Post-tetanic burst count: a stimulating pattern for profound neuromuscular blockade.

The purpose of this study was to compare the pattern of recovery from vecuronium 0.07 mg.kg-1 induced neuromuscular blockade using post-tetanic burst count (PTBC)-(three short tetanic bursts of 0.2 msec duration every 20 msec given every second following a tetanus), and post-tetanic count (PTC)-(0.2 msec single twitch stimuli given every second following a tetanus) using an accelerometer in 60 adult patients during nitrous oxide-oxygen-isoflurane anaesthesia. In addition, the relationship among PTBC, PTC, and T1 (the 1st response in the train-of-four (TOF) stimulation) was examined to investigate whether the PTBC had an advantage over the PTC or TOF for evaluating intense neuromuscular blockade. The PTBC was greater than PTC during the 15-35 min after the administration of vecuronium (unpaired t test with Bonferroni's correction, P < 0.05). Time to the return of PTB response was shorter than that of PTT (17.7 +/- 3.2 vs 22.7 +/- 3.7 min, unpaired t test, P = 0.0005). Time from the return of PTB to that of T1 was longer than the time from the return of PTC to that of T1 (13.3 +/- 2.6 vs 9.2 +/- 2.8 min, unpaired t test, P = 0.0003). At the return of T1, PTBC was greater than PTC (14.3 +/- 6.9 vs 9.4 +/- 2.3, unpaired t test, P = 0.0153). These results suggest that, using PTBC, a more profound level of neuromuscular blockade can be evaluated than that using PTC.