Riskin-Mashiah Shlomit, Belfort Michael A
Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas, USA.
Obstet Gynecol. 2004 Feb;103(2):294-8. doi: 10.1097/01.AOG.0000110250.48579.21.
To evaluate and compare the cerebrovascular autoregulation in pregnant normotensive and mild chronic hypertensive patients without preeclampsia.
Transcranial Doppler ultrasound was used to measure peak, end-diastolic, and mean velocities in the middle cerebral arteries of 34 normotensive and 17 mild chronic hypertensive women in the third trimester of pregnancy. Measurements were performed in the left lateral position at baseline, during 5% CO(2) inhalation, and during an isometric handgrip test. Mean pulsatility index, resistance index, and cerebral perfusion pressure at each time were compared using 2-way repeated measures analysis of variance. Using an alpha error of 5%, the statistical power to identify differences in middle cerebral artery indices in response to the two maneuvers was at least 90% and 50% in comparison between the two groups. Significance was P <.05.
Pregnant women with mild chronic hypertension had higher baseline mean blood pressure but similar pulsatility index (0.73 versus 0.75), resistance index (0.50 versus 0.50), and cerebral perfusion pressure (59.9 versus 61.8 mm Hg) compared with normotensive pregnant women. Both maneuvers caused a significant reduction in pulsatility index and resistance index and higher cerebral perfusion pressure. No significant differences were noted in the response to either 5% CO(2) inhalation or isometric handgrip test between the two groups.
Pregnant women with mild chronic hypertension show normal cerebral vasomotor reactivity to CO(2) breathing and isometric handgrip. This suggests that the abnormal cerebrovascular autoregulation in preeclampsia is not directly linked to the elevated blood pressure but rather is determined by a separate pathophysiologic pathway.
II-2
评估并比较未患先兆子痫的妊娠血压正常和轻度慢性高血压患者的脑血管自动调节功能。
采用经颅多普勒超声测量34例血压正常和17例轻度慢性高血压孕妇孕晚期大脑中动脉的峰值、舒张末期和平均血流速度。测量在基线、吸入5%二氧化碳期间和等长握力试验期间左侧卧位进行。每次测量时的平均搏动指数、阻力指数和脑灌注压采用双向重复测量方差分析进行比较。使用5%的α错误率，两组之间比较时，识别大脑中动脉指数对两种操作反应差异的统计功效至少为90%和50%。显著性水平为P<0.05。
与血压正常的孕妇相比，轻度慢性高血压孕妇的基线平均血压较高，但搏动指数（0.73对0.75）、阻力指数（0.50对0.50）和脑灌注压（59.9对61.8 mmHg）相似。两种操作均导致搏动指数和阻力指数显著降低，脑灌注压升高。两组之间对5%二氧化碳吸入或等长握力试验的反应未发现显著差异。
轻度慢性高血压孕妇对二氧化碳呼吸和等长握力表现出正常的脑血管舒缩反应。这表明先兆子痫中异常的脑血管自动调节并非直接与血压升高相关，而是由一条独立的病理生理途径决定。
II-₂
