Perioperative anaphylaxis and investigations: a local study in Hong Kong.

INTRODUCTION: Data on local intraoperative anaphylaxis in Hong Kong is scarce, with few reviews available. We aimed to study the characteristics, presentations and workup results of cases referred to a local allergy clinic.
METHODS: A retrospective review was performed of patient referrals and workup results for suspected intraoperative anaphylaxis at Queen Mary Hospital drug allergy clinic in 2012-2016.
RESULTS: Tryptase was checked in only 81.7% (49/60) of the cases, most of which showed elevation (71.4%, 35/49). Among the 59 patients who received a workup, 47 (79.7%) showed positive findings, with a particularly high yield in the tryptase-positive subgroup (88.6%, 31/35). Among the 54 patients who consented to skin tests (the most sensitive investigation), 43 (79.6%) cases were positive. Overall, neuromuscular blockers were the commonest cause (25.0%, 15/60) of intraoperative anaphylaxis, while antibiotics ranked second (23.3%, 14/60). The timing of reactions was an important indication of potential allergens. For example, the majority of the neuromuscular blocker allergies occurred during the induction phase, while all gelofusine allergic events were in the maintenance phase of anaesthesia. 13 (21.7%) out of 60 cases received subsequent general anaesthesia procedures, with no recurrence of allergic reactions.
CONCLUSION: Proper workup after an intraoperative anaphylactic event has a fairly good chance of identifying the causative allergen. These results are useful for patient management and the planning of subsequent anaesthetic procedures. Copyright: © Singapore Medical Association.