Comparative effects of desflurane and isoflurane on vecuronium-induced neuromuscular blockade.

STUDY OBJECTIVE: To evaluate the neuromuscular effects of a nondepolarizing muscle relaxant (vecuronium) during anesthesia with equipotent concentrations of either desflurane or isoflurane. DESIGN: Randomized open study comparing effects of desflurane and isoflurane on vecuronium-induced neuromuscular blockade. SETTING: University-affiliated medical center. PATIENTS: Forty-five healthy adults undergoing elective surgical procedures randomly assigned to receive either desflurane, nitrous oxide (N2O), and vecuronium or isoflurane, N2O, and vecuronium for maintenance of general anesthesia. INTERVENTIONS: Following a standardized induction sequence, patients receiving either desflurane and N2O or isoflurane and N2O were administered bolus doses of vecuronium equal to 0.01, 0.02, or 0.03 mg/kg intravenously (IV) during the maintenance period. Neuromuscular transmission was measured using a Relaxograph monitor. MEASUREMENTS AND MAIN RESULTS: Vecuronium produced similar depression of neuromuscular function at equipotent (50% of the minimum alveolar concentration) end-tidal concentrations of isoflurane 0.6% and desflurane 3.0%. Following administration of vecuronium 0.01 to 0.03 mg/kg IV, onset times (3.4 +/- 0.4 minutes to 3.2 +/- 0.4 minutes and 3.2 +/- 0.5 minutes to 3.0 +/- 0.6 minutes), maximum T1 twitch depression (80% +/- 10% to 95% +/- 9% and 81% +/- 9% to 97% +/- 10%), clinical duration of blockade (12 +/- 5 minutes to 20 +/- 8 minutes and 10 +/- 5 minutes to 19 +/- 17 minutes), and T1 recovery times (10 +/- 3 minutes to 12 +/- 6 minutes and 10 +/- 3 minutes to 12 +/- 4 minutes) were similar in the isoflurane and desflurane treatment groups, respectively (means +/- SD). CONCLUSION: Vecuronium has similar neuromuscular effects when administered in the presence of desflurane 3% and isoflurane 0.6%.