MALIGNANT HYPERTHERMIA INVOLVING THE ADMINISTRATION OF DESFLURANE

Purpose: This report describes an episode of malignant hyperthermia (M H) in a ten year old boy receiving desflurane anaesthesia. Clinical fe atures: Following induction of general endotracheal anaesthesia with t hiopentone and succinylcholine, desflurane was administered for mainte nance of anaesthesia. Ten minutes after commencing desflurane administ ration heart rate and PETCO(2) increased to 165 bpm and 50 mmHg, respe ctively. Initially, the tachycardia was attributed to sympathetic resp onse secondary to desflurane. Desflurane was discontinued and isoflura ne was started. Minute ventilation was increased to decrease PETCO(2). Over the next five minutes, temperature increased to 38.4 degrees C a s the PETCO(2) increased to above 60 mmHg. Venous and arterial blood g ases were drawn which showed acidosis and hypercapnia. Temperature and PETCO(2) continued to increase, reaching peak values of 41 degrees C and 77 mmHg, respectively. Efforts to cool the patient were made. A to tal of 220 mg dantrolene sodium was administered iv. Following dantrol ene, the temperature increase and acidosis subsided. Heart rate and PE TCO(2) decreased to 130 bpm and 36 mmHg, respectively. The surgical pr ocedure was expeditiously performed. Postoperatively, in the Paediatri c Intensive Care Unit, a dantrolene infusion of 20 mg . hr(-1) was adm inistered for 12 hr. The trachea was extubated the following morning. Several days later, the patient underwent another surgical procedure w ithout complications using MH-safe anaesthetics. Conclusion: Onset of tachycardia in a patient receiving desflurane may initially be attribu ted to desflurane-induced sympathetic hyperactivity. This poses a clin ical challenge in the diagnosis of MH during desflurane anaesthesia.