Organ preservation apparatus

An organ preservation apparatus including an organ-receiving chamber, a pulsatile pump in continuous uninterrupted liquid communication with the organ-receiving chamber, and a fluid delivery tube interconnected between the organ-receiving chamber and the pulsatile pump for passing the organ preservation fluid from the organ-receiving chamber to the pulsatile pump. The pulsatile pump is configured to pass an organ preservation fluid to the organ-receiving chamber in a dichrotic pulse pattern. The organ-receiving chamber has an outer box with an insulated interior area, an organ-receiving cassette removably contained within the insulated interior area, and a lid detachably fastened to the outer box. The pulsatile pump includes a bladder pump, a motor, and a cam connected to the motor. The cam is connected to an actuator so as to compress the bladder pump is a dichrotic pulse pattern. A pressure transducer is connected to the fluid passageway between the pulsatile pump and the organ-receiving chamber so as to measure diastolic and systolic fluid pressure.

TECHNICAL FIELD 
The present invention relates to methods and apparatus for preserving human 
organs outside of the body. More particularly, the present invention 
relates to apparatus suitable for the transport and storage of human 
organs prior to transplantation. 
BACKGROUND ART 
Heretofore, there have been many difficulties and inconveniences in the 
process of transplanting human organs from one person to another. For 
example, patients waiting to receive an unrelated donor kidney have to be 
on constant standby in the hospital, sometimes for weeks. When the donor 
appeared, the timing was very important, for the surgery had to be 
substantially simultaneous so that immediately upon removal of the kidney 
from the donor, it could be transplanted into the patient. This meant that 
there had to be at least two surgical teams working on the 
transplantation. The donor and the patient had to be located very close to 
each other during these operations, because there was no practical way of 
preserving the kidneys for any substantial period of time after they had 
been removed from the donor body and before they were transplanted into 
the patient's body. The procedure was always therefore an emergency 
procedure and was fraught with risks as well as difficulties. Similar 
problems and the same difficulties have applied to the transplantation of 
other organs, such as a heart or liver. 
It has always been a goal in the preservation of human organs to make it 
possible to keep the organ alive for many hours and up to several days 
after harvesting the organ from the donor body. This would make it 
possible to use cadaver's kidneys, hearts, and livers and to have the 
harvesting operation and the transplant operation spaced apart by several 
days. The transplantation, therefore, could be an elective rather than an 
emergency procedure. Since additional time could be available, it would 
become possible to match the donor and recipient by tissue typing; 
unrelated donors who have proved compatible by tissue typing are generally 
as successful as donors who are related to the recipient. If additional 
time were available, and the organ could be preserved for a longer period 
of time, it would become possible for the recipient to wait at home until 
the correctly matched kidney or kidneys would become available. 
Furthermore, extra time would enable a single team of surgeons to do the 
harvesting operation and the transplanting operation. The surgery could be 
spaced apart by several days if necessary. Alternatively, the use of two 
teams could still be possible, but they would not need to be as close to 
each other at the time, for the organ to be transported substantial 
distances during the preservation time when the organ is being perfused 
outside of the body prior to transplanting. 
Previously, organs have been transported from the donor to the recipient by 
the use of common ice coolers. The organ is placed into static cold 
storage and delivered by hand from one hospital to another. The use of 
common ice coolers was developed because of the convenience of finding 
packaged ice at locations remote from the hospital. Unfortunately, the 
transport of kidneys in static cold storage has resulted in problems. 
Typically, intercellular acidosis will occur. Intercellular acidosis is 
the build-up of acids and other toxins in the organ. Eventually, these 
toxins will damage or destroy the organ. Another problem is the inducement 
of hypothermia into the stored organ. Over a period of time, the cold 
static storage may cause the organ cells to begin swelling and cause 
eventual failure. Acute tubular necrosis, or post transplant early organ 
dysfunction, occurs much more frequently in patients where the kidney is 
placed in static cold storage, causing the patient to require post 
transplant dialysis. As such, over the years, it was determined that 
pulsatile pumping action is necessary to maintain organ viability so as to 
preserve the organ for a longer period of time. 
U.S. Pat. Nos. 3,632,473 and 3,753,865 issued to Folkert O. Belzer et al. 
Dr. Belzer was an early pioneer in preservation technology for effectively 
storing human organs. These patents describe a system that incorporates 
the transfer of organs, such as kidneys, hearts, livers or other organs 
from the donor's body into a perfusion chamber where human plasma, kept in 
constant supply and preferably fortified with hormones and other 
substances, as pumped through the organ. In the perfusion chamber, the 
organ functions generally as it would in the body. For example, the 
kidneys in the perfusion chamber produce urine. The system maintained the 
organ at low temperatures so that the organ's activity is kept at a 
minimum. The plasma, which is circulated through the organ, is 
recirculated and oxygenated. The pH of the plasma is adjusted by a supply 
of carbon dioxide. Dr. Belzer's system utilized careful filtering so as to 
enable the plasma to be kept free from foreign matter. 
In Belzer's system, the pumping of the plasma through the organ is done by 
pulsatile pump such that pulses similar to those produced by the human 
heart are employed to force the cold plasma through the organ. Pressure is 
controlled with the aid of a damper having an air spring. The operation of 
the apparatus thus resembles the operation in the human body, but differs 
in the fact that it is being conducted at a very low temperature and in a 
type of controlled environment. In Belzer's system, in the transport and 
storage of kidneys, for example, it was not necessary to free the 
recirculated plasma from the small amount of urine produced during 
storage, for the freeing of the kidney from the urine can take place later 
in the patient's body after transplant. Pressures maintained on the organ 
are substantially those encountered by the organ in the human body. The 
flow of plasma through the organ is controlled in accordance with the 
pressure desired. In particular, the Belzer system utilized an air trap 
and the monitoring of the gauge pressures within the air trap so as to 
provide an indication of fluid pressure. 
Another system that has been used for the preservation of organs during 
transportation is identified as a "MOX-100 Renal Preservation System" and 
is sold by Waters Instruments, Inc. of Rochester, Minn. This system was 
designed to provide long term, unattended perfusion of one or two kidneys 
in the hospital or in the operating room. This device utilizes a 
disposable cassette for organ storage which is molded and placed within 
the system. The cassette provides membrane oxidation with a static 
membrane and gravity perfusate flow of up to 600 milliliters per minute. A 
complete circulatory system is provided including an arterial reservoir, a 
pump head, a heat exchanger, a bubble trap, a venous reservoir, a plasma 
flow meter, and a membrane oxygenating sack. The overall system connects 
the pulsatile pump chamber and gas and refrigeration sources to this 
cassette. The system includes visual and audio alarm systems which 
indicate pressure or temperature problems or input power failures. 
In Belzer's system and in Water's system, the fluid pressure to the organ 
is delivered mechanically. Additionally, each system utilizes a bubble 
trap so as to remove bubbles and gases from the organ preservation fluid. 
As a result, fluid pressure is measured from the bubble trap which 
contains air as well as solution. As such, the pressure was not a true 
blood pressure, but rather a gauge pressure which is dampened by the air 
in the bubble trap. It has been a common problem that both the Belzer 
system and the Waters system would occasionally damage the organ by over 
perfusing, causing irreparable damage by the application of pressures that 
were too great. There are no monitoring devices or safety devices to 
prevent the application of improper fluid pressure. Also, neither the 
Belzer or Waters system provides true dicrotic pulsatile action to the 
organ. As a result, accurate simulation of the human heart action was not 
accomplished by either of these systems. 
It is an object of the present invention to provide a human organ 
preservation apparatus that effectively preserves the life of the organ 
outside of the human body. 
It is a further object of the present invention to provide an human organ 
preservation apparatus that has the ability to salvage organs from 
non-heart beating donors. 
It is a further object of the present invention to provide a human organ 
preservation apparatus that effectively monitors diastolic and systolic 
pressures effecting the organ. 
It is another object of the present invention to provide a human organ 
preservation apparatus that effectively simulates dicrotic heart pumping 
action. 
It is another object of the present invention to provide a human organ 
preservation apparatus that maintains the organ in a cold environment. 
It is a further object of the present invention to provide a human organ 
preservation apparatus that simplifies monitoring and control 
requirements. 
It is still a further object of the present invention to provide a human 
organ preservation apparatus that provides a continuous and uninterrupted 
fluid flow from the pulsatile pump to the organ. 
These and other objects and advantages of the present invention will become 
apparent from a reading of the attached specifications and appended 
claims. 
SUMMARY OF THE INVENTION 
The present invention is an organ preservation apparatus that comprises an 
organ-receiving chamber, a pulsatile pump in continuous uninterrupted 
liquid communication with the organ-receiving chamber, and a fluid 
delivery tube interconnected between the organ-receiving chamber and the 
pulsatile pump. The pulsatile pump passes an organ preservation fluid to 
the kidneys placed in the organ-receiving chamber in a pressure waveform 
that resembles the internal pressure waveform and secondary dicrotic pulse 
pattern present inside the body with a normal heart beat. The fluid 
delivery tube serves to pass the organ preservation fluid through a 
membrane pre-filter in the organ-receiving chamber to the heat exchanger 
and back to the pulsatile pump. 
The organ-receiving chamber includes an outer box having an insulated 
interior area, an organ-receiving cassette removably contained within the 
insulated interior area, and a lid detachably fastened to the outer box 
over the organ-receiving cassette so as to maintain the organ-receiving 
cassette in a sealed environment. The outer box has a rigid exterior wall. 
The exterior wall has an inside surface having a flexible ceramic 
insulating coating. The insulated interior area is formed within the outer 
box and also has a ceramic insulating coating. The insulated interior area 
has an ice-receiving volume that generally surrounds the organ-receiving 
cassette. The organ-receiving cassette includes a main organ-receiving 
area having a filtered membrane extending across the bottom of the main 
organ-receiving area, and a funneled sump area that is fastened below the 
bottom of the main organ-receiving area so as to pass the organ 
preservation fluid to the fluid delivery tube. A heat exchange surface is 
formed exterior of the funneled sump area and extends downwardly below the 
main organ-receiving area. The fluid delivery tube extends around this 
heat exchange stand tube surface within the insulated interior area. 
The pulsatile pump comprises a bladder pump, a motor, and a cam system. The 
cam system is in driving connection with the motor such that the cam 
system rotates in relation to the motor. The cam system is in contact with 
a surface of the bladder pump so as to compress the bladder pump creating 
a dicrotic pulse waveform pressure pattern. The cam system particularly 
comprises a cam that is interconnected to the motor at a point on the 
surface of the cam, a cam follower in contact with the outer edge of the 
cam, and an actuator that is interposed between the cam follower and the 
bladder pump. The cam has an outer edge of varying radius from the point 
of connection to the motor. The cam follower follows the cam in such a 
manner that the cam follower moves to create a dicrotic pulse waveform 
pressure pattern. The actuator serves to compress the bladder pump in 
relation to the movement of the cam follower. 
The bladder pump includes a flexible bladder, a first one-way heart action 
valve positioned on one end of the flexible bladder, and a second one-way 
heart action valve positioned at the other end of the flexible bladder. 
The first one-way heart action valve allows the organ preservation fluid 
to pass from the flexible bladder toward the organ-receiving chamber. The 
second one-way heart action valve is interconnected to the fluid delivery 
tube such that the organ preservation fluid passes into the flexible 
bladder. The pulsatile pump system further includes an adjustable backstop 
that is in contact with the bladder pump. The adjustable backstop is 
movable so as to control the interior volume of the bladder pump. A closed 
circuit fluid passageway is connected to the bladder pump and extends in 
valved relationship to the organ-receiving chamber. This closed circuit 
fluid passageway forms a continuous uninterrupted liquid pathway, void of 
any air and without the use of a bubble trap. A flow through pressure 
transducer is connected to the fluid passageway for measuring the 
systolic, diastolic, and mean fluid pressure. This pressure transducer 
produces a non-damped pressure waveform signal indicative of such fluid 
pressures inside the body's circulatory system. 
An automated sensored manifold is connected in valved relationship to the 
closed circuit fluid passageway. This automated sensored manifold has a 
first outlet and a second outlet for fluid delivery to the organ-receiving 
chamber. In actual use, one outlet is connected to one kidney and the 
other outlet is connected to another kidney within the organ-receiving 
chamber. The automated sensored manifold has a first valve external of the 
organ-receiving chamber for controlling the organ-preservation fluid flow 
from the closed circuit fluid passageway to the first outlet. The 
automated sensored manifold also has a second valve that is external to 
the organ-receiving chamber for controlling the organ-preservation fluid 
flow from the closed circuit fluid passageway to the second outlet. The 
automated sensored manifold includes a hydrophobic microporus membrane 
that is connected to the closed circuit fluid passageway. This hydrophobic 
microporus membrane serves to sieve gas from the closed circuit fluid 
passageway and to effectively remove bubbles from the organ preservation 
fluid while maintaining a constant fluid pressure. As a redundant safety 
device, an ultrasonic bubble detector transducer is positioned on the 
closed circuit fluid passageway between the hydrophobic microporus 
membrane and the organ-receiving chamber. This ultrasonic bubble detector 
transducer detects bubbles in the organ preservation fluid. The ultrasonic 
bubble dector transducer is interconnected to the motor controller such 
that the motor stops upon a detection of a bubble within the organ 
preservation fluid. A pressure relief valve is also provided on the 
automated sensored manifold so as to allow excess fluid pressure to exit 
the system. This eliminates to possibility of excessive perfusing and 
prevents damage to the kidney. 
A visual display is connected to the pressure transducer so as to 
constantly display the systolic, diastolic, and mean fluid pressures 
effecting the preserved organ. The visual display is also connected to a 
temperature transducer in the organ-receiving chamber so as to provide a 
constant monitor of temperatures within the organ-receiving chamber. A 
strip chart recorder is interconnected to the pressure transducer so as to 
permanently record pressure information over time. A communications system 
and an alarm system is also provided so as to alert medical personnel, via 
onboard computer modem, of the need for attention to the organ being 
preserved.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIG. 1, there is shown at 10 the organ preservation apparatus 
in accordance with the preferred embodiment of the present invention. The 
organ preservation apparatus 10 comprises an organ-receiving chamber 12, a 
pulsatile pump 14, and a fluid delivery tube 16. As will be described 
hereinafter, the pulsatile pump 14 is in fluid communication with the 
organ-receiving chamber 12. The pulsatile pump 14 serves to pass an organ 
preservation fluid to the organ-receiving chamber 12 in a dicrotic pulse 
pattern. The fluid delivery tube 16 is interconnected between the 
organ-receiving chamber 12 and the pulsatile pump 14 so as to pass the 
organ preservation fluid from the organ-receiving chamber 12 to the 
pulsatile pump 14. 
The organ-receiving chamber 12 includes an outer box 18, an organ-receiving 
cassette 20, and a lid 22. The outer box 18 includes an insulated interior 
area 22. In normal use, this insulated interior are 22 contains the 
organ-receiving cassette 20 along with a supply of ice. The 
organ-receiving cassette 20 is a disposable cassette that is removably 
contained within this insulated interior area. The organ-receiving 
cassette 20 is made of a molded plastic material. Typically, the 
organ-receiving cassette 20 is made of PETG plastic. The outer box 18 has 
a generally rigid exterior wall 24 that forms the exterior of the organ 
preservation apparatus 10. This rigid exterior wall 24 has a generally 
rectangular configuration. The exterior wall 24 can be made of a rigid 
molded plastic. The exterior wall 24 should be sufficiently rigid to 
withstand the forces imparted upon it during the transportation of the 
organ preservation apparatus 10. The rigid exterior wall generally 
surrounds the organ-receiving chamber 12, the pulsatile pump 14, and the 
fluid delivery tube 16. 
Importantly, on the inside of the rigid exterior wall 24 is a flexible 
ceramic insulating coating 26. The ceramic insulating coating is applied, 
in a layer, to the inside of the exterior wall 24. This flexible ceramic 
insulating coating is a space age technology that was brought about by the 
development of the space shuttle. The flexible ceramic insulating coating 
is manufactured and sold by Insul-Coating Company of Houston, Tex. The 
flexible ceramic insulating coating, when applied to the inside of the 
exterior wall 24 effectively prevents heat intrusion from entering into 
the box 18. This flexible ceramic insulating coating is also applied to 
the exterior of the insulated interior area 22. The flexible ceramic 
insulating coating is applied to the insulated interior area so as to 
retain the cool temperatures caused by the filling of the insulated 
interior area 22 with ice. A foam insulation 28 may be interposed between 
the exterior wall 24 and the insulated interior area 22 so as to provide 
additional and further insulation. The foam insulation 28 can also provide 
shock absorption to the organ preservation apparatus. After 
experimentation, it was found that the arrangement of insulation described 
herein enabled the ice to maintain an effective cooling temperature for 
greater than ten hours without replacement. In the scheme of organ 
preservation, the ability to retain the cool temperatures of the ice for a 
longer period of time enables the organ to be preserved for a longer 
period of time. Additionally, the ability to avoid ice replacement within 
the insulated interior area 22 helps to avoid exposure of the organ to the 
external environment. 
It can be seen that an external refrigeration connection 30 opens at 32 at 
the exterior wall 24 of the outer box 18. This external refrigeration 
connection 30 communicates with the insulated interior area 22. A suitable 
refrigeration unit can be connected to the external refrigeration 
connection so as to provide additional cooling capacity to the insulated 
interior area 22. This cooling capacity can be introduced without the need 
to open the organ preservation apparatus 10 and to expose the organ to the 
external environment. 
It can be seen that the insulated interior area 22 includes an 
ice-receiving volume that generally surrounds the organ-receiving cassette 
20. This is in contrast to prior art devices in which the organ-receiving 
cassette is maintained separate from (i.e., generally above) the 
ice-receiving volume. In prior art technology, the organ-receiving 
cassette was maintained at a different level than the ice. The cool 
temperatures were imparted to the organ-receiving cassette through heat 
exchange with the tubing running through ice or refrigeration to the 
organ-receiving cassette. The present invention is an improvement over 
these prior technologies by placing the organ-receiving cassette at a 
level in which the ice can generally surround the organ-receiving 
cassette. As such, even in the event of a failure of the refrigeration 
system, the organ will be maintained in cold static storage within the 
organ-receiving cassette. 
The organ-receiving cassette 20 comprises a main organ-receiving area 34, a 
funneled sump area 36, and a heat exchange stand tube surface 38. The main 
organ-receiving area is a molded plastic area that has a suitable volume 
for receiving two (2) kidneys or other organs. The main organ-receiving 
area 34 is fitted within the insulated interior area 22. The main 
organ-receiving area includes a membrane 40 extending across the bottom of 
the main organ-receiving area. The membrane 40 acts as a pre-filter. It 
also provides the doctor with a surface to suture the kidney to. When it 
is necessary to transport the kidney within the organ-receiving cassette 
20, it is generally necessary to fix the position of the kidney so that it 
does not move about. The felted fibrous membrane 40 provides such a 
surface to suture the kidney to, so that the kidney is stabilized during 
transit. This felted fibrous membrane 40 also serves to filter out dried 
blood cells or fat globules from the circulation system. A funneled sump 
area 36 is formed below the membrane 40. This funneled sump area 36 
receives the drainage from the circulation system and from the kidney 
within the organ-receiving cassette 20. As organ preservation fluid passes 
from the kidney contained within the main organ-receiving area, the 
slanted walls of the sump area 36 delivers the fluid into the opening 42 
of the fluid delivery tube 16. A heat exchange stand tube surface 38 is 
formed exterior of this funneled sump area 36 and extends downward into 
the insulated interior area 22. In normal usage, this heat exchange stand 
tube surface 38 will be surrounded with ice. By wrapping the fluid 
delivery tube 16 around the exterior of the heat exchange stand tube 
surface 38 (in the manner illustrated in FIG. 1), additional heat exchange 
effects occur between the ice within the insulated interior area 22 and 
the organ preservation fluid contained within the fluid delivery tube 16. 
The fluid delivery tube 16 is a flexible plastic tubing of suitable length 
for wrapping around the heat exchange stand tube surface 38. As shown in 
FIG. 1, the heat exchange stand tube surface 38 is of a cylindrical 
configuration, although this should not be construed as a limitation on 
the present invention. The end of the heat exchange stand tube surface 38 
should be in close proximity to the bottom 44 of the insulated interior 
area 22. 
In FIG. 1, it can be seen that the lid 22 of the organ preservation 
apparatus 10 is fitted across the top surface of the organ-receiving 
chamber 12. The lid 22 also has a rigid exterior surface 46 of a material 
similar to that of the rigid exterior wall 24 of the outer box 18. A 
suitable seal 48 is interposed between the bottom edge 50 of the lid 22 
and the top edge 52 of the outer box 18. When the lid 22 is affixed in 
position, the seal 48 will preserve the cool temperatures within the 
interior of a organ-receiving chamber 12 and to prevent contamination from 
entering into the organ-receiving cassette 20. The lid 22 includes a 
suitable flexible ceramic insulating coating along the inner surfaces of 
the lid 22. This insulated surface corresponds to the area of the 
organ-receiving chamber 12. Suitable latches are provided so as to secure 
the lid 22 in position over the exterior of the organ-receiving chamber 
12. When the lid 22 is secured over the organ-receiving chamber 12, the 
organ preservation apparatus 10 is in suitable condition for 
transportation. The organ preservation apparatus 10 thus becomes a sealed 
unit that can be carried and transported easily. The composition of 
material that is used to make the outer box 18 and the lid 22 is of a 
strong but lightweight material. Ultimately, the overall weight of the 
organ preservation apparatus 10 is much less than any prior art pulsatile 
preservation apparatus. The ceramic insulating coatings used so as to 
maintain the cool temperatures within the organ-receiving chamber 12 have 
been selected because the coatings are lightweight and provide significant 
insulating capacity. It can further be seen that a foam insulation 52 is 
contained within the area between the interior wall 54 and the exterior 
wall 46 of lid 22. Another portion 56 of lid 22 extends, in sealed 
fashion, over the control panel for the organ preservation apparatus 10 of 
the present invention. 
FIG. 1 further shows the interior components of the control panel 58 of the 
present invention. To provide power to the system, a twelve-volt battery 
60 is contained on the interior 62 of control panel area 58. A transformer 
64 is also positioned within this interior area 62. The use of the battery 
60 allows the organ preservation apparatus 10 to be transported from place 
to place without the need for external electrical power. However, a 
standard 115-volt electrical system has been incorporated within the 
apparatus of the present invention as a backup system if the battery 60 
should become dead. When the apparatus 10 is placed in the hospital 
environment, or placed in proximity to an electrical outlet, then the 
electrical system can rely upon a standard 115-volt alternating current. 
A computer monitoring system 66 is provided on circuit panel 68 within the 
interior area 62 of the control panel 58. The computer monitoring system, 
as will be described hereinafter, monitors the various conditions 
effecting any organ contained within the organ-receiving chamber 12. The 
computer monitoring system can monitor temperature, pressure, power 
requirements, fluid flow, and other items. The computer monitoring system 
66 can transmit such information to a display located on the surface of 
the control panel 58. It can also transmit such information to a strip 
recorder so as to provide permanently recorded information concerning the 
conditions affecting the organ within the organ preservation chamber 12 
over a period of time. 
A motor controller 70 is also provided on the circuit panel 68. The motor 
controller 70 maintains the motor which operates the pulsatile pump (to be 
described hereinafter) at a constant sixty beats per minute. In order to 
maintain the viability of the organ contained within the organ-receiving 
chamber, it is important to provide a pulsatile pumping action of exactly 
sixty beats per minute. The use of the electronic motor controller 70 
provides this constant sixty beats per minute regardless of resistance 
between the motor and the pump. In the preferred embodiment of the present 
invention, a 66 to 1 gear ratio is provided. The use of this motor 
controller adds power to the motor if the resistance starts to reduce the 
pumping action below sixty beats per minute. As such, the motor controller 
70 maintains and assures a constant sixty beats per minute pumping rate, 
regardless of any reasonable resistance to such pumping action. 
A micro-motor 72 is electrically connected to the motor controller 70. The 
micro-motor 72 is an aircraft standard motor of relatively small size but 
high power output. The high power output is necessary so as to maintain 
the sixty beats per minute pulsatile rate under all conditions of 
resistance. The micro-motor 72 is also designed so as to be operated in 
extremely cold temperatures. Prior art technologies incorporated standard 
electric motors that did not have the capacity to operate efficiently at 
temperatures below 4020 F. The aircraft style micro-motor 72 is 
particularly designed for operation at low temperatures or at various 
temperature extremes. The motor 72 is powered by the battery 60. A gear 
head 74 connects the motor 72 with the pulsatile pump 14. As described 
herein previously, the gear head 74 provides a 66 to 1 gear ratio between 
the motor 72 and the pulsatile pump. The gear head 74 also actuates the 
cam mechanism so as to provide the dicrotic pulse pattern for the pumping 
action. 
A linear potentiometer is also provided in association with the control 
panel 14. A linear potentiometer 76 provides an electronic output of fluid 
flow through the pump. The linear potentiometer is spring loaded and 
connected to the backstop of the pump (to be described hereinafter). This 
linear potentiometer provides an output, to the computer monitoring system 
66, of the amount of fluid displacement. Calculations are carried out 
within the processor of computer 66 to provide an output corresponding to 
the fluid flow through the pump. In contrast with the prior art, the 
electronic monitoring of fluid flow is carried out in a better 
non-intrusive manner than the mechanical methods of flow measurement in 
the prior art. The fluid flow measurement scheme of the present invention 
is not invasive of the fluid flow within the system. Rather, the flow 
measurement is carried out external of the fluid flow system. 
FIG. 1 shows the backstop 78 that rests against the bladder pump 80. The 
backstop 78 is an adjustable mechanism that is used to regulate the volume 
of fluid within the bladder pump 80. This configuration is described in 
greater detail in connection with FIG. 3. A one-way heart action valve 82 
is provided at one end of the bladder pump 80 so as to allow fluid to flow 
from the fluid delivery tube 16 into the bladder pump 80. The one-way 
heart action valve 82 prevents any fluid within the bladder pump 80 from 
passing from the bladder pump 80 back into the fluid delivery tube 16. The 
interaction of the motor 72, the gear head 74, the backstop 78, and the 
bladder pump 80 serves to send the organ preservation fluid toward any 
organ contained within the organ-receiving cassette 20. Importantly, the 
present invention incorporates the use of the automated sensored manifold 
82 so as to control the closed circuit fluid flow to the organs within the 
organ-receiving cassette 20 and to cause any bubbles or gases to be 
removed from the closed circuit fluid flow. 
The automated sensored manifold 82 includes an external flow control 
actuator 84 that has suitable mechanisms for actuation. It can be seen 
that the flow control actuator 84 has a plunger 86 that can be actuated so 
as to terminate fluid flow to one or both kidneys. When activated, the 
plunger 86 closes the fluid flow to the tube 88. When opened, fluid flows 
in a normal fashion through the tube 88. The plunger 86 is external to the 
organ preservation fluid pathway. In contrast to prior art systems, the 
present invention allows the opening and closing of fluid flow pathway to 
the organ from an area external to the organ-receiving cassette 20. In 
this manner, the attendant to the device never has to come into contact 
with the organ. Typical prior art techniques used clamps, and other 
mechanisms, to stop the fluid flow. The use of the external flow control 
actuator as part of the present invention eliminates the need to ever 
enter the receiving chamber 20 for the purpose of stopping the fluid flow 
to one or both kidneys. As will be described hereinafter, the automated 
sensored manifold 82 can divide the pulsatile fluid flow into two 
pathways. In normal organ preservation techniques, two kidneys are 
preserved simultaneously. Each of the fluid pathways would transmit organ 
preservation fluid to a separate kidney (or other organ). 
An important feature of the present invention, that is not shown in prior 
art technology, is the use of the hydrophobic microporus membrane 90 in 
conjunction with the automated sensored manifold 82. The hydrophobic 
microporus membrane acts as a sieve for separating gas from liquid the 
aqueous fluid. The hydrophobic microporus membrane removes any gases from 
the aqueous fluid flow. It is important to organ preservation that gases 
not enter the organ or block the aqueous fluid flow. In prior art 
technology, bubble traps were used so as to trap the air in an area away 
from the fluid delivery tubes, yet within the fluid flow system. The use 
of the hydrophobic microporus membrane 90 eliminates the need for the 
bubble traps by automatically venting/eliminating any air or other gases 
from the system and, at the same time, maintains a continuous pressurized 
uninterrupted aqueous liquid circulation circuit between the pump 80 and 
the organ within the organ-receiving cassette 20. 
In the event that a bubble remains after the liquid passes through the 
hydrophobic microporus membrane 90, an ultrasonic air bubble transducer 94 
is connected to the fluid flow 88. The ultrasonic bubble transducer 94 
clamps onto the tubing but does not interrupt fluid flow. A circuit drives 
one transducer which projects ultrasonic energy across the tubing and its 
contents. A second transducer acts as a receiver, sensitive to the 
ultrasonic energy transmitted across the fluid path. When a bubble passes 
through the sensor, the path of acoustic energy is interrupted. From the 
received transducer signal, the circuit is capable of not only detecting 
the presence of bubbles in the fluid, but can also accurately 
differentiate bubble sizes and empty line conditions. Such an ultrasonic 
air bubble sensor is manufactured by Zevex, Inc. of Murray, Utah. In the 
event of a bubble passing through the fluid delivery tube 88, the 
ultrasonic bubble transducer 94 will transmit a signal to the motor 
controller 70 so as to shut down the pumping system. Since this occurs 
virtually instantaneously, the air bubble will not reach the organ. When 
the motor 72 is shut down, the system reverts to a cold static storage 
system. The configuration of the one-way heart action valves, the 
hydrophobic microporus membrane, the pressure relief vales, and the bubble 
transducer, effectively prevents the system from injuring or excessively 
perfusing the organ. 
As an additional feature of the present invention, a pressure relief valve 
is provided on the automated sensored manifold 82. This pressure relief 
valve is of a standard configuration. When the pressures in the fluid 
delivery tube 88 reach a certain level, the pressure relief valve will 
open up so as to reduce the pressures affecting the organ. The pressure 
relief valve may release fluid in amounts sufficient to bring the fluid 
pressures to a reasonable range. The pressure relief valve acts as an 
additional safeguard to further prevent injury to the organ or excess 
pressures from over perfusing the organ. The pressure relief valve further 
assists in the self-priming of the system. 
FIG. 2 shows the organ-receiving cassette and related items. In normal use, 
the items shown in FIG. 2, are the disposable items associated with the 
organ preservation apparatus 10. These disposable items are replaced after 
every kidney and other human organ transport. The replacement of these 
items is necessary so as to preserve the sterile conditions associated 
with organ transport and storage. Virtually all of the items shown in FIG. 
2 are made of molded plastic materials. The organ-receiving cassette 100 
is shown in its generally rectangular configuration having the felted 
membrane 102 at its bottom. It can be seen that the sump 104 directs fluid 
flow to the inlet 106 associated with the fluid delivery tube 108. Fluid 
delivery tube 108 extends around the heat exchange stand tube surface 110 
of the organ-receiving cassette 100. By wrapping the fluid delivery tube 
108 in the manner shown in FIG. 2, the fluid within the tube 108 is 
exposed for suitable heat exchange with any ice contained within the 
insulated interior of the outer box. After wrapping around the heat 
exchange stand tube surface 110, the fluid delivery tube 108 extends 
upward so as to connect at 112 to fluid delivery tube 114. The pumping 
action by the bladder pump 116 causes the organ preservation fluid within 
the fluid delivery tube 108 to pass in the pattern shown in FIG. 2. In the 
fluid delivery tube 114, a disposable lure thermistor temperature probe 
118 is fitted. This temperature probe 118 is connected to the computer 
monitor 66 (shown in FIG. 1) so as to provide suitable temperature 
information as to the conditions of the organ preservation fluid within 
tube 114. If the temperature of the organ preservation fluid is too high, 
then a suitable signal is transmitted to the computer 66, and to the 
display panel, so as to warn the user to introduce additional ice into the 
insulated interior or to otherwise cool the interior of the system. 
Any organ preservation fluid in tube 114 will pass into the bladder pump 
116. Ultimately, the organ preservation fluid in the tube 114 will enter 
the one-wa heart action valve 120 at the bottom of bladder pump 116. The 
one-way valve 120 is a specially designed valve which allows the fluid to 
enter the bladder pump 116 while preventing the fluid from flowing 
downwardly from the bladder pump 116 into the tube 114. As can be seen, 
the bladder pump 116 includes an interior area that represents a pumping 
volume. By changing the amount of volume within the bladder pump 116, the 
amount of fluid that can be pumped by the system of the present invention 
can be correspondingly changed. Another one-way valve 122 is attached at 
the opposite end of the bladder pump 116. One-way valve 122 allows the 
organ preservation fluid to flow from the bladder pump 116 into the tube 
124. The one-way valve 122 prevents any fluid from flowing from the tube 
124 back into the bladder pump 116. The arrangement of the one-way valves 
120 and 122 effectively resembles the valve action on human hearts. By 
using these one-way valves 120 and 122, a suitable unidirectional flow of 
organ preservation fluid is established. 
Fluid delivery tube 124 extends from the pump 116 through the seal 126 
between the display panel and the organ-receiving cassette 100. Tube 124 
then passes toward the automated sensored manifold 128. It can be seen in 
FIG. 2 that tube 124 eventually passes to a branch connection 130 adjacent 
to the automated sensored manifold 128. One portion of the fluid within 
the tube 124 will pass into the central area of automated sensored 
manifold 128. The hydrophobic microporus membrane 132, at this location, 
separates any gases from the liquid flow. The organ preservation fluid 
will then be divided into two pathways. As can be seen, the automated 
sensored manifold 128 has a first outlet 134 and a second outlet 136. The 
fluid from the fluid delivery tube 124 will pass outwardly, toward the 
organ within the organ-receiving cassette 100 through these outlets 134 
and 136. With the use of the valved action of the automated sensored 
manifold 128, the flow to the organs within the organ-receiving cassette 
100 can be effectively controlled. Any gas will pass outwardly through the 
hydrophobic microporus membrane 132. 
At the other end of the fluid delivery tube 124 is a disposable electronic 
pressure transducer 138. The organ preservation fluid will flow pass the 
branch 130 and into this pressure transducer 138. In contrast with prior 
art technologies, the use of the electronic pressure sensor 138 provides 
an effective measurement of diastolic and systolic fluid pressures. The 
prior art technologies always required the use of a bubble trap to remove 
any bubbles from the organ preservation fluid. However, whenever a bubble 
trap is used, an interrupted non-continuous liquid flow is created. As 
such, it is only possible to obtain a gauge pressure of the organ 
preservation fluid. The gauge pressure utilized in prior art technologies 
is quite different than the measurement of blood pressure. The measurement 
of blood pressure measures the systolic, diastolic, and mean pressures in 
the circulatory system. This more closely resembles the behavior of the 
blood within the human body. It was a common problem when measuring gauge 
pressure that the organ would eventually be damaged because of excessive 
perfusion, because the gauge pressure did not correspond accurately with 
the fluid pressures transmitted to the organ by pulsatile pumps. By using 
a closed uninterrupted fluid system, the present invention is able to 
measure a diastolic and systolic blood pressure while providing pulsatile 
pumping action. There is no air trap interruption of the closed circuit 
system of the present invention. The electronic flow-through pressure 
monitor 138 provides an electronic signal to the computer 66 of the 
present invention. This signal is then relayed, in the form of a visual 
display, of systolic and diastolic blood pressure, and can be continually 
monitored throughout the transport and storage of the organ within the 
system. Additionally, the pressure transducer 138 utilizes a lure lock 
fitting so that there is no need to prime the system prior to use. As 
such, the ability to use the electronic pressure transducer 138 within the 
system of the present invention is a significant improvement over prior 
art technologies of organ transportation and storage. 
In FIG. 2, it can be seen that the organ-receiving cassette 100 has a clear 
see-through cover 140 that can be placed over the top of the cassette 100. 
This assures additional sealing of the system, prevents external 
contamination from occurring, and retains the organ preservation fluid 
within the cassette 100. The cover 140 can be fitted over seals 126 and 
142 so as to provide a secure closed system. 
FIG. 3 shows the display panel 200 of the present invention. It can be seen 
that the display panel 200 is provided on the exterior surface of box 202 
in a location opposite to the organ-receiving chamber. The display panel 
200 is provided so as to provide humanly perceivable signals and controls 
as to the operation of the organ preservation system of the present 
invention. The battery, motors, computer, and controls are contained 
within the interior of box 202 rearward of the displays on the display 
panel 200. 
In FIG. 3, an illustration is provided of the pulsatile pump system 204. It 
can be seen that the bladder pump 206 is detachably mounted on the display 
panel 200. A motor 208 is provided, rearward of the display panel 200, so 
as to drive a cam system 210. The cam system 210 is in such driving 
connection with the motor that the cam system 210 rotates in relation to 
the motor. The cam system 210 is in contact with a surface 212 of the 
bladder pump 206. The cam system 210 compresses the bladder pump 206 in a 
dicrotic pulse pattern. 
The cam system 210 comprises a cam 214 which is interconnected to motor 208 
at a central point. The cam 214 has an outer edge of varying radius from 
the point 208. It is important to the embodiment of the present invention 
that the shape of the cam 214 provides a dicrotic pulse pattern. The term 
"dicrotic pulse pattern" is the double spike effect of the heart. Prior 
art technologies provided pulsatile action that was not of the "double 
spike" effect. Prior art pulsatile pumping technologies relied on a single 
spike to resemble heart pumping action. After experimentation, it was 
found that the dicrotic pulse pattern more accurately resembled the actual 
pumping action of the heart. 
A cam follower 216 is a bearing which is in rolling connection with the cam 
214. The bearing 216 rolls and moves in a dicrotic pulse pattern by being 
in constant contact with the outer edge of the cam 214. An actuator 218 is 
interposed between the cam follower 216 and the bladder pump 206. Actuator 
218 compresses the bladder pump 206 in relation to the movement of the cam 
follower 216. The rotation of the cam 214 at sixty revolutions per minute, 
and the movement of the actuator 218 in a dicrotic pulse pattern 
effectively creates a simulation of actual heart action. The compressing 
of the bladder pump 206 sends the fluid to the preserved organ in a manner 
closely resembling the actual pumping action of the heart. 
It should be kept in mind that any kidneys that would be stored would be of 
various sizes. A small kidney will require less organ preservation fluid 
than would a large adult-sized kidney. Accordingly, it is important to be 
able to adjust the amount of organ preservation fluid that can be received 
by the bladder pump 216 and, hence, delivered to the organ. In keeping 
with this principle, an adjustable backstop 220 is provided. The 
adjustable backstop 220 can be moved along pathway 222 so as to be brought 
in contact with a surface 224 of bladder pump 206. A thumbwheel 226 can be 
provided so as to move the backstop 220 as desired. As the backstop 
compresses the surface 224 of bladder pump 206, the volume on the interior 
of bladder pump 206 is reduced accordingly. The linear potentiometer can 
provide the operator with a proper analysis as to the volume of fluid 
within the compressed bladder pump 206. A lock be is provided so as to 
prevent the backstop 220 from moving out of its position. As described 
herein previously, the bladder pump 206 has a first one-way heart action 
valve 230 at its bottom end and a second one-way heart action valve 232 at 
its top end. Fluid passes through these one-way heart action valves in a 
manner further resembling the actual pumping action of the heart. 
A toggle switch 234 is provided as a safety switch. This is a locking 
toggle switch that prevents the organ preservation apparatus of the 
present invention from being inadvertently switched on or off. 
The automated sensored manifold system 236 is shown as having the actuator 
levers 238 and 240 as extending outside of the organ-receiving chamber. 
These automated sensored manifold levers are located outside of the 
storage system so as to keep the attendant from touching anything within 
the organ-receiving cassette. The actuators allow the flow to each of the 
organs to be adjusted as needed. In addition, the use of the actuator 
levers 238 and 240 assists in the installation of the kidney. It is always 
necessary to install one kidney at a time within the organ-receiving 
cassette. By closing the actuator lever for each kidney, during 
installation of the kidneys, the correct pressures can be properly 
adjusted for each of the kidneys. 
A liquid crystal display 242 is placed on the center of the display panel 
220. The liquid crystal display 242 provides the operator of the organ 
preservation apparatus a constant input of information concerning the 
conditions affecting the stored organ. The liquid crystal display 242 is 
connected to the computer in such manner that any signal generated by the 
computer is displayed on the display 242. The display 242 will present 
constant information concerning diastolic and systolic fluid pressures, 
temperature within the organ-receiving chamber, fluid flow, and other 
information. The constant feedback of information is an important feature 
of the present invention. For example, during the initial installation of 
the organ, the blood pressure should be kept at a desired level. However, 
after the fluid begins flowing through the organ, the organ will open up 
and the blood pressure will decrease somewhat. In order to maintain the 
blood pressure at a constant level, it is necessary to adjust the backstop 
220 by rotating the thumbwheel 226. The visual display 242 will then 
provide the operator with the necessary information so as to allow the 
proper adjustments to be made so as to control the correct fluid flow and 
pressure acting on the organ. Also, if the temperature within the chamber 
begins to warm, the display 242 will provide an indication to the operator 
that additional ice or refrigeration must be provided to the storage 
chamber. 
A touchpad membrane switch control system 244 is provided for the onboard 
computer 66. This touch control system provides interactive information 
with the computer so that the operator can properly control the operation 
of the organ preservation apparatus. The display 242 can be an interactive 
display in which the operator may need to key in information such as "yes" 
or "no". The use of this touchpad display 244 greatly simplifies the 
operation and use of the organ preservation apparatus. A strip chart 
recorder 246 is also provided on the display panel 200. The strip chart 
recorder can record information, such as that shown on display 242, over a 
period of time. This strip chart recorder 246 can be used to keep a 
constant and permanent record of conditions during organ transport. If a 
failure occurs during the transport of an organ, then the strip chart can 
be referenced so as to determine the nature of the failure. The strip 
chart can be maintained in the records for any future references that may 
be necessary and for further diagnostics on the kidney or other human 
organs or organ transport system. 
Various power indicator lights 248 are provided so as to indicate the 
operation of the system. The display panel 200 can also be modified in 
various ways. For example, a suitable audio or visual alarm system can be 
incorporated into the design of a panel so as to provide immediate 
information as to emergency conditions. Additionally, a communications 
package can be integrated with the computer and will incorporate a number 
of telephone numbers that the system could call in the event of an 
emergency. If the parameters of operation get outside of a given range, 
then an alarm goes off. If the system does not return to its proper 
operating parameters, the communications package could begin dialing the 
telephone numbers so as to notify the doctors or medical technicians. The 
doctors or medical technicians could call the machine back to get the 
detailed information as to what was happening with the stored organ. 
It is an important feature of the present invention that the organ 
preservation apparatus provides a fail/safe technique for preserving the 
organ. As stated previously, pressure relief valves, bubble detector 
sensors, and hydrophobic microporus membranes are utilized so as to 
prevent the organ from being damaged. Also, backup systems are 
incorporated in case of a failure of one or more components of the system. 
Very importantly, however, if the entire system fails, then the organ is 
not permanently damaged. Throughout the operation of the system, if 
failure occurs, then the system simply reverts to standard cold static 
storage. In the worse case possibility, the organ remains available for 
transport in standard fashion. 
FIG. 4 illustrates the shape of the cam 214. In FIG. 4, the radial distance 
from the center of the cam changes throughout the circumference of the 
cam. It can be seen that the graph of FIG. 4 illustrates a dicrotic pulse 
waveform. Area 302 is called the "dicrotic notch". All human heartbeats 
create this dicrotic notch pressure waveform within the circulatory 
system. In order to create a system that more accurately reflects the 
actual pumping operation of the heart and the pumping action in the human 
body, it is very important to duplicate the dicrotic notch waveform within 
the closed circuit pumping system. By shaping the cam in the manner 
illustrated in FIG. 3 and shown in FIG. 4, the ability to compress the 
bladder pump 206 in the manner of the dicrotic pulse is accomplished. 
The present invention can incorporate many types of organ preservation 
solutions. However, the preferred organ preservation solution is of a type 
described and developed by Folkert O. Belzer which utilized a kidney 
perfusate that contained Sodium Gluconate--100 mM/liter, includes 
hydroxyethyl starch and other additives (adenosine, glutathione, potassium 
phosphate, magnesium sulphate). Initial studies of this preservation 
solution indicated that it had a favorable metabolic effect on the kidney. 
This solution is pH stable. However, various other preservation solutions 
could be utilized within the system of the present invention. 
The present invention is an organ preservation apparatus that effectively 
duplicates the pumping operation of the heart during the storage of 
organs. Although the present invention has been described in conjunction 
with the storage and transportation of kidneys, it is adaptable to a wide 
variety of other organs such as hearts, pancreases, livers, and other 
human organs. 
In contrast with prior art technologies, the present invention is a 
significant improvement. First, the present invention perfuses the organ 
with a pulsatile dicrotic pulse patterns for preserving the organ. The 
present invention maintains the organ in a cold sealed environment. The 
present invention provides constant monitoring of the organ and constant 
input to the operator of the system. Importantly, accurate diastolic and 
systolic fluid pressures are measured. The present invention has overcome 
the problems of prior art systems by accurately measuring diastolic and 
systolic pressures, instead of gauge pressures from a system containing a 
compressed gas which damps the pressure reading. Prior art systems relied 
on gauge pressure since bubble traps and interrupted fluid delivery 
pathways were used. The use of the one-way heart action valves, the 
adjustment mechanisms, the air bubble removal and monitoring of the 
present invention make it virtually impossible to damage the organ during 
operation of the organ preservation system. The organ preservation 
apparatus, and the associated equipment, is relatively lightweight and 
transportable. Each of the items of the organ preservation system are 
self-contained and transportable. Therefore, the present invention offers 
significant improvements over any prior art organ storage, preservation, 
and transport systems available. 
The foregoing disclosure and description of the invention is illustrative 
and explanatory thereof. Various changes in the details of the illustrated 
apparatus may be made within the scope of the appended claims without 
departing from the true spirit of the invention. The present invention 
should only be limited by the following claims and their legal 
equivalents.