Background: The Sit-to-stand (STS) test evaluates functional capacity and postural control. Motor coordination during posture maintenance engages the prefrontal brain structure function; Thus, this study aimed to explore whether cerebral oxygenation and perfusion during STST is altered in non-hypoxemic COPD patients, compared to controls. 

Methods and Results: This is a prospective case-control study. Twenty-three individuals, 11 stable non-hypoxemic COPD patients (age 67±2) and 12 age- and BMI-matched controls with no history of smoking or airflow obstruction or major cardiovascular disease, participated. Individuals with balance or lower limb musculoskeletal problems were excluded. Cerebral oxygenation was continuously monitored using near-infrared spectroscopy (NIRS, Oxymon, Artinis). Following a 5-min rest, participants performed a 30-s STS test; a 3-min seated recovery followed. COPD patients had baseline FEV₁=58.3±12.2%, SPO₂ rest=96(3)% and SPO₂ at the end of 6MWT=92(2)%. During the STS, COPD patients, compared to controls, exhibited a significantly lower rise (p<0.05) in oxygenated hemoglobin (O₂Hb; 0.4±1.3 vs 1.5±1.1), and in total hemoglobin (tHb; 0.4±1.3 vs 1.5±1.4), with no significant differences in deoxygenated HB (-0.1±0.4 vs. 0.2±0.6) and Hb difference (0.6±1.4 vs 1.1±0.9) and performed a significantly lower number of STST repetitions vs. controls (13.5±2.0 vs 20.2±6.7).

Conclusion: Non-hypoxemic COPD patients present with impaired prefrontal cerebral oxygenation, compared to controls, which may interprent to COPD patients' worse functional performance during everyday life activities.

Acknowledgements: This protocol received a research grant from Hellenic Thoracic Society