U.S. patent application number 13/941696 was filed with the patent office on 2013-11-14 for blood reservoir with ultrasonic volume sensor.
The applicant listed for this patent is Sorin Group Italia S.r.l.. Invention is credited to Ivo Panzani, Ivan Rossi.
Application Number | 20130303965 13/941696 |
Document ID | / |
Family ID | 44788748 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130303965 |
Kind Code |
A1 |
Rossi; Ivan ; et
al. |
November 14, 2013 |
BLOOD RESERVOIR WITH ULTRASONIC VOLUME SENSOR
Abstract
A perfusion system that is easy to set-up, use and monitor
during a bypass procedure includes at least some disposable
components configured to communicate parameters to the perfusion
system. An ultrasonic blood level sensor can be used to monitor a
blood level or volume within a blood reservoir. The blood level
sensor may be utilized in an integrated perfusion system in which
the disposable components are configured, as noted above, to
communicate with the perfusion system.
Inventors: |
Rossi; Ivan; (Poggio Rusco,
IT) ; Panzani; Ivo; (Mirandola (MO), IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sorin Group Italia S.r.l. |
Milano |
|
IT |
|
|
Family ID: |
44788748 |
Appl. No.: |
13/941696 |
Filed: |
July 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13085829 |
Apr 13, 2011 |
8506513 |
|
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13941696 |
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12763559 |
Apr 20, 2010 |
8500673 |
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13085829 |
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Current U.S.
Class: |
604/6.15 ;
604/404 |
Current CPC
Class: |
A61M 1/36 20130101; A61M
2205/3592 20130101; A61M 1/3627 20130101; A61M 2205/3375 20130101;
A61M 2205/6054 20130101; A61M 1/3624 20130101; A61J 1/18 20130101;
A61M 2205/6018 20130101; A61M 2205/3569 20130101; A61M 2205/3389
20130101; A61M 1/3667 20140204; A61M 1/3666 20130101 |
Class at
Publication: |
604/6.15 ;
604/404 |
International
Class: |
A61J 1/18 20060101
A61J001/18; A61M 1/36 20060101 A61M001/36 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 20, 2010 |
EP |
10160436.1 |
Apr 12, 2011 |
EP |
11162020.9 |
Claims
1. A perfusion system comprising: a heart lung machine; a blood
reservoir adapted to hold a fluid, the blood reservoir having a
capacity determined by a geometric configuration, wherein the blood
reservoir includes an information device for communicating
information about the geometric configuration of the blood
reservoir; an ultrasonic sensor coupled to the blood reservoir and
configured to determine a fluid level within the blood reservoir; a
receiver configured to communicate with the information device to
receive the information about the geometric configuration of the
blood reservoir; a controller coupled to the heart lung machine and
to the receiver, the controller configured to receive the fluid
level from the ultrasonic sensor and to receive the information
about the geometric configuration of the blood reservoir from the
receiver, the controller configured to calculate a blood volume
contained within the blood reservoir based on the fluid level and
the geometric configuration; and a display coupled to the heart
lung machine, the display configured to display the calculated
blood volume; wherein the heart lung machine is configured to
adjust an operating parameter based on the calculated blood
volume.
2. The perfusion system of claim 1, wherein the ultrasonic sensor
comprises a spaced apart pair of ultrasonic transducers coupled to
a wall of the blood reservoir.
3. The perfusion system of claim 2, wherein the pair of ultrasonic
transducers comprises a first ultrasonic transducer configured to
emit a single pulse that generates a flexural wave in the wall and
a second ultrasonic transducer configured to receive the flexural
wave.
4. The perfusion system of claim 3, wherein the controller is
configured to determine the fluid level within the blood reservoir
based on phase delays in the flexural wave.
5. The perfusion system of claim 1, wherein the ultrasonic sensor
comprises a piezoelectric element disposed within a housing.
6. The perfusion system of claim 5, wherein the ultrasonic sensor
is removably secured to the blood reservoir.
7. The perfusion system of claim 6, wherein the ultrasonic sensor
may be adhesively secured to the blood reservoir.
8. The perfusion system of claim 7, wherein the ultrasonic further
comprises double faced tape, with one adhesive side secured to the
housing and an opposing adhesive side secured to the blood
reservoir.
9. The perfusion system of claim 1, wherein the ultrasonic sensor
is molded into a wall of the blood reservoir.
10. The perfusion system of claim 1, wherein the controller is
further configured to operate the heart lung machine in accordance
with the calculated blood volume in the blood reservoir.
11. The perfusion system of claim 1, further comprising a polymeric
tube disposed within the blood reservoir, with the ultrasonic
sensor disposed proximate an upper end of the polymeric tube.
12. A blood reservoir system comprising: a blood reservoir
configured to hold a blood volume; an ultrasonic sensor securable
to the blood reservoir, the ultrasonic sensor configured to provide
an electrical signal indicative of a level of blood within the
blood reservoir; an information tag securable to the blood
reservoir, the information tag configured to store information
describing the geometric configuration of the blood reservoir; a
controller configured to receive the electrical signal, indicative
of the level of blood within the reservoir, from the ultrasonic
sensor, and to receive the information describing the geometric
configuration of the blood reservoir from the information tag, the
controller configured to calculate and to output a signal
indicative of a blood volume within the blood reservoir; and a
display coupled to the controller, the display configured to
display the calculated blood volume.
13. The blood reservoir system of claim 12, wherein the ultrasonic
sensor is structurally integrated into the blood reservoir.
14. The blood reservoir system of claim 13, wherein the ultrasonic
sensor is integrated into a cover portion of the blood
reservoir.
15. The blood reservoir system of claim 12, wherein the ultrasonic
sensor is structurally separate from the blood reservoir and
further wherein the ultrasonic sensor is configured for removably
coupling with the blood reservoir.
16. The blood reservoir system of claim 12, further comprising a
guide tube disposed within the blood reservoir and coupled to a top
surface of the reservoir and further wherein the ultrasonic sensor
is secured to the reservoir such that the sensor is in
communication with an interior lumen of the guide tube.
17. The blood reservoir system of claim 12, wherein the blood
reservoir comprises a soft shell reservoir.
18. The blood reservoir system of claim 12, wherein the blood
reservoir comprises a hard shell reservoir.
19. The blood reservoir system of claim 12, wherein the ultrasonic
sensor is configured to communicate wirelessly with the
controller.
20. The blood reservoir system of claim 15, wherein the ultrasonic
sensor includes an active RFID tag that communicates with the
controller.
Description
RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 13/085,829, filed Apr. 13, 2011, which is a
continuation-in-part of U.S. application Ser. No. 12/763,559, filed
Apr. 20, 2010, entitled "Blood Reservoir with Level Sensor"; and
which claims priority to European Application No. 11162020.9, filed
Apr. 12, 2011 and to European Application No. 10160436.1, filed
Apr. 20, 2010, all of which are hereby incorporated by
reference.
TECHNICAL FIELD
[0002] The disclosure relates generally to perfusion systems and
more particularly to a blood reservoir having a level sensor.
BACKGROUND
[0003] Perfusion entails encouraging physiological solutions such
as blood through the vessels of the body or a portion of a body of
a human or animal. Illustrative examples of situations that may
employ perfusion include extracorporeal circulation during
cardiopulmonary bypass surgery as well as other surgeries. In some
instances, perfusion may be useful in providing extracorporeal
circulation during various therapeutic treatments. Perfusion may be
useful in maintaining the viability of body parts such as specific
organs or limbs, either while the particular body part remains
within the body, or while the body part is exterior to the body
such as for transplantation or if the body part has been
temporarily removed to provide access to other body structures. In
some instances, perfusion may be used for a short period of time,
typically defined as less than about six hours. In some cases,
perfusion may be useful for extended periods of time that are
greater than about six hours.
[0004] In some instances, blood perfusion systems include one or
more pumps in an extracorporeal circuit that is interconnected with
the vascular system of a patient. Cardiopulmonary bypass (CPB)
surgery typically requires a perfusion system that allows for the
temporary cessation of the heart by replacing the function of the
heart and lungs. This creates a still operating field and allows
for the surgical correction of vascular stenosis, valvular
disorders, and congenital heart and great vessel defects. In
perfusion systems used for cardiopulmonary bypass surgery, an
extracorporeal blood circuit is established that includes at least
one pump and an oxygenation device to replace the functions of the
heart and lungs.
[0005] More specifically, in cardiopulmonary bypass procedures,
oxygen-poor blood (i.e., venous blood) is gravity-drained or vacuum
suctioned from a large vein entering the heart or other veins
(e.g., femoral) in the body and is transferred through a venous
line in the extracorporeal circuit. The venous blood is pumped to
an oxygenator that provides for oxygen transfer to the blood.
Oxygen may be introduced into the blood by transfer across a
membrane or, less frequently, by bubbling oxygen through the blood.
Concurrently, carbon dioxide is removed across the membrane. The
oxygenated blood is then returned through an arterial line to the
aorta, femoral, or other main artery.
[0006] A perfusion system typically includes various fluid
circuitry and components that are configured by medical personnel
prior to the bypass procedure. This can be a time consuming process
and may require significant manual input of information relating to
various components of the system.
SUMMARY
[0007] Example 1 is a perfusion system including a heart lung
machine and a blood reservoir that is adapted to hold a fluid. The
blood reservoir has a volume that is determined by a geometric
configuration and may include a communication device for
communicating the geometric configuration to the heart lung
machine. An ultrasonic blood level sensor is coupled to the blood
reservoir and is configured to determine a fluid level within the
blood reservoir. A controller is coupled to the heart lung machine
and is configured to receive the fluid level and calculate a blood
volume contained within the blood reservoir, based on the fluid
level and the geometric configuration. The heart lung machine may
be configured to adjust an operating parameter based on the
calculated blood volume.
[0008] In Example 2, the perfusion system of Example 1 in which the
ultrasonic blood level sensor includes a spaced apart pair of
ultrasonic transducers coupled to a wall of the blood vessel.
[0009] In Example 3, the perfusion system of Example 2 in which the
pair of ultrasonic transducers includes a first ultrasonic
transducer configured to emit a single pulse that generates a
flexural wave in the wall and a second ultrasonic transducer
configured to receive the flexural wave.
[0010] In Example 4, the perfusion system of Example 3 in which the
controller is configured to determine the fluid level within the
blood reservoir based on phase delays in the flexural wave.
[0011] In Example 5, the perfusion system of Example 1 in which the
ultrasonic blood level sensor includes a piezoelectric element
disposed within a housing.
[0012] In Example 6, the perfusion system of Example 5 in which the
ultrasonic blood level sensor is removably secured to the blood
reservoir.
[0013] In Example 7, the perfusion system of Example 6 in which the
ultrasonic blood level sensor may be adhesively secured to the
blood reservoir.
[0014] In Example 8, the perfusion system of Example 7 in which the
ultrasonic further includes double faced tape, with one adhesive
side secured to the housing and an opposing adhesive side secured
to the blood reservoir.
[0015] In Example 9, the perfusion system of any of Examples 1-8 in
which the ultrasonic sensor is molded into a wall of the blood
reservoir.
[0016] In Example 10, the perfusion system of any of Examples 1-9
in which the controller is further configured to operate the heart
lung machine in accordance with the calculated blood volume in the
blood reservoir.
[0017] In Example 11, the perfusion system of Example 1, further
including a polymeric tube disposed within the blood reservoir,
with the ultrasonic blood level sensor disposed proximate an upper
end of the polymeric tube.
[0018] Example 12 is a blood reservoir system including a blood
reservoir that includes a wall and that is configured to hold a
blood volume. An ultrasonic blood level sensor is securable to the
blood reservoir and is configured to provide an electrical signal
indicative to a level of blood within the blood reservoir. A
controller is configured to receive the electrical signal from the
ultrasonic blood level sensor and output a signal indicative of a
blood volume within the blood reservoir.
[0019] In Example 13, the blood reservoir system of Example 12 in
which the ultrasonic sensor is structurally integrated into the
blood reservoir.
[0020] In Example 14, the blood reservoir system of Example 12 in
which the ultrasonic sensor is integrated into a cover portion of
the blood reservoir.
[0021] In Example 15, the blood reservoir system of any of Examples
12-14, in which the ultrasonic sensor is structurally separate from
the blood reservoir and further wherein the ultrasonic sensor is
configured for removably coupling with the blood reservoir.
[0022] In Example 16, the blood reservoir system of any of Examples
12-15 further comprising a guide tube disposed within the blood
reservoir and coupled to a top surface of the reservoir and further
wherein the ultrasonic sensor is secured to the reservoir such that
the sensor is in communication with an interior lumen of the guide
tube.
[0023] In Example 17, the blood reservoir system of any of Examples
12-16, in which the blood reservoir comprises a soft shell
reservoir.
[0024] In Example 18, the blood reservoir system of any of Examples
12-17, wherein the blood reservoir comprises a hard shell
reservoir.
[0025] In Example 19, the blood reservoir system of any of Examples
12-18, in which the ultrasonic sensor is configured to communicate
wirelessly with the controller.
[0026] In Example 20, the blood reservoir system of Example 15, in
which the ultrasonic sensor includes an active RFID tag that
communicates with an RF sensor operably connected to the
controller.
[0027] While various embodiments are shown and described herein
with reference to a blood level sensor, many of these embodiments
may also be described with reference to a blood volume sensor. As
described in further detail below, where the geometry of the blood
reservoir is known, it is possible to provide information from the
sensor as either a level or a volume, as the volume of fluid in the
reservoir may be readily calculated from the detected or sensed
blood level, based on the known geometry of the reservoir.
[0028] While multiple embodiments are disclosed, still other
embodiments of the present invention will become apparent to those
skilled in the art from the following detailed description, which
shows and describes illustrative embodiments of the invention.
Accordingly, the drawings and detailed description are to be
regarded as illustrative in nature and not restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a schematic illustration of an integrated
perfusion system in accordance with an embodiment of the
invention.
[0030] FIG. 2 is a flow diagram illustrating a method that can be
carried out by the integrated perfusion system of FIG. 1.
[0031] FIG. 3 is a flow diagram illustrating a method that can be
carried out by the integrated perfusion system of FIG. 1.
[0032] FIG. 4 is a schematic illustration of a heart lung machine
pack that may be utilized with the integrated perfusion system of
FIG. 1.
[0033] FIG. 5 is a schematic illustration of a perfusion system in
accordance with an embodiment of the invention.
[0034] FIG. 6 is an illustration of a blood level sensor that may
be utilized with the perfusion system of FIG. 5.
[0035] FIG. 7 is an illustration of a blood level sensor
incorporated into a label that may be utilized with the perfusion
system of FIG. 5.
[0036] FIG. 8 is an illustration of a blood reservoir including a
blood level sensor in accordance with an embodiment of the
invention.
[0037] FIG. 9 is an illustration of a hard shell blood reservoir
including a blood level sensor in accordance with an embodiment of
the invention.
[0038] FIG. 10 is an illustration of a soft shell blood reservoir
including a blood level sensor in accordance with an embodiment of
the invention.
[0039] FIG. 11 is a flow diagram illustrating a method that can be
carried out using the perfusion system of FIG. 5.
[0040] FIGS. 12-15 are illustrations blood reservoirs including a
blood level sensor in accordance with various embodiments of the
invention.
[0041] FIG. 16 is an illustration of the blood level sensor of FIG.
15.
[0042] FIG. 17 is a schematic view of a blood reservoir including
an ultrasonic sensor and a guide tube, according to exemplary
embodiments of the invention.
DETAILED DESCRIPTION
[0043] The disclosure relates to a perfusion system that is easy to
set-up, use and monitor during a bypass procedure. In some
embodiments, the disclosure relates to a perfusion system in which
at least some of the disposable components used with the perfusion
system are encoded with set-up and/or operational parameters. In
some embodiments, the disclosure relates to a blood sensor that can
be used to monitor a blood level or volume within a blood
reservoir. The blood sensor may be utilized in an integrated
perfusion system in which the disposable components are configured,
as noted above, to communicate with the perfusion system. In some
embodiments, the blood sensor may be utilized with a perfusion
system lacking communication with disposables. According to various
embodiments, the blood sensor may be considered as either a blood
level sensor or a blood volume sensor, as the blood volume is
readily ascertainable from the sensed blood level, based on the
known geometric configuration of the blood reservoir.
[0044] FIG. 1 is a schematic illustration of an integrated
perfusion system 10 including a heart lung machine (HLM) 12 and a
disposable element 14. While only a single disposable element 14 is
shown for ease of illustration, in many embodiments a plurality of
different disposable elements 14 may be utilized in combination
with the HLM 12. Each of the HLM 12 and the disposable element 14
will be described in greater detail subsequently. The HLM 12
includes a number of different components. It is to be understood
that the particular components illustrated herein as being part of
the HLM 12 is merely an example, as the HLM 12 may include other
components or different numbers of components.
[0045] In the illustrated embodiment, the HLM 12 includes three
pump modules 16, but may include as few as two pump modules 16 or
as many as six or seven pump modules 16. In some embodiments, the
pump modules 16 may be roller or peristaltic pumps. In some
embodiments, one or more of the pump modules 16 may be centrifugal
pumps. Each of the pump modules 16 may be used to provide fluid or
gas for delivery to or removal from the heart chambers and/or
surgical field. In an illustrative but non-limiting example, one
pump module 16 draws blood from the heart, another provides
surgical suction and a third provides cardioplegia fluid (high
potassium solution to arrest the heart). Additional pump modules 16
(not shown) may be added to provide additional fluid transfer.
[0046] Each pump module 16 includes a control unit 18. In some
embodiments, each control unit 18 may be configured to operate and
monitor the operation of the particular pump module 16 to which it
is attached or otherwise connected to. In some embodiments, each
control unit 18 may include one or more input devices (not
illustrated) such as switches, knobs, buttons, touch screens and
the like so that the perfusionist may adjust the operation of the
particular pump module 16. Each pump module 16 may include an
alphanumeric display that the control unit 18 can use to display,
for example, the value of a setting, the value of a current
operating parameter, confirmation that the pump module 16 is
operating normally, and the like.
[0047] The HLM 12 includes a controller 20 that is in communication
with the control units 18 and that is configured to operate the HLM
12. In some embodiments, the controller 20 is configured to monitor
one or more sensors that may be distributed on the HLM 12 and/or
within the disposable element 14 to monitor operation of the HLM
12. Examples of such sensors (not illustrated for ease of
illustration) include but are not limited to flow meters, pressure
sensors, temperature sensors, blood gas analyzers and the like.
[0048] While the control units 18 and the controller 20 are
illustrated as distinct elements, in some embodiments it is
contemplated that these elements may be combined in a single
controller. In some embodiments, it is contemplated that the
control units 18, in combination, may be configured to operate the
HLM 12, thereby negating a need for the controller 20.
[0049] The controller 20 communicates with an input device 22 and
an output device 24. The input device 22 may be used by the
perfusionist to enter information that is not otherwise entered
into the control units 18. The output device 24 may be used by the
HLM 12 to display pertinent information to the perfusionist. In
some embodiments, the input device 22 may be a key pad, a keyboard,
a touch screen, and the like. In some embodiments, the output
device 24 may be a monitor. In some embodiments, either of the
input device 22 and/or the output device 24 may be a computer such
as a personal computer, a laptop computer, a notebook computer or a
tablet computer. In some cases, the input device 22 and the output
device 24 may be manifested in a single computer.
[0050] According to various embodiments, the HLM 12 also includes
an RF sensor 26. In some embodiments, the RF sensor 26 may be
configured to receive information from an active RFID tag placed on
the disposable element 14. In some embodiments, the RF sensor 26
may be a hand held device that is used to scan a passive RFID tag
on the disposable element 14. According to other embodiments, the
RF sensor 26 is replaced with any of a variety of known wireless
communication receivers. The disposable element 14 includes an RFID
tag 28. According to various embodiments, the disposable element 14
includes either an active RFID tag or a passive RFID tag (or both)
configured to communicate with the RF sensor 26. In other
embodiments, the RFID tag 28 is replaced with any of a variety of
known wireless communication transmitters. According to various
embodiments, the system includes one or more of the RFID
configurations disclosed in U.S. patent application Ser. No.
12/763,561, filed on Apr. 20, 2010, which is hereby incorporated by
reference in its entirety.
[0051] Passive RFID tags lack a power supply, and instead are
powered by an induced current caused by an incoming radio-frequency
scan. Because there is no onboard power supply, a passive RFID tag
is smaller and less expensive. An active RFID tag includes an
onboard power supply such as a battery. While this increases the
size and expense of the RFID tag, an advantage is that the RFID tag
can store more information and can transmit further. RFID tags,
whether active or passive, may be selected to transmit at a variety
of frequencies depending on need. Options include low frequency
(about 100 to 500 kilohertz), high frequency (about 10 to 15
megahertz), ultra high frequency (about 860 to 960 megahertz) and
microwave (about 2.45 gigahertz).
[0052] As noted above, the disposable element 14 may be considered
as generically representing one, two or a plurality of different
disposable elements that may be used in conjunction with the HLM
12. Illustrative but non-limiting examples of disposable elements
14 include tubing sets, blood reservoirs, oxygenators, heat
exchangers and arterial filters. In some embodiments, a tubing set
includes a number of different tubes, potentially of different
lengths and sizes, for providing fluid flow between components of
the HLM 12 as well as providing fluid flow between the HLM 12 and a
patient.
[0053] In some embodiments, the disposable element 14 may be a
blood reservoir such as a venous blood reservoir, a vent blood
reservoir, a cardiotomy or suction blood reservoir. In some
embodiments, the disposable element 14 may be a blood reservoir
that combines one or more of a venous blood reservoir, a vent
reservoir and/or a suction reservoir in a single structure. In some
embodiments, one or more of the aforementioned sensors may be
disposable elements that include an RFID tag 28 either to provide
information identifying the sensor or even for transmitting sensed
values to the controller 20.
[0054] The RFID tag 28 may be attached to the disposable element 14
in any appropriate manner. In some embodiments, the RFID tag 28 may
be adhesively secured to the disposable element 14. In some
embodiments, the RFID tag 28 may be molded into the disposable
element 14. In some embodiments the RFID tag 28 may be a stand
alone card, similar in size and shape to a credit card, that may
simply be packed with the disposable element 14 in such a way that
it can be removed by the user and swiped by the RF sensor 26.
However the RFID tag 28 is attached, the RFID tag 28 may be
programmed with or otherwise configured to include a wide variety
of information pertaining to the disposable element 14.
[0055] In some embodiments, the RFID tag 28 may include data or
identifying information for the disposable element 14. Illustrative
but non-limiting examples of identifying information include the
name of the particular disposable element 14, a reference code, a
serial number, a lot number, an expiration date and the like. In
some embodiments, this information may be communicated to the
controller 20 and may, for example, be used by the controller 20 to
confirm that the proper disposable elements 14 are being used for a
particular setting, patient or the like. As an example, the
controller 20 may recognize that a pediatric tubing set is being
used in combination with an adult-sized blood reservoir or other
component. As another example, the controller 20 may recognize that
an expected component is missing. There are a variety of other
potential mismatches in equipment that may be recognized by the
controller 20 as a result of the information provided by the RFID
tag 28 attached to each of the one or more disposable elements
14.
[0056] In some embodiments, the RFID tag 28 may include descriptive
or design information for the disposable element 14. Illustrative
but non-limiting examples of descriptive or design information
include specific materials, a list of components, priming volume of
a component or tubing circuit, tubing size, tubing length, minimum
and maximum working pressures, minimum and maximum working volume,
and the like. In some embodiments, this information may be
communicated to the controller 20 and may be used by the controller
20 to at least partially configure and/or operate the HLM 12. As an
example, the controller 20 may use the sizing information provided
from each of the disposable elements 14 to determine a working
blood volume for the HLM 12.
[0057] In some embodiments, the information obtained from the RFID
tag 28 may also be provided to the perfusionist. In some
embodiments, the output device 24 may be configured to provide
alphanumeric or graphical representations of the obtained
information. In some cases, the RFID tag 28 may include
instructional information that may be displayed by the output
device 24 in order to instruct the perfusionist in optimal setup
and/or operation of a particular disposable element 14. In various
embodiments, the output device 24 may be a computer such as a
personal computer, a laptop computer, a notebook computer or a
tablet computer. In some embodiments, the RFID tag 28 may include
displayable information that, for example, suggests an optimal
circuit design based upon the specific components being used, or
perhaps updated use instructions. In some embodiments, information
from the RFID tag 28 is displayed on an integrated data management
system (DMS).
[0058] In some embodiments, the RFID tag 28 may include information
that a manufacturer of the disposable element 14 wants to provide
to the user. Examples of such information may include technical
features of the disposable element 14 that have changed from a
previous version or even a previous batch. Another example includes
information that can be displayed by the output device 24 that
require the user to acknowledge receipt of the information before
the controller 20 proceeds with a particular procedure. In some
cases, the RFID tag 28 may receive error messages from the
controller 20, and the RFID tag 28 may then be returned to the
manufacturer, thereby providing the manufacturer with feedback
regarding the performance of the disposable element 14 as well as
other components.
[0059] FIG. 2 is a flow diagram illustrating a method that may be
carried out using the perfusion system 10 of FIG. 1. A disposable
element 14 having an RFID tag 28 may be attached to the HLM 12, as
generally shown at block 30. At block 32, the RFID tag 28 is read.
As noted above, the RFID tag 28 may be an active RFID tag or a
passive RFID tag. In some embodiments, the RFID tag 28 may be read
before the disposable element 14 is attached to the HLM 12. In some
embodiments, the RFID tag 28 may be read after attachment. At block
34, the HLM 12 is configured based at least in part upon
information that was read from the RFID tag 28 at block 32. In some
embodiments, the controller 20 automatically configures the HLM 12
in response to this information.
[0060] FIG. 3 is a flow diagram illustrating a method that may be
carried out using the perfusion system 10 of FIG. 1. A disposable
element 14 having an RFID tag 28 may be attached to the HLM 12, as
generally shown at block 30. At block 32, the RFID tag 28 is read.
The RFID tag 28 may be read either before or after the disposable
element 14 is attached to the HLM 12. At block 34, the HLM 12 is
configured based at least in part upon information that was read
from the RFID tag 28 at block 32. In some embodiments, the
controller 20 automatically configures the HLM 12 in response to
this information. At least some of the information read from the
RFID tag 28 may be displayed on the output device 24, as seen at
block 36.
[0061] FIG. 4 is a schematic illustration of a heart lung machine
pack 38 that may be utilized with the perfusion system 10 of FIG.
1. In some embodiments, the heart lung machine pack 38 may include
all of the disposable elements 14 that will be used together for a
particular patient and may be customized for the particular
patient. In some embodiments, the heart lung machine pack 38 may
include a housing 40 that, once filled, can be sealed up to keep
the contents clean and sterile.
[0062] In the illustrated embodiment, the heart lung machine pack
38 includes a tubing set 42 and a disposable component 44. The
tubing set 42 may include a plurality of different tubes. The
disposable component 44 may be any of the disposable components
discussed above with respect to the disposable element 14. In some
embodiments, the heart lung machine pack 38 will include a
plurality of different disposable components 44. The tubing set 42
includes a first RFID tag 46 while the disposable component 44
includes a second RFID tag 48. As discussed above, each of the
first RFID tag 46 and the second RFID tag 48 may be either active
or passive RFID tags and may include readable information
pertaining to the component to which they are attached. In some
instances, the housing 40 may include a third RFID tag 50 that, for
example, identifies the contents of the heart lung machine pack 38.
In some embodiments, the first RFID tag 46 and the second RFID tag
48 may not be included, as the third RFID tag 50 may be encoded
with all of the information for the tubing set 42 and the
disposable component 44.
[0063] FIG. 5 is a schematic illustration of a perfusion system 52.
The perfusion system 52 includes an HLM 54 that in some embodiments
may be similar in structure and operation to the HLM 12 discussed
with respect to FIG. 1. The perfusion system 52 also includes a
blood reservoir 56, a blood level/volume sensor 58 and a controller
60. The blood reservoir 56 may be a venous blood reservoir, a vent
blood reservoir, a cardiotomy or suction blood reservoir. In some
embodiments, the blood reservoir 56 may be a blood reservoir that
combines one or more of a venous blood reservoir, a vent reservoir
and/or a suction reservoir in a single structure.
[0064] The blood volume sensor 58 may be configured to continuously
monitor a variable blood level within the blood reservoir 56. The
blood volume sensor may be chosen from a variety of different
sensing technologies. In some embodiments, as will be discussed
subsequently with respect to FIGS. 12-16, the sensor 58 may be an
ultrasonic sensor in which ultrasound is used to detect the blood
level within the blood reservoir 56. In some embodiments, the
sensor 58 may be an optical sensor in which a laser beam or light
from an infrared light source is reflected by the liquid-air
interface and the reflected light beam is detected by the sensor
58. In some embodiments, the blood level/volume sensor 58 is an
optical distance sensor of the type commercially sold by Leuze
electronic GmbH located in Owen/Teck, Germany (e.g., ODSL8, ODSL
30, or ODS 96). In some embodiments, the sensor 58 may be a load
cell or scale that is configured to measure a mass of the blood
reservoir 56 and thereby determine the volume of blood therein.
[0065] In some embodiments, the blood volume sensor 58 may be a
capacitive sensor (better illustrated in subsequent Figures) that
outputs an electrical signal that is proportional to or otherwise
related to a blood level and/or volume within the blood reservoir
56. The electrical signal may be communicated in either a wired or
wireless fashion to the controller 60. While the controller 60 is
shown as a distinct element, in some embodiments the controller 60
is manifested as part of a controller (similar to the controller
20) operating the HLM 54.
[0066] In some embodiments, the blood volume sensor 58 may be
modeled after capacitive sensors (e.g., CLC or CLW series)
available commercially from Sensortechnics GmbH located in
Puchheim, Germany, which are configured to provide contact-free
measurement of continuous liquid level. The sensor available from
Sensortechnics may be disposed on an outer surface of a container
and provides an electrical signal representative of the liquid
level within the container. In some instances, the Sensortechnics
sensor may be spaced as much as about five millimeters from the
liquid within the sensor, with no more than about twenty percent
air gap between the sensor and the liquid. According to various
embodiments, the capacitive sensor 58 is molded inside the blood
reservoir 56, such that only the connector is accessible outside
the reservoir. In these embodiments, the sensor 58 is protected by
the plastic material of the blood reservoir.
[0067] In some embodiments, the sensor may undergo an initial
configuration to adapt the sensor to the particulars of the
container itself as well as the liquid within the container. In
some embodiments, the blood volume sensor 58 has a five pin
electrical connection, including a voltage source, an analog signal
out, a digital signal out, a teach-in pin and a ground. In some
embodiments, the sensor 58 is a capacitive sensor such as the
Balluff SmartLevel sensor commercially sold by Balluff GmbH located
in Neuhausen, Germany.
[0068] The controller 60 may receive an electrical signal that is
proportional to or at least related to a blood level within the
blood reservoir 56. The controller 60 may calculate a blood volume
based on this electrical signal as well as a known shape or
geometry of the blood reservoir 56. In some embodiments, the blood
reservoir 56 may include an RFID tag (not illustrated) that
provides the controller 60 with information pertaining to the known
geometry of the blood reservoir 56. According to various exemplary
embodiments, the volume of the blood reservoir is calculated
according to one or more of the techniques described in copending
U.S. patent application Ser. No. 12/763,561, filed on Apr. 20,
2010, which is hereby incorporated by reference. According to
various embodiments, the volume of the blood reservoir is
calculated by integrating the detected level of blood in the
reservoir against the known cross-sectional area of the blood
reservoir at various heights throughout the reservoir.
[0069] If the blood reservoir 56 is a hard shell blood reservoir,
the known geometry of the blood reservoir 56 may include the
cross-sectional area of the blood reservoir 56, or a width and
depth of the blood reservoir 56 as well as details on how this
cross-sectional area varies relative to height within the blood
reservoir 56. If the blood reservoir 56 is a soft shell reservoir,
the known geometry may be based at least in part upon a known
lateral expansion rate of the soft shell reservoir relative to the
blood level within the blood reservoir 56.
[0070] As can be seen in FIG. 6, the blood volume sensor 58
includes a first elongate electrode 60 and a second elongate
electrode 62. The first elongate electrode 60 and the second
elongate electrode 62 are disposed along a flexible substrate 64.
In some embodiments, the flexible substrate 64 may include an
adhesive layer that can be used to secure the sensor 58 to the
blood reservoir 56. A connector socket 66 is secured to the
flexible substrate 64 and is electrically connected to the first
elongate electrode 60 and the second elongate electrode 62 in order
to permit an electrical connection between the first and second
electrodes 60, 62 and an electrical cable (not illustrated in this
Figure). In some embodiments, rather than an elongate sensor, the
sensor 58 may include two or more distinct SMARTLEVEL.TM.
capacitive sensors such as those available commercially from
Balluff. These sensors may provide a binary, yes/no signal. By
locating several of these sensors at differing levels proximate the
blood reservoir 56, the blood level and/or volume within the blood
reservoir 56 may be determined.
[0071] In some embodiments, the sensor 58 may be attached to or
otherwise integrated into a label 68 as seen in FIG. 7. The label
68 may include various indicia 70 such as use instructions, volume
indicators and the like. In some embodiments, the label 68 may
include an adhesive side for attachment to an outer surface of the
blood reservoir 56. In some embodiments, the label 68 is oriented
on the blood reservoir such that a lower portion of the sensor 58
is aligned at or near a bottom of the blood reservoir 56.
[0072] FIG. 8 is an illustration of the blood volume sensor 58
attached to the blood reservoir 56. An electrical cable 72 provides
an electrical connection between the sensor 58 and the controller
60. The electrical cable 72 includes a plug 73 that is configured
to connect to the electrical connector 66. In some embodiments, the
plug 73 includes circuitry that converts a detected capacitance
into a voltage signal that the controller 60 can use to calculate
the blood volume. In some embodiments, the plug 73 further includes
circuitry to calculate the blood volume.
[0073] As noted above, the blood reservoir 56 may be either a hard
shell reservoir or a soft shell reservoir. FIG. 9 illustrates a
hard shell reservoir 74 bearing the blood volume sensor 58 while
FIG. 10 illustrates a soft shell reservoir 76 including the sensor
58. In either case, the reservoir may be constructed to include the
sensor 58. In some embodiments, the blood level sensor 58 may be
adhesively secured to an existing blood reservoir.
[0074] FIG. 11 is a flow diagram illustrating a method that may be
carried out using the perfusion system 52 of FIG. 5. A capacitance
between first and second electrodes may be detected, as referenced
at block 78. In some embodiments, as discussed above, the
capacitance may be converted into an electrical signal representing
the blood level by circuitry within the plug 73. In embodiments
using the CLC series Sensortechnics sensor, for example, the sensor
will output a voltage between 0.5 and 4.5 volts. Assuming the
sensor pad is appropriately located on the reservoir, this voltage
indicates a level or height of the liquid in the reservoir. At
block 80, the controller 60 may calculate a blood volume that is
based upon the detected capacitance and a known dimensions or
geometry of the blood reservoir 56. In some embodiments, the
controller 60 (or other circuitry within the HLM 54) may provide
the circuitry in the plug 73 with sufficient information (e.g.,
dimensions or geometry) regarding the blood reservoir 56 to permit
the circuitry to perform the blood volume calculation. In some
embodiments, the calculated blood volume is communicated to the HLM
54 so that it may adjust an operating parameter of the HLM 54. In
various exemplary embodiments, the HLM 54 may alter a pump speed to
either increase or decrease blood flow into or out of the blood
reservoir 56. It may be important, for example, to prevent the
blood level in the reservoir 56 from moving below a certain minimum
level or volume. Accordingly, in various embodiments, the HLM will
compare the blood level or volume to this minimum level and adjust
pump speed appropriately.
[0075] According to other embodiments, the HLM may use the blood
volume information for a variety of applications, including for
example auto-regulation of pump occlusion, auto-loading of pump
segments, conducting automatic occlusivity testing, performing
automatic priming, automatic recirculating and debubbling,
conducting automatic pressure tests, or performing automatic system
emptying.
[0076] In some embodiments, the sensor may be an ultrasonic blood
volume sensor, as illustrated in FIGS. 12 and 13. FIG. 12 is an
illustration of a blood reservoir 82 that contains a volume of
blood. The volume of blood defines an interface 84 between the
volume of blood and the air or other fluid within the blood
reservoir 82. In some embodiments, an ultrasonic transducer 86 that
is located at or near a lower surface of the blood reservoir 82 can
be used to locate the interface 84 by transmitting ultrasonic waves
88 through the fluid (e.g., blood) in the reservoir towards the
interface 84. The reflectance of the ultrasonic waves 88 depends at
least in part upon the fluid they are passing through. Thus, by
measuring the reflectance, the ultrasonic transducer 86 can
determine the distance from the interface 84 and thereby determine
the fluid level. The ultrasonic transducer may be any of a variety
of well-known and commercially available ultrasonic transducers.
The ultrasonic transducer, may for example, by any of a variety of
commercially available piezoelectric transducers or crystals.
According to various exemplary embodiments, the ultrasound
transducer is a piezoelectric transducer available from Piezo
Technologies of Indianapolis, Ind., USA. In some embodiments, the
ultrasonic transducer 160 may be an ultrasonic transducer such as
the P43-F4V-2D-1C0-360E, the P41-D4V-2D-1C0-360E, and/or the
P44-T4V-2D-001-180E ultrasonic transducers commercially available
from Pil Sensoren GmbH in Erlensee, Germany.
[0077] In various embodiments, based on the fluid level and the
known geometric configuration of the blood reservoir 82, a
controller calculates the blood volume within the blood reservoir
82. In various embodiments, for example, the blood volume is
calculated by integrating the detected blood level across the known
cross sectional area at each location within the blood reservoir
82. In some embodiments, a cable 90 transmits a signal from the
ultrasonic transducer 86 to the controller. In some embodiments,
the information is transmitted wirelessly.
[0078] FIG. 13 is similar to FIG. 12, but shows a blood reservoir
92 having a blood volume defining an interface 94. In this
embodiment, an ultrasonic transducer 96 is located at or near a top
of the blood reservoir 92 and transmits ultrasonic waves 98
downward through the air above the fluid (e.g., blood) towards the
interface 94. In these embodiments, the blood level in the
reservoir is then calculated by subtracting the detected space
between the top of the reservoir and the interface 94 from the
known overall height of the reservoir. In some embodiments, a cable
99 transmits a signal from the ultrasonic transducer 96 while in
other embodiments this is done wirelessly. A primary difference
between the embodiments shown in FIGS. 12 and 13 is that in FIG.
12, the interface 84 is detected from below, or through the blood,
while in FIG. 13 the interface 94 is detected from above.
[0079] In the various embodiments of FIGS. 12 and 13, the
ultrasonic transducer 86, 96 may be either a structurally separate
component adapted for coupling to the blood reservoir or the
ultrasonic transducer 86, 96 may be structurally integrated into
the blood reservoir. By way of example, the transducer may be a
separate component which is adapted for coupling to the blood
reservoir by an end user. Any of a variety of coupling techniques,
including for example, adhesive, snap fit, interference fit,
mechanical fasteners, and other known techniques may be employed by
the end user to couple the ultrasonic transducer to either an upper
surface (e.g., a lid) or a lower surface of the blood reservoir. In
some embodiments, a hole or opening is formed in the blood
reservoir, so that the ultrasonic transducer may communicate
directly (i.e., without passing through a wall of the reservoir)
with an interior chamber of the blood reservoir. By way of example,
the ultrasonic transducer may also be structurally integrated into
the blood reservoir by integrating the transducer during the
molding process for forming the blood reservoir, including either a
main body of the reservoir or a lid of the reservoir. In either
case (i.e., structurally integrated or structurally separate), the
end user must electrically couple the ultrasonic transducer to a
controller or other device for receiving a signal from the
transducer.
[0080] In some embodiments, as shown for example in FIG. 17, an
ultrasonic transducer such as the ultrasonic transducer 160 is
disposed within or otherwise coupled to a structure that reduces
potential interference or parasitic effects from other portions and
components (e.g., blood filters) that may typically be located
within the interior chamber of the blood reservoir. This
configuration may help reduce the impact of internal components or
reservoir wall condensation on the propagation of the ultrasonic
wave, which in turn may improve the accuracy of the sensor
measurements.
[0081] As shown in FIG. 17, a blood reservoir 150 has a blood
volume defining an interface 152 between the volume of blood and
the air or other fluid within the blood reservoir 150. A guide tube
154 having a top 156 and a bottom 158 extends downward into the
volume of blood. According to various embodiments, the bottom 158
of the tube 154 is located between about 1 and about 25 mm from a
bottom of the reservoir. According to some embodiments, the bottom
158 of the tube 154 is located between about 1 and about 10 mm from
a bottom of the reservoir. An ultrasonic transducer 160 is disposed
at or near the top 156 while the bottom 158 is open to the fluid
within the blood reservoir 150. The ultrasonic transducer 160 is
configured such that it generates ultrasonic waves directed
generally along a longitudinal axis of the tube 154 toward the
bottom of the reservoir (i.e., the blood contained within the
reservoir). According to some embodiments, the top 156 of the guide
tube 154 is located inside the reservoir at or near the lid or
cover. According to other embodiments, the guide tube 154 passes
through the lid or cover of the reservoir 150, such that the top
156 is located above or outside of the reservoir 150. In these
embodiments, the transducer 160 may be attached or otherwise
coupled to, at, or near the top 156 of the guide tube 154.
[0082] In various embodiments, the tube 154 includes openings
and/or the top 156 of the tube is spaced from the top (e.g., lid or
cover) of the blood reservoir to allow airflow into and out of the
tube 154. According to exemplary embodiments, the tube 154 includes
one or more holes in a wall of the tube near the top 156. According
to various embodiments, these holes are sized with a diameter
selected to reduce or eliminate the surface tension effect in the
event blood reaches the hole. According to various embodiments,
these holes are sized with a diameter selected to allow pressure
equalization inside and outside of the tube, such that the blood
level inside the tube is equal to or substantially equal to a blood
level outside of the tube. According to some embodiments, the hole
(or holes) is located at a location along the tube 154, which is
inside the reservoir 150. According to other embodiments, the hole
(or holes) is located at a location along the tube 154, which is
outside the reservoir 150.
[0083] In some embodiments, the guide tube 154 may function as a
waveguide for the ultrasonic waves. The ultrasonic waves emitted by
the ultrasonic transducer 160 will propagate downward through the
interior of the tube 154 and may not extend laterally outside the
tube 154. The tube 154 may be dimensioned accordingly. In some
embodiments, the tube 154 defines an interior chamber or lumen
having an inner diameter of about 4 to about 16 millimeters. In one
exemplary embodiment, the tube 154 has an outer diameter of about
16 millimeters and in inner diameter of between about 14 and about
15 mm. In some embodiments, the tube 154 may have any inner
diameter sufficiently large to allow for the blood level inside the
tube to be equal or substantially equal (e.g., within 0-5 percent)
of the blood level in the reservoir outside of the tube. For
example, in various embodiments, the inner diameter of the tube is
selected so as to avoid or substantially eliminate any Venturi
effect within the tube. In various embodiments, the tube 154 is
disposed within the blood reservoir in a substantially vertical
fashion (e.g., parallel or substantially parallel to the outer
walls of the reservoir). In other embodiments, the tube 154 extends
through the reservoir at some angle, for example at an angle of
between 5 and 45 degrees, with respect to the vertical
orientation.
[0084] In some embodiments, the guide tube 154 has an outer
diameter of about 16 millimeters and in inner diameter of between
about 14 and about 15 mm, and a vent hole diameter at or near the
top 156 of the tube 154 of between about 1 and about 5 mm.
According to some embodiments, the guide tube 154 as an inner
diameter of about 10 mm and a vent hole having a diameter of about
5 mm, where the vent hole is located inside the reservoir.
[0085] In some embodiments, a blood volume may be calculated based
upon a detected fluid level within the tube 154 that is
extrapolated to the blood reservoir 150. By detecting the fluid
level within the tube 154, rather than in the entire blood
reservoir 150, improvements in accuracy may be obtained because
potentially interfering elements and materials such as blood
filters are excluded from the ultrasonic measurements.
[0086] According to various embodiments, a polyurethane sheet is
disposed inside the tube 154. In these embodiments, in the event
the blood level reaches the top of the reservoir, the polyurethane
will prevent blood from contacting the piezoelectric transducer,
which may not be separately sterilized. In these embodiments, the
polyurethane is chosen with a thickness sufficiently small to allow
the ultrasonic waves to pass therethrough.
[0087] In some embodiments, the blood volume sensor may be an
infrared (IR) light sensor. In some embodiments, an infrared light
source positioned at or near a lower surface of the blood reservoir
82 may be used to locate a fluid/air interface within the blood
reservoir 82 by transmitting infrared light towards the interface.
Alternatively, the infrared light sensor may be located above the
interface. In some embodiments, the infrared light sensor may be
located a short distance away from the blood reservoir 82 and thus
can be attached to a mechanical holder for the blood level
reservoir 82.
[0088] In some instances, the infrared light is reflected back
towards the infrared light sensor. By measuring the reflectance,
the location of the interface may be determined. In some
embodiments, the infrared light travels through the blood to an
infrared light sensor located opposite the infrared light sensor.
By detecting changes in the received light, the interface location
may be determined. By combining the interface location with known
geometric parameters of the blood reservoir 82, the controller 20
can determine the blood volume within the blood reservoir 82. In
some embodiments, this information is transmitted wirelessly to the
controller 20.
[0089] In some embodiments, as shown in FIG. 14, an ultrasonic
blood volume sensor may include a pair of ultrasonic transducers
(e.g., piezoelectric crystals). FIG. 14 shows a blood reservoir 100
that includes a side wall 102 containing a volume of blood. A first
ultrasonic transducer 104 and a second ultrasonic transducer 106
are each secured to the side wall 102. In some embodiments, the
first ultrasonic transducer 104 and/or the second ultrasonic
transducer 106 may be a disposable ultrasonic transducer such as
that described in U.S. Pat. No. 6,694,570 or U.S. Pat. No.
7,694,570, both of which are hereby incorporated by reference. In
some embodiments, the first and second ultrasonic transducers 104,
106 may, for example, be adhesively secured to the side wall 102.
In various embodiments, conductors 108 and 110 provide electrical
communication between the first and second ultrasonic transducers
104, 106 and an unseen controller. In other embodiments, the first
and second ultrasonic transducers 104, 106 may instead communicate
wirelessly using any technique known in the art. In some
embodiments, the controller may be similar to the controller 60
discussed previously with respect to the perfusion system 52.
[0090] In operation, the first ultrasonic transducer 104 produce a
pulse of sonic energy that causes a flexural (e.g., elastic) wave
112 in the side wall 102, which then propogates or travels through
the side wall 102. The second ultrasonic transducer 106 then
receives the flexural wave 112. In this, designation of first and
second, particularly as shown, is illustrative only. It will be
appreciated that the first and second ultrasonic transducers 104,
106 may be arranged in any desired arrangement with respect to one
another. They are not required, for example, to be arranged with
the first ultrasonic transducer 104 being vertically above the
second ultrasonic transducer 106.
[0091] In some instances, the relative amount of liquid within the
blood reservoir 100 may cause phase delays in the signal received
by the second ultrasonic transducer 106. As there is a
substantially linear relationship between the amount of the phase
delay between the received components and the height of the blood
level inside the reservoir 100, a controller may calculate a fluid
level, or a change in the blood level, by analyzing the phase delay
in the signal. According to some embodiments, the correlation
between the phase delay and the level of blood in the reservoir 100
is determined experimentally by measuring the calculated phase
delay at various blood levels. In some embodiments, for example, a
phase delay is measured when the reservoir 100 is empty. As blood
enters the reservoir 100, the speed of the flexural wave slows. In
some embodiments, the decrease in speed may be correlated to a
liquid level. According to various embodiments, the blood level in
the reservoir 100 may be calculated using one or more of the
techniques described in U.S. Pat. No. 6,631,639, which is hereby
incorporated by reference in its entirety.
[0092] FIG. 15 shows an exemplary technique for attaching the
ultrasonic transducers to the blood reservoir 114. As shown, an
ultrasonic transducer 118 is releasably secured to the side wall
116. In some embodiments, the ultrasonic transducer 118 includes a
housing 120 and a piezoelectric element 122 disposed within the
housing 120. In some embodiments, the ultrasonic transducer 118
includes a section of double-sided tape 124. The tape 124 includes
a first side 126 that is or can be adhesively secured to the
housing 120 and a second side 128 that is or can be adhesively
secured to the side wall 116 of the blood reservoir 114.
[0093] FIG. 16 is an illustration of the ultrasonic transducer 118
free from the blood reservoir 114. In some embodiments, the
ultrasonic transducer 118 may be marketed already attached to the
blood reservoir 114. In some embodiments, the ultrasonic transducer
118 may be attachable at the point of use to any desired hard shell
blood reservoir or soft shell reservoir. In some embodiments, a
release liner 130 may be disposed on the second side 128 of the
double face tape 124. The release liner 130 permits the ultrasonic
transducer 118 to be handled yet can easily be removed in order to
attach the ultrasonic transducer 118 to a blood reservoir.
According to various embodiments, the ultrasonic transducer 118 is
configured as described in U.S. Pat. No. 6,694,570 or U.S. Pat. No.
7,694,570.
[0094] While not illustrated, the ultrasonic transducer 118 may
include one or more conductive wires that carry signals between the
ultrasonic transducer 118 and a controller such as the controller
60 described above with respect to the perfusion system 52. In some
embodiments, the ultrasonic transducer 118 may communicate
wirelessly with the aforementioned controller.
[0095] Various modifications and additions can be made to the
exemplary embodiments discussed without departing from the scope of
the present invention. For example, while the embodiments described
above refer to particular features, the scope of this invention
also includes embodiments having different combinations of features
and embodiments that do not include all of the above described
features.
* * * * *