Intensive care unit randomised trial comparing two approaches to oxygen therapy (UK-ROX)

INTERVENTION: Patients will be randomly allocated ("randomized"), in a 1:1 ratio, to one of two treatment groups: conservative oxygen therapy (intervention) or usual oxygen therapy (control). Each participant will have a 50/50 chance of being enrolled in the intervention or control group. Patients receiving supplemental oxygen during invasive mechanical ventilation in ICUs will eligible for the trial. The trial interventions are intended to be delivered early in the course of mechanical ventilation, just as would be the case in standard NHS practice, and therefore patients must be randomised within 12 hours of meeting the eligibility criteria. If a patient is randomized to the usual oxygen therapy (control) group, the clinical team will continue to deliver oxygen therapy as per local practice and clinical management will not be influenced by the trial. The intervention should be continued until discharge from ICU, or 90 days after randomisation, whichever is sooner. If a participant is readmitted to ICU within the 90 days, the intervention should be recommenced. If a patient is randomized to conservative oxygen therapy (intervention) group, the clinical team will use an SpO2 target range of 90‐93%. the lowest concentration of oxygen possible should be administered to maintain the patient’s SpO2 at or just above 90%. For patients receiving oxygen, SpO2 should not rise above 93%. Alarms should be set to sound at an SpO2 of 89% and below and 94% and above. The intervention remains the same once a patient is extubated, regardless of the modality by which they receive oxygen therapy. The intervention should be continued until discharge from ICU, or 90 days after randomisation, whichever is sooner. If a participant is readm CONDITION: Invasive ventilation in intensive care ; Not Applicable PRIMARY OUTCOME: ; Primary clinical outcome:; 90‐day all‐cause mortality, assessed through review of patient medical notes at 90 days post‐randomisation and/or data linkage with nationally held death registrations; ; Primary economic outcome:; Incremental costs, QALYs and net monetary benefit at 90 days, assessed by combining Health‐related Quality of Life (EuroQol EQ‐5D‐5L questionnaire) data with valued resource use data obtained via a health services questionnaire and data obtained through linkage with national hospital episode statistics, death registrations and the national clinical audit for adult critical care.; INCLUSION CRITERIA: 1. Aged =18 years 2. Receiving invasive mechanical ventilation in the ICU following an unplanned ICU admission (i.e. not admitted after an elective procedure) OR invasive mechanical ventilation started in the ICU (i.e. the patient was intubated in the ICU) 3. Receiving supplemental oxygen (fractional inspired concentration of oxygen (FiO2) >0.21) at the time of enrolment SECONDARY OUTCOME: ; 1. ICU and hospital mortality (censored at 90 days), assessed through review of patient medical notes at the relevant timepoints and/or data linkage with nationally held death registrations; 2. Mortality at 60 days and 1 year, assessed through review of patient medical notes at the relevant timepoints and/or data linkage with nationally held death registrations; 3. Duration of ICU and acute hospital stay (censored at 90 days), assessed through data linkage with the national clinical audit for adult critical care; 4. Health‐related quality of life at 90 days, assessed using the EuroQol EQ‐5D‐5L questionnaire administered to patients at 90 days; 5. Resource use and costs at 90 days, assessed by valuing resource use data obtained via a health services questionnaire administered to patients at 90 days and data linkage with national hospital episode statistics and the national clinical audit for adult critical care; 6. Estimated lifetime incremental cost‐effectiveness, estimated by combining 90‐day HrQoL data with valued resource use data obtained via a health services questionnaire at 90 days, data obtained through linkage with national hospital episode statistics, death registrations and the national clinical audit for adult critical care;