Question special

In the study mentioned in your introduction about the step wise conservative oxygenation targets, they found no improvement in ICU mortality, but did find improvement in hospital mortality. I was thinking of possible reasons for this finding compared to your study. One thought was they had a higher target PaO2 (55 to 86 compared to 55 to 70, and their mean was 76), or if it was related to their step wise approach to lowering PaO2. What are your thoughts on this? Thank you!