A New Vital Sign in Determining the Triage Category in Emergency Department Presentations: End-Tidal Carbon Dioxide

Abstract

Objective: To investigate whether patients’ end-tidal carbon dioxide (ETCO2) values ​​measured at the time of their presentation to the emergency department can be used together with vital signs in determining their triage categories and predicting hospitalization. Material and method: This prospective, observational, cross-sectional study was conducted between May 1, 2023, and June 1, 2023, at the emergency department of a tertiary hospital. The study included patients aged >18 years who presented to the emergency department and were evaluated to have a triage category of level 2, 3, or 4 according to the five-step triage system. The patients’ vital signs were measured at the time of their presentation to the emergency department and the ETCO2 values ​​measured through a nasal cannula were statistically evaluated in terms of their relationship with triage categories and hospitalization indications. Results: A total of 1,100 patients were included in the study. According to the triage category of the patients, the mean ETCO2 values for triage levels 2, 3, and 4 were 27.1±3.6, 30.6±3.1, and 35.4±3.5, respectively, indicating statistically significant differences (p<0.001). When the relationship of ETCO2 and vital signs with hospitalization indications evaluated at the emergency department was examined, the area under the receiver operating characteristic curve for ​​ ETCO2 was 0.733, which was statistically significant (p<0.001). Conclusion: On completion of the study, it was concluded that the ETCO2 values ​​measured at the time of presentation to the emergency department can be a new vital sign that can be used to determine the triage categories of patients and identify those who require hospitalization.