CA2449621A1 - System and method for noninvasive hematocrit monitoring - Google Patents

System and method for noninvasive hematocrit monitoring Download PDF

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Publication number
CA2449621A1
CA2449621A1 CA002449621A CA2449621A CA2449621A1 CA 2449621 A1 CA2449621 A1 CA 2449621A1 CA 002449621 A CA002449621 A CA 002449621A CA 2449621 A CA2449621 A CA 2449621A CA 2449621 A1 CA2449621 A1 CA 2449621A1
Authority
CA
Canada
Prior art keywords
hematocrit
wavelength
earlobe
light
clip assembly
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CA002449621A
Other languages
French (fr)
Other versions
CA2449621C (en
Inventor
Robert R. Steuer
David B. Harris
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fresenius Medical Care Holdings Inc
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority claimed from CA002160252A external-priority patent/CA2160252C/en
Publication of CA2449621A1 publication Critical patent/CA2449621A1/en
Application granted granted Critical
Publication of CA2449621C publication Critical patent/CA2449621C/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/14535—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue for measuring haematocrit
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6813—Specially adapted to be attached to a specific body part
    • A61B5/6814—Head
    • A61B5/6815—Ear
    • A61B5/6816—Ear lobe
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6813—Specially adapted to be attached to a specific body part
    • A61B5/6825—Hand
    • A61B5/6826—Finger
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A61B5/14552—Details of sensors specially adapted therefor

Abstract

A system for determining the hematocrit transcutaneously and noninvasively. Disclosed are a finger clip assembly (6) and an earlobe clip assembly (10), each including at least a pair of emitters (1,2) and a photodiode (3) in appropriate alignment to enable operation in either a transmittion 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 (7), earlobe (11 ), 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, is determinable independently of the hematocrit value. It is also within the scope of the present invention to detect and analyze multiple wavelengths using a logarithmic DC analysis technique. In this embodiment, a pulse wave is not required. Hence, this embodiment may be utilized in states of low blood pressure or low blood flow.
CA002449621A 1993-04-12 1993-04-12 System and method for noninvasive hematocrit monitoring Expired - Lifetime CA2449621C (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA002160252A CA2160252C (en) 1993-04-12 1993-04-12 System and method for noninvasive hematocrit monitoring

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
CA002160252A Division CA2160252C (en) 1993-04-12 1993-04-12 System and method for noninvasive hematocrit monitoring

Publications (2)

Publication Number Publication Date
CA2449621A1 true CA2449621A1 (en) 1994-10-27
CA2449621C CA2449621C (en) 2009-09-15

Family

ID=4156736

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002449621A Expired - Lifetime CA2449621C (en) 1993-04-12 1993-04-12 System and method for noninvasive hematocrit monitoring

Country Status (1)

Country Link
CA (1) CA2449621C (en)

Also Published As

Publication number Publication date
CA2449621C (en) 2009-09-15

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