Cerebral oximetry versus pulse photoplethysmography to monitor respiration rate

This study was conceived to analyze the possibility of monitoring the respiratory rate using oximetry signals obtained via Near-InfraRed Spectroscopy (NIRS) in the forehead, and to compare the results to those obtained using the photoplethysmography (PPG) signal. 29 subjects were enrolled in 30 min recording sessions at three controlled respiration rates: 9, 12 and 18 min
^-1
. Respiratory rate was estimated from the spectral analysis of the RR-interval time series derived from the NIRS and the PPG signals. The results show that respiratory rate was accurately determined using NIRS and PPG, although the precision was higher when PPG was used. Our results suggest that cerebral frontal lobe oximetry signals can be used for secondary analyses such as heart rate variability (HRV) when NIRS signals are sampled at high rates.