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

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. Methods: 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 ETCO 2 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 ETCO 2 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.