Institute of Medical Electronic Engineering in Medical School, Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
Physiol Meas. 2010 Mar;31(3):415-25. doi: 10.1088/0967-3334/31/3/009. Epub 2010 Feb 10.
Photoplethysmography (PPG) is an optical method for detecting blood volume changes in tissue. Respiratory-induced intensity, frequency and amplitude variations are contained in the PPG signal; thus, an understanding of the relationships between all of these variations and respiration is essential to advancing respiration monitoring based on PPG. This study investigated correlations between respiratory-induced variations extracted from PPG and simultaneous respiratory signals. PPG signals were recorded from 28 healthy subjects under eight different conditions. Six respiratory-induced variations, i.e. the period of the systole, diastole and pulse, the amplitude of the systole and diastole, and the intensity variation, were determined from the PPG signal. The results indicate that, compared with the period of the pulse, the period of the systole and diastole correlates weakly with respiration; the amplitude of the diastole has a stronger correlation with respiration than the amplitude of the systole. For men, when the respiratory rate is less than 10 breaths min(-1), the period of the pulse has the strongest correlation with respiration, whereas up to or above 15 breaths min(-1), the intensity variation becomes strongest in the sitting posture, while the amplitude of the diastole is strongest in the supine posture. For women, compared with the other variations, the period of the pulse has nearly the strongest correlation with respiration, independent of respiratory rate or posture.
光体积描记法（PPG）是一种用于检测组织中血液体积变化的光学方法。呼吸引起的 PPG 信号的强度、频率和幅度变化包含在 PPG 信号中；因此，了解所有这些变化与呼吸之间的关系对于基于 PPG 的呼吸监测的发展至关重要。本研究调查了从 PPG 中提取的呼吸诱导变化与同时的呼吸信号之间的相关性。从 28 名健康受试者在八种不同条件下记录了 PPG 信号。从 PPG 信号中确定了六个呼吸诱导变化，即收缩期、舒张期和脉搏周期、收缩期和舒张期幅度以及强度变化。结果表明，与脉搏周期相比，收缩期和舒张期周期与呼吸的相关性较弱；舒张期幅度与呼吸的相关性比收缩期幅度强。对于男性，当呼吸频率小于 10 次 min(-1)时，脉搏周期与呼吸的相关性最强，而当呼吸频率达到或超过 15 次 min(-1)时，坐姿时强度变化最强，而仰卧位时舒张期幅度最强。对于女性，与其他变化相比，脉搏周期与呼吸的相关性几乎最强，而与呼吸频率或姿势无关。
