To the Editor:
We read with interest the study by Larach et al.,1 which performed extensive and complex analyses of three databases (i.e., Multicenter Perioperative Outcomes Group, the North American Malignant Hyperthermia Registry, and the Anesthesia Closed Claims Project) as well as performed a systematic review of literature. One of the conclusions of the study was that succinylcholine alone without volatile anesthetics may trigger malignant hyperthermia (MH). The authors seem to allude that this finding negates the Society for Ambulatory Anesthesia recommendation2 that permits Class B ambulatory facilities to stock succinylcholine for rescue of laryngospasm without stocking dantrolene. However, the Larach et al. study1 has significant limitations, particularly the fact that the analyses did not include data from Class B facilities or the use of succinylcholine for laryngospasm. The succinylcholine dose used for situations assessed in this study (i.e., possible difficult airway or electroconvulsive therapy) is generally much higher, and extrapolating the conclusions to low-dose (20 to 30 mg) succinylcholine commonly used to treat laryngospasm may be inappropriate. Of note, there are no reports of MH with low-dose succinylcholine. Also, as stated in the accompanying editorial by Hopkins,3 “the evidence presented in this article is insufficient to convince me that succinylcholine in the absence of volatile anesthetics can trigger a life-threatening progressive hypermetabolic response in MH–susceptible patients...”
Class B facilities provide for minimally or moderately invasive procedures not requiring general and/or regional anesthesia. These facilities, which are growing in number, typically do not stock dantrolene because they do not use (or have the ability to use) volatile anesthetics. To avoid the costs associated with carrying and replacing dantrolene, they often elect not to stock succinylcholine, as its presence is perceived to mandate the availability of dantrolene. Given that the use of succinylcholine for laryngospasm is under reported, although there is a high likelihood of overdiagnosis of MH, the prevalence of MH is credibly significantly lower than the incidence of laryngospasm, which makes this a significant patient safety issue. The Society for Ambulatory Anesthesia position statement acknowledges this reality. Therefore, offering the alternative to stocking succinylcholine without dantrolene is prudent from patient safety and cost-effectiveness perspectives.
In summary, the evidence presented in the Larach et al.1 study is not enough to contradict the extensive arguments put forth in the pragmatic Society for Ambulatory Anesthesia recommendations.2 In the era of escalating healthcare costs and changing surgical environments, any prudent guideline should balance the potential benefits of a recommendation with costs and risk mitigation. It should also be noted that the Society for Ambulatory Anesthesia recommendation does not extend to the pediatric age group and facilities that provide inhalation anesthesia or use of succinylcholine during induction of general anesthesia. Furthermore, this recommendation emphasizes precautions such as the need for MH drills and transfer arrangements.
Dr. Joshi has received honoraria from Pacira Pharmaceuticals (Parsippany, New Jersey) and Baxter Pharmaceuticals (Deerfield, Illinois). The remaining authors declare no competing interests.