Use of 100-Hertz tetanus as an index of recovery from pancuronium-induced non-depolarizing neuromuscular blockade.

During recovery from non-depolarizing neuromuscular blockade the evoked response to train-of-four (TOF), 100-HZ tetanus (T100) and 50-HZ tetanus (T50) was measured in 10 patients. When the TOF fade ratio exceeded 0.70, tetanic tension to T50 was well sustained. However, even at TOF ratios as high as 0.88 a 2-second tetanic response to T100 showed marked fade. T100 stimulation appears to be too sensitive a test to residual curarization for routine clinical use. Fade on T100 may be quite apparent at a time when the use of additional neuromuscular antagonists are not indicated and may be counterproductive.