An optical sensor includes photoemitter and photodetector elements at multiple spacings (d1, d2) for the purpose of measuring the bulk absorptivity (α) of an area immediately surrounding and including a hemodialysis access site, and the absorptivity (αo) of the tissue itself. At least one photoemitter...http://www.google.ca/patents/US6987993?utm_source=gb-gplus-sharePatent US6987993 - Sensor for transcutaneous measurement of vascular access blood flow
