Effects of bolus administration of ORG-9426 in children during nitrous Oxide-Halothane anesthesia

• Published in: Anesthesiology (Philadelphia) Vol. 76; no. 6; pp. 939 - 942
• Main Authors: WOELFEL, S. K, BRANDOM, B. W, COOK, D. R, SARNER, J. B
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott 01-06-1992
• Subjects: Androstanols - administration & dosage; Anesthesia, Inhalation; Anesthetics. Neuromuscular blocking agents; Biological and medical sciences; Child, Preschool; Dose-Response Relationship, Drug; Halothane; Humans; Infant; Infusions, Intravenous; Medical sciences; Neuromuscular Blocking Agents - administration & dosage; Neuropharmacology; Nitrous Oxide; Pharmacology. Drug treatments; Rocuronium; Surgical Procedures, Operative; Human; Volatile compound; Gases; Non depolarisant myorelaxant; General anesthetic; General anesthesia; Nitrogen protoxide; Child; Neuromuscular blocking; Dose activity relation
• ISSN: 0003-3022; 1528-1175
• DOI: 10.1097/00000542-199206000-00011

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.