Relationship Between Delta CO₂ and Mortality in Cardiac Arrest Patients

<b>Introduction: </b>Cardiac arrest is a sudden and unexpected condition that occurs for various reasons. Early identification and resuscitation efforts are crucial for both restoring spontaneous circulation and ensuring neurological survival. This study investigated the relationship between arterial partial pressure of carbon dioxide (PaCO₂) and end-tidal carbon dioxide (ETCO₂) difference stated as the Delta CO₂ and the return of spontaneous circulation (ROSC) in cardiac arrest patients.<br /> <b>Methods: </b>The study was conducted prospectively on patients who had experienced cardiac arrest and were subsequently followed up in the emergency clinic of a tertiary education and research hospital or transported by ambulance. The resuscitation efforts times, outcomes, demographic data, chronic diseases, ETCO2, and PaCO2 levels of the patients were monitored and the collected data were subjected to analysis. The patients who achieved ROSC were classified as No ROSC group1, the patients who did not achieve ROSC were classified as No ROSC group2, and the two groups were subsequently analyzed.<br /> <b>Results: </b>The study cohort comprised 57 patients who had been admitted to the emergency department. Among the arrest patients, 25 (43.9%) achieved ROSC, while 32 (56.1%) did not. A comparison was conducted between the PaCO₂ and ETCO₂ values of the patients, revealing a significantly higher mean PaCO₂ at the 20th minute in No ROSC group2 compared to ROSC group(p=0.000). Mean PaCO₂ values at 0 and 10 minutes were significantly higher in ROSC group(ROSC) compared to No ROSC group2 (p=0.036). Conversely, mean ETCO₂ values at 0 and 10 minutes were significantly higher in ROSC group(p=0.006 and 0.027, respectively). The deltaCO2 value of the patients was significantly higher in No ROSC group2 compared to ROSC groupat the 0th, 10th, and 20th minutes (0.019, 0.028, and 0.007, respectively).<br /> <b> Conclusion:</b> Our findings suggest that, ETCO₂ levels during CPR and a smaller Delta CO₂ may predict a higher likelihood of ROSC.