Beat-to-beat Observation Of The Changes Of Ambulatory Blood Pressure During Sleep In Obstructive Sleep Apnea Patients

Objective To observe the dynamic changes of blood pressure during and after the apnea and observe the different of the changes among different sleep phases by beat-to beat. To investigate the related factors influencing the elevated systolic blood pressure index.Methods All subjects were recruited in Sleep Disorders Center at Beijing Chaoyang Hospital affiliated to Capital Medical University from May 2015 to November 2015. The demographic dates and Epworth sleepiness scale score were recorded and all subjects underwent PSG and ambulatory blood pressure monitoring by PTT, a continuous, non-invasive BP measurement.Result 103 subjects(five females and nighty-seven males) were conducted. The average AHI was 47.97 ± 27.46(means ± SD) times per hour. The median systolic blood pressure index was 29.27 times/h(the quarterback spacing of 50%), and the systolic blood pressure was 18.23 ± 4.05(means ± SD) mm Hg. We found that:(1)blood pressure fell by 2-7 mm Hg during the process of obstructive apnea. When the apnea ended, blood pressure increased rapidly, the average systolic blood pressure could rise by 18.17±4.05(means ± SD) mm Hg. Blood pressure declined to baseline after about 10 s.(2) Through the Spearman correlation analysis, we came to the conclusion that systolic blood pressure index was related to AHI(r = 0.659, p < 0.01).The multiple linear regression analysis showed that systolic blood pressure index =5.3 + 0.602*AHI + 0.260*total micro-arousal index-5.625*group of age.(3) REM sleep had higher blood pressure index than NONREM sleep, which did not change significantly. But the average systolic blood pressure were:131.01 ± 22.15 mm Hg vs124.33 ± 19.44 mm Hg,(p=0.008), and the MAP were: 98.31 ± 12.16 mm Hg vs 98.31± 12.16 mm Hg(p=0.04), they had different statistically. Comparing between the REM sleep and stage 3 sleep, we found that average AHI of REM sleep was significantly higher than that of 3 sleep, the average systolic blood pressure index was also increased significantly: 49.73 ± 45.35 times/h vs 26.69 ± 45.88 times/h(p <0.01). The average systolic blood pressure rise in value, the average systolic blood pressure, the MAP between of them were also different significantly.Conclusion 1. Patients with OSA had blood pressure fluctuations during the sleep.Blood pressure could decrease during the process of apnea, then a dramatic increase happened after the apnea; 2. AHI, total micro-arousal index and age were related to elevated systolic blood pressure index. Among of them, AHI was the strongest correlation to systolic blood pressure index; 3. The baseline of blood pressure(the average systolic blood pressure and the MAP) during the REM sleep was higher level than NONREM stage. The baseline of blood pressure of the stage 3 was the lowest; 4.The fluctuation of blood pressure(such as, systolic blood pressure index, the value of average elevated systolic blood pressure) during REM sleep did not change significantly than the fluctuation of NONREM stage, but increased significantly than the fluctuation of stage 3.