Recognizing mH

The MH crisis is a biochemical chain reaction response, “triggered” by commonly used general anesthetics and the paralyzing agent succinylcholine, within the skeletal muscles of susceptible individuals.7,14

Signs and symptoms of MH include14:

  • Elevation of end-tidal carbon dioxide
  • Muscle rigidity
  • Tachycardia
  • Acidosis
  • Hyperthermia
  • Hyperkalemia

Other clinical signs include skin mottling, sweating, ventricular tachycardia, cola-colored urine, ventricular fibrillation, and cyanosis.14

An MH relapse can be fatal

Know the signs

Watch for an MH relapse by continuously monitoring patients following cessation of MH symptoms, because there is a 25% recrudescence rate. If an MH relapse occurs, administer RYANODEX® (dantrolene sodium) for injectable suspension by intravenous push starting with 1 mg/kg.7,16

Signs of MH relapse include16:

  • Increasing muscular rigidity in the absence of shivering
  • Inappropriate hypercarbia with respiratory acidosis
  • Metabolic acidosis without other cause
  • Inappropriate temperature rise

MHAUS recommends monitoring16:

  • ECG, ETCO2, minute ventilation, core temperature, urine output (with bladder catheter if necessary), and consider arterial and/or central venous monitoring if warranted by the clinical severity of the patient. Document muscle tone.
  • Follow continuously for the first 24 hours:
    • Heart rate
    • Respiratory rate
    • Core temperature
    • ETCO2 (if intubated)
    • Oxygen saturation
    • Muscle tone
  • Follow every 8 hours:
    • Blood pH and lactate
    • Serum potassium
    • Creatine kinase (until decreasing)

The window of time from recognition to administration of dantrolene is critical2,4

Consider the resources needed to prepare and administer dantrolene sodium at cumulative doses of 2.5 mg/kg to 10 mg/kg to a 100 kg patient.1,7

  Other dantrolene sodium formulations1,4-6,8 RYANODEX®1,7
Vials to be reconstituted 13 to 50 vials 1 to 4 vials
Volume of sterile water for injection being administered 750 to 3000 mL of sterile water for injection 5 to 20 mL of sterile water for injection
Time to reconstitution >22 minutes Less than 1 minute for reconstitution and administration
mg/per vial 20 mg dantrolene sodium per vial 250 mg dantrolene sodium per vial
Concentration 0.33 mg/mL reconstituted formulation concentration 50 mg/mL reconstituted formulation concentration

Only RYANODEX® allows for rapid response with 1 vial, by 1 provider, in less than 1 minute1

Indication and Important Safety Information