The efficacy of long-term oxygen therapy for hypoxemic COPD patients is well established.
However, oxygen is expensive and the portability of home oxygen is limited by the weight
and bulk of the oxygen source. As a result, there has been a recent surge of interest in
creating oxygen-conserving devices and methods. The efficiency of oxygen therapy can be
improved over steady flow delivery by focusing oxygen delivery to early inspiration. Three
methods for improving oxygen delivery efficiency—transtracheal catheter, reservoir cannula …