Hemodynamic effects of partial liquid ventilation with perfluorocarbon in acute lung injury

Objective: To assess the effect of partial liquid ventilation with perfluorocarbons on hemodynamics and gas exchange in large pigs with induced acute lung injury (ALI). Design: Randomized, prospective, double-control, experimental study. Setting: Experimental intensive care unit of a university. Materials: Eighteen large pigs (50±5 kg body weight) with an average anterior posterior thoracic diameter of 24 cm and induced acute lung injury. Interventions: All animals were surfactant depleted by lung lavage to a PaO2 below 100 mmHg and randomized to receive either perflubron (n=6) or saline (n=6) in five intratracheal doses of 5 ml/kg at 20-min intervals, or no instillation (n=6). Measurements and results: In all animals heart rate, arterial pressures, pulmonary pressures, cardiac output and blood gases were recorded at 20-min intervals. There was no deleterious effect on any hemodynamic parameter in the perflubron group, whereas systolic and mean pulmonary arterial pressure values showed a persistent decrease after the first 5 ml/kg of perflubron, from 48.7±14.1 to 40.8±11.7 mmHg and from 39.7±13.2 to 35.2±12.0 mmHg, respectively. Perflubron resulted in a significant (ANOVA P<0.01), dose-dependent increase in PaO2 values from 86.3±22.4 to a maximum of 342.4±59.4 mmHg at a dose of 25 ml/kg; the other groups showed no significant increase in PaO2. Conclusions: Tracheal instillation of perflubron in induced ALI results in a dose-dependent increase in PaO2 and has no deleterious effect on hemodynamic parameters

Partial liquid ventilation improves lung function in ventilation-induced lung injury

Disturbances in lung function and lung mechanics are present after ventilation with high peak inspiratory pressures (PIP) and low levels of positive end-expiratory pressure (PEEP). Therefore, the authors investigated whether partial liquid ventilation can re-establish lung function after ventilation-induced lung injury. Adult rats were exposed to high PIP without PEEP for 20 min. Thereafter, the animals were randomly divided into five groups. The first group was killed immediately after randomization and used as an untreated control. The second group received only sham treatment and ventilation, and three groups received treatment with perfluorocarbon (10 mL x kg(-1), 20 mL x kg(-1), and 20 ml x kg(-1) plus an additional 5 mL x kg(-1) after 1 h). The four groups were maintained on mechanical ventilation for a further 2-h observation period. Blood gases, lung mechanics, total protein concentration, minimal surface tension, and small/large surfactant aggregates ratio were determined. The results show that in ventilation-induced lung injury, partial liquid ventilation with different amounts of perflubron improves gas exchange and pulmonary function, when compared to a group of animals treated with standard respiratory care. These effects have been observed despite the presence of a high intra-alveolar protein concentration, especially in those groups treated with 10 and 20 mL of perflubron. The data suggest that replacement of perfluorocarbon, lost over time, is crucial to maintain the constant effects of partial liquid ventilation

Liquid lung ventilation as an alternative ventilatory support

The concept of liquid ventilation has evolved in recent years into the concept of partial liquid ventilation. In this technique, conventional mechanical ventilation is combined with intratracheal perfluorocarbon administration. Partial liquid ventilation is a promising technique for improving gas exchange during mechanical ventilation in neonatal and acute respiratory distress syndrome. The initial data showed no adverse effects on the cardiovascular system, and histological studies demonstrated that perfluorocarbons minimize or prevent the progress of lung injury in animals. Partial liquid ventilation is currently in use in human trials, and in this review we describe the principles of the technique and recently available data of its application

Surfactant impairment after mechanical ventilation with large alveolar surface area changes and effects of positive end-expiratory pressure

We have assessed the effects of overinflation on surfactant function and composition in rats undergoing ventilation for 20 min with 100% oxygen at a peak inspiratory pressure of 45 cm H2O, with or without PEEP 10 cm H2O (groups 45/10 and 45/0, respectively). Mean tidal volumes were 48.4 (SEM 0.3) ml kg-1 in group 45/0 and 18.3 (0.1) ml kg-1 in group 45/10. Arterial oxygenation in group 45/0 was reduced after 20 min compared with group 45/10 (305 (71) vs 564 (10) mm Hg); maximal compliance of the P-V curve was decreased (2.09 (0.13) vs 4.16 (0.35) ml cm H2O-1 kg-1); total lung volume at a transpulmonary pressure of 5 cm H2O was reduced (6.5 (1.0) vs 18.8 (1.4) ml kg-1) and the Gruenwald index was less (0.22 (0.02) vs 0.40 (0.05)). Bronchoalveolar lavage fluid from the group of animals who underwent ventilation without PEEP had a greater protein concentration (2.18 (0.11) vs 0.76 (0.22) mg ml-1) and a greater minimal surface tension (37.2 (6.3) vs 24.5 (2.8) mN m-1) than in those who underwent ventilation with PEEP. Group 45/0 had an increase in non-active to active total phosphorus compared with nonventilated controls (0.90 (0.16) vs 0.30 (0.07)). We conclude that ventilation in healthy rats with peak inspiratory pressures of 45 cm H2O without PEEP for 20 min caused severe impairment of pulmonary surfactant composition and function which can be prevented by the use of PEEP 10 cm H2O

Comparison of exogenous surfactant therapy, mechanical ventilation with high end-expiratory pressure and partial liquid ventilation in a model of acute lung injury

We have compared three treatment strategies, that aim to prevent repetitive alveolar collapse, for their effect on gas exchange, lung mechanics, lung injury, protein transfer into the alveoli and surfactant system, in a model of acute lung injury. In adult rats, the lungs were ventilated mechanically with 100% oxygen and a PEEP of 6 cm H2O, and acute lung injury was induced by repeated lung lavage to obtain a PaO2 value < 13 kPa. Animals were then allocated randomly (n = 12 in each group) to receive exogenous surfactant therapy, ventilation with high PEEP (18 cm H2O), partial liquid ventilation or ventilation with low PEEP (8 cm H2O) (ventilated controls). Blood-gas values were measured hourly. At the end of the 4-h study, in six animals per group, pressure-volume curves were constructed and bronchoalveolar lavage (BAL) was performed, whereas in the remaining animals lung injury was assessed. In the ventilated control group, arterial oxygenation did not improve and protein concentration of BAL and conversion of active to non-active surfactant components increased significantly. In the three treatment groups, PaO2 increased rapidly to > 50 kPa and remained stable over the next 4 h. The protein concentration of BAL fluid increased significantly only in the partial liquid ventilation group. Conversion of active to non-active surfactant components increased significantly in the partial liquid ventilation group and in the group venti

Results of Implementing an Enhanced Recovery After Bariatric Surgery (ERABS) Protocol

Background: With the increasing prevalence of morbid obesity and healthcare costs in general, interest is shown in safe, efficient, and cost-effective bariatric care. This study describes an Enhanced Recovery After Bariatric Surgery (ERABS) protocol and the results of implementing such protocol on procedural times, length of stay in hospital (LOS), and the number of complications, such as readmissions and reoperations. Methods: Results of implementing an ERABS protocol were analyzed by comparing a cohort treated according to the ERABS protocol (2012–2014) with a cohort treated before implementing ERABS (2010–2012). Differences between both cohorts were analyzed using independent t tests and chi-squared tests. Results: A total of 1.967 patients (mean age 43.3 years, 80 % female) underwent a primary bariatric procedure between 2010 and 2014, of which 1.313 procedures were performed after implementation of ERABS. A significant decrease of procedural times and a significantly decreased LOS, from 3.2 to 2.0 nights (p < 0.001), were seen after implementation of ERABS. Significantly more complications were seen post-ERABS (16.1 vs. 20.7 %, p = 0.013), although no significant differences were seen in the number of major complications. Conclusion: Implementation of ERABS can result in shorter procedural times and a decreased LOS, which may lead to more efficient and cost-effective bariatric care. The increase in complications was possibly due to better registration of complications. The main goal of an ERABS protocol is efficient, safe, and evidence-based bariatric care, which can be achieved by standardization of the total process