Automated O 2 titration improves exercise capacity in patients with hypercapnic chronic obstructive pulmonary disease: a randomised controlled cross-over trial.

Automatically titrated O-2 flows (FreeO(2)) was compared with constant O-2 flow on exercise capacity, O-2 saturation and risk of hyperoxia-related hypercapnia in patients with severe COPD with baseline hypercapnia and long-term oxygen therapy (LTOT). Twelve patients were enrolled in a randomised double-blind cross-over study to perform exercise with either FreeO(2) or constant flow. Endurance time (primary outcome) and SpO(2) were both significantly improved with FreeO(2) compared with constant flow (p<0.04), although pCO(2) was similar in both conditions. Automated titration of O-2 significantly and clinically improved endurance walking time in patients with severe COPD receiving LTOT, without worsening of pCO(2).