Exploring the clinical significance of capnometry setting

Abstract

Background: Traditional vital signs are quick and noninvasive values critical in the risk stratification of patients arriving at an emergency department. However, recent research has suggested that our current vital signs alone may be insufÏcient for initial patient assessment. Therefore, emergency physicians need to investigate whether the use of capnography in severe patients can predict treatment complications and mortality. Materials and Methods: This prospective study enrolled adult patients in the emergency department of Mongolia-Japan Hospital from June 2023 to December 2023. Patients had standard vital signs measured along with exhaled ETCO2 at triage. Outcome measures included in-hospital mortality and ICU admission. Results: A total of 233 cases in the study were divided into two groups: survivors (91.6%) and nonsurvivors (8.4%). The nonsurvivors had higher rates of respiratory disease (36.6%, p-0.002) and sepsis (50%, p<0.001). There were significant differences in parameters such as EtCO2 (p<0.001), respiratory rate (p<0.001), and SpO2 (p<0.001) in two groups. The area under the curve (AUC) for predicting in-hospital mortality for EtCO2 was 0.886 (cut-off value 18.5, p<0.001). There were 50 (21.5%) patients admitted to the intensive care unit (ICU), and the EtCO2 AUC for predicting ICU admission was 0.826 (cut-off value 19.5, p<0.001). Correlations between expired EtCO2 and serum lactate, anion gap, and HCO3 were rho = −0.357 (p<0.001), rho = −0.212 (p=0.099), rho = −0.681 (p<0.001), respectively. Conclusions: 1. EtCO2 was found to be the most sensitive predictor of in-hospital mortality among amino parameters measured at the time of classification. Incorporating EtCO2 into the primary triage assessment may be a cost-effective method to aid in the timely determination of disease severity and have an important impact on clinical decision-making. 2. The amount of carbon dioxide at the end of exhalation is directly related to indicators of metabolic acidification.