[Use of magnesium sulfate during resection of pheochromocytoma]

A 75-year-old woman was scheduled to undergo resection of pheochromocytoma under general and epidural anesthesia. Continuous infusion of magnesium sulfate was initiated at the time of tracheal intubation and was terminated at the tumor resection. Intraoperative blood pressure and heart rate were stable, but blood pressure rose above 160 mmHg when the tumor was handled. Hypertension caused by the tumor manipulation was successfully treated with intravenous nicardipine. Following the tumor removal, reduced blood pressure was treated with dopamine and norepinephrine. After the operation, spontaneous respiration did not appear until 120 minutes following the last vecuronium injection. Although neuromuscular blockade was reversed with neostigmine and atropine, muscle tone was not restored and satisfactory spontaneous respiration was not obtained. One hour later the patient was extubated. Intraoperative use of magnesium sulfate provides adequate hemodynamic stability for resection of pheochromocytoma, but may cause prolonged neuromuscular blockade. Monitoring of neuromuscular function should be essential and reduction of ve curonium dose should be considered on using magnesium sulfate intraoperatively.