Till Örebro universitet

Background: The oxygen need increases with activity in patients with COPD and long-term oxygen treatment (LTOT). Thus, the usual fixed dose given at rest may be insufficient to maintain the oxygen saturation (SpO2), which may influence the patient’s performance. The aim of this study was to evaluate the effect of automated oxygen titration (AOT) compared to usual fixed-dose oxygen treatment during walking on dyspnea and endurance in patients with COPD on LTOT.

Method: In a double blinded randomized crossover trial, 33 patients (21 women) performed two Endurance Shuttle Walk Tests (ESWT). One ESWT was performed using a closed-loop device, O2matic® to deliver a variable AOT set at an SpO2-target of 90 to 94% and a flow of 0-15 l/min. The other ESWT was performed using the usual fixed-dose oxygen treatment. The primary outcome was difference in BORG CR10 dyspnea scale in the ESWT at isotimes.

Results: The patients had a mean ±SD age of 72.7 ±6.5 years, FEV1 %pred. 31.9 ±11.3 and a home oxygen flow of 1.6 ±0.9 l/min. At last corresponding isotime in the ESWT, the patients reported dyspnea equal to 7.1 ±2.1 with fixed-dose and 4.3 ± 2.0 with AOT, p<0.001. The patients walked on average 6.29 ±3.62 min with fixed-dose and 10.92 ±5.12 min with AOT, p<0.001. AOT kept the patients in target SpO2 level for 56% of the time compared to 12% in the fixed-dose walk.

Conclusion: Dyspnea was significantly and clinically relevant reduced during walking when the oxygen level was maintained at SpO2>90%. Furthermore, endurance time increased significantly by 75% by using AOT compared to fixed-dose oxygen. Variable oxygen dosing during activity could lead to meaningful improvements in patients with COPD on LTOT.