MOCK DRILL The best way to be prepared for an MH emergency? Mock drills, says Ron Litman, DO, medical director of the MHAUS hotline.

As the medical director of the Malignant Hyperthermia Association of the United States' 24-hour emergency hotline (800-644-9737), I've fielded every inquiry imaginable about the potentially fatal inherited disorder that can strike without warning. To help you better prepare for an MH episode, here are answers to the questions I'm asked most frequently.

1. What's the biggest key to emergency-response success?
Being prepared is the most important thing. First, make sure you have a well-stocked MH cart equipped with all necessary drugs and equipment to prevent and treat a crisis (see question 2 for more details).

Perform a mock MH simulation drill annually. As someone who's on the other side of the hotline, I can tell you that facilities that hold annual drills are noticeably calmer and more goal-directed during a real crisis.

You can purchase MH simulation systems or simply create your own mock drill. Set aside part of a day and have your staff walk through responding to a patient experiencing symptoms of MH. Practice calling the MHAUS hotline and reconstituting expired dantrolene to get the full experience of an actual emergency response.

During the mock drill, assign staff specific roles. If you work in a freestanding surgery center, establish a prearranged transfer plan to the closest hospital. Simply knowing which ER is nearby isn't enough. Communicate your plans with the nearest hospital and ensure that they have the supplies and capabilities to handle a transferred MH patient.

2. What supplies should always be on hand?
The most important component is dantrolene. To treat an MH episode, an initial dose of dantrolene at 2.5 mg/kg is recommended. Since some MH patients may require as much as 10 mg/kg dantrolene at the start of an episode, we recommend having at least 700 mg available. Note, though, that this is based on an average patient weight of 70 kg, which is lighter than many patients nowadays. For Dantrium/Revonto, this translates to a minimum of 36 vials on hand. For Ryanodex, it's a 3-vial minimum. Additionally, dantrolene always requires sterile water for reconstitution.

You also want to make sure your MH cart contains sodium bicarbonate, dextrose, calcium chloride or calcium gluconate, regular insulin, and refrigerated cold saline solution for IV cooling. These drugs are used to treat the deadly consequences of MH, including high potassium levels that can stop the patient's heart. Stock charcoal filters for your anesthesia machine, as well as basic supplies such as syringes, IV catheters, nasogastric tubes and Toomey irrigation syringes. Also have available basic nursing necessities and lab testing supplies for blood and urine analysis. For a complete list, visit mhaus.org.

BE PREPARED Ensure you have enough dantrolene, as well as cold saline, sterile water and other supplies, on hand to treat an MH episode.

3. Can MH-susceptible
patients undergo surgery at an ASC?
Yes. In fact, these cases are often safer than when you don't know if the patient is MH-susceptible, since you can plan accordingly.

Your anesthesia providers should anesthetize the patient without using the volatile gases that can trigger an episode: isoflurane, sevoflurane and desflurane. Most providers use IV propofol as an alternative. Providers will also want to avoid the use of succinylcholine, because that is also a known trigger.

Before surgery begins on an MH patient, the anesthesia provider should insert charcoal filters into the anesthesia machine's breathing circuit to purge it of residual anesthetic gases.

If an MH-susceptible patient successfully undergoes the surgery using non-triggering anesthetics, they may be sent home using your normal discharge criteria. While it may seem intimidating, known MH-susceptible patients can safely undergo surgery and general anesthesia in any type of outpatient facility.

4. A patient has a high fever in recovery. Could this be MH?
This is a common call we receive at the hotline. While MH is associated with several different symptoms — rigid muscles, flushed skin, a spike in end-tidal CO₂, abnormal heart rhythm, rapid breathing and brown or cola-colored urine — a high temperature is one of the more alarming ones for many healthcare professionals.

It may be (somewhat) comforting to know that it's not uncommon for patients to develop a high temperature after surgery. If your patient suddenly spikes a 104-degree fever in recovery, something other than MH is probably at play.

Post-op MH is extremely rare, and when it does occur, it happens only within a few minutes of turning off the anesthetic. If a patient develops a high temperature in recovery, first check for any of the other MH symptoms. Without muscle rigidity, heart arrhythmia or another associated symptom, MH almost certainly isn't occurring.

5. A pediatric patient was given sevoflurane and is now experiencing muscle rigidity. What do we do?
It can be very hard to distinguish MH and sevoflurane-induced myoclonus and muscle rigidity. Add to it that sevoflurane is often given to pediatric patients, and this quickly becomes a provider's worst nightmare.

One of the things we immediately tell facilities is to check the patient's end-tidal CO₂. Studies have shown that a high reading almost always accompanies MH. If the muscle rigidity is accompanied by high end-tidal CO₂ that is not responding to increasing ventilation, immediately begin the steps to treat MH. But if there are no other symptoms besides muscle rigidity, it is likely not MH. Remember to call the hotline if there are any doubts about whether you're facing an MH episode.

6. We don't use volatile anesthetic gases. We got rid of our succinylcholine. We don't need to have dantrolene on hand, right?
Technically, this is true — but that doesn't make it smart. Accrediting agencies require facilities to stock the right amount of dantrolene if they have anesthetic gas or succinylcholine on the premises. Recently, centers that use only intravenous anesthesia, like propofol, have gotten rid of their succinylcholine just to avoid the cost of dantrolene, which usually runs several thousand dollars every 2 years.

This move can have deadly consequences. Succinylcholine, which produces immediate intense paralysis, is the most important medication in the anesthesiologist's drawer because it can treat life-threatening hypoxemia from airway obstruction before brain damage occurs. You are much more likely to need succinylcholine to save someone's life than dantrolene. Don't skimp — make sure you stock succinylcholine and dantrolene to keep your patients safe.