National Center for Theoretical Sciences, National Taiwan University, Taipei 106, Taiwan.
Department of Applied Mathematics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan.
Physiol Meas. 2024 Sep 16;45(9). doi: 10.1088/1361-6579/ad7779.
We investigated fluctuations of the photoplethysmography (PPG) waveform in patients undergoing surgery. There is an association between the morphologic variation extracted from arterial blood pressure (ABP) signals and short-term surgical outcomes. The underlying physiology could be the numerous regulatory mechanisms on the cardiovascular system. We hypothesized that similar information might exist in PPG waveform. However, due to the principles of light absorption, the noninvasive PPG signals are more susceptible to artifacts and necessitate meticulous signal processing.Employing the unsupervised manifold learning algorithm, dynamic diffusion map, we quantified multivariate waveform morphological variations from the PPG continuous waveform signal. Additionally, we developed several data analysis techniques to mitigate PPG signal artifacts to enhance performance and subsequently validated them using real-life clinical database.Our findings show similar associations between PPG waveform during surgery and short-term surgical outcomes, consistent with the observations from ABP waveform analysis.The variation of morphology information in the PPG waveform signal in major surgery provides clinical meanings, which may offer new opportunity of PPG waveform in a wider range of biomedical applications, due to its non-invasive nature.
我们研究了手术患者的光体积描记图（PPG）波形的波动。从动脉血压（ABP）信号中提取的形态变化与短期手术结果之间存在关联。潜在的生理学机制可能是心血管系统的众多调节机制。我们假设类似的信息可能存在于 PPG 波形中。然而，由于光吸收的原理，非侵入性的 PPG 信号更容易受到伪影的影响，因此需要进行细致的信号处理。我们使用无监督流形学习算法——动态扩散图，从 PPG 连续波信号中量化了多变量波形形态变化。此外，我们还开发了几种数据分析技术来减轻 PPG 信号伪影，以提高性能，随后使用真实临床数据库对其进行了验证。我们的研究结果表明，手术期间 PPG 波形与短期手术结果之间存在类似的关联，与 ABP 波形分析的观察结果一致。主要手术中 PPG 波形信号形态信息的变化提供了临床意义，由于其非侵入性，可能为 PPG 波形在更广泛的生物医学应用中提供新的机会。
