Determination of liver function using the rate at which plasma disappears
OwnerAndreas Hoeftinventor
Life of this patent
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Abstract
A method and a device for determining liver function are described. Liver function is determined after injection of an indicator dye into the bloodstream, optical measurement of the resulting concentration of indicator dye in the bloodstream and calculation of a plasma elimination rate from the dye concentration-time curve of the indicator dye. An average circulation transit time mttcirc is calculated from the measurement of the dye concentration c(t). In addition, a parameter k representing a fractional reentry rate of the indicator dye after each pass through the circulation is determined. The plasma elimination rate PER is calculated according to the equation: PER=(1−k)/(k·mttcirc).
Claims12
A method of determining liver function of a patient having a circulation on the basis of plasma elimination rate (PER), comprising the steps of:
- (a) injecting an indicator dye into a bloodstream of said patient;
- (b) performing an optical measurement of a resulting concentration of indicator dye in the bloodstream;
- (c) calculating the plasma elimination rate (PER) from a dye concentration-time curve of the indicator dye;
- wherein calculating the plasma elimination rate (PER) includes:
- (i) calculating an average circulation transit time (mttcirc) from the measurement of the dye concentration (c(t));
- (ii) determining a parameter (k) representing a fractional reentry rate of the indicator dye after each pass through the circulation;
- and
- (iii) calculating the plasma elimination rate (PER) according to the equation
- PER=(1−k)/(k·mttcirc).
A device for determining liver function of a patient having a circulation on the basis of plasma elimination rate (PER), comprising:
- (a) an optical measurement sensor for determining an indicator dye concentration in a bloodstream of the patient resulting from an injection of indicator dye into the bloodstream;
- and
- (b) a computer for determining the plasma elimination rate (PER) from a dye concentration-time curve of the indicator dye,
- wherein the computer is controlled such that an average circulation transit time (mttcirc) is calculated from the measurement of the dye concentration (c(t));
- a parameter (k) representing a fractional reentry rate of the indicator dye after each pass through the circulation is determined, and the plasma elimination rate (PER) is calculated according to the equation
- PER=(1−k)/(k·mttcirc).
Dependencies are inferred from the claim text.