Effects of different preparations of propofol, diazepam, and etomidate on human neutrophils in vitro.

BACKGROUND

Intravenous anaesthetics and sedatives can influence polymorphonuclear cell (PMN) functions. Some of the drugs for sedation and anaesthesia have been alternatively dissolved in lipid solutions containing medium (MCT) and/or long chain (LCT) triglycerides. The in vitro effects of two different diazepam (benzyl-alcohol, LCT/MCT), etomidate (propylene-glycol, LCT/MCT), and propofol (LCT, LCT/MCT) preparations on respiratory burst (RB) and phagocytosis of human PMNs were studied.

METHODS

Diazepam (2, 20 microg ml(-1)), etomidate (0.5, 5 microg ml(-1)), and propofol (6, 60 microg ml(-1)) were investigated in clinical and 10-fold concentrations with flow cytometric assays. The RB was measured with the fluorescent dye rhodamine after induction with Escherichia coli or formyl-methionyl-leucylphenylalanine (FMLP) following priming with tumour necrosis factor alpha (TNF-alpha). Phagocytosis of PMNs was carried out in whole blood after incubation with fluorescein-labelled E. coli.

RESULTS

LCT-propofol at 60 microg ml(-1) reduced the percentage of PMNs with RB activity after induction with E. coli (52.8+/-20.4) and TNF-alpha/FMLP (10.8+/-5.1)) as well as the percentage of phagocytosing PMNs (48.9+/-19.5) in contrast to LCT/MCT-propofol, which augmented all parameters (85.4+/-10.1, 50.3+/-12.7, 66.5+/-12.5). Also the higher concentrations of LCT/MCT-diluted etomidate and diazepam increased the percentage of RB positive PMNs compared to the alternative compositions. The percentage of phagocytosing PMNs was less reduced with 20 microg ml(-1) LCT/MCT-diazepam (85.2+/-6.9) than with the same concentration of benzyl-alcohol diluted diazepam (68.8+/-12.2) compared to the control.

CONCLUSION

The in vitro effects of diazepam, etomidate, and propofol are dependent on the solvent applied. The tested LCT/MCT preparations reduce the inhibitory effects on the bacterial killing capacity of PMNs found after incubation with propyleneglycol, benzyl-alcohol, or LCT preparations, respectively.