Always Prepared for Malignant Hyperthermia

Providers must be ready to act swiftly when MH is in play.

According to the Malignant Hyperthermia Association of the United States (MHAUS), malignant hyperthermia (MH) is a potentially fatal inherited disorder usually associated with the administration of certain general anesthetics and/or the drug succinylcholine.

Untreated, an MH event has a high fatality, somewhere in the 90% range; when properly treated, the mortality rate drops to 3-5%.

So how do you make sure your staff is prepared if an MH crisis does occur? In my experience, focusing on two essential measures is key: stocking a dedicated MH cart to be used during a crisis, and instituting realistic training to ensure your staff can act quickly and confidently if a real-life event ever takes place.

Essential supplies

Make sure you have an MH cart that is properly stocked, organized, labeled and conveniently located. You should also regularly check expiration dates every few months and restock as necessary. Check with your facility’s policies regarding who is responsible for checking the expiration dates, which should be done regularly. Nurses at the surgery center where I work excel in this area and consistently check the expiration dates.

It may sound silly or obvious, but make sure every drawer is clearly labeled with its contents. The first drawer should contain dantrolene, which is the agent that is used to treat MH. Currently two formulations of dantrolene exist. The drug acts as a reversal agent and is classified as a muscle relaxant that can help treat the symptoms of MH.

The formulation of dantrolene on an MH cart varies from facility to facility. While one formulation is less expensive, the drug comes in 20 mg vials that must be reconstituted with 60 mL of sterile water. A newer, more costly formulation is an injectable suspension of dantrolene sodium that comes in 250 mg vials but only needs to be reconstituted with 5 mLs of sterile water. If you’re using the 20 mg vials of dantrolene, MHAUS recommends stocking your cart with 36 vials, with each vial to be diluted at the time of use with 60 mL of sterile water. If you are using the 250 mg vials, make sure you have three vials of it available, each to be diluted at the time of use with 5 mL of sterile water for injection.

Your cart should contain plenty of saline and sterile water, as well as syringes and needles to draw it up. I prefer to have these items readily available in the second drawer. You also need IV fluid, a Foley catheter and potentially a central line just in case you need to do that. It doesn’t matter where you keep these items in the cart, as long as everything is properly labeled so you know exactly where to find them.

For a full list of everything that should be on your MH cart, click here.

Top-notch training

ALL HANDS ON DECK Your goal is to get this medication to the patient as quickly and as safely as possible before they go into cardiac arrest.

While I’m all for having each member of your team responsible for their own specific task or tasks during an MH event, this type of crisis doesn’t happen in a bubble.

At my surgery center, we have role cards with the definition of what each team member is supposed to do, but we also know we might not have all the roles filled at any given time. Therefore, it’s crucial to avoid a tunnel-vision mindset. For instance, don’t expect only certain members of your team to be trained on how to administer the dantrolene. When there’s a true MH event, it needs to be all hands on deck.

If the anesthesia provider is monitoring and managing the airway and putting the breathing tube in if the patient is not already paralyzed, they may be reconstituting it and directing it. But often, MH is a chaotic event because it can happen intraoperatively during the middle of surgery — or it could happen in the PACU during the recovery phase.

If it’s happening in the PACU area, chances are the patient has already extubated and is going through MH. Their muscles and jaw are very rigid and taut, making it difficult to secure the airway with an endotracheal breathing tube. In situations like this, we may ask the PACU nurse to start administering the medication, as my number one priority is to get that breathing tube in so we can oxygenate and ventilate the patient. If an MH event takes place in the OR, the anesthesia provider may be administering the first couple of doses and then call on the circulator and some extra pairs of hands to help out. If I need 10 vials, for example, I can have one or two people working on the vials as I slowly push it through the lines. Your goal is to try to get this critical rescue medication to the patient as quickly and as safely as possible before they go into cardiac arrest, which can happen within a minute.

Whether a patient is having a true MH event or exhibiting signs, someone from your team should always call the 24-hour MHAUS hotline at 1-800-644-9737.

Anybody from the OR or the PACU can call the hotline, but I always recommend that the call is placed on speakerphone. That way, the MH expert can guide your entire team, which is especially helpful if the event happens late at night when minimal staff are on-call.

I recommend that routine MH training be conducted every six months — or at least on an annual basis. If you have an influx of new hires or temporary staff at your facility, include MH training during the onboarding process. I find performing a mock MH simulation is extremely helpful in preparing your team for an emergency.

Anywhere where succinylcholine or inhalational agents can be administered, that team should be able to understand and identify potential symptoms of MH and how to treat it. It depends on the institution and the availability of high-fidelity simulation mannequins that can mimic the scenario versus just having staff members call an MH event. These types of training events are vital because they can help weed out any questions and insecurities your team may have.

Every second counts during an MH event, so even something as simple as making sure your team knows where the MH cart is located can make all the difference. OSM