DC Component of Green PPG from Earlobe Correlates with Mean Arterial Pressure in Resting Supine Subjects

Daily monitoring of mean arterial pressure (MAP) is required for patients with ventricular assisted device (VAD), who mostly have little pulsatile amplitude in the blood flow. To explore potential indices for estimating MAP, we analyzed photoplethysmogram (PPG) waveform obtained using green (560 nm) wavelength from the earlobe in five healthy subjects. In the setting of resting supine position with 8.5-minutes duration including 0.5-minutes cold test, we found distinct correlation (> 0.7) between DC component of the PPG waveform (DCGr) and MAP in all subjects (mean r=0.765±0.044). Meanwhile, both of pulse arrival time (PATGr) nor pulse amplitude divided by the DC component (mNPVGr) of the green PPG indicated no correlation to MAP (r=-0.136±0.241 and r=-0.150±0.478) in the same setting.