US2013109983A1PendingUtilityA1
Dilution apparatus, method and computer program
Assignee: EDWARDS LIFESCIENCES IPRM AGPriority: Dec 13, 2005Filed: Dec 20, 2012Published: May 2, 2013
Est. expiryDec 13, 2025(expired)· nominal 20-yr term from priority
A61B 5/028A61B 5/7239A61B 5/7225A61B 5/7278A61B 5/0275A61B 5/029A61B 5/0295
45
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Claims
Abstract
An apparatus for determining a patient's circulatory fill status is adapted to provide a dilution curve and is capable to derive the ratio between the patient's global end-diastolic volume GEDV and the patient's intra thoracic thermo volume ITTV from the dilution curve. Further, a computer program for determining a patient's circulatory fill status has instructions adapted to carry out the steps of generating the dilution curve on basis of provided measurement data of dilution versus time, deriving the ratio between the patient's global end-diastolic volume GEDV and the patient's intra thoracic thermo volume ITTV from the dilution curve, and determining the patient's circulatory fill status on basis of the ratio between the patient's global end-diastolic volume GEDV and the patient's intra thoracic thermo volume ITTV, when the computer program is run on a computer. A method is also provided.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . An apparatus for determining a patient's circulatory fill status comprising:
a device configured to provide a dilution curve and configured to derive a ratio between a patient's global end-diastolic volume (GEDV) and a patient's intra thoracic thermo volume (ITTV), wherein the device is configured to determine a ratio between the patient's GEDV and ITTV as a function of a ratio between a median transit time (MDT) and a mean transit time (MTT), wherein the median transit time (MDT) is defined as being the point of time on which half of the dilution curve area is reached and the mean transit time (MTT) is defined as being the point of time on which a center of mass of the dilution curve area is located, and wherein the apparatus is capable of deriving the ratio between the median transit time (MDT) and the mean transit time (MTT) from the dilution curve.
2 . The apparatus of claim 1 , wherein the apparatus is configured to determine a linear relationship between the ratio between the patient's global end-diastolic volume (GEDV) and the patient's intra thoracic thermo volume (ITTV), and the ratio between the median transit time (MDT) and the mean transit time (MTT).
3 . The apparatus of claim 2 , wherein the apparatus is configured to calculate the equation
M
D
T
M
T
T
=
a
+
b
·
G
E
D
V
I
T
T
V
,
wherein parameters a and b are set to be
a ≈ ln 2 b≈ 1−ln 2.
4 . The apparatus of claim 2 , wherein the apparatus is configured to calculate the equation
M
D
T
M
T
T
=
a
+
b
·
G
E
D
V
I
T
T
V
,
wherein parameters a and b are set to be
a≈ 0.686 and b≈ 0.377.
5 . An apparatus comprising a device configured to make use of the shape of the dilution curve for determining the distribution of the patient's heart volumes by determining a peak shape (PS) of the dilution curve for estimating the shape of the dilution curve, wherein the peak shape (PS) is defined as being the ratio between the minimum curvation radius (k min ) of the dilution curve and the peak height (c max ) of the dilution curve, wherein the curvation radius (k) of the dilution curve is defined as being
k
=
(
1
+
(
c
t
)
2
)
3
2
2
c
t
2
6 . A non-transitory computer readable medium having embodied thereon a program for determining a patient's fill status, which when executed by a computer, causes the computer to execute a method comprising:
generating a dilution curve based at least in part on provided measurement data of dilution versus time, determining a degree of asymmetry of the shape of the dilution curve, determining a ratio between the patient's global end-diastolic volume (GEDV) and the patient's intra thoracic thermo volume (ITTV) using the degree of asymmetry of the shape of the dilution curve, determining the patient's circulatory fill status based at least in part on the ratio between the patient's global end-diastolic volume (GEDV) and the patient's intra thoracic thermo volume (ITTV), determining the median transit time (MDT) being defined as the point of time on which half of the dilution curve area is reached, and the mean transit time (MTT) being defined as the point of time on which the center of mass of the dilution curve area is located, determining the ratio between the median transit time (MDT) and the mean transit time (MTT), and determining the ratio between the patient's global end-diastolic volume (GEDV) and the patient's intra thoracic thermo volume (ITTV) using the ratio between the median transit time (MDT) and the mean transit time (MTT).
7 . The non-transitory computer readable medium of claim 6 , wherein the ratio between the patient's global end-diastolic volume (GEDV) and the patient's intra thoracic thermo volume (ITTV) is determined based at least in part on a linear relationship between the ratio between the patient's global end-diastolic volume (GEDV) and the patient's intra thoracic thermo volume (ITTV), and the ratio between the median transit time (MDT) and the mean transit time (MTT).
8 . The non-transitory computer readable medium of claim 7 , calculates the equation
M
D
T
M
T
T
=
a
+
b
·
G
E
D
V
I
T
T
V
,
wherein parameters a and b are set to be
a ≈ ln 2 b≈ 1−ln 2.
9 . The non-transitory computer readable medium of claim 7 , calculates the equation
M
D
T
M
T
T
=
a
+
b
·
G
E
D
V
I
T
T
V
,
wherein parameters a and b are set to be
a≈ 0.686 and b≈ 0.377.
10 . A non-transitory computer readable medium having embodied thereon a program for determining a distribution of patient's heart volumes which when executed by a computer, causes the computer to execute a method comprising
determining a shape of a dilution curve; and determining a peak shape (PS) of the dilution curve for estimating the shape of the dilution curve, wherein the peak shape (PS) is defined as being the ratio between the minimum curvation radius (k min ) of the dilution curve and the peak height (c max ) of the dilution curve, wherein the curvation radius (k) of the dilution curve is defined as being
k
=
(
1
+
(
c
t
)
2
)
3
2
2
c
/
t
2
11 . A computer implemented method for analyzing heart volumes comprising:
determining a distribution of the patient's heart volumes as a function of a shape of a dilution curve.Join the waitlist — get patent alerts
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