Complement activation by propofol and its effect during propofol anaesthesia

We have examined whether propofol activates complement. In the first study, blood was mix-ed with saline, propofol or the lipid solvent for propofol, and the activated complement 3 (C3a) and 4 (C4a) concentrations in the supe rnatant were assayed. In the second study, blood and propofol were mixed wi th various levels of nafamostat mesilate (anti-complement agent) up to 0.3 mmol/l and the C3a was assayed. In the third study, the time course of plas ma C3a concentration in patients during propofol anaesthesia was examined T he results showed that the lipid solvent activated complement and produced similar levels of C3a to propofol, probably via both the classical and alte r-native pathways. This activation was not inhibited by ally of the nafamos tat concentrations used. There was no significant change in plasma C3a conc entration during propofol anaesthesia. These results suggest that C3a is ge nerated by the lipid solvent, but its accumulation during propofol anaesthe sia is minimal.