Effects of propofol vs methohexital on neutrophil function and immune status in critically ill patients

Patients with severe brain injury often require long-term sedation and have a high incidence of nosocomial infections, causing an increased mortality rate. However, whether anesthetic drugs might contribute to immunosuppressive effects remains unclear.

In this prospective study, we investigated the effects of propofol (4-6 mg x kg(-1) x h(-1)) and methohexital (1-3 mg x kg(-1) x h(-1)) on neutrophil leukocyte function and immune status in 21 patients with brain injury who either received propofol (n = 12; 9 male, 3 female; mean age, 51 +/- 15 years) or methohexital (n = 9; 8 male, 1 female; mean age, 48 +/- 17 years) after admission to the intensive care unit (ICU). Both sedatives were administered over 7 days and individual dosage was adapted according to clinical requirements. Neutrophil leukocyte function was assessed as phagocytosis and respiratory oxidative burst activity. Furthermore, leukocyte subpopulations, and surface markers of lymphocytes and monocytes (CD3; CD4; CD45RO; CD4/CD45RO; CD25; CD4 and CD25; CD54; CD69; CD14/HLA-DR; CD8; CD3/HLA-DR; CD4 : CD8 ratio) were assessed. Blood samples were drawn on ICU admission, and on days 3, 7, and 14. Patients' demographics were compared by Wilcoxon test and laboratory results were compared by analysis of variance (ANOVA) for repeated measurements, with an all pairwise multiple comparison procedure.

There were no significant differences in neutrophil oxidative burst and phagocytosis within or between the two groups at the different time points. With respect to cellular markers of lymphocytes and monocytes, all values throughout remained in the normal range.

Methohexital and propofol exhibited no significant effects on neutrophil function and immune status in patients with severe brain injury requiring long-term sedation.