Impact of Closely Grouped, Iterative Exposures to Suxamethonium During ECT on the Sensitization to NMBA and the Development of Protective Antibodies

Acute per-anesthetic hypersensitivity reaction (HSA-PA) is a rapidly occurring systemic reaction following injection of a drug during anesthesia (mortality between 3 and 9%). The substances responsible for these reactions in France are Neuro-Muscular Blocking Agents (NMBA) in 60% of cases. The main mechanism mentioned is an immediate systemic hypersensitivity immune reaction (anaphylaxis). The mechanism of immunization to NMBA is not yet understood. Electroconvulsive therapy (ECT) is a long-standing therapeutic approach still widely used today, for its high efficiency, particularly in depressive syndromes resistant to antidepressants. It has an efficacy comparable (or even superior) to pharmacological treatments and improves the mortality associated with this disease. Treatment with iterative ECT sessions includes an attack phase with an average of 12 sessions over 4 weeks, with secondary spacing of sessions before switching to antidepressant treatment. These sessions are carried out in the operating room under general anesthesia, thanks to a hypnotic and a NMBA, suxamethonium, as recently recommended by the French Anesthesiology Society in 2020. ECT therefore represent an interesting model of iterative exposure of a relatively homogeneous population to a single highly sensitizing substance, which could make it possible to study the evolution of sensitization as a function of various factors, in particular cumulative exposure, for which no data is currently available.