Prevalence of Exercise-Induced Desaturation Among COPD Patients Enrolled in Early Inpatient Pulmonary Rehabilitation

Background: Acute exacerbations of COPD (AECOPDs) may cause exercise-induced desaturation (EID), affecting recovery and rehabilitation outcomes. The prevalence and clinical implications of EID during early postexacerbation pulmonary rehabilitation are unclear. This study aimed to determine the prevalence of EID in COPD patients recovering from AECOPDs, with and without long-term oxygen therapy (LTOT) at rest, and to compare clinical, functional, and physiological characteristics. Methods: This retrospective, multicenter study included 262 COPD patients admitted for inpatient pulmonary rehabilitation after AECOPDs. Participants were stratified by resting oxygen therapy status. EID was defined as a ≥4% fall in peripheral oxygen saturation from baseline with nadir <90% during the 6-minute walking test. Clinical, functional, and physiological parameters were compared across subgroups. Results: Overall, 132 patients (50.4%) exhibited EID. Prevalence was higher in patients on oxygen at rest (61.5%) than in those breathing room air (33.9%, p <0.0001). Patients on oxygen therapy had greater lung function impairment, reduced exercise capacity, and higher dyspnea-related disability. EID was associated with greater heart rate response in patients on supplemental oxygen but not consistently with perceived dyspnea or fatigue, highlighting the importance of objective oximetry during exercise testing. Regardless of EID, individuals on oxygen walked shorter distances than those on room air. Conclusions: EID is common in COPD patients recovering from AECOPD, especially those receiving LTOT, and is linked to more severe functional impairment. Systematic EID assessment using objective oximetry during early pulmonary rehabilitation may support individualized oxygen titration and exercise prescriptions. Prospective studies are needed to clarify its prognostic implications.