[Oxygen saturation at rest, on exercise and during sleep in COPD patients undergoing pulmonary rehabilitation program. Two years prospective controlled study]

Abstract

The role of pulmonary rehabilitation (PR) in COPD patients is well established. However, the PR programs includes physical exercise that may deteriorate chronic hypoxemia. The objective of the study was to evaluate impact of a long term PR program on oxygen saturation at rest, on exercise and during sleep in COPD patients no receiving supplemental oxygenation. A two--year controlled study involved 27 rehabilitated (PR-COPD patients (6 females) aged 32-76 years, mean 58.1 years on average and 19 control (C-COPD patients (3 females) aged 58-83 years, mean 68. COPD patients participating in PR program patients were younger, had higher value of FVC and FEV1 and better results of METs during symptom-limited exercise test (ET, p = 0.007). They also had better results of transcutaneus oxygen saturation (SaO2) at rest (p = 0.02), a lower maximal decrease in SaO2 during ET(p = 0.003) and a higher value of medan SaO2 during (p = 0.02). Following PR program the number of METs achieved during ET increased in PR-COPD patients (p = 0.007) and did not change in C-COPD, p = NS. The SaO2 at rest did not change significantly in both groups. Maximal drop in SaO2 during ET decreased in PR-COPD patients (p = 0.02) and did not change in C-COPD(p = NS) group. Median SaO2 at sleep did not change in PR-COPD patients (p = NS) but it decreased in C-COPD patients (p = 0.02). The study indicates that long term PR does not deteriorate the resting diurnal hypoxaemia, it prevent COPD patients from time depending exacerbation of nocturnal hypoxaemia and can improve oxygen saturation on exertion. The results could be influenced by baseline differences between PR-COPD and C-COPD patients.