TGI MH Friday, April 2, 2021
Rüffert H, et al. Consensus guidelines on perioperative management of malignant hyperthermia suspected or susceptible patients from the European Malignant Hyperthermia Group. Br J Anaesth. 2021 Jan;126(1):120-130. doi: 10.1016/j.bja.2020.09.029. Epub 2020
In today’s issue of TGI MH Friday, I’ll summarize a recent update from the European Malignant Hyperthermia Group on how to manage known or suspected MH susceptible patients when they present for surgery. There’s nothing new or surprising about their recommendations, but it’s always good to review once in a while (especially on a Friday when our brains are slipping into weekend mode).
Rüffert et al. used the Delphi method (i.e., the formalized consensus process of successive iterations of expert opinion when not enough scientific evidence is available) to come up with a variety of recommendations for optimal preparation and management of these patients. The paper and the figure that I’ve reproduced below goes into more detail, but here are their core recommendations:
· Pretreatment with dantrolene is not indicated.
· Prepare the anesthesia machine by either using a machine that has never been exposed to volatile anesthetics or flush the gases out using at least 10 mL/min according to the manufacturer or expert recommendations (Table 2 in the paper provides specific details).
· Use a brand-new anesthesia circuit and soda lime prior to machine flushing.
· If available, attach charcoal filters to the inspiratory and expiratory limbs of the anesthesia circuit and flush for 2-3 minutes.
· Remove the vaporizers. Some places will routinely put tape over them to remind the anesthesia provider not to use them, but this isn’t foolproof. I heard of a case where the anesthesia tech was urgently called away while in the middle of doing this, forgot to return to finish the taping, and the MHS child accidently received sevoflurane for a short time until the team realized it (luckily did well).
· After charcoal filters are placed and breathing circuit and soda-lime canister are changed, usual fresh gas flows can be used with a minimum of 1 L/min.
· Use only trigger-free anesthetics, essentially anything except volatile anesthetics and succinylcholine. Anything else you can think of is safe.
· No additional monitoring is required, over and above the usual monitors chosen for that patient.
· No preoperative or postoperative labs are necessary, other than those the patient was going to get anyway.
· Outpatient anesthesia is allowed. The authors here do not distinguish between outpatient anesthesia in a hospital facility and a free-standing surgi-center (ASF). To me, it makes sense that known MHS patients given a non-triggering technique in a free-standing center would be inherently safer. After all, you already know they are MHS. It’s the patients that you don’t know are MHS that are at risk if given a volatile anesthetic far from a tertiary care center. But, many facilities, including my own, specifically exclude MHS patients from having elective surgery at the ASF, mainly for reasons of throughput. On a busy day with tubes and tonsils, the last thing you want to do is to stop the momentum by having to prep the machine and make up the propofol infusion pump.
· Recovery and discharge criteria are the same as for any other non-MH susceptible patient.
I hope everyone has a relaxing and baseball-filled weekend (#LGM) and for those of you taking the weekend calls, hope you get some down time to watch your favorite team. And if you love reading PAAD every day, send to all your friends.