title: Neuromuscular blocking effect and placental gradient of pipecuronium bromide in elective caesarean section.
abstract: We studied the suitability of pipecuronium for maintenance of neuromuscular block during 20 elective Caesarean sections under light general anaesthesia with a rapid-sequence technique facilitated by i.v. suxamethonium 0.6-0.8 mg kg-1. An initial dose of 0.035 mg kg-1 or 0.05 mg kg-1 of pipecuronium provided satisfactory relaxation of similar speed of onset (3.1 +/- 0.3 vs 3.8 +/- 0.6 min, p = 0.25); however the higher dose had a significantly longer duration of action than the lower dose (from injection to recovery to 20% of baseline 13.1 +/- 1.8 vs 39.3 +/- 6.9 min, p < 0.05). A spontaneous recovery of the T1 twitch of the train-of-four to 25% of baseline (residual block 75%) assured rapid antagonism of the residual block with either edrophonium 0.5 mg kg-1 or neostigmine 0.04 mg kg-1. A residual block greater than 80% depression of T1 markedly prolonged the time taken to achieve a satisfactory reversal. Pipecuronium had negligible cardiovascular effects and placental transfer. It had no observable effect on the newborn. In spite of some advantages, we conclude that pipecuronium is a suitable alternative during Caesarean section only when used judiciously in small doses for maintenance of neuromuscular block and recommend that the initial dose be no greater than 0.035 mg kg-1.
authors.affiliation: Department of Anesthesiology, Harbor-UCLA Medical Center, Torrance 90509.
authors.forename: C
authors.initials: C
authors.lastname: Lee
authors.forename: W F
authors.initials: WF
authors.lastname: Kwan
authors.forename: B J
authors.initials: BJ
authors.lastname: Chen
authors.forename: S K
authors.initials: SK
authors.lastname: Tsai
mesh_terms: D000293:Adolescent; D000328:Adult; D001034:Apgar Score; D002585:Cesarean Section; D004576:Electromyography; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D009466:Neuromuscular Blocking Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D017300:Pipecuronium / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy
chemical_list: D009466:Neuromuscular Blocking Agents; D017300:Pipecuronium