[Prolonged neuromuscular blockade with vecuronium in patient with triple pregnancy treated with magnesium sulfate].

A 33 year-old parturient with triplet pregnancy underwent emergency cesarean section at 35 week of gestation under general anesthesia. The patient had received magnesium sulfate to prevent uterine contraction immediately before the cesarean section. Although serum magnesium value was not beyond therapeutic levels (3.3 mEq.l-1), the neuromuscular blocking effects with vecronium were strengthened. It was not likely that volatile anesthetic enhanced neuromuscular blockade produced by vecuronium because the onset time of vecuronium had already been faster than that in pregnant patients untreated with magnesium before she was exposed to isoflurane. In addition, it is possible that magnesium could interfere with postpartum uterine contractions because of its tocolytic properties. Magnesium sulfate therapy has several implications to anesthetic agents. We, anesthesiologists, should know about the biophysiological effects of magnesium and control the interaction between anesthetic agents and this electrolyte.