Rocuronium versus succinylcholine for rapid-sequence induction using a variation of the timing principle

Abstract

Study objective: To determine if, using a variation of the "timing" principle, 0.6 mg/kg of rocuronium can achieve an onset time and intubating conditions similar to those achieved with succinylcholine.

Study design: Prospective, randomized, double-blind clinical comparison.

Setting: Operating room in a university medical center.

Patients: 42 ASA physical status I and II patients undergoing general anesthesia for elective surgery.

Interventions: All patients were fitted with a Grass FT-10 force transducer attached to the thumb. Supramaximal stimulation was applied to the ulnar nerve with a variable current peripheral nerve stimulator. 22 patients (succinylcholine group) received a placebo bolus injection followed 20 seconds later by thiopental 4 to 5 mg/kg and succinylcholine 1 mg/kg; 20 additional patients (rocuronium group) received a bolus dose of rocuronium 0.6 mg/kg followed 20 seconds later by thiopental 4 to 5 mg/kg and a placebo bolus injection.

Measurements and main results: We measured the onset time from administration of the muscle relaxant to 95% twitch reduction and assessed the quality of intubating conditions 60 seconds after the induction of anesthesia. There was a significant difference in the mean onset time of rocuronium (72 sec) versus succinylcholine (42 sec, p < 0.0001). However, there was no significant difference in intubating conditions 60 seconds after administration of thiopental.

Conclusion: Rocuronium given 20 seconds prior to thiopental provides intubating conditions equivalent to thiopental-succinylcholine for rapid-sequence inductions, circumventing rocuronium's longer onset time to 95% neuromuscular blockade.