Microcalorimetric studies in malignant hyperpyrexia susceptible individuals.

In an attempt to develop a diagnostic test for malignant hyperpyrexia (MH) without the need for open muscle biopsy, we have investigated the change in heat production brought about when platelets and muscle are exposed to halothane and caffeine. Halothane 3% caused platelet aggregation, which was itself associated with heat production. Caffeine 4 mmol litre-1 decreased heat production in platelets from both MH susceptible and non-susceptible individuals. Muscle exposed to 4% halothane showed an increase in heat production in both types of tissue. There were no significant differences in heat production between MH-susceptible and non-susceptible tissue in any of the tests.