US 5,372,136 A · System and method for noninvasive hematocrit monitoring

A method for determining a desired biologic constituent concentration of the blood of a patient, the blood flowing in a pulsatile fashion in a body part of the patient or in an extracorporeal passageway in communication with the circulatory system of the patient so as to be subjectable to transcutaneous examination in the body part or to noninvasive examination in the extracorporeal passageway, the body part and the extracorporeal passageway defining a blood conduit and the method comprising the steps of:

(a) placing the blood conduit within a blood conduit receiving means with the blood flowing in the blood conduit;
(b) directing radiation into the flowing blood within the blood conduit using a radiation generation means situated within said blood conduit receiving means, said radiation defining a directed radiation comprising:
(i) a first quantity of a radiation at a first radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) has a first extinguishment value which varies with the desired biologic constituent concentration in the flowing blood and
(B) 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
(ii) a first quantity of a radiation at a second radiation wavelength, distinct from said first wavelength, which, when directed into the flowing blood within the blood conduit,
(A) 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
(B) 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) detecting the portion of said directed radiation which passes through both the blood conduit and the flowing blood therein using a radiation detection means situated within said blood conduit receiving means, said detected portion of 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;
(d) operating exclusively on the second quantities of the radiations at the first and second radiation wavelengths to determine the desired biologic constituent concentration.

10 more elements

A method for determining the hematocrit of the blood of a patient, the blood flowing in a pulsatile fashion in a body part of the patient or in an extracorporeal passageway in communication with the circulatory system of the patient so as to be subjectable to transcutaneous examination in the body part or to noninvasive examination in the extracorporeal passageway, the body part and the extracorporeal passageway defining a blood conduit and the method comprising the steps of:

(a) placing the blood conduit within a blood conduit receiving means with the flowing blood in the blood conduit;
(b) directing radiation into the flowing blood within the blood conduit using a radiation generation means situated within the blood conduit receiving means, said radiation defining a directed radiation comprising:
(i) a first quantity of a radiation at a first radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) has a first extinguishment value which varies with the hematocrit in the flowing blood and
(B) has a second extinguishment value which varies with the plasma in the flowing blood, which second extinguishment value is at least ten times smaller than said first extinguishment value;
and
(ii) a first quantity of radiation at a second radiation wavelength, distinct from said first wavelength, which, when directed into the flowing blood within the blood conduit,
(A) has a third extinguishment value which for varying hematocrit in the flowing blood is a non-fixed multiple of said first extinguishment value;
and
(B) has a fourth extinguishment value which varies with the plasma in the flowing blood, which fourth extinguishment value is at least ten times greater than said second extinguishment value;
(c) detecting the portion of said directed radiation which passes through both the blood conduit and the flowing blood therein with a radiation detection means situated within said conduit receiving means, said detected portion of 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;
(e) operating exclusively on the second quantities of the radiations at the first and second radiation wavelengths to determine the hematocrit of the patient.

11 more elements

A method for determining the hematocrit of the blood of a patient, the blood flowing in a pulsatile fashion in a body part of the patient or in an extracorporeal passageway in communication with the circulatory system of the patient so as to be subjectable to transcutaneous examination in the body part or to noninvasive examination in the extracorporeal passageway, the body part and the extracorporeal passageway defining a blood conduit and the method comprising the steps of:

(a) placing the blood conduit within a blood conduit receiving means with the flowing blood in the blood conduit;
(b) directing radiation into the flowing blood within the blood conduit using a radiation generation means situated within the blood conduit receiving means, said radiation defining a directed radiation comprising:
(i) a first quantity of a radiation at a first radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a first manner;
and
(ii) a first quantity of radiation at a second radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a second manner substantially different from said first manner;
(c) detecting the portion of said directed radiation which passes through both the blood conduit and the flowing blood therein with a radiation detection means situated within said conduit receiving means, said detected portion of said directed radiation comprising:
(i) a second quantity of a radiation at the first radiation wavelength being detected by steps comprising:
(A) determining the extinguishment of the total first radiation wavelength;
(B) determining a first radiation wavelength pulsatile value representing the difference between the maximum and the minimum extinguishment of a pulsatile component of the first radiation wavelength;
(C) determining the ratio between the first radiation wavelength pulsatile value and the extinguishment of the total first radiation wavelength over a period of time;
and
(D) determining a first mean ratio value over a period of time of the ratio between the first radiation wavelength pulsatile component and the average extinguishment of the first radiation wavelength, and
(ii) a second quantity of a radiation at the second radiation wavelength;
and
(d) operating on the second quantities of the radiations at the first and second radiation wavelengths to determine the hematocrit of the patient.

16 more elements

A method for determining the hematocrit of the blood of a patient, the blood flowing in a pulsatile fashion in a body part of the patient or in an extracorporeal passageway in communication with the circulatory system of the patient so as to be subjectable to transcutaneous examination in the body part or to noninvasive examination in the extracorporeal passageway, the body part and the extracorporeal passageway defining a blood conduit and the method comprising the steps of:

(a) placing the blood conduit within a blood conduit receiving means with the flowing blood in the blood conduit;
(b) directing radiation into the flowing blood within the blood conduit using a radiation generation means situated within the blood conduit receiving means, said radiation defining a directed radiation comprising:
(i) a first quantity of a radiation at a first radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a first manner;
and
(ii) a first quantity of radiation at a second radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a second manner substantially different from said first manner;
(c) detecting the portion of said directed radiation which passes through both the blood conduit and the flowing blood therein with a radiation detection means situated within said conduit receiving means, said detected portion of 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 being detected by steps comprising:
(A) determining the extinguishment of the total first radiation wavelength;
(B) determining a first radiation wavelength pulsatile value representing the true time derivative of a pulsatile component of the first radiation wavelength;
(C) determining the ratio between the first radiation wavelength pulsatile value and the extinguishment of the total first radiation wavelength over a period of time;
and
(D) determining a first mean ratio value over a period of time of the ratio between the first radiation wavelength pulsatile component and the average extinguishment of the first radiation wavelength;
and
(d) operating on the second quantities of the radiations at the first and second radiation wavelengths to determine the hematocrit of the patient.

16 more elements

A method for determining the hematocrit of the flowing blood of a patient, the flowing blood including a competing biologic constituent relative to the hemoglobin in the blood, the blood flowing in a pulsatile fashion in a body part of the patient or in an extracorporeal passageway in communication with the circulatory system of the patient so as to be subjectable to transcutaneous examination in the body part or to noninvasive examination in the extracorporeal passageway, the body part and the extracorporeal passageway defining a blood conduit and the method comprising the steps of:

(a) placing the blood conduit within a blood conduit receiving means with the flowing blood in the blood conduit;
(b) directing radiation into the flowing blood within the blood conduit using a radiation generation means situated within the blood conduit receiving means, said radiation defining a directed radiation comprising:
(i) a first quantity of a radiation at a first radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a first manner;
(ii) a first quantity of radiation at a second radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a second manner substantially different from said first manner;
and
(iii) a first quantity of a radiation at a third radiation wavelength, which when directed into the flowing blood in the blood conduit,
(A) is extinguished by the competing biologic constituent in the flowing blood in a manner characteristic of the competing biologic constituent;
and
(B) is extinguished by the constituents of the flowing blood other than the competing biologic constituent in a third manner, said third manner being substantially different from one of said first and second manners;
(c) detecting the portion of said directed radiation which passes through both the blood conduit and the flowing blood therein with a radiation detection means situated within said conduit receiving means, said detected portion of said directed radiation comprising:
(i) a second quantity of a radiation at the first radiation wavelength,
(ii) a second quantity of a radiation at the second radiation wavelength, and
(iii) a second quantity of a radiation at the third radiation wavelength being detected by steps comprising:
(A) determining the extinguishment of the total third radiation wavelength;
(B) determining a third radiation wavelength pulsatile value representing the difference between the maximum and the minimum extinguishment of a pulsatile component of the third radiation wavelength;
(C) determining the ratio between the third radiation wavelength pulsatile value and the extinguishment of the total third radiation wavelength over a period of time;
(D) determining a third mean ratio value over a period of time of the ratio between the third radiation wavelength pulsatile component and the average extinguishment of the third radiation wavelength;
and
(d) operating on the second quantities of the radiations at the first and second and third radiation wavelengths to determine the corrected hematocrit of the patient by determining the hematocrit of the patient by the combination of the first, second, and third mean ratio values.

20 more elements

A method for determining the hematocrit of the flowing blood of a patient, the flowing blood including a competing biologic constituent relative to the hemoglobin in the blood, the blood flowing in a pulsatile fashion in a body part of the patient or in an extracorporeal passageway in communication with the circulatory system of the patient so as to be subjectable to transcutaneous examination in the body part or to noninvasive examination in the extracorporeal passageway, the body part and the extracorporeal passageway defining a blood conduit and the method comprising the steps of:

(a) placing the blood conduit within a blood conduit receiving means with the flowing blood in the blood conduit;
(b) directing radiation into the flowing blood within the blood conduit using a radiation generation means situated within the blood conduit receiving means, said radiation defining a directed radiation comprising:
(i) a first quantity of a radiation at a first radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a first manner;
(ii) a first quantity of radiation at a second radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a second manner substantially different from said first manner;
and
(iii) a first quantity of a radiation at a third radiation wavelength, which when directed into the flowing blood in the blood conduit,
(A) is extinguished by the competing biologic constituent in the flowing blood in a manner characteristic of the competing biologic constituent;
and
(B) is extinguished by the constituents of the flowing blood other than the competing biologic constituent in a third manner, said third manner being substantially different from one of said first and second manners;
(c) detecting the portion of said directed radiation which passes through both the blood conduit and the flowing blood therein with a radiation detection means situated within said conduit receiving means, said detected portion of said directed radiation comprising:
(i) a second quantity of a radiation at the first radiation wavelength,
(ii) a second quantity of a radiation at the second radiation wavelength, and
(iii) a second quantity of a radiation at the third radiation wavelength being detected by steps comprising:
(A) determining the extinguishment of the total third radiation wavelength;
(B) determining a third radiation wavelength pulsatile value representing the true time derivative of a pulsatile component of the third radiation wavelength;
(C) determining the ratio between the third radiation wavelength pulsatile value and the extinguishment of the total third radiation wavelength over a period of time;
(D) determining a third mean ratio value over a period of time of the ratio between the third radiation wavelength pulsatile component and the average extinguishment of the third radiation wavelength;
and
(d) operating on the second quantities of the radiations at the first and second and third radiation wavelengths to determine the corrected hematocrit of the patient by determining the hematocrit of the patient by the combination of the first, second, and third mean ratio values.

20 more elements

A method for determining the hematocrit of the flowing blood of a patient, the flowing blood including a competing biologic constituent relative to the hemoglobin in the blood, the blood flowing in a pulsatile fashion in a body part of the patient or in an extracorporeal passageway in communication with the circulatory system of the patient so as to be subjectable to transcutaneous examination in the body part or to noninvasive examination in the extracorporeal passageway, the body part and the extracorporeal passageway defining a blood conduit and the method comprising the steps of:

(a) placing the blood conduit within a blood conduit receiving means with the flowing blood in the blood conduit;
(b) directing radiation into the flowing blood within the blood conduit using a radiation generation means situated within the blood conduit receiving means, said radiation defining a directed radiation comprising:
(i) a first quantity of a radiation at a first radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a first manner;
(ii) a first quantity of radiation at a second radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a second manner substantially different from said first manner;
(iii) a first quantity of a radiation at a third radiation wavelength, which when directed into the flowing blood in the blood conduit,
(A) is extinguished by the competing biologic constituent in the flowing blood in a manner characteristic of the competing biologic constituent;
and
(B) is extinguished by the constituents of the flowing blood other than the competing biologic constituent in a third manner, said third manner being substantially different from one of said first and second manners;
and
(iv) a first quantity of a radiation at a fourth radiation wavelength, distinct from said first, second and third radiation wavelengths, and which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially differently by oxyhemoglobin and by reduced oxyhemoglobin in the flowing blood, and which
(B) is not substantially extinguished by the plasma in the flowing blood;
(c) detecting the portion of said directed radiation which passes through both the blood conduit and the flowing blood therein with a radiation detection means situated within said conduit receiving means, said detected portion of said directed radiation comprising:
(i) a second quantity of a radiation at the first radiation wavelength,
(ii) a second quantity of a radiation at the second radiation wavelength,
(iii) a second quantity of a radiation at the third radiation wavelength, and
(iv) a second quantity of a radiation at the fourth radiation wavelength;
(d) operating on the second quantities of the radiations at the first and second radiation wavelengths to determine the hematocrit of the patient;
(e) determining the blood oxygen content value by the second quantities of the first, second, third, and fourth radiation wavelengths;
and
(f) displaying the blood oxygen content value.

22 more elements

A method for determining the hematocrit of the blood of a patient, the blood flowing in a pulsatile fashion in a body part of the patient or in an extracorporeal passageway in communication with the circulatory system of the patient so as to be subjectable to transcutaneous examination in the body part or to noninvasive examination in the extracorporeal passageway, the body part and the extracorporeal passageway defining a blood conduit and the method comprising the steps of:

(a) placing the blood conduit within a blood conduit receiving means with the flowing blood in the blood conduit;
(b) directing radiation into the flowing blood within the blood conduit using a radiation generation means situated within the blood conduit receiving means, said radiation defining a directed radiation comprising:
(i) a first quantity of a radiation at a first radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a first manner;
and
(ii) a first quantity of radiation at a second radiation wavelength which, when directed into the flowing blood within the blood conduit,
(A) is extinguished substantially the same amount by oxyhemoglobin and reduced hemoglobin in the flowing blood and
(B) is extinguished by the plasma in the flowing blood in a second manner substantially different from said first manner;
(c) detecting the portion of said directed radiation which passes through both the blood conduit and the flowing blood therein with a radiation detection means situated within said conduit receiving means, said detected portion of 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;
(d) operating on the second quantities of the radiations at the first and second radiation wavelengths to determine the hematocrit of the patient by determining the logarithmic intensity ratio of the second quantities of the first and the second radiation wavelengths.

10 more elements

System and method for noninvasive hematocrit monitoring

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System and method for noninvasive hematocrit monitoring

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Abstract

Claims48