Oxygen therapy boosts exercise performance in patients with cyanotic CHD

Supplemental oxygen helps patients with cyanotic congenital heart disease (CHD) improve their exercise performance, particularly in terms of endurance time and maximal work rate, a new trial has found.

Seven patients (median age 36 years, four women) participated in the present randomized, sham-controlled, crossover trial. Participants were subjected to four cardiopulmonary exercise tests to exhaustion while breathing either oxygen-enriched or ambient air.

Primary outcomes included maximal exercise capacity and duration. Parameters such as changes in symptoms, oxygen saturation, heart rate, and tidal volume (VT) were set as secondary endpoints.

Under an incremental exercise protocol, the maximal exercise capacity was 83 W under oxygen-enriched air, as opposed to only 76 W in ambient air. The resulting mean difference of 9 W was statistically significant in favour of the oxygen-enriched condition (p=0.046).

Similarly, under a constant work-rate exercise protocol, oxygen-enriched air led to significant improvements in endurance. The median exercise duration was 468 s in the oxygen condition, as opposed to only 412 s when tasks were performed in ambient air. The resulting difference of 56 s was statistically significant (p=0.018).

“The results of our pilot study encourage further exploration of the impact of supplemental oxygen therapy during exercise training or daily activity in cyanotic CHD in longer-term, sufficiently powered studies,” the researchers said.

Such future efforts would “unravel the question of whether oxygen therapy applied during everyday activities and training would result in persistently improved exercise performance and potentially quality of life in this subgroup of CHD patients with the most severe exercise limitations,” they added.