Use of vecuronium and doxapram in patients susceptible to malignant hyperthermia.

Neuromuscular blockade was obtained with vecuronium 108 micrograms kg-1 in 44 patients undergoing diagnostic muscle biopsy as part of an investigation of malignant hyperthermia (MH) susceptibility. At the termination of anaesthesia doxapram 1.43 mg kg-1 was given in an attempt to antagonize postoperative respiratory depression. Rectal, muscle and skin temperatures, blood lactate concentration and venous PCO2 were measured before, during and after anaesthesia. Susceptibility to MH was established by in vitro contracture tests according to the protocol of the European MH Group. Twenty patients were susceptible to MH (MHS), 19 were MH non-susceptible (MHN) and five MH equivocal (MHE). No adverse effects of the drugs were observed. There were no differences between the three groups in rectal or muscle temperature, blood lactate concentration or venous PCO2 at any time. Doxapram did not prevent an increase in postoperative PCO2. It is concluded that vecuronium and doxapram may be safely administered to patients susceptible to MH.