Xenon does not induce contracture in human malignant hyperthermia muscle

Area of Science:

• Anesthesiology
• Pharmacology
• Human Physiology

Background:

• Malignant hyperthermia (MH) is a severe pharmacogenetic disorder of skeletal muscle.
• Potent inhalational anesthetics can trigger MH episodes in susceptible individuals.
• The safety of xenon as an anesthetic in MH-susceptible patients remains largely uninvestigated.

Purpose of the Study:

• To evaluate the safety of xenon as an anesthetic agent in patients susceptible to malignant hyperthermia.
• To compare the effects of xenon, halothane, and caffeine on muscle tissue from MH-susceptible and MH-negative individuals.

Main Methods:

• Muscle specimens were obtained from 31 individuals referred to the MH Unit of the University of Ulm.
• Thirteen individuals were classified as MH susceptible and 18 as MH negative.
• The effects of 70% xenon, halothane, and caffeine on muscle tension and twitch response were measured.

Main Results:

• Xenon (70%) did not induce an increase in baseline tension in any MH-susceptible muscle specimen.
• Halothane and caffeine, however, did increase baseline tension in susceptible muscle.
• A transient increase in evoked twitch response was observed in both MH-susceptible and normal specimens with xenon, indicating an MH-independent mechanism.

Conclusions:

• Xenon, at concentrations up to 70%, appears to be a safe anesthetic for MH-susceptible patients.
• Xenon does not trigger the hypermetabolic response associated with malignant hyperthermia.
• Further clinical studies are warranted to confirm the safety and efficacy of xenon anesthesia in this patient population.