US 12,029,555 B2Granted

Sensor and apparatus for determining at least one parameter of blood circulating in an extracorporeal blood circuit

AssigneeGambro Lundia AB

InventorsPaolo Rovatti, Enrico Ravagli, Stefano Severi

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Abstract

An apparatus for extracorporeal treatment of blood (1) comprising a treatment unit (2), a blood withdrawal line (6), a blood return line (7), a preparation line (19) and a spent dialysate line (13); a non-invasive blood volume sensor (50) for determining an additional property of blood is active on a tube segment (61) of the blood withdrawal line or of the blood return line; the sensor includes one source (53) for directing a signal towards the blood, a plurality of detectors (57) for receiving the signal, and a controller (65) receiving the output signals from the detectors (57) and determining a blood volume variation and a value of sodium concentration in the blood (Napl) both based on the output signals. A process of determining at least one parameter and on property of blood circulating an extracorporeal blood circuit is also disclosed.

Claims30

Dependent claims

A non-invasive blood volume sensor for determining at least one property of blood flowing in an extracorporeal segment of an extracorporeal blood treatment apparatus comprising:

at least one source for directing a signal towards the blood along an emission axis;
a plurality of detectors configured to receive the signal emitted by the at least one source after the signal at least partially passes through the blood flowing in the extracorporeal segment, and to emit respective output signals related to the received signal;
and
a controller configured to receive the respective output signals from the plurality of detectors and to determine a value of the at least one property of the blood based on the output signals, wherein the property of the blood is one of a blood volume variation, a hemoglobin concentration change, or a parameter related to the blood volume variation or the hemoglobin concentration;
wherein the controller is further configured to use a state-space mathematical model for determining the value of the at least one property of the blood and/or an auxiliary blood parameter, wherein the state-space mathematical model includes the following equations:
Δ
⁢
⁢
RB
.
⁢
V
⁡
(
t
)
=
0
N
⁢
⁢
a
P
⁢
l
.
⁡
(
t
)
=
Na
I
⁢
n
⁡
(
t
)
-
Na
P
⁢
l
⁡
(
t
)
τ
Diff
wherein
Δ{dot over (R)}BV(t) is a differential relative blood volume,
N{dot over (a)} p1 (t) is a differential plasma sodium concentration in the extracorporeal segment at instant t,
Napl(t) is a plasma sodium concentration in the extracorporeal segment at instant t,
NaIn(t) is an inlet dialysate sodium concentration at instant t at an inlet of a filtration unit, and
τDiff is a diffusion time;
wherein the diffusion time is approximate to a constant time, included between 1000 and 1200 seconds.

54 more elements

A non-invasive blood volume sensor for determining at least one property of blood flowing in an extracorporeal tube portion of an extracorporeal blood treatment apparatus comprising:

a housing having one portion which is counter-shaped to the extracorporeal tube portion and made of two or more pieces defining a through passage counter-shaped to the outer shape of the extracorporeal tube portion to house the tube portion inside the through passage;
at least one source for directing a signal towards the blood along an emission axis, wherein the at least one source includes a first fiber optic having one end coupled with a signal emitter and the other end fixed to the housing, the other end of the first fiber optic being placed at the counter-shaped portion and facing the extracorporeal tube portion in a coupling condition of the housing with the extracorporeal tube portion;
a plurality of detectors configured to receive the signal emitted by the at least one source after the signal at least partially passes through the blood flowing in the extracorporeal tube portion, and to emit respective output signals related to the received signal, wherein each of the plurality of detectors includes a respective end placed at the counter-shaped portion facing the tube portion in a coupling condition of the housing with the tube portion, wherein a first detector includes a second fiber optic, one end of the second fiber optic in correspondence with the extracorporeal tube portion is fixed to the housing, the other end of the second fiber optic being placed at the counter-shaped portion and facing the extracorporeal tube portion in a coupling condition of the housing with the extracorporeal tube portion, wherein a second detector includes a third fiber optic, one end of the third fiber optic being fixed to the housing, being placed at the counter-shaped portion and facing the extracorporeal tube portion in a coupling condition of the housing with the extracorporeal tube portion, the other end of the third fiber optic being coupled to a receiver;
a printed circuit board including circuitry for transimpedance amplification, wherein each of the plurality of detectors includes respective photodiode receivers connected to the printed circuit board, wherein the circuitry for transimpedance amplification is a current-to-voltage converter and amplifies a current output of the plurality of detectors, and wherein the printed circuit board includes lowpass filtering for filtering the signals exiting the circuitry for transimpedance amplification;
and
a controller configured to receive the respective output signals from the plurality of detectors and to determine a value of the at least one property of the blood based on the output signals, wherein the property of the blood is one of a blood volume variation, a hemoglobin concentration change, or a parameter related to the blood volume variation or the hemoglobin concentration.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/982,317Filed 20 Mar 2019
Priority: EP 1816297720 Mar 2018
Published: US 2021/0015990 A121 Jan 2021
Granted: 9 Jul 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification39 codes

A61B 5/14535
Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g.…: for…
A61B 5/0071
Using light, e.g. diagnosis by transillumination, diascopy, fluorescence: by measuring fluorescence emission
A61B 5/0075
Using light, e.g. diagnosis by transillumination, diascopy, fluorescence: by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy,…
A61B 5/0261
Measuring blood flow: using optical means, e.g. infrared light