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

Objective: In the present study, the authors compared continuous infusion t o bolus administration of sufentanil and midazolam in patients undergoing m itral valve surgery. The purpose of the study was to evaluate the hemodynam ic variability, total dose, effective plasma drug concentrations, and simpl icity 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 consi sted of sufentanil, up to 2 mu g/kg, and midazolam, 0.05 to 0.15 mg/kg, fol lowed by atracurium, 0.5 mg/kg. Anesthesia was maintained in the bolus grou p with predetermined boluses of sufentanil, 2 mu g/kg, and midazolam, 0.03 mg/kg, Boluses were not administered if blood pressure was within 20% of ba seline. The continuous-infusion group received sufentanil, 3.6 mu g/kg/h, a nd midazolam, 0.08 mg/kg/h, started immediately after induction. The infusi on rate was reduced to sufentanil, 1.8 mu g/kg/h, and midazolam, 0.04 mg/kg /h, after sternotomy and was discontinued at skin closure. Atracurium was i nfused at a rate of 0.5 mg/kg/h up to sternal closure in both groups. No in halation agents were used. Measurements and Main Results: Hemodynamic variability between the groups w as not significant. Total sufentanil dose was 773 +/- 186 mu g in the conti nuous-infusion group and 610 +/- 184 mu g in the bolus group (p = 0.01). To tal midazolam dose was 14.4 +/- 3 mg and 11.2 +/- 3 mg in the continuous-in fusion and bolus groups, respectively. There were 3.46 (range, 0 to 7) addi tional 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 concen trations at extubation in the bolus group (17 +/- 6.7 ng/mL) were similar t o 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. Copyright (C) 1999 by W.B. Saunders Comp any.