consequences of mechanical ventilation such as ventilator-induced lung injury. These strategies have markedly improved clinical outcomes in patients with respiratory failure. PMID:25844759

  1. The interplay of parental support, parental pressure and test anxiety--Gender differences in adolescents.

    PubMed

    Ringeisen, Tobias; Raufelder, Diana

    2015-12-01

    This study examined gender-specific relationships between adolescents' perceptions of school-related support/pressure from their parents and test anxiety. A sample of German students (N = 845; Mage = 15.32; SD = .49) completed questionnaires that measured their perceived parental support/pressure (for mother and father separately) as well as the four main components of test anxiety (worry, interference, lack of confidence, and emotionality). Gender-specific relations were identified using multigroup structural equation modeling: For girls, perceived maternal pressure was positively associated with emotionality and interference; for boys, perceived father pressure and father support were positively associated with interference and worry, respectively. For both genders, perceived mother pressure and support were related to lack of confidence. Our findings suggest that adolescents' perceptions of maternal attitudes are associated with students' self-confidence irrespective of the child's gender, whereas the remaining facets of test anxiety follow same-sex trajectories between perceived parental attitudes and adolescents' test anxiety. PMID:26378971

  2. Effectiveness of Synchronized Noninvasive Ventilation to Prevent Intubation in Preterm Infants

    PubMed Central

    Ramos-Navarro, Cristina; Sanchez-Luna, Manuel; Sanz-López, Ester; Maderuelo-Rodriguez, Elena; Zamora-Flores, Elena

    2016-01-01

    Background  Noninvasive ventilation is being increasingly used on preterm infants to reduce ventilator lung injury and bronchopulmonary dysplasia. The aim of this study was to evaluate the effectiveness of synchronized nasal intermittent positive pressure ventilation (SNIPPV) to prevent intubation in premature infants. Methods  Prospective observational study of SNIPPV use on preterm infants of less than 32 weeks' gestation. All patients were managed using a prospective protocol intended to reduce invasive mechanical ventilation (iMV) use. Previous respiratory status, as well as respiratory outcomes and possible secondary side effects were analyzed. Results  SNIPPV was used on 78 patients: electively to support extubation on 25 ventilator-dependent patients and as a rescue therapy after nasal continuous positive airway pressure failure on 53 patients. For 92% of patients in the elective group and 66% in the rescue group, iMV was avoided over the following 72 hours. No adverse effects were detected, and all patients were in a stable condition even if intubation was eventually needed. Conclusions  The application of SNIPPV in place of or to remove mechanical ventilation avoids intubation in 74.4% of preterm infants with respiratory failure. No adverse effects were detected. PMID:27500013

  3. A pressure distribution measurement system for supporting areas of wheelchair users.

    PubMed

    Arias, Sandra; Cardiel, Eladio; Garay, Laura; Tovar, Blanca; Pla, Michele; Rogeli, Pablo

    2013-01-01

    Pressure ulcers are skin injuries caused by long term exposition to high pressures on support points that interrupt blood circulation reducing the transport of oxygen and nutrients to the cells. They mainly affect people with poor mobility that stay in seating position for long periods of time. In spite of the diversity of commercial prototypes of cushions, ulcers caused by pressure are still a problem for wheelchair users. This work describes the design of a measurement system of pressure distribution in sedentary position. The aim of the system is to record the pressure concentration in order to obtain specific information about the supporting areas, and with these data used as feedback, eventually to determine an efficient random stimulation sequence to provide, in the future, a system to prevent these referred injuries. The proposed system consists of a 12 air-cell division cushion. Each cell has a pressure sensor and an input for electro valves to inflate and deflate. The recording and control of the valves is carried out through a graphical interface designed in LabVIEW®. A calibration procedure for the designed cushion was made by comparing the greatest load values pressure with a commercial platform, similar results were obtained. PMID:24110796

  4. Impact of Ventilatory Modes on the Breathing Variability in Mechanically Ventilated Infants

    PubMed Central

    Baudin, Florent; Wu, Hau-Tieng; Bordessoule, Alice; Beck, Jennifer; Jouvet, Philippe; Frasch, Martin G.; Emeriaud, Guillaume

    2014-01-01

    Objectives: Reduction of breathing variability is associated with adverse outcome. During mechanical ventilation, the variability of ventilatory pressure is dependent on the ventilatory mode. During neurally adjusted ventilatory assist (NAVA), the support is proportional to electrical activity of the diaphragm (EAdi), which reflects the respiratory center output. The variability of EAdi is, therefore, translated into a similar variability in pressures. Contrastingly, conventional ventilatory modes deliver less variable pressures. The impact of the mode on the patient’s own respiratory drive is less clear. This study aims to compare the impact of NAVA, pressure-controlled ventilation (PCV), and pressure support ventilation (PSV) on the respiratory drive patterns in infants. We hypothesized that on NAVA, EAdi variability resembles most of the endogenous respiratory drive pattern seen in a control group. Methods: Electrical activity of the diaphragm was continuously recorded in 10 infants ventilated successively on NAVA (5 h), PCV (30 min), and PSV (30 min). During the last 10 min of each period, the EAdi variability pattern was assessed using non-rhythmic to rhythmic (NRR) index. These variability profiles were compared to the pattern of a control group of 11 spontaneously breathing and non-intubated infants. Results: In control infants, NRR was higher as compared to mechanically ventilated infants (p < 0.001), and NRR pattern was relatively stable over time. While the temporal stability of NRR was similar in NAVA and controls, the NRR profile was less stable during PCV. PSV exhibited an intermediary pattern. Perspectives: Mechanical ventilation impacts the breathing variability in infants. NAVA produces EAdi pattern resembling most that of control infants. NRR can be used to characterize respiratory variability in infants. Larger prospective studies are necessary to understand the differential impact of the ventilatory modes on the cardio

  5. New strategies for mechanical ventilation. Lung protective ventilation.

    PubMed

    Wilmoth, D

    1999-12-01

    Although research is ongoing, and there are no definitive data to mandate the final answer to the question of which ventilation strategies result in the most optimal outcomes, the consensus of clinicians today suggests that we limit FIO2 to nontoxic levels, limit ventilating pressures and volumes, and use PEEP levels adequate to recruit alveoli and prevent tidal collapse. The critical care nurse must remain vigilant in his or her review of current literature to maintain knowledge of the current recommendations for optimal MV strategies. PMID:10855109

  6. Hydrostatic Hyperbaric Chamber Ventilation System

    NASA Technical Reports Server (NTRS)

    Sargusingh, Miriam M.

    2011-01-01

    The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications, including the treatment of medical conditions. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy available in the developing world for the treatment of a variety of medical conditions. Specifically, hyperbaric oxygen therapy is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. Hyperbaric oxygen therapy is simply too expensive and too dangerous to implement in the developing world using standard equipment. The hydrostatic hyperbaric chamber technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system that will provide controlled pressurization of the system, and provide adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the

  7. Hydrostatic Hyperbaric Chamber Ventilation System

    NASA Technical Reports Server (NTRS)

    Sarguisingh, Miriam J.

    2012-01-01

    The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy (HBOT) available in the developing world for the treatment of a variety of medical conditions. Specifically, HBOT is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. HBOT is simply too expensive and too dangerous to implement in the developing world using standard equipment. The HHC technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system to provide controlled pressurization and adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware

  8. [ASSESSMENT OF PULMONARY VENTILATION FUNCTION AT INTENSIVE CARE UNIT PATIENTS].

    PubMed

    Mustafin, R; Bakirov, A

    2015-09-01

    The article presents the functional characteristics of lung tissue in reanimation profile patients with different pathologies with forced ventilation and auxiliary support on the background. The aim of this study was to analyze the dynamics properties of lung tissue in intensive care unit patients with symptoms of severe violations of restrictive lung tissue being on ventilatory support. Results were subjected to analysis of acid-base status and dynamics of the main indicators of the biomechanical properties of the lung in 32 patients with severe concomitant injury (n=21), acute bilateral community-acquired pneumonia (n=7), septic shock (n=4) during the entire period of the respiratory "prosthetics "(before and after the beginning of mechanical ventilation). Using during ventilatory support of patients with initial symptoms of the syndrome of acute lung damage and reduced lung function restrictive positive end-expiratory pressure of 6-10 cm of water column when the conventional (1:2; 1:2.5 at p≤0.05) and invert (2:1 at p≤0,1) ratio inhale/exhale, relatively low tidal volume (6-8 ml/kg) allows increase the compliance of the lung tissue to 11-29%. Increased expiratory time constant has a direct correlation with the value of airway resistance was due not only to the maintenance of optimal parameters for MVV (mechanical voluntary ventilation), but regular lavage of the tracheobronchial tree, which allows to maintain patency of the lower respiratory tract. The main areas during mechanical ventilation of lungs in patients with a sharp decline in restrictive lung function (ARDS, pneumonia), regardless of the reason it was summoned, optimal value is the observance of the positive end-expiratory pressure, the ratio of inhale/exhale (depending on the degree of hypoxemia), to maintain sufficient blood oxygen saturation and partial pressure of oxygen in the blood plasma. PMID:26355312

  9. Too Little Oxygen: Ventilation, Prone Positioning, and Extracorporeal Membrane Oxygenation for Severe Hypoxemia.

    PubMed

    Park, Pauline K

    2016-02-01

    Severe hypoxemia is associated with untoward outcomes in acute respiratory distress syndrome patients. Nevertheless, in and of itself, correction of hypoxemia is not an adequate surrogate outcome for mortality and clear evidence-based targets for correction of hypoxemia remain to be determined. At present, clinical management is directed toward achieving sufficient oxygenation while minimizing toxicity of ventilator-induced lung injury. The gold standard remains lung-protective mechanical ventilation, using lower-tidal volumes and pressure-limited ventilator titration. Notable progress in care includes further refinements in mechanical ventilation, consideration of salutatory effects of early prone positioning and neuromuscular blockade, and exploration of adjunctive extrapulmonary support with extracorporeal membrane oxygenation. This review focuses on three specific aspects: the evolving trend toward open lung ventilation, tempered by the recent cautionary experience with high-frequency oscillation ventilation; the evolution of prone positioning as a treatment for the most hypoxemic patients; and the continued future promise of extracorporeal support as a true rescue therapy. PMID:26820269

  10. Mechanical ventilation for severe asthma.

    PubMed

    Leatherman, James

    2015-06-01

    Acute exacerbations of asthma can lead to respiratory failure requiring ventilatory assistance. Noninvasive ventilation may prevent the need for endotracheal intubation in selected patients. For patients who are intubated and undergo mechanical ventilation, a strategy that prioritizes avoidance of ventilator-related complications over correction of hypercapnia was first proposed 30 years ago and has become the preferred approach. Excessive pulmonary hyperinflation is a major cause of hypotension and barotrauma. An appreciation of the key determinants of hyperinflation is essential to rational ventilator management. Standard therapy for patients with asthma undergoing mechanical ventilation consists of inhaled bronchodilators, corticosteroids, and drugs used to facilitate controlled hypoventilation. Nonconventional interventions such as heliox, general anesthesia, bronchoscopy, and extracorporeal life support have also been advocated for patients with fulminant asthma but are rarely necessary. Immediate mortality for patients who are mechanically ventilated for acute severe asthma is very low and is often associated with out-of-hospital cardiorespiratory arrest before intubation. However, patients who have been intubated for severe asthma are at increased risk for death from subsequent exacerbations and must be managed accordingly in the outpatient setting. PMID:26033128

  11. Space Station Environment Control and Life Support System Pressure Control Pump Assembly Modeling and Analysis

    NASA Technical Reports Server (NTRS)

    Schunk, R. Gregory

    2002-01-01

    This paper presents the Modeling and Analysis of the Space Station Environment Control and Life Support System Pressure Control Pump Assembly (PCPA). The contents include: 1) Integrated PCPA/Manifold Analyses; 2) Manifold Performance Analysis; 3) PCPA Motor Heat Leak Study; and 4) Future Plans. This paper is presented in viewgraph form.

  12. Reduced Pressure Atmosphere Impacts on Life Support and Internal Thermal Systems

    NASA Technical Reports Server (NTRS)

    Anderson, Molly

    2006-01-01

    Selecting the appropriate atmosphere for a spacecraft and mission is a complicated problem. NASA has previously used atmospheres from Earth normal composition and pressure to pure oxygen at low pressures. Future exploration missions will likely strike a compromise somewhere between the two, trying to balance operation impacts on EVA, safety concerns for flammability and health risks, life science and physiology questions, and other issues. Life support systems and internal thermal control systems are areas that will have to respond to changes in the atmospheric composition and pressure away from the Earthlike conditions currently used on the International Space Station. This paper examines life support and internal thermal control technologies currently in use or in development to find what impacts in design, efficiency and performance, or feasibility might be expected. Understanding these changes should be helpful in producing better results during future trade studies or mission analyses.

  13. The Stress-Buffering Effects of Functional Social Support on Ambulatory Blood Pressure

    PubMed Central

    Bowen, Kimberly S.; Uchino, Bert N.; Birmingham, Wendy; Carlisle, McKenzie; Smith, Timothy W.; Light, Kathleen C.

    2014-01-01

    Objective Social support is a reliable predictor of cardiovascular health. According to the buffering hypothesis, stress is one mechanism by which support is able to affect physiological processes. However, most of the experimental evidence for the hypothesis comes from laboratory studies. Ambulatory blood pressure protocols examine participants in their natural environment, where they are more likely to encounter personally relevant real-world stressors. Furthermore, prior work shows that examining support by its specific functional components reveals additional independent links to health. Methods The current study aimed to examine the stress-buffering effects of functional social support on ABP. 188 participants completed a one day ABP assessment along with measures of functional social support and both global perceived stress and momentary stress at time of reading. Results Results indicated main effects for both stress measures. Global support, emotional, tangible, and informational support only moderated the effects of momentary stress, but not global stress, in predicting ABP. Informational support was the most consistent stress-buffering predictor of ABP, predicting both ambulatory SBP and DBP. Conclusions The predicted values in ABP for informational support achieved health-relevant differences, emphasizing the value of examining functional support beyond global support alone. PMID:24245843

  14. Home monitoring of daytime mouthpiece ventilation effectiveness in patients with neuromuscular disease.

    PubMed

    Nardi, Julie; Leroux, Karl; Orlikowski, David; Prigent, Hélène; Lofaso, Frédéric

    2016-02-01

    Mouthpiece ventilation (MPV) allows patients with neuromuscular disease to receive daytime support from a portable ventilator, which they can disconnect at will, for example, for speaking, eating, swallowing, and coughing. However, MPV carries a risk of underventilation. Our purpose here was to evaluate the effectiveness of daytime MPV under real-life conditions. Eight wheelchair-bound patients who used MPV underwent daytime polygraphy at home with recordings of airflow, mouthpiece pressure, thoracic and abdominal movements, peripheral capillary oxygen saturation (SpO2), and transcutaneous partial pressure of carbon dioxide (PtcCO2). Times and durations of tasks and activities were recorded. The Apnea-Hypopnea Index (AHI) was computed. Patient-ventilator disconnections ≥3 minutes and episodes of hypoventilation defined as PtcCO2>45 mmHg were counted. Patient-ventilator asynchrony events were analyzed. The AHI was >5 hour(-1) in two patients. Another patient experienced unexplained 3% drops in arterial oxygen saturations at a frequency of 70 hour(-1). Patient-ventilator disconnections ≥3 minutes occurred in seven of eight patients and were consistently associated with decreases in SpO2 and ≥5-mmHg increases in PtcCO2; PtcCO2 rose above 45 mmHg in two patients during these disconnections. The most common type of patient-ventilator asynchrony was ineffective effort. This study confirms that MPV can be effective as long as the patient remains connected to the mouthpiece. However, transient arterial oxygen desaturation and hypercapnia due to disconnection from the ventilator may occur, without inducing unpleasant sensations in the patients. Therefore, an external warning system based on a minimal acceptable value of minute ventilation would probably be useful. PMID:26703922

  15. Intermittent-flow expiratory ventilation (IFEV): delivery technique and principles of action--a preliminary communication.

    PubMed

    Gilbert, J; Larsson, A; Smith, R B; Bunegin, L

    1991-01-01

    The ventilator support utilized in acute respiratory failure can exacerbate an underlying lung injury. Various ventilation techniques have been introduced to prevent such damage by limiting tidal volume and inflation pressure, ensuring uniform expansion of the lung, and stabilizing lung volume during expiration. Acceptance of such methods has been limited. Intermittent-flow expiratory ventilation (IFEV) is the latest development in limited-excursion pulmonary ventilation. The method involves the delivery of fresh gas to the respiratory tree during expiration, thereby flushing out the anatomic deadspace and ensuring that the gas initially delivered to the alveolus with the succeeding inspiration is able to participate in gas exchange. By eliminating end-tidal gas in the conducting air passages, series deadspace is functionally reduced, permitting lowering of tidal volume and airway pressures without a corresponding reduction in CO2 removal. This effect may benefit patients who have acute lung injury by permitting ventilator settings with lower tidal volumes and peak airway pressures. The technique of IFEV delivery, a successful clinical application, and possible ways to improve IFEV efficiency are discussed. PMID:1777767

  16. Incidence of Parental Support and Pressure on Their Children's Motivational Processes towards Sport Practice Regarding Gender.

    PubMed

    Amado, Diana; Sánchez-Oliva, David; González-Ponce, Inmaculada; Pulido-González, Juan José; Sánchez-Miguel, Pedro Antonio

    2015-01-01

    Grounded in Self-Determination Theory, structural equation modeling (SEM) with the aim of examining how parental support/pressure could influence their children´s motivational processes in sport was conducted, as well as the models´ differences in operability regarding gender. The sample size was 321 children ranging in age from 10 to 16 years old who were athletes from Extremadura, and 321 parents (included only the father or mother more involved with the sport of his or her child). 175 participants were male and 146 were female from individual (n = 130), and team sports (n=191). A questionnaire was conducted to assess parental perception of support/pressure and another questionnaire was conducted to measure satisfaction of basic psychological needs, type of motivation and enjoyment/boredom showed by their children towards sport practice. Results revealed that parental pressure negatively predicted satisfaction of the basic psychological needs. It also emerged as a strong positive predictor of intrinsic motivation and negative predictor of amotivation. Moreover, intrinsic motivation emerged as positive predictor of enjoyment and a negative predictor of boredom, whereas amotivation positively predicted boredom and negatively predicted enjoyment. Furthermore, results showed there were mean differences by gender: male athletes perceived greater parental pressure. Hence, it is necessary to decrease parental pressure towards their children in sport, with the aim of making them more motivated and enjoy, promoting positive consequences. PMID:26039062

  17. Meclofenamate increases ventilation in lambs.

    PubMed

    Guerra, F A; Savich, R D; Clyman, R I; Kitterman, J A

    1989-01-01

    To investigate the effects of the prostaglandin synthetase inhibitor, meclofenamate, on postnatal ventilation, we studied 11 unanaesthetised, spontaneously-breathing lambs at an average age of 7.9 +/- 1.1 days (SEM; range 5-14 days) and an average weight of 4.9 +/- 0.5 kg (range 3.0-7.0 kg). After a 30-min control period we infused 4.23 mg/kg meclofenamate over 10 min and then gave 0.23 mg/h per kg for the remainder of the 4 h. Ventilation increased progressively from a control value of 515 +/- 72 ml/min per kg to a maximum of 753 +/- 100 ml/min per kg after 3h of infusion (P less than 0.05) due to an increased breathing rate; the effects were similar during both high- and low-voltage electrocortical activity. There were no significant changes in tidal volume, heart rate, blood pressure, arterial pH or PaCO2, the increased ventilation resulted from either an increase in dead space ventilation or an increase in CO2 production. This study indicates that meclofenamate causes an increase in ventilation in lambs but no changes in pH of PaCO2. The mechanism and site of action remain to be defined. PMID:2507622

  18. International Space Station Environmental Control and Life Support System Acceptance Testing for the Pressurized Mating Adapters

    NASA Technical Reports Server (NTRS)

    Williams, David E.

    2008-01-01

    The International Space Station (ISS) Pressurized Mating Adapters (PMAs) Environmental Control and Life Support (ECLS) System is comprised of three subsystems: Atmosphere Control and Supply (ACS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). PMAs 1 and 2 flew to ISS on Flight 2A and Pressurized Mating Adapter (PMA) 3 flew to ISS on Flight 3A. This paper provides a summary of the PMAs ECLS design and a detailed discussion of the ISS ECLS Acceptance Testing methodologies utilized for the PMAs.

  19. Instabilities of bellows: Dependence on internal pressure, end supports, and interactions in accelerator magnet systems

    SciTech Connect

    Shutt, R.P.; Rehak, M.L.

    1990-01-01

    For superconducting magnets, one needs many bellows for connection of various helium cooling transfer lines in addition to beam tube bellows. There could be approximately 10,000 magnet interconnection bellows in the SSC exposed to an internal pressure. When axially compressed or internally pressurized, bellows can become unstable, leading to gross distortion or complete failure. If several bellows are contained in an assembly, failure modes might interact. If designed properly, large bellows can be a very feasible possibility for connecting the large tubular shells that support the magnet iron yokes and superconducting coils and contain supercritical helium for magnet cooling. We present here (1) a spring-supported bellows model, in order to develop necessary design features for bellows and end supports so that instabilities will not occur in the bellows pressure operating region, including some margin, (2) a model of three superconducting accelerator magnets connected by two large bellows, in order to ascertain that support requirements are satisfied and in order to study interaction effects between the two bellows. Reliability of bellows for our application will be stressed. 3 refs., 4 figs.

  20. PaCO2 in Surfactant, Positive Pressure, and Oxygenation Randomized Trial (SUPPORT)

    PubMed Central

    Ambalavanan, Namasivayam; Carlo, Waldemar A.; Wrage, Lisa A.; Das, Abhik; Laughon, Matthew; Cotten, C. Michael; Kennedy, Kathleen A.; Laptook, Abbot R.; Shankaran, Seetha; Walsh, Michele C.; Higgins, Rosemary D.

    2015-01-01

    Objective To determine the association of PaCO2 with severe intraventricular hemorrhage (sIVH), bronchopulmonary dysplasia (BPD), and neurodevelopmental impairment (NDI) at 18–22 months in premature infants. Design Secondary exploratory data analysis of SUPPORT. Setting Multiple referral NICUs. Patients 1316 infants 24 0/7 to 27 6/7 weeks gestation randomized to different oxygenation (SpO2 target 85–89% vs 91–95%) and ventilation strategies. Main Outcome Measures Blood gases from postnatal days 0–14 were analyzed. Five PaCO2 variables were defined: minimum [Min], maximum [Max], standard deviation, average (time-weighted), and a 4 level categorical variable (hypercapnic [highest quartile of Max PaCO2], hypocapnic [lowest quartile of Min PaCO2], fluctuators [both hypercapnia and hypocapnia], and normocapnic [middle two quartiles of Max and Min PaCO2]). PaCO2 variables were compared for infants with and without sIVH, BPD, and NDI (+/− death). Multivariable logistic regression models were developed for adjusted results. Results sIVH, BPD, and NDI (+/− death) were associated with hypercapnic infants and fluctuators. Association of Max PaCO2 and outcomes persisted after adjustment (Per 10 mmHg increase: sIVH/death: OR 1.27 [1.13–1.41]; BPD/death: OR 1.27 [1.12–1.44]; NDI/death: OR 1.23 [1.10–1.38], Death: OR 1.27 [1.12–1.44], all p <0.001). No interaction was found between PaCO2 category and SpO2 treatment group for sIVH/death, NDI/death, or death. Max PaCO2 was positively correlated with maximum FiO2 (rs0.55, p<0.0001) & ventilator days (rs0.61, p<0.0001). Conclusions Higher PaCO2 was an independent predictor of sIVH/death, BPD/death, and NDI/death. Further trials are needed to evaluate optimal PaCO2 targets for high risk infants. PMID:25425651

  1. Design of high pressure oxygen filter for extravehicular activity life support system, volume 1

    NASA Technical Reports Server (NTRS)

    Wilson, B. A.

    1977-01-01

    The experience of the National Aeronautics and Space Administration (NASA) with extravehicular activity life support emergency oxygen supply subsystems has shown a large number of problems associated with particulate contamination. These problems have resulted in failures of high pressure oxygen component sealing surfaces. A high pressure oxygen filter was designed which would (a) control the particulate contamination level in the oxygen system to a five-micron glass bead rating, ten-micron absolute condition (b) withstand the dynamic shock condition resulting from the sudden opening of 8000 psi oxygen system shutoff valve. Results of the following program tasks are reported: (1) contaminant source identification tests, (2) dynamic system tests, (3) high pressure oxygen filter concept evaluation, (4) design, (5) fabrication, (6) test, and (7) application demonstration.

  2. Effect of a suspension seat support chair on the trunk flexion angle and gluteal pressure during computer work

    PubMed Central

    Yoo, Won-gyu

    2015-01-01

    [Purpose] We assessed the effects of a suspension seat support chair on the trunk flexion angle and gluteal pressure during computer work. [Subjects] Ten males were recruited. [Methods] The suspension seat support was developed to prevent abnormal gluteal pressure and a slumped sitting posture during computer work. The gluteal pressure was measured with a TekScan system and the trunk flexion angle was measured with a video camera, to compare the differences between a general chair and the suspension seat support. [Results] The gluteal peak pressures were decreased significantly in the suspension seat support versus the general chair. The trunk flexion angle was also decreased significantly in the suspension seat support compared with the general chair. [Conclusions] This study suggests that the suspension seat support chair contributes to preventing abnormal gluteal pressure and a slumped sitting posture. PMID:26504341

  3. Intratracheal pulmonary ventilation and congenital diaphragmatic hernia: a report of two cases.

    PubMed

    Wilson, J M; Thompson, J R; Schnitzer, J J; Bower, L K; Lillehei, C W; Perlman, N D; Kolobow, T

    1993-03-01

    Previous studies from our institution have shown that neonates with congenital diaphragmatic hernia (CDH), whose best postductal PaO2 (BPDPO2) was less than 100 mm Hg while on maximal conventional mechanical ventilation (CMV), had a mortality exceeding 90%. When combined with extracorporeal membrane oxygenation (ECMO), the mortality rose to 100% in those infants who developed hypercarbia following decannulation. Historically, those patients have required increasing ventilator support, leading to iatrogenic lung damage, and eventual death. Intratracheal pulmonary ventilation (ITPV) using the reverse thrust catheter (RTC) developed by Kolobow incorporates a continuous flow of humidified gas through a reverse Venturi catheter positioned at the distal end of the endotracheal tube. In animal studies, ITPV was shown to result in a reduced physiological dead-space (VD), to facilitate expiration, and to enhance CO2 elimination. In our current study, we have applied ITPV in two neonates with CDH who could not be weaned from ECMO because of uncontrollable hypercapnia, and who met above criteria for 100% mortality. In both cases, ITPV restored normal PaCO2 at low peak inspiratory pressure (PIP) with a substantial decrease in VD. We believe ITPV is suited to ventilating newborns with CDH in whom barotrauma is known to be common. Beyond its present use, ITPV may be useful to ventilate children with other forms of respiratory failure, and should be so considered along with other now available methods of mechanical pulmonary ventilation. PMID:8468666

  4. The user--friendliness of protective support surfaces in prevention of pressure sores.

    PubMed

    Conine, T A; Choi, A K; Lim, R

    1989-01-01

    Special mattress overlays and seat cushions for the prevention of pressure sores constitute a large portion of the rehabilitation products market. Consumers frequently face economic concerns in choosing among these products. This article summarizes the favorable and unfavorable features of major support surface types: foam, air-filled, flotation, and alternating air. A careful consideration of characteristics, such as fire safety, patient comfort, and ease of transfer and handling, may facilitate selection and result in more satisfied users and caregivers. PMID:2781130

  5. International Space Station Environmental Control and Life Support System: Verification for the Pressurized Mating Adapters

    NASA Technical Reports Server (NTRS)

    Williams, David E.

    2007-01-01

    The International Space Station (ISS) Pressurized Mating Adapters (PMAs) Environmental Control and Life Support (ECLS) System is comprised of three subsystems: Atmosphere Control and Supply (ACS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). PMA 1 and PMA 2 flew to ISS on Flight 2A and PMA 3 flew to ISS on Flight 3A. This paper provides a summary of the PMAs ECLS design and the detailed Element Verification methodologies utilized during the Qualification phase for the PMAs.

  6. Fracture ventilation by surface winds

    NASA Astrophysics Data System (ADS)

    Nachshon, U.; Dragila, M. I.; Weisbrod, N.

    2011-12-01

    Gas exchange between the Earth subsurface and the atmosphere is an important mechanism, affecting hydrological, agricultural and environmental processes. From a hydrological aspect, water vapor transport is the most important process related to Earth-atmosphere gas exchange. In respect to agriculture, gas transport in the upper soil profile is important for soil aeration. From an environmental aspect, emission of volatile radionuclides, such as 3H, 14C and Rd from radioactive waste disposal facilities; volatile organic components from industrial sources and Rn from natural sources, all found in the upper vadose zone, can greatly affect public health when emissions occur in populated areas. Thus, it is vital to better understand gas exchange processes between the Earth's upper crust and atmosphere. Four major mechanisms are known to transfer gases between ground surface and atmosphere: (1) Diffusion; (2) Pressure gradients between ground pores and atmosphere due to changes in barometric pressure; (3) Density-driven gas flow in respond to thermal gradients in the ground; and (4) Winds above the ground surface. Herein, the wind ventilation mechanism is studied. Whereas the wind's impact on ground ventilation was explored in several studies, the physical mechanisms governing this process were hardly quantified or characterized. In this work the physical properties of fracture ventilation due to wind blowing along land surface were explored and quantified. Both field measurements and Hele-Shaw experiments under controlled conditions in the laboratory were used to study this process. It was found that winds in the range of 0.3 m/s result in fracture ventilation down to a depth of 0.2 m. As wind velocity increases, the depth of the ventilation inside the fracture increases respectively, in a linear manner. In addition, the fracture aperture also affects the depth of ventilation, which grows as fracture aperture increases. For the maximal examined aperture of 2 cm and wind

  7. An air bearing fan for EVA suit ventilation

    NASA Technical Reports Server (NTRS)

    Murry, Roger P.

    1990-01-01

    The portable life-support system (PLSS) ventilation requirements are outlined, along with the application of a high-speed axial fan technology for extravehicular-activity (EVA) space-suit ventilation. Focus is placed on a mechanical design employing high-speed gas bearings, permanent magnet rotor, and current-fed chopper/inverter electronics. The operational characteristics of the fan unit and its applicability for use in a pure-oxygen environment are discussed. It delivers a nominal 0.17 cu m/min at 1.24 kPa pressure rise using 13.8 w of input power. It is shown that the overall selection of materials for all major component meets the NASA requirements.

  8. ORION Environmental Control and Life Support Systems Suit Loop and Pressure Control Analysis

    NASA Technical Reports Server (NTRS)

    Eckhardt, Brad; Conger, Bruce; Stambaugh, Imelda C.

    2015-01-01

    Under NASA's ORION Multi-Purpose Crew Vehicle (MPCV) Environmental Control and Life Support System (ECLSS) Project at Johnson Space Center's (JSC), the Crew and Thermal Systems Division has developed performance models of the air system using Thermal Desktop/FloCAD. The Thermal Desktop model includes an Air Revitalization System (ARS Loop), a Suit Loop, a Cabin Loop, and Pressure Control System (PCS) for supplying make-up gas (N2 and O2) to the Cabin and Suit Loop. The ARS and PCS are designed to maintain air quality at acceptable O2, CO2 and humidity levels as well as internal pressures in the vehicle Cabin and during suited operations. This effort required development of a suite of Thermal Desktop Orion ECLSS models to address the need for various simulation capabilities regarding ECLSS performance. An initial highly detailed model of the ARS Loop was developed in order to simulate rapid pressure transients (water hammer effects) within the ARS Loop caused by events such as cycling of the Pressurized Swing Adsorption (PSA) Beds and required high temporal resolution (small time steps) in the model during simulation. A second ECLSS model was developed to simulate events which occur over longer periods of time (over 30 minutes) where O2, CO2 and humidity levels, as well as internal pressures needed to be monitored in the cabin and for suited operations. Stand-alone models of the PCS and the Negative Pressure relief Valve (NPRV) were developed to study thermal effects within the PCS during emergency scenarios (Cabin Leak) and cabin pressurization during vehicle re-entry into Earth's atmosphere. Results from the Orion ECLSS models were used during Orion Delta-PDR (July, 2014) to address Key Design Requirements (KDR's) for Suit Loop operations for multiple mission scenarios.

  9. State of the evidence: mechanical ventilation with PEEP in patients with cardiogenic shock

    PubMed Central

    Wiesen, Jonathan; Ornstein, Moshe; Tonelli, Adriano R; Menon, Venu; Ashton, Rendell W

    2014-01-01

    The need to provide invasive mechanical ventilatory support to patients with myocardial infarction and acute left heart failure is common. Despite the large number of patients requiring mechanical ventilation in this setting, there are remarkably few data addressing the ideal mode of respiratory support in such patients. Although there is near universal acceptance regarding the use of non-invasive positive pressure ventilation in patients with acute pulmonary oedema, there is more concern with invasive positive pressure ventilation owing to its more significant haemodynamic impact. Positive end-expiratory pressure (PEEP) is almost universally applied in mechanically ventilated patients due to benefits in gas exchange, recruitment of alveolar units, counterbalance of hydrostatic forces leading to pulmonary oedema and maintenance of airway patency. The limited available clinical data suggest that a moderate level of PEEP is safe to use in severe left ventricular (LV) dysfunction and cardiogenic shock, and may provide haemodynamic benefits as well in LV failure which exhibits afterload-sensitive physiology. PMID:23539555

  10. Initial synchronized intermittent mandatory ventilation versus assist/control ventilation in treatment of moderate acute respiratory distress syndrome: a prospective randomized controlled trial

    PubMed Central

    Luo, Jian; Wang, Mao-Yun; Liang, Bin-Miao; Yu, He; Jiang, Fa-Ming; Wang, Ting; Shi, Chao-Li; Li, Pei-Jun; Liu, Dan; Wu, Xiao-Ling

    2015-01-01

    Background Assist/control (A/C) ventilation may induce delirium in patients with acute respiratory distress syndrome (ARDS). We conducted a trial to determine whether initial synchronized intermittent mandatory ventilation with pressure support (SIMV + PS) could improve clinical outcomes in these patients. Methods Intubated patients with moderate ARDS were enrolled and we compared SIMV + PS with A/C. Identical sedation, analgesia and ventilation strategies were performed. The co-primary outcomes were early (≤72 h) partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) and incidence of delirium. The secondary outcomes were all-cause in-hospital mortality, dosages of analgesics and sedatives, incidence of patient-ventilator asynchrony, and duration of mechanical ventilation and hospital stay. Results We screened 2,684 patients and 40 patients were enrolled in our study. In SIMV + PS, early (≤72 h) PaO2/FiO2 was greater improved than that at baseline and that in A/C (P<0.05) with lower positive end-expiratory pressure (PEEP) (8.7±3.0 vs. 10.3±3.2, P<0.001) and FiO2 (58%±18% vs. 67%±19%, P<0.001). We found more SIMV + PS success (defined as SIMV + PS successfully applied without switching to A/C) (100.0% vs. 16.7%, P<0.001), less male (46.3% vs. 85.7%, P=0.015) and pulmonary etiology of ARDS (53.8% vs. 92.9%, P=0.015), and lower PEEP (9.1±3.1 vs. 10.3±3.3, P=0.004) and FiO2 (58%±19% vs. 71%±19%, P<0.001) in survival patients. However, there were no significant differences in incidence of delirium and mortality, dosages of analgesics and sedatives, incidence of patient-ventilator asynchrony, duration of mechanical ventilation and hospital stay (P>0.05). Conclusions In patients with moderate ARDS, SIMV + PS can safely and effectively improve oxygenation, but does not decrease mortality, incidence of delirium and patient-ventilator asynchrony, dosages of analgesics and sedatives, and duration of mechanical ventilation and hospital stay

  11. The Role of Internalized Stereotyping, Parental Pressure, and Parental Support on Asian Americans' Choice of College Major

    ERIC Educational Resources Information Center

    Shen, Frances C.

    2015-01-01

    The author explored the relationship between internalized stereotyping, parental pressure, and parental support on major choices among 315 Asian American undergraduate and graduate students. Results indicated that parental support, but not parental pressure, toward certain majors was associated with more stereotypical major choices. In addition,…

  12. Pulmonary perfusion during anesthesia and mechanical ventilation.

    PubMed

    Hedenstierna, G

    2005-06-01

    Cardiac output and the pulmonary perfusion can be affected by anesthesia and by mechanical ventilation. The changes contribute to impeded oxygenation of the blood. The major determinant of perfusion distribution in the lung is the relation between alveolar and pulmonary capillary pressures. Perfusion increases down the lung, due to hydrostatic forces. Since atelectasis is located in dependent lung regions, perfusion of non-ventilated lung parenchyma is common, producing shunt of around 8-10% of cardiac output. In addition, non-gravitational inhomogeneity of perfusion, that can be greater than the gravitational inhomogeneity, adds to impeded oxygenation of blood. Essentially all anaesthetics exert some, although mild, cardiodepressant action with one exception, ketamine. Ketamine may also increase pulmonary artery pressure, whereas other agents have little effect on pulmonary vascular tone. Mechanical ventilation impedes venous return and pushes blood flow downwards to dependent lung regions, and the effect may be striking with higher levels of PEEP. During one-lung anesthesia, there is shunt blood flow both in the non-ventilated and the ventilated lung, and shunt can be much larger in the ventilated lung than thought of. Recruitment manoeuvres shall be directed to the ventilated lung and other physical and pharmacological measures can be taken to manipulate blood flow in one lung anesthesia. PMID:15886595

  13. Solar ventilation and tempering

    NASA Astrophysics Data System (ADS)

    Adámek, Karel; Pavlů, Miloš; Bandouch, Milan

    2014-08-01

    The paper presents basic information about solar panels, designed, realized and used for solar ventilation of rooms. Used method of numerical flow simulation gives good overview about warming and flowing of the air in several kinds of realized panels (window, facade, chimney). Yearlong measurements give a good base for calculations of economic return of invested capital. The operation of the system in transient period (spring, autumn) prolongs the period without classical heating of the room or building, in winter the classical heating is supported. In the summer period the system, furnished with chimney, can exhaust inner warm air together with necessary cooling of the system by gravity circulation, only. System needs not any invoiced energy source; it is supplied entirely by solar energy. Large building systems are supported by classical electric fan respectively.

  14. Influence of lower body pressure support on the walking patterns of healthy children and adults.

    PubMed

    Kurz, Max J; Deffeyes, Joan E; Arpin, David J; Karst, Gregory M; Stuberg, Wayne A

    2012-11-01

    The purpose of this investigation was to evaluate the effect of a lower body positive pressure support system on the joint kinematics and activity of the lower extremity antigravity musculature of adults and children during walking. Adults (age = 25 ± 4 years) and children (age = 13 ± 2 years) walked at a preferred speed and a speed that was based on the Froude number, while 0-80% of their body weight was supported. Electrogoniometers were used to monitor knee and ankle joint kinematics. Surface electromyography was used to quantify the magnitude of the vastus lateralis and gastrocnemius muscle activity. There were three key findings: (1) The lower extremity joint angles and activity of the lower extremity antigravity muscles of children did not differ from those of adults. (2) The magnitude of the changes in the lower extremity joint motion and antigravity muscle activity was dependent upon an interaction between body weight support and walking speed. (3) Lower body positive pressure support resulted in reduced activation of the antigravity musculature, and reduced range of motion of the knee and ankle joints. PMID:22695469

  15. VENTILATION MODEL REPORT

    SciTech Connect

    V. Chipman

    2002-10-31

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses.

  16. Use of Pressure-Redistributing Support Surfaces among Elderly Hip Fracture Patients across the Continuum of Care: Adherence to Pressure Ulcer Prevention Guidelines

    ERIC Educational Resources Information Center

    Baumgarten, Mona; Margolis, David; Orwig, Denise; Hawkes, William; Rich, Shayna; Langenberg, Patricia; Shardell, Michelle; Palmer, Mary H.; McArdle, Patrick; Sterling, Robert; Jones, Patricia S.; Magaziner, Jay

    2010-01-01

    Purpose: To estimate the frequency of use of pressure-redistributing support surfaces (PRSS) among hip fracture patients and to determine whether higher pressure ulcer risk is associated with greater PRSS use. Design and Methods: Patients (n = 658) aged [greater than or equal] 65 years who had surgery for hip fracture were examined by research…

  17. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

  18. Cardiac gated ventilation

    NASA Astrophysics Data System (ADS)

    Hanson, C. William, III; Hoffman, Eric A.

    1995-05-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. We evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50msec scan aperture. Multislice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. We observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a nonfailing model of the heart.

  19. [Mechanical ventilation in chronic ventilatory insufficiency].

    PubMed

    Schucher, B; Magnussen, H

    2007-10-01

    Mechanical ventilation has become an important treatment option in chronic ventilatory failure. There are different diseases which lead to ventilatory failure and to home mechanical ventilation (HMV). A primary loss of in- and expiratory muscle strength is the reason for respiratory deterioration in neuromuscular disease. In most of these diseases ventilatory failure develops because of the progressive character of muscular damage. Initially, ventilatory failure can be found during night-time. In the case of hypercapnia at daytime, life expectancy is strongly reduced, especially in amyotrophic lateral sclerosis and Duchenne muscular dystrophy. HMV leads to a prolongation of life and to an increase in quality of life, if bulbar involvement is not severe. Impressive clinical improvements under HMV have been found in restrictive disorders of the rib cage like kyphoscoliosis or posttuberculosis sequelae, with an increase of quality of life, walking distance and a decrease in pulmonary hypertension. Only few data are published about long-term results of HMV in Obesity Hypoventilation. In terms of retrospective analyses of clinical data HMV seems to improve survival in this population. Some patients only need CPAP treatment, but most patients have to be treated with ventilatory support. The application of HMV in patients with chronic ventilatory failure due to chronic obstructive pulmonary disease (COPD) is growing, but there are controversial results in randomised clinical trials. Analysis of these data suggest better results of HMV in patients with severe hypercapnia, with the application of higher effective ventilatory pressure and a ventilator mode with a significant reduction in the work of breathing. Under such conditions HMV leads to a reduction of hypercapnia, an improvement in sleep quality, walking distance and quality of life, but until now there is no evidence in reduction of mortality in COPD. PMID:17620231

  20. Prediction of pore-water pressure response to rainfall using support vector regression

    NASA Astrophysics Data System (ADS)

    Babangida, Nuraddeen Muhammad; Mustafa, Muhammad Raza Ul; Yusuf, Khamaruzaman Wan; Isa, Mohamed Hasnain

    2016-05-01

    Nonlinear complex behavior of pore-water pressure responses to rainfall was modelled using support vector regression (SVR). Pore-water pressure can rise to disturbing levels that may result in slope failure during or after rainfall. Traditionally, monitoring slope pore-water pressure responses to rainfall is tedious and expensive, in that the slope must be instrumented with necessary monitors. Data on rainfall and corresponding responses of pore-water pressure were collected from such a monitoring program at a slope site in Malaysia and used to develop SVR models to predict pore-water pressure fluctuations. Three models, based on their different input configurations, were developed. SVR optimum meta-parameters were obtained using k-fold cross validation and a grid search. Model type 3 was adjudged the best among the models and was used to predict three other points on the slope. For each point, lag intervals of 30 min, 1 h and 2 h were used to make the predictions. The SVR model predictions were compared with predictions made by an artificial neural network model; overall, the SVR model showed slightly better results. Uncertainty quantification analysis was also performed for further model assessment. The uncertainty components were found to be low and tolerable, with d-factor of 0.14 and 74 % of observed data falling within the 95 % confidence bound. The study demonstrated that the SVR model is effective in providing an accurate and quick means of obtaining pore-water pressure response, which may be vital in systems where response information is urgently needed.

  1. Consequence evaluation of radiation embrittlement of Trojan reactor pressure vessel supports

    SciTech Connect

    Lu, S.C.; Sommer, S.C.; Johnson, G.L. ); Lambert, H.E. )

    1990-10-01

    This report describes a consequence evaluation to address safety concerns raised by the radiation embrittlement of the reactor pressure vessel (RPV) supports for the Trojan nuclear power plant. The study comprises a structural evaluation and an effects evaluation and assumes that all four reactor vessel supports have completely lost the load carrying capability. By demonstrating that the ASME code requirements governing Level D service limits are satisfied, the structural evaluation concludes that the Trojan reactor coolant loop (RCL) piping is capable of transferring loads to the steam generator (SG) supports and the reactor coolant pump (RCP) supports. A subsequent design margins to accommodate additional loads transferred to them through the RCL piping. The effects evaluation, employing a systems analysis approach, investigates initiating events and the reliability of the engineered safeguard systems as the RPV is subject to movements caused by the RPV support failure. The evaluation identifies a number of areas of additional safety concerns, but further investigation of the above safety concerns, however, concludes that a hypothetical failure of the Trojan RPV supports due to radiation embrittlement will not result in consequences of significant safety concerns.

  2. VENTILATION TECHNOLOGY SYSTEMS ANALYSIS

    EPA Science Inventory

    The report gives results of a project to develop a systems analysis of ventilation technology and provide a state-of-the-art assessment of ventilation and indoor air quality (IAQ) research needs. (NOTE: Ventilation technology is defined as the hardware necessary to bring outdoor ...

  3. Axisymmetric, Ventilated Supercavitation in Unsteady, Horizontal Flow

    NASA Astrophysics Data System (ADS)

    Kawakami, Ellison; Lee, Seung-Jae; Arndt, Roger

    2012-11-01

    Drag reduction and/or speed augmentation of marine vehicles by means of supercavitation is a topic of great interest. During the initial launch of a supercavitating vehicle, an artificial supercavity is required until the vehicle can reach conditions at which a natural supercavity can be sustained. Previous studies at Saint Anthony Falls Laboratory (SAFL) focused on the behavior of ventilated supercavities in steady horizontal flows. In open waters, vehicles can encounter unsteady flows, especially when traveling under waves. A study has been carried out at SAFL to investigate the effects of unsteady flow on axisymmetric supercavities. An attempt is made to duplicate sea states seen in open waters. In an effort to track cavity dimensions throughout a wave cycle, an automated cavity tracking script has been developed. Using a high speed camera and the proper software, it is possible to synchronize cavity dimensions with pressure measurements taken inside the cavity. Results regarding supercavity shape, ventilation demand, cavitation parameters and closure methods are presented. It was found that flow unsteadiness caused a decrease in the overall length of the supercavity while having only a minimal effect on the maximum diameter. The supercavity volume varied with cavitation number and a possible relationship between the two is being explored. (Supported by ONR)

  4. Partial liquid ventilation improves lung function in ventilation-induced lung injury.

    PubMed

    Vazquez de Anda, G F; Lachmann, R A; Verbrugge, S J; Gommers, D; Haitsma, J J; Lachmann, B

    2001-07-01

    Disturbances in lung function and lung mechanics are present after ventilation with high peak inspiratory pressures (PIP) and low levels of positive end-expiratory pressure (PEEP). Therefore, the authors investigated whether partial liquid ventilation can re-establish lung function after ventilation-induced lung injury. Adult rats were exposed to high PIP without PEEP for 20 min. Thereafter, the animals were randomly divided into five groups. The first group was killed immediately after randomization and used as an untreated control. The second group received only sham treatment and ventilation, and three groups received treatment with perfluorocarbon (10 mL x kg(-1), 20 mL x kg(-1), and 20 ml x kg(-1) plus an additional 5 mL x kg(-1) after 1 h). The four groups were maintained on mechanical ventilation for a further 2-h observation period. Blood gases, lung mechanics, total protein concentration, minimal surface tension, and small/large surfactant aggregates ratio were determined. The results show that in ventilation-induced lung injury, partial liquid ventilation with different amounts of perflubron improves gas exchange and pulmonary function, when compared to a group of animals treated with standard respiratory care. These effects have been observed despite the presence of a high intra-alveolar protein concentration, especially in those groups treated with 10 and 20 mL of perflubron. The data suggest that replacement of perfluorocarbon, lost over time, is crucial to maintain the constant effects of partial liquid ventilation. PMID:11510811

  5. Reasons for changes in the value of unit pressure of compression products supporting external treatment

    NASA Astrophysics Data System (ADS)

    Kowalski, K.; Ilska, A.; Kłonowska, M.

    2016-07-01

    The paper presents the basics of modelling compression products with intended values of unit pressure for body circumferences with fixed and variable radius of curvature. The derived relationships referring to the dimensions of the fabric's circumferences in a relaxed state of the product were based on Laplace law, local values of the radius of curvature, and the characteristics of stretching and relaxing (deformation) of the knitted fabric, described by experimental relation for the stress and relaxation phase for the 6th hysteresis loop, taking into account confidence intervals. The article indicates the possibilities of using 3D scanning techniques of the human body to identify the radius of curvature of various circumference of the human silhouette, for which the intended value of the unit pressure is designed, and quantitative changes in the body deformation due to compression. Classic method of modelling and design of compression products, based on a cylindrical model of the human body does not provide in each case the intended value of unit pressure, according to specific normative requirements, because it neglects the effect of different values of the radius of curvature of the body circumference and the properties of the viscoelastic knitted fabrics. The model and experimental research allowed for a quantitative and qualitative assessment of the reasons for the changes in the value of unit pressure of compression products supporting the process of external treatment.

  6. Ventilation Inception and Washout, Scaling, and Effects on Hydrodynamic Performance of a Surface Piercing Strut

    NASA Astrophysics Data System (ADS)

    Harwood, Casey; Young, Yin Lu; Ceccio, Steven

    2014-11-01

    High-lift devices that operate at or near a fluid free surface (such as surface-piercing or shallowly-submerged propellers and hydrofoils) are prone to a multiphase flow phenomenon called ventilation, wherein non-condensable gas is entrained in the low-pressure flow, forming a cavity around the body and dramatically altering the global hydrodynamic forces. Experiments are being conducted at the University of Michigan's towing tank using a canonical surface-piercing strut to investigate atmospheric ventilation. The goals of the work are (i) to gain an understanding of the dominant physics in fully wetted, partially ventilated, and fully ventilated flow regimes, (ii) to quantify the effects of governing dimensionless parameters on the transition between flow regimes, and (iii) to develop scaling relations for the transition between flow regimes. Using theoretical arguments and flow visualization techniques, new criteria are developed for classifying flow regimes and transition mechanisms. Unsteady transition mechanisms are described and mapped as functions of the governing non-dimensional parameters. A theoretical scaling relationship is developed for ventilation washout, which is shown to adequately capture the experimentally-observed washout boundary. This material is based upon work supported by the National Science Foundation Graduate Student Research Fellowship under Grant No. DGE 1256260. Support also comes from the Naval Engineering Education Center (Award No. N65540-10-C-003).

  7. An Environmental Control and Life Support System Concept for a Pressurized Lunar Rover

    NASA Technical Reports Server (NTRS)

    Bagdigian, Robert M.; Stambaugh, Imelda

    2010-01-01

    Pressurized rovers can add many attractive capabilities to a human lunar exploration campaign, most notably by extending the reach of astronauts far beyond the immediate vicinities of lunar landers and fixed assets such as habitats. Effective campaigns will depend on an efficient allocation of environmental control and life support system (ECLSS) equipment amongst mobile rovers and fixed habitats such that widespread and sustainable exploration can be achieved. This paper will describe some of the key drivers that influence the design of an ECLSS for a pressurized lunar rover and a conceptual design that has been formulated to address those drivers. Opportunities to realize programmatic and operational efficiencies through commonality of rover ECLSS and extravehicular activity (EVA) equipment have also been explored and will be described. Plans for the inclusion of ECLSS functionality in prototype lunar rovers will be summarized

  8. DEMAND CONTROLLED VENTILATION AND CLASSROOM VENTILATION

    SciTech Connect

    Fisk, William J.; Mendell, Mark J.; Davies, Molly; Eliseeva, Ekaterina; Faulkner, David; Hong, Tienzen; Sullivan, Douglas P.

    2014-01-06

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling. Major findings included: ? The single-location carbon dioxide sensors widely used for demand controlled ventilation frequently have large errors and will fail to effectively control ventilation rates (VRs).? Multi-location carbon dioxide measurement systems with more expensive sensors connected to multi-location sampling systems may measure carbon dioxide more accurately.? Currently-available optical people counting systems work well much of the time but have large counting errors in some situations. ? In meeting rooms, measurements of carbon dioxide at return-air grilles appear to be a better choice than wall-mounted sensors.? In California, demand controlled ventilation in general office spaces is projected to save significant energy and be cost effective only if typical VRs without demand controlled ventilation are very high relative to VRs in codes. Based on the research, several recommendations were developed for demand controlled ventilation specifications in the California Title 24 Building Energy Efficiency Standards.The research on classroom ventilation collected data over two years on California elementary school classrooms to investigate associations between VRs and student illness absence (IA). Major findings included: ? Median classroom VRs in all studied climate zones were below the California guideline, and 40percent lower in portable than permanent buildings.? Overall, one additional L/s per person of VR was associated with 1.6percent less IA. ? Increasing average VRs in California K-12 classrooms from the current average to the required level is estimated to decrease IA by 3.4percent, increasing State attendance-based funding to school districts by $33M, with $6.2 M in increased energy costs. Further VR increases would provide additional benefits

  9. Exposure to mechanical ventilation promotes tolerance to ventilator-induced lung injury by Ccl3 downregulation.

    PubMed

    Blázquez-Prieto, Jorge; López-Alonso, Inés; Amado-Rodríguez, Laura; Batalla-Solís, Estefanía; González-López, Adrián; Albaiceta, Guillermo M

    2015-10-15

    Inflammation plays a key role in the development of ventilator-induced lung injury (VILI). Preconditioning with a previous exposure can damp the subsequent inflammatory response. Our objectives were to demonstrate that tolerance to VILI can be induced by previous low-pressure ventilation, and to identify the molecular mechanisms responsible for this phenomenon. Intact 8- to 12-wk-old male CD1 mice were preconditioned with 90 min of noninjurious ventilation [peak pressure 17 cmH2O, positive end-expiratory pressure (PEEP) 2 cmH2O] and extubated. Seven days later, preconditioned mice and intact controls were submitted to injurious ventilation (peak pressure 20 cmH2O, PEEP 0 cmH2O) for 2 h to induce VILI. Preconditioned mice showed lower histological lung injury scores, bronchoalveolar lavage albumin content, and lung neutrophilic infiltration after injurious ventilation, with no differences in Il6 or Il10 expression. Microarray analyses revealed a downregulation of Calcb, Hspa1b, and Ccl3, three genes related to tolerance phenomena, in preconditioned animals. Among the previously identified genes, only Ccl3, which encodes the macrophage inflammatory protein 1 alpha (MIP-1α), showed significant differences between intact and preconditioned mice after high-pressure ventilation. In separate, nonconditioned animals, treatment with BX471, a specific blocker of CCR1 (the main receptor for MIP-1α), decreased lung damage and neutrophilic infiltration caused by high-pressure ventilation. We conclude that previous exposure to noninjurious ventilation induces a state of tolerance to VILI. Downregulation of the chemokine gene Ccl3 could be the mechanism responsible for this effect. PMID:26472813

  10. Internally supported flexible duct joint. [device for conducting fluids in high pressure systems

    NASA Technical Reports Server (NTRS)

    Kuhn, R. F., Jr. (Inventor)

    1975-01-01

    An internally supported, flexible duct joint for use in conducting fluids under relatively high pressures in systems where relatively large deflection angles must be accommodated is presented. The joint includes a flexible tubular bellows and an elongated base disposed within the bellows. The base is connected through radiating struts to the bellows near mid-portion and to each of the opposite end portions of the bellows through a pivotal connecting body. A motion-controlling linkage is provided for linking the connecting bodies, whereby angular displacement of the joint is controlled and uniformity in the instantaneous bend radius of the duct is achieved as deflection is imposed.

  11. Space Suit Portable Life Support System Rapid Cycle Amine Repackaging and Sub-Scale Test Results

    NASA Technical Reports Server (NTRS)

    Paul, Heather L.; Rivera, Fatonia L.

    2010-01-01

    NASA is developing technologies to meet requirements for an extravehicular activity (EVA) Portable Life Support System (PLSS) for exploration. The PLSS Ventilation Subsystem transports clean, conditioned oxygen to the pressure garment for space suit pressurization and human consumption, and recycles the ventilation gas, removing carbon dioxide, humidity, and trace contaminants. This paper provides an overview of the development efforts conducted at the NASA Johnson Space Center to redesign the Rapid Cycle Amine (RCA) canister and valve assembly into a radial flow, cylindrical package for carbon dioxide and humidity control of the PLSS ventilation loop. Future work is also discussed.

  12. Treatment Options for Central Sleep Apnea: Comparison of Ventilator, Oxygen, and Drug Therapies.

    PubMed

    Yayan, Josef; Rasche, Kurt

    2016-01-01

    Central sleep apnea (CSA) is a sleep-related disorder characterized by pauses in breathing during sleep when the brain respiratory network momentarily interrupts transmission of impulses to the respiratory musculature. CSA presents significant problems being an independent risk factor for cardiovascular events and death. There are several available treatment options according to CSA severity. Currently, adaptive servo-ventilation is considered best for CSA patients. The goal of the present study was to retrospectively investigate different treatment methods employed for CSA, such as different modes of ventilation, oxygen therapy, and drugs to determine the most effective one. Data were obtained from hospital records during 2010-2015. The diagnosis of CSA and the optimal treatment method were supported by polysomnography examinations. Devices used during sleep to support breathing included continuous positive airway pressure, bi-level positive airway pressure, or adaptive servo-ventilation. We classified 71 (2.9 %) patients as having CSA from 2,463 patients with sleep-disordered breathing. Of those 71 patients, 54 (76.1 %, 95 % CI 66.2-86.0 %) were male and 17 (23.9 %, 95 % CI 14.0-33.8 %) were female, and they had a mean age of 67.1 ± 14.1. Four (5.6 %) patients underwent a combination therapy, 39 (54.9 %) received a ventilator in proper ventilation mode, 25 (35.2 %) received oxygen therapy, 7 (9.9 %) received medication, and 4 (5.6 %) received no treatment. We conclude that although the majority of patients needed treatment for central sleep apnea, a clear advantage in using ventilators when compared to oxygen therapy or drug therapy could not be found. PMID:26747067

  13. Predicted Sizes of Pressure-supported HI Clouds in the Outskirts of the Virgo Cluster

    NASA Astrophysics Data System (ADS)

    Burkhart, Blakesley; Loeb, Abraham

    2016-06-01

    Using data from the ALFALFA AGES Arecibo HI survey of galaxies and the Virgo cluster X-ray pressure profiles from XMM-Newton, we investigate the possibility that starless dark HI clumps, also known as “dark galaxies,” are supported by external pressure in the surrounding intercluster medium. We find that the starless HI clump masses, velocity dispersions, and positions allow these clumps to be in pressure equilibrium with the X-ray gas near the virial radius of the Virgo cluster. We predict the sizes of these clumps to range from 1 to 10 kpc, in agreement with the range of sizes found for spatially resolved HI starless clumps outside of Virgo. Based on the predicted HI surface density of the Virgo sources, as well as a sample of other similar resolved ALFALFA HI dark clumps with follow-up optical/radio observations, we predict that most of the HI dark clumps are on the cusp of forming stars. These HI sources therefore mark the transition between starless HI clouds and dwarf galaxies with stars.

  14. Time pressure and coworker support mediate the curvilinear relationship between age and occupational well-being.

    PubMed

    Zacher, Hannes; Jimmieson, Nerina L; Bordia, Prashant

    2014-10-01

    As the proportion of older employees in the workforce is growing, researchers have become increasingly interested in the association between age and occupational well-being. The curvilinear nature of relationships between age and job satisfaction and between age and emotional exhaustion is well-established in the literature, with employees in their late 20s to early 40s generally reporting lower levels of occupational well-being than younger and older employees. However, the mechanisms underlying these curvilinear relationships are so far not well understood due to a lack of studies testing mediation effects. Based on an integration of role theory and research from the adult development and career literatures, this study examined time pressure, work-home conflict, and coworker support as mediators of the relationships between age and job satisfaction and between age and emotional exhaustion. Data came from 771 employees between 17 and 74 years of age in the construction industry. Results showed that employees in their late 20s to early 40s had lower job satisfaction and higher emotional exhaustion than younger and older employees. Time pressure and coworker support fully mediated both the U-shaped relationship between age and job satisfaction and the inversely U-shaped relationship between age and emotional exhaustion. These findings suggest that organizational interventions may help increase the relatively low levels of occupational well-being in certain age groups. PMID:24885685

  15. Behavior of Supported Palladium Oxide Nanoparticles under Reaction Conditions, Studied with near Ambient Pressure XPS.

    PubMed

    Jürgensen, Astrid; Heutz, Niels; Raschke, Hannes; Merz, Klaus; Hergenröder, Roland

    2015-08-01

    Near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) is a promising method to close the "pressure gap", and thus, study the surface composition during heterogeneous reactions in situ. The specialized spectrometers necessary for this analytical technique have recently been adapted to operate with a conventional X-ray source, making it available for routine quantitative analysis in the laboratory. This is shown in the present in situ study of the partial oxidation of 2-propanol catalyzed with PdO nanoparticles supported on TiO2, which was investigated under reaction conditions as a function of gas composition (alcohol-to-oxygen ratio) and temperature. Exposure of the nanoparticles to 2-propanol at 30 °C leads to immediate partial reduction of the PdO, followed by a continuous reduction of the remaining PdO during heating. However, gaseous oxygen inhibits the reduction of PdO below 90 °C, and the oxidation of 2-propanol to carboxylates only occurs in the presence of oxygen above 90 °C. These results support the theory that metallic palladium is the active catalyst material, and they show that environmental conditions affect the nanoparticles and the reaction process significantly. The study also revealed challenges and limitations of this analytical method. Specifically, the intensity and fixed photon energy of a conventional X-ray source limit the spectral resolution and surface sensitivity of lab-based NAP-XPS, which affect precision and accuracy of the quantitative analysis. PMID:26144222

  16. Potential model for single-sided naturally ventilated buildings in China

    SciTech Connect

    Wei, Yin; Guo-qiang, Zhang; Jing, Liu; San-xian, Xia; Xiao, Wang

    2010-09-15

    The paper investigates a single-sided naturally ventilated buildings potential model considering number of factors in China. This model can be used to estimate potential of natural ventilation via local climate data and building parameters. The main goal of the model is to predict natural ventilation hours and hourly ventilation flow rate. In fluid model, formula of single-sided natural ventilation by coupling wind pressure and temperature difference was used to calculate air flow rate. Accordingly, the paper analyzed four typical cities in different climate region in China and calculated pressure difference Pascal hours (PDPH). The results show that single-sided ventilation has fewer adaptive comfort hours than two-sided ventilation and much less ventilation volume. This model provided quantitative information for early stage architectural natural ventilation design and building energy efficiency evaluation. (author)

  17. Metformin attenuates ventilator-induced lung injury

    PubMed Central

    2012-01-01

    Introduction Diabetic patients may develop acute lung injury less often than non-diabetics; a fact that could be partially ascribed to the usage of antidiabetic drugs, including metformin. Metformin exhibits pleiotropic properties which make it potentially beneficial against lung injury. We hypothesized that pretreatment with metformin preserves alveolar capillary permeability and, thus, prevents ventilator-induced lung injury. Methods Twenty-four rabbits were randomly assigned to pretreatment with metformin (250 mg/Kg body weight/day per os) or no medication for two days. Explanted lungs were perfused at constant flow rate (300 mL/min) and ventilated with injurious (peak airway pressure 23 cmH2O, tidal volume ≈17 mL/Kg) or protective (peak airway pressure 11 cmH2O, tidal volume ≈7 mL/Kg) settings for 1 hour. Alveolar capillary permeability was assessed by ultrafiltration coefficient, total protein concentration in bronchoalveolar lavage fluid (BALF) and angiotensin-converting enzyme (ACE) activity in BALF. Results High-pressure ventilation of the ex-vivo lung preparation resulted in increased microvascular permeability, edema formation and microhemorrhage compared to protective ventilation. Compared to no medication, pretreatment with metformin was associated with a 2.9-fold reduction in ultrafiltration coefficient, a 2.5-fold reduction in pulmonary edema formation, lower protein concentration in BALF, lower ACE activity in BALF, and fewer histological lesions upon challenge of the lung preparation with injurious ventilation. In contrast, no differences regarding pulmonary artery pressure and BALF total cell number were noted. Administration of metformin did not impact on outcomes of lungs subjected to protective ventilation. Conclusions Pretreatment with metformin preserves alveolar capillary permeability and, thus, decreases the severity of ventilator-induced lung injury in this model. PMID:22827994

  18. Development of Designer Diamond Technology for High Pressure High Temperature Experiments in Support of Stockpile Stewardship Program

    SciTech Connect

    Vohra, Yogesh, K.

    2009-10-28

    The role of nitrogen in the fabrication of designer diamond was systematically investigated by adding controlled amount of nitrogen in hydrogen/methane/oxygen plasma. This has led to a successful recipe for reproducible fabrication of designer diamond anvils for high-pressure high-temperature research in support of stockpile stewardship program. In the three-year support period, several designer diamonds fabricated with this new growth chemistry were utilized in high-pressure experiments at UAB and Lawrence Livermore National Laboratory. The designer diamond anvils were utilized in high-pressure studies on heavy rare earth metals, high pressure melting studies on metals, and electrical resistance measurements on iron-based layered superconductors under high pressures. The growth chemistry developed under NNSA support can be adapted for commercial production of designer diamonds.

  19. Ventilator-induced lung injury in preterm infants

    PubMed Central

    Carvalho, Clarissa Gutierrez; Silveira, Rita C; Procianoy, Renato Soibelmann

    2013-01-01

    In preterm infants, the need for intubation and mechanical ventilation is associated with ventilator-induced lung injuries and subsequent bronchopulmonary dysplasia. The aim of the present review was to improve the understanding of the mechanisms of injury that involve cytokine-mediated inflammation to contribute to the development of new preventive strategies. Relevant articles were retrieved from the PubMed database using the search terms "ventilator-induced lung injury preterm", "continuous positive airway pressure", "preterm", and "bronchopulmonary dysplasia". The resulting data and other relevant information were divided into several topics to ensure a thorough, critical view of ventilation-induced lung injury and its consequences in preterm infants. The role of pro-inflammatory cytokines (particularly interleukins 6 and 8 and tumor necrosis factor alpha) as mediators of lung injury was assessed. Evidence from studies conducted with animals and human newborns is described. This evidence shows that brief periods of mechanical ventilation is sufficient to induce the release of pro-inflammatory cytokines. Other forms of mechanical and non-invasive ventilation were also analyzed as protective alternatives to conventional mechanical ventilation. It was concluded that non-invasive ventilation, intubation followed by early surfactant administration and quick extubation for nasal continuous positive airway pressure, and strategies that regulate tidal volume and avoid volutrauma (such as volume guarantee ventilation) protect against ventilator-induced lung injury in preterm infants. PMID:24553514

  20. Convexity, Jensen's inequality, and benefits of noisy or biologically variable life support (Keynote Address)

    NASA Astrophysics Data System (ADS)

    Mutch, W. Alan C.

    2005-05-01

    Life support with a mechanical ventilator is used to manage patients with a variety of lung diseases including acute respiratory distress syndrome (ARDS). Recently, management of ARDS has concentrated on ventilating at lower airway pressure using lower tidal volume. A large international study demonstrated a 22% reduction in mortality with the low tidal volume approach. The potential advantages of adding physiologic noise with fractal characteristics to the respiratory rate and tidal volume as delivered by a mechanical ventilator are discussed. A so-called biologically variable ventilator (BVV), incorporating such noise, has been developed. Here we show that the benefits of noisy ventilation - at lower tidal volumes - can be deduced from a simple probabilistic result known as Jensen"s Inequality. Using the local convexity of the pressure-volume relationship in the lung we demonstrate that the addition of noise results in higher mean tidal volume or lower mean airway pressure. The consequence is enhanced gas exchange or less stress on the lungs, both clinically desirable. Jensen"s Inequality has important considerations in engineering, information theory and thermodynamics. Here is an example of the concept applied to medicine that may have important considerations for the clinical management of critically ill patients. Life support devices, such as mechanical ventilators, are of vital use in critical care units and operating rooms. These devices usually have monotonous output. Improving mechanical ventilators and other life support devices may be as simple as adding noise to their output signals.

  1. Nasal mask ventilation is better than face mask ventilation in edentulous patients

    PubMed Central

    Kapoor, Mukul Chandra; Rana, Sandeep; Singh, Arvind Kumar; Vishal, Vindhya; Sikdar, Indranil

    2016-01-01

    Background and Aims: Face mask ventilation of the edentulous patient is often difficult as ineffective seating of the standard mask to the face prevents attainment of an adequate air seal. The efficacy of nasal ventilation in edentulous patients has been cited in case reports but has never been investigated. Material and Methods: Consecutive edentulous adult patients scheduled for surgery under general anesthesia with endotracheal intubation, during a 17-month period, were prospectively evaluated. After induction of anesthesia and administration of neuromuscular blocker, lungs were ventilated with a standard anatomical face mask of appropriate size, using a volume controlled anesthesia ventilator with tidal volume set at 10 ml/kg. In case of inadequate ventilation, the mask position was adjusted to achieve best-fit. Inspired and expired tidal volumes were measured. Thereafter, the face mask was replaced by a nasal mask and after achieving best-fit, the inspired and expired tidal volumes were recorded. The difference in expired tidal volumes and airway pressures at best-fit with the use of the two masks and number of patients with inadequate ventilation with use of the masks were statistically analyzed. Results: A total of 79 edentulous patients were recruited for the study. The difference in expiratory tidal volumes with the use of the two masks at best-fit was statistically significant (P = 0.0017). Despite the best-fit mask placement, adequacy of ventilation could not be achieved in 24.1% patients during face mask ventilation, and 12.7% patients during nasal mask ventilation and the difference was statistically significant. Conclusion: Nasal mask ventilation is more efficient than standard face mask ventilation in edentulous patients. PMID:27625477

  2. [Cardiopulmonary resuscitation: risks and benefits of ventilation].

    PubMed

    Cordioli, Ricardo Luiz; Garelli, Valentina; Lyazidi, Aissam; Suppan, Laurent; Savary, Dominique; Brochard, Laurent; Richard, Jean-Christophe M

    2013-12-11

    Knowledge of the physiological mechanisms that govern cardiopulmonary interactions during cardiopulmonary resuscitation (CPR) allows to better assess risks and benefits of ventilation. Ventilation is required to maintain gas exchange, particularly when CPR is prolonged. Nevertheless, conventional ventilation (bag mask or mechanical ventilation) may be harmful when excessive or when chest compressions are interrupted. In fact large tidal volume and/or rapid respiratory rate may adversely compromise hemodynamic effects of chest compressions. In this regard, international recommendations that give the priority to chest compressions, are meaningful. Continuous flow insufflation with oxygen that generates a moderate positive airway pressure avoids any interruption of chest compressions and prevents the risk of lung injury associated with prolonged resuscitation. PMID:24416979

  3. [Inject-ventilation in bronchoscopy (author's transl)].

    PubMed

    Gebert, E; Deilmann, M; Pedersen, P

    1979-08-01

    Jet ventilation initially described by Sanders has been modified and improved for use with the Storz bronchoscope. Theoretical and technical performance are discussed and the mechanical and physiological properties are dealt with e.g. FiO2, driving and endotracheal pressure, expiratory CO2 concentrations, blood gas analysis, pulmonary artery pressure and electrocardiographic changes. Using this method prolonged diagnostic and surgical procedures, such as cauterisation of bronchial adenoma, removal of foreign bodies from the airways especially of small children and bronchial toilet in status asthmaticus, are rendered free from problems for the anaesthetist. We believe that the inject ventilator is a very useful addition to endotracheal surgery. PMID:495920

  4. A requirement for reduced pressure and modified atmosphere composition in lunar and martian biological life support systems

    NASA Astrophysics Data System (ADS)

    Dixon, Mike; Stasiak, Michael; Wehkamp, Cara Ann; Lawson, Jamie

    The Controlled Environment Systems Research Facility at the PlaceTypeUniversity of Place- NameGuelph (country-regionplaceCanada) represents an extensive collection of variable pressure plant growth chambers devoted to the study of biological systems including plants and microbes, in life support roles for space exploration. To simplify engineering requirements for plant growth structures on the Moon or Mars, lower pressures are required in order to reduce mass and decrease atmospheric leakage. Few facilities exist that can provide low pressure plant growth capabilities coupled with complete control over temperature, vapour pressure deficit (humidity), gas composition, nutrient delivery, and pressure. The Controlled Environment Systems Research Facility maintains five canopy-scale hypobaric plant growth chambers with capabilities ideally suited for low pressure advanced life support research. System performance evaluations during low pressure experiments on radish (Raphanus sativa L. cv. Cherry Bomb II) have demonstrated temperature control of +/- 0.5 ° C, vapour pressure deficit control of +/- 0.5 mb, CO2 injection control of +/- 20 ` ımol mol-1 , and leakage rates of less than 1% per day. Keywords: hypobaric, plant growth chamber, advanced life support, controlled environment, low pressure, atmospheric control

  5. Leaks can dramatically decrease FiO2 on home ventilators: a bench study

    PubMed Central

    2013-01-01

    Background Long term oxygen therapy improves survival in hypoxemic patients with chronic obstructive pulmonary disease (COPD). Because pressure support ventilation with a home care ventilator is largely unsupervised, there is considerable risk of leakage occurring, which could affect delivered FiO2. We have therefore conducted a bench study in order to measure the effect of different levels of O2 supply and degrees of leakage on delivered FiO2. Ventilator tested: Legendair® (Airox™, Pau, France). Thirty-six measures were performed in each four ventilators with zero, 5 and 10 l.min-1 leakage and 1,2,4 and 8 l O2 flow. Findings FiO2 decreased significantly with 5 l.min-1 leakage for all O2 flow rates, and with 10 l.min-1 at 4 and 8 l.min-1 O2. Conclusion During application of NIV on home ventilators, leakage can dramatically decrease inspired FiO2 making it less effective. It is important to know the FiO2 dispensed when NIV is used for COPD at home. We would encourage industry to develop methods for FiO2 regulation Chronic use of NIV for COPD with controlled FiO2 or SpO2 requires further studys. PMID:23870165

  6. Utilizing a Suited Manikin Test Apparatus and Space Suit Ventilation Loop to Evaluate Carbon Dioxide Washout

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda; Conger, Bruce; Korona, Adam; Kanne, Bryan; McMillin, Summer; Paul, Thomas; Norcross, Jason; Alonso, Jesus Delgado; Swickrath, Mike

    2015-01-01

    NASA is pursuing technology development of an Advanced Extravehicular Mobility Unit (AEMU) which is an integrated assembly made up of primarily a pressure garment system and a portable life support subsystem (PLSS). The PLSS is further composed of an oxygen subsystem, a ventilation subsystem, and a thermal subsystem. One of the key functions of the ventilation system is to remove and control the carbon dioxide (CO2) delivered to the crewmember. Carbon dioxide washout is the mechanism by which CO2 levels are controlled within the space suit helmet to limit the concentration of CO2 inhaled by the crew member. CO2 washout performance is a critical parameter needed to ensure proper and robust designs that are insensitive to human variabilities in a space suit. A suited manikin test apparatus (SMTA) was developed to augment testing of the PLSS ventilation loop in order to provide a lower cost and more controlled alternative to human testing. The CO2 removal function is performed by the regenerative Rapid Cycle Amine (RCA) within the PLSS ventilation loop and its performance is evaluated within the integrated SMTA and Ventilation Loop test system. This paper will provide a detailed description of the schematics, test configurations, and hardware components of this integrated system. Results and analysis of testing performed with this integrated system will be presented within this paper.

  7. Gas exchange and intrapulmonary distribution of ventilation during continuous-flow ventilation

    SciTech Connect

    Vettermann, J.; Brusasco, V.; Rehder, K.

    1988-05-01

    In 12 anesthetized paralyzed dogs, pulmonary gas exchange and intrapulmonary inspired gas distribution were compared between continuous-flow ventilation (CFV) and conventional mechanical ventilation (CMV). Nine dogs were studied while they were lying supine, and three dogs were studied while they were lying prone. A single-lumen catheter for tracheal insufflation and a double-lumen catheter for bilateral endobronchial insufflation (inspired O2 fraction = 0.4; inspired minute ventilation = 1.7 +/- 0.3 (SD) 1.kg-1.min-1) were evaluated. Intrapulmonary gas distribution was assessed from regional 133Xe clearances. In dogs lying supine, CO2 elimination was more efficient with endobronchial insufflation than with tracheal insufflation, but the alveolar-arterial O2 partial pressure difference was larger during CFV than during CMV, regardless of the type of insufflation. By contrast, endobronchial insufflation maintained both arterial PCO2 and alveolar-arterial O2 partial pressure difference at significantly lower levels in dogs lying prone than in dogs lying supine. In dogs lying supine, the dependent lung was preferentially ventilated during CMV but not during CFV. In dogs lying prone, gas distribution was uniform with both modes of ventilation. The alveolar-arterial O2 partial pressure difference during CFV in dogs lying supine was negatively correlated with the reduced ventilation of the dependent lung, which suggests that increased ventilation-perfusion mismatching was responsible for the increase in alveolar-arterial O2 partial pressure difference. The more efficient oxygenation during CFV in dogs lying prone suggests a more efficient matching of ventilation to perfusion, presumably because the distribution of blood flow is also nearly uniform.

  8. 46 CFR 108.185 - Ventilation for enclosed classified locations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation for enclosed classified locations. 108.185... enclosed classified locations. (a) The ventilation system for each enclosed classified location must be designed to maintain a pressure differential between the enclosed classified location and each...

  9. 46 CFR 108.185 - Ventilation for enclosed classified locations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation for enclosed classified locations. 108.185... enclosed classified locations. (a) The ventilation system for each enclosed classified location must be designed to maintain a pressure differential between the enclosed classified location and each...

  10. 46 CFR 108.185 - Ventilation for enclosed classified locations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for enclosed classified locations. 108.185... enclosed classified locations. (a) The ventilation system for each enclosed classified location must be designed to maintain a pressure differential between the enclosed classified location and each...

  11. 46 CFR 108.185 - Ventilation for enclosed classified locations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation for enclosed classified locations. 108.185... enclosed classified locations. (a) The ventilation system for each enclosed classified location must be designed to maintain a pressure differential between the enclosed classified location and each...

  12. 46 CFR 108.185 - Ventilation for enclosed classified locations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation for enclosed classified locations. 108.185... enclosed classified locations. (a) The ventilation system for each enclosed classified location must be designed to maintain a pressure differential between the enclosed classified location and each...

  13. High-frequency oscillatory ventilation compared with conventional mechanical ventilation in the treatment of respiratory failure in preterm infants. The HIFI Study Group.

    PubMed

    1989-01-12

    We conducted a multicenter randomized clinical trial to compare the efficacy and safety of high-frequency ventilation with that of conventional mechanical ventilation in the treatment of respiratory failure in preterm infants. Of 673 preterm infants weighing between 750 and 2000 g, 346 were assigned to receive conventional mechanical ventilation and 327 to receive high-frequency oscillatory ventilation. The incidence of bronchopulmonary dysplasia was similar in the two groups (high-frequency ventilation, 40 percent; conventional mechanical ventilation, 41 percent; P = 0.79). High-frequency ventilation did not reduce mortality (18 percent, vs. 17 percent with conventional ventilation; P = 0.73) or the level of ventilatory support during the first 28 days. The crossover rate from high-frequency ventilation to conventional mechanical ventilation was greater than the crossover rate from mechanical to high-frequency ventilation (26 vs. 17 percent; P = 0.01). High-frequency ventilation, as compared with conventional mechanical ventilation, was associated with an increased incidence of pneumoperitoneum of pulmonary origin (3 vs. 1 percent; P = 0.05), grades 3 and 4 intracranial hemorrhage (26 vs. 18 percent; P = 0.02), and periventricular leukomalacia (12 vs. 7 percent; P = 0.05). These results suggest that high-frequency oscillatory ventilation, as used in this trial, does not offer any advantage over conventional mechanical ventilation in the treatment of respiratory failure in preterm infants, and it may be associated with undesirable side effects. PMID:2643039

  14. Adjunct therapies during mechanical ventilation: airway clearance techniques, therapeutic aerosols, and gases.

    PubMed

    Kallet, Richard H

    2013-06-01

    Mechanically ventilated patients in respiratory failure often require adjunct therapies to address special needs such as inhaled drug delivery to alleviate airway obstruction, treat pulmonary infection, or stabilize gas exchange, or therapies that enhance pulmonary hygiene. These therapies generally are supportive in nature rather than curative. Currently, most lack high-level evidence supporting their routine use. This overview describes the rationale and examines the evidence supporting adjunctive therapies during mechanical ventilation. Both mechanistic and clinical research suggests that intrapulmonary percussive ventilation may enhance pulmonary secretion mobilization and might reverse atelectasis. However, its impact on outcomes such ICU stay is uncertain. The most crucial issue is whether aerosolized antibiotics should be used to treat ventilator-associated pneumonia, particularly when caused by multi-drug resistant pathogens. There is encouraging evidence from several studies supporting its use, at least in individual cases of pneumonia non-responsive to systemic antibiotic therapy. Inhaled pulmonary vasodilators provide at least short-term improvement in oxygenation and may be useful in stabilizing pulmonary gas exchange in complex management situations. Small uncontrolled studies suggest aerosolized heparin with N-acetylcysteine might break down pulmonary casts and relieve airway obstruction in patients with severe inhalation injury. Similar low-level evidence suggests that heliox is effective in reducing airway pressure and improving ventilation in various forms of lower airway obstruction. These therapies generally are supportive and may facilitate patient management. However, because they have not been shown to improve patient outcomes, it behooves clinicians to use these therapies parsimoniously and to monitor their effectiveness carefully. PMID:23709200

  15. Review of Residential Ventilation Technologies

    SciTech Connect

    Armin Rudd

    2005-08-30

    This paper reviews current and potential ventilation technologies for residential buildings, including a variety of mechanical systems, natural ventilation, and passive ventilation. with particular emphasis on North American climates and construction.

  16. Pulmonary ventilation/perfusion scan

    MedlinePlus

    V/Q scan; Ventilation/perfusion scan; Lung ventilation/perfusion scan ... A pulmonary ventilation/perfusion scan is actually two tests. They may be done separately or together. During the perfusion scan, a health ...

  17. Pulmonary Congestion at Rest and Abnormal Ventilation During Exercise in Chronic Systolic Heart Failure

    PubMed Central

    Malfatto, Gabriella; Caravita, Sergio; Giglio, Alessia; Rossi, Jessica; Perego, Giovanni B; Facchini, Mario; Parati, Gianfranco

    2015-01-01

    Background In patients with chronic heart failure, abnormal ventilation at cardiopulmonary testing (expressed by minute ventilation-to-carbon dioxide production, or VE/VCO2 slope, and resting end-tidal CO2 pressure) may derive either from abnormal autonomic or chemoreflex regulation or from lung dysfunction induced by pulmonary congestion. The latter hypothesis is supported by measurement of pulmonary capillary wedge pressure, which cannot be obtained routinely but may be estimated noninvasively by measuring transthoracic conductance (thoracic fluid content 1/kΩ) with impedance cardiography. Methods and Results Preliminarily, in 9 patients undergoing invasive hemodynamics during cardiopulmonary testing, we demonstrated a significant relationship between VE/VCO2 slope and resting end-tidal CO2 pressure with baseline and peak pulmonary capillary wedge pressure. Later, noninvasive hemodynamic evaluation by impedance cardiography was performed before cardiopulmonary testing in 190 patients with chronic systolic heart failure and normal lung function (aged 67±3 years, 71% with ischemia, ejection fraction 32±7%, 69% with implantable cardioverter-defibrillator or cardiac resynchronization therapy). In this group, we determined the relationship between abnormal ventilation (VE/VCO2 slope and resting end-tidal CO2 pressure) and transthoracic conductance. In the whole population, thoracic fluid content values were significantly related to VE/VCO2 slope (R=0.63, P<0.0001) and to resting end-tidal CO2 pressure (R=−0.44, P<0.001). Conclusions In patients with chronic heart failure, abnormal ventilation during exercise may be related in part to pulmonary congestion, as detected by resting baseline impedance cardiography. PMID:25944875

  18. Controlling interactions in supported bilayers from weak electrostatic repulsion to high osmotic pressure

    PubMed Central

    Hemmerle, Arnaud; Malaquin, Linda; Charitat, Thierry; Lecuyer, Sigolène; Fragneto, Giovanna; Daillant, Jean

    2012-01-01

    Understanding interactions between membranes requires measurements on well-controlled systems close to natural conditions, in which fluctuations play an important role. We have determined, by grazing incidence X-ray scattering, the interaction potential between two lipid bilayers, one adsorbed on a solid surface and the other floating close by. We find that interactions in this highly hydrated model system are two orders of magnitude softer than in previously reported work on multilayer stacks. This is attributed to the weak electrostatic repulsion due to the small fraction of ionized lipids in supported bilayers with a lower number of defects. Our data are consistent with the Poisson–Boltzmann theory, in the regime where repulsion is dominated by the entropy of counter ions. We also have unique access to very weak entropic repulsion potentials, which allowed us to discriminate between the various models proposed in the literature. We further demonstrate that the interaction potential between supported bilayers can be tuned at will by applying osmotic pressure, providing a way to manipulate these model membranes, thus considerably enlarging the range of biological or physical problems that can be addressed. PMID:23169650

  19. Oxygen toxicity during artificial ventilation

    PubMed Central

    Brewis, R. A. L.

    1969-01-01

    Repeated pulmonary collapse and changes suggestive of a severe alveolar-capillary diffusion defect were observed over a period of 20 days in a patient who was receiving artificial ventilation because of status epilepticus. Profound cyanosis followed attempts to discontinue assisted ventilation. The Bird Mark 8 respirator employed was found to be delivering approximately 90% oxygen on the air-mix setting and pulmonary oxygen toxicity was suspected. Radiological improvement and progressive resolution of the alveolar-capillary block followed gradual reduction of the inspired concentration over nine days. The management and prevention of this complication are discussed. The inspired oxygen concentration should be routinely monitored in patients receiving intermittent positive pressure ventilation, and the concentration should not be higher than that required to maintain adequate oxygenation. The Bird Mark 8 respirator has an inherent tendency to develop high oxygen concentrations on the air-mix setting, and the machine should therefore be driven from a compressed air source unless high concentrations of oxygen are essential. Images PMID:4900444

  20. Multifamily Ventilation Retrofit Strategies

    SciTech Connect

    Ueno, K.; Lstiburek, J.; Bergey, D.

    2012-12-01

    In multifamily buildings, central ventilation systems often have poor performance, overventilating some portions of the building (causing excess energy use), while simultaneously underventilating other portions (causing diminished indoor air quality). BSC and Innova Services Corporation performed a series of field tests at a mid-rise test building undergoing a major energy audit and retrofit, which included ventilation system upgrades.

  1. Guide to Home Ventilation

    SciTech Connect

    2010-10-01

    A fact sheet from the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy: Ventilation refers to the exchange of indoor and outdoor air. Without proper ventilation, an otherwise insulated and airtight house will seal in harmful pollutants, such as carbon monoxide, and moisture that can damage a house.

  2. Advanced support systems development and supporting technologies for Controlled Ecological Life Support Systems (CELSS)

    NASA Technical Reports Server (NTRS)

    Simon, William E.; Li, Ku-Yen; Yaws, Carl L.; Mei, Harry T.; Nguyen, Vinh D.; Chu, Hsing-Wei

    1994-01-01

    A methyl acetate reactor was developed to perform a subscale kinetic investigation in the design and optimization of a full-scale metabolic simulator for long term testing of life support systems. Other tasks in support of the closed ecological life support system test program included: (1) heating, ventilation and air conditioning analysis of a variable pressure growth chamber, (2) experimental design for statistical analysis of plant crops, (3) resource recovery for closed life support systems, and (4) development of data acquisition software for automating an environmental growth chamber.

  3. Is there still a role for high-frequency oscillatory ventilation in neonates, children and adults?

    PubMed

    Hupp, Susan R; Turner, David A; Rehder, Kyle J

    2015-10-01

    Critically ill patients with respiratory pathology often require mechanical ventilation and while low tidal volume ventilation has become the mainstay of treatment, achieving adequate gas exchange may not be attainable with conventional ventilator modalities. In attempt to achieve gas exchange goals and also mitigate lung injury, high frequency ventilation is often implemented which couples low tidal volumes with sustained mean airway pressure. This manuscript presents the physiology of high-frequency oscillatory ventilation, reviews the currently available data on its use and provides strategies and approaches for this mode of ventilation. PMID:26290121

  4. 21 CFR 211.46 - Ventilation, air filtration, air heating and cooling.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Ventilation, air filtration, air heating and... Buildings and Facilities § 211.46 Ventilation, air filtration, air heating and cooling. (a) Adequate ventilation shall be provided. (b) Equipment for adequate control over air pressure, micro-organisms,...

  5. 21 CFR 211.46 - Ventilation, air filtration, air heating and cooling.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Ventilation, air filtration, air heating and... Buildings and Facilities § 211.46 Ventilation, air filtration, air heating and cooling. (a) Adequate ventilation shall be provided. (b) Equipment for adequate control over air pressure, micro-organisms,...

  6. 21 CFR 211.46 - Ventilation, air filtration, air heating and cooling.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Ventilation, air filtration, air heating and... Buildings and Facilities § 211.46 Ventilation, air filtration, air heating and cooling. (a) Adequate ventilation shall be provided. (b) Equipment for adequate control over air pressure, micro-organisms,...

  7. 21 CFR 211.46 - Ventilation, air filtration, air heating and cooling.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Ventilation, air filtration, air heating and... Buildings and Facilities § 211.46 Ventilation, air filtration, air heating and cooling. (a) Adequate ventilation shall be provided. (b) Equipment for adequate control over air pressure, micro-organisms,...

  8. Patient ventilator interfaces: practical aspects in the chronic situation.

    PubMed

    Clini, E

    1997-02-01

    In the ventilator-dependent patient, the nonpsychological problems of the chronic phase relate mainly to aspects of the patient ventilator interface. Humidification, suctioning of secretions, and ventilatory circuit and monitoring are the three most important aspects to which careful attention is needed. Good humidification can be obtained by means of various devices, which can provide humidity directly or indirectly: in the tracheostomized patient, the heat and moisture exchanger appears to be a good method because of its antibacterial properties. Airway suctioning is frequently needed in patients receiving ventilation invasively. Suctioning of secretions might possibly be associated with the risk of major cardiorespiratory complications: bacterial colonization of the airways and the subsequent increased risk of infection should be carefully considered. Problems concerning the ventilatory circuit and monitoring can be specific in patients with a tracheal cannula and those with a nasal/facial interface. Long-term tracheostomy in itself represents a real risk for bacterial colonization, damage to the tracheal mucosa, and to functioning of the vocal cords (both for speech and swallowing): therefore, a switch from invasive to noninvasive ventilatory interface may be proposed. Most problems with the nasal mask interface concern air leakage and the skin mucosal lesions. Two major aspects must be taken into account when considering the long-term effects of noninvasive ventilatory support monitoring: the possible effect of CO2 rebreathing, and the inadequate volume/pressure delivery, so that proper ventilation cannot be achieved. Use of an oral/mouth interface is of limited interest in subjects with restrictive disorders: air gastric distension and orthodontic problems are the most common side-effects in chronic use. PMID:9151529

  9. Recommended Ventilation Strategies for Energy-Efficient Production Homes

    SciTech Connect

    Roberson, J.; Brown, R.; Koomey, J.; Warner, J.; Greenberg, S.

    1998-12-01

    This report evaluates residential ventilation systems for the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR{reg_sign} Homes program and recommends mechanical ventilation strategies for new, low-infiltration, energy-efficient, single-family, ENERGY STAR production (site-built tract) homes in four climates: cold, mixed (cold and hot), hot humid, and hot arid. Our group in the Energy Analysis Department at Lawrence Berkeley National Lab compared residential ventilation strategies in four climates according to three criteria: total annualized costs (the sum of annualized capital cost and annual operating cost), predominant indoor pressure induced by the ventilation system, and distribution of ventilation air within the home. The mechanical ventilation systems modeled deliver 0.35 air changes per hour continuously, regardless of actual infiltration or occupant window-opening behavior. Based on the assumptions and analysis described in this report, we recommend independently ducted multi-port supply ventilation in all climates except cold because this strategy provides the safety and health benefits of positive indoor pressure as well as the ability to dehumidify and filter ventilation air. In cold climates, we recommend that multi-port supply ventilation be balanced by a single-port exhaust ventilation fan, and that builders offer balanced heat-recovery ventilation to buyers as an optional upgrade. For builders who continue to install forced-air integrated supply ventilation, we recommend ensuring ducts are airtight or in conditioned space, installing a control that automatically operates the forced-air fan 15-20 minutes during each hour that the fan does not operate for heating or cooling, and offering ICM forced-air fans to home buyers as an upgrade.

  10. Factors associated with blood oxygen partial pressure and carbon dioxide partial pressure regulation during respiratory extracorporeal membrane oxygenation support: data from a swine model

    PubMed Central

    Park, Marcelo; Mendes, Pedro Vitale; Costa, Eduardo Leite Vieira; Barbosa, Edzangela Vasconcelos Santos; Hirota, Adriana Sayuri; Azevedo, Luciano Cesar Pontes

    2016-01-01

    Objective The aim of this study was to explore the factors associated with blood oxygen partial pressure and carbon dioxide partial pressure. Methods The factors associated with oxygen - and carbon dioxide regulation were investigated in an apneic pig model under veno-venous extracorporeal membrane oxygenation support. A predefined sequence of blood and sweep flows was tested. Results Oxygenation was mainly associated with extracorporeal membrane oxygenation blood flow (beta coefficient = 0.036mmHg/mL/min), cardiac output (beta coefficient = -11.970mmHg/L/min) and pulmonary shunting (beta coefficient = -0.232mmHg/%). Furthermore, the initial oxygen partial pressure and carbon dioxide partial pressure measurements were also associated with oxygenation, with beta coefficients of 0.160 and 0.442mmHg/mmHg, respectively. Carbon dioxide partial pressure was associated with cardiac output (beta coefficient = 3.578mmHg/L/min), sweep gas flow (beta coefficient = -2.635mmHg/L/min), temperature (beta coefficient = 4.514mmHg/ºC), initial pH (beta coefficient = -66.065mmHg/0.01 unit) and hemoglobin (beta coefficient = 6.635mmHg/g/dL). Conclusion In conclusion, elevations in blood and sweep gas flows in an apneic veno-venous extracorporeal membrane oxygenation model resulted in an increase in oxygen partial pressure and a reduction in carbon dioxide partial pressure 2, respectively. Furthermore, without the possibility of causal inference, oxygen partial pressure was negatively associated with pulmonary shunting and cardiac output, and carbon dioxide partial pressure was positively associated with cardiac output, core temperature and initial hemoglobin. PMID:27096671

  11. Uneven distribution of ventilation in acute respiratory distress syndrome

    PubMed Central

    Rylander, Christian; Tylén, Ulf; Rossi-Norrlund, Rauni; Herrmann, Peter; Quintel, Michael; Bake, Björn

    2005-01-01

    Introduction The aim of this study was to assess the volume of gas being poorly ventilated or non-ventilated within the lungs of patients treated with mechanical ventilation and suffering from acute respiratory distress syndrome (ARDS). Methods A prospective, descriptive study was performed of 25 sedated and paralysed ARDS patients, mechanically ventilated with a positive end-expiratory pressure (PEEP) of 5 cmH2O in a multidisciplinary intensive care unit of a tertiary university hospital. The volume of poorly ventilated or non-ventilated gas was assumed to correspond to a difference between the ventilated gas volume, determined as the end-expiratory lung volume by rebreathing of sulphur hexafluoride (EELVSF6), and the total gas volume, calculated from computed tomography images in the end-expiratory position (EELVCT). The methods used were validated by similar measurements in 20 healthy subjects in whom no poorly ventilated or non-ventilated gas is expected to be found. Results EELVSF6 was 66% of EELVCT, corresponding to a mean difference of 0.71 litre. EELVSF6 and EELVCT were significantly correlated (r2 = 0.72; P < 0.001). In the healthy subjects, the two methods yielded almost identical results. Conclusion About one-third of the total pulmonary gas volume seems poorly ventilated or non-ventilated in sedated and paralysed ARDS patients when mechanically ventilated with a PEEP of 5 cmH2O. Uneven distribution of ventilation due to airway closure and/or obstruction is likely to be involved. PMID:15774050

  12. Effects on Lung Function of Small-Volume Conventional Ventilation and High-Frequency Oscillatory Ventilation in a Model of Meconium Aspiration Syndrome.

    PubMed

    Mikusiakova, L Tomcikova; Pistekova, H; Kosutova, P; Mikolka, P; Calkovska, A; Mokra, D

    2015-01-01

    For treatment of severe neonatal meconium aspiration syndrome (MAS), lung-protective mechanical ventilation is essential. This study compared short-term effects of small-volume conventional mechanical ventilation and high-frequency oscillatory ventilation on lung function in experimentally-induced MAS. In conventionally-ventilated rabbits, MAS was induced by intratracheal instillation of meconium suspension (4 ml/kg, 25 mg/ml). Then, animals were ventilated conventionally with small-volume (f-50/min; VT-6 ml/kg) or with high frequency ventilation (f-10/s) for 4 h, with the evaluation of blood gases, ventilatory pressures, and pulmonary shunts. After sacrifice, left lung was saline-lavaged and cells in bronchoalveolar lavage fluid (BALF) were determined. Right lung was used for the estimation of lung edema formation (wet/dry weight ratio). Thiobarbituric acid-reactive substances (TBARS), oxidative damage markers, were detected in lung tissue and plasma. Meconium instillation worsened gas exchange, and induced inflammation and lung edema. Within 4 h of ventilation, high frequency ventilation improved arterial pH and CO2 elimination compared with conventional ventilation. However, no other significant differences in oxygenation, ventilatory pressures, shunts, BALF cell counts, TBARS concentrations, or edema formation were observed between the two kinds of ventilation. We conclude that high frequency ventilation has only a slight advantage over small-volume conventional ventilation in the model of meconium aspiration syndrome in that it improves CO2 elimination. PMID:26017729

  13. Coolant pressure and airflow distribution in a strut-supported transpiration-cooled vane for a gas turbine engine

    NASA Technical Reports Server (NTRS)

    Kaufman, A.; Poferl, D. J.; Richards, H. T.

    1972-01-01

    An analysis to predict pressure and flow distribution in a strut-supported wire-cloth vane was developed. Results were compared with experimental data obtained from room-temperature airflow tests conducted over a range of vane inlet airflow rates from 10.7 to 40.4 g/sec (0.0235 to 0.0890 lb/sec). The analytical method yielded reasonably accurate predictions of vane coolant flow rate and pressure distribution.

  14. Successful Intervention for Pressure Ulcer by Nutrition Support Team: A Case Report.

    PubMed

    Inui, Shigeki; Konishi, Yuko; Yasui, Yoko; Harada, Toshiko; Itami, Satoshi

    2010-01-01

    A 23-year-old woman with heart failure developed pressure ulcer on her sacral area due to a long-term bed rest and impaired hemodynamics. The ulcer improved only slightly after 2 months with povidone-iodine sugar ointment because of severe nausea and anorexia. Then, the nutrition support team (NST) started intervention and estimated the patient's malnutrition from her body weight (30.1 kg), body mass index (BMI) (13.9), triceps skinfold thickness (TSF) (3.5 mm), arm circumference (AC) (17.2 cm) and serum albumin (2.6 g/dl). The NST administrated an enteral nutrition formula through a nasogastric tube and tried to provide meals according to the patient's taste. Although DESIGN score improved to 7 (DESIGN: d2e1s2i1g1n0 = 7) 2 months later, severe nausea prevented the patient from taking any food perorally. However, after nasogastric decannulation, her appetite improved and 1 month later her body weight increased to 32.8 kg, her BMI to 15.2, TSF to 7.5 mm, AC to 19.7 cm and serum albumin to 4.1 g/dl, and the wound completely healed. PMID:20689636

  15. Nondestructive Methods and Special Test Instrumentation Supporting NASA Composite Overwrapped Pressure Vessel Assessments

    NASA Technical Reports Server (NTRS)

    Saulsberry, Regor; Greene, Nathanael; Cameron, Ken; Madaras, Eric; Grimes-Ledesma, Lorie; Thesken, John; Phoenix, Leigh; Murthy, Pappu; Revilock, Duane

    2007-01-01

    Many aging composite overwrapped pressure vessels (COPVs), being used by the National Aeronautics and Space Administration (NASA) are currently under evaluation to better quantify their reliability and clarify their likelihood of failure due to stress rupture and age-dependent issues. As a result, some test and analysis programs have been successfully accomplished and other related programs are still in progress at the NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) and other NASA centers, with assistance from the commercial sector. To support this effort, a group of Nondestructive Evaluation (NDE) experts was assembled to provide NDE competence for pretest evaluation of test articles and for application of NDE technology to real-time testing. Techniques were required to provide assurance that the test article had adequate structural integrity and manufacturing consistency to be considered acceptable for testing and these techniques were successfully applied. Destructive testing is also being accomplished to better understand the physical and chemical property changes associated with progression toward "stress rupture" (SR) failure, and it is being associated with NDE response, so it can potentially be used to help with life prediction. Destructive work also includes the evaluation of residual stresses during dissection of the overwrap, laboratory evaluation of specimens extracted from the overwrap to evaluate physical property changes, and quantitative microscopy to inform the theoretical micromechanics.

  16. Energy efficient engine, high pressure turbine thermal barrier coating. Support technology report

    NASA Technical Reports Server (NTRS)

    Duderstadt, E. C.; Agarwal, P.

    1983-01-01

    This report describes the work performed on a thermal barrier coating support technology task of the Energy Efficient Engine Component Development Program. A thermal barrier coating (TBC) system consisting of a Ni-Cr-Al-Y bond cost layer and ZrO2-Y2O3 ceramic layer was selected from eight candidate coating systems on the basis of laboratory tests. The selection was based on coating microstructure, crystallographic phase composition, tensile bond and bend test results, erosion and impact test results, furnace exposure, thermal cycle, and high velocity dynamic oxidation test results. Procedures were developed for applying the selected TBC to CF6-50, high pressure turbine blades and vanes. Coated HPT components were tested in three kinds of tests. Stage 1 blades were tested in a cascade cyclic test rig, Stage 2 blades were component high cycle fatigue tested to qualify thermal barrier coated blades for engine testing, and Stage 2 blades and Stage 1 and 2 vanes were run in factory engine tests. After completion of the 1000 cycle engine test, the TBC on the blades was in excellent condition over all of the platform and airfoil except at the leading edge above midspan on the suction side of the airfoil. The coating damage appeared to be caused by particle impingement; adjacent blades without TBC also showed evidence of particle impingement.

  17. [Ventilator-associated pneumonia and other infections].

    PubMed

    Bobik, Piotr; Siemiątkowski, Andrzej

    2014-01-01

    One of the fundamental elements of therapy in patients hospitalised in the Intensive Care Unit (ICU) is mechanical ventilation (MV). MV enables sufficient gas exchange in patients with severe respiratory insufficiency, thus preserving the proper functioning of organs and systems. However, clinical and experimental studies show that mechanical ventilation may cause severe complications, e.g. lung injury (VALI, VILI), systemic inflammatory response syndrome (SIRS), and, on rare occasions, multiple organ failure (MOF). Mechanical ventilation and especially endotracheal intubation are associated also with higher risk of infectious complications of the respiratory system: ventilator-associated respiratory infection (VARI) and ventilator-associated pneumonia (VAP). The complications of the MV listed above have a significant influence on the length of treatment and also on the increase of the costs of therapy and mortality of patients who stay in an ICU. These negative effects of supported breathing are the reasons for intensive research to find new biological markers of inflammation and lung injury, more sensitive and specific diagnostic instruments, more effective methods of therapy, and programs of prevention. The purpose of this article is the presentation of current knowledge concerning VAP-related infections, to allow pulmonologists and general practitioners to become more familiar with the problem. Basic and the most important data concerning the definition, epidemiology, pathophysiology, microbiology, diagnostics, treatment, and prevention of VAP have been included. Additionally, ventilator-associated tracheobronchitis (VAT) was discussed. PMID:25133817

  18. Pretest Predictions for Phase II Ventilation Tests

    SciTech Connect

    Yiming Sun

    2001-09-19

    The objective of this calculation is to predict the temperatures of the ventilating air, waste package surface, and concrete pipe walls that will be developed during the Phase II ventilation tests involving various test conditions. The results will be used as inputs to validating numerical approach for modeling continuous ventilation, and be used to support the repository subsurface design. The scope of the calculation is to identify the physical mechanisms and parameters related to thermal response in the Phase II ventilation tests, and describe numerical methods that are used to calculate the effects of continuous ventilation. The calculation is limited to thermal effect only. This engineering work activity is conducted in accordance with the ''Technical Work Plan for: Subsurface Performance Testing for License Application (LA) for Fiscal Year 2001'' (CRWMS M&O 2000d). This technical work plan (TWP) includes an AP-2.21Q, ''Quality Determinations and Planning for Scientific, Engineering, and Regulatory Compliance Activities'', activity evaluation (CRWMS M&O 2000d, Addendum A) that has determined this activity is subject to the YMP quality assurance (QA) program. The calculation is developed in accordance with the AP-3.12Q procedure, ''Calculations''. Additional background information regarding this activity is contained in the ''Development Plan for Ventilation Pretest Predictive Calculation'' (DP) (CRWMS M&O 2000a).

  19. Variability in Mechanical Ventilation: What's All the Noise About?

    PubMed

    Naik, Bhiken I; Lynch, Carl; Durbin, Charles G

    2015-08-01

    Controlled mechanical ventilation is characterized by a fixed breathing frequency and tidal volume. Physiological and mathematical models have demonstrated the beneficial effects of varying tidal volume and/or inspiratory pressure during positive-pressure ventilation. The addition of noise (random changes) to a monotonous nonlinear biological system, such as the lung, induces stochastic resonance that contributes to the recruitment of collapsed alveoli and atelectatic lung segments. In this article, we review the mechanism of physiological pulmonary variability, the principles of noise and stochastic resonance, and the emerging understanding that there are beneficial effects of variability during mechanical ventilation. PMID:25691765

  20. Automated detection of asynchrony in patient-ventilator interaction.

    PubMed

    Mulqueeny, Qestra; Redmond, Stephen J; Tassaux, Didier; Vignaux, Laurence; Jolliet, Philippe; Ceriana, Piero; Nava, Stefano; Schindhelm, Klaus; Lovell, Nigel H

    2009-01-01

    An automated classification algorithm for the detection of expiratory ineffective efforts in patient-ventilator interaction is developed and validated. Using this algorithm, 5624 breaths from 23 patients in a pulmonary ward were examined. The participants (N = 23) underwent both conventional and non-invasive ventilation. Tracings of patient flow, pressure at the airway, and transdiaphragmatic pressure were manually labeled by an expert. Overall accuracy of 94.5% was achieved with sensitivity 58.7% and specificity 98.7%. The results demonstrate the viability of using pattern classification techniques to automatically detect the presence of asynchrony between a patient and their ventilator. PMID:19963896

  1. Ventilating Air-Conditioner

    NASA Technical Reports Server (NTRS)

    Dinh, Khanh

    1994-01-01

    Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

  2. High-frequency ventilation.

    PubMed

    Crawford, M R

    1986-08-01

    Over the last six years high-frequency ventilation has been extensively evaluated both in the clinical and laboratory settings. It is now no longer the great mystery it once was, and it is now no longer believed (as many had hoped), that it will solve all the problems associated with mechanical pulmonary ventilation. Although the technique is safe and appears to cause no harm even in the long term, it has not yet been shown to offer any major advantages over conventional mechanical ventilation. PMID:3530042

  3. Perioperative lung protective ventilation in obese patients.

    PubMed

    Fernandez-Bustamante, Ana; Hashimoto, Soshi; Serpa Neto, Ary; Moine, Pierre; Vidal Melo, Marcos F; Repine, John E

    2015-01-01

    The perioperative use and relevance of protective ventilation in surgical patients is being increasingly recognized. Obesity poses particular challenges to adequate mechanical ventilation in addition to surgical constraints, primarily by restricted lung mechanics due to excessive adiposity, frequent respiratory comorbidities (i.e. sleep apnea, asthma), and concerns of postoperative respiratory depression and other pulmonary complications. The number of surgical patients with obesity is increasing, and facing these challenges is common in the operating rooms and critical care units worldwide. In this review we summarize the existing literature which supports the following recommendations for the perioperative ventilation in obese patients: (1) the use of protective ventilation with low tidal volumes (approximately 8 mL/kg, calculated based on predicted -not actual- body weight) to avoid volutrauma; (2) a focus on lung recruitment by utilizing PEEP (8-15 cmH2O) in addition to recruitment maneuvers during the intraoperative period, as well as incentivized deep breathing and noninvasive ventilation early in the postoperative period, to avoid atelectasis, hypoxemia and atelectrauma; and (3) a judicious oxygen use (ideally less than 0.8) to avoid hypoxemia but also possible reabsorption atelectasis. Obesity poses an additional challenge for achieving adequate protective ventilation during one-lung ventilation, but different lung isolation techniques have been adequately performed in obese patients by experienced providers. Postoperative efforts should be directed to avoid hypoventilation, atelectasis and hypoxemia. Further studies are needed to better define optimum protective ventilation strategies and analyze their impact on the perioperative outcomes of surgical patients with obesity. PMID:25907273

  4. Abdominal Muscle Activity during Mechanical Ventilation Increases Lung Injury in Severe Acute Respiratory Distress Syndrome

    PubMed Central

    Zhang, Xianming; Wu, Weiliang; Zhu, Yongcheng; Jiang, Ying; Du, Juan; Chen, Rongchang

    2016-01-01

    Objective It has proved that muscle paralysis was more protective for injured lung in severe acute respiratory distress syndrome (ARDS), but the precise mechanism is not clear. The purpose of this study was to test the hypothesis that abdominal muscle activity during mechanically ventilation increases lung injury in severe ARDS. Methods Eighteen male Beagles were studied under mechanical ventilation with anesthesia. Severe ARDS was induced by repetitive oleic acid infusion. After lung injury, Beagles were randomly assigned into spontaneous breathing group (BIPAPSB) and abdominal muscle paralysis group (BIPAPAP). All groups were ventilated with BIPAP model for 8h, and the high pressure titrated to reached a tidal volume of 6ml/kg, the low pressure was set at 10 cmH2O, with I:E ratio 1:1, and respiratory rate adjusted to a PaCO2 of 35–60 mmHg. Six Beagles without ventilator support comprised the control group. Respiratory variables, end-expiratory volume (EELV) and gas exchange were assessed during mechanical ventilation. The levels of Interleukin (IL)-6, IL-8 in lung tissue and plasma were measured by qRT-PCR and ELISA respectively. Lung injury scores were determined at end of the experiment. Results For the comparable ventilator setting, as compared with BIPAPSB group, the BIPAPAP group presented higher EELV (427±47 vs. 366±38 ml) and oxygenation index (293±36 vs. 226±31 mmHg), lower levels of IL-6(216.6±48.0 vs. 297.5±71.2 pg/ml) and IL-8(246.8±78.2 vs. 357.5±69.3 pg/ml) in plasma, and lower express levels of IL-6 mRNA (15.0±3.8 vs. 21.2±3.7) and IL-8 mRNA (18.9±6.8 vs. 29.5±7.9) in lung tissues. In addition, less lung histopathology injury were revealed in the BIPAPAP group (22.5±2.0 vs. 25.2±2.1). Conclusion Abdominal muscle activity during mechanically ventilation is one of the injurious factors in severe ARDS, so abdominal muscle paralysis might be an effective strategy to minimize ventilator-induce lung injury. PMID:26745868

  5. Adaptive Servo-Ventilation for Central Sleep Apnea in Systolic Heart Failure

    PubMed Central

    Cowie, Martin R.; Woehrle, Holger; Wegscheider, Karl; Angermann, Christiane; d’Ortho, Marie-Pia; Erdmann, Erland; Levy, Patrick; Simonds, Anita K.; Somers, Virend K.; Zannad, Faiez; Teschler, Helmut

    2016-01-01

    BACKGROUND Central sleep apnea is associated with poor prognosis and death in patients with heart failure. Adaptive servo-ventilation is a therapy that uses a noninvasive ventilator to treat central sleep apnea by delivering servo-controlled inspiratory pressure support on top of expiratory positive airway pressure. We investigated the effects of adaptive servo-ventilation in patients who had heart failure with reduced ejection fraction and predominantly central sleep apnea. METHODS We randomly assigned 1325 patients with a left ventricular ejection fraction of 45% or less, an apnea–hypopnea index (AHI) of 15 or more events (occurrences of apnea or hypopnea) per hour, and a predominance of central events to receive guideline-based medical treatment with adaptive servo-ventilation or guideline-based medical treatment alone (control). The primary end point in the time-to-event analysis was the first event of death from any cause, lifesaving cardiovascular intervention (cardiac transplantation, implantation of a ventricular assist device, resuscitation after sudden cardiac arrest, or appropriate lifesaving shock), or unplanned hospitalization for worsening heart failure. RESULTS In the adaptive servo-ventilation group, the mean AHI at 12 months was 6.6 events per hour. The incidence of the primary end point did not differ significantly between the adaptive servo-ventilation group and the control group (54.1% and 50.8%, respectively; hazard ratio, 1.13; 95% confidence interval [CI], 0.97 to 1.31; P = 0.10). All-cause mortality and cardiovascular mortality were significantly higher in the adaptive servo-ventilation group than in the control group (hazard ratio for death from any cause, 1.28; 95% CI, 1.06 to 1.55; P = 0.01; and hazard ratio for cardiovascular death, 1.34; 95% CI, 1.09 to 1.65; P = 0.006). CONCLUSIONS Adaptive servo-ventilation had no significant effect on the primary end point in patients who had heart failure with reduced ejection fraction and

  6. Noninvasive Respiratory Support.

    PubMed

    Cummings, James J; Polin, Richard A

    2016-01-01

    Mechanical ventilation is associated with increased survival of preterm infants but is also associated with an increased incidence of chronic lung disease (bronchopulmonary dysplasia) in survivors. Nasal continuous positive airway pressure (nCPAP) is a form of noninvasive ventilation that reduces the need for mechanical ventilation and decreases the combined outcome of death or bronchopulmonary dysplasia. Other modes of noninvasive ventilation, including nasal intermittent positive pressure ventilation, biphasic positive airway pressure, and high-flow nasal cannula, have recently been introduced into the NICU setting as potential alternatives to mechanical ventilation or nCPAP. Randomized controlled trials suggest that these newer modalities may be effective alternatives to nCPAP and may offer some advantages over nCPAP, but efficacy and safety data are limited. PMID:26715607

  7. Four-dimensional optical coherence tomography imaging of total liquid ventilated rats

    NASA Astrophysics Data System (ADS)

    Kirsten, Lars; Schnabel, Christian; Gaertner, Maria; Koch, Edmund

    2013-06-01

    Optical coherence tomography (OCT) can be utilized for the spatially and temporally resolved visualization of alveolar tissue and its dynamics in rodent models, which allows the investigation of lung dynamics on the microscopic scale of single alveoli. The findings could provide experimental input data for numerical simulations of lung tissue mechanics and could support the development of protective ventilation strategies. Real four-dimensional OCT imaging permits the acquisition of several OCT stacks within one single ventilation cycle. Thus, the entire four-dimensional information is directly obtained. Compared to conventional virtual four-dimensional OCT imaging, where the image acquisition is extended over many ventilation cycles and is triggered on pressure levels, real four-dimensional OCT is less vulnerable against motion artifacts and non-reproducible movement of the lung tissue over subsequent ventilation cycles, which widely reduces image artifacts. However, OCT imaging of alveolar tissue is affected by refraction and total internal reflection at air-tissue interfaces. Thus, only the first alveolar layer beneath the pleura is visible. To circumvent this effect, total liquid ventilation can be carried out to match the refractive indices of lung tissue and the breathing medium, which improves the visibility of the alveolar structure, the image quality and the penetration depth and provides the real structure of the alveolar tissue. In this study, a combination of four-dimensional OCT imaging with total liquid ventilation allowed the visualization of the alveolar structure in rat lung tissue benefiting from the improved depth range beneath the pleura and from the high spatial and temporal resolution.

  8. Why We Ventilate

    SciTech Connect

    Logue, Jennifer M.; Sherman, Max H.; Price, Phil N.; Singer, Brett C.

    2011-09-01

    It is widely accepted that ventilation is critical for providing good indoor air quality (IAQ) in homes. However, the definition of"good" IAQ, and the most effective, energy efficient methods for delivering it are still matters of research and debate. This paper presents the results of work done at the Lawrence Berkeley National Lab to identify the air pollutants that drive the need for ventilation as part of a larger effort to develop a health-based ventilation standard. First, we present results of a hazard analysis that identified the pollutants that most commonly reach concentrations in homes that exceed health-based standards or guidelines for chronic or acute exposures. Second, we present results of an impact assessment that identified the air pollutants that cause the most harm to the U.S. population from chronic inhalation in residences. Lastly, we describe the implications of our findings for developing effective ventilation standards.

  9. Discontinuation of mechanical ventilation at end-of-life: the ethical and legal boundaries of physician conduct in termination of life support.

    PubMed

    Szalados, James E

    2007-04-01

    End-of-life care in the ICU generally encompasses both the withholding and withdrawal of life support and the administration of palliative care. There is little practical distinction in the specific technology or life-support modality that is limited or removed with respect to the subsequent medical, ethical, or legal analysis. The important ethical issues pertinent to end-of-life care in the ICU at the point-of-life support discontinuation are: (1) the distinction between allowing patients to die in accordance with their wishes and causing them die, (2) the fine line between respecting a patient's wish to die with dignity and control and the risk of subsequent allegations of euthanasia or physician-assisted suicide, and (3) the adjunctive use of medications that simultaneously provide comfort but also may hasten death. The medical and legal issues are summarized, and an algorithm for the discontinuation of mechanical ventilatory support at the end of life is presented. PMID:17368174

  10. A noninvasive high frequency oscillation ventilator: Achieved by utilizing a blower and a valve.

    PubMed

    Yuan, YueYang; Sun, JianGuo; Wang, Baicun; Feng, Pei; Yang, ChongChang

    2016-02-01

    After the High Frequency Oscillatory Ventilation (HFOV) has been applied in the invasive ventilator, the new technique of noninvasive High Frequency Oscillatory Ventilation (nHFOV) which does not require opening the patient's airway has attracted much attention from the field. This paper proposes the design of an experimental positive pressure-controlled nHFOV ventilator which utilizes a blower and a special valve and has three ventilation modes: spontaneous controlled ventilation combining HFOV, time-cycled ventilation combining HFOV (T-HFOV), and continuous positive airway pressure ventilation combining HFOV. Experiments on respiratory model are conducted and demonstrated the feasibility of using nHFOV through the control of fan and valve. The experimental ventilator is able to produce an air flow with small tidal volume (VT) and a large minute ventilation volume (MV) using regular breath tubes and nasal mask (e.g., under T-HFOV mode, with a maximum tidal volume of 100 ml, the minute ventilation volume reached 14 400 ml). In the process of transmission, there is only a minor loss of oscillation pressure. (Under experimental condition and with an oscillation frequency of 2-10 Hz, peak pressure loss was around 0%-50% when it reaches the mask.). PMID:26931897

  11. A noninvasive high frequency oscillation ventilator: Achieved by utilizing a blower and a valve

    NASA Astrophysics Data System (ADS)

    Yuan, YueYang; Sun, JianGuo; Wang, Baicun; Feng, Pei; Yang, ChongChang

    2016-02-01

    After the High Frequency Oscillatory Ventilation (HFOV) has been applied in the invasive ventilator, the new technique of noninvasive High Frequency Oscillatory Ventilation (nHFOV) which does not require opening the patient's airway has attracted much attention from the field. This paper proposes the design of an experimental positive pressure-controlled nHFOV ventilator which utilizes a blower and a special valve and has three ventilation modes: spontaneous controlled ventilation combining HFOV, time-cycled ventilation combining HFOV (T-HFOV), and continuous positive airway pressure ventilation combining HFOV. Experiments on respiratory model are conducted and demonstrated the feasibility of using nHFOV through the control of fan and valve. The experimental ventilator is able to produce an air flow with small tidal volume (VT) and a large minute ventilation volume (MV) using regular breath tubes and nasal mask (e.g., under T-HFOV mode, with a maximum tidal volume of 100 ml, the minute ventilation volume reached 14 400 ml). In the process of transmission, there is only a minor loss of oscillation pressure. (Under experimental condition and with an oscillation frequency of 2-10 Hz, peak pressure loss was around 0%-50% when it reaches the mask.)

  12. Flammable gas cloud build up in a ventilated enclosure.

    PubMed

    Ivings, M J; Gant, S E; Saunders, C J; Pocock, D J

    2010-12-15

    Ventilation is frequently used as a means for preventing the build up of flammable or toxic gases in enclosed spaces. The effectiveness of the ventilation often has to be considered as part of a safety case or risk assessment. In this paper methods for assessing ventilation effectiveness for hazardous area classification are examined. The analysis uses data produced from Computational Fluid Dynamics (CFD) simulations of low-pressure jet releases of flammable gas in a ventilated enclosure. The CFD model is validated against experimental measurements of gas releases in a ventilation-controlled test chamber. Good agreement is found between the model predictions and the experimental data. Analysis of the CFD results shows that the flammable gas cloud volume resulting from a leak is largely dependent on the mass release rate of flammable gas and the ventilation rate of the enclosure. The effectiveness of the ventilation for preventing the build up of flammable gas can therefore be assessed by considering the average gas concentration at the enclosure outlet(s). It is found that the ventilation rate of the enclosure provides a more useful measure of ventilation effectiveness than considering the enclosure air change rate. PMID:20855156

  13. A rational framework for selecting modes of ventilation.

    PubMed

    Mireles-Cabodevila, Eduardo; Hatipoğlu, Umur; Chatburn, Robert L

    2013-02-01

    Mechanical ventilation is a life-saving intervention for respiratory failure and thus has become the cornerstone of the practice of critical care medicine. A mechanical ventilation mode describes the predetermined pattern of patient-ventilator interaction. In recent years there has been a dizzying proliferation of mechanical ventilation modes, driven by technological advances and market pressures, rather than clinical data. The comparison of these modes is hampered by the sheer number of combinations that need to be tested against one another, as well as the lack of a coherent, logical nomenclature that accurately describes a mode. In this paper we propose a logical nomenclature for mechanical ventilation modes, akin to biological taxonomy. Accordingly, the control variable, breath sequence, and targeting schemes for the primary and secondary breaths represent the order, family, genus, and species, respectively, for the described mode. To distinguish unique operational algorithms, a fifth level of distinction, termed variety, is utilized. We posit that such coherent ordering would facilitate comparison and understanding of modes. Next we suggest that the clinical goals of mechanical ventilation may be simplified into 3 broad categories: provision of safe gas exchange; provision of comfort; and promotion of liberation from mechanical ventilation. Safety is achieved via optimization of ventilation-perfusion matching and pressure-volume relationship of the lungs. Comfort is provided by fostering patient-ventilator synchrony. Liberation is promoted by optimization of the weaning experience. Then we follow a paradigm that matches the technological capacity of a particular mode to achieving a specific clinical goal. Finally, we provide the reader with a comparison of existing modes based on these principles. The status quo in mechanical ventilation mode nomenclature impedes communication and comparison of existing mechanical ventilation modes. The proposed model

  14. Lung-protective Ventilation in Patients with Brain Injury: A Multicenter Cross-sectional Study and Questionnaire Survey in China

    PubMed Central

    Luo, Xu-Ying; Hu, Ying-Hong; Cao, Xiang-Yuan; Kang, Yan; Liu, Li-Ping; Wang, Shou-Hong; Yu, Rong-Guo; Yu, Xiang-You; Zhang, Xia; Li, Bao-Shan; Ma, Zeng-Xiang; Weng, Yi-Bing; Zhang, Heng; Chen, De-Chang; Chen, Wei; Chen, Wen-Jin; Chen, Xiu-Mei; Du, Bin; Duan, Mei-Li; Hu, Jin; Huang, Yun-Feng; Jia, Gui-Jun; Li, Li-Hong; Liang, Yu-Min; Qin, Bing-Yu; Wang, Xian-Dong; Xiong, Jian; Yan, Li-Mei; Yang, Zheng-Ping; Dong, Chen-Ming; Wang, Dong-Xin; Zhan, Qing-Yuan; Fu, Shuang-Lin; Zhao, Lin; Huang, Qi-Bing; Xie, Ying-Guang; Huang, Xiao-Bo; Zhang, Guo-Bin; Xu, Wang-Bin; Xu, Yuan; Liu, Ya-Ling; Zhao, He-Ling; Sun, Rong-Qing; Sun, Ming; Cheng, Qing-Hong; Qu, Xin; Yang, Xiao-Feng; Xu, Ming; Shi, Zhong-Hua; Chen, Han; He, Xuan; Yang, Yan-Lin; Chen, Guang-Qiang; Sun, Xiu-Mei; Zhou, Jian-Xin

    2016-01-01

    Background: Over the years, the mechanical ventilation (MV) strategy has changed worldwide. The aim of the present study was to describe the ventilation practices, particularly lung-protective ventilation (LPV), among brain-injured patients in China. Methods: This study was a multicenter, 1-day, cross-sectional study in 47 Intensive Care Units (ICUs) across China. Mechanically ventilated patients (18 years and older) with brain injury in a participating ICU during the time of the study, including traumatic brain injury, stroke, postoperation with intracranial tumor, hypoxic-ischemic encephalopathy, intracranial infection, and idiopathic epilepsy, were enrolled. Demographic data, primary diagnoses, indications for MV, MV modes and settings, and prognoses on the 60th day were collected. Multivariable logistic analysis was used to assess factors that might affect the use of LPV. Results: A total of 104 patients were enrolled in the present study, 87 (83.7%) of whom were identified with severe brain injury based on a Glasgow Coma Scale ≤8 points. Synchronized intermittent mandatory ventilation (SIMV) was the most frequent ventilator mode, accounting for 46.2% of the entire cohort. The median tidal volume was set to 8.0 ml/kg (interquartile range [IQR], 7.0–8.9 ml/kg) of the predicted body weight; 50 (48.1%) patients received LPV. The median positive end-expiratory pressure (PEEP) was set to 5 cmH2O (IQR, 5–6 cmH2O). No PEEP values were higher than 10 cmH2O. Compared with partially mandatory ventilation, supportive and spontaneous ventilation practices were associated with LPV. There were no significant differences in mortality and MV duration between patients subjected to LPV and those were not. Conclusions: Among brain-injured patients in China, SIMV was the most frequent ventilation mode. Nearly one-half of the brain-injured patients received LPV. Patients under supportive and spontaneous ventilation were more likely to receive LPV. Trial Registration: Clinical

  15. WASTE HANDLING BUILDING VENTILATION SYSTEM DESCRIPTION DOCUMENT

    SciTech Connect

    P.A. Kumar

    2000-06-21

    The Waste Handling Building Ventilation System provides heating, ventilation, and air conditioning (HVAC) for the contaminated, potentially contaminated, and uncontaminated areas of the Monitored Geologic Repository's (MGR) Waste Handling Building (WHB). In the uncontaminated areas, the non-confinement area ventilation system maintains the proper environmental conditions for equipment operation and personnel comfort. In the contaminated and potentially contaminated areas, in addition to maintaining the proper environmental conditions for equipment operation and personnel comfort, the contamination confinement area ventilation system directs potentially contaminated air away from personnel in the WHB and confines the contamination within high-efficiency particulate air (HEPA) filtration units. The contamination confinement areas ventilation system creates airflow paths and pressure zones to minimize the potential for spreading contamination within the building. The contamination confinement ventilation system also protects the environment and the public by limiting airborne releases of radioactive or other hazardous contaminants from the WHB. The Waste Handling Building Ventilation System is designed to perform its safety functions under accident conditions and other Design Basis Events (DBEs) (such as earthquakes, tornadoes, fires, and loss of the primary electric power). Additional system design features (such as compartmentalization with independent subsystems) limit the potential for cross-contamination within the WHB. The system provides status of important system parameters and equipment operation, and provides audible and/or visual indication of off-normal conditions and equipment failures. The Waste Handling Building Ventilation System confines the radioactive and hazardous material within the building such that the release rates comply with regulatory limits. The system design, operations, and maintenance activities incorporate ALARA (as low as is

  16. The behaviour of peptides on reverse-phase supports during high-pressure liquid chromatography.

    PubMed Central

    Wilson, K J; Honegger, A; Stötzel, R P; Hughes, G J

    1981-01-01

    High-pressure ('performance') liquid chromatography has been used to investigate the reverse-phase chromatographic behaviour of peptides, ranging in length from 2 to 65 amino acid residues, which have originated from primary-sequence determinations or solution/solid-phase syntheses. By using a pyridine/formate-pyridine/acetate/propan-1-ol buffer system, as previously described [Hughes, Winterhalter & Wilson (1979) FEBS Lett. 108, 81-86], the influence of various experimental parameters were examined. (a) Peptide retention was observed to be temperature-independent between 25 and 55 degrees C. (b) The dependence of chromatographic retention on pH decreases with increasing peptide hydrophobicity. (c) Chromatographic results from C8- and C18-chain-length, as well as from 5 micrometers- and 10 micrometers-particle-size, supports were comparable. (d) The hydrophobic strength of the organic solvent in the mobile phase was observed to decrease: propan-1-ol approximately equal to propan-2-ol greater than acetonitrile much greater than methanol. (e) When gradient rates (% of buffer B/unit time) were systematically decreased, peptide retention decreased in a hyperbolic manner. Comparisons of the peptides chromatographed with respect to their measured retention properties and calculated hydrophobicities were performed by computer analysis. Deviation of peptide chromatographic behaviour was observed to be essentially independent of hydrophobicity, chain length and charge. On the basis of the measured retention properties of the chromatographed peptides, hydrophobic constants for the various amino acid side chains were determined and compared with similar constants available from the literature. PMID:7337711

  17. Physiology of non-invasive respiratory support.

    PubMed

    Alexiou, Stamatia; Panitch, Howard B

    2016-06-01

    Non-invasive ventilation (NIV) is used in neonates to treat extrathoracic and intrathoracic airway obstruction, parenchymal lung disease and disorders of control of breathing. Avoidance of airway intubation is associated with a reduction in the incidence of chronic lung disease among preterm infants with respiratory distress syndrome. Use of nasal continuous positive airway pressure (nCPAP) may help establish and maintain functional residual capacity (FRC), decrease respiratory work, and improve gas exchange. Other modes of non-invasive ventilation, which include heated humidified high-flow nasal cannula therapy (HHHFNC), nasal intermittent mandatory ventilation (NIMV), non-invasive pressure support ventilation (NI-PSV), and bi-level CPAP (SiPAP™), have also been shown to provide additional benefit in improving breathing patterns, reducing work of breathing, and increasing gas exchange when compared with nCPAP. Newer modes, such as neurally adjusted ventilatory assist (NAVA), hold the promise of improving patient-ventilator synchrony and so might ultimately improve outcomes for preterm infants with respiratory distress. PMID:26923501

  18. Associations among environmental supports, physical activity, and blood pressure in African-American adults in the PATH trial.

    PubMed

    Coulon, Sandra M; Wilson, Dawn K; Egan, Brent M

    2013-06-01

    High blood pressure disproportionately affects African-American adults and is a leading cause of stroke and heart attack. Engaging in recommended levels of physical activity reduces blood pressure, and social and physical environmental supports for physical activity may increase engagement in physical activity. Based on social cognitive theory within a bioecological framework, the present study tested hypotheses that perceived peer social support for physical activity and neighborhood walkability would be positively associated with physical activity, and that physical activity would mediate their relation with blood pressure. Baseline data were collected with 434 African-American adults in underserved communities (low income, high crime) participating in the Positive Action for Today's Health (PATH) trial. Perceived peer social support for physical activity and neighborhood walkability were measured with validated surveys. Physical activity was assessed with 7-day accelerometry (moderate-to-vigorous physical activity, min/day) and with a 4-week recall of walking. Three blood pressure assessments were taken by trained staff using standard protocols, with values from the second and third assessments averaged. The sample was predominantly female (63%), overweight (mean body mass index = 30.9, SD = 8.4), and had slightly elevated blood pressures with a mean systolic blood pressure of 132.4 (SD = 17.9) and a mean diastolic blood pressure of 81.4 (SD = 11.0). Results demonstrated that peer social support for physical activity (B = 2.43, p = .02) and neighborhood walkability (B = 2.40, p = .046) were significantly related to average daily moderate-to-vigorous physical activity. Neighborhood walkability was also significantly associated with self-reported average daily walking (B = 8.86, p = .02). Physical activity did not mediate their relation with blood pressure and no significant direct effects of these variables on blood pressure were found. The positive influence of

  19. Aerosol Formation from High-Pressure Sprays for Supporting the Safety Analysis for the Hanford Waste Treatment and Immobilization Plant

    SciTech Connect

    Gauglitz, Phillip A.; Mahoney, Lenna A.; Schonewill, Philip P.; Bontha, Jagannadha R.; Blanchard, Jeremy; Kurath, Dean E.; Daniel, Richard C.; Song, Chen

    2013-03-05

    The Waste Treatment and Immobilization Plant (WTP) at Hanford is being designed and built to pretreat and vitrify waste currently stored in underground tanks at Hanford. One of the postulated events in the hazard analysis for the WTP is a breach in process piping that produces a pressurized spray with small droplets that can be transported into ventilation systems. Literature correlations are currently used for estimating the generation rate and size distribution of aerosol droplets in postulated spray releases. These correlations, however, are based on results obtained from small engineered nozzles using Newtonian liquids that do not contain slurry particles and thus do not accurately represent the fluids and breaches in the WTP. A test program was developed to measure the generation rate of droplets suspended in a test chamber and droplet size distribution from a range of prototypic sprays. A novel test method was developed to allow measurement of sprays from small to very large breaches and also includes the effect of aerosol generation from splatter when the spray impacts on walls. Results show that the aerosol generation rate increases with increasing the orifice area, though with a weaker dependence on orifice area than the currently-used correlation. A comparison of water sprays to slurry sprays with 8 to 20 wt% gibbsite or boehmite particles shows that the presence of slurry particles depresses the release fraction compared to water for droplets above 10 μm and increases the release fraction below this droplet size.

  20. Evaluative Pressure in Mothers: Effects of Situation, Maternal, and Child Characteristics on Autonomy Supportive versus Controlling Behavior

    ERIC Educational Resources Information Center

    Grolnick, Wendy S.; Price, Carrie E.; Beiswenger, Krista L.; Sauck, Christine C.

    2007-01-01

    This study examined the effects of situational pressure and maternal characteristics (social contingent self-worth, controlling parenting attitudes) on mothers' autonomy support versus control in the social domain. Sixty 4th-grade children and their mothers worked on a laboratory task in preparation for meeting new children, with mothers in either…

  1. Evaluation of Family Health Education to Build Social Support for Long-Term Control of High Blood Pressure.

    ERIC Educational Resources Information Center

    Morisky, Donald E.; And Others

    1985-01-01

    An educational program was implemented to improve family member support for medical compliance among hypertensive patients. Family members were interviewed, counseled, and provided with a booklet for the purpose of educating and involving them in the home management of high blood pressure. Results of this program are presented and analyzed.…

  2. Rescue Ventilation Through a Small-Bore Transtracheal Cannula in Severe Hypoxic Pigs Using Expiratory Ventilation Assistance

    PubMed Central

    Hamaekers, Ankie E.; van der Beek, Tim; Theunissen, Maurice

    2015-01-01

    BACKGROUND: Suction-generated expiratory ventilation assistance (EVA) has been proposed as a way to facilitate bidirectional ventilation through a small-bore transtracheal cannula (TC). In this study, we investigated the efficiency of ventilation with EVA for restoring oxygenation and ventilation in a pig model of acute hypoxia. METHODS: Six pigs (61–76 kg) were anesthetized and ventilated (intermittent positive pressure ventilation) via a cuffed endotracheal tube (ETT). Monitoring lines were placed, and a 75-mm long, 2-mm inner diameter TC was inserted. After the baseline recordings, the ventilator was disconnected. After 2 minutes of apnea, reoxygenation with EVA was initiated through the TC and continued for 15 minutes with the ETT occluded. In the second part of the study, the experiment was repeated with the ETT either partially obstructed or left open. Airway pressures and hemodynamic data were recorded, and arterial blood gases were measured. Descriptive statistical analysis was performed. RESULTS: With a completely or partially obstructed upper airway, ventilation with EVA restored oxygenation to baseline levels in all animals within 20 seconds. In a completely obstructed airway, Paco2 remained stable for 15 minutes. At lesser degrees of airway obstruction, the time to reoxygenation was delayed. Efficacy probably was limited when the airway was completely unobstructed, with 2 of 6 animals having a Pao2 <85 mm Hg even after 15 minutes of ventilation with EVA and a mean Paco2 increased up to 90 mm Hg. CONCLUSIONS: In severe hypoxic pigs, ventilation with EVA restored oxygenation quickly in case of a completely or partially obstructed upper airway. Reoxygenation and ventilation were less efficient when the upper airway was completely unobstructed. PMID:25565319

  3. Cardiopulmonary effects of intermittent mandatory ventilation.

    PubMed

    Douglas, M E; Downs, J B

    1980-01-01

    IMV is a combination of spontaneous and mechanical ventilation. For numerous reasons, IMV is potentially more advantageous than conventional techniques. By maintaining spontaneous breathing, mechanical augmentation can be titrated to adjust alveolar minute ventilation levels to normal, thereby decreasing the incidence of respiratory alkalemia. There are major differences between the cardiopulmonary effects of IMV and conventional mechanical ventilation. Spontaneous inspiration decreases Ppl and results in better distribution of inspired gas, a better V/Q, and less physiological dead space. In addition, transmural filling pressures, venous return, and cardiac output are more normal than during conventional mechanical ventilation. Maintenance of spontaneous ventilation lowers mean Paw and pulmonary vascular resistance. If venous admixture occurs, it can be minimized by titrating PEEP. Thus, more effective therapy for hypoxemia is possible. If spontaneous breathing is to persist and be efective, work-of-breathing must be minimized. This can be accomplished best when a continuous flow of gas provides optimal CPAP to maintain FRC and to minimize the effects of decreased compliance without depressing cardiac function. PMID:7007253

  4. Ventilating Patient with Refractory Hypercarbia: Use of APRV Mode.

    PubMed

    Arshad, Zia; Prakash, Ravi; Aggarwal, Swati; Yadav, Sapna

    2016-01-01

    A 70-year-old patient referred to our critical care unit with the diagnosis of type II respiratory failure with shock. Patient was a known case of COPD for last 20 years. His chest radiology revealed bilateral infiltrates. Patient was managed conservatively in the form of antibiotics, vasopressor and ventilatory support with SIMV/VC mode. After ventilation with SIMV/VC mode for half an hour his blood gases revealed increasing PaCO2 levels. The same result was obtained with PC mode and ASV and his PaCO2 level reached above 170 mmHg. Then APRV mode was tried with modified settings. The results obtained were satisfactory and in next 24 hours PaCO2 decreased to <66mmHg along with an increasing P/F ratio. APRV is the not recommended as primary mode of ventilation in COPD but in resistant cases it can be helpful as it improves alveolar recruitment and pressure support is added to reduce hypercapnia. PMID:26894156

  5. Ventilating Patient with Refractory Hypercarbia: Use of APRV Mode

    PubMed Central

    Prakash, Ravi; Aggarwal, Swati; Yadav, Sapna

    2016-01-01

    A 70-year-old patient referred to our critical care unit with the diagnosis of type II respiratory failure with shock. Patient was a known case of COPD for last 20 years. His chest radiology revealed bilateral infiltrates. Patient was managed conservatively in the form of antibiotics, vasopressor and ventilatory support with SIMV/VC mode. After ventilation with SIMV/VC mode for half an hour his blood gases revealed increasing PaCO2 levels. The same result was obtained with PC mode and ASV and his PaCO2 level reached above 170 mmHg. Then APRV mode was tried with modified settings. The results obtained were satisfactory and in next 24 hours PaCO2 decreased to <66mmHg along with an increasing P/F ratio. APRV is the not recommended as primary mode of ventilation in COPD but in resistant cases it can be helpful as it improves alveolar recruitment and pressure support is added to reduce hypercapnia. PMID:26894156

  6. Protective Ventilation of Preterm Lambs Exposed to Acute Chorioamnionitis Does Not Reduce Ventilation-Induced Lung or Brain Injury

    PubMed Central

    Barton, Samantha K.; Moss, Timothy J. M.; Hooper, Stuart B.; Crossley, Kelly J.; Gill, Andrew W.; Kluckow, Martin; Zahra, Valerie; Wong, Flora Y.; Pichler, Gerhard; Galinsky, Robert; Miller, Suzanne L.

    2014-01-01

    Background The onset of mechanical ventilation is a critical time for the initiation of cerebral white matter (WM) injury in preterm neonates, particularly if they are inadvertently exposed to high tidal volumes (VT) in the delivery room. Protective ventilation strategies at birth reduce ventilation-induced lung and brain inflammation and injury, however its efficacy in a compromised newborn is not known. Chorioamnionitis is a common antecedent of preterm birth, and increases the risk and severity of WM injury. We investigated the effects of high VT ventilation, after chorioamnionitis, on preterm lung and WM inflammation and injury, and whether a protective ventilation strategy could mitigate the response. Methods Pregnant ewes (n = 18) received intra-amniotic lipopolysaccharide (LPS) 2 days before delivery, instrumentation and ventilation at 127±1 days gestation. Lambs were either immediately euthanased and used as unventilated controls (LPSUVC; n = 6), or were ventilated using an injurious high VT strategy (LPSINJ; n = 5) or a protective ventilation strategy (LPSPROT; n = 7) for a total of 90 min. Mean arterial pressure, heart rate and cerebral haemodynamics and oxygenation were measured continuously. Lungs and brains underwent molecular and histological assessment of inflammation and injury. Results LPSINJ lambs had poorer oxygenation than LPSPROT lambs. Ventilation requirements and cardiopulmonary and systemic haemodynamics were not different between ventilation strategies. Compared to unventilated lambs, LPSINJ and LPSPROT lambs had increases in pro-inflammatory cytokine expression within the lungs and brain, and increased astrogliosis (p<0.02) and cell death (p<0.05) in the WM, which were equivalent in magnitude between groups. Conclusions Ventilation after acute chorioamnionitis, irrespective of strategy used, increases haemodynamic instability and lung and cerebral inflammation and injury. Mechanical ventilation is a potential contributor

  7. Flexible and self-powered temperature–pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials

    PubMed Central

    Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; Di, Chong-an; Zhu, Daoben

    2015-01-01

    Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature–pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of <0.1 K and a high-pressure-sensing sensitivity of up to 28.9 kPa−1. More importantly, these dual-parameter sensors can be self-powered with outstanding sensing performance. The excellent sensing properties of MFSOTE-based devices, together with their unique advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements. PMID:26387591

  8. Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; di, Chong-An; Zhu, Daoben

    2015-09-01

    Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of <0.1 K and a high-pressure-sensing sensitivity of up to 28.9 kPa-1. More importantly, these dual-parameter sensors can be self-powered with outstanding sensing performance. The excellent sensing properties of MFSOTE-based devices, together with their unique advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

  9. Out-of-hospital noninvasive ventilation: epidemiology, technology and equipment

    PubMed Central

    Baird, John Scott; Ravindranath, Thyyar M.

    2012-01-01

    Noninvasive ventilation has been utilized successfully in the pre- and out-of-hospital settings for a variety of disorders, including respiratory distress syndrome in neonates, neurologic and pulmonary diseases in infants and children, and heart failure as well as chronic obstructive pulmonary disease in adults. A variety of interfaces as well as mechanical positive pressure devices have been used: simple continuous positive airway pressure devices are available which do not require sophisticated equipment, while a broad spectrum of ventilators have been used to provide bilevel positive airway pressure. Extensive training of transport teams may be important, particularly when utilizing bilevel positive airway pressure in infants and children. PMID:22802995

  10. Elective use of the Ventrain for upper airway obstruction during high-frequency jet ventilation.

    PubMed

    Fearnley, Robert A; Badiger, Sheela; Oakley, Richard J; Ahmad, Imran

    2016-09-01

    The safety of high pressure source ventilation (jet ventilation) is dependent upon upper airway patency to facilitate adequate passive expiration and prevent increasing intrathoracic pressure and its associated deleterious sequelae. Distortions in airway anatomy may make passive expiration inadequate or impossible in some patients. We report the elective use of the Ventrain device to provide ventilation in a clinical setting of upper airway obstruction in a patient with post radiation fibrosis that had previously prevented passive expiration during attempted high pressure source ventilation. PMID:27555171

  11. Protocol: inspiratory muscle training for promoting recovery and outcomes in ventilated patients (IMPROVe): a randomised controlled trial

    PubMed Central

    Leditschke, I Anne; Paratz, Jennifer D; Boots, Robert J

    2012-01-01

    Introduction Inspiratory muscle weakness is a known consequence of mechanical ventilation and a potential contributor to difficulty in weaning from ventilatory support. Inspiratory muscle training (IMT) reduces the weaning period and increases the likelihood of successful weaning in some patients. However, it is not known how this training affects the residual inspiratory muscle fatigability following successful weaning nor patients' quality of life or functional outcomes. Methods and analysis This dual centre study includes two concurrent randomised controlled trials of IMT in adult patients who are either currently ventilator-dependent (>7 days) (n=70) or have been recently weaned from mechanical ventilation (>7 days) in the past week (n=70). Subjects will be stable, alert and able to actively participate and provide consent. There will be concealed allocation to either treatment (IMT) or usual physiotherapy (including deep breathing exercises without a resistance device). Primary outcomes are inspiratory muscle fatigue resistance and maximum inspiratory pressures. Secondary outcomes are quality of life (Short Form-36v2, EQ-5D), functional status (Acute Care Index of Function), rate of perceived exertion (Borg Scale), intensive care length of stay (days), post intensive care length of stay (days), rate of reintubation (%) and duration of ventilation (days). Ethics and dissemination Ethics approval has been obtained from relevant institutions, and results will be published with a view to influencing physiotherapy practice in the management of long-term ventilator-dependent patients to accelerate weaning and optimise rehabilitation outcomes. Trial registration number ACTRN12610001089022. PMID:22389363

  12. Noninvasive ventilation and the upper airway: should we pay more attention?

    PubMed

    Oppersma, Eline; Doorduin, Jonne; van der Heijden, Erik H F M; van der Hoeven, Johannes G; Heunks, Leo M A

    2013-01-01

    In an effort to reduce the complications related to invasive ventilation, the use of noninvasive ventilation (NIV) has increased over the last years in patients with acute respiratory failure. However, failure rates for NIV remain high in specific patient categories. Several studies have identified factors that contribute to NIV failure, including low experience of the medical team and patient-ventilator asynchrony. An important difference between invasive ventilation and NIV is the role of the upper airway. During invasive ventilation the endotracheal tube bypasses the upper airway, but during NIV upper airway patency may play a role in the successful application of NIV. In response to positive pressure, upper airway patency may decrease and therefore impair minute ventilation. This paper aims to discuss the effect of positive pressure ventilation on upper airway patency and its possible clinical implications, and to stimulate research in this field. PMID:24314000

  13. Noninvasive ventilation and the upper airway: should we pay more attention?

    PubMed Central

    2013-01-01

    In an effort to reduce the complications related to invasive ventilation, the use of noninvasive ventilation (NIV) has increased over the last years in patients with acute respiratory failure. However, failure rates for NIV remain high in specific patient categories. Several studies have identified factors that contribute to NIV failure, including low experience of the medical team and patient–ventilator asynchrony. An important difference between invasive ventilation and NIV is the role of the upper airway. During invasive ventilation the endotracheal tube bypasses the upper airway, but during NIV upper airway patency may play a role in the successful application of NIV. In response to positive pressure, upper airway patency may decrease and therefore impair minute ventilation. This paper aims to discuss the effect of positive pressure ventilation on upper airway patency and its possible clinical implications, and to stimulate research in this field. PMID:24314000

  14. Forced oscillation assessment of respiratory mechanics in ventilated patients

    PubMed Central

    Navajas, Daniel; Farré, Ramon

    2001-01-01

    The forced oscillation technique (FOT) is a method for non-invasively assessing respiratory mechanics that is applicable both in paralysed and non-paralysed patients. As the FOT requires a minimal modification of the conventional ventilation setting and does not interfere with the ventilation protocol, the technique is potentially useful to monitor patient mechanics during invasive and noninvasive ventilation. FOT allows the assessment of the respiratory system linearity by measuring resistance and reactance at different lung volumes or end-expiratory pressures. Moreover, FOT allows the physician to track the changes in patient mechanics along the ventilation cycle. Applying FOT at different frequencies may allow the physician to interpret patient mechanics in terms of models with pathophysiological interest. The current methodological and technical experience make possible the implementation of portable and compact computerised FOT systems specifically addressed to its application in the mechanical ventilation setting. PMID:11178220

  15. Spatial distribution of ventilation and perfusion: mechanisms and regulation.

    PubMed

    Glenny, Robb W; Robertson, H Thomas

    2011-01-01

    With increasing spatial resolution of regional ventilation and perfusion, it has become more apparent that ventilation and blood flow are quite heterogeneous in the lung. A number of mechanisms contribute to this regional variability, including hydrostatic gradients, pleural pressure gradients, lung compressibility, and the geometry of the airway and vascular trees. Despite this marked heterogeneity in both ventilation and perfusion, efficient gas exchange is possible through the close regional matching of the two. Passive mechanisms, such as the shared effect of gravity and the matched branching of vascular and airway trees, create efficient gas exchange through the strong correlation between ventilation and perfusion. Active mechanisms that match local ventilation and perfusion play little if no role in the normal healthy lung but are important under pathologic conditions. PMID:23737178

  16. Current concepts of protective ventilation during general anaesthesia.

    PubMed

    Serpa Neto, Ary; Schultz, Marcus J; Slutsky, Arthur S

    2015-01-01

    Mechanical ventilation with high tidal volumes (VT) has been common practice in operating theatres because this strategy recruits collapsed lung tissue and improves ventilation-perfusion mismatch, thus decreasing the need for high inspired oxygen concentrations. Positive end-expiratory pressure (PEEP) was not used routinely because it was thought to impair cardiovascular function. Over the past two decades there have been advances in our understanding of the causes and importance of ventilation-induced lung injury based on studies in animals with healthy lungs, and trials in critically ill patients with and without acute respiratory distress syndrome. Recent data from randomised controlled trials in patients receiving ventilation during general anaesthesia for surgery have demonstrated that lung-protective strategies (use of low VT, use of PEEP if indicated, and avoidance of excessive oxygen concentrations) are also of importance during intraoperative ventilation. PMID:26561993

  17. Incidence of Parental Support and Pressure on Their Children’s Motivational Processes towards Sport Practice Regarding Gender

    PubMed Central

    Amado, Diana

    2015-01-01

    Grounded in Self-Determination Theory, structural equation modeling (SEM) with the aim of examining how parental support/pressure could influence their children´s motivational processes in sport was conducted, as well as the models´ differences in operability regarding gender. The sample size was 321 children ranging in age from 10 to 16 years old who were athletes from Extremadura, and 321 parents (included only the father or mother more involved with the sport of his or her child). 175 participants were male and 146 were female from individual (n = 130), and team sports (n=191). A questionnaire was conducted to assess parental perception of support/pressure and another questionnaire was conducted to measure satisfaction of basic psychological needs, type of motivation and enjoyment/boredom showed by their children towards sport practice. Results revealed that parental pressure negatively predicted satisfaction of the basic psychological needs. It also emerged as a strong positive predictor of intrinsic motivation and negative predictor of amotivation. Moreover, intrinsic motivation emerged as positive predictor of enjoyment and a negative predictor of boredom, whereas amotivation positively predicted boredom and negatively predicted enjoyment. Furthermore, results showed there were mean differences by gender: male athletes perceived greater parental pressure. Hence, it is necessary to decrease parental pressure towards their children in sport, with the aim of making them more motivated and enjoy, promoting positive consequences. PMID:26039062

  18. Preoperational test report, recirculation ventilation systems

    SciTech Connect

    Clifton, F.T.

    1997-11-11

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  19. Ultra-protective ventilation and hypoxemia.

    PubMed

    Gattinoni, Luciano

    2016-01-01

    Partial extracorporeal CO2 removal allows a decreasing tidal volume without respiratory acidosis in patients with acute respiratory distress syndrome. This, however, may be associated with worsening hypoxemia, due to several mechanisms, such as gravitational and reabsorption atelectasis, due to a decrease in mean airway pressure and a critically low ventilation-perfusion ratio, respectively. In addition, an imbalance between alveolar and artificial lung partial pressures of nitrogen may accelerate the process. Finally, the decrease in the respiratory quotient, leading to unrecognized alveolar hypoxia and monotonous low plateau pressures preventing critical opening, may contribute to hypoxemia. PMID:27170273

  20. Assessment of mechanical ventilation parameters on respiratory mechanics.

    PubMed

    Pidaparti, Ramana M; Koombua, Kittisak; Ward, Kevin R

    2012-01-01

    Better understanding of airway mechanics is very important in order to avoid lung injuries for patients undergoing mechanical ventilation for treatment of respiratory problems in intensive-care medicine, as well as pulmonary medicine. Mechanical ventilation depends on several parameters, all of which affect the patient outcome. As there are no systematic numerical investigations of the role of mechanical ventilation parameters on airway mechanics, the objective of this study was to investigate the role of mechanical ventilation parameters on airway mechanics using coupled fluid-solid computational analysis. For the airway geometry of 3 to 5 generations considered, the simulation results showed that airflow velocity increased with increasing airflow rate. Airway pressure increased with increasing airflow rate, tidal volume and positive end-expiratory pressure (PEEP). Airway displacement and airway strains increased with increasing airflow rate, tidal volume and PEEP form mechanical ventilation. Among various waveforms considered, sine waveform provided the highest airflow velocity and airway pressure while descending waveform provided the lowest airway pressure, airway displacement and airway strains. These results combined with optimization suggest that it is possible to obtain a set of mechanical ventilation strategies to avoid lung injuries in patients. PMID:22136584

  1. A miniature mechanical ventilator for newborn mice.

    PubMed

    Kolandaivelu, K; Poon, C S

    1998-02-01

    Transgenic/knockout mice with pre-defined mutations have become increasingly popular in biomedical research as models of human diseases. In some instances, the resulting mutation may cause cardiorespiratory distress in the neonatal or adult animals and may necessitate resuscitation. Here we describe the design and testing of a miniature and versatile ventilator that can deliver varying ventilatory support modes, including conventional mechanical ventilation and high-frequency ventilation, to animals as small as the newborn mouse. With a double-piston body chamber design, the device circumvents the problem of air leakage and obviates the need for invasive procedures such as endotracheal intubation, which are particularly important in ventilating small animals. Preliminary tests on newborn mice as early as postnatal day O demonstrated satisfactory restoration of pulmonary ventilation and the prevention of respiratory failure in mutant mice that are prone to respiratory depression. This device may prove useful in the postnatal management of transgenic/knockout mice with genetically inflicted respiratory disorders. PMID:9475887

  2. Non-invasive ventilation in chronic obstructive pulmonary disease: management of acute type 2 respiratory failure.

    PubMed

    Roberts, C M; Brown, J L; Reinhardt, A K; Kaul, S; Scales, K; Mikelsons, C; Reid, K; Winter, R; Young, K; Restrick, L; Plant, P K

    2008-10-01

    Non-invasive ventilation (NIV) in the management of acute type 2 respiratory failure in patients with chronic obstructive pulmonary disease (COPD) represents one of the major technical advances in respiratory care over the last decade. This document updates the 2002 British Thoracic Society guidance and provides a specific focus on the use of NIV in COPD patients with acute type 2 respiratory failure. While there are a variety of ventilator units available most centres now use bi-level positive airways pressure units and this guideline refers specifically to this form of ventilatory support although many of the principles encompassed are applicable to other forms of NIV. The guideline has been produced for the clinician caring for COPD patients in the emergency and ward areas of acute hospitals. PMID:18975486

  3. Performance and Life Tests of a Regenerative Blower for EVA Suit Ventilation

    NASA Technical Reports Server (NTRS)

    Izenson, Mike; Chen, Weibo; Paul, Heather L.; Jennings, Mallory A.

    2011-01-01

    Ventilation fans for future space suits must meet demanding performance specifications, satisfy stringent safety requirements for operation in an oxygen atmosphere, and be able to increase output to operate in buddy mode. A regenerative blower is an attractive choice due to its ability to meet these requirements at low operating speed. This paper describes progress in the development and testing of a regenerative blower designed to meet requirements for ventilation subsystems in a future space suit Portable Life Support Systems (PLSS). The blower assembly includes a custom-designed motor that has significantly improved in efficiency during this development effort. The blower was tested at both nominal and buddy mode operating points and head/flow performance and power consumption were measured. The blower was operated for over 1000 hours to demonstrate safe operation in an oxygen test loop at prototypical pressures. In addition, the blower demonstrated operation with the introduction of simulated lunar dust.

  4. Ventilation technologies scoping study

    SciTech Connect

    Walker, Iain S.; Sherman, Max H.

    2003-09-30

    This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the needs of California, determining residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and level of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  5. Comparison of ventilatory and haemodynamic effects of BIPAP and S-IMV/PSV for postoperative short-term ventilation in patients after coronary artery bypass grafting.

    PubMed

    Kazmaier, S; Rathgeber, J; Buhre, W; Buscher, H; Busch, T; Mensching, K; Sonntag, H

    2000-10-01

    The aim of the present multiple cross-over study was to compare the effects of biphasic positive airway pressure (BIPAP) ventilation with synchronized intermittent mandatory ventilation combined with pressure support ventilation (S-IMV/PSV) in sedated and awake patients after coronary artery bypass grafting (CABG) surgery. Twenty-four patients with no evidence of preoperative respiratory dysfunction and an uncomplicated intraoperative course were investigated. The patients were randomly assigned to one of two groups starting with either BIPAP or S-IMV/PSV mode. Haemodynamic measurements and blood gas analyses were performed during sedation with 2.0 mg kg(-1) h(-1) propofol in the primary mode, after switching to the alternative ventilatory mode, and in the primary mode again. The same sequence of measurements was repeated in awake patients who had reached extubation criteria. In awake patients, PSV was performed instead of S-IMV. Statistical analysis of data was performed using non-parametric tests. Inspiratory peak pressure increased significantly during S-IMV/PSV in sedated patients in both groups. Other ventilatory parameters did not differ significantly between BIPAP and S-IMV/PSV in both groups. Similarly, haemodynamic parameters and blood-gas analyses did not vary with the ventilatory mode. Our results demonstrate that BIPAP ventilation has comparable effects on haemodynamics and pulmonary gas exchange compared with S-IMV/PSV and PSV when used for short-term ventilatory support in patients after cardiac surgery. PMID:11050517

  6. The role of external pressure and support on teacher choices related to evolution curriculum in the secondary biology classroom

    NASA Astrophysics Data System (ADS)

    Oschman, Scot

    The scientific community strongly and virtually universally supports the teaching of biological evolution in our public schools. However, there are many in the general public who object to the teaching of biological evolution in our nation's science classrooms. Groups such as Answers in Genesis and the Discovery Institute, along with parents, students, school boards, and school administrators are alleged by many in the scientific and science education communities to be pressuring teachers in a variety of ways regarding the teaching of evolution. The purpose of this study was to examine the sources of, extent of, and ways in which science teachers deal with external influences that attempt to alter their science curriculum related to the teaching of the theory of biological evolution in order to support it, deemphasize it or remove it from their classrooms. It also attempted to determine the impact these outside influences have on evolution education in the classroom. Internal influences were examined in order to ascertain other possible reasons why teachers might or might not de-emphasize, omit, or teach evidence contrary to evolution. Two thousand cover letters were sent out to high school biology teachers selected at random from three states in the U.S. Registry of Teachers, directing them to a web site where they could complete the questionnaire online. One hundred seventy eight teachers responded to the survey. The statistical analyses used in this study to examine the results included analysis of variance (ANOVA), independent samples t tests for means comparisons, as well as a variety of descriptive statistics. This study found that 59% of the teachers who responded had experienced some form of pressure related to their evolution curriculum, and that the majority of this pressure came from students, groups or individuals not affiliated with their school district, and parents. The most common manifestations of pressure were to teach that evolution was "only" a

  7. Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems

    SciTech Connect

    Sherman, Max H.; Walker, Iain S.

    2011-04-01

    Existing ventilation standards, including American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) Standard 62.2, specify continuous operation of a defined mechanical ventilation system to provide minimum ventilation, with time-based intermittent operation as an option. This requirement ignores several factors and concerns including: other equipment such as household exhaust fans that might incidentally provide ventilation, negative impacts of ventilation when outdoor pollutant levels are high, the importance of minimizing energy use particularly during times of peak electricity demand, and how the energy used to condition air as part of ventilation system operation changes with outdoor conditions. Dynamic control of ventilation systems can provide ventilation equivalent to or better than what is required by standards while minimizing energy costs and can also add value by shifting load during peak times and reducing intake of outdoor air contaminants. This article describes the logic that enables dynamic control of whole-house ventilation systems to meet the intent of ventilation standards and demonstrates the dynamic ventilation system control concept through simulations and field tests of the Residential Integrated Ventilation-Energy Controller (RIVEC).

  8. [Independent lung ventilation for asymmetric injury: case report as a demonstration of common challenge].

    PubMed

    Lebedinskiĭ, K M; Artiukov, D A; Borisov, M V; Gromova, T A; Slivin, O A

    2014-01-01

    The article deals with a case of conventional mechanical ventilation in 75 y.o. woman with the background of uncompensated diabetes mellitus, suffering from bilateral pneumonia with predominantly left-sided lesion and severe sepsis. The conventional mechanical ventilation with high pressure levels led to arterial hypoxemia with P/F ratio 52. Independent lung ventilation immediately increased oxygenation up to P/F ratio 225 and evidently improved left lung aeration. The case demonstrates that while applying high pressures to open alveoli, we could not only provoke ventilator-induced lung injury and low cardiac output, but also "squeeze out" pulmonary perfusion from ventilated areas to non-ventilated ones with less intraalveolar pressure levels. PMID:25549491

  9. Central Fan Integrated Ventilation Systems

    SciTech Connect

    2009-05-12

    This information sheet describes one example of a ventilation system design, a central fan integrated supply (CFIS) system, a mechanical ventilation and pollutant source control to ensure that there is reasonable indoor air quality inside the house.

  10. Personalizing mechanical ventilation for acute respiratory distress syndrome.

    PubMed

    Berngard, S Clark; Beitler, Jeremy R; Malhotra, Atul

    2016-03-01

    Lung-protective ventilation with low tidal volumes remains the cornerstone for treating patient with acute respiratory distress syndrome (ARDS). Personalizing such an approach to each patient's unique physiology may improve outcomes further. Many factors should be considered when mechanically ventilating a critically ill patient with ARDS. Estimations of transpulmonary pressures as well as individual's hemodynamics and respiratory mechanics should influence PEEP decisions as well as response to therapy (recruitability). This summary will emphasize the potential role of personalized therapy in mechanical ventilation. PMID:27076966

  11. Personalizing mechanical ventilation for acute respiratory distress syndrome

    PubMed Central

    Beitler, Jeremy R.; Malhotra, Atul

    2016-01-01

    Lung-protective ventilation with low tidal volumes remains the cornerstone for treating patient with acute respiratory distress syndrome (ARDS). Personalizing such an approach to each patient’s unique physiology may improve outcomes further. Many factors should be considered when mechanically ventilating a critically ill patient with ARDS. Estimations of transpulmonary pressures as well as individual’s hemodynamics and respiratory mechanics should influence PEEP decisions as well as response to therapy (recruitability). This summary will emphasize the potential role of personalized therapy in mechanical ventilation. PMID:27076966

  12. Strategies to support prevention, identification and management of pressure ulcers in the community.

    PubMed

    Payne, Drew

    2016-06-01

    Pressure ulcers are classified as serious incidents, cause pain and distress, and are a source of infection. Unlike patients in hospital, those in the community spend only a small amount of time with healthcare practitioners, so strategies are required to ensure they remain protected against pressure damage when community nurses are not with them. A risk assessment should be carried out to outline a patient's risks and used to develop a strategy for that person. Patients have different risks so prevention strategies need to be tailored individually. Strategies, which cover issues such as pressure-relieving equipment, mattress type, mobility aids and nutrition, should be monitored to ensure they continue to meet patients' needs, as their health, carers and other matters may change. Patients and their carers may need education on ulcers, including on myths, as it is essential they are involved. PMID:27297572

  13. Central nervous system patholgoy associated with mask ventilation in the very low birthweight infant: a new etiology for intracerebellar hemorrhages.

    PubMed

    Pape, K E; Armstrong, D L; Fitzhardinge, P M

    1976-10-01

    Mask-applied ventilatory support was noted to cause severe head molding in infants with birthweights under 1,501 gm. To determine if this molding was detrimental to the infant, the neonatal course and autopsy findings were reviewed for 106 infants. Twenty significant intracerebellar hemorrhages were found. An association between these hemorrhages and mask-applied positive pressure ventilation was demonstrated (P = .05). This relationship was maintained when all cases of generalized bleeding dyscrasia were removed (P = .021). It is proposed that the distortional forces produced by the mask attachment, together with the buffeting effect of intermittent positive-pressure ventilation, are causally related to the production of intracerebellar hemorrhages by direct contusion, by ischemic stasis, or by altered venous drainage. The authors urge strong caution when dealing with the small premature infant in using any attachment device that causes molding of the cranial vault, particularly in the occipital area. PMID:787912

  14. Social Support Is Associated with Blood Pressure Responses in Parents Caring for Children with Developmental Disabilities

    ERIC Educational Resources Information Center

    Gallagher, Stephen; Whiteley, Jenny

    2012-01-01

    The present study tested whether parents caring for children with developmental disabilities would have higher blood pressure compared to parents of typically developing children (controls). It also examined the psychosocial factors underlying this observation. Thirty-five parents of children with developmental disability and thirty controls…

  15. How to Plan Ventilation Systems.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1963-01-01

    Ventilation systems for factory safety demand careful planning. The increased heat loads and new processes of industry have introduced complex ventilation problems in--(1) ventilation supply, (2) duct work design, (3) space requirements, (4) hood face velocities, (5) discharge stacks, and (6) building eddies. This article describes and diagrams…

  16. Overall Ventilation System Flow Network Calculation for Site Recommendation

    SciTech Connect

    Jeff J. Steinhoff

    2001-08-02

    The scope of this calculation is to determine ventilation system resistances, pressure drops, airflows, and operating cost estimates for the Site Recommendation (SR) design as detailed in the ''Site Recommendation Subsurface Layout'' (BSC (Bechtel SAIC Company) 2001a). The statutory limit for emplacement of waste in Yucca Mountain is 70,000 metric tons of uranium (MTU) and is considered the base case for this report. The objective is to determine the overall repository system ventilation flow network for the monitoring phase during normal operations and to provide a basis for the system description document design descriptions. Any values derived from this calculation will not be used to support construction, fabrication, or procurement. The work scope is identified in the ''Technical Work Plan for Subsurface Design Section FY01 Work Activities'' (CRWMS M&O 2001, pp. 6 and 13). In accordance with the technical work plan this calculation was prepared in accordance with AP-3.12Q, ''Calculations'' and other procedures invoked by AP-3.12Q. It also incorporates the procedure AP-SI1.Q, ''Software Management''.

  17. Brief mechanical ventilation impacts airway cartilage properties in neonatal lambs

    PubMed Central

    Kim, Minwook; Pugarelli, Joan; Miller, Thomas L.; Wolfson, Marla R.; Dodge, George R.; Shaffer, Thomas H.

    2012-01-01

    Ultrasound imaging allows in vivo assessment of tracheal kinetics and cartilage structure. To date, the impact of mechanical ventilation (MV) on extracellular matrix (ECM) in airway cartilage is unclear, but an indication of its functional and structural change may support the development of protective therapies. The objective of this study was to characterize changes in mechanical properties of the neonatal airway during MV with alterations in cartilage ECM. Trachea segments were isolated in a neonatal lamb model; ultrasound dimensions and pressure-volume relationships were measured on sham (no MV; n = 6) and MV (n = 7) airways for 4 h. Tracheal cross-sections were harvested at 4 h, tissues were fixed and stained, and Fourier transform infrared imaging spectroscopy (FT-IRIS) was performed. Over 4 h of MV, bulk modulus (28%) and elastic modulus (282%) increased. The MV tracheae showed higher collagen, proteoglycan content, and collagen integrity (new tissue formation); whereas no changes were seen in the controls. These data are clinically relevant in that airway properties can be correlated with MV and changes in cartilage extracellular matrix. Mechanical ventilation increases the in vivo dimensions of the trachea, and is associated with evidence of airway tissue remodeling. Injury to the neonatal airway from MV may have relevance for the development of tracheomalacia. We demonstrated active airway tissue remodeling during MV using a FT-IRIS technique which identifies changes in ECM. PMID:22170596

  18. Ventilation Systems Operating Experience Review for Fusion Applications

    SciTech Connect

    Cadwallader, Lee Charles

    1999-12-01

    This report is a collection and review of system operation and failure experiences for air ventilation systems in nuclear facilities. These experiences are applicable for magnetic and inertial fusion facilities since air ventilation systems are support systems that can be considered generic to nuclear facilities. The report contains descriptions of ventilation system components, operating experiences with these systems, component failure rates, and component repair times. Since ventilation systems have a role in mitigating accident releases in nuclear facilities, these data are useful in safety analysis and risk assessment of public safety. An effort has also been given to identifying any safety issues with personnel operating or maintaining ventilation systems. Finally, the recommended failure data were compared to an independent data set to determine the accuracy of individual values. This comparison is useful for the International Energy Agency task on fusion component failure rate data collection.

  19. Laboratory Ventilation and Safety.

    ERIC Educational Resources Information Center

    Steere, Norman V.

    1965-01-01

    In order to meet the needs of both safety and economy, laboratory ventilation systems must effectively remove air-borne toxic and flammable materials and at the same time exhaust a minimum volume of air. Laboratory hoods are the most commonly used means of removing gases, dusts, mists, vapors, and fumed from laboratory operations. To be effective,…

  20. Measure Guideline: Ventilation Cooling

    SciTech Connect

    Springer, D.; Dakin, B.; German, A.

    2012-04-01

    The purpose of this measure guideline on ventilation cooling is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

  1. RESIDENTIAL VENTILATION STUDY

    EPA Science Inventory

    This project evaluated the effectiveness, first costs and operational costs of various types of residential ventilation systems in three different climates in the U.S. The Agency, through its Energy Star Program, recommends that builders construct homes that are energy efficient ...

  2. Space station ventilation study

    NASA Technical Reports Server (NTRS)

    Colombo, G. V.; Allen, G. E.

    1972-01-01

    A ventilation system design and selection method which is applicable to any manned vehicle were developed. The method was used to generate design options for the NASA 33-foot diameter space station, all of which meet the ventilation system design requirements. System characteristics such as weight, volume, and power were normalized to dollar costs for each option. Total system costs for the various options ranged from a worst case $8 million to a group of four which were all approximately $2 million. A system design was then chosen from the $2 million group and is presented in detail. A ventilation system layout was designed for the MSFC space station mockup which provided comfortable, efficient ventilation of the mockup. A conditioned air distribution system design for the 14-foot diameter modular space station, using the same techniques, is also presented. The tradeoff study resulted in the selection of a system which costs $1.9 million, as compared to the alternate configuration which would have cost $2.6 million.

  3. The influence of music during mechanical ventilation and weaning from mechanical ventilation: A review.

    PubMed

    Hetland, Breanna; Lindquist, Ruth; Chlan, Linda L

    2015-01-01

    Mechanical ventilation (MV) causes many distressing symptoms. Weaning, the gradual decrease in ventilator assistance leading to termination of MV, increases respiratory effort, which may exacerbate symptoms and prolong MV. Music, a non-pharmacological intervention without side effects may benefit patients during weaning from mechanical ventilatory support. A narrative review of OVID Medline, PsychINFO, and CINAHL databases was conducted to examine the evidence for the use of music intervention in MV and MV weaning. Music intervention had a positive impact on ventilated patients; 16 quantitative and 2 qualitative studies were identified. Quantitative studies included randomized clinical trials (10), case controls (3), pilot studies (2) and a feasibility study. Evidence supports music as an effective intervention that can lesson symptoms related to MV and promote effective weaning. It has potential to reduce costs and increase patient satisfaction. However, more studies are needed to establish its use during MV weaning. PMID:26227333

  4. Effective Ventilation Strategies for Obese Patients Undergoing Bariatric Surgery: A Literature Review.

    PubMed

    Hu, Xin Yan

    2016-02-01

    Obesity causes major alterations in pulmonary mechanics. Obese patients undergoing bariatric surgery present mechanical ventilation-related challenges that may lead to perioperative complications. Databases were systematically searched for clinical trials of ventilation maneuvers for obese patients and bariatric surgery. Thirteen randomized controlled trials were selected. The quality of the studies was evaluated with the Critical Appraisal Skills Programme tool, and a matrix was developed to present the essential components of the studies. Eight strategies of ventilation maneuvers were identified. Recruitment maneuvers followed by positive end-expiratory pressure (PEEP) consistently demonstrated effectiveness in obese patients undergoing bariatric surgery. Pressure-controlled ventilation and volume-controlled ventilation did not differ significantly in their efficacy. Noninvasive positive pressure ventilation (NIPPV) during induction was effective in preventing atelectasis and increasing the duration of safe apnea. Equal ratio ventilation can be a useful ventilation strategy. Recruitment maneuvers followed by PEEP are effective ventilation strategies for obese patients undergoing bariatric surgery. During induction, NIPPV provides further benefit. Future studies are needed to examine the postoperative effects of recruitment maneuvers with PEEP as well as the efficacy and safety of equal ratio ventilation. PMID:26939387

  5. Project Design Concept Primary Ventilation System

    SciTech Connect

    MCGREW, D.L.

    2000-10-02

    Tank Farm Restoration and Safe Operation (TFRSO), Project W-3 14 was established to provide upgrades that would improve the reliability and extend the system life of portions of the waste transfer, electrical, ventilation, instrumentation and control systems for the Hanford Site Tank Farms. An assessment of the tank farm system was conducted and the results are documented in system assessment reports. Based on the deficiencies identified in the tank farm system assessment reports, and additional requirements analysis performed in support of the River Protection Project (RPP), an approved scope for the TFRSO effort was developed and documented in the Upgrade Scope Summary Report (USSR), WHC-SD-W314-RPT-003, Rev. 4. The USSR establishes the need for the upgrades and identifies the specific equipment to be addressed by this project. This Project Design Concept (PDC) is in support of the Phase 2 upgrades and provides an overall description of the operations concept for the W-314 Primary Ventilation Systems. Actual specifications, test requirements, and procedures are not included in this PDC. The PDC is a ''living'' document, which will be updated throughout the design development process to provide a progressively more detailed description of the W-314 Primary Ventilation Systems design. The Phase 2 upgrades to the Primary Ventilation Systems shall ensure that the applicable current requirements are met for: Regulatory Compliance; Safety; Mission Requirements; Reliability; and Operational Requirements.

  6. Perioperative lung-protective ventilation strategy reduces postoperative pulmonary complications in patients undergoing thoracic and major abdominal surgery.

    PubMed

    Park, Sang-Heon

    2016-02-01

    The occurrence of postoperative pulmonary complications is strongly associated with increased hospital mortality and prolonged postoperative hospital stays. Although protective lung ventilation is commonly used in the intensive care unit, low tidal volume ventilation in the operating room is not a routine strategy. Low tidal volume ventilation, moderate positive end-expiratory pressure, and repeated recruitment maneuvers, particularly for high-risk patients undergoing major abdominal surgery, can reduce postoperative pulmonary complications. Facilitating perioperative bundle care by combining prophylactic and postoperative positive-pressure ventilation with intraoperative lung-protective ventilation may be helpful to reduce postoperative pulmonary complications. PMID:26885294

  7. Perioperative lung-protective ventilation strategy reduces postoperative pulmonary complications in patients undergoing thoracic and major abdominal surgery

    PubMed Central

    2016-01-01

    The occurrence of postoperative pulmonary complications is strongly associated with increased hospital mortality and prolonged postoperative hospital stays. Although protective lung ventilation is commonly used in the intensive care unit, low tidal volume ventilation in the operating room is not a routine strategy. Low tidal volume ventilation, moderate positive end-expiratory pressure, and repeated recruitment maneuvers, particularly for high-risk patients undergoing major abdominal surgery, can reduce postoperative pulmonary complications. Facilitating perioperative bundle care by combining prophylactic and postoperative positive-pressure ventilation with intraoperative lung-protective ventilation may be helpful to reduce postoperative pulmonary complications. PMID:26885294

  8. Heliox Improves Carbon Dioxide Removal during Lung Protective Mechanical Ventilation.

    PubMed

    Beurskens, Charlotte J; Brevoord, Daniel; Lagrand, Wim K; van den Bergh, Walter M; Vroom, Margreeth B; Preckel, Benedikt; Horn, Janneke; Juffermans, Nicole P

    2014-01-01

    Introduction. Helium is a noble gas with low density and increased carbon dioxide (CO2) diffusion capacity. This allows lower driving pressures in mechanical ventilation and increased CO2 diffusion. We hypothesized that heliox facilitates ventilation in patients during lung-protective mechanical ventilation using low tidal volumes. Methods. This is an observational cohort substudy of a single arm intervention study. Twenty-four ICU patients were included, who were admitted after a cardiac arrest and mechanically ventilated for 3 hours with heliox (50% helium; 50% oxygen). A fixed protective ventilation protocol (6 mL/kg) was used, with prospective observation for changes in lung mechanics and gas exchange. Statistics was by Bonferroni post-hoc correction with statistical significance set at P < 0.017. Results. During heliox ventilation, respiratory rate decreased (25 ± 4 versus 23 ± 5 breaths min(-1), P = 0.010). Minute volume ventilation showed a trend to decrease compared to baseline (11.1 ± 1.9 versus 9.9 ± 2.1 L min(-1), P = 0.026), while reducing PaCO2 levels (5.0 ± 0.6 versus 4.5 ± 0.6 kPa, P = 0.011) and peak pressures (21.1 ± 3.3 versus 19.8 ± 3.2 cm H2O, P = 0.024). Conclusions. Heliox improved CO2 elimination while allowing reduced minute volume ventilation in adult patients during protective mechanical ventilation. PMID:25548660

  9. Heliox Improves Carbon Dioxide Removal during Lung Protective Mechanical Ventilation

    PubMed Central

    Beurskens, Charlotte J.; Brevoord, Daniel; Lagrand, Wim K.; van den Bergh, Walter M.; Vroom, Margreeth B.; Preckel, Benedikt; Horn, Janneke; Juffermans, Nicole P.

    2014-01-01

    Introduction. Helium is a noble gas with low density and increased carbon dioxide (CO2) diffusion capacity. This allows lower driving pressures in mechanical ventilation and increased CO2 diffusion. We hypothesized that heliox facilitates ventilation in patients during lung-protective mechanical ventilation using low tidal volumes. Methods. This is an observational cohort substudy of a single arm intervention study. Twenty-four ICU patients were included, who were admitted after a cardiac arrest and mechanically ventilated for 3 hours with heliox (50% helium; 50% oxygen). A fixed protective ventilation protocol (6 mL/kg) was used, with prospective observation for changes in lung mechanics and gas exchange. Statistics was by Bonferroni post-hoc correction with statistical significance set at P < 0.017. Results. During heliox ventilation, respiratory rate decreased (25 ± 4 versus 23 ± 5 breaths min−1, P = 0.010). Minute volume ventilation showed a trend to decrease compared to baseline (11.1 ± 1.9 versus 9.9 ± 2.1 L min−1, P = 0.026), while reducing PaCO2 levels (5.0 ± 0.6 versus 4.5 ± 0.6 kPa, P = 0.011) and peak pressures (21.1 ± 3.3 versus 19.8 ± 3.2 cm H2O, P = 0.024). Conclusions. Heliox improved CO2 elimination while allowing reduced minute volume ventilation in adult patients during protective mechanical ventilation. PMID:25548660

  10. Proposed testing protocols for commercial kitchen ventilation research

    SciTech Connect

    Parikh, J.S. )

    1991-03-01

    Commercial kitchen ventilation systems significantly impact energy use and peak energy demand in foodservice establishments. However, the amount of ventilation exhaust required by different building codes and standards varies widely. Moreover, there is no industry-wide accepted testing procedure that quantifies and verifies exhaust capture and addresses the various types of cooking equipment used in commercial kitchens. This report provides a review of some requirements and practices which are currently in use. Proposals aimed at developing a more uniform approach to ventilation are discussed, including proposals for cooking and ventilation test protocols. Information obtained through a literature search and solicitation of information from cooking appliance and ventilation equipment manufacturers supports the conclusion that additional research and testing is needed to develop methods to establish ventilation requirements of commercial cooking equipment. Based on information gathered, and a meeting with industry representatives, draft test protocols were developed. The proposed protocols call for separate testing of cooking equipment and exhaust hoods. Tests of cooking equipment would be intended to characterize the effluent produced by specific equipment and cooking processes, and to facilitate equipment categorization with respect to cooking surface temperature and effluent generation rates. Using this information on cooking equipment, ventilation hoods would be tested to develop test procedures to determine ventilation requirements for specific hood and cooking equipment combinations. 12 refs., 7 tabs.

  11. Airway Injury from Initiating Ventilation in Preterm Sheep

    PubMed Central

    Hillman, Noah H.; Kallapur, Suhas G.; Pillow, J. Jane; Moss, Timothy J. M.; Polglase, Graeme R.; Nitsos, Ilias; Jobe, Alan H.

    2009-01-01

    Premature infants exposed to ventilation are at risk of developing bronchopulmonary dysplasia (BPD) and persistent lung disease in childhood. We report where injury occurred within the lung following brief ventilation at birth. Preterm sheep (129d gestation) were ventilated with an escalating VT to 15mL/kg by 15 min to injure the lungs, with the placental circulation intact (Fetal) or after delivery (Newborn). Fetal lambs were returned to the uterus for 2h 45min, while Newborn lambs were maintained with gentle ventilatory support for the same period. The control group was not ventilated. Bronchoalveolar lavage fluid (BALF) and lung tissue were analysed. In both Fetal and Newborn lambs, ventilation caused bronchial epithelial disruption in medium-sized airways. Egr-1, MCP-1, IL-6, and IL-1β mRNA increased in lung tissue from Fetal and Newborn lambs. Egr-1, MCP-1 and IL-6 mRNA were induced in mesenchymal cells surrounding small airways, whereas IL-1β mRNA localized to the epithelium of medium/small airways. Ventilation caused loss of HSP70 mRNA from the bronchial epithelium, but induced mRNA in smooth muscle surrounding large airways. HSP70 protein decreased in lung tissue and increased in BALF with ventilation. Initiation of ventilation induced a stress response and inflammatory cytokines in small and medium-sized airways. PMID:19816239

  12. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, A.; Bergey, D.

    2014-02-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  13. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, Armin; Bergey, Daniel

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  14. Parameter identification of a rotor supported in a pressurized bearing lubricated with water

    NASA Technical Reports Server (NTRS)

    Grant, John W.; Muszynska, Agnes; Bently, Donald E.

    1994-01-01

    A rig for testing an externally pressurized (hydrostatic), water-lubricated bearing was developed. Applying a nonsynchronous sweep frequency, rotating perturbation force with a constant amplitude as an input, rotor vibration response data was acquired in Bode and Dynamic Stiffness formats. Using this data, the parameters of the rotor/bearing system were identified. The rotor/bearing model was represented by the generalized (modal) parameters of the first lateral mode, with the rotational character of the fluid force taken into account.

  15. Experiments in Support of Pressure Enhanced Penetration with Shaped Charge Perforators

    SciTech Connect

    Glenn, L.A.; Chase, J.B.; Barker, J.; Leidel, D.J.

    1999-11-01

    Computational analysis demonstrated that the penetration of a shaped charge could be substantially enhanced by imploding the liner in a high pressure light gas atmosphere. The gas pressure helps confine the jet on the axis of penetration in the latter stages of formation. A light gas, such as helium or hydrogen, is required in order to keep the gas density low enough so as not to inhibit liner collapse. These results have now been confirmed by experiment. Identical 5-foot long guns, each containing 37 perforators at a shot density of 12 SPF, were inserted in two API Section 1 concrete targets, poured on the same day and cured for the same period. One of the guns was fired with interior ambient (0.1 MPa) air pressure and the other with helium at 13.8 MPa (2,000 psia). The average penetration from the 37 perforations with the helium system increased 40.3% over that obtained with the conventional system.

  16. Non-invasive ventilation with neurally adjusted ventilatory assist in newborns.

    PubMed

    Stein, Howard; Beck, Jennifer; Dunn, Michael

    2016-06-01

    Neurally adjusted ventilatory assist (NAVA) is a mode of ventilation in which both the timing and degree of ventilatory assist are controlled by the patient. Since NAVA uses the diaphragm electrical activity (Edi) as the controller signal, it is possible to deliver synchronized non-invasive NAVA (NIV-NAVA) regardless of leaks and to monitor continuously patient respiratory pattern and drive. Advantages of NIV-NAVA over conventional modes include improved patient-ventilator interaction, reliable respiratory monitoring and self-regulation of respiratory support. In theory, these characteristics make NIV-NAVA an ideal mode to provide effective, appropriate non-invasive support to newborns with respiratory insufficiency. NIV-NAVA has been successfully used clinically in neonates as a mode of ventilation to prevent intubation, to allow early extubation, and as a novel way to deliver nasal continuous positive airway pressure. The use of NAVA in neonates is described with an emphasis on studies and clinical experience with NIV-NAVA. PMID:26899957

  17. Noninvasive ventilation in a child affected by achondroplasia respiratory difficulty syndrome.

    PubMed

    Ottonello, Giancarlo; Villa, Giovanna; Moscatelli, Andrea; Diana, Maria Cristina; Pavanello, Marco

    2007-01-01

    Achondroplasia can result in respiratory difficulty in early infancy, from anatomical abnormalities such as mid-facial hypoplasia and/or adenotonsillar hypertrophy, leading to obstructive apnea, or to pathophysiological changes occurring in nasopharyngeal or glossal muscle tone, related to neurological abnormalities (foramen magnum and/or hypoglossal canal problems, hydrocephalus), leading to central apnea. More often, the two respiratory components (central and obstructive) are both evident in mixed apnea. Polysomnographic recording should be used during preoperative and postoperative assessment of achondroplastic children and in the subsequent follow-up to assess the adequacy of continuing home respiratory support, including supplemental oxygen, bilevel positive airway pressure, or assisted ventilation. PMID:17184438

  18. Unwinding Au(+)···Au(+) Bonded Filaments in Ligand-Supported Gold(I) Polymer under Pressure.

    PubMed

    Paliwoda, Damian; Wawrzyniak, Paulina; Katrusiak, Andrzej

    2014-07-01

    The ultimately thin single-strand gold filaments, of Au(+)···Au(+) bonded gold(I) diethyldithiocarbamate polymer, AuEt2DTC, can be transformed depending on pressure and solvate contents. When synthesized in the presence of CH2Cl2, it crystallizes into a tetragonal AuEt2DTC·xCH2Cl2 phase α with ligand-supported and unsupported Au(+)···Au(+) bonded filaments modulated into molecular Au8-pitch helices. Low contents of CH2Cl2 favors the β phase of significantly reduced volume and orthorhombic space group Fddd. The α-AuEt2DTC·xCH2Cl2 crystal exhibits a highly unusual negative-area compressibility, due to the spring-like compression of helices. Above 0.05 GPa, the crystal transforms to phase β, where the Au16-pitch helices partly unwind their turns, which relaxes the tension generated by external pressure between neighboring helices of the opposite handedness. This is a unique observation of atomic-scale helical filaments transformation, which otherwise is a universal process analogous to the helix reversal between DNA forms B and Z, and in macroscopic world it is similar to nonperiodic unwind kinks in grapevine tendrils and telephone cords. Pressure also reduces the differences between the ligand-supported and unsupported Au(+)···Au(+) bonds. PMID:26279531

  19. A multicentre, randomised controlled, non-inferiority trial, comparing high flow therapy with nasal continuous positive airway pressure as primary support for preterm infants with respiratory distress (the HIPSTER trial): study protocol

    PubMed Central

    Roberts, Calum T; Owen, Louise S; Manley, Brett J; Donath, Susan M; Davis, Peter G

    2015-01-01

    Introduction High flow (HF) therapy is an increasingly popular mode of non-invasive respiratory support for preterm infants. While there is now evidence to support the use of HF to reduce extubation failure, there have been no appropriately designed and powered studies to assess the use of HF as primary respiratory support soon after birth. Our hypothesis is that HF is non-inferior to the standard treatment—nasal continuous positive airway pressure (NCPAP)— as primary respiratory support for preterm infants. Methods and analysis The HIPSTER trial is an unblinded, international, multicentre, randomised, non-inferiority trial. Eligible infants are preterm infants of 28–36+6 weeks’ gestational age (GA) who require primary non-invasive respiratory support for respiratory distress in the first 24 h of life. Infants are randomised to treatment with either HF or NCPAP. The primary outcome is treatment failure within 72 h after randomisation, as determined by objective oxygenation, blood gas, and apnoea criteria, or the need for urgent intubation and mechanical ventilation. Secondary outcomes include the incidence of intubation, pneumothorax, bronchopulmonary dysplasia, nasal trauma, costs associated with hospital care and parental stress. With a specified non-inferiority margin of 10%, using a two-sided 95% CI and 90% power, the study requires 375 infants per group (total 750 infants). Ethics and dissemination Ethical approval has been granted by the relevant human research ethics committees at The Royal Women's Hospital (13/12), The Royal Children's Hospital (33144A), The Mercy Hospital for Women (R13/34), and the South-Eastern Norway Regional Health Authority (2013/1657). The trial is currently recruiting at 9 centres in Australia and Norway. The trial results will be published in peer-reviewed international journals, and presented at national and international conferences. Trial registration number Australian New Zealand Clinical Trials Registry ID: ACTRN

  20. Measuring Wind Ventilation of Dense Surface Snow

    NASA Astrophysics Data System (ADS)

    Drake, S. A.; Huwald, H.; Selker, J. S.; Higgins, C. W.; Lehning, M.; Thomas, C. K.

    2014-12-01

    Wind ventilation enhances exposure of suspended, canopy-captured and corniced snow to subsaturated air and can significantly increase sublimation rate. Although sublimation rate may be high for highly ventilated snow this snow regime represents a small fraction snow that resides in a basin potentially minimizing its influence on snow mass balance. In contrast, the vast majority of a seasonal snowpack typically resides as poorly ventilated surface snow. The sublimation rate of surface snow is often locally so small as to defy direct measurement but regionally pervasive enough that the integrated mass loss of frozen water across a basin may be significant on a seasonal basis. In a warming climate, sublimation rate increases even in subfreezing conditions because the equilibrium water vapor pressure over ice increases exponentially with temperature. To better understand the process of wintertime surface snow sublimation we need to quantify the depth to which turbulent and topographically driven pressure perturbations effect air exchange within the snowpack. Hypothetically, this active layer depth increases the effective ventilated snow surface area, enhancing sublimation above that given by a plane, impermeable snow surface. We designed and performed a novel set of field experiments at two sites in the Oregon Cascades during the 2014 winter season to examine the spectral attenuation of pressure perturbations with depth for dense snow as a function of turbulence intensity and snow permeability. We mounted a Campbell Scientific Irgason Integrated CO2 and H2O Open Path Gas Analyzer and 3-D Sonic Anemometer one meter above the snow to capture mean and turbulent wind forcing and placed outlets of four high precision ParoScientific 216B-102 pressure transducers at different depths to measure the depth-dependent pressure response to wind forcing. A GPS antenna captured data acquisition time with sufficient precision to synchronize a Campbell Scientific CR-3000 acquiring

  1. ASHRAE and residential ventilation

    SciTech Connect

    Sherman, Max H.

    2003-10-01

    In the last quarter of a century, the western world has become increasingly aware of environmental threats to health and safety. During this period, people psychologically retreated away from outdoors hazards such as pesticides, smog, lead, oil spills, and dioxin to the seeming security of their homes. However, the indoor environment may not be healthier than the outdoor environment, as has become more apparent over the past few years with issues such as mold, formaldehyde, and sick-building syndrome. While the built human environment has changed substantially over the past 10,000 years, human biology has not; poor indoor air quality creates health risks and can be uncomfortable. The human race has found, over time, that it is essential to manage the indoor environments of their homes. ASHRAE has long been in the business of ventilation, but most of the focus of that effort has been in the area of commercial and institutional buildings. Residential ventilation was traditionally not a major concern because it was felt that, between operable windows and envelope leakage, people were getting enough outside air in their homes. In the quarter of a century since the first oil shock, houses have gotten much more energy efficient. At the same time, the kinds of materials and functions in houses changed in character in response to people's needs. People became more environmentally conscious and aware not only about the resources they were consuming but about the environment in which they lived. All of these factors contributed to an increasing level of public concern about residential indoor air quality and ventilation. Where once there was an easy feeling about the residential indoor environment, there is now a desire to define levels of acceptability and performance. Many institutions--both public and private--have interests in Indoor Air Quality (IAQ), but ASHRAE, as the professional society that has had ventilation as part of its mission for over 100 years, is the

  2. Circulatory effects of fast ventilator rates in preterm infants.

    PubMed Central

    Fenton, A C; Field, D J; Woods, K L; Evans, D H; Levene, M I

    1990-01-01

    High frequency positive pressure ventilation has been suggested to result in a lower incidence of respiratory complications in preterm infants with idiopathic respiratory distress syndrome compared with ventilation at conventional rates. A possible disadvantage is compromise of the infant's cardiovascular condition secondary to inadvertent positive end expiratory pressure (PEEP). In a group of 20 such infants treated with high frequency positive pressure ventilation (rates of up to 100/minute) and analysed, changes in arterial blood pressure and cerebral blood flow velocity were largely influenced by changes in arterial blood gases, and no effect could be attributed to inadvertent PEEP. In addition, the observed fall in both arterial carbon dioxide and oxygen tensions could be readily predicted for theoretical reasons. Under certain conditions at the fastest rates used, cerebral blood flow velocity was significantly influenced by changes in blood pressure, which may indicate impaired cerebrovascular regulation. Though other factors (such as the severity of the infants' illness or the use of paralysis) may have been responsible for this apparent blood pressure passivity, the role of high frequency positive pressure ventilation in such infants warrants further study. PMID:2117423

  3. Health and Safety Benefits of Small Pressurized Suitport Rovers as EVA Surface Support Vehicles

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael L.; Abercromby, Andrew F. J.

    2008-01-01

    Pressurized safe-haven providing SPE protection and decompression sickness (DCS) treatment capabilities within 20 mins at all times. Up to 50% reduction in time spent in EVA suits (vs. Unpressurized Rovers) for equal or greater Boots-on-Surface EVA exploration time. Reduces suit-induced trauma and provides improved options for nutrition, hydration, and waste-management. Time spent inside SPR during long translations may be spent performing resistive and cardiovascular exercise. Multiple shorter EVAs versus single 8 hr EVAs increases DCS safety and decreases prebreathe requirements. SPRs also offer many potential operational, engineering and exploration benefits not addressed here.

  4. Impact of radiation embrittlement on integrity of pressure vessel supports for two PWR plants

    SciTech Connect

    Cheverton, R.D.; Pennell, W.E.; Robinson, G.C.; Nanstad, R.K.

    1989-01-01

    Recent data from the HFIR vessel surveillance program indicate a substantial radiation embrittlement rate effect at low irradiation temperatures (/approximately/120/degree/F) for A212-B, A350-LF3, A105-II, and corresponding welds. PWR vessel supports are fabricated of similar materials and are subjected to the same low temperatures and fast neutron fluxes (10/sup 8/ to 10/sup 9/ neutrons/cm/sup 2//center dot/s, E > 1.0 MeV) as those in the HFIR vessel. Thus, the embrittlement rate of these structures may be greater than previously anticipated. A study sponsored by the NRC is under way at ORNL to determine the impact of the rate effect on PWR vessel-support life expectancy. The scope includes the interpretation and application of the HFIR data, a survey of all light-water-reactor vessel support designs, and a structural and fracture-mechanics analysis of the supports for two specific PWR plants of particular interest with regard to a potential for support failure as a result of propagation of flaws. Calculations performed thus far indicate best-estimate critical flaw sizes, corresponding to 32 EFPY, of /approximately/0.2 in. for one plant and /approximately/0.4 in. for the other. These flaw sizes are small enough to be of concern. However, it appears that low-cycle fatigue is not a viable mechanism for creation of flaws of this size, and thus, presumably, such flaws would have to exist at the time of fabrication. 59 refs., 128 figs., 49 tabs.

  5. An approach to ventilation in acute respiratory distress syndrome

    PubMed Central

    Houston, Patricia

    2000-01-01

    Appropriate management of patients with acute respiratory distress syndrome (ARDS) represents a challenge for physicians working in the critical care environment. Significant advances have been made in understanding the pathophysiology of ARDS. There is also an increasing appreciation of the role of ventilator-induced lung injury (VILI). VILI is most likely related to several different aspects of ventilator management: barotrauma due to high peak airway pressures, lung overdistension or volutrauma due to high transpulmonary pressures, alveolar membrane damage due to insufficient positive end-expiratory pressure levels and oxygen-related cell toxicity. Various lung protective strategies have been suggested to minimize the damage caused by conventional modes of ventilation. These include the use of pressure- and volume-limited ventilation, the use of the prone position in the management of ARDS, and extracorporeal methods of oxygen delivery and carbon dioxide removal. Although the death rate resulting from ARDS has been declining over the past 10 years, there is no evidence that any specific treatment or change in approach to ventilation is the cause of this impro