Short-term effects of non-invasive ventilation on cerebral blood flow and cognitive function in COPD

Abstract

Objectives: Investigate the acute effects of non-invasive ventilation (NIV) on cerebral blood flow (CBF) and on cognitive functions in COPD.

Methods: Nine non-hypercapnic stable COPD and twelve healthy controls were enrolled. CBF (transcranial Doppler), cognitive tests and cardiorespiratory response were performed at baseline, during one hour of NIV and after 30 min.

Results: Both groups had an increase in tidal volume and reduction in respiratory rate during NIV, but only controls showed PaCO₂ reductions (41.2 ± 4.6 to 36.5 ± 7.3 in controls vs. 40.9 ± 4.5 to 42.9 ± 5.9 in COPD). During NIV CBF was significantly reduced in healthy controls and COPD, although this effect was less pronounced in the latter. At the same time, healthy controls demonstrated an improvement in cognitive executive function compared to COPD in the Trail Making Test part B (90.5 vs. 180s; respectively).

Conclusion: NIV application for one hour reversibly reduced CBF in healthy controls and non-hypercapnic stable COPD patients, despite no significant reductions of the PaCO₂ in the latter group. It was associated with minor cognitive improvements in the executive function in healthy volunteers, but not in COPD.

Keywords: COPD; Cerebral blood flow; Cognitive function; Non-invasive ventilation.