Finžgar Miha, Podržaj Primož
Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia.
PeerJ. 2020 Jan 7;8:e8342. doi: 10.7717/peerj.8342. eCollection 2020.
Remote photoplethysmography (rPPG) is a promising non-contact measurement technique for assessing numerous physiological parameters: pulse rate, pulse rate variability (PRV), respiratory rate, pulse wave velocity, blood saturation, blood pressure, etc. To justify its use in ultra-short-term (UST) PRV analysis, which is of great benefit for several healthcare applications, the agreement between rPPG- and PPG-derived UST-PRV metrics was studied.
Three time-domain metrics-standard deviation of normal-to-normal (NN) intervals (SDNN), root mean square of successive NN interval differences (RMSSD), and the percentage of adjacent NN intervals that differ from each other by more than 50 ms (pNN50)-were extracted from 56 video recordings in a publicly available data set. The selected metrics were calculated on the basis of three groups of 10 s recordings and their average, two groups of 30 s recordings and their average, and a group of 60 s recordings taken from the full-length recordings and then compared with metrics derived from the corresponding reference (PPG) pulse waveform signals by using correlation and effect size parameters, and Bland-Altman plots.
The results show there is stronger agreement as the recording length increases for SDNN and RMSSD, yet there is no significant change for pNN50. The agreement parameters reach = 0.841 ( < 0.001), = 0.529 ( < 0.001), and = 0.657 ( < 0.001), estimated median bias -1.52, -2.28 ms and -1.95% and a small effect size for SDNN, RMSSD, and pNN50 derived from the 60 s recordings, respectively.
Remote photoplethysmography-derived UST-PRV metrics manage to capture UST-PRV metrics derived from reference (PPG) recordings well. This feature is highly desirable in numerous applications for the assessment of one's health and well-being. In future research, the validity of rPPG-derived UST-PRV metrics compared to the gold standard electrocardiography recordings is to be assessed.
远程光电容积脉搏波描记法（rPPG）是一种很有前景的非接触式测量技术，可用于评估多种生理参数：心率、心率变异性（PRV）、呼吸频率、脉搏波速度、血氧饱和度、血压等。为了证明其在超短期（UST）PRV分析中的应用价值（这对多种医疗应用大有裨益），我们研究了rPPG得出的UST-PRV指标与PPG得出的UST-PRV指标之间的一致性。
从一个公开数据集中的56个视频记录中提取了三个时域指标——正常到正常（NN）间期的标准差（SDNN）、连续NN间期差值的均方根（RMSSD）以及相邻NN间期相差超过50毫秒的百分比（pNN50）。所选指标基于从全长记录中选取的三组10秒记录及其平均值、两组30秒记录及其平均值以及一组60秒记录进行计算，然后通过使用相关性和效应大小参数以及布兰德-奥特曼图，将其与从相应参考（PPG）脉搏波形信号得出的指标进行比较。
结果表明，随着记录长度增加，SDNN和RMSSD的一致性更强，但pNN50没有显著变化。对于从60秒记录得出的SDNN、RMSSD和pNN50，一致性参数分别达到r = 0.841（p < 0.001）、r = 0.529（p < 0.001）和r = 0.657（p < 0.001），估计中位数偏差分别为-1.52、-2.28毫秒和-1.95%，且效应大小较小。
远程光电容积脉搏波描记法得出的UST-PRV指标能够很好地捕捉从参考（PPG）记录得出的UST-PRV指标。这一特性在众多评估个人健康和幸福的应用中非常理想。在未来的研究中，将评估与金标准心电图记录相比，rPPG得出的UST-PRV指标的有效性。
