Malignant hyperthermia triggered by heating in anaesthetized pigs.

Three malignant hyperthermia susceptible (MHS) and three normal Danish landrace pigs were heated using a water-heated mattress, warm blankets and warm intravenous saline during anaesthesia with barbiturate and 50% nitrous oxide in oxygen. The MHS pigs developed typical malignant hyperthermia (MH) at a rectal temperature of 41.0 +/- 0.7 degrees C, whereas the normal pigs tolerated heating to the same temperature without any ill effects. Haemodynamic and metabolic findings during MH were similar to those previously reported for anaesthetic-induced MH in pigs. Heat intolerance may thus be one factor in the genesis of MH.