Postresuscitation oxygen reserve index-guided oxygen titration in out-of-hospital cardiac arrest survivors: A randomised controlled trial

Background and purpose Hyperoxia after return of spontaneous circulation is potentially harmful, and oxygen titration in a prehospital setting is challenging. This study aimed to compare outcomes of oxygen reserve index-supported prehospital oxygen titration during prehospital transport with those of standard oxygen titration. Methods and trial design We enrolled patients who experienced return of spontaneous circulation after cardiac arrest in a prospective randomized study. Patients were randomly divided (1:1) to undergo oxygen titration based on the oxygen reserve index and SpO2 (intervention) or SpO2 only (control). FIO2 titration targeted SpO2 level maintenance at 94–98%. The primary outcome was the normoxia index, reflecting the proportion of both hyperoxia- and hypoxia-free time during prehospital intervention. Results A total of 92 patients were included in the study. The mean normoxia index was 0.828 in the control group and 0.847 in the intervention group (difference=0.019 [95% CI, -0.056–0.095]), with no significant difference between the groups. No significant differences were found in the incidence of hypoxia or hyperoxia between groups. No difference was found in the mean PaO2 at hospital admission (116 mmHg [IQR: 89–168 mmHg] in the control group vs 115 mmHg [IQR: 89–195 mmHg] in the intervention group; p=0.86). No difference was observed in serum neuron-specific enolase levels 48 h post-ROSC after adjustment for known confounders. Conclusion Oxygen reserve index- combined with pulse oximetry-based prehospital oxygen titration did not significantly improve the normoxia index compared with standard oxygen titration based on pulse oximetry alone (NCT03653325).