Early Hyperoxia in Patients with Traumatic Brain Injury Admitted to Intensive Care in Australia and New Zealand: A Retrospective Multicenter Cohort Study
Early hyperoxia may be an independent risk factor for mortality in critically ill traumatic brain injury (TBI) patients, although current data are inconclusive. Accordingly, we conducted a retrospective cohort study to determine the association between systemic oxygenation and in-hospital mortality, in critically ill mechanically ventilated TBI patients.
Data were extracted from the Australian and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation Adult Patient Database. All adult TBI patients receiving mechanical ventilation in 129 intensive care units between 2000 and 2016 were included in analysis. The following data were extracted: demographics, illness severity scores, physiological and laboratory measurements, institutional characteristics, and vital status at discharge. In-hospital mortality was used as the primary study outcome. The primary exposure variable was the ‘worst’ partial arterial pressure of oxygen (PaO2) recorded during the first 24 h in ICU; hyperoxia was defined as > 299 mmHg. Adjustment for illness severity utilized multivariable logistic regression, the results of which are reported as the odds ratio (OR) 95% CI.
Data concerning 24,148 ventilated TBI patients were extracted. By category of worst PaO2, crude in-hospital mortality ranged from 27.1% (PaO2 40–49 mmHg) to 13.3% (PaO2 140–159 mmHg). When adjusted for patient and institutional characteristics, the only PaO2 category associated with a significantly greater risk of death was < 40 mmHg [OR 1.52, 1.03–2.25]. A total of 3117 (12.9%) patients were hyperoxic during the first 24 h in ICU, with a crude in-hospital mortality rate of 17.8%. No association was evident in between hyperoxia and mortality in adjusted analysis [OR 0.97 (0.86–1.11)].
In this large multicenter cohort of TBI patients, hyperoxia in the first 24 h after ICU admission was not independently associated with greater in-hospital mortality. Hypoxia remains associated with greater in-hospital mortality risk and should be avoided where possible.
KeywordsTraumatic brain injury Oxygen exposure Mortality
The authors wish to acknowledge the participation of the contributing hospitals: Albury Base Hospital ICU, Alfred Hospital ICU, Alice Springs Hospital ICU, Allamanda Private Hospital ICU, Armadale Health Service ICU, Armidale Rural Referral Hospital ICU, Auckland City Hospital DCCM, Austin Hospital ICU, Ballarat Health Services ICU, Bankstown-Lidcombe Hospital ICU, Bathurst Base Hospital ICU, Bendigo Health Care Group ICU, Box Hill Hospital ICU, Bunbury Regional Hospital ICU, Bundaberg Base Hospital ICU, Caboolture Hospital HDU, Cairns Hospital ICU, Calvary Hospital (Canberra) ICU, Calvary Hospital (Lenah Valley) ICU, Calvary Mater Newcastle ICU, Campbelltown Hospital ICU, Canberra Hospital ICU, Central Gippsland Health Service ICU, Christchurch Hospital ICU, Coffs Harbour Health Campus ICU, Concord Hospital (Sydney) ICU, Dandenong Hospital ICU, Dubbo Base Hospital ICU, Dunedin Hospital ICU, Epworth Freemasons Hospital ICU, Fiona Stanley Hospital ICU, Flinders Medical Centre ICU, Footscray Hospital ICU, Frankston Hospital ICU, Fremantle Hospital ICU, Gold Coast University Hospital ICU, Gosford Hospital ICU, Goulburn Valley Health ICU, Grafton Base Hospital ICU, Greenslopes Private Hospital ICU, Griffith Base Hospital ICU, Hawkes Bay Hospital ICU, Hervey Bay Hospital ICU, Holy Spirit Northside Hospital ICU, Hornsby Ku-ring-gai Hospital ICU, Ipswich Hospital ICU, John Flynn Private Hospital ICU, John Hunter Hospital ICU, Joondalup Health Campus ICU, Knox Private Hospital ICU, Latrobe Regional Hospital ICU, Launceston General Hospital ICU, Lismore Base Hospital ICU, Liverpool Hospital ICU, Logan Hospital ICU, Lyell McEwin Hospital ICU, Mackay Base Hospital ICU, Macquarie University Private Hospital ICU, Manly Hospital & Community Health ICU, Manning Rural Referral Hospital ICU, Maroondah Hospital ICU, Mater Adults Hospital (Brisbane) ICU, Mater Private Hospital (Brisbane) ICU, Mater Private Hospital (Sydney) ICU, Mersey Community Hospital ICU, Middlemore Hospital ICU, Mildura Base Hospital ICU, Monash Medical Centre-Clayton Campus ICU, Mount Isa Hospital ICU, Nambour General Hospital ICU, Nelson Hospital ICU, Nepean Hospital ICU, North Shore Hospital ICU, North West Regional Hospital (Burnie) ICU, Northeast Health Wangaratta ICU, Orange Base Hospital ICU, Port Macquarie Base Hospital ICU, Prince of Wales Hospital (Sydney) ICU, Prince of Wales Private Hospital (Sydney) ICU, Princess Alexandra Hospital ICU, Queen Elizabeth II Jubilee Hospital ICU, Redcliffe Hospital ICU, Robina Hospital ICU, Rockhampton Hospital ICU, Rockingham General Hospital ICU, Rotorua Hospital ICU, Royal Adelaide Hospital ICU, Royal Brisbane and Women’s Hospital ICU, Royal Darwin Hospital ICU, Royal Hobart Hospital ICU, Royal Melbourne Hospital ICU, Royal North Shore Hospital ICU, Royal Perth Hospital ICU, Royal Prince Alfred Hospital ICU, Shoalhaven Hospital ICU, Sir Charles Gairdner Hospital ICU, South West Healthcare (Warrnambool) ICU, St Andrew’s War Memorial Hospital ICU, St George Hospital (Sydney) ICU, St George Hospital (Sydney) ICU2, St George Private Hospital (Sydney) ICU, St Vincent’s Hospital (Melbourne) ICU, St Vincent’s Hospital (Sydney) ICU, St Vincent’s Hospital (Toowoomba) ICU, St Vincent’s Private Hospital (Sydney) ICU, Sunshine Hospital ICU, Sutherland Hospital & Community Health Services ICU, Sydney Adventist Hospital ICU, Tamworth Base Hospital ICU, Taranaki Health ICU, Tauranga Hospital ICU, The Northern Hospital ICU, The Prince Charles Hospital ICU, The Queen Elizabeth (Adelaide) ICU, The Townsville Hospital ICU, The Wesley Hospital ICU, Timaru Hospital ICU, Toowoomba Hospital ICU, Tweed Heads District Hospital ICU, University Hospital Geelong ICU, Wagga Wagga Base Hospital & District Health ICU, Waikato Hospital ICU, Wellington Hospital ICU, Western District Health Service (Hamilton) ICU, Westmead Hospital ICU, Westmead Private Hospital ICU, Whangarei Area Hospital, Northland Health Ltd ICU, Wimmera Health Care Group (Horsham) ICU, Wollongong Hospital ICU, Wyong Hospital ICU.
DO, DP, AU, and CN designed the study. DP/AU had full access to the raw data and take responsibility for the integrity of the data and the accuracy of the data analysis. Statistical analysis was performed by DP. DO/AU drafted the initial manuscript. All authors critically revised the manuscript for important intellectual content and read and approved the final version.
Source of Support
Professor Andrew Udy gratefully acknowledges salary support from the National Health and Medical Research Council of Australia (Early Career Fellowship; GNT1124532). ANZICS CORE is funded by the State and Territory Health Departments of Australia and the New Zealand Ministry of Health to monitor performance and provide benchmarking services to ICUs and Health Departments throughout both countries.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
Ethics approval was obtained from the Alfred Hospital Human Research Ethics Committee (HREC reference number 162/17), with a waiver of individual patient informed consent.
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