[Anesthetic management of a patient with dermatomyositis--clinical observation of the effect of muscle relaxants].

A 58 year old woman suffering from dermatomyositis underwent elective surgery for spinal caries. Concerning the anesthetic management of patient suffering from dermatomyositis, there is little information on the appropriate use of muscle relaxants. It is generally suspected that the patient is sensitive to nondepolarizing muscle relaxants. Anesthesia was with oxygen-nitrous oxide and fentanyl. Pancuronium 6 mg was given intravenously after awake intubation and an additional dose of 2 mg was given after 7.3 hours. During anesthesia neuromuscular function was monitored by neuromuscular transmission monitor (Datex Relaxograph). Duration of neuromuscular block was defined as the time for the twitch height to recover from total paralysis to 25% of the control value. Duration in this patient was 3.1 hours and this was longer as compared with the values of 1.1-1.8 hours obtained in 7 control patients. It is suggested that a usual dose of muscle relaxants results in a relatively higher effect in the patients with dermatomyositis because of their diminished muscle mass. The anesthetist should be careful in using muscle relaxants. The muscle relaxants should be given to such a patient with monitoring closely the neuromuscular function using a neuromuscular transmission monitor.