Mivacurium chloride (BW B1090U)-induced neuromuscular blockade during nitrous oxide-isoflurane and nitrous oxide-narcotic anesthesia in adult surgical patients

• Published in: Anesthesia and analgesia Vol. 67; no. 6; pp. 495 - 499
• Main Authors: WEBER, S, BRANDOM, B. W, POWERS, D. M, SARNER, J. B, WOELFEL, S. K, COOK, D. R, FOSTER, V. J, MCNULTY, B. F, WEAKLY, J. N
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott 01-06-1988
• Subjects: Adult; Aged; Anesthesia Recovery Period; Anesthesia, General; Anesthetics. Neuromuscular blocking agents; Biological and medical sciences; Blood Pressure - drug effects; Dose-Response Relationship, Drug; Female; Fentanyl; Heart Rate - drug effects; Humans; Isoflurane; Isoquinolines; Male; Medical sciences; Middle Aged; Neuromuscular Blocking Agents - pharmacology; Neuromuscular Junction - drug effects; Neuromuscular Nondepolarizing Agents - pharmacology; Neuropharmacology; Nitrous Oxide; Pharmacology. Drug treatments; Thiopental; Human; General anesthesia; Non depolarisant myorelaxant; Nitrogen protoxide; Neuromuscular blocking; Comparative study
• ISSN: 0003-2999; 1526-7598
• DOI: 10.1213/00000539-198806000-00001

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.