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Low end-tidal CO2 as a real-time severity marker of intra-anaesthetic acute hypersensitivity reactions.

Abstract : Background: Prompt diagnosis of intra-anaesthetic acute hypersensitivity reactions (AHR) is challenging because of the possible absence and/or difficulty in detecting the usual clinical signs and because of the higher prevalence of alternative diagnoses. Delayed epinephrine administration during AHR, because of incorrect/delayed diagnosis, can be associated with poor prognosis. Low end-tidal CO2 (etCO2) is known to be linked to low cardiac output. Yet, its clinical utility during suspected intra-anaesthetic AHR is not well documented. Methods: Clinical data from the 86 patients of the Neutrophil Activation in Systemic Anaphylaxis (NASA) multicentre study were analysed. Consenting patients with clinical signs consistent with intra-anaesthetic AHR to a neuromuscular blocking agent were included. Severe AHR was defined as a Grade 3-4 of the Ring and Messmer classification. Causes of AHR were explored following recommended guidelines. Results: Among the 86 patients, 50% had severe AHR and 69% had a confirmed/suspected IgE-mediated event. Occurrence and minimum values of arterial hypotension, hypocapnia and hypoxaemia increased significantly with the severity of AHR. Low etCO2 was the only factor able to distinguish mild [median 3.5 (3.2;3.9) kPa] from severe AHR [median 2.4 (1.6;3.0) kPa], without overlap in inter-quartile range values, with an area under the receiver operator characteristic curve of 0.92 [95% confidence interval: 0.79-1.00]. Among the 41% of patients who received epinephrine, only half received it as first-line therapy despite international guidelines. Conclusions: An etCO2 value below 2.6 kPa (20 mm Hg) could be useful for prompt diagnosis of severe intra-anaesthetic AHR, and could facilitate early treatment with titrated doses of epinephrine.
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Submitted on : Tuesday, March 17, 2020 - 2:30:41 PM
Last modification on : Monday, June 21, 2021 - 1:40:03 PM

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Aurélie Gouel-Chéron, L. de Chaisemartin, Friederike Jönsson, P. Nicaise-Roland, V. Granger, et al.. Low end-tidal CO2 as a real-time severity marker of intra-anaesthetic acute hypersensitivity reactions.. British Journal of Anaesthesia, Oxford University Press (OUP), 2017, 119 (5), pp.908-917. ⟨10.1093/bja/aex260⟩. ⟨pasteur-02510059⟩



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