Continuous infusion versus bolus administration of sufentanil and midazolam for mitral valve surgery

OBJECTIVE: In the present study, the authors compared continuous infusion to bolus administration of sufentanil and midazolam in patients undergoing mitral valve surgery. The purpose of the study was to evaluate the hemodynamic variability, total dose, effective plasma drug concentrations, and simplicity of the two anesthetic techniques. DESIGN: Prospective, randomized study. SETTING: University hospital. PARTICIPANTS: Thirty patients scheduled for elective mitral valve surgery. INTERVENTIONS: Induction of anesthesia was similar in both groups and consisted of sufentanil, up to 2 microg/kg, and midazolam, 0.05 to 0.15 mg/kg, followed by atracurium, 0.5 mg/kg. Anesthesia was maintained in the bolus group with predetermined boluses of sufentanil, 2 microg/kg, and midazolam, 0.03 mg/kg. Boluses were not administered if blood pressure was within 20% of baseline. The continuous-infusion group received sufentanil, 3.6 microg/kg/h, and midazolam, 0.08 mg/kg/h, started immediately after induction. The infusion rate was reduced to sufentanil, 1.8 microg/kg/h, and midazolam, 0.04 mg/kg/h, after sternotomy and was discontinued at skin closure. Atracurium was infused at a rate of 0.5 mg/kg/h up to sternal closure in both groups. No inhalation agents were used. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variability between the groups was not significant. Total sufentanil dose was 773 +/- 186 microg in the continuous-infusion group and 610 +/- 184 microg in the bolus group (p = 0.01). Total midazolam dose was 14.4 +/- 3 mg and 11.2 +/- 3 mg in the continuous-infusion and bolus groups, respectively. There were 3.46 (range, 0 to 7) additional bolus injections in the bolus group and 0.31 (range, 0 to 1) in the continuous-infusion group (p < 0.001). Plasma sufentanil concentrations at extubation were similar in both groups (0.5 ng/mL). Plasma midazolam concentrations at extubation in the bolus group (17 +/- 6.7 ng/mL) were similar to those in the continuous-infusion group (23 +/- 5 ng/mL). CONCLUSION: The simplicity of the continuous infusion is a major advantage. This technique provides hemodynamically safe and stable conditions similar to those of bolus administration.