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PubMedDate not supplied

Rescue from pediatric ECMO with prolonged hybrid intratracheal pulmonary ventilation. A technique for reducing dead space ventilation and preventing ventilator induced lung injury.

Hybrid intratracheal pulmonary ventilation (h-ITPV) is a continuous flow ventilatory technique that uses a "reverse thruster" catheter to redirect the flow of gas away from the carina. We report here the use of h-ITPV in a pediatric patient with acute sickle cell chest syndrome who required venoarterial ECMO support because of refractory hypoxemic respiratory failure. Her ECMO course was complicated by air leaks, coagulopathy, cardiac tamponade, and necrotizing tracheobronchitis. She could be weaned from ECMO only by maintaining high pressure conventional ventilatory support. To prevent ventilator induced barotrauma, we initiated h-ITPV and weaned her from ECMO bypass. After 12 days of h-ITPV, with tidal volumes of 2-3 ml/kg at carinal peak inspiratory pressures of 25-30 cm H2O, the air leaks ceased and h-ITPV was discontinued. Dead space ventilation fraction (VD/VT) as low as 0.29 was achieved with this technique. Post-h-ITPV bronchoscopy displayed a dramatic resolution of the necrotizing tracheobronchitis. The patient survived and was discharged from the hospital. We conclude that the use of hybrid ITPV may facilitate weaning from ECMO to low pressure conventional ventilation and prevent the development of pulmonary barotrauma.

Acid-Base Equilibrium↗
PubMedDate not supplied

Comparison of bag-valve-mask, manually triggered ventilator, and automated ventilator devices used while ventilating a nonintubated mannikin model.

OBJECTIVE: To determine whether there were differences in tidal volume (Vt), minute volume (MV), average mask leak per breath (ML), gastric insufflation (GI), and peak airway pressure (PAP) when ventilating a nonintubated mannikin with a bag-valve-mask (BV), manually triggered ventilator (MTV), and automated ventilator (AV). The authors' hypothesis was that there would be no differences among the devices for any of these variables. METHODS: This was a prospective in-vitro experimental model. A convenience sample of 19 emergency medical technicians (EMTs) ventilated a nonintubated mannikin-mechanical test lung model with the BV, MTV (flow rate 40 L/min; pressure relief 55 cm H2O), and AV (800 mL/breath; rate 12). Each subject, blinded to volume and pressure gauges, used each device for 2 minutes at both normal (0.1 cm H2O) and poor (0.04 cm H2O) compliances. Vt, MV, GI, and PAP were measured directly and ML was calculated. A survey was issued to the EMTs who participated in the study. Data were analyzed with repeated-measures ANOVA and the Bonferroni-Dunn multiple comparison test with alpha set at 0.05. RESULTS: At the normal compliance, PAP was higher for the BV than the MTV (p = 0.0001) and AV (p < 0.0001). MV was also greater with the BV than with the AV (p = 0.001). PAP was also higher at the poor compliance with the BV than with the MTV and AV (p = 0.008 and 0.013, respectively). The BV had a higher GI at this compliance (p < 0.0001) and a higher ML than the AV (p = 0.002). CONCLUSION: All three devices delivered similar volumes when used by EMTs, but the BV was associated with higher PAP, ML, and GI.

Adult↗
PubMed2003

Open-lung protective ventilation with pressure control ventilation, high-frequency oscillation, and intratracheal pulmonary ventilation results in similar gas exchange, hemodynamics, and lung mechanics.

BACKGROUND: Pressure control ventilation (PCV), high-frequency oscillation (HFO), and intratracheal pulmonary ventilation (ITPV) may all be used to provide lung protective ventilation in acute respiratory distress syndrome, but the specific approach that is optimal remains controversial. METHODS: Saline lavage was used to produce acute respiratory distress syndrome in 21 sheep randomly assigned to receive PCV, HFO, or ITPV as follows: positive end-expiratory pressure (PCV and ITPV) and mean airway pressure (HFO) were set in a pressure-decreasing manner after lung recruitment that achieved a ratio of Pao2/Fio2 > 400 mmHg. Respiratory rates were 30 breaths/min, 120 breaths/min, and 8 Hz, respectively, for PCV, ITPV, and HFO. Eucapnia was targeted with peak carinal pressure of no more than 35 cm H2O. Animals were then ventilated for 4 h. RESULTS: There were no differences among groups in gas exchange, lung mechanics, or hemodynamics. Tidal volume (PCV, 8.9 +/- 2.1 ml/kg; ITPV, 2.7 +/- 0.8 ml/kg; HFO, approximately 2.0 ml/kg) and peak carinal pressure (PCV, 30.6 +/- 2.6 cm H2O; ITPV, 22.3 +/- 4.8 cm H2O; HFO, approximately 24.3 cm H2O) were higher in PCV. Pilot histologic data showed greater interstitial hemorrhage and alveolar septal expansion in PCV than in HFO or ITPV. CONCLUSION: These data indicate that HFO, ITPV, and PCV when applied with an open-lung protective ventilatory strategy results in the same gas exchange, lung mechanics, and hemodynamic response, but pilot data indicate that lung injury may be greater with PCV.

Air Pressure↗
PubMed2000

Effects of prolonged partial liquid ventilation, high frequency ventilation and conventional ventilation on gas exchange and lung pathology in newborn surfactant-depleted piglets.

Partial liquid ventilation (PLV) improves oxygenation in various animal models of respiratory insufficiency. The aim of this study was to compare the effects of conventional ventilation (CV), high frequency oscillatory ventilation (HFOV), and PLV combined with CV or HFOV on gas exchange and histopathology. Thirty anaesthetised newborn piglets (mean weight 1.94 kg, age 1-3 days) were randomized in five groups of six animals: CV, CV + surfactant (S), HFOV+S, PLV/CV, and PLV/HFOV. Thirty min after lung injury had been induced with repeated saline lavage, specific ventilatory treatment was initiated. Three animals of the CV group died within the 24 h study period, whereas none died in any of the other groups. The oxygenation index (OI) and the PaO2/FIO2 ratio improved significantly within 30 min in all groups, but not in the CV group. After 24 h all oxygenation parameters were better in the PLV groups than in CV or CV+S (P < 0.05). No differences in gas exchange were noted between HFOV+S and PLV/CV. The combination of PLV with HFOV led to an increased PaO2/FIO2 ratio when compared with PLV/CV and with HFOV+S (P < 0.05). All PLV treated animals had significantly less lung injury in the upper and lower lobes compared with gas-ventilated animals by histologic semi-quantitative lung injury score (P < 0.01) and in the lower lobes by morphometry (P < 0.001). In conclusion, HFOV+S and PLV either with CV or HFOV are effective techniques to provide adequate gas exchange in S-deficient lungs compared with CV with and without S. However, lung injury was significantly improved in both PLV treated groups compared with HFOV+S and the CV groups.

Animals↗
PubMed1990

[Optimization of ventilation in anesthesia. 6. Quantitative registration of ventilation perfusion disorders during ventilation].

The ventilation perfusion perturbations which were registered during narcosis ventilation with different ventilation patterns were investigated by means of time series analysis. It was shown that the time progress of the parameter PaO2 can be approximated by a linear equation in the considered time interval. The coefficient of the linear term of this equation describes the degree of the ventilation perfusion perturbations. The prediction made by this evaluation was confirmed by experimental data.

Humans↗
PubMed1993

[Long-term artificial ventilation by nasal intermittent positive pressure ventilation; 6 cases of domiciliary assisted ventilation].

Six patients with chronic respiratory failure associated with hypercapnia were treated with nasal intermittent positive pressure ventilation (NIPPV) at home. NIPPV was delivered via a custom molded nasal interface described by McDermott. The patients consisted of one patient with kyphoscoliosis, three with Tb-sequela, one with COPD, and one with neuromuscular disease. Each patient had been treated with oxygen therapy until assisted ventilation was initiated because of CO2 retention. NIPPV was administered using a volume cycled flow generator set to deliver a minute volume such that PaCO2 was maintained between 35 and 45 Torr on NIPPV trial performed during wakefulness under the condition of no leakage from the mask. Supplementary oxygen was added so that oxygen saturation was maintained above 90 percent during more than 95% of nighttime NIPPV. Arterial blood gas tensions during daytime spontaneous breathing showed an improvement (PaCO2 68.3 +/- 7.2 Torr, PaO2 70.4 +/- 15.5 Torr, SaO2 91.6 +/- 4.3% before treatment; PaCO2 55.8 +/- 4.7 Torr, PaO2 87.5 +/- 16.5 Torr, SaO2 95.5 +/- 1.7% on treatment, mean +/- SD). The duration of NIPPV at home ranged from 2 to 24 months (11.7 +/- 6.8), and there was no hospitalization due to exacerbation during this period. In conclusion, NIPPV via a custom molded mask is simple, noninvasive, and suitable for the provision of long-term and domiciliary assisted ventilation.

Adult↗
PubMed1983

Ventilator-induced barotrauma in controlled mechanical ventilation versus intermittent mandatory ventilation.

Retrospective analysis of pulmonary barotrauma incidence in 292 patients ventilated greater than or equal to 24 h was conducted. From 1971-1973, 156 patients with acute respiratory insufficiency were managed with controlled mechanical ventilation (CMV) and PEEP. During 1973-1976, 136 patients were supported with IMV and CPAP. Despite higher mean peak and end-expiratory airway pressure, the IMV-CPAP group exhibited a significantly lower incidence of ventilator-induced barotrauma; 7% vs 22% (p less than 0.01). We suspect the difference is related to fewer mechanical breaths with IMV and not to the level of end-expiratory pressure employed.

Barotrauma↗
PubMed1994

Respiratory and haemodynamic effects of conventional volume controlled PEEP ventilation, pressure regulated volume controlled ventilation and low frequency positive pressure ventilation with extracorporeal carbon dioxide removal in pigs with acute ARDS.

The purpose of this study was to evaluate whether any benefit of low frequency positive pressure ventilation with extracorporeal carbon dioxide removal (LFPPV-ECCO2R) existed over either volume controlled ventilation (VCV) with measured best-PEEP or pressure regulated volume controlled ventilation (PRVCV) with an inspiration/expiration (I/E) ratio of 4:1, with respect to arterial oxygenation, lung mechanics and haemodynamics, in acute respiratory failure. Fifteen adult pigs were used for the study. Respiratory failure was induced by surfactant depletion by repeated lung lavage. The different therapeutic approaches were applied randomly to each pig for 1 h. Measurements of gas exchange, airway pressures and haemodynamics were performed during ventilatory and haemodynamic steady state. Paco2 was kept constant in all modes. At almost similar total-PEEP, Pao2 values were significantly higher with LFPPV-ECCO2R compared to VCV with best-PEEP. Peak inspiratory pressure (PIP) and intrapulmonary pressure amplitude defined as the difference between PIP and total-PEEP were significantly lower with PRVCV and LFPPV-ECCO2R compared to VCV with best-PEEP. There was no significant difference between the modes concerning cardiocirculatory parameters. PRVCV with I/E ratio of 4:1 and LFPPV-ECCO2R proved to be better modes to achieve better gas exchange and lower PIP at lower intrapulmonary pressure amplitudes. It is concluded that PRVCV is an adequate form of treatment under these experimental conditions imitating acute respiratory failure, without necessitating other invasive measures.

Acute Disease↗
PubMed1982

Mechanical ventilation in fiberoptic-bronchoscopy: comparison between high frequency positive pressure ventilation and normal frequency positive pressure ventilation.

High frequency positive pressure ventilation (HFPPV) was compared with normal frequency positive pressure ventilation (NFPPV) during diagnostic fiberoptic-bronchoscopy. HFPPV was achieved by a simple modification of the Minivent, and gave satisfactory alveolar ventilation and oxygenation. In all 11 patients and over periods of at least 40 min, HFPPV gave normal PaCO2 and high levels of PAO2. Arterial blood pressures were higher and the airway pressures were lower than during NFPPV.

Adult↗
PubMed2003

[Mechanical ventilation in pediatrics (III). Weaning, complications and other types of ventilation. Compications of mechanical ventilation].

Mechanical ventilation can produce multiple complications. The most important acute complications are mechanical problems (respirator failure, problems with the connections and circuit, incorrect parameters or alarms), problems in the airway (disconnection, extubation, mal-positioning of the endotracheal tube, leaks, nose erosions, obstruction of the endotracheal tube due to secretions or kinking, mainstem bronchus intubation, bronchospasm, postextubation croup), pulmonary complications (ventilator-induced lung injury with barotrauma, volutrauma and biotrauma), hemodynamic complications, nosocomial infections (tracheobronchitis, pneumonia, otitis, sinusitis), failure of adjustment of the respirator to the patient, and nutritional complications. The most important chronic problems are subglottal stenosis, chronic pulmonary injury, and psychological alterations.

Barotrauma↗
PubMed1996

[Intermittent self-ventilation in neuromuscular diseases. Comparison of lung function parameters in ventilated and non-ventilated patients].

BACKGROUND: Based on neuromuscular-disease patients in our case, we investigate the possibility of elaborating criteria by which to judge when home intermittent mechanical ventilation should be commenced and to access its consequences over an extended period. PATIENTS AND METHODS: Out of 24 patients with neuromuscular diseases (6 female, 18 male, mean age 32 years), 14 were treated with IPPV. They were suffering from hypercapnic respiratory failure with heavy sleep disruption and corresponding daily symptoms. RESULTS: The aim was to calculate significant examination parameters to facilitate indication for IPPV. The clinical situation of patients dependent on respiratory support improved under IPPV. We witnessed a "ventilation-saving effect" and--despite progression of the basic disease within the monitoring period--no deterioration of the blood-gas situation. CONCLUSIONS: It is possible to elaborate criteria for the indication of IPPV based on our group of neuromuscular-disease patients.

Adolescent↗
PubMed2000

Synchronized mechanical ventilation for respiratory support in newborn infants.

BACKGROUND: During synchronous ventilation, positive pressure ventilation and spontaneous inspiration coincide. Thus, if synchronous ventilation is provoked, it is likely that adequate gas exchange should be achieved at lower peak pressures, reducing barotrauma and hence airleak and chronic lung disease. Synchronous ventilation can be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient assisted ventilation. OBJECTIVES: To compare (i) the efficacy of synchronized mechanical ventilation, delivered as high frequency positive pressure ventilation or triggered ventilation (patient triggered ventilation (PTV) or synchronous intermittent mandatory ventilation (SIMV)) with conventional ventilation (ii) different types of triggered ventilation SEARCH STRATEGY: Searches were made of the Oxford Database of Perinatal Trials, Medline (MESH terms: mechanical ventilation; triggered ventilation; newborn infant); previous reviews, abstracts, symposia proceedings, hand searching of journals in the English language and contacting expert informants. SELECTION CRITERIA: Randomized or quasi randomized clinical trials comparing synchronized ventilation delivered as high frequency positive pressure ventilation (HFPPV) or triggered ventilation (PTV/SIMV) to conventional ventilation (CMV) in neonates. Randomized trials comparing different triggered ventilation modes (PTV and SIMV) in neonates. DATA COLLECTION AND ANALYSIS: Data regarding clinical outcomes including mortality, airleaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intracerebral haemorrhage (grades 3 and 4), chronic lung disease (oxygen dependency beyond 28 days) and duration of weaning/ventilation. Data subdivided into three groups: (i) HFPPV vs CMV; (ii) PTV/SIMV vs CMV; (iii) PTV vs SIMV. Data analysis was conducted according to the standards of the Neonatal Cochrane Review Group. MAIN RESULTS: The meta-analysis demonstrates that HFPPV compared to CMV was associated with a reduction in the risk of airleak (typical relative risk 0.68, 95% CI 0.55, 0.68). PTV/SIMV compared to CMV was associated with a shorter duration of ventilation (Weighted mean difference -45.2 hours, 95% CI -78.3, -12.1). PTV compared to SIMV was associated with a trend to a shorter duration of weaning (Weighted mean difference 42.4 hours, 95% CI -9.6,94.4). No disadvantage to HFPPV or triggered ventilation was noted regarding other outcomes. REVIEWER'S CONCLUSIONS: Compared to conventional ventilation, benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in airleak and a shorter duration of ventilation respectively. In none of the trials was complex respiratory monitoring undertaken and thus it is not possible to conclude that the mechanism of producing those benefits is by provocation of synchronized ventilation. Further trials are needed to determine whether synchronized ventilation is associated with a reduction in chronic oxygen dependency.

Humans↗
PubMed1997

[Cardiopulmonary effects of two modes of mechanical ventilation in dogs with and without acute lung injury-comparison of pressure regulated biphasic airway presure ventilation and intermittent positive pressure ventilation].

OBJECTIVE: To compare the cardiopulmonary effect of pressure regulated biphasic airway pressure (BiPAP) and intermittent positive pressure ventilation (IPPV). METHOD: Airway pressure, hemodynamics and blood gases were measured during the two ventilatory modalities with 0, 0.5, 1 kPa external end-expiratory pressure (EEP) in dogs with and without oleic acid-induced lung injury. RESULTS: No matter whether there is lung injury, airway pressure during BiPAP is lower compared with IPPV, but there is no difference in cardiac output. In dogs with lung injury, PaO2 during BiPAP is higher than that during IPPV. CONCLUSIONS: Compared with IPPV, BiPAP effected a decrease in airway pressure, and PaO2 was improved in dogs with lung injury, although the cardiac output was not increased.

Animals↗
PubMed1993

Pressure-controlled ventilation versus controlled mechanical ventilation with decelerating inspiratory flow.

OBJECTIVE: To ascertain whether pressure-controlled ventilation offers any advantage with respect to conventional controlled mechanical ventilation with decelerating flow. DESIGN: Prospective, comparative study. SETTING: Intensive care unit. PATIENTS: Eleven consecutive critically ill adult patients. MEASUREMENTS AND MAIN RESULTS: Study of respiratory mechanics and arterial blood gases after 30 mins of pressure-controlled ventilation. Repetition of the same measurements after 30 mins of controlled mechanical ventilation with decelerating flow waveform, with equal tidal volumes, using a commercially available mechanical ventilator. Student's t-test for paired comparisons. A lesser maximum inspiratory flow rate was required for pressure-controlled ventilation (55.7 +/- 16 L/sec) than for controlled mechanical ventilation (72 +/- 2 L/sec) (p < .001). Nevertheless, the peak pressures measured in the orotracheal tubes of the patients were higher in pressure-controlled ventilation (20.4 +/- 3.5 cm H2O) than in controlled mechanical ventilation (18.4 +/- 4.8 cm H2O) (p < .05). This model measured pressure in the inspiratory line, providing erroneous information regarding the behavior of pressures in the airway. The peak pressure measured by the ventilator was significantly higher in controlled mechanical ventilation than in pressure-controlled ventilation and was, in addition, reached at initiation of inspiration in ten of 11 patients with controlled mechanical ventilation, while peak pressure measured in the orotracheal tube was invariably reached at the end of the inspiration, both in pressure-controlled ventilation and controlled mechanical ventilation. The rest of the parameters analyzed, including end-inspiratory pressure, mean pressure, intrinsic positive end-expiratory pressure, and arterial blood gases, showed no differences. The difference between quasi-static compliances almost reached statistical significance (72 +/- 25.4 mL/cm H2O in pressure-controlled ventilation vs. 68.8 +/- 24.3 mL/cm H2O in controlled mechanical ventilation; p = .052). CONCLUSIONS: Our study failed to demonstrate any important difference between pressure-controlled ventilation and controlled mechanical ventilation with decelerating inspiratory flow waveform. The differences in the airway pressures detected by the ventilator are spurious and are due to the place (inspiratory line) where these pressures were measured. The difference between the peak pressure measured in the orotracheal tube has statistical, but not clinical, value and is lower in controlled mechanical ventilation. Based on the limited number of variables we studied and unless the tendency indicated in the quasi-static compliance is demonstrated in the future, we do not believe that pressure-controlled ventilation contributes any uniqueness to the theory or practice of mechanical ventilation.

Adolescent↗
PubMed2006

Performance characteristics of five new anesthesia ventilators and four intensive care ventilators in pressure-support mode: a comparative bench study.

BACKGROUND: During the past few years, many manufacturers have introduced new modes of ventilation in anesthesia ventilators, especially partial-pressure modalities. The current bench test study was designed to compare triggering and pressurization of five new anesthesia ventilators with four intensive care unit ventilators. METHODS: Ventilators were connected to a two-compartment lung model. One compartment was driven by an intensive care unit ventilator to mimic "patient" inspiratory effort, whereas the other was connected to the tested ventilator. The settings of ventilators were positive end-expiratory pressures of 0 and 5 cm H2O, and pressure-support ventilation levels of 10, 15, and 20 cm H2O with normal and high "patient" inspiratory effort. For the anesthesia ventilators, all the measurements were obtained for a low (1 l/min) and a high (10 l/min) fresh gas flow. Triggering delay, triggering workload, and pressurization at 300 and 500 ms were analyzed. RESULTS: For the five tested anesthesia ventilators, the pressure-support ventilation modality functioned correctly. For inspiratory triggering, the three most recent anesthesia machines (Fabius, Drägerwerk AG, Lübeck, Germany; Primus, Drägerwerk AG; and Avance, GE-Datex-Ohemda, Munchen, Germany) had a triggering delay of less than 100 ms, which is considered clinically satisfactory and is comparable to intensive care unit machines. The use of positive end-expiratory pressure modified the quality of delivered pressure support for two anesthesia ventilators (Kion, Siemens AG, Munich, Germany; and Felix, Taema, Antony, France). Three of the five anesthesia ventilators exhibited pressure-support ventilation performance characteristics comparable to those of the intensive care unit machines. Increasing fresh gas flow (1 to 10 l/min) in the internal circuit did not influence the pressure-support ventilation performance of the anesthesia ventilators. CONCLUSION: Regarding trigger sensitivity and the system's ability to meet inspiratory flow during pressure-supported breaths, the most recent anesthesia ventilators have comparable performances of recent-generation intensive care unit ventilators.

Anesthesia, Inhalation↗
PubMed2001

An evaluation of ventilator reliability: a multivariate, failure time analysis of 5 common ventilator brands.

INTRODUCTION: Mechanical ventilator failures expose patients to unacceptable risks and are expensive. By identifying factors that correlate with the amount of time between consecutive ventilator failures, we might reduce patient risk, save money, and shed light on a number of important questions concerning whether reliability changes as a function of time. OBJECTIVE: Investigate the correlation between several explanatory variables and the time between consecutive ventilator failures and address the following questions: (1) Are ventilators as safe and reliable following repairs as they were before failing? (2) Does reliability change significantly as a ventilator is used or ages? (3) Does a hospital's particular operating environment play a role in ventilator reliability? (4) Are ventilator service contracts worth the money? METHODS: A retrospective review was conducted using repair and maintenance records from 2 hospitals: a 570-bed teaching hospital and a 410-bed local community hospital. Records were examined from a total of 66 individual ventilators, of 5 different brands, used between July 1, 1991, and January 3, 2001. The ventilators included 13 Tyco-Mallinckrodt Infant Star, 10 Bird VIP, 11 Bird 6400ST, 16 Bird 8400STi, and 16 Tyco-Mallinckrodt 7200ae. The dependent variable was the operating time between or before unexpected mechanical failures; this was determined by the difference between hours logged on the ventilator hour meter at the time of failure and that recorded when the study began, or when the ventilator was new. Thereafter (when applicable), the time before failure was the difference in hours at consecutive failures. Seven independent explanatory covariates were selected and analyzed as potential correlates with time between failures. Another independent variable, the site of ventilator use (community or teaching hospital), was also tested for significance. Data were analyzed using the Cox proportional hazard model, the multiple-groups survival statistic, and the Cox-Mantel test. RESULTS: In 2,567,365 hours of ventilator operation, 290 observations were recorded (226 failures and 64 censored observations). Two of the 7 covariates were judged time-dependent, excluded from the Cox model, and evaluated using other techniques. Of the 5 remaining covariates, 2 were significantly related to reliability, both indirectly. There was no difference in reliability, regardless of how many times a ventilator had been previously repaired, but hospital environment did significantly affect reliability. CONCLUSIONS: Ventilator reliability depends on a number of factors. This study indicates that, on average, ventilator reliability improves the more a ventilator is used and the longer the brand has been commercially available. The number of previous ventilator repairs did not affect reliability, but the hospital environment did. These data, if validated, should help to enhance our understanding of ventilator reliability and could eventually have profound economic and safety implications as well.

Contract Services↗