Increase in cerebral oxygenation during advanced life support in out-of-hospital patients is associated with return of spontaneous circulation

Introduction: By maintaining sufficient cerebral blood flow and oxygenation, the goal of cardiopulmonary resuscitation (CPR) is to preserve the pre-arrest neurological state. To date, cerebral monitoring abilities during CPR have been limited. Therefore, we investigated the time-course of cerebral oxygen saturation values (rSO(2)) during advanced life support in out-of-hospital cardiac arrest. Our primary aim was to compare rSO(2) values during advanced life support from patients with return of spontaneous circulation (ROSC) to patients who did not achieve ROSC. Methods: We performed an observational study to measure rSO(2) using Equanox T (Nonin, Plymouth, MI) from the start of advanced life support in the pre-hospital setting. Results: rSO(2) of 49 consecutive out-of-hospital cardiac arrest patients were analyzed. The total increase from initial rSO(2) value until two minutes before ROSC or end of advanced life support efforts was significantly larger in the group with ROSC 16% (9 to 36) compared to the patients without ROSC 10% (4 to 15) (P = 0.02). Mean rSO(2) from the start of measurement until two minutes before ROSC or until termination of advanced life support was higher in patients with ROSC than in those without, namely 39% +/- 7 and 31% +/- 4 (P = 0.05) respectively. Conclusions: During pre-hospital advanced life support, higher increases in rSO(2) are observed in patients attaining ROSC, even before ROSC was clinically determined. Our findings suggest that rSO(2) could be used in the future to guide patient tailored treatment during cardiac arrest and could therefore be a surrogate marker of the systemic oxygenation state of the patient.