Non-linear association between arterial oxygen tension and survival after out-of-hospital cardiac arrest: A multicentre observational study

Nicole Mckenzie; Judith Finn; Geoffrey Dobb; Paul Bailey; Glenn Arendts; Antonio Celenza; Daniel Fatovich; Ian Jenkins; Stephen Ball; Janet Bray; Kwok M Ho

doi:10.1016/j.resuscitation.2020.11.021

Non-linear association between arterial oxygen tension and survival after out-of-hospital cardiac arrest: A multicentre observational study

Resuscitation. 2021 Jan:158:130-138. doi: 10.1016/j.resuscitation.2020.11.021. Epub 2020 Nov 21.

Authors

Nicole Mckenzie¹, Judith Finn², Geoffrey Dobb³, Paul Bailey⁴, Glenn Arendts⁵, Antonio Celenza⁶, Daniel Fatovich⁷, Ian Jenkins⁸, Stephen Ball⁴, Janet Bray⁹, Kwok M Ho¹⁰

Affiliations

¹ Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), Curtin University, Bentley, WA, Australia; Intensive Care Unit, Royal Perth Hospital, Perth, WA, Australia. Electronic address: [email protected].
² Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), Curtin University, Bentley, WA, Australia; St John Western Australia, Belmont, WA, Australia; School of Medicine (Emergency Medicine), University of Western Australia, Crawley, WA, Australia; School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
³ Intensive Care Unit, Royal Perth Hospital, Perth, WA, Australia; Faculty of Health and Medical Sciences, University of Western Australia, Crawley, WA, Australia.
⁴ Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), Curtin University, Bentley, WA, Australia; St John Western Australia, Belmont, WA, Australia.
⁵ Faculty of Health and Medical Sciences, University of Western Australia, Crawley, WA, Australia; Fiona Stanley Hospital, Murdoch, WA, Australia.
⁶ School of Medicine (Emergency Medicine), University of Western Australia, Crawley, WA, Australia; Sir Charles Gairdner Hospital, Nedlands, WA, Australia.
⁷ Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), Curtin University, Bentley, WA, Australia; School of Medicine (Emergency Medicine), University of Western Australia, Crawley, WA, Australia; Emergency Medicine, Royal Perth Hospital, Perth, WA, Australia.
⁸ Fremantle Hospital, Fremantle, WA, Australia.
⁹ School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
¹⁰ Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), Curtin University, Bentley, WA, Australia; Intensive Care Unit, Royal Perth Hospital, Perth, WA, Australia; Medical School, University of Western Australia, Crawley, WA, Australia; School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia.

PMID: 33232752
DOI: 10.1016/j.resuscitation.2020.11.021

Abstract

Background: Studies to identify safe oxygenation targets after out-of-hospital cardiac arrest (OHCA) have often assumed a linear relationship between arterial oxygen tension (PaO₂) and survival, or have dichotomised PaO₂ at a supra-physiological level. We hypothesised that abnormalities in mean PaO₂ (both high and low) would be associated with decreased survival after OHCA.

Methods: We conducted a retrospective multicentre cohort study of adult OHCA patients who received mechanical ventilation on admission to the intensive care unit (ICU). The potential non-linear relationship between the mean PaO₂ within the first 24 -hs of ICU admission and survival to hospital discharge (STHD) was assessed by a four-knot restricted cubic spline function with adjustment for potential confounders.

Results: 3764 arterial blood gas results were available for 491 patients in the first 24-hs of ICU admission. The relationship between mean PaO₂ over the first 24-hs and STHD was an inverted U-shape, with highest survival for those with a mean PaO₂ between 100 and 180 mmHg (reference category) compared to a mean PaO₂ of <100 mmHg (adjusted odds ratio [aOR] 0.50 95% confidence interval [CI] 0.30, 0.84), or >180 mmHg (aOR 0.41, 95% CI 0.18, 0.92). Mean PaO₂ within 24 -hs was the third most important predictor and explained 9.1% of the variability in STHD.

Conclusion: The mean PaO₂ within the first 24-hs after admission for OHCA has a non-linear association with the highest STHD seen between 100 and 180 mmHg. Randomised controlled trials are now needed to validate the optimal oxygenation targets in mechanically ventilated OHCA patients.

Keywords: Arterial blood gas analysis; Arterial oxygen tension; Cerebral performance category; Emergency medical services; Neurological outcome; Out-of-hospital cardiac arrest; Post-resuscitation care; Survival.

Publication types

Multicenter Study
Observational Study
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Blood Gas Analysis
Cardiopulmonary Resuscitation*
Cohort Studies
Humans
Out-of-Hospital Cardiac Arrest* / therapy
Oxygen
Retrospective Studies

Substances

Oxygen