Method for analyzing of dynamic cerebral autoregulation, and its significance : Comparable study and dynamic and static cerebral autoregulation on autoregulation curve.

1.数据采集：5例健康志愿者，经颅多普勒（TCD）测量动脉压、大脑中动脉血流速度（Vmca），同时通过AD转换器将心电图输入PC机。2.动态脑自动调节（dCAR）分析新方法的建立：在心电图的每个R峰处逐搏计算动脉压（MAP）和Vmca的平均值，然后以0.5Hz重采样。使用MAP和平均Vmca之间的传递函数分析dCAR。计算V相干性（coh）、增益和相位。在高碳酸血症（PetCO_2> 50 mmHg）时，COH <0.07Hz明显增高，在正常碳酸血症（PetCO_2：30- 40 mmHg）时恢复正常。3.静态自动调节曲线对dCAR的评价：（1）动物实验：5只成年猫，激光多普勒测定局部脑血流量（rCBF），TCD测定Vmca，同时测定ECG和MAP。通过静脉切开、输血或静脉滴注苯肾上腺素诱导MAP（40、70、100、120和180 mmHg）的阶梯性变化。在每个MAP下维持稳定条件5 min，并在每个MAP下评价dCAR。研究期间维持正常碳酸血症。（2）结果：MAP在70- 120 mmHg范围内，Vmca和rCBF均维持在正常水平，MAP为40 mmHg时Vmca和rCBF明显降低，MAP为180 mmHg时Vmca和rCBF明显升高（P<0.05）。与100 mmHg相比，MAP= 40 mmHg时<0.07Hz的coh显著增加，MAP= 180 mmHg时各频率的coh均显著增加（P<0.05）。因此，床旁评价dCAR是可行和可靠的。

1.Data Acquisition :Arterial pressure, blood flow velocity in the middle cerebral artery(Vmca) measured with transcranial Doppler(TCD), and ECG were simultaneously recorded into PC via AD converter in 5 adult volunteers.2.Development of new method for analyzing of dynamic cerebral autoregulation(dCAR) :Beat by beat mean values of arterial pressure (MAP) and Vmca were calculated, aligned at each R peak of ECG, and then resampled at 0.5Hz. dCAR was analyzed with using transfer function between MAP and mean Vmca. V Coherence (coh), gain, and phase were calculated. During hypercpnia (PetCO_2>50mmHg), coh <0.07Hz was significantly increased, and normalized during normocapnia ((PetCO_2:30-40mmHg). These results indicate that an increase of coh <0.07Hz may be reliable indicator of dCAR.3.Evaluation of dCAR on static autoregulation curve :(1)Animal study : Regional CBF(rCBF) measured with laser Doppler, Vmca measured with TCD,ECG,and MAP were simultaneously measured in 5 adult cats. Stepwise changes of MAP(40,70,100,120,and 180mmHg) were induced by phlebotomy, transfusion, or an infusion of phenylephrine. Steady condition was maintained at each MAP for 5min, and dCAR was evaluated at each MAP. Normocapnia was maintained during study.(2)Results :mean Vmca and rCBF were maintained in the range of MAP between 70-120mmHg, and significantly reduced at MAP of 40mmHg, and increased at MAP of 180mmHg(P<0.05 in both). As compared at 100mmHg, coh in <0.07Hz was significantly increased at MAP=40mmHg, and coh in all frequency was significantly increased at MAP=180mmHg (P<0.05 in both).4.Conclusion :An increase of coh <07Hz can clearly correlate with degree of impairment of static autoregulation. Thus, bed side evaluation of dCAR is feasible and reliable.