UK-ROX
Research type
Research Study
Full title
Evaluating the clinical and cost-effectiveness of a conservative approach to oxygen therapy for invasively ventilated adults in intensive care.
IRAS ID
288506
Contact name
Daniel Martin
Contact email
Sponsor organisation
Intensive Care National Audit & Research Centre (ICNARC)
ISRCTN Number
ISRCTN13384956
Duration of Study in the UK
3 years, 3 months, 30 days
Research summary
Research Summary:
Each year, around 184,000 patients are admitted to NHS intensive care units (ICUs) and over 30% require help with their breathing using a ventilator (breathing machine). Giving oxygen through the ventilator is an essential part of this treatment. However, we do not know how much oxygen should be given to patients to optimise their recovery. Both too much, and too little, oxygen may cause harm. The concentration of oxygen given through the ventilator is adjusted according to how much oxygen can be detected in a patient’s blood, known as 'oxygen saturation'. Some studies have shown that in unwell hospitalised patients, having a lower, rather than higher, oxygen saturation may more be beneficial.
We therefore intend to conduct a large clinical trial to find out whether using a lower oxygen target (conservative oxygen therapy) to guide oxygen treatment might lead to better outcomes for patients when compared with the approach currently used in NHS ICUs (usual oxygen therapy). The study will include 16,500 patients from 100 UK NHS ICUs. Patients will be randomly assigned to either the conservative oxygen therapy or usual oxygen therapy group. We will follow all patients up to 90 days later by ‘linking’ study data with routinely collected national records. We will find out if conservative oxygen therapy was more effective than usual oxygen therapy by comparing the number of patients alive in each group at 90 days.
Patient recruitment will start early in 2021 and end in 2023. Results will have a large and immediate impact on ICU clinical practice and on patient outcomes throughout the NHS. Data from the 16,500 patients in this study will also contribute to a larger global study of 40,000 patients. The global study will answer similar questions about oxygen therapy in ICU patients but from an international perspective.
Summary of Results:
Critically ill patients in intensive care units (ICUs) often need extra oxygen while being treated with a breathing machine (mechanical ventilator). Oxygen is an essential treatment, but there is uncertainty about how much oxygen should be given to patients. Too little and too much oxygen may cause harm. Doctors and nurses therefore need evidence to guide safe oxygen treatment for critically ill patients.
The UK-ROX study investigated whether giving less oxygen to critically ill adults on a breathing machine in ICU could improve survival. The study took place in 97 NHS ICUs across England, Wales and Northern Ireland. Between 2021 and 2024, 16,500 adult patients taking part in the study were randomly allocated to one of two groups. One group received a “conservative” oxygen approach, where oxygen levels were adjusted to keep blood oxygen saturation around 90%. The other group received usual oxygen treatment, managed according to normal clinical practice. The researchers then compared outcomes between the two groups. The main outcome was whether patients were alive or had died 90 days after joining the study. The team also examined other outcomes, including length of stay in ICU and hospital, time spent needing specialist organ support, and survival up to one year later.
Patients in the conservative oxygen group received substantially less oxygen overall than those receiving usual care. Despite this reduction in oxygen exposure, there was no difference in survival between the groups. After 90 days, around 35 out of every 100 patients in both groups had died. There were also no differences in other outcomes such as time spent in ICU, time in hospital, or need for organ support.
The findings of the study suggest that routinely targeting lower oxygen levels for all mechanically ventilated adult ICU patients neither improves nor worsens survival compared with current standard care in UK ICUs. This is important because oxygen is one of the most commonly used treatments in ICUs worldwide. The results provide reassurance that current UK practice appears broadly safe and appropriate for most patients. The study was one of the largest ICU trials ever conducted in the UK and included a wide range of patients from across the NHS. Because of its size, the study was able to provide more reliable evidence than many earlier studies.
Overall, the UK-ROX study found that reducing oxygen exposure in critically ill adults on a breathing machine did not reduce deaths or improve recovery. These findings will help guide future practice and research into the safest and most effective use of oxygen therapy on ICUs.
REC name
South Central - Oxford C Research Ethics Committee
REC reference
20/SC/0423
Date of REC Opinion
8 Dec 2020
REC opinion
Favourable Opinion