Incidence and outcome of anaphylaxis in cardiac surgical patients

Introduction: Anaphylaxis is a rare but serious and potentially fatal complication of anesthesia. Little is known about the incidence and outcome of anaphylaxis in cardiac surgical patients, which we aimed to investigate. Methods: This was a 21-year retrospective study of cardiac surgical patients at Manchester Royal Infirmary, Manchester Foundation Trust, Manchester, UK. Results: A total of 19 cases of anaphylaxis were reported among 17,589 patients (0.108%) undergoing cardiac surgery. The majority (15/19) occurred before cardiopulmonary bypass (CPB), mostly during or within 30 min after the induction of anesthesia (10/19). Two occurred within 15 min of going onto CPB. Of these 17 cases, 11 were abandoned, and 6 proceeded. The severity of reactions in the patients who proceeded ranged from grade II to grade IV of the Ring and Messmer classification. Two cases occurred after the completion of surgery. All patients survived to 90 days. However, this did not appear to be related to CPB or protamine as most of the reactions occurred before CPB. Instead, the most common causative agents were gelofusine, antibiotics, muscle relaxants, and chlorhexidine. In 6 cases, surgery proceeded despite the anaphylaxis, in 11 cases the surgery was postponed, and in 2 cases the procedure had already been completed. Conclusion: As all patients survived, our results provide preliminary support for proceeding with surgery although we cannot speculate on the likely outcomes of patients who were postponed, had their surgery proceeded. Based on our data, the incidence of anaphylaxis in cardiac surgical patients may be 10-20 times higher than in the general surgical population.