ANZICS CTG Endorsed Study


The mega randomised registry trial comparing conservative vs. liberal oxygenation targets

Study Description


Provision of life support (mechanical ventilation) is required for most critically ill patients who are admitted to an intensive care unit (ICU). Delivery of supplemental oxygen to ICU patients who require mechanical ventilation often exposes them to a high fraction of inspired oxygen (FIO2) and higher than normal arterial oxygen partial pressure (PaO2).

The ICU-ROX trial findings did not exclude clinically important effects of the oxygen regimens tested on mortality.

This 40,000 participant trial will be conducted in multiple countries and includes innovative trial design features:

  1. Linkage to identify enrolled patients in national ICU registries so that outcome data do not need to be collected specifically for the trial;
  2. Response adaptive randomisation giving trial participants an increased chance of being assigned to the oxygen regimen associated with the lowest mortality risk while the trial is ongoing (based on accumulated data within individual subgroups).


Mega-ROX is a series of multicentre, multinational, randomised, parallel-group, registry-embedded clinical trials nested within an overall 40,000-patient trial sample.


That a conservative approach to oxygen therapy will reduce mortality compared to a liberal approach. However, we anticipate heterogeneity of treatment response and hypothesise that in patients with acute brain pathologies (other than hypoxic brain injuries) and patients with sepsis that liberal oxygen will reduce mortality compared with conservative oxygen.




Paul Young (