Targeting to 88%–92% did not cause harm.
There is little data on ventilator weaning when it comes to oxygenation goals. Many intensivists adjust the ventilator to maintain an oxygen saturation of at least 95% to buffer against desaturation. However, there are harms caused by hyperoxia especially if the FiO2 remains greater than 60% for long periods of time. There is the concern of creating oxygen free radicals than can affect cardiac function and injure lung parenchyma.
This study randomized 104 ventilated patients into two arms: a conservative strategy arm with a goal peripheral oxygen saturation of 88%–92% and a liberal strategy with a goal peripheral oxygen saturation of >95%. Most of the patients were intubated for a medical reason. Positive end expiratory pressure (PEEP) levels were determined by treating physicians who were not blinded to the intervention. Mean fraction of inspired oxygen (FiO2) at randomization was 0.44.
There was no difference between the groups in terms of organ dysfunction or mortality. Mean saturation in the conservative arm was 93.4% and 97.0% in the liberal arm. Patients in the conservative arm were more likely to have episodes of severe desaturation, but the overall rate of severe desaturation was very low. None of the severe desaturation episodes resulted in permanent injury.
Hopefully, a larger multi-center randomized control trial will be performed to help intensivists understand the optimal oxygen saturation targets for our mechanically ventilated patients.