Post-tetanic burst: a new monitoring method for intense neuromuscular block

A new stimulation pattern for evaluation of intense neuromuscularblock (post-tetanic burst (PTB)) was compared with post-tetanictwitch (PTT) during spontaneous recovery from vecuronium-inducedneuromuscular block. Thirty adult patients were allocated totwo equal groups and we measured times from administration ofvecuronium 0.1 mg kg^–1 to return of PTB and PTT responses,and evoked responses to PTB and PTT stimuli. For PTB stimulation,a 50-Hz tetanus was applied at 50 mA for 5 s, and after a pauseof 3 s, a 50-Hz burst stimulation was applied, consisting ofthree impulses at 50 mA. PTB stimuli were delivered every 5min. Similarly, PTT consisted of a tetanus, a 3-s pause andone single twitch stimulation repeated every 5 min. Time toreturn of the PTB response was significantly shorter than thatof PTT (mean 23.7 (SD 7.9) compared with 30.7 (7.0) min) (P= 0.0160), although evoked responses to PTB did not differ significantlyfrom those of PTT throughout recovery from vecuronium-inducedneuromuscular block. This study suggested that PTB was moresensitive in evaluating intense neuromuscular block than PTT.(Br. J. Anaesth. 1995; 74: 293–295)