Can end-tidal CO2 measurement replace arterial partial CO2 in emergency department respiratory distress management?

Objective: To assess the feasibility of using end-tidal carbon dioxide (EtCO2) as a non-invasive substitute for partial pressure of arterial carbon dioxide (PaCO2) in emergency department (ED) triage and follow-up, and to explore the potential of partial pressure of venous carbon dioxide (PvCO(2)) as an alternative to PaCO2. Design: Prospective cross-sectional study. Setting: Tertiary university hospital. Patients or participants: 97 patients presenting with acute respiratory distress to the ED. Interventions: EtCO2, arterial blood gases, and venous blood gases measured at admission (0 min), 60 min, and 120 min. Main variables of interest: CO2 levels. Results: Among 97 patients (mean age: 70.93 +/- 9.6 years; 60.8% male), EtCO2 > 45 mmHg at admission showed strong positive correlations with PaCO2 and PvCO(2) (r = 0.844, r = 0.803; p < 0.001, respectively). Significant positive correlation was observed between 60-min EtCO2 and PaCO2 (r = 0.729; p < 0.001). Strong correlation between PaCO2 and PvCO(2) at 120 min when EtCO2 > 45 mmHg (r = 0.870; p < 0.001). EtCO2 was higher in hospitalized patients compared to discharged ones. Conclusions: EtCO2 appears promising as a substitute for PaCO2 in ED patients with acute respiratory distress within the initial two hours of treatment. Venous blood gas sampling offers a less invasive alternative to arterial sampling, facilitating simultaneous blood tests. (c) 2024 Elsevier Espana, S.L.U. and SEMICYUC. All rights are reserved, including those for text and data mining, AI training, and similar technologies.