Nocturnal blood pressure during apnoeic and ventilatory periods in patients with obstructive sleep apnoea

The exact nature of asleep blood pressure in relation to awake blood pressu re is still unclear in patients with obstructive sleep apnoea. This study a imed: 1) to investigate the asleep blood pressure in both apnoeic and venti latory periods; 2) to determine the diurnal and nocturnal factors correlate d with the changes in blood pressure from apnoea to ventilatory periods dur ing sleep. Thirty-two patients, newly diagnosed as moderate to severe obstructive slee p apnoea with a standard nocturnal polysomnography, were enrolled. The bloo d pressure was monitored by using the noninvasive continuous monitoring met hod during polysomnographic study. The mean blood pressures in ventilatory periods during nonrapid eye movemen t (NREM) and rapid eye movement (REM) sleep were 117.5+/-17.9 mmHg and 128. 8+/-21.9 mmHg, and those in apnoea periods were 94.5+/-15.4 mmHg and 102.7/-19.0 mmHg. The average blood pressure during NREM sleep (103.0+/-16.1 mmH g) was higher than the awake blood pressure (97.0+/-15.7 mmHg). The blood p ressure during REM sleep was greater than that during NREM sleep. The chang es in the nocturnal blood pressure from apnoea to ventilatory periods were inversely correlated with the age and nocturnal mean nadir saturation. In conclusion, patients with obstructive sleep apnoea have higher asleep bl ood pressure than awake blood pressure.