Propofol and methohexital comparably affect polymorphonuclear leukocyte function in patients after cardiac surgery

Background

Experimental and clinical studies suggest that anesthetics have a variety of negative side effects on polymorphonuclear (PMN) leukocytes, which play a vital role in the defense against invading bacteria. In this study, we analyzed the effects of propofol and methohexital on PMN leukocyte function in patients after cardiac surgery.

Patients and methods

In this observational clinical study, we studied 46 patients undergoing elective cardiac surgery who postoperatively either received propofol (n = 29) or methohexital (n = 17). Patients in the propofol group (P) (19 males, 10 females) had a mean age of 65 ± 11 (range 36–80) years. In the methohexital group (M) (12 males, five females) the mean age was 65 ± 8 (range 43–77) years. Both sedatives were administered according to clinical requirements. PMN leukocyte function was assessed as respiratory oxidative burst and expressed as the percent of oxidating cells (normal 70–100%). Furthermore, the mean fluorescence intensity (MFI) was determined as a measure of intracellular uptake of bacteria. Both variables were assessed before induction of anesthesia (MP1), on ICU admission after cardiac surgery (beginning of sedative administration) (MP2), 6 hours after ICU admission (MP3) and 24 hours after beginning of anesthesia (MP4). Patients' demographics and measurement results were compared by t test and analysis of variance for repeated measures.

Results

Both groups were well matched in terms of patient demographics, age, body weight and duration of sedative administration (P: 9.4 ± 5.4 hours vs M: 8.4 ± 5.6 hours). Within both groups, respiratory oxidative burst significantly decreased over time (MP1 and MP2 vs MP3 and MP4, respectively). For comparison, respiratory oxidative burst at MP4 was significantly higher for methohexital (82%) than propofol (72%). While oxidation decreased between MP3 and MP4 for propofol, no significant change was observed between these two time points for methohexital. For MFI, a time-dependent decrease was found for both drugs, without any difference between both groups.

Conclusions

PMN leukocyte function is comparably depressed by propofol rather than methohexital in patients after cardiac surgery.