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

Abstract

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). F_IO₂ 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).

Keywords: Hyperoxia; Out-of-hospital cardiac arrest; Oxygen reserve index; Oxygen saturation; Post-resuscitation care; Pre-hospital oxygen titration.