Perioperative anaphylaxis in Malaysia: A nine-year retrospective study.

Diagnosis of perioperative anaphylaxis (POA) and identification of causative agents remain challenging. This study aimed to describe the estimated incidence, characteristics and causative agents of POA in Malaysia. This is a retrospective review of all cases of suspected POA referred to the only anaesthetic allergy centre in Malaysia from March 2014 to December 2022. One hundred and ninety patients with suspected POA of Grade 2 and above were included. Data on clinical presentation, severity, management, serum tryptase and subsequent allergy workup (including skin and serum testing results) of these patients were extracted from the database. Dynamic tryptase was elevated in half of the cases where tryptase results were available and skin tests were positive in 96% of these cases. Skin testing was positive in 113 patients (60%) overall, and more than 70% of Grades 3 and 4 anaphylaxis cases. Neuromuscular blocking agents (NMBAs) and antibiotics were the most commonly identified causative agents (27.4% and 23% respectively). The commonest NMBAs were rocuronium and atracurium, both commonly cross-reacting with cisatracurium. The overall cross-reactivity rate among NMBAs was 58%. For antibiotics, the commonest causative agents were cefuroxime, ceftriaxone and amoxicillin/clavulanic acid. Using these data, the estimated incidence of Grades 2-4 POA over this period in Malaysia was approximately 1 in 30,000 anaesthetics. However, owing to the voluntary nature of reporting, it is possible that this is an underestimate, particularly in relation to some milder Grade 2 cases which may have gone unrecognised or unreported.