MALIGNANT HYPERTHERMIA

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I recently reviewed a case where the patient arrested during transport from the Operating Room and due to lack of documentation it was not initially clear whether the patient had been monitored during the transport.  I was asked to review the case to determine, essentially, if the standard of care had been breached during transport.  Immediately, upon review of the medical record, I determined that the patient had indeed been monitored during the transport, but even if they had not been monitored, the arrest had been handled appropriately with the correct medications given.  A code sheet was not found within the medical record available for review but the medication sheet indicated the medications administered and the times of these administrations. There was also a narrative regarding the rhythmic events of the code event.  So I immediately wondered “why did the patient arrest”?  I quickly noticed, in a cursory look at the anesthesia record where the medications were documented, that the patient had significant hypotension, significant tachycardia up to 200 beats per minute, inability to obtain pulse oximetry readings in the last 45 minutes of the case; a 0.1 degree rise in temperature every 5 minutes until the temperature plateaued at 39.5 (103.1) and elevated ETCO2 (end-tidal CO2).  I cannot get into what the surgery was but can say that there were no obvious infectious issues present during the surgery; and subsequent blood cultures were all negative.

Malignant hyperthermia (MH) is a potentially fatal, inherited disorder usually associated with the administration of certain general anesthetics and/or the drug succinylcholine.  The prevalence of MH related to exposure to anesthesia has been estimated at 1 per 100,000 surgical inpatient procedures, and constitute 1% of all anesthesia mortality for the years 1999 to 2005.  The signs of Malignant Hyperthermia include muscle rigidity, tachycardia, high body temperature, muscle breakdown and increased acid content.   Another diagnostic tool for MH is unexpected cardiac arrest in pediatric patients.  Immediate treatment with the drug dantrolene usually reverses the signs of MH (What is MH?, n.d.).guidelines_for_malignant_hyperthermia_treatment_f_600x200

The MH Association of the United States now recommends core temperature monitoring for all patients given general anesthesia lasting more than 30 minutes.  The problem is that one then needs to recognize the possibility of MH occurring and treat the patient appropriately.  The optimum scenario is that the surgeon can halt the procedure as soon as possible but that is not always possible.  If surgery cannot be halted then the anesthesiologist must continue anesthesia while utilizing non-triggering IV anesthetics such as IV sedatives, narcotics, amnestics, and non-depolarizing neuromuscular blockers as needed.  Also a blood gas needs to be obtained to determine the degree of metabolic acidosis.  Cooling of the patient should occur if the core temperature is > 39 degrees C, or less if rapidly rising.  Glucoses should also be checked hourly (this patient had a glucose of 17 when blood work was done (for the first time) after a successful resuscitation (What is MH?, n.d.).

Complications associated with MH include (this patient had a number of these complications):

  • Change in consciousness level/coma.
  • Cardiac dysrhythmias and dysfunction.
  • Pulmonary edema.
  • Renal dysfunction.
  • Disseminated intravascular coagulation.
  • Hepatic dysfunction.
  • Muscular weakness.
  • Compartment syndrome(What is MH?, n.d.).

When reviewing a medical record always keep in mind that you are the one with the medical knowledge and your function is to help unravel the medical mystery within any given case. A case may not go in the direction that the attorney was thinking, but that does not mean that there was not a breach in the standard of care in another area.  If, as in this case, you have questions about why something occurred (such as this patient suddenly and unexpectedly arrested) keep your eyes and mind open to any facts that seem out of place.

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  1. Barb Hoffman

    Thank you for this interesting article. Helpful and educational.

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