Sevoflurane, but not propofol, reduces the lung inflammatory response and improves oxygenation in an acute respiratory distress syndrome model A randomised laboratory study

CONTEXTAcute respiratory distress syndrome is characterised by activation of the inflammatory cascade. The only treatment that reduces the mortality rate associated with this syndrome is lung protective ventilation, which requires sedation of patients. Sedation in critical care units is usually induced intravenously, although there is reason to believe that inhaled anaesthetics are a suitable alternative. Sevoflurane has recently been shown to modulate the lung inflammatory response in a model of lung injury more favourably than propofol.OBJECTIVEThe goal of this study was to confirm whether or not sevoflurane is more effective than propofol in ameliorating the inflammatory response in an animal model of acute respiratory distress syndrome.DESIGNA prospective, randomised, controlled study.SETTINGResearch foundation laboratory at the Hospital Clinico Universitario, Valencia, Spain.EXPERIMENTAL ANIMALSSixteen Landrace/large white crossbred pigs weighing 30 to 45kg.INTERVENTIONSAnimals were allocated randomly to one of two groups: one sedated with intravenous propofol 5 to 7mgkg(-1)h(-1) (group P) and the other with sevoflurane, administered using an AnaConDa device to obtain an end-tidal concentration of 1.5% (group S). Monitoring, lung protective ventilation and anaesthetic management were identical in both groups.MAIN OUTCOME MEASURESThe PaO2/FiO(2) ratio and cytokine concentrations in bronchoalveolar lavage specimens were determined at 10, 150 and 240min after confirmation of acute respiratory distress syndrome (PaO2/FiO(2)<26.7kPa).RESULTSAt 240min, median and interquartile range (IQR) concentrations of cytokines in bronchial lavage specimens in group S were lower than those in group P [interleukin-1 (IL-1) 53, IQR 16-140 vs. 311, IQR 183-637pgml(-1), P=0.04; tumour necrosis factor- 347, IQR 161-433 vs. 552, IQR 475-649pgml(-1), P=0.04; and IL-6 101, IQR 76-282 vs. 580, IQR 369-701pgml(-1), P=0.03]. The polymorphonuclear neutrophil count was also lower in group S (P=0.007), which also had a higher PaO2/FiO(2) ratio.TRIAL REGISTRATIONGE-015/09.CONCLUSIONIn an animal model of acute respiratory distress syndrome, sevoflurane ameliorates the lung inflammatory response and improves oxygenation to a greater extent than propofol.