Effects of intravenous anesthetics on bacterial elimination in human blood in vitro

Backround: Since anesthetics are widely used in critically ill patients, this study investigates anesthetic effects on neutrophil and monocyte function concerning bacterial elimination in human whole blood. Methods: The effects of thiopental (20 and 200 μg/ml), propofol (5 and 50 μg/ml), midazolam (0.15 and 1.5 μg/ml) and ketamine (3 and 30 μg/ml) on elimination of Escherichia (E.) coli from whole blood were investigated in vitro after incubation for 1 h in both clinical (1) (n=10) and 10‐fold higher (h) (n=11) concentrations. These data were compared to neutrophil and monocyte phagocytosis (1; n=6) and burst activity (1; n=10, h; n=11), measured by flow cytometry. To enable quantification of the clearance process, a defined number of 105 colony forming units of E. coli were added to the blood assays and bacterial growth was determined. Results: All anesthetics delayed bacterial clearance from the blood in the 10‐fold concentration (P