Residual curarization in the recovery room after vecuronium

We have investigated residual block after anaesthesia which included the use of the neuromuscular blocking agent vecuronium but no anticholinesterase, in 568 consecutive patients on admission to the recovery room. The ulnar nerve was stimulated submaximally using TOF stimulation (30 mA). Postoperative residual curarization was defined as a TOF ratio <0.7. Of the 568 patients, 239 (42%) had a TOF <0.7 in the recovery room. These patients had received a larger cumulative dose of vecuronium than patients who had full recovery (mean 7.7 (SD 3.6) mg vs 6.2 (2.7) mg; P<0.05) and a shorter time had elapsed since the last vecuronium dose (117 (70) min vs 131 (80) min; P<0.05). Of 435 patients whose trachea was extubated, 145 (33%) exhibited inadequate recovery from neuromuscular block Six of these had one or no response to TOF stimulation and were reintubated. In the remaining 139 patients, neuromuscular block was successfully antagonized. Only 20 patients (3.5%) remembered TOF stimulation when questioned 2 h later in the recovery room, and discomfort associated with it was assessed using a visual analogue scale before discharge. We conclude that it is necessary to antagonize residual block produced by vecuronium.