2015 Volume 4 Pages 1-6
The maximum cross-correlation coefficient (ρmax) between blood pressure (BP) and heart rate (HR) variability for frequency components limited to the Mayer wave-related band is useful for the evaluation of baroreflex function. However, continuous BP measurement with an expensive and bulky measuring device is required to calculate ρmax. This study proposes a simpler method to obtain ρmax using a green light photoplethysmogram (PPG). A green PPG sensor is less affected by motion artifacts than a near-infrared PPG sensor. In this study, an electrocardiogram, continuous BP, green PPG, and near-infrared PPG were obtained from the subjects. HR, mean BP, and pulse transit time were estimated from the signals, and ρmax was subsequently calculated. Compared to the ρmax obtained from the near-infrared PPG signal, the ρmax obtained from the green PPG signal is closer in value to the ρmax obtained from mean BP. These results show that the green PPG sensor can be used to estimate baroreflex function instead of using continuous BP measurement.
