Inan O T, Etemadi M, Paloma A, Giovangrandi L, Kovacs G T A
Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
Physiol Meas. 2009 Mar;30(3):261-74. doi: 10.1088/0967-3334/30/3/003. Epub 2009 Feb 6.
Cardiac ejection of blood into the aorta generates a reaction force on the body that can be measured externally via the ballistocardiogram (BCG). In this study, a commercial bathroom scale was modified to measure the BCGs of nine healthy subjects recovering from treadmill exercise. During the recovery, Doppler echocardiogram signals were obtained simultaneously from the left ventricular outflow tract of the heart. The percentage changes in root-mean-square (RMS) power of the BCG were strongly correlated with the percentage changes in cardiac output measured by Doppler echocardiography (R(2) = 0.85, n = 275 data points). The correlation coefficients for individually analyzed data ranged from 0.79 to 0.96. Using Bland-Altman methods for assessing agreement, the mean bias was found to be -0.5% (+/-24%) in estimating the percentage changes in cardiac output. In contrast to other non-invasive methods for trending cardiac output, the unobtrusive procedure presented here uses inexpensive equipment and could be performed without the aid of a medical professional.
心脏将血液射入主动脉会在身体上产生一个反作用力，该力可通过心冲击图（BCG）从外部进行测量。在本研究中，对一台商用浴室秤进行了改装，以测量九名从跑步机运动中恢复的健康受试者的心冲击图。在恢复过程中，同时从心脏的左心室流出道获取多普勒超声心动图信号。心冲击图的均方根（RMS）功率的百分比变化与通过多普勒超声心动图测量的心输出量的百分比变化密切相关（R² = 0.85，n = 275个数据点）。单独分析数据的相关系数范围为0.79至0.96。使用Bland-Altman方法评估一致性时，在心输出量百分比变化的估计中，平均偏差为-0.5%（±24%）。与其他用于监测心输出量的非侵入性方法不同，此处介绍的这种简便方法使用的设备价格低廉，且无需医疗专业人员协助即可进行。
