title: Estimate of the relative risk of succinylcholine for triggering malignant hyperthermia.
abstract: BACKGROUND
  Facilities with volatile anesthetic agents stock dantrolene for the treatment of malignant hyperthermia (MH). The availability of dantrolene at these facilities satisfies cost-utility norms even for sites with as few as 1 anesthetic per workday, based on the overall incidence of MH per anesthetic. We considered the stocking of dantrolene at facilities with succinylcholine alone (i.e., where volatile anesthetics are not available), by using registry data and estimates of the frequency of administration of succinylcholine during anesthesia. We determine the magnitude of the relative risk of the administration of succinylcholine for triggering MH.
  
  
  METHODS
  The relative risk of triggering MH by succinylcholine versus volatile agents was calculated using data from 2 sources. The ratio of the number of cases of MH among patients receiving succinylcholine to number among patients not receiving succinylcholine was estimated from the previously published cohort of 284 cases of MH from the North American MH Registry of the MH Association of the United States (MHAUS). The percentage of anesthetics with succinylcholine was estimated using anesthesia information management system data from a typical North American hospital comprising tertiary operating rooms, obstetrics unit, ambulatory surgical center, and endoscopy and radiological suites.
  
  
  RESULTS
  The relative risk of MH with versus without succinylcholine was 19.6 (lower 95% confidence limit > 16.1). Limiting to cases with volatile anesthetics, the relative risk was 9.1 (>7.5). Both relative risks exceed 1.0 (P < 0.0001). Because more than half of the reported cases of MH included the use of succinylcholine, the relative risk exceeded 1.0 provided fewer than half of anesthetics in North America included the use of succinylcholine. The incidences of succinylcholine use at the hospital were 5.8% and 11.6% for all anesthetics and for anesthetics with volatile agents, respectively.
  
  
  CONCLUSIONS
  Our results provide no insight into the triggering mechanism for MH (i.e., succinylcholine could in isolation have an extremely low incidence of inducing MH, yet markedly increase the risk when administered in combination with volatile anesthetics). Until more epidemiologic data are collected and analyzed, having dantrolene available, where succinylcholine may be used, is reasonable, and this practice should be maintained.
authors.affiliation: Division of Management Consulting, Department of Anesthesia, University of Iowa, 200 Hawkins Dr., 6JCP, Iowa City, IA 52242, USA. Franklin-Dexter@UIowa.edu
authors.forename: Franklin
authors.initials: F
authors.lastname: Dexter
authors.forename: Richard H
authors.initials: RH
authors.lastname: Epstein
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Wachtel
authors.forename: Henry
authors.initials: H
authors.lastname: Rosenberg
mesh_terms: D000328:Adult; D000465:Algorithms; D000773:Anesthesia, Obstetrical / Q000009:adverse effects / Q000379:methods*; D018685:Anesthetics, Inhalation / Q000009:adverse effects; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008305:Malignant Hyperthermia / Q000453:epidemiology* / Q000209:etiology*; D009467:Neuromuscular Depolarizing Agents / Q000009:adverse effects*; D011247:Pregnancy; D018570:Risk Assessment; D013390:Succinylcholine / Q000009:adverse effects*
chemical_list: D018685:Anesthetics, Inhalation; D009467:Neuromuscular Depolarizing Agents; D013390:Succinylcholine