Causes Of Perioperative Allergic Reactions – Our Experience In The Last Two Years

Allergic reactions during general anaesthesia (GA) are frequent and usually due to one of several drugs. The study of these patients is essential to prevent future reactions, but not all patients are referred to the Allergy Clinic to clarify the reaction. Retrospective report of all patients referred to our Centre through a specific pathway, from September 2011 to August 2013. Skin prick, intradermal and drug provocation tests undertaken as appropriate. 18 patients investigated; mean age 58.05 + 9.60 years. Surgeries varied (6 orthopedic, 2 laparotomies, 2 cardiac, 2 laparoscopies, 1 cystoscopy, 1 septoplasty, 1 fat graft, 1 angiogram, 1 thoracotomy, 1 ERCP). Most patients received NMBAs, propofol, fentanyl and midazolam; chlorhexidine was used in 13 patients, povidone iodine in 6; and latex in 14. Additionally, some received antibiotics (9), local anaesthetics (4), etomidate (3), contrast media (2), ondansetron (1) and diclofenac (1). Reactions comprised anaphylaxis (7), urticaria (5), hypotension (2), facial angioedema (3) and dyspnoea (1). Mast cell tryptase was raised in 4 patients (mean 40.4μg/l), normal in 1, not measured in 13. Specific IgE to drugs were negative in all but 1 patient, positive to suxamethonium (1.2kua/l). Allergy was confirmed in 9 patients, dermographism impeded study in 2, pharmacological cause was observed in 1 and cause was not identified in 6. Causes were NMBAs in 5 patients and midazolam in 3, chlorhexidine (2), povidone iodine (1), and ondansetron (1). GA allergy investigation allowed identification of a cause in most patients, enabling them to have further anaesthesia with safe alternatives.