In-line Diagnostics Corporation

Hema Metrics, Inc.

Noninvasive Medical Technology Corporation

David H Harris

Robert R Steuer

Malcolm Gray-Stephens

A system determines heamtocrit 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 assed 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 plasmas, then the blood oxygen saturation value, independent of hematocrit, maybe 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.

System for noninvasive hematocrit monitoring

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.

A disposable cuvette through which to pass pulsatile flowing blood. The cuvette has a conduit with two opposed walls having a predetermined separation therebetween that varies with each pulse of the flowing blood. A sealed air pocket damps the variation of the predetermined separation. The conduit is comprised of materials which permit passage therethrough of wavelengths of selected electromagnetic radiation. The radiation is emitted from a photoemitter which, and after passing through the cuvette, is detected by a photodetector. The quantities of detected radiation are operated on by a computer which uses a spectrophotometry technique to derive therefrom a blood constituent concentration value. Preferably, both cuvette and spectrophotometry technique are used during hemodialysis to derive changes in the hematocrit value of the blood of a dialyzed patient, thereby to deduce therefrom changes in the blood volume of the patient during dialysis. The technique enables a clinician to monitor a desired biologic constituent concentration value, such as the hematocrit, oxygen saturation, or oxygen content values by deriving and displaying the same as digital values in real time.

Disposable extracorporeal conduit for blood constituent monitoring

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.

Growing community of inventors

Ogden, UT, United States of America

David H Harris