Process for determining a patient's circulatory fill status
First Claim
1. A process for determining a specific species of patient'"'"'s circulatory fill status-related parameters by calculating cardiac output according to the standard Stewart-Hamilton formula adapted for thermo-dilution measurement comprising the steps of:
- (a) placing a measurement device in the patient'"'"'s artery;
(b) injecting over a period of time an injectable comprising a cold solution into the patient'"'"'s circulatory system;
(c) recording an arterial thermo-dilution curve TD with said measurement device and calculating an appearance time AT from said arterial thermo-dilution curve; and
(d) deriving a thermo-dilution measurement curve from said injected injectate according to equation (I) to determine a value for GEDVAT TDart which reflects a sum of heart ventricle volumes without lung volume;
space="preserve" listing-type="equation">GEDV.sub.AT TDart =a×
AT-VOL.sub.TDart +b (I)
space="preserve" listing-type="equation">where AT-VOL.sub.TDar t =C. O..sub.TDart ×
AT.sub.TDartand GEDVAT TDart =global end-diastolic volume of the heartC. O.TDart =cardiac outputATTDart =appearance timea,b =species specific characteristics determined by comparing the value of GEDV determined by another process with the value of VOLTDart for the specific species of patient.
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Accused Products
Abstract
A process and a device for determining a patient'"'"'s circulatory fill status, particularly the global end-diastolic volume of the heart (GEDV), intrathoracic blood volume (ITBV), pulmonary blood volume (PBV), extravascular lung water volume (EVLW), and/or global cardiac function index (CFI) by means of thermo-dilution; with this process intrathoracic thermo-volume (ITTV) and pulmonary thermo-volume (PTV), for example, are obtained and the global end-diastolic volume of the heart (GEDV) is determined from the equation
GEDV=ITTV-PTV.
The other volumes can be calculated by means of this parameter, which is specific for the fill status of the heart, as well as other species-specific characteristics (a, a'"'"', b, b'"'"').
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Citations
28 Claims
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1. A process for determining a specific species of patient'"'"'s circulatory fill status-related parameters by calculating cardiac output according to the standard Stewart-Hamilton formula adapted for thermo-dilution measurement comprising the steps of:
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(a) placing a measurement device in the patient'"'"'s artery; (b) injecting over a period of time an injectable comprising a cold solution into the patient'"'"'s circulatory system; (c) recording an arterial thermo-dilution curve TD with said measurement device and calculating an appearance time AT from said arterial thermo-dilution curve; and (d) deriving a thermo-dilution measurement curve from said injected injectate according to equation (I) to determine a value for GEDVAT TDart which reflects a sum of heart ventricle volumes without lung volume;
space="preserve" listing-type="equation">GEDV.sub.AT TDart =a×
AT-VOL.sub.TDart +b (I)
space="preserve" listing-type="equation">where AT-VOL.sub.TDar t =C. O..sub.TDart ×
AT.sub.TDartand GEDVAT TDart =global end-diastolic volume of the heart C. O.TDart =cardiac output ATTDart =appearance time a,b =species specific characteristics determined by comparing the value of GEDV determined by another process with the value of VOLTDart for the specific species of patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Process for determining a patient'"'"'s circulatory fill status-related parameters using thermo-dilution measurement, including the steps of placing a measurement device in and injecting a cold solution into a patient'"'"'s circulatory system, deriving a value of a parameter ITTVTDart which reflects intrathoracic thermo-volume and a value of a parameter PTVTDart which reflects pulmonary thermo-volume from an arterial thermo-dilution measurement curve of the cold solution injected into the patient'"'"'s circulatory system according to the equations:
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space="preserve" listing-type="equation">ITTV.sub.TDart =C. O..sub.TDart [*]×
MTT.sub.TDart
space="preserve" listing-type="equation">PTV.sub.TDart =C. O..sub.TDart [*]×
DST.sub.TDartwhere C. O.TDart is cardiac output determined according to the thermodilution adapted standard Stewart-Hamilton formula ##EQU2## and VI =volume of injection TB =blood temperature TI =temperature of injected substance K=correction factor for specific weight and specific heat of the injected substance and of the blood T=blood temperature t=time; MTTTDart is mean transit time, and DSTTDart is exponential decay time; and determining a value of a parameter GEDVAT TDart which reflects a sum of heart ventricle volumes without lung volume by subtraction according to the equation
space="preserve" listing-type="equation">GEDV.sub.AT TDart =C. O..sub.TDart -PTV.sub.TDdart. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. Device for determining a patient'"'"'s circulatory fill status-related parameters comprising a thermo-dilution measurement arrangement having a thermo-dilution injector fluidically and electronically connected through a temperature sensor and a control and analysis unit to a pulmonary artery catheter and a femoral artery measuring device, wherein output values from the temperature sensor, the catheter and measuring device are directed to the control and analysis unit to generate intrathoracic thermo-volume values (ITTVTDart) and pulmonary thermo-volume values (PTVTDart) according to the equations:
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space="preserve" listing-type="equation">ITTV.sub.TDdart =C. O..sub.Tdart *MTT.sub.TDart
space="preserve" listing-type="equation">PTV.sub.TDdart =C. O..sub.TDart *DST.sub.TDartwhere C. O.TDart is cardiac output determined by the control and analysis unit according to the thermo-dilution adapted standard Stewart-Hamilton formula ##EQU3## and VI =volume of injection TB =blood temperature TI =temperature of injected substance K=correction factor for specific weight and specific heat of the injected substance and of the blood T=blood temperature =time; MTTTDart is mean transit time, and DSTTDart is exponential decay time; and wherein the analysis unit has a difference processor which receives the generated ITTVTDart and PTVTDart values as inputs and which produces an output value GEDVTDart corresponding to a global end-diastolic volume of the heart which reflects the sum of the ventricle volumes without the lung volume. - View Dependent Claims (20)
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21. Device for determining a patient'"'"'s circulatory fill status-related parameters comprising a thermo-dilution measurement arrangement having a thermo-dilution injector fluidically and electronically connected through a temperature sensor to a pulmonary artery catheter and a femoral artery measuring device and a control and analysis device wherein output values from the temperature sensor, the catheter and measuring device generate an appearance time ATTDart and a cardiac output C. O.TDart from a thermo-dilution curve of thermo-dilution measurements;
- wherein lists of values of species-specific characteristics a, b are stored in the analysis device; and
wherein the analysis device has a computation element which multiplies the cardiac output C. O.TDart by the appearance time ATTDart to obtain a first product, multiplies the first product by a value of species-specific characteristic a from those stored in the analysis device to obtain a second product, adds a value of species-specific characteristic b from those stored in the analysis device to the second product to obtain a resultant, and outputs the resultant as a global end-diastolic volume of the heart GEDVTDart which reflects the sum of the ventricle volumes without the lung volume. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
- wherein lists of values of species-specific characteristics a, b are stored in the analysis device; and
Specification