title: Mivacurium infusion requirements in pediatric surgical patients during nitrous oxide-halothane and during nitrous oxide-narcotic anesthesia.
abstract: We were interested in determining the infusion rate of mivacurium required to maintain approximately 95% neuromuscular blockade during nitrous oxide-halothane (0.8% end-tidal) or nitrous oxide-narcotic anesthesia. Neuromuscular blockade was monitored by recording the electromyographic activity (Datex NMT) of the adductor pollicis muscle resulting from supramaximal stimulation of the ulnar nerve at 2 Hz for 2 s at 10-s intervals. Mivacurium steady-state infusion requirements averaged 315 +/- 26 micrograms.m-2.min-1 during nitrous oxide-halothane anesthesia and 375 +/- 19 micrograms.m-2.min-1 (mean +/- SEM) during nitrous oxide-narcotic anesthesia. Higher levels of pseudocholinesterase activity were generally associated with a higher mivacurium infusion requirement. During both anesthetics, younger age was associated with a higher infusion requirement when the infusion requirement was calculated in terms of micrograms.kg-1.min-1. This difference was not present when the infusion rate was calculated in terms of micrograms.m-2.m-1. There was no evidence of cumulation during prolonged mivacurium infusion. There was no difference in the rates of spontaneous or reversal-mediated recovery between anesthetic groups. After the termination of the infusion, spontaneous recovery to T4/T1 greater than or equal to 0.75 occurred in 9.8 +/- 0.4 min, with a recovery index, T25-75, of 4.0 +/- 0.2 min (mean +/- SEM). In summary, pseudocholinesterase activity is the major factor influencing mivacurium infusion rate in children during nitrous oxide-narcotic or nitrous oxide-halothane (0.8% end-tidal) anesthesia.
authors: Department of Anesthesiology, Children's Hospital of Pittsburgh, PA 15213-2583.
authors: B W
authors: BW
authors: Brandom
authors: J B
authors: JB
authors: Sarner
authors: S K
authors: SK
authors: Woelfel
authors: M L
authors: ML
authors: Dong
authors: M C
authors: MC
authors: Horn
authors: L M
authors: LM
authors: Borland
authors: D R
authors: DR
authors: Cook
authors: V J
authors: VJ
authors: Foster
authors: B F
authors: BF
authors: McNulty
authors: J N
authors: JN
authors: Weakly
mesh_terms: D000769:Anesthesia, Inhalation; D002091:Butyrylcholinesterase / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003975:Diazepam; D006221:Halothane; D006801:Humans; D007262:Infusions, Intravenous; D007546:Isoquinolines; D008723:Methohexital; D000077590:Mivacurium; D009020:Morphine; D009469:Neuromuscular Junction / Q000187:drug effects*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D009609:Nitrous Oxide; D010372:Pediatrics; D012601:Scopolamine
chemical_list: D007546:Isoquinolines; D003473:Neuromuscular Nondepolarizing Agents; D009020:Morphine; D000077590:Mivacurium; D012601:Scopolamine; D008723:Methohexital; D002091:Butyrylcholinesterase; D009609:Nitrous Oxide; D003975:Diazepam; D006221:Halothane