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Train‐of‐Four recovery after pharmacologic antagonism of pancuronium‐, pipecuronium‐, and doxacurium‐induced neuromuscular block in anaesthetized humans
Author(s) -
Stinson L. W.,
Lanier W. L.,
Len R. L.
Publication year - 1995
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1995.tb04086.x
Subject(s) - medicine , neostigmine , anesthesia , glycopyrrolate , fentanyl , isoflurane , atropine
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/N 2 O/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 ED 95 dose in each patient. Thereafter, spontaneous recovery was observed until there was 25% ofbaseline response to the first supramaximal twitch (Tl) 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 Tl 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‐rreated 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). At 30 min post‐neostigmine, the incidence of residual block (i.e. T4/T1 <0.70) was: pancuronium 2 patients, pipecuronium 1 patient, and doxacurium 5 patients. These studies support the hypothesis that incomplete reversal of neuromuscular block is more likely with longer‐acting neuromuscular relaxants.