We Stopped an MH Crisis in Its Tracks

You never know how your staff will respond to a rare but potentially deadly malignant hyperthermia (MH) event until it actually occurs. When we found ourselves facing a recent crisis, our staff stepped up in a major way — and what we learned from the incident could help your team's response efforts if they ever wind up in a similar situation.

Like many MH emergencies, there weren't any early warning signs. From all outward appearances, the patient was the ideal candidate to anesthetize. At 22 years old, he was about to undergo surgery to remove a malignant scalp tumor. He was otherwise healthy, did not take any medications and had no allergies. It took about 45 minutes from the induction of anesthesia to get the patient positioned and ready for surgery.

Then it happened.

Just before the initial skin incision was made, the patient started to develop seizure-like movements. His muscles became rigid, his heart rate increased suddenly from 70 to 120 beats per minute and end tidal carbon dioxide quickly rose from 35 mmHg to 70 mmHg. The anesthesia fellow noticed the early warning signs of MH and informed the staff anesthesiologist, who was also present in the room. The staff anesthesiologist in turn confirmed the onset of MH and immediately started the treatment protocol for which our staff had been trained.

I was called into the room, where I arrived within two minutes to find out my colleagues had already appropriately managed the situation. Timing is critical any time an MH situation is in play. From the onset of the first sign of trouble until the first dose of dantrolene was given, it took only nine minutes to stabilize the patient. A lot happened during that time. To give you some perspective, here's a minute-by-minute account of everything that occurred:

09:19 The anesthesia fellow noticed the first signs of MH: sudden onset of "seizure-like" tremors, tachycardia and rapid increase of end-tidal carbon dioxide.

09:21 The anesthesiologist had a strong suspicion of an MH crisis, and discontinued and scavenged sevoflurane. At that moment I received a phone call from the OR coordinator.

09:23 I arrived in the operating room. The MH cart was already in the room, the anesthesia assistants had just installed carbon filters in the breathing circuit and dantrolene vials were out of the box. Although MH signs seemed to be resolving, I confirmed that IV dantrolene was still indicated and recruited every available member from the OR team (the surgeon and his assistant, three OR nurses, the anesthesia coordinator and myself) for reconstituting the dantrolene. We grabbed one vial each for a total of seven vials (140 mg dantrolene) needed for the initial dose. The content from each vial (20 mg per vial) was reconstituted with sterile water and directly transferred into 60 mL syringes that were used to administer dantrolene through the patient's peripheral IV line — one after the other.

09:28 We finished administering the last syringe of dantrolene. The MH signs had resolved. The decision was made to postpone the procedure and transfer the patient to the ICU.

If it happens to you

There are three things you and your team should immediately do if you suspect your patient is experiencing MH:

• stop (and scavenge) the triggering anesthetic agent,
• call for help, and
• administer dantrolene.

Calling for help sounds simple, but its importance can't be overstated. During an MH crisis you will need an extra pair of hands to prepare the dantrolene while you are taking care of everything else.

In our case, the patient was transferred to intensive care and his surgery was postponed for two weeks. Genetic testing was sent immediately after the MH event and was negative. Therefore, we obtained a piece of muscle from the latissimus dorsi that the surgeon harvested for the scalp reconstruction during his re-scheduled surgery, and we confirmed by the caffeine-halothane contracture test that our patient was indeed MH-susceptible.

We usually hold morbidity and mortality meetings whenever there is a serious complication in the OR in order to review what could have been done better. We did not hold any formal meeting to discuss this MH incident, as the outcome was favorable. Nevertheless, all team members shared their satisfaction with how the case was handled, which encouraged us to maintain our current response protocols.

The entire incident reinforced the importance of regular, realistic training. Our staff performs in-service teaching and hands-on drills at least once a year. The teaching and drills involve reviewing the basics of MH diagnosis and treatment, as well as getting familiarized with the crisis response workflow, the contents of the MH cart and preparing dantrolene for administration.

Even though this case ended with a favorable outcome, I think it taught the staff valuable lessons on the importance of preparedness, early recognition and prompt treatment. Because we were ready, we prevented a crisis from becoming a catastrophe. OSM