The effects of intravenous anaesthetic agents on human neutrophil chemiluminescence.

Intact neutrophil function is essential for the defence against infection. Any alteration in neutrophil function, which decreases their ability to phagocytose and kill bacteria, might contribute to mortality and morbidity. We investigated the effects of clinical concentrations of thiopentone, Alfathesin, methohexitone, morphine, lidocaine and diazepam on the microbicidal oxidative function of human neutrophils. The oxidative activity was assessed utilizing the technique of chemiluminescence, which is a measure of free radical generation. Thiopentone and Alfathesin produced a significant dose dependent depression in chemiluminescence. There was a 27 per cent reduction in activity with thiopentone 5 micrograms X ml-1, a concentration equivalent to the free plasma concentration achieved following an anaesthetizing dose of thiopentone. There was a 55 per cent reduction in chemiluminescence at an alphaxolone concentration of 1.25 micrograms X ml-1, a concentration equivalent to the free plasma level obtained after induction of Alfathesin anaesthesia. The effect of thiopentone and Alfathesin was reversed by cell washing. Methohexitone, morphine, diazepam, and lidocaine caused no significant reduction in chemiluminescence over the dose ranges studied. These observations indicate that thiopentone and Alfathesin can adversely affect leucocyte function in vitro and, therefore, may contribute to impaired host resistance in the perioperative period and in the intensive care unit.