Diehl R R, Linden D, Lücke D, Berlit P
Department of Neurology, Alfried Krupp Hospital, Essen, Germany.
Stroke. 1995 Oct;26(10):1801-4. doi: 10.1161/01.str.26.10.1801.
This study investigates the usefulness, as a test of dynamic autoregulation, of phase shift angle analysis between oscillations in cerebral blood flow velocity (CBFV) and in arterial blood pressure (ABP) during deep breathing.
Fifty healthy volunteers, 20 patients with occlusive cerebrovascular diseases (OCD), and 10 patients with arteriovenous malformations (AVM) took part in the study. All subjects received transcranial Doppler monitoring of both middle cerebral arteries (MCAs). In addition, continuous blood pressure monitoring was performed with the use of noninvasive servo-controlled infrared finger plethysmography during deep breathing at a rate of 6/min. With the use of a high-pass filter model of autoregulation, autoregulation was quantified as phase shift angle between oscillations in CBFV and ABP at a frequency of 6/min. A phase shift angle of 0 degrees indicates total absence of autoregulation, while 90 degrees can be gauged as optimal autoregulation. In addition, vasomotor reactivity of both MCAs to CO2 stimulation was assessed among patients and calculated as percent increase in CBFV per millimeter of mercury of increase in CO2.
All normal subjects showed positive phase shift angles between CBFV and ABP (mean +/- SD, 70.5 +/- 29.8 degrees). OCD patients presented with significantly decreased phase shift angles for the MCA only on the pathological side (51.7 +/- 35.1 degrees; P < .05). Patients with AVM showed significantly reduced phase shift angles on both the affected side (26.8 +/- 13.5 degrees; P < .001) and the unaffected side (40.6 +/- 26.6 degrees; P < .01). In patients' groups, phase shift angle and vasomotor reactivity correlated significantly (r = .66; P < .001) after results from all MCAs were pooled.
Results confirm the high-pass filter model of cerebral autoregulation: Normal subjects showed predicted positive phase shift angles between CBFV and ABP oscillations. Patients with expected autoregulatory disturbances showed significant decreases in phase shift angles. Close correlations existed between autoregulation and CO2-induced vasomotor reactivity.
本研究旨在探讨深呼吸期间脑血流速度（CBFV）与动脉血压（ABP）振荡之间的相移角分析作为动态自动调节测试的实用性。
50名健康志愿者、20名闭塞性脑血管疾病（OCD）患者和10名动静脉畸形（AVM）患者参与了本研究。所有受试者均接受双侧大脑中动脉（MCA）的经颅多普勒监测。此外，在以每分钟6次的频率进行深呼吸期间，使用无创伺服控制红外手指体积描记法进行连续血压监测。使用自动调节的高通滤波器模型，将自动调节量化为CBFV和ABP在每分钟6次频率下振荡之间的相移角。0度的相移角表示完全没有自动调节，而90度可视为最佳自动调节。此外，在患者中评估了双侧MCA对CO2刺激的血管运动反应性，并计算为每毫米汞柱CO2增加时CBFV的增加百分比。
所有正常受试者在CBFV和ABP之间均表现出正相移角（平均值±标准差，70.5±29.8度）。OCD患者仅在病变侧的MCA呈现出明显降低的相移角（51.7±35.1度；P<.05）。AVM患者在患侧（26.8±13.5度；P<.001）和未患侧（40.6±26.6度；P<.01）均表现出明显降低的相移角。在患者组中，汇总所有MCA的结果后，相移角与血管运动反应性显著相关（r =.66；P<.001）。
结果证实了脑自动调节的高通滤波器模型：正常受试者在CBFV和ABP振荡之间表现出预测的正相移角。预期有自动调节障碍的患者表现出相移角显著降低。自动调节与CO2诱导的血管运动反应性之间存在密切相关性。
