Oxygen titration after resuscitation from out-of-hospital cardiac arrest: A multi-centre, randomised controlled pilot study (the EXACT pilot trial)

Janet E. Bray, Cindy Hein, Karen Smith, Michael Stephenson, Hugh Grantham, Judith Finn, Dion Stub, Peter Cameron, Stephen Bernard, on behalf of the EXACT Investigators

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45 Citations (Scopus)


Introduction: Recent studies suggest the administration of 100% oxygen to hyperoxic levels following return-of-spontaneous-circulation (ROSC) post-cardiac arrest may be harmful. However, the feasibility and safety of oxygen titration in the prehospital setting is unknown. We conducted a multi-centre, phase-2 study testing whether prehospital titration of oxygen results in an equivalent number of patients arriving at hospital with oxygen saturations SpO2 ≥ 94%. Methods: We enrolled unconscious adults with: sustained ROSC; initial shockable rhythm; an advanced airway; and an SpO2 ≥ 95%. Initially (Sept 2015–March 2016) patients were randomised 1:1 to either 2 L/minute (L/min) oxygen (titrated) or >10 L/min oxygen (control) via a bag-valve reservoir. However, one site experienced a high number of desaturations (SpO2 < 94%) in the titrated arm and this arm was changed (April 2016) to an initial reduction of oxygen to 4 L/min then, if tolerated, to 2 L/min, and the desaturation limit was decreased to <90%. Results: We randomised 61 patients to titrated (n = 37: 2L/min = 20 and 2–4 L/min = 17) oxygen or control (n = 24). Patients allocated to titrated oxygen were more likely to desaturate compared to controls ((SpO2 < 94%: 43% vs. 4%, p = 0.001; SpO2 < 90%: 19% vs. 4%, p = 0.09). The majority of desaturations (81%) occurred at 2L/min. On arrival at hospital the majority of patients had a SpO2 ≥ 94% (titrated: 90% vs. control: 100%) and all patients had a SpO2 ≥ 90%. One patient (control) re-arrested. Survival to hospital discharge was similar. Conclusion: Oxygen titration post-ROSC is feasible in the prehospital environment, but incremental titration commencing at 4L/min oxygen flow may be needed to maintain an oxygen saturation >90% (NCT02499042).

Original languageEnglish
Pages (from-to)211-215
Number of pages5
Publication statusPublished - Jul 2018


  • Heart arrest
  • Hyperoxia
  • Out-of-hospital cardiac arrest
  • Oxygen
  • Post-resuscitation care

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