Song Yeongtak, Oh Jaehoon, Chee Youngjoon
1 School of Electrical Engineering, University of Ulsan , Ulsan, Korea.
Telemed J E Health. 2015 Jan;21(1):36-41. doi: 10.1089/tmj.2014.0051. Epub 2014 Nov 17.
Although many smartphone application (app) programs provide education and guidance for basic life support, they do not commonly provide feedback on the chest compression depth (CCD) and rate. The validation of its accuracy has not been reported to date. This study was a feasibility assessment of use of the smartphone as a CCD feedback device. In this study, we proposed the concept of a new real-time CCD estimation algorithm using a smartphone and evaluated the accuracy of the algorithm.
Using the double integration of the acceleration signal, which was obtained from the accelerometer in the smartphone, we estimated the CCD in real time. Based on its periodicity, we removed the bias error from the accelerometer. To evaluate this instrument's accuracy, we used a potentiometer as the reference depth measurement. The evaluation experiments included three levels of CCD (insufficient, adequate, and excessive) and four types of grasping orientations with various compression directions. We used the difference between the reference measurement and the estimated depth as the error. The error was calculated for each compression.
When chest compressions were performed with adequate depth for the patient who was lying on a flat floor, the mean (standard deviation) of the errors was 1.43 (1.00) mm. When the patient was lying on an oblique floor, the mean (standard deviation) of the errors was 3.13 (1.88) mm.
The error of the CCD estimation was tolerable for the algorithm to be used in the smartphone-based CCD feedback app to compress more than 51 mm, which is the 2010 American Heart Association guideline.
尽管许多智能手机应用程序提供基本生命支持的教育和指导，但它们通常不提供关于胸外按压深度（CCD）和速率的反馈。其准确性的验证迄今为止尚未见报道。本研究是对将智能手机用作CCD反馈设备的可行性评估。在本研究中，我们提出了一种使用智能手机的新型实时CCD估计算法的概念，并评估了该算法的准确性。
利用从智能手机中的加速度计获得的加速度信号的双重积分，我们实时估计了CCD。基于其周期性，我们消除了加速度计的偏差误差。为了评估该仪器的准确性，我们使用电位计作为参考深度测量。评估实验包括三种CCD水平（不足、足够和过度）以及四种具有不同按压方向的握持方向。我们将参考测量值与估计深度之间的差异用作误差。对每次按压计算误差。
对于躺在平坦地板上的患者进行足够深度的胸外按压时，误差的平均值（标准差）为1.43（1.00）mm。当患者躺在倾斜地板上时，误差的平均值（标准差）为3.13（1.88）mm。
对于基于智能手机的CCD反馈应用程序中使用的算法，要压缩超过51毫米（这是2010年美国心脏协会指南），CCD估计的误差是可以容忍的。
