Yan Iris Renfei, Poon Carmen Chung Yan, Zhang Yuan-Ting
Joint Research Center for Biomedical Engineering, Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong.
Blood Press Monit. 2009 Dec;14(6):257-67. doi: 10.1097/MBP.0b013e328330aea8.
The call for early detection of hypertension and cardiac events creates a heavy demand for devices that can be used for blood pressure (BP) monitoring at home and in ambulatory settings. An emerging type of BP monitors without an occluding cuff has drawn great attentions for this application because it is comfortable and capable of providing continuous readings. For the development the cuff-less devices, it is crucial for the clinicians and engineers to joint efforts in establishing an evaluation standard.
This study attempts to contribute to its initiation in two ways. First, a new distribution model for measurement differences between the test device and the reference was proposed. We verified the model using evaluation results from 40 devices, of which 80% of the American Association for the Advancement of Medical Instrumentation and British Hypertension Society reporting results were in agreement, as compared with 50%, if the original normal model was used. We further tested a cuff-less device on 85 patients for 999 datasets and found that the differences between the proposed distribution and that of the device were nonsignificant for systolic BP measurements (Kolmogorov-Smirnov = 0.036, P = 0.15). Second, some evaluation scales were studied for their capability to assess the accuracy of cuff-less devices. For mean absolute difference, a map was developed to relate it with the criteria of American Association for the Advancement of Medical Instrumentation, British Hypertension Society, and European Society of Hypertension protocols, on the basis of the proposed distribution model; for mean absolute percentage difference, it is prominent in evaluating devices that have measurement errors often increasing with BP, which is an issue has not been fully explored in existing standards.
This study focused on the statistical aspect of establishing standard to assess the accuracy of cuff-less BP measuring devices. The results of our study on the validation reports of various cuff-based devices and an experimental study on a cuff-less device showed that the t4 distribution is better than the normal distribution in portraying the underlying error distribution of both kinds of devices. Moreover, based on both the theoretical and experimental studies, mean absolute difference or mean absolute percentage difference is recommended as continuous scale to assess the accuracy of cuff-less devices for their own distinctive advantages.
对高血压和心脏事件进行早期检测的需求使得对可用于家庭和门诊血压（BP）监测的设备产生了巨大需求。一种新兴的无袖带血压监测仪因其舒适且能够提供连续读数而在该应用中备受关注。对于无袖带设备的开发，临床医生和工程师共同努力建立评估标准至关重要。
本研究试图通过两种方式为其启动做出贡献。首先，提出了一种用于测试设备与参考设备测量差异的新分布模型。我们使用40台设备的评估结果对该模型进行了验证，其中80%的美国医学仪器促进协会和英国高血压学会报告结果一致，而如果使用原始正态模型，这一比例为50%。我们进一步对85名患者的999个数据集测试了一种无袖带设备，发现所提出的分布与该设备的分布之间在收缩压测量方面差异不显著（柯尔莫哥洛夫-斯米尔诺夫检验=0.036，P=0.15）。其次，研究了一些评估量表评估无袖带设备准确性的能力。对于平均绝对差，基于所提出的分布模型开发了一张地图，将其与美国医学仪器促进协会、英国高血压学会和欧洲高血压学会方案的标准相关联；对于平均绝对百分比差，它在评估测量误差常随血压升高的设备方面表现突出，这是现有标准中尚未充分探讨的一个问题。
本研究聚焦于建立评估无袖带血压测量设备准确性标准的统计学方面。我们对各种基于袖带的设备验证报告以及对一种无袖带设备的实验研究结果表明，在描绘这两种设备的潜在误差分布方面，t4分布优于正态分布。此外，基于理论和实验研究，建议将平均绝对差或平均绝对百分比差作为连续量表来评估无袖带设备的准确性，因为它们具有各自独特的优势。
