[Effect of dexmedetomidine on anesthetic requirements in cardiovascular surgery].

BACKGROUND: An anesthetic-sparing effect of dexmedetomidine has been shown in several studies. We investigated the effect of dexmedetomidine on anesthetic requirements in 24 patients undergoing cardiovascular surgery.

METHODS: Patients were randomly divided into two groups in which continuous infusion of dexmedetomidine was started before induction of anesthesia (DEX group, n = 12) or when closing the sternum (control group, n = 12). Dexmedetomidine was administered intravenously at 0.7 microg x kg(-1) x hr(-1) after a bolus infusion at 6.0 microg x kg(-1) x hr(-1) for 10 min. All patients received total intravenous anesthesia with propofol and fentanyl.

RESULTS: Mean effect-site concentration of propofol was significantly lower in the DEX group than in the control group (1.9 +/- 0.3 microg x ml(-1) vs 2.5 +/- 0.8 microg x ml(-1)). Mean effect-site concentration of fentanyl in the DEX group was significantly lower than that in the control group (1.93 +/- 0.41 ng x ml(-1) vs 2.67 +/- 0.70 ng x ml(-1).

CONCLUSIONS: The combined use of dexmedetomidine decreases anesthetic requirements in cardiovascular surgery.