The closest that many surgical facilities will come to a malignant hyperthermia emergency is their annual all-hands-on-deck drill. Ronald Litman, DO, FAAP, has experienced more than drills, more than once. As a hotline consultant for the Malignant Hyperthermia Association of the United States (mhaus.org) for more than 15 years and as the group's medical director since 2013, he's witnessed how OR teams react when the warnings become reality and guided them through the potentially fatal complication. According to Dr. Litman, a professor of anesthesiology and pediatrics at the Perelman School of Medicine at the University of Pennsylvania and an anesthesiologist at the Children's Hospital of Philadelphia, the key to an effective response is knowing what you're up against, as he told us in a recent interview.
- On the line with emergencies. The calls the hotline gets are all different. Sometimes they're handled calmly, in a focused way. Sometimes they're very chaotic. We get a fair share of real cases, about 1 to 3 a week, about 75 cases a year in North America. There may, of course, be more cases we don't get called on.
- Anticipating adverse events. We also get a lot of practical calls that are not emergencies, but are asking how to prepare. Another typical call with a difficult answer is whether a high-risk patient whose family is distant, and who doesn't have records available, and who hasn't been tested, is susceptible to MH. We tend to respond on the side of caution, that they are. The only way to know for sure, though, is the contracture test, which involves a muscle biopsy and which can only be obtained at 5 centers in North America. Susceptibility can only be ruled out if the test comes back negative.
- Warning signs of MH. Muscle rigidity in all extremities is a telltale symptom of malignant hyperthermia, especially when you've already administered a muscle relaxant. It can appear that they're shivering vigorously, but if they've been given a paralytic agent, they won't be able to shiver.
- Incorrect identification. Perhaps the most common misstep witnessed by hotline consultants is OR staff thinking it's MH when there are other causes for the symptoms they've observed. For example, hypoventilation causes end-tidal CO2 to rise. We get a lot of calls saying, 'We can't get the carbon dioxide down.' It turns out it's a problem that's ventilatory in nature, the endotracheal tube is clogged or too small.
- What about post-op fevers? We get calls involving patients with fevers in post-op recovery. That's almost never a sign of MH. Some patients do suddenly develop high temperatures after surgery, over 103 ?. There are many theories, and it's certainly alarming. There's good reason to think of MH, but almost none of the cases we've seen develop after surgery. Recovery room MH is almost unheard of.
- The perils of diagnosis. An incorrect MH diagnosis can put a patient at significant harm in the immediate present as well as over the course of a lifetime. Giving dantrolene is not innocuous. In a small vein, it can cause a blood clot. It can cause muscle weakness that could lead to breathing difficulties after surgery. Similarly, the risk of labeling patients as MH-susceptible when they're not is you can't tell if they're a case for sure. They'll need to be observed in the hospital, they're labeled for the rest of their life, they can't get volatile gas or succinylcholine. Since it's an inherited disease, all the people in their entire family are going to be implicated. It's a very serious decision. At the same time, however, you don't want anyone to miss it, to not treat it. And you never want to wait too long to react. This difficult diagnosis is the reason why the MHAUS hotline exists.
- A risk in response. You've got to be extremely aggressive in keeping the patient's temperature under control. But people overtreat hyperthermia. They continue the cooling methods with ice baths or cooling blankets even once the temperature has reached 38 ?C. By that point, you have to stop. Hypothermia is a real concern. If the patient gets too cold, they'll suffer other abnormalities. They'll stop metabolizing drugs, it'll delay their return to wakefulness, there's a higher risk of infection, they could suffer blood clots. Especially since they've been treated with dantrolene.
- Training the treatment. If you do simulations on at least a yearly basis, the process stays fresh in your mind, you can work out the kinks. Many providers will go their entire careers and never see an incident. But it's really important, getting everybody used to the treatment.