Correlation Between End-Tidal Carbon Dioxide and Regional Cerebral Oxygen Saturation During Cardiopulmonary Resuscitation

<b>Background/Objectives:</b> Near-infrared spectroscopy (NIRS) enables the non-invasive assessment of cerebral oximetry, offering insights into the efficacy of oxygen supply to the brain. NIRS, when combined with other monitoring techniques such as capnography, may play a crucial role in advanced patient monitoring during sudden cardiac arrest and post-resuscitation treatment. This research assessed the relationship between end-tidal carbon dioxide (ETCO₂) and regional cerebral oxygen saturation (rSO₂) during cardiopulmonary resuscitation. <b>Methods:</b> The research was performed from 11 January 2023 until 31 January 2024, at the University Hospital in Poland. The cohort of responders included patients who had in-hospital cardiac arrest (IHCA). The Rapid Response Team attached the rSO₂ and ETCO₂ monitoring devices to each patient during cardiopulmonary resuscitation (CPR). The cohort included 104 patients. <b>Results:</b> The correlation coefficient between ETCO₂ and rSO₂ values was 0.641 (95% CI: 0.636-0.646), and during the last 4 min of CPR before ROSC, it was 0.873 (95% CI: 0.824-0.910). <b>Conclusions:</b> The positive correlation between ETCO₂ and rSO₂ may suggest that concurrent monitoring of both parameters during resuscitation might serve as a valuable predictor of CPR efficacy and the likelihood of achieving recovery of spontaneous circulation in a multimodal framework. In the lack of rapid ETCO₂ monitoring capabilities, rSO₂ may function as a simple and effective alternative for assessment.