Long-term oxygen therapy: in a perfect world.

This issue of RESPIRATORY CARE contains 2 papers of interest that deal with long-term oxygen therapy (LTOT). In the first, Martí et al investigated the efficacy of 2 oxygen-conserving devices in correcting exercise-induced hypoxemia in subjects with either COPD or interstitial lung disease (ILD). Of the 59 subjects who completed the study, 28 were diagnosed with COPD and 31 were diagnosed with ILD. A pulse-demand oxygen delivery system and a pendant reservoir cannula were compared to conventional continuous-flow oxygen therapy. All 3 systems were powered by small compressed oxygen cylinders. In a manner of speaking, the researchers “chased after” a satisfactory SpO2 during exercise in these 2 groups of subjects with lung disease who had first demonstrated exercise-induced hypoxemia. The threshold to qualify for this was an average SpO2 88% during a 6-min walk test (6MWT) without supplemental oxygen. The procedure monitored heart rate, breathing frequency, SpO2, dyspnea (using a modified Borg scale), and distance walked. The researchers found that, despite their best efforts in manipulating the settings of all 3 delivery systems, some 20% of the severe COPD subjects could not achieve a satisfactory SpO2 during exercise (defined as an average SpO2 90%), regardless of the delivery system. In the subjects with ILD the pulsedemand system fell far short of being effective: almost 40% did not achieve a satisfactory SpO2. Interestingly, in both the COPD and the ILD groups the pendant reservoir cannula had the best results in correcting exercise-induced hypoxemia, but the pulse-demand system was the preferred system when given a choice. As the authors noted, the subjects apparently made their choice of device based more on esthetics and comfort than other factors.1