Post Operative Procedure

Excerpt taken from "Guide to Malignant Hyperthermia in an Anesthesia Setting, Preventing Malignant Hyperthermia"

If the anesthetic course has been uneventful, with anesthetic drugs that do not trigger MH, continue to monitor vital signs in the PACU for at least one hour. Perioperative dantrolene is not necessary if there has been no evidence of hypermetabolism or rhabdomyolysis.

After outpatient surgery, the susceptible patient may be discharged on the day of surgery if the non-triggering anesthetic has been uneventful. A minimum period of 1 hour in PACU monitoring vital signs at least every 15 minutes and an additional 1 hour in phase 2 PACU/step down is recommended.

Consider using a chemstrip to document the absence of myoglobin.

If MH has occurred: Treat and monitor the patient in an ICU for at least 36 hours. 

DANTRIUM^®/REVONTO^®: After initial resolution of MH, if the physiologic and metabolic abnormalities of MH recur administer additional intravenous boluses up to a cumulative dosage of 10 mg/kg. Continue IV dantrolene for at least 24 hours, titrated to alleviation of hypermetabolism (hypercarbia or hyperthermia), muscle rigidity, tachycardia, acidosis, and elevated CK levels. Suggested dantrolene dosage is at least 1 mg/kg q 4 to 6 hours IV by either bolus or continuous infusion.

RYANODEX^®– After initial resolution of MH, if the physiologic and metabolic abnormalities of MH recur, administer additional intravenous boluses up to a cumulative dosage of 10 mg/kg. Continue IV dantrolene for at least 24 hours, titrated to alleviation of hypermetabolism (hypercarbia or hyperthermia), muscle rigidity, tachycardia, acidosis, and elevated CK levels. Suggested dantrolene dosage is at least 1 mg/kg q 4 to 6 hours IV by either bolus or continuous infusion.

• Monitor the patient’s coagulation status, watching for Disseminated Intravascular Coagulation Syndrome.
• Look for myoglobinuria and treat as needed. If myoglobinuria develops, maintain urine flow of at least 2 ml/kg/hr. A quick test for myoglobinuria is to test the urine via hema test strip. If there is a positive reaction for blood and no RBCs are visible microscopically, myoglobinuria is likely.
• Monitor potassium and CK levels q 8 hours. CK elevation may not be apparent for several hours. Use potassium-containing solutions with caution.  
• Monitor urine output.

Report this anesthetic complication on the AMRA form to the MH Registry of MHAUS. Printable PDF forms are available online at in our registry area, or by contacting:

Alert the family to the dangers of MH in the other family members. Refer family members for testing at the nearest MH Diagnostic Testing Center. See our testing page for a list of MH Diagnostic Testing Centers.  Individuals who experienced fulminant MH episodes should have blood sent for genetic screen of the entire RYR1.