Department of Anesthesiology

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Twitch, tetanus and train-of-four as indices of recovery from nondepolarizing neuromuscular blockade.

TitleTwitch, tetanus and train-of-four as indices of recovery from nondepolarizing neuromuscular blockade.
Publication TypeJournal Article
Year of Publication1981
AuthorsAli HH, Savarese JJ, Lebowitz PW, Ramsey FM
JournalAnesthesiology
Volume54
Issue4
Pagination294-7
Date Published1981 Apr
ISSN0003-3022
KeywordsElectric Stimulation, Humans, Muscle Contraction, Neuromuscular Junction, Neuromuscular Nondepolarizing Agents
Abstract

This study was undertaken to compare the sensitivities of the train-of-four response (2 Hz for 2 s), the single twitch (0.15 Hz), and the tetanic response (50 Hz for 5 s) as indices of residual nondepolarizing block. Spontaneous or induced recovery of evoked thumb adduction in response to ulnar nerve stimulation was studied. One hundred and seven adult surgical patients were divided according to the relaxant used, into six groups. We found that when the single twitch recovered to control height, the train-of-four ratio was well below 1.0. This ratio was significantly lower during spontaneous recovery than following neostigmine antagonism of the block (P less than 0.01). The tetanic response was fully sustained when the train-of-four ratio was above 0.7. When the ratio was less than 0.7, variable degrees of fade of tetanus were evident. Analysis of variance indicated similar train-of-four ratios among the six groups at complete recovery of the single twitch irrespective of the relaxant technique used (P less than 0.1). It is concluded that a train-of-four ratio of 0.7 or higher reliably indicates the recovery of the single twitch to control height and a sustained response to tetanic stimulation at 50 Hz for 5 s. The clinical significance of this study is as follows: the train-of-four response provides the same indication of clinical recovery from nondepolarizing block as obtained from tetanic stimulation at a physiological frequency; and reliance on the recovery of the single twitch to control height as a criterion of spontaneous return to normal clinical neuromuscular function may be misleading.

Alternate JournalAnesthesiology
PubMed ID6452074
Grant ListGM-15904-04 / GM / NIGMS NIH HHS / United States