Gouel-Cheron A, et al. - This study sheds light on the clinical utility of low end-tidal CO₂ (etCO₂) during suspected intra-anaesthetic acute hypersensitivity reactions (AHR). Findings demonstrated that for prompt diagnosis of severe intra-anaesthetic AHR and, for facilitating early treatment with titrated doses of epinephrine, an etCO₂ value below 2.6 kPa (20 mm Hg) could be useful.