title: Mivacurium chloride (BW B1090U)-induced neuromuscular blockade during nitrous oxide-isoflurane and nitrous oxide-narcotic anesthesia in adult surgical patients.
abstract: The neuromuscular and cardiovascular effects of mivacurium were studied in 90 adult patients during nitrous oxide-oxygen-isoflurane (n = 45, ISO group) and nitrous oxide-oxygen-narcotic (n = 45, BAL group) anesthesia. Neuromuscular blockade was measured using electromyographic activity of the adductor pollicis muscle after supramaximal stimulation of the ulnar nerve at 2 Hz for 2 seconds at 10-second intervals. To estimate dose-response relations, three subgroups of nine patients in the ISO group received mivacurium doses of 0.025, 0.03, and 0.04 mg/kg, respectively. Similarly, three subgroups of nine patients in the BAL group received mivacurium doses of 0.03, 0.04, and 0.05 mg/kg, respectively. The ED50 and ED95 of mivacurium in each group were estimated from linear regression plots of log dose vs probit of maximum percentage depression of neuromuscular function. The estimated ED50 values for the ISO and BAL groups were 0.029 and 0.041 mg/kg, respectively. The estimated ED95 values for the ISO and BAL groups were 0.045 and 0.058 mg/kg, respectively. Recovery indexes were measured in 26 patients who received ED95 or greater doses of mivacurium in either the ISO or BAL groups. The recovery index was shorter in the BAL group (5.5 +/- 1.6 minutes [n = 10]), than in the ISO group (7.4 +/- 3.0 minutes [n = 16]). The addition of isoflurane (0.5-0.75% end-tidal concentration) to nitrous oxide-narcotic anesthesia augments the degree of neuromuscular blockade from a given dose of mivacurium and also prolongs the recovery index.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, University of Pittsburgh School of Medicine, PA.
authors.forename: S
authors.initials: S
authors.lastname: Weber
authors.forename: B W
authors.initials: BW
authors.lastname: Brandom
authors.forename: D M
authors.initials: DM
authors.lastname: Powers
authors.forename: J B
authors.initials: JB
authors.lastname: Sarner
authors.forename: S K
authors.initials: SK
authors.lastname: Woelfel
authors.forename: D R
authors.initials: DR
authors.lastname: Cook
authors.forename: V J
authors.initials: VJ
authors.lastname: Foster
authors.forename: B F
authors.initials: BF
authors.lastname: McNulty
authors.forename: J N
authors.initials: JN
authors.lastname: Weakly
mesh_terms: D000328:Adult; D000368:Aged; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005283:Fentanyl; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007530:Isoflurane; D007546:Isoquinolines; D008297:Male; D008875:Middle Aged; D000077590:Mivacurium; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000187:drug effects*; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D009609:Nitrous Oxide; D013874:Thiopental
chemical_list: D007546:Isoquinolines; D009466:Neuromuscular Blocking Agents; D003473:Neuromuscular Nondepolarizing Agents; D000077590:Mivacurium; D007530:Isoflurane; D013874:Thiopental; D009609:Nitrous Oxide; D005283:Fentanyl