title: Depth of block after divided doses of mivacurium spaced 60 seconds apart.
abstract: We compared the depth of block attained after divided- and single-dose administration of mivacurium to evaluate our clinical impression that the former regimen resulted in a lesser depth of block. In 30 patients anesthetized with midazolam, fentanyl, thiopental, and nitrous oxide, adductor pollicis contraction was measured in response to train-of-four stimulation at 12-s intervals. Patients then received (by random assignment) mivacurium as a single 0.15 mg/kg bolus (Group I) or two 0.075 mg/kg (Group II) boluses separated by 60 s. All 15 Group I patients developed > or = 95% twitch (T1) depression, and 10/15 attained 100% depression; the maximum depression (mean +/- SD) was 99.1% +/- 1.4%. Only 8/15 Group II patients achieved > or = 95% T1 depression (P < 0.05 for the interregimen comparison with chi 2 analysis), and only 4/15 achieved 100% depression (P = 0.07); the maximum depression was 92.2% +/- 12.9% (P < 0.05 by unpaired t-test). Thus, administration of mivacurium in divided doses spaced 60 s apart does not provide the depth of neuromuscular block that is attained when a single bolus of the same total dose is administered.
authors.affiliation: Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06510.
authors.forename: D G
authors.initials: DG
authors.lastname: Silverman
authors.forename: S J
authors.initials: SJ
authors.lastname: Brull
mesh_terms: D004334:Drug Administration Schedule; D006801:Humans; D007546:Isoquinolines / Q000008:administration & dosage* / Q000494:pharmacology; D000077590:Mivacurium; D009407:Nerve Block; D009467:Neuromuscular Depolarizing Agents / Q000008:administration & dosage* / Q000494:pharmacology; D011446:Prospective Studies
chemical_list: D007546:Isoquinolines; D009467:Neuromuscular Depolarizing Agents; D000077590:Mivacurium