Pulmonary antibacterial defense mechanisms are depressed by halothane.

Pulmonary antibacterial activity was determined by challenging halothane-exposed and control mice to radiolabeled (32P) Staphylococcus aureus produced by an aerosol generator and by determining the relative changes in viable bacterial and radioisotope counts in ground lung immediately after exposure and 4 hours later. Mice that were anesthetized for 4 hours with 1 or 2 MAC halothane and allowed to recover for 1 hour showed higher 4-hour bacterial counts when compared to controls, while radioisotope counts were the same in both groups. These data indicate that 1 and 2 MAC halothane anesthesia is associated with depressed lung bactericidal activity but that physical clearance mechanisms are not depressed.