Accelerated onset and delayed recovery of d-tubocurarine blockade with pancuronium in infants and children

Abstract

The effect of age on the onset and duration of action of a d-tubocurarine (DTC) neuromuscular blockade with and without pancuronium priming in children was examined. Sixty ASA physical status I or II patients in three age ranges (0-1 yr, 1 -3 yr and 3-10yr) were anaesthetized with thiopentone, halothane and nitrous oxide. Each patient received either a single paralyzing dose of DTC 0.4 mg·kg-1, or DTC 0.36 mg·kg-1 preceded three minutes earlier by pancuronium 0.007 mg·kg-1. Evoked force of contraction of the adductor pollicis was measured using train-of-four stimulation applied every 12 sec. Time to 90 per cent first twitch depression after a single dose of DTC increased with increasing age (r = 0.65, p < 0.01), and was 1.6 min (SEM ± 0.3) in the 0-1 yr group, 1.9 ± 0.3 min (1-3 yr), and 5.2 ±1.2 min (3-10 yr). Time to ten per cent spontaneous recovery after single dose DTC was shorter in older individuals (r = 0.40, p < 0.05), being 36.4 ±5.1 min in infants 0-1 yr, 30.6 ±4.6 min (1-3 yr), and 24.0 ± 2.7 min (3-10 yr). Priming with pancuronium accelerated the onset significantly in all age groups with 90 per cent T1 depression occurring at 0.7 ± 0.1 min (0-1 yr), 0.9 ± 0.1 min (1-3 yr), and 2.1 ± 0.6 min (3-10 yr). However, priming delayed recovery, especially in infants. Times to ten per cent spontaneous recovery following DTC with pancuronium priming were 71.0 ± 8.1 (0-1 yr), 42.7 ±3.8 (1-3yr), and29.3 ±3.9 min (3-10 yr). It is concluded that onset and recovery from a DTC blockade are markedly age-related, and this relationship may be accentuated by pretreatment with pancuronium. © 1987 Canadian Anesthesiologists.