脉搏波形态学研究及其在子痫前期的应用

Morphology of Photoplethysmography and Its Application in Preeclampsia

子痫前期是妊娠20周后出现的特有疾病,会导致血液系统、消化系统、神经系统等的异常改变,严重危害孕产妇和围生儿的健康.针对实际临床中存在的子痫前期检测方法复杂、不便于日常监护的问题,提出了基于光电容积脉搏波提取相关特征参数的方法.根据脉搏波下降支的形态特征及生理意义,提取出了新的特征参数——光电容积斜率指数(PSI),通过逐段分析下降支斜率来体现外周血管阻力、血管壁弹性等生理信息的细节变化.基于临床采集的50例孕妇(23名为子痫前期患者,27名为正常孕妇)的光电容积脉搏波数据,对PSI指数区分子痫前期患者与正常孕妇的有效性进行了验证.结果表明,真阳性20例,假阳性1例,真阴性26例,假阴性3例,灵敏性和特异性分别达到87.0%和96.3%,准确性达到92.0%.PSI指数为子痫前期的无创诊断研究提供了理论依据和新的研究方法,对于实现子痫前期的早期筛查、保障孕妇和胎儿的健康有着重要意义.

Preeclampsia(PE)is a disorder that may develop after 20 weeks of pregnancy,which could increase the risk of poor outcomes for both the mothers and the fetuses.Specifically,it could lead to abnormal changes in the hematologic,digestive,and nervous systems.As the diagnostic method of PE used in clinical practice is quite complex, there is an urge demand that a more convenient method should be proposed.In this thesis,a novel parameter extracted from the photoplethysmography (PPG) was proposed to improve the situation above.The new characteristic parameter,photoplethysmography slope index(PSI),was conducted from both the morphological features and the physiological significances of PPG.By analyzing the slope of a segmented descending curve,the diversity of the PPG was evaluated,which contained detailed physiological information including perivascular resistance and vascular wall elasticity.The ability of PSI to distinguish PE from normotensive pregnancies was also assessed in this thesis.The PSI was contrasted,which were calculated from the PPG data of 50 pregnancies (27 without and 23 with PE).The results revealed that there were 20 true positives,1 false positive,26 true negatives,and 3 false negatives.The receiver operating characteristic analysis indicated that the PSI could predict PE with a sensitivity of 87.0%,a specificity of 96.3%,and an accuracy of 92.0%.The PSI provided a new noninvasive method for PE diagnosis. It was suggested that PSI might be of significance for early PE screening and for the health of the mothers and fetuses.