Is vecuronium a long-acting neuromuscular blocking agent in neonates and infants?

Vecuronium was used as the only neuromuscular blocking agent in 81 paediatric patients (neonates to adolescents) during fentanyl and nitrous oxide anaesthesia. The thenar electromyogram was used to monitor neuromuscular blockade. Neonates and infants had a mean requirement of vecuronium 105 micrograms kg-1 during the first 1 h of anaesthesia, to establish and maintain 90-98% neuromuscular blockade, compared with a mean requirement of 217 micrograms kg-1 for children aged 3-10 yr (P less than 0.05). Vecuronium 100 and 150 micrograms kg-1 maintained neuromuscular blockade greater than 90% for 59 and 110 min, respectively, in neonates and infants, but only for 18 and 38 min in children and for 37 and 68 min in adolescents (P less than 0.05). Vecuronium may be regarded as a long-acting neuromuscular blocking agent in patients aged less than 1 yr.