Abstract
Obstructive sleep apnoea (OSA) is linked to increased cardiovascular risk. This risk can be reduced by nasal continuous positive airway pressure (nCPAP) treatment. Since OSA is associated with an increase of several vasoconstrictive factors we investigated whether nCPAP influences digital volume pulse wave .
We performed digital photoplethysmography during sleep at night in 94 consecutive patients who underwent polysomnography and 29 patients treated with nCPAP. Digital volume pulse waves were obtained investigator-independent and quantified using an algorithm for continuous automated analysis.
In patients with OSA and an apnoea-hypopnoea index of more than 10 per hour a significant vasoconstriction during the night was observed (p<0.0001 by Friedman test). A significant positive correlation existed between vasoconstriction and apnoea-hypopnoea index (Spearman correlation, r=0.27; p<0.01; n=94) and arousal index (Spearman correlation, r=0.21, p<0.05, n=94). After 6 month of nCPAP treatment the apnoea-hypopnoea index was significantly reduced from 27±3 per hour to 4±2 per hour (each n=29; p<0.001) and vasoconstriction during the night was significantly reduced from 10±3% to 3±1% (p<0.01).
We show changes in the reflective index during the night consistent with vasoconstriction in patients with OSA, which are significantly reduced after six month of nCPAP treatment.
- Digital volume pulse wave
- nasal continuous positive airway pressure
- obstructive sleep apnoea
- vasoconstriction
- ERS