• Anesthesia;
  • Calcium;
  • Pig;
  • Skeletal Muscle

Background: The efficacy of intravenous (IV) administration of azumolene (Az), an analogue 30-fold more soluble than dantrolene, on pigs susceptible to malignant hyperthermia (MH) is incompletely understood.

Objective: To evaluate efficacy of Az on MH crisis in pigs.

Animals: Eight normal (MHN) and 7 susceptible to MH (MHS) pigs (Landrace × Large White × Pietran).

Methods: Prospective, laboratory trial. Hypermetabolic crisis was observed in MHS pigs, but not in MHN pigs, after a combined administration of inhaled halothane (1.5%) and IV injection of succinylcholine (SCh; 2.5 mg/kg). Susceptibility was confirmed using a caffeine and halothane contracture test. Az was administered 15 minutes after administration of SCh.

Results: Respiratory acidosis (pH 7.16 ± 0.02; Pco2, 46.2 ± 9.1 mmHg, HCO3, 22.5 ± 2.3 mmol/L), fever (38.2 ± 1.1°C), cardiac arrhythmias, and muscle contracture were observed in MHS pigs. MHS pigs (n = 5) treated with Az (2 mg/kg IV) survived the crisis with attenuation of signs (pH 7.30 ± 0.10; Pco2, 36.3 ± 4.5 mmHg; HCO3, 22.9 ± 2.3 mmol/L) and recovery of normal muscle tone and cardiac rhythm.

Conclusions and Clinical Importance: Az represents a possible substitute for dantrolene to reverse MH crisis in susceptible pigs.