Method and apparatus for monitoring metabolism in body organs
Apparatus for calculating cardiac output
Method and apparatus for radiolabeling red blood cells
Blood constituent measuring device and method
Automated multi-point blood volume analyzer
Method for optically inspecting human body and apparatus for the same
Electromagnetic method and apparatus to measure constituents of human or animal tissue
ApplicationNo. 261634 filed on 06/17/1994
US Classes:600/431, Detectable material placed in body356/39, BLOOD ANALYSIS600/328Hemoglobin
ExaminersPrimary: Kamm, William E.
Assistant: Casler, Brian L.
Attorney, Agent or Firm
International ClassA61B 006/00
AbstractThe method of noninvasively measuring concentration of a dye in a circulatory system includes measuring an optical density of an arterial blood-dye mixture in an artery as a function of time at a wavelength Γ1 and at another different wavelength Γ2 ; calculating ratios of optical density at the wavelength Γ1 to that at wavelength Γ2 of arterial blood in the artery at a time before a predetermined initial time and of the arterial blood-dye mixture at at least one time t after the predetermined initial time; injecting a dye absorbing electromagnetic radiation at at least one of the wavelengths into the circulatory system at the predetermined initial time, t=0, to form the arterial blood-dye mixture; measuring a hemoglobin concentration in a blood sample from the living organism; and calculating a concentration C(d,t) of the dye in the arterial blood-dye mixture as a function of time, t, from the hemoglobin concentration, Hb; from extinction coefficients, &3xb5;d1 and &3xb5;d2, of the dye at the wavelengths Γ1 and Γ2 ; and from the ratio R(0) at the time before the predetermined initial time and the ratio R(t) at the at least one time, t according to the following formula: ##EQU1## wherein &3xb5;r1 and &3xb5;r2 are reduced hemoglobin extinction coefficients at wavelengths Γ1 and Γ2 respectively and &3xb5;o1 and &3xb5;o2 are oxyhemoglobin extinction coefficients at wavelengths Γ1 and Γ2 respectively.