title: Effects of bolus administration of ORG-9426 in children during nitrous oxide-halothane anesthesia.
abstract: ORG-9426 is a new steroidal nondepolarizing neuromuscular blocking drug. We determined the dose-response relationship of ORG-9426 in 62 children (aged 1-5 yr) during nitrous oxide-halothane anesthesia by means of log-probit transformation and least-squares linear regression of the initial dose and response. Twelve additional patients received a bolus of 600 micrograms/kg (2 X the dose estimated to produce 95% depression of neuromuscular function [ED95]) of ORG-9426. Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation of the ulnar nerve at 2 Hz for 2 s at 10-s intervals. To determine the dose-response relationship, patients randomly received initial bolus doses of 120 (n = 15), 160 (n = 16), 200 (n = 16), or 240 (n = 15) micrograms/kg ORG-9426. The resulting dose estimated to produce 50% depression of neuromuscular function (ED50) and ED95 were 179 and 303 micrograms/kg, respectively. Time from administration of 600 micrograms/kg to onset of 90% and 100% neuromuscular block was 0.8 +/- 0.1 (0.5-1.3) and 1.3 +/- 0.2 (0.7-2.8) min. The time to recovery of neuromuscular transmission to 25% (T25) was 26.7 +/- 1.9 (17.2-39.0) min. The recovery index (T25-75) was 11.0 +/- 1.6 (6.0-22.8) min, and the time to complete recovery of the magnitude of the fourth response to a train-of-four stimuli divided by the magnitude of the first response (T4/T1) greater than or equal to 0.75 was 41.9 +/- 3.2 (26.5-57.7) min.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pennsylvania 15213-2583.
authors.forename: S K
authors.initials: SK
authors.lastname: Woelfel
authors.forename: B W
authors.initials: BW
authors.lastname: Brandom
authors.forename: D R
authors.initials: DR
authors.lastname: Cook
authors.forename: J B
authors.initials: JB
authors.lastname: Sarner
mesh_terms: D000732:Androstanols / Q000008:administration & dosage*; D000769:Anesthesia, Inhalation; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D006221:Halothane; D006801:Humans; D007223:Infant; D007262:Infusions, Intravenous; D009466:Neuromuscular Blocking Agents / Q000008:administration & dosage*; D009609:Nitrous Oxide; D000077123:Rocuronium; D013514:Surgical Procedures, Operative
chemical_list: D000732:Androstanols; D009466:Neuromuscular Blocking Agents; D009609:Nitrous Oxide; D006221:Halothane; D000077123:Rocuronium