• COPD

Recognition that there are risks associated with hyperoxaemia, as well as hypoxaemia, with the use of oxygen therapy in critically ill patients, has led to a paradigm shift in clinical practice, from the traditional approach of liberal administration to titration within a target oxygen saturation range.1 This paradigm shift, colloquially referred to as ‘swimming between the flags’,2 particularly applies to the use of oxygen in severe exacerbations of chronic obstructive pulmonary disease (COPD), in which guidelines now recommend that oxygen is titrated to a target oxygen saturation range of 88%–92%.2–4 This recommendation is based on the landmark randomised controlled trial in patients with acute exacerbations of COPD, in which oxygen therapy titrated to maintain oxygen saturations between 88% and 92% in the prehospital setting reduced the risk of mortality by 58%, when compared with high concentration oxygen therapy.5

While this randomised controlled trial provides the evidence base for the recommended 88%–92% target range, it raises the important question as to whether a ‘physiologically normal’ target of 93%–96%, that also avoids hyperoxaemia, may result in better outcomes than the 88%–92% target. A 93%–96% range is attractive, as it would achieve a modest increase in the arterial partial …