Background/aim: Some of the patients suffering from cardiac arrest (CA) remain in a chronic unconscious state in intensive care units (ICUs). The primary aim of this study was to evaluate the efficacy of chest compression (CC) on cerebral oxygenation during cardiopulmonary resuscitation (CPR). As a secondary goal, we attempted to determine the effects of regional cerebral oxygen saturation (rSO2) values on consciousness and the survival rate using the Full Outline of Unresponsiveness (FOUR) scoring method.Materials and methods: This observational preliminary study was carried out with 20 patients with CA who were hospitalized in ICUs. The rSO2 values measured by near-infrared spectroscopy were recorded during CA. FOUR scoring was used to determine the neurological status, severity of disease, and degree of organ dysfunction in survivors.Results: Return of spontaneous circulation (ROSC) was gained in 8 (40%) of 20 patients. Maximum rSO2 values were higher in survivors than in nonsurvivors (P = 0.005). The mean FOUR score before CA was 11.50 ± 0.8 in survivors, whereas this value was 7.87 ± 0.7 for 1 week after ROSC (P < 0.0001). There was a significant positive correlation between the minimum and mean rSO2 values and the mean 1-week FOUR scores in survivors (r = 0.811, r = 0.771 and P = 0.015, P = 0.025, respectively).Conclusion: Our results suggest that the maximum rSO2 values affect ROSC while the minimum and mean rSO2 values affect the post-cardiac arrest neurological outcome.