D2.274 - Incidence of Perioperative Hypersensitivity Reactions in Spanish hospitals group. Three years of study 2022 to 2024

Perioperative hypersensitivity reactions (POH) are rare but life-threatening, with an incidence ranging from 1:353 to 1:18,600 anaesthetic procedures (AP). This variability arises from differences in anaesthetic practices, study methodologies, and the ratio of reported POH to the total number of occurrences. In 2022, a research project (PI21/00969) involving 13 Spanish hospitals began to investigate POH. Our goal is to describe the incidence of POH reactions in our group.

All 13 participating hospitals followed a common study protocol and had at least one referral anaesthesiologist and allergist. We systematically identified and evaluated all suspected POH during anaesthesia from 2022 to 2024 and all AP from each location.

After obtaining the patient's informed consent, all cases were evaluated by the allergologist/anaesthesiologist team. Skin tests (skin prick and intradermal tests), specific IgE, acute and basal serum tryptase measurement, and drug provocation were performed following EACCI POH recommendations. EAACI POH severity classification was used. Incidence rates were calculated for each centre and the entire group.

Over three years, 330 patients were referred for investigation (2022: 108, 2023: 103, and 2024: 119). The mean age was 52.34 (SD 17.89) years, with 183 (55.45%) being female. Atopy was present in 90 (27.27%) cases. Reactions occurred during: Pre-anaesthesia: 89 cases (26.97%), Surgery: 163 cases (49.39%), Emergence: 70 cases (21.21%), Recovery: 7 cases (2.42%). The severity of the reaction was grade I in 180 (54.5%) cases, grade II in 58 (17.6%) cases, grade III in 85 (25.8%) cases and grade IV in 7 (2.1%) cases We obtained tryptase samples from 183 patients, and it was elevated in 52 (28%).

In this period, 989184 (355743 in 2022, 330437 in 2023 and 303004 in 2024) AP were performed.

The overall incidence was 1 in 2997.53 (989184/330) anaesthetic procedures, with a median of 1 in 3208.13 procedures (min: 1 in 1018.4; max: 1 in 15089.5).

The annual incidence increases from 1 in 3293.91 in 2022 to 1 in 2546.25 AP in 2024.

Our group has improved POH incident communication by developing collaboration strategies between allergologists and anaesthesiologists, providing incident communication tools (referral form, anaphylaxis kit), and implementing medical education.