ABSTRACT
Cumulative dose-response curves were constructed for pancuronium, metocurine, d-tubocurarine and gallamine in 56 children anaesthetized with thiopentone, N2O/O2 and narcotic. The dose response curves of the four relaxants did not deviate significantly from parallelism. The effective dose causing 95 per cent depression of the twitch at 0.1 Hz was: pancuronium 0.08 mg X kg-1, metocurine 0.34 mg X kg-1, d-tubocurarine 0.6 mg X kg-1, and gallamine 3.4 mg X kg-1. Thus, pancuronium is 40 times more potent than gallamine, while metocurine and d-tubocurarine are seven and four times more potent than gallamine. The recovery of twitch height from 5-25 per cent of control for pancuronium (15.6 +/- 1.7 min) was significantly faster (p less than 0.01) than metocurine (27.3 +/- 1.9 min), d-tubocurarine (32.2 +/- 4.8 min), or gallamine (30 +/- 3.3 min). Compared to studies in adults, the present data indicate that children have a tendency (statistically not significant) to require more relaxant and recover more quickly than adults.
Subject(s)
Muscle Contraction/drug effects , Neuromuscular Blocking Agents/pharmacology , Adult , Age Factors , Child , Child, Preschool , Dose-Response Relationship, Drug , Gallamine Triethiodide/pharmacology , Humans , Pancuronium/pharmacology , Tubocurarine/analogs & derivatives , Tubocurarine/pharmacologyABSTRACT
The neuromuscular and cardiovascular effects of vecuronium (Norcuron, ORG NC45) were studied in 40 adolescents (10-17 yr) and children (2-9 yr) anesthetized with 1.5% inspired halothane. Ten adolescents and ten children were given 20 micrograms/kg incremental doses of vecuronium to establish a cumulative dose-response curve during train-of-four stimulation. The ED95 dose was 56 micrograms/kg in children and 40 micrograms/kg in adolescents, children being significantly (P less than 0.01) more resistant to the neuromuscular effects of vecuronium than adolescents. Another group of 10 children and 10 adolescents received a bolus dose of 80 micrograms/kg. This dose provided satisfactory conditions for endotracheal intubation with complete suppression of train-of-four response in all adolescents and children within 2 min. Thereafter, the twitch tension recovered to 5% of control twitch height in 18.5 +/- 1.5 min, to 25% in 24.4 +/- 1.6 min, and to 95% in 43.3 +/- 2.1 min. Vecuronium (20-80 micrograms/kg) did not significantly alter the heart rate or blood pressure nor did it affect kidney or liver function as assessed by routine clinical laboratory tests. Vecuronium is a useful nondepolarizing neuromuscular blocking agent with a short to intermediate duration of action, which can be used safely in children and adolescents.
