Modulation of finger photoplethysmographic traces during forced respiration: venous blood in motion?
Photoplethysmographic (PPG) signals were recorded from the fingers of 10 healthy volunteers during forced respiratory inspiration. The aim of this pilot study was to assess the effect of negative airway pressure on the blood volumes within the tissue bed of the finger, and the resultant modulation of PPG signals. The acquired signals were analysed and oxygen saturations estimated from the frequency spectra in the cardiac and respiratory frequency ranges. Assuming that respiratory modulation affects blood volumes in veins to a greater extent than in arteries, the local venous oxygen saturation was estimated. Estimated venous oxygen saturation was found to be 3.1% (±4.2%) lower than the estimated arterial saturation.
School of Engineering and Mathematical Sciences, City University London, EC1V 0HB, UK. Justin.Phillips.1@city.ac.uk
Justin P
JP
Phillips
Alla
A
Belhaj
Kamran
K
Shafqat
Richard M
RM
Langford
Kirk H
KH
Shelley
Panayiotis A
PA
Kyriacou
D000328:Adult; D001775:Blood Circulation / Q000502:physiology*; D005260:Female; D005385:Fingers / Q000098:blood supply*; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D010092:Oximetry; D010100:Oxygen / Q000378:metabolism; D017156:Photoplethysmography; D011312:Pressure; D012119:Respiration; D012137:Respiratory System; D013147:Spirometry; D014680:Veins / Q000502:physiology*
D010100:Oxygen