[Application of bispectral index (BIS) monitoring to anesthetic management of posterior spinal fusion in a patient with Duchenne muscular dystrophy].

A 12-year-old boy with Duchenne muscular dystrophy underwent posterior spinal fusion for progressive scoliosis. Preoperative evaluation was focused on respiratory function as well as cardiac function, which revealed markedly reduced respiratory reserve (FVC 0.77 l, %FVC 25.9%, FEV1.0 0.48 l, %FEV1.0 62%) and well-preserved biventricular function. A possible association between malignant hyperthermia and Duchenne muscular dystrophy has been documented. Thus anesthesia was administered without triggering agents. Propofol and fentanyl were used for induction and maintenance of anesthesia, and the patient was ventilated with O2-nitrous oxide mixture. The anesthesia machine, prepared by using a disposable circuit and fresh CO2-absorbent and disconnecting the vaporizers, was flushed with O2 at a rate of 10 l.min-1 for 20 minutes before use. A small dose of vecuronium was administered while monitoring the train-of-four ratio. The bispectral index (BIS) was utilized to optimize the depth of anesthesia so that the wake-up test could be performed promptly on surgeon's request while avoiding the intraoperative awareness. The BIS was helpful in continuously assessing the wakening process. BIS increased from 40's to 80's in 15 minutes after discontinuation of propofol and nitrous oxide during the test. The patient was kept under close observation postoperatively without any sign of malignant hyperthermia.