THE INFLUENCE OF INTRAVENOUS ANESTHETICS ON POLYMORPHONUCLEAR LEUKOCYTE FUNCTION

Polymorphonuclear leukocytes (PMNL) play a vital role in the defence a gainst invading bacteria. It is known that some anaesthetics inhibit P MNL function and, thus, possibly enhance perioperative infection. We i nvestigated the effect of methohexitone, flunitrazepam, and droperidol on three bactericidal PMNL functions, i. e., superoxide anion product ion, hydrogen peroxide generation, and activity of released myeloperox idase, in vitro Approved photometrical assays were used Superoxide ani on was measured by the reduction of cytochrome C, hydrogen peroxide by the horse radish peroxidase catalysed oxidation of phenol red and mye loperoxidase by the turnover of 2,2'-azino-di(3-ethylbenzthiazoline) s ulfonic acid. Methohexitone (P less-than-or-equal-to 0.001) and flunit razepam (P less-than-or-equal-to 0.01) inhibited superoxide anion prod uction, and methohexitone (P less-than-or-equal-to 0.01) reduced hydro gen Peroxide generation but only at concentrations beyond clinical rel evance. Droperidol did not cause any alteration of the PMNL functions tested Consequently, it seems unlikely that the usual doses of methohe xitone, flunitrazepam, or droperidol promote bacterial infections in v ivo by impairing the activity of myeloperoxidase or by inhibiting the generation of superoxide anion or hydrogen peroxide.