Evaluation of a Portable Blood Gas Analyzer for Prehospital Triage in Carbon Monoxide Poisoning: Instrument Validation Study

Article Article scientifique Article Evaluation of a Portable Blood Gas Analyzer for Prehospital Triage in Carbon Monoxide Poisoning: Instrument Validation Study eng 2023-10-06 2023-10-06 author Lyon Matthieu 0000-0002-6507-0865 773679 author Fehlmann Christophe A 0000-0002-4163-0338 633754 Département d'anesthésiologie, pharmacologie et soins intensifs (APSIC) Christophe Fehlmann author Augsburger Marc 0000-0002-5606-3831 677425 author Schaller Thomas 0000-0002-5502-0055 author Zimmermann Catherine 0000-0001-8631-6812 82504 author Celi Julien 0000-0002-8534-8908 557397 author Gartner Birgit Andrea 0000-0003-0726-3201 89644 Birgit Gartner author Lorenzon Nicolas 0009-0007-6356-9818 656071 author Sarasin François 0000-0002-1169-8526 65003 Décanat et administration de la faculté de médecine (ADMED) author Suppan Laurent 0000-0001-6989-6421 505697 Département d'anesthésiologie, pharmacologie et soins intensifs (APSIC) e48057 10.2196/48057 37801355 2561-326X PMC10589834 https://formative.jmir.org/2023/1/e48057 Background: Carbon monoxide (CO) poisoning is an important cause of morbidity and mortality worldwide. Symptoms are mostly aspecific, making it hard to identify, and its diagnosis is usually made through blood gas analysis. However, the bulkiness of gas analyzers prevents them from being used at the scene of the incident, thereby leading to the unnecessary transport and admission of many patients. While multiple-wavelength pulse oximeters have been developed to discriminate carboxyhemoglobin (COHb) from oxyhemoglobin, their reliability is debatable, particularly in the hostile prehospital environment. Objective: The main objective of this pilot study was to assess whether the Avoximeter 4000, a transportable blood gas analyzer, could be considered for prehospital triage. Methods: This was a monocentric, prospective, pilot evaluation study. Blood samples were analyzed sequentially with 2 devices: the Avoximeter 4000 (experimental), which performs direct measurements on blood samples of about 50 µL by analyzing light absorption at 5 different wavelengths; and the ABL827 FLEX (control), which measures COHb levels through an optical system composed of a 128-wavelength spectrophotometer. The blood samples belonged to 2 different cohorts: the first (clinical cohort) was obtained in an emergency department and consisted of 68 samples drawn from patients admitted for reasons other than CO poisoning. These samples were used to determine whether the Avoximeter 4000 could properly exclude the diagnosis. The second (forensic) cohort was derived from the regional forensic center, which provided 12 samples from documented CO poisoning. Results: The mean COHb level in the clinical cohort was 1.7% (SD 1.8%; median 1.2%, IQR 0.7%-1.9%) with the ABL827 FLEX versus 3.5% (SD 2.3%; median 3.1%, IQR 2.2%-4.1%) with the Avoximeter 4000. Therefore, the Avoximeter 4000 overestimated COHb levels by a mean difference of 1.8% (95% CI 1.5%-2.1%). The consistency of COHb readings by the Avoximeter 4000 was excellent, with an intraclass correlation coefficient of 0.97 (95% CI 0.93-0.99) when the same blood sample was analyzed repeatedly. Using prespecified cutoffs (5% in nonsmokers and 10% in smokers), 3 patients (4%) had high COHb levels according to the Avoximeter 4000, while their values were within the normal range according to the ABL827 FLEX. Therefore, the specificity of the Avoximeter 4000 in this cohort was 95.6% (95% CI 87%-98.6%), and the overtriage rate would have been 4.4% (95% CI 1.4%-13%). Regarding the forensic samples, 10 of 12 (83%) samples were positive with both devices, while the 2 remaining samples were negative with both devices. Conclusions: The limited difference in COHb level measurements between the Avoximeter 4000 and the control device, which erred on the side of safety, and the relatively low overtriage rate warrant further exploration of this device as a prehospital triage tool. Avoximeter 4000 CO-oximetry Blood gas Blood work Carbon monoxide Carbon monoxide intoxication Carbon monoxide poisoning Cohort study Medical device Oximeter Pilot study Poisoning Prehospital triage Pulse oximeter Sensor Triage Triage tool Dewey 616 Dewey 617 Dewey 614.1 63 Département d'anesthésiologie, pharmacologie, soins intensifs et urgences 229 67 Institut de médecine légale 22A2 56 Département de médecine 221 false 17 Médecine d'urgence 24 JMIR formative research 7 1ca20837-0adf-48cc-88d2-adfd45c71d75 Article (Published version) Public 10.2196-48057.pdf 282264 application/pdf CC BY-4.0 5aabec34d2ad2c1e974b05920b3c04afdc22877213e806ac36a1df3e4f136b2c openAccess Faculté de médecine / Section de médecine clinique / Département d'anesthésiologie, pharmacologie, soins intensifs et urgences Faculté de médecine / Section de médecine clinique / Département de santé et médecine communautaires / Institut de médecine légale Faculté de médecine / Section de médecine clinique / Département de médecine

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Evaluation of a Portable Blood Gas Analyzer for Prehospital Triage in Carbon Monoxide Poisoning: Instrument Validation Study	JMIR formative research			2023	188	163

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Lorenzon, Nicolas