[Clinical significance of posttetanic count (PTC) during onset and spontaneous offset of neuromuscular blockade induced by vecuronium].

To compare the clinical difference of posttetanic count (PTC) during onset and spontaneous offset, the changes of PTC during an intense neuromuscular blockade induced by vecuronium (0.08 mg.kg-1, i.v.) were measured using a neuromuscular transmission analyzer in 64 adult patients anesthetized with nitrous oxide and halothane. Furthermore, intubation score was evaluated when zero PTC was obtained. The obvious movement of diaphragm associated with endotracheal intubation was observed in 9 out of 20 patients (45%) even when it was performed after obtaining zero PTC. The difference of PTC responses between the onset and the offset was found. The difference was that, during the onset, a tetanic response was observed obviously and the height of the posttetanic single twitch was low, and during offset, even when no response was observed, the height of a posttetanic single twitch response was high with the same PTC. These facts indicate that the same PTC has different clinical significance during onset and offset.