[The relationship between maintenance dose of vecuronium and the recovery time from the muscle relaxation].
We investigated the relationship between maintenance bolus dose of vecuronium bromide (Vb) and the recovery time measured by TOF Guard in patients anesthetized with isoflurane (1.2-2.0%)-N2O-O2 (GOI group, n = 19) and epidural anesthesia (2% mepivacaine) plus isoflurane (0.5%)-N2O-O2 (EPI group, n = 14). In both groups, anesthesia was induced with propofol 2 mg.kg-1 and Vb 0.1 mg.kg-1 and ventilation was controlled to keep end tidal CO2 between 35-40 mmHg. When the muscle relaxation recovered to 25% of train-of four ratio (TOFR), doses of Vb 0.06, 0.04 or 0.02 mg.kg-1 were administered. Recovery time to TOFR 25% at each Vb dose (T 0.06, T 0.04 and T 0.02 respectively) was observed. T 0.02, T 0.04 and T 0.06 in GOI group were 36.7 +/- 3.2, 50.7 +/- 4.3 and 60.7 +/- 5.02 min (mean +/- SE), respectively and those in EPI group were 42.6 +/- 2.53, 52.2 +/- 2.51 and 59.9 +/- 3.22 min, respectively. There were no significant differences in the recovery time between these two groups. In both groups, although the recovery time to TOFR 25% was prolonged significantly in proportion to the increasing doses of Vb, the increase did not correlate with the dose of Vb. We suggest that frequent administration of Vb 0.02 mg.kg-1 decreases the total amount of Vb to keep TOFR within 25%.