◙ CODE BLUE It's all hands on deck whenever an MH alarm is sounded.

Malignant hyperthermia strikes fast and it strikes hard. Its subtle warning signs are detected by the most aware of anesthesia providers. Its only treatment demands precise coordination from a quick-thinking and quick-acting team comprised of every available member of the surgical staff. Here's what you need to know about this rare but deadly condition.

Warning signs and risk factors
According to the Malignant Hyperthermia Association of the United States, MH is an inherited disorder due to an acceleration of metabolism in skeletal muscle. We've never had an event here at Callahan Eye Hospital, but members of our staff and anesthesia providers, including me, have had experiences at other facilities. Thankfully, my brush with MH ended positively. An anesthesia provider noticed slight changes in the vital signs of a young female patient and a gradual increase in her core temperature. We were fortunate he asked the key question: "Is this an MH emergency?" When it was identified as the real deal, we immediately initiated treatment protocols.

There are several lessons here. First, this particular episode happened in the recovery area, so look for MH's warning signs until patients are discharged. Second, some individuals are more susceptible than others, but the complication can strike anyone at any time. Finally, it's critically important to take the early warning signs seriously to ensure interventions start as quickly as possible.

Let's take a closer look at MH's warning signs and risk factors. One of the earliest warning signs is masseter rigidity, which the anesthesia provider might notice during intubation. Providers must also closely watch for sudden or unusual rises in end tidal CO2 and decreases in arterial O2 levels. They might start to see signs of sinus tachypnea. The patient's core temperature will also start to creep up — as much as 1 ?F over a 15-minute period — although this is one of the last indications.

MH can strike patients who've had prior surgery with no adverse reactions to general anesthetics. It's an inherited trait, so patients with family histories of MH are at heightened risk. It's dominant in young men, pediatric patients and individuals with known musculoskeletal disorders such as muscular dystrophy.

Anesthesia providers routinely ask patients if they have a history of adverse reactions to anesthesia, but even individuals who've never experienced such issues aren't necessarily in the clear. When at-risk patients are identified, providers can plan anesthetics accordingly, avoiding the use of known triggering agents: the commonly used anesthetic gases sevoflurane, desflurane, isoflurane, halothane, enflurane and methoxyflurane, as well as the depolarizing muscular agent succinylcholine.

QUICK MATH
Calculate the Initial Dose in 3 Easy Steps

How much dantrolene should you give to a 180-lb. patient?

◙ Convert pounds into kilograms: 180 lbs./2.2 (conversion factor) = 81.81kg

◙ Multiply the patient's mass by 2.5mg/kg to determine the initial dose: 81.81kg x 2.5mg/kg = 204.52mg

◙ Determine how many vials you'll need to reconstitute: There are 20mg in each vial, so 204.52mg/20mg = 10.22 vials

Additional notes:

• Each vial is reconstituted with 60cc sterile water for injection, so you need 1 1,000L bag of sterile water for injection.
• The dantrolene bolus must be given within 10 minutes of the diagnosis of MH, and may be repeated every 5 minutes until the hypermetabolism stops or the maximum dose of 10mg/kg is given.
• Treatment should continue for 48 hours after the episode at 1mg/kg every 4 hours

— Marie Garner, RN, MSN, CNOR

It takes a team
The anesthesia provider was the guiding force in my positive experience because at that time, some 15 years ago, the nursing staff wasn't as knowledgeable or skilled in response protocols as today's nurses. Now we know that every surgical professional must have a baseline knowledge of what MH is and an appreciation of how difficult it is to treat it quickly and effectively.

We also know that saving a patient's life when MH hits demands a true team effort from literally every available staffer who can lend a hand. There are many critical assignments that need to be carried out, so assign specific roles to specific members of the team.

Every facility has its own response protocols, but this is what works for us. The anesthesia provider identifies the complication's onset and immediately asks the circulator to call a "Code Blue" and bring the MH kit and crash cart into the room. We have 1 MH kit to serve our 9 ORs. It's stored next to the code cart and checked daily to ensure the supplies are intact and current. The kit contains 36 vials of dantrolene, which is enough to administer 2 rounds of boluses for a patient of average weight; syringes with large-bore needles; 1,000L bags of sterile water; IV tubing and stopcocks.

The nurse at the main OR desk pages all available nurses and patient care assistants to join the response team. She also calls the MHAUS hotline (800-MH-HYPER) and patches the call through to the OR if the additional support is needed. MHAUS is a wonderful organization. The experts who man the hotline can guide your surgical team through the entire emergency, advising them what to look for and how to react after each step of the intervention is completed.

The extra hands who respond are needed to help reconstitute the dantrolene, the only specific treatment for MH. During an attack, says MHAUS, calcium levels in muscles increase, causing a corresponding increase in muscle metabolism, which causes the muscles to contract. Dantrolene directly interferes with the contraction by decreasing calcium levels in muscle cells.

Each vial of dantrolene has to be reconstituted with 60cc of sterile, preservative-free water, and it takes a total team effort to get it done quickly and effectively. We hook a 1,000L bag of sterile water to an IV tube attached to a stopcock through which we use a 60cc syringe to draw the needed amount as efficiently as possible. One nurse draws the sterile water and passes it to a second nurse, who injects it into a dantrolene vial. She then passes the vial to the next nurse in line, who rolls it in her hands to dissolve the mixture. Once the dantrolene is reconstituted, she passes the vial to the final person in line, who draws the drug into a syringe and hands it to the anesthesia provider for administration.

◙ DOWN THE LINE Reconstituting dantrolene for administration demands coordinated efforts and practice.

The anesthesia provider already knows the patient's weight, so he informs the mix team how much dantrolene is needed for the initial dose (see "Calculate the Initial Dose In 3 Easy Steps"). By the time the team gets the first round mixed and ready for administration, they start preparing another round, because the initial bolus is repeated every 5 minutes until a maximum dose is reached.

Other nurses man the code cart, place a foley catheter in the patient, run for bagged ice to place on the patient and make arrangements to transfer the patient to an acute care setting with adequate support staff for immediate observation in an intensive care unit.

Rehearsed responses
Practice your MH response at least annually at mandatory education sessions for the OR nurses, all your anesthesia providers, and the pre- and post-op nursing staff. Divide your staff into small groups for question and answer sessions about how to manage an MH crisis. Have members of each team assume roles — nurse, anesthesia provider, circulator — and give them scenarios to discuss. What would they do during a real emergency?

Throw a "mixing party" with your expired dantrolene. It's a valuable exercise for all members of your team, but particularly important for nurses who have never reconstituted the drug. They need the hands-on experience to understand how truly challenging the process is, and why so many people are needed to quickly prepare the medication for administration.