Photoplethysmography for non-invasive in vivo measurement of bone hemodynamics.

Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, USA. jmateus@alum.mit.edu

Physiological measurement 2012 Jun

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Developments in photoplethysmography (PPG) hardware make this device a promising tool for non-invasive deep-tissue hemodynamic measurements. The aim of this study was to validate the use of PPG as a tool for non-invasive bone hemodynamic measurements. A new PPG device capable of measuring bone hemodynamic responses was designed, tested and validated. Validation experiments included cold exposure, arterial occlusion, skin occlusion and nitroglycerin exposure. Cold exposure resulted in a decrease in skin perfusion (p = 0.011) and bone perfusion (p = 0.005); arterial occlusion also resulted in decreased skin perfusion (p < 0.001) and bone perfusion (p = 0.008), with arterial occlusion resulting in a greater decrease in perfusion than cold exposure. The independence of the skin and bone PPG signals was demonstrated by the ability to independently increase (p = 0.003) and decrease (p = 0.005) the skin signal without significantly affecting the bone signal. Our experiments build upon and expand previous PPG developments and validation studies. Our custom-made PPG hardware represents a state-of-the-art tool for non-invasive monitoring of deep tissues, and our data support the use of PPG as a valid tool for measuring bone hemodynamic responses in vivo.

Citation

Jaime Mateus, Alan R Hargens. Photoplethysmography for non-invasive in vivo measurement of bone hemodynamics. Physiological measurement. 2012 Jun;33(6):1027-42