HONEST ASSESSMENT Your malignant hyperthermia response plan should be specific to your facility's resources, available manpower and location.

When you answer hundreds of calls made to the emergency hotline of the Malignant Hyperthermia Association of the Unites States (MHAUS), like I have, most questions fall into 1 of 3 categories.

Is this correct? Most involve surgical teams responding perfectly to an MH event that simply want confirmation that they're following proper protocols.

How much dantrolene? Other callers want to review the dosing amounts before administering it to stricken patients.

OMG! Where do we begin? Then there are the scary calls, the ones that keep me up at night. On the other end of the line I hear yelling, confusion and panic. No one is taking control of the situation because everyone is unsure of what to do next. I always think about how those surgical teams probably wished they'd known more about MH before walking into their ORs on those fateful days.

I'll tell you just what I tell these callers. If you suspect MH, err on the side of caution and move forward with the assumption that you're dealing with an actual episode. The potential risks of not treating the patient with dantrolene — hypoxia, cardiovascular collapse, heart attack, kidney failure and death — far outweigh the inconvenience of overreacting to a false alarm. Here are 10 other common questions we get at the MHAUS hotline.

1. Who's most susceptible to MH? MH-susceptible patients carry one or more gene mutations of skeletal muscle, which, when exposed to triggering agents, causes abnormal levels of calcium to be released in muscles. The muscles, which may or may not contract abnormally, experience an abnormal increase in metabolism and heat production. High metabolism increases CO2 production and drives increased respiration. High oxygen demand and CO2 production cause severe tissue hypoxemia and metabolic acidosis. Muscle cells are then depleted of adenosine triphosphate (ATP) and die, which releases excess amounts of potassium into the bloodstream. The influx of potassium into the bloodstream causes hyperkalemia and eventually cardiac arrhythmia.

2. What triggers MH? Common triggering agents include the volatile general anesthetics halothane, enflurane, isoflurane, desflurane and sevoflurane, and the muscle relaxant succinylcholine, which produces immediate intense paralysis so providers can treat life-threatening hypoxemia from airway obstruction.

3. What if we don't use inhalational agents? Patients can develop MH in response to succinylcholine alone. So even if you don't use inhalational agents, you still have to stock dantrolene if you carry the paralyzing agent to treat airway emergencies.

4. What are the early warning signs? Countless lives have been saved when astute providers recognized the signs of trouble — muscle rigidity, flushed skin, rising end-tidal CO2, abnormal heart rhythm, rapid breathing and rising core body temperature.

A rise in core body temperature was assumed to be a late-stage indicator, but recent data show it might in fact be one of the immediate presenting signs. Professional organizations strongly recommend that you monitor core body temperatures during any procedure involving triggering agents that's expected to last longer than 10 minutes.

READY TO ROLL Make sure needed supplies are current and easily accessible, because MH can strike any patient at any time and during any procedure involving triggering agents.

5. Who's responsible for recognizing a crisis? Every member of your surgical team must be able to recognize an event and implement life-saving protocols. In one case I helped manage on the MHAUS hotline, a nurse substituted for a colleague mid-procedure and, because of her fresh perspective, noticed an event occurring that had escaped detection by everyone else in the room.

6. What's the best way to prep for MH? Focus all your efforts on preparing dantrolene for administration and contact local emergency response services to transfer the patient to a local hospital as quickly as possible. Every member of the surgical team should have specific assignments that they master during practice sessions, so they react almost instinctually during an emergent situation. For example:

Surgeons. End the procedure as soon as possible and help reconstitute dantrolene.

Anesthesia providers. Stop the administration of inhalation agents, hyperventilate the patient with 100% oxygen, discontinue warming devices, initiate cooling and help administer dantrolene. After the initial dose (2.5 mg/kg) has been administered, they may need to give up to as much as, or more than, 10 mg/kg to stabilize the patient for transfer to the nearest hospital.

Nurses. Call for immediate help from all available staffers, retrieve the MH cart, coordinate the mixing of dantrolene, direct a designated staff member to call 911 and help place ice packs around the patient.

Additional staff members. Respond to requests for help, assist with obtaining supplies, help prep dantrolene and replenish the supply of ice that's cooling the patient.

7. Is it safe to treat at-risk patients in the outpatient setting? Yes, surgery can be performed on patients who are at risk of MH — those who've had an episode in the past or have closely related family members who have — as long as the surgical team reviews early warning signs and response protocols before the procedure, moves an MH cart stocked with dantrolene into the OR, avoids the use of triggering agents, and closely monitors the patient's end-tidal CO2, minute ventilation and core body temperature during the procedure and throughout the recovery phase.

8. Which dantrolene option is best? The 3 available preparations (Dantrium, Revonto and Ryanodex) appear to be equally efficacious and have been used to successfully reverse MH episodes. The average dose needed to treat a stricken patient is roughly 2.2 to 2.5 mg/kilo. Ryanodex, the newest preparation, comes in 250 mg vials and can be dissolved with 5 to 10 ml of sterile water. Dantrium and Revonto come in 20 mg vials and require 60 ml of sterile water for reconstitution. That's a time-consuming process that requires quite a bit of manpower.

Fewer vials of Ryanodex are needed to deliver the initial dose, but the agent is more expensive than the other options. Some facility leaders opt to stock the less expensive Dantrium and Revonto to safeguard against a rare event, and that's a rational argument, especially if your surgical team is big enough to reconstitute the formulations quickly and efficiently. Smaller outpatient centers with a limited amount of backup help might be better served with the more expensive Ryanodex, which can be mixed with less effort and in less time.

Regardless of which dantrolene product you stock, make sure the supply is current and there's enough to administer the stabilizing or typical maximum dose: 36 vials of Dantrium or Revonto, or 3 vials of Ryanodex.

9. What else should I stock in my MH cart? Store 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. Also stock basic supplies such as syringes, IV catheters, nasogastric tubes and Toomey irrigation syringes.

10. How common is MH? Not very. The incidence of anesthetic-related episodes of MH is between 1 in 15,000 in children and 1 in 50,000 in adults, according to MHAUS. They're rare events, to be sure, but can occur in patients who are unaware of their susceptibility or who have been previously anesthetized without incident. OSM