Disposable extracorporeal conduit for blood constituent monitoring
First Claim
1. A system for determining a concentration of a biologic constituent present in the blood of a patient undergoing a hemodialysis treatment, the hemodialysis treatment incorporating a dialyzer means for cleaning the blood of the patient, a pump means, and an input and an output catheter means for respectively conducting the blood of the patient from the patient to an input port of the dialyzer means and from an output port of the dialyzer means back to the patient, the pump means being for pumping the blood of the patient in a pulsatile fashion into the input port of the dialyzer through the input catheter means and out of the output port of the dialyzer means through the output catheter means, the system comprising:
- a. a first spectrophotometry means for defining a blood flow path, for emitting radiation into the blood in the flow path, and for detecting radiation passing through both the blood and the flow path, comprising;
i. cuvette means, in fluid communication with the dialyzer means, for defining a fluid passageway which contains and conducts therethrough the blood flowing in a pulsatile fashion, and comprising;
(1) an inlet;
(2) an outlet;
(3) a conduit, in fluid communication both between and with said inlet and outlet and being comprised of materials which permit transmission of electromagnetic radiation at a first and a second radiation wavelength therethrough, comprising;
(a) first and second opposed walls, having a predetermined separation therebetween, and constraining the pulsatile flowing fluid therebetween; and
(b) a transducer means, located in said first wall of said conduit, for varying said predetermined separation responsive to pressure pulsations in the fluid;
ii. emitter-sensor means for emitting radiation into the blood in the flow path, and for sensing radiation passing through both the blood and the cuvette means, comprising;
(1) emission means for directing radiation at said first and second wavelengths into the pulsatile flowing blood within the cuvette means, said emission means being situated so as to direct said radiation into the conduit of said cuvette means, said radiation directed by said emission means defining a directed radiation comprising;
(a) a first quantity of a radiation at said first radiation wavelength which, when directed into the flowing blood,(i) has a first extinguishment value which varies with the desired biologic constituent concentration in the flowing blood; and
(ii) has a second extinguishment value which varies with the concentration of components other than the desired biologic constituent in the flowing blood, which second extinguishment value is at least ten times smaller than said first extinguishment value; and
(b) a first quantity of a radiation at said second radiation wavelength, distinct from said first wavelength, which, when directed into the flowing blood;
(i) has a third extinguishment value which for varying concentrations in the flowing blood of the desired blood constituent is a non fixed multiple of said first extinguishment value; and
(ii) has a fourth extinguishment value which varies with the concentration of components other than the desired biologic constituent in the flowing blood, which fourth extinguishment value is at least ten times greater than said second extinguishment value;
(c) detection means for detecting the portion of said directed radiation which passes through both said conduit of said cuvette means and the pulsatile flowing blood therein, said detection means being situated so as to detect said radiation passing through the conduit of said cuvette means, the detected portion of each said directed radiation comprising;
(i) a second quantity of a radiation at the first radiation wavelength; and
(ii) a second quantity of a radiation at the second radiation wavelength; and
(2) calculation means, in electrical communication with said first spectrophotometry means, for determining the desired biologic constituent concentration by operating on the second quantities of the first and second radiation wavelengths.
7 Assignments
0 Petitions
Accused Products
Abstract
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.
68 Citations
15 Claims
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1. A system for determining a concentration of a biologic constituent present in the blood of a patient undergoing a hemodialysis treatment, the hemodialysis treatment incorporating a dialyzer means for cleaning the blood of the patient, a pump means, and an input and an output catheter means for respectively conducting the blood of the patient from the patient to an input port of the dialyzer means and from an output port of the dialyzer means back to the patient, the pump means being for pumping the blood of the patient in a pulsatile fashion into the input port of the dialyzer through the input catheter means and out of the output port of the dialyzer means through the output catheter means, the system comprising:
a. a first spectrophotometry means for defining a blood flow path, for emitting radiation into the blood in the flow path, and for detecting radiation passing through both the blood and the flow path, comprising; i. cuvette means, in fluid communication with the dialyzer means, for defining a fluid passageway which contains and conducts therethrough the blood flowing in a pulsatile fashion, and comprising; (1) an inlet; (2) an outlet; (3) a conduit, in fluid communication both between and with said inlet and outlet and being comprised of materials which permit transmission of electromagnetic radiation at a first and a second radiation wavelength therethrough, comprising; (a) first and second opposed walls, having a predetermined separation therebetween, and constraining the pulsatile flowing fluid therebetween; and (b) a transducer means, located in said first wall of said conduit, for varying said predetermined separation responsive to pressure pulsations in the fluid; ii. emitter-sensor means for emitting radiation into the blood in the flow path, and for sensing radiation passing through both the blood and the cuvette means, comprising; (1) emission means for directing radiation at said first and second wavelengths into the pulsatile flowing blood within the cuvette means, said emission means being situated so as to direct said radiation into the conduit of said cuvette means, said radiation directed by said emission means defining a directed radiation comprising; (a) a first quantity of a radiation at said first radiation wavelength which, when directed into the flowing blood, (i) has a first extinguishment value which varies with the desired biologic constituent concentration in the flowing blood; and (ii) has a second extinguishment value which varies with the concentration of components other than the desired biologic constituent in the flowing blood, which second extinguishment value is at least ten times smaller than said first extinguishment value; and (b) a first quantity of a radiation at said second radiation wavelength, distinct from said first wavelength, which, when directed into the flowing blood; (i) has a third extinguishment value which for varying concentrations in the flowing blood of the desired blood constituent is a non fixed multiple of said first extinguishment value; and (ii) has a fourth extinguishment value which varies with the concentration of components other than the desired biologic constituent in the flowing blood, which fourth extinguishment value is at least ten times greater than said second extinguishment value; (c) detection means for detecting the portion of said directed radiation which passes through both said conduit of said cuvette means and the pulsatile flowing blood therein, said detection means being situated so as to detect said radiation passing through the conduit of said cuvette means, the detected portion of each said directed radiation comprising; (i) a second quantity of a radiation at the first radiation wavelength; and (ii) a second quantity of a radiation at the second radiation wavelength; and (2) calculation means, in electrical communication with said first spectrophotometry means, for determining the desired biologic constituent concentration by operating on the second quantities of the first and second radiation wavelengths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
Specification