HYPERKALEMIC CARDIAC-ARREST DURING ANESTHESIA IN INFANTS AND CHILDRENWITH OCCULT MYOPATHIES

In 1992, the Malignant Hyperthermia Association of the United States a nd The North American Malignant Hyperthermia Registry received reports of cardiac arrest in apparently healthy children given succinylcholin e, Using data from 1990 to 1993, this study analyzes: (1) etiology of all reported pediatric arrests and (2) whether survival was associated with certain patient or treatment variables, We reviewed retrospectiv ely all reports of pediatric (age <18 years) arrests occurring within 24 hours of anesthesia. Etiology of arrests and presence of myopathy w ere determined. Twenty- five patients (92% male, median 45 months old) arrested; 23/25 (92%) were scheduled for minor surgery. Before receiv ing a potent inhalational anesthetic (92%) and/or succinylcholine (72% ), these patients were evaluated by the anesthesiologist as being heal thy with no personal or family history of myopathy, Serum potassium du ring arrest was measured in 18/25 (72%) patients; hyperkalemia (mean [ K+] = 7.4 +/- 2.8, median 7.5 mmol/L) was detected in 13/18 (72%) pati ents, Postarrest resuscitations lasted a median of 42 minutes (range 1 0-296), Ten (40%) patients died, 1 (4%) is vegetative, and 14 (56%) re turned to baseline neurologic function, A previously unrecognized Duch enne dystrophy (n=8) or unspecified myopathy (n=4) was diagnosed in 12 (48%) patients, Eight of these 12 patients' ar rests were associated with hyperkalemia. Tell (40%) patients had no postarrest evaluation to exclude occult myopathy. No patient or treatment variables were stati stically associated with survival. We conclude that, whenever possible , pediatricians should evaluate their patients (especially male infant s and children) preoperatively for the presence of occult myopath. Dur ing perianesthetic resuscitations, the pediatric advanced life support protocol should be modified to detect and treat hyperkalemia, a poten tially reversible state even after prolonged resuscitation efforts. Fo llowing anesthetic deaths, pathologists should examine body fluid elec trolytes and skeletal muscle for myopathy and dystrophin, If a preanes thetic creatine kinase screen for myopathy in male patients and restri ctions on succinylcholine had been used, 64% of arrests and 60% of dea ths might have been prevented. A formal prospective risk/benefit analy sis for preventive measures is needed.