Alterations of bacterial clearance induced by propofol

Background: The purpose of the study was to investigate the potential influence of the anaesthetic agent propofol on immune function in terms of systemic clearance and organ distribution of injected Escherichia coli in a rabbit model. Methods: Defined numbers of E. coli (1.3X10(8) colony-forming units, CFU) were injected intravenously 1 h after starting a 4-h infusion of the anaesthetic propofol (2 mi kg-l h-l, Disoprivan(R) 1%; n=6) or after saline application (n=6). As propofol is formulated in a 10% lipid emulsion, the lipid vehicle Intralipid(R) (2 ml kg(-1) h(-1); n=6) alone was investigated in a separate group. Parameters monitored were arterial pressure and rates of bacterial elimination from the blood. Three hours after bacterial injection, the animals were killed, and tissue samples of liver, spleen, lung, and kidney were collected for microbiological examinations. Results: Compared to saline-treated animals, infusion of propofol induced increased accumulation of E. coli in lung and spleen, thus reflecting reticuloendothelial system dysfunction. Conclusion: As the lipid emulsion by itself induced the same effects, the impaired immune function due to propofol is thought to be attributed to its solvent Intralipid(R).