ABSTRACT
Anaesthetics may compromise host defence mechanisms by adversely affecting the specific or non specific components of the normal immune response. Adverse effects of general anaesthetic agents on neutrophil functions in vitro are important as theoretically they could imply compromised function in vivo. The inhibitory effects of some anaesthetic, including intravenous [I.V.] anaesthetics, on neutrophil functions have been well documented, the use of these anaesthetics may result not only in peri -operative immunosuppression, but if used to sedate critically ill patients in the intensive care unit [ICU], may potentially further compromise an already depressed host defense mechanism. We study the effects of the most commonly used intravenous anaesthetic agents [thiopentone, ketamine, propofol and midazolam] on some functions of human neutrophils [PMNLS] [Phagocytosis, phagocytic index [P.I.], phagocytic percentage P% and respiratory burst activity] in vitro at clinical plasma concentration and 100 times. Sample of 3mL peripheral venous blood was drawn from forty healthy volunteers free from diseases not taking medication, incubated with the corresponding I.V. anaesthetic agents, using different concentrations of I.V. anaesthetic agents. The results showed that at 100 times the clinical plasma concentration, thiopentone, ketamine produced highly significant depression of neutrophil phagocytosis and non significant depression of neutrophil phagocytosis was seen with propofol and midazolam. At clinical concentration thiopentone ketamine propofol and midazolam had minimal effects on neutrophil phagocytosis. As regard to respiratory burst activity of neutrophil, there were no significant depression at both concentrations for all durgs used