睡眠時血圧の非観血的測定法の信頼性に関する検討

Evaluation about confidence of the non-invasive blood pressure measurement during sleep

　近年，高血圧診療上，24時間血圧測定の有用性が指摘されている。非観血的携帯型血圧計の軽量，小型化も進み一般臨床への応用が今後ますます普及すると思われる。非観血的血圧測定法は観血法と比べて安全で反復して測定できる等の長所がある。しかし，非観血的血圧測定法では，カフ圧の上昇，機械音等により，夜間の睡眠が妨げられ，血圧値の信頼性が疑問視されている。そこで本研究では，脳波による睡眠深度と血圧変動を同時に観察し，非観血的方法による睡眠時血圧の信頼性を検討した。

Since noninvasive blood pressure measurement may disturb sleep by Cuff's pressure on the arm or me-chanical sound, some investigators doubt the relia-bility of blood pressure measured by this method. We simultaneously observed the depth of sleep by Electoroencephalogram (EEG), eye movement, and variance of blood pressure to evaluate the reliability of noninvasive blood pressure measurement during sleep. The study was perfomed on 19 hospitalized subjects with untreated essential hypertension and 4 with normal blood pressure. Their age ranged from 28 to 68 years (the mean of 48. 8). Eleven subjectswore the Del Mar Avionics Pressurometer II Ambu-latory ECG and Blood pressure Recording System. Eight subjects wore Colin 203 x. Blood pressure and heart rate recordings were taken every 15 minutes in the daytime and every 30 minutes in the nighttime. The patients wore the instrument at 7 : 30 am, and moved into EEG room at 9 : 00 pm EEG, eye move-ment, blood pressure and heart rate were recorded at the same time till next morning. EEG was classified as REM and 1-4 stages according to APSS Classifi-cation. Type-A was designed as awaking due to blood pressure measurement. Type-B, as moving from a deep sleep to a light sleep without awaking. Type-C, as no change in deapth of sleep. Type-D, as awaking already when blood pressure was me-asured, after going to sleep (Dl) and before going to sleep (D 2). Incidence of type-A was 32. 8% (114/ 348), Type-B, 14. 7% (51/348), Type-C, 20. 4% (71/ 348), Type-D 1, 9. 5% (33/348), and TypeD-2, 22. 7 % (79/348). Noninvasive blood pressure measure-ment disturbed sleep in 47.4% of the occasion (A B). However blood pressure and heart rate in A and B were almost same as in C. Furthermore, blood pressures and heart rates in type-A, B, C, and D 1 were lower than in D 2. Therefore, it is suggested that the changes in the depth of sleep might not affect blood pressure so much, and that noninvasive blood pressure measurement during sleep might be comparatively reliable.