Method and apparatus for noninvasively measuring concentration of a dye in arterial blood
First Claim
1. Method of noninvasively measuring concentration of a dye in a circulatory system of a living organism, said method comprising the steps of:
- a) measuring an optical density of an arterial blood flowing in an artery of the living organism at a wavelength Γ
1 and at another wavelength Γ
2 and at a time before a predetermined initial time;
b) injecting a dye absorbing electromagnetic radiation at at least one of said wavelengths into the circulatory system of the living organism at said predetermined initial time to form an arterial blood-dye mixture;
c) measuring an optical density of said arterial blood-dye mixture flowing in said artery at said wavelength Γ
1 and at said wavelength Γ
2 and at at least one time after said predetermined initial time;
d) calculating a ratio of said optical density of said arterial blood at said wavelength Γ
1 to said optical density of said arterial blood at said wavelength Γ
2 at said time before said predetermined initial time and a ratio of said optical density of said arterial blood-dye mixture at said wavelength Γ
1 to said optical density of said arterial blood-dye mixture at said wavelength Γ
2 at said at least one time after said predetermined initial time;
e) measuring a hemoglobin concentration in a blood portion from said living organism; and
f) calculating a concentration of said dye in said arterial blood-dye mixture at said at least one time after said predetermined initial time from said hemoglobin concentration determined by said measuring in step e), from extinction coefficients of said dye at said wavelength Γ
1 and at said other wavelength Γ
2 and from said ratios as calculated in step d) at said time before said predetermined initial time and at said at least one time after said predetermined initial time.
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Abstract
The 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, εd1 and εd2, 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 εr1 and εr2 are reduced hemoglobin extinction coefficients at wavelengths Γ1 and Γ2 respectively and εo1 and εo2 are oxyhemoglobin extinction coefficients at wavelengths Γ1 and Γ2 respectively.
138 Citations
18 Claims
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1. Method of noninvasively measuring concentration of a dye in a circulatory system of a living organism, said method comprising the steps of:
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a) measuring an optical density of an arterial blood flowing in an artery of the living organism at a wavelength Γ
1 and at another wavelength Γ
2 and at a time before a predetermined initial time;b) injecting a dye absorbing electromagnetic radiation at at least one of said wavelengths into the circulatory system of the living organism at said predetermined initial time to form an arterial blood-dye mixture; c) measuring an optical density of said arterial blood-dye mixture flowing in said artery at said wavelength Γ
1 and at said wavelength Γ
2 and at at least one time after said predetermined initial time;d) calculating a ratio of said optical density of said arterial blood at said wavelength Γ
1 to said optical density of said arterial blood at said wavelength Γ
2 at said time before said predetermined initial time and a ratio of said optical density of said arterial blood-dye mixture at said wavelength Γ
1 to said optical density of said arterial blood-dye mixture at said wavelength Γ
2 at said at least one time after said predetermined initial time;e) measuring a hemoglobin concentration in a blood portion from said living organism; and f) calculating a concentration of said dye in said arterial blood-dye mixture at said at least one time after said predetermined initial time from said hemoglobin concentration determined by said measuring in step e), from extinction coefficients of said dye at said wavelength Γ
1 and at said other wavelength Γ
2 and from said ratios as calculated in step d) at said time before said predetermined initial time and at said at least one time after said predetermined initial time. - View Dependent Claims (2, 3, 4)
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5. Method of noninvasively measuring concentration of a dye in a circulatory system of a living organism, said method comprising the steps of:
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a) measuring an optical density of an arterial blood flowing in an artery of the living organism at a wavelength Γ
1 and at another wavelength Γ
2 and at a time before a predetermined initial time;b) injecting a dye absorbing electromagnetic radiation at at least one of said wavelengths into the circulatory system of the living organism at said predetermined initial time to form an arterial blood-dye mixture; c) measuring an optical density of said optical density of said arterial blood-dye mixture flowing in said artery at said wavelength Γ
1 and at said wavelength Γ
2 and at at least one time after said predetermined initial time;d) calculating a ratio of said optical density of said arterial blood at said wavelength Γ
1 to said optical density of said arterial blood at said wavelength Γ
2 at said time before said predetermined initial time and a ratio of said optical density of said arterial blood-dye mixture at said wavelength Γ
1 to said optical density of said arterial blood-dye mixture at said wavelength Γ
2 at said at least one time after said predetermined initial time;e) measuring a hemoglobin concentration, Hb, in a blood sample from said living organism; f) calculating an oxyhemoglobin concentration, C(O), and a reduced hemoglobin concentration, C(r), in said arterial blood at said time before said initial predetermined time according to the following formulae;
##EQU13## wherein ε
ri =an extinction coefficient of reduced hemoglobin at said wavelength Γ
i where i=1 or 2,ε
oi =an extinction coefficient of oxyhemoglobin at said wavelength Γ
i where i=1 or 2, andg) calculating an oxygen saturation, O2Sat(0), in said arterial blood at said time before said predetermined initial time, wherein said oxygen saturation, O2Sat(0), is equal to C(O)/{C(O)+C(r)}; and h) calculating a concentration of said dye in said arterial blood-dye mixture at said at least one time after said predetermined initial time from said hemoglobin concentration, Hb;
said oxygen saturation, O2Sat(0);
extinction coefficients, ε
d1 and ε
d2, of said dye at said wavelengths, Γ
1 and Γ
2, and said ratio, R(0), at said time before said predetermined initial time and said ratio, R(t), at said at least one time after said predetermined initial time according to the following formula;
##EQU14## wherein C(d,t)=said concentration of said dye at the at least one time after the predetermined initial time. - View Dependent Claims (6)
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7. Method of noninvasively measuring concentration of a dye in a circulatory system of a living organism, said method comprising the steps of:
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a) measuring an optical density of an arterial blood flowing in an artery of the living organism at a wavelength Γ
1 and at another wavelength Γ
2 and at a time before a predetermined initial time;b) injecting a dye absorbing electromagnetic radiation at at least one of said wavelengths into the circulatory system of the living organism at said predetermined initial time to form an arterial blood-dye mixture; c) measuring an optical density of said arterial blood-dye mixture flowing in said artery at said wavelength Γ
1 and at said wavelength Γ
2 and at at least one time after said predetermined initial time;d) calculating a ratio of said optical density of said arterial blood at said wavelength Γ
1 to said optical density of said arterial blood at said wavelength Γ
2 at said time before said predetermined initial time and a ratio of said optical density of said arterial blood-dye mixture at said wavelength Γ
1 to said optical density of said arterial blood-dye mixture at said wavelength Γ
2 at said at least one time after said predetermined initial time;e) measuring a hemoglobin concentration, Hb, in a blood sample from said living organism, said hemoglobin concentration being equal to a sum of an oxyhemoglobin concentration, C(O), and a reduced hemoglobin concentration, C(r); f) calculating an oxygen saturation, O2Sat(0), in said arterial blood at said time before said predetermined initial time, wherein said oxygen saturation, O2Sat(0), is equal to C(0)/{C(0)+C(r)}, from the following formula;
##EQU15## wherein R(0) is said ratio of said optical density of said arterial blood at said wavelength Γ
1 to said optical density of said arterial blood at said wavelength Γ
2 at said time before said predetermined initial time;g) calculating a concentration of said dye in said arterial blood-dye mixture in said living organism at said at least one time after said predetermined initial time from said hemoglobin concentration in said blood, Hb, as measured in step e);
from said oxygen saturation, O2Sat(0), as calculated in step f);
from extinction coefficients, ε
d1 and ε
d2, of said dye at said wavelengths, Γ
1 and Γ
2 ; and
said ratio, R(0), of said optical density of said arterial blood at said wavelength Γ
1 to said optical density of said arterial blood at said wavelength Γ
2 at said time before said predetermined initial time and said ratio, R(t), of said arterial blood-dye mixture at said wavelength Γ
1 to said optical density of said arterial blood-dye mixture at said wavelength Γ
2 at said at least one time later than said predetermined initial time according to the following formula;
##EQU16## wherein C(d,t)=said dye concentration at said at least one time t after said predetermined initial time. - View Dependent Claims (8, 9)
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10. Apparatus for noninvasively measuring concentration of a dye in a circulatory system of a living organism, said apparatus comprising:
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means for measuring an optical density of an arterial blood flowing in an artery of the living organism at a wavelength Γ
1 and at another wavelength Γ
2 at a time before a predetermined initial time and for measuring an optical density of an arterial-blood dye mixture flowing in said artery at said wavelength Γ
1 and said other wavelength Γ
2 at at least one time after said predetermined initial time;means for injecting said dye into the circulatory system of the living organism at said initial time to form said arterial blood-dye mixture, said dye having an extinction coefficient ε
1 at said wavelength Γ
1 and an extinction coefficient ε
d2 at said other wavelength Γ
2 ;means for calculating a ratio of said optical density of said arterial blood at said wavelength Γ
1 to said optical density of said arterial blood at said other wavelength Γ
2 at said time before said predetermined initial time and a ratio of said optical density of said arterial blood-dye mixture at said wavelength Γ
1 to said optical density of said arterial blood-dye mixture at said other wavelength Γ
2 at said at least one time after said predetermined initial time; andmeans for calculating a concentration of said dye in said arterial blood-dye mixture at said at least one time after said predetermined initial time from a predetermined hemoglobin concentration, Hb;
from said extinction coefficients of said dye at said wavelength Γ
1 and at said other wavelength Γ
2 ; and
from said ratio at said time before said predetermined initial time and said ratio at said at least one time after said predetermined initial time. - View Dependent Claims (11, 12, 13, 14, 15)
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16. Apparatus for noninvasively measuring concentration of a dye in a circulatory system of a living organism, said apparatus comprising:
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means for measuring an optical density of an arterial blood flowing in an artery of the living organism at a wavelength Γ
1 and at another wavelength Γ
2 at a time before a predetermined initial time and for measuring an optical density of an arterial-blood dye mixture flowing in said artery at said wavelength Γ
1 and said other wavelength Γ
2 at at least one time after said predetermined initial time;means for injecting said dye into the circulatory system of the living organism at said initial time to form said arterial blood-dye mixture, said dye having an extinction coefficient ε
1 at said wavelength Γ
1 and an extinction coefficient ε
d2 at said other wavelength Γ
2 ;means for calculating a ratio of said optical density of said arterial blood at said wavelength Γ
1 to said optical density of said arterial blood at said other wavelength Γ
2 at said time before said predetermined initial time and a ratio of said optical density of said arterial blood-dye mixture at said wavelength Γ
1 to said optical density of said arterial blood-dye mixture at said other wavelength Γ
2 at said at least one time after said predetermined initial time;means for calculating an oxyhemoglobin concentration, C(O), and a reduced hemoglobin concentration, C(r), in said arterial blood at said time before said initial predetermined time according to the following formulae;
##EQU17## wherein ε
ri =an extinction coefficient of reduced hemoglobin at said wavelength Γ
i where i=1 or 2,ε
oi =an extinction coefficient of oxyhemoglobin at said wavelength Γ
i where i=1 or 2, andmeans for calculating an oxygen saturation, O2Sat(0), in said arterial blood at said one time before said predetermined initial time, wherein said oxygen saturation, O2Sat(0) is equal to C(O)/{C(O)+C(r)}; and means for calculating a concentration of said dye in said arterial blood-dye mixture at said at least one time after said predetermined initial time from a predetermined hemoglobin concentration, Hb;
said oxygen saturation, O2Sat(0);
extinction coefficients, ε
d1 and ε
d2, of said dye at said wavelengths, Γ
1 and Γ
2, and said ratio, R(O), at said time before said predetermined initial time and said ratio, R(t), at said at least one time after said predetermined initial time according to the following formula;
##EQU18## wherein C(d,t)=said concentration of said dye at the at least one time t after said predetermined initial time. - View Dependent Claims (17, 18)
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Specification