An evaluation of priming with vecuronium.

Priming with vecuronium was evaluated in three groups of patients. Group 1 (n = 10) received tubocurarine 0.05 mg kg-1, group 2 (n = 19) received physiological saline and group 3 (n = 21) received vecuronium 0.012 mg kg-1. After 4 min maximum inspiratory pressure was measured. Anaesthesia was induced with thiopentone 6-8 mg kg-1 and controlled ventilation with nitrous oxide and oxygen via a face mask instituted. The ulnar nerve was stimulated at the wrist. At 5 min group 1 patients received suxamethonium 1.5 mg kg-1, group 2 received vecuronium 0.072 mg kg-1, and group 3 received vecuronium 0.060 mg kg-1. Intubation was accomplished at 6.5 min in all patients in group 1, 89% in group 2 and 90% in group 3. Patients in group 1 had no twitch response to stimulation at the time of intubation. Mean T4:T1 ratios at 6.5 min were 0.82 in group 2 and 0.61 in group 3 (P less than 0.05). Intubating conditions were excellent in all group 1 patients, and in 53% and 67% of groups 2 and 3, respectively. Two patients in group 3 did not tolerate the priming dose and many had subjective complaints. Four group 3 patients could not sustain head lift and five showed decreased inspiratory pressure. Priming did not improve intubating conditions when compared with a single bolus technique and was not well tolerated.