Lin Shyan-Lung, Yeh Shoou-Jeng, Chen Ching-Kun, Hsu Yu-Liang, Kuo Chih-En, Chen Wei-Yu, Hsieh Cheng-Pu
Department of Automatic Control Engineering, Feng Chia University, Taichung 40724, Taiwan.
Department of Neurology, Cheng Ching General Hospital, Taichung 41283, Taiwan.
J Clin Med. 2020 Dec 18;9(12):4088. doi: 10.3390/jcm9124088.
Postural orthostatic tachycardia syndrome (POTS) typically occurs in youths, and early accurate POTS diagnosis is challenging. A recent hypothesis suggests that upright cognitive impairment in POTS occurs because reduced cerebral blood flow velocity (CBFV) and cerebrovascular response to carbon dioxide (CO) are nonlinear during transient changes in end-tidal CO (P). This novel study aimed to reveal the interaction between cerebral autoregulation and ventilatory control in POTS patients by using tilt table and hyperventilation to alter the CO tension between 10 and 30 mmHg. The cerebral blood flow velocity (CBFV), partial pressure of end-tidal carbon dioxide (P), and other cardiopulmonary signals were recorded for POTS patients and two healthy groups including those aged >45 years (Healthy-Elder) and aged <45 years (Healthy-Youth) throughout the experiment. Two nonlinear regression functions, Models I and II, were applied to evaluate their CBFV-P relationship and cerebral vasomotor reactivity (CVMR). Among the estimated parameters, the curve-fitting Model I for CBFV and CVMR responses to CO for POTS patients demonstrated an observable dissimilarity in CBFV ( = 0.011), mid-P ( = 0.013), and P range ( = 0.023) compared with those of Healthy-Youth and in CBFV ( = 0.015) and CVMR compared with those of Healthy-Elder. With curve-fitting Model II for POTS patients, the fit parameters of curvilinear ( = 0.036) and P level ( = 0.033) displayed significant difference in comparison with Healthy-Youth parameters; range of change ( = 0.042), P level, and CBFV also displayed a significant difference in comparison with Healthy-Elder parameters. The results of this study contribute toward developing an early accurate diagnosis of impaired CBFV responses to CO for POTS patients.
体位性直立性心动过速综合征（POTS）通常发生在年轻人中，早期准确诊断POTS具有挑战性。最近的一种假说认为，POTS患者出现直立性认知障碍是因为在呼气末二氧化碳（P）的短暂变化过程中，脑血流速度（CBFV）和脑血管对二氧化碳（CO）的反应是非线性的。这项新研究旨在通过使用倾斜台和过度通气来改变二氧化碳张力在10至30 mmHg之间，揭示POTS患者脑自动调节与通气控制之间的相互作用。在整个实验过程中，记录了POTS患者以及两个健康组（包括年龄>45岁的健康老年人（Healthy-Elder）和年龄<45岁的健康年轻人（Healthy-Youth））的脑血流速度（CBFV）、呼气末二氧化碳分压（P）和其他心肺信号。应用两个非线性回归函数，模型I和模型II，来评估他们的CBFV-P关系和脑血管运动反应性（CVMR）。在估计参数中，与健康年轻人相比，POTS患者对CO的CBFV和CVMR反应的曲线拟合模型I在CBFV（=0.011）、P值中位数（=0.013）和P范围（=0.023）方面表现出明显差异，与健康老年人相比，在CBFV（=0.015）和CVMR方面也有差异。对于POTS患者使用曲线拟合模型II，曲线拟合（=0.036）和P水平（=0.033）的拟合参数与健康年轻人的参数相比显示出显著差异；变化范围（=0.042）、P水平和CBFV与健康老年人的参数相比也显示出显著差异。这项研究的结果有助于为POTS患者对CO的CBFV反应受损制定早期准确的诊断方法。
