title: Train-of-four recovery after pharmacologic antagonism of pancuronium-, pipecuronium-, and doxacurium-induced neuromuscular block in anaesthetized humans.
abstract: Previous studies have suggested that the increased duration of action of long-acting neuromuscular relaxants may make their pharmacologic antagonism more difficult and, thus, increase the likelihood of residual block. This hypothesis was tested in healthy, adult humans who received a background of isoflurane/N2O/fentanyl anaesthesia. Study subjects were paralyzed with either pancuronium (N = 8), pipecuronium (N = 8), or the longer-acting relaxant, doxacurium (N = 8). Neuromuscular function was monitored, and, using a blinded, randomized study design, the relaxants were titrated to identify the ED95 dose in each patient. Thereafter, spontaneous recovery was observed until there was 25% of baseline response to the first supramaximal twitch (T1) in a train-of-four (TOF). At this time, the block was antagonized with neostigmine 0.07 mg/kg and glycopyrrolate 0.014 mg/kg i.v., and recovery of TOF was recorded. Spontaneous recovery to 25% of the baseline T1 response occurred at 52 +/- 14 min (mean +/- SD) following administration of either pancuronium and pipecuronium, and 85 +/- 33 min following doxacurium (P < 0.05 for doxacurium versus pancuronium and pipecuronium). In doxacurium-treated patients, reversal of block with neostigmine was less predictable and less complete than with the other two relaxants. For example, the ratio of the fourth to first twitch (T4/T1) of the TOF at 10 and 15 min after reversal was significantly less with doxacurium (59 +/- 14% and 61 +/- 16%, respectively) than with either pancuronium (75 +/- 6% and 75 +/- 10%) or pipecuronium (76 +/- 9% for both).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, Mayo Clinic, Rochester, USA.
authors.forename: L W
authors.initials: LW
authors.lastname: Stinson
authors.forename: W L
authors.initials: WL
authors.lastname: Lanier
authors.forename: R L
authors.initials: RL
authors.lastname: Lennon
mesh_terms: D000758:Anesthesia; D005260:Female; D006801:Humans; D007546:Isoquinolines / Q000037:antagonists & inhibitors*; D008297:Male; D009388:Neostigmine / Q000494:pharmacology; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D003473:Neuromuscular Nondepolarizing Agents / Q000037:antagonists & inhibitors*; D010197:Pancuronium / Q000037:antagonists & inhibitors*; D017300:Pipecuronium / Q000037:antagonists & inhibitors*
chemical_list: D007546:Isoquinolines; D003473:Neuromuscular Nondepolarizing Agents; D017300:Pipecuronium; D009388:Neostigmine; D010197:Pancuronium; C049429:doxacurium