title: Dose-response and minimum time to satisfactory intubation conditions after mivacurium in children.
abstract: We assessed neuromuscular blocking effects and tracheal intubation conditions following mivacurium in 121 anaesthetised children aged 1-10 years. The study was conducted in three parts. Parts 1 and 2 were undertaken during thiopentone-alfentanil-nitrous oxide anaesthesia; neuromuscular blockade was evaluated by recording the force of contraction of the adductor pollicis in response to train-of-four stimulation at 0.1 Hz. In part 1 the potency of mivacurium was determined in 15 children using a single dose-response technique; in part 2 onset and recovery times were determined in six children following a dose of mivacurium 0.2 mg.kg-1. In part 3 of the study, clinical intubation conditions were assessed in two groups of 50 children whose tracheas were intubated 60 or 90 s after injection of mivacurium 0.2 mg.kg-1 during thiopentone-nitrous oxide anaesthesia. The ED50 and ED95 of mivacurium were 54 and 105 micrograms.kg-1 respectively. The times to 90% and 100% depression of control twitch were 1.3 (0.3) and 1.9 (0.5) min; times to 5%, 25%, 75% and 90% recovery were 6.4 (1.0), 8.4 (1.1), 12.5 (1.1) and 14.4 (1.9) min, respectively. Intubation conditions were rated satisfactory in 33/50 children (0.66, 95% confidence interval 0.51-0.79) at 60 s and in 49/50 children (0.98, 95% confidence interval 0.89-1.0) at 90 s (p = 0.0001). Intubation conditions 90 s after mivacurium 0.2 mg.kg-1 were significantly better than those obtained in 10 patients given anaesthetic drugs alone (p = 0.002).
authors.affiliation: University Department of Anaesthesia, Royal Manchester Children's Hospital, Pendlebury.
authors.forename: A
authors.initials: A
authors.lastname: McCluskey
authors.forename: G
authors.initials: G
authors.lastname: Meakin
mesh_terms: D015760:Alfentanil; D000768:Anesthesia, General; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007223:Infant; D007442:Intubation, Intratracheal; D007546:Isoquinolines / Q000008:administration & dosage / Q000494:pharmacology*; D000077590:Mivacurium; D009469:Neuromuscular Junction / Q000187:drug effects*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage / Q000494:pharmacology*; D009609:Nitrous Oxide; D013874:Thiopental; D013997:Time Factors
chemical_list: D007546:Isoquinolines; D003473:Neuromuscular Nondepolarizing Agents; D015760:Alfentanil; D000077590:Mivacurium; D013874:Thiopental; D009609:Nitrous Oxide