05372136 is referenced by 301 patents and cites 15 patents.

A system for determining the hematocrit transcutaneously and noninvasively. Disclosed are a finger clip assembly and an earlobe clip assembly, each including at least a pair of emitters and a photodiode in appropriate alignment to enable operation in either a transmissive mode or a reflectance mode. At least two, and preferably three, predetermined wavelengths of light are passed onto or through body tissues such as the finger, earlobe, or scalp, etc. and the extinction of each wavelength is detected. Mathematical manipulation of the detected values compensates for the effects of body tissue and fluid and determines the hematocrit value. If a fourth wavelength of light is used which is extinguished substantially differently by oxyhemoglobin and reduced hemoglobin and which is not substantially extinguished by plasma, then the blood oxygen saturation value, independent of hematocrit, may be determined.

It is also disclosed how to detect and analyze multiple wavelengths using a logarithmic DC analysis technique. Then a pulse wave is not required so, this method may be utilized in states of low blood pressure or low blood flow.

Title
System and method for noninvasive hematocrit monitoring
Application Number
598169
Publication Number
5372136
Application Date
February 1, 1993
Publication Date
December 13, 1994
Inventor
David H Harris
Ogden
UT, US
Robert R Steuer
Pleasant View
UT, US
Agent
Workman Nydegger & Jensen
Assignee
Noninvasive Medical Technology Corporation
UT, US
IPC
A61B 5/00
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