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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 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

  9. 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

  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

    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 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

  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. 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

  8. 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

  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. 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

  16. 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

  17. 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

  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 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

  1. 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

  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 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

  14. 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

  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. 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

  4. [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

  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. 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

  1. 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

  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. 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

  16. 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).

  17. 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).

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  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. 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

  6. 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

  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

    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 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

  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

    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

  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 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

  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. 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 ...

  9. 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

  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. 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

  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. 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.

  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. 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

  4. 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

  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 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

  2. 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

  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

    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

  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 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