Temporal changes in peripheral regional oxygen saturation associated with return of spontaneous circulation after out-of-hospital cardiac arrest: A prospective observational cohort study in Japan

Aim: Temporal changes in cerebral regional oxygen saturation (crSO₂) are useful for predicting return of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA) patients. However, little is known regarding the usefulness of peripheral regional oxygen saturation (prSO₂) associated with OHCA patient outcomes. This study evaluated the association between temporal changes in prSO₂ and ROSC in patients with OHCA.

Methods: This was a prospective study at two tertiary emergency centres in Japan. We evaluated the relationship between ROSC and temporal changes in crSO₂ and prSO₂. The rSO₂ sensor was attached to the patient's forehead and upper arm, and rSO₂ was continuously measured until resuscitative efforts were terminated or until the patient with sustained ROSC (>20 min) arrived at the emergency department.

Results: We included 145 patients with OHCA, of whom 35 achieved ROSC. Witness status (odds ratio [95% confidence interval]: 11.6 [3.13-58.1]) and ΔprSO₂ (1.13 [1.06-1.24]) were significantly associated with ROSC in multiple logistic analysis. In the ROSC group, ΔprSO₂ increased earlier than ΔcrSO₂ during cardiopulmonary resuscitation. In the non-ROSC group, there was no significant difference between ΔcrSO₂ and ΔprSO₂, and neither increased before termination of resuscitation (TOR).

Conclusion: We demonstrated for the first time that prSO₂ is associated with ROSC in OHCA patients and showed that temporal changes in prSO₂ could predict ROSC earlier than those in crSO₂. Our findings could provide time to prepare early interventions after ROSC and assist in determining the TOR for OHCA patients in Japan. Further studies are needed to validate these findings.