Facilitation of rapid-sequence intubation with large-dose vecuronium with or without priming

To determine the effect of priming on the intubation and onset times of vecuronium 0.3 mg/kg.

Randomized, unblinded study.

Operating rooms and postanesthetic recovery unit of a university-affiliated general hospital.

Thirty female ASA physical status I and II patients scheduled for intraperitoneal surgery divided into two groups of 15 each.

Anesthesia was induced and maintained with sufentanil, droperidol, thiopental sodium, and nitrous oxide in oxygen. Patients in Group 1 were given vecuronium 0.015 mg/kg 4 minutes before induction and vecuronium 0.285 mg/kg 1 minute after induction. Patients in Group 2 received a single 0.3 mg/kg dose of vecuronium 1 minute after thiopental sodium. The ulnar nerve was stimulated every 10 seconds with train-of-four supramaximal impulses of 0.2 millisecond duration at 2 Hz. The compound electromyogram (EMG) of the adductor pollicis was continuously recorded. The trachea was intubated when the amplitude of the EMG decreased to 15% to 25% of control. At the end of surgery, residual neuromuscular block was reversed with edrophonium 0.75 mg/kg.

All patients in Group 1 could be intubated in 80 seconds or less, and the longest onset time was 120 seconds. In Group 2, the longest intubation time was 140 seconds, and the longest onset time was 200 seconds. Clinical durations in both groups were unpredictable, ranging from 47 to 185 minutes in Group 1 and from 63 to 160 minutes in Group 2. Ten of the 30 patients required an additional 0.5 mg/kg of edrophonium for antagonism of the residual neuromuscular block. There were no significant changes in heart rate or blood pressure attributable to vecuronium.

Seventy-five percent to 85% neuromuscular block of the adductor pollicis, required for atraumatic tracheal intubation, developed in 80 seconds or less when vecuronium 0.3 mg/kg was administered in divided doses and in 140 seconds or less when it was injected as a single bolus dose. Clinical duration of vecuronium 0.3 mg/kg is long and unpredictable, and reversal of residual neuromuscular block may require larger doses of anticholinesterases. It is recommended that an intubating dose of vecuronium 0.3 mg/kg be used only in patients undergoing long surgical procedures that require prolonged postanesthetic mechanical ventilation.