Dilution apparatus, method and computer program
View Patent ↗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.
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) using a degree of asymmetry of the shape of the dilution curve,
said device further configured to determine 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).
2. The apparatus according to claim 1 , wherein the apparatus is configured to determine the degree of asymmetry of the shape of the dilution curve by determining the ratio (SR) between the slopes of the dilution curve occurring in both inflection points (t u , t d ) thereof.
3. The apparatus according to claim 2 , wherein the apparatus is configured to determine the degree of asymmetry of the shape of the dilution curve by calculating the equations
α:
=
GEDV
ITTV
;
SR:
=
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c
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ⅆ
t
(
t
d
)
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t
(
t
u
)
=
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α
1
-
2
α
ⅇ
α
1
-
2
α
ln
(
1
-
α
α
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2
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1
-
α
1
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2
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1
-
α
1
-
2
α
ln
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1
-
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α
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2
.
4. 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 thereto volume (ITTV) using the degree of asymmetry of the shape of the dilution curve, and
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).
5. The non-transitory computer readable medium of claim 4 , wherein the degree of asymmetry of the shape of the dilution curve is determined based at least in part on the ratio (SR) between the slopes of the dilution curve occurring in both inflection points (t u , t d ) thereof.
6. The non-transitory computer readable medium of claim 5 , wherein the degree of asymmetry of the shape of the dilution curve is determined based at least in part on calculating the equations:
α
:
=
GEDV
ITTV
;
SR
:
=
ⅆ
c
/
ⅆ
t
(
t
d
)
ⅆ
c
/
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t
(
t
u
)
=
-
α
1
-
2
α
ⅇ
α
1
-
2
α
ln
(
1
-
α
α
)
2
+
1
-
α
1
-
2
α
ⅇ
1
-
α
1
-
2
α
ln
(
1
-
α
α
)
2
.
7. A computer-implemented method for determining a patient's circulatory fill status, the method comprising:
running a program on a computer, said program including instructions adapted to carry out the steps of:
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, and
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).