U.S. patent number 3,881,990 [Application Number 05/400,713] was granted by the patent office on 1975-05-06 for method of transporting and storing organs while retaining the organs in a viable condition.
This patent grant is currently assigned to Waters Instruments, Inc.. Invention is credited to Thomas A. Burton, Allen W. Moberg.
United States Patent |
3,881,990 |
Burton , et al. |
May 6, 1975 |
Method of transporting and storing organs while retaining the
organs in a viable condition
Abstract
In maintaining organs in a viable condition during transport and
subsequently in a hospital, the organ is placed in a cassette of a
transport module, the cassette having an organ receiving chamber, a
venous reservoir, an oxygenator, a pulsatile pump head and a heat
exchanger. After transport the cassette is removed from the
transport module and placed in an in-hospital support module. Each
of the modules has a pulsatile pump chamber, a gas source for
supplying oxygen, a cooling source to furnish a cooling fluid to
the heat exchanger, and pressure, temperature and pump rate
controls.
Inventors: |
Burton; Thomas A. (Rochester,
MN), Moberg; Allen W. (Minneapolis, MN) |
Assignee: |
Waters Instruments, Inc.
(Rochester, MN)
|
Family
ID: |
26897058 |
Appl.
No.: |
05/400,713 |
Filed: |
September 26, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
201739 |
Nov 24, 1971 |
3777507 |
Dec 11, 1973 |
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Current U.S.
Class: |
435/1.2 |
Current CPC
Class: |
A01N
1/0273 (20130101); A01N 1/0247 (20130101) |
Current International
Class: |
A01N
1/02 (20060101); C12k 009/00 () |
Field of
Search: |
;195/1.7 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rosen; Sam
Attorney, Agent or Firm: Dugger, Johnson & Westman
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a Divisional Application of our co-pending U.S.
Pat. Application Ser. No. 201739, filed Nov. 24, 1971, now U.S.
Pat. No. 3,777,507, granted Dec. 11, 1973.
Claims
What is claimed is:
1. In the method of preserving and maintaining an organ in a viable
state in a cassette that has a perfusate circulatory system that
includes an organ chamber, a venous reservoir, an oxygenator, a
heat exchanger, and an arterial reservoir, placing the cassette in
a manually portable transport module that has a cooling fluid
source for supplying cooling fluid to the cassette heat exchanger
and an oxygen source for supplying oxygen to the cassette,
transporting the combination of the cassette and transport module
to the site of a donor organ, placing the donor organ in the organ
chamber, and connecting the organ in the circulatory system to
perfuse the organ, transporting the combination of the cassette and
transport module to an organ transplant site that is remote from
said site of the donor organ, removing the cassette with the organ
therein from the transport module at the transplant site, and while
the organ is connected in the circulatory system, manually
transferring the cassette from the transport module to an
in-hospital support unit that has sources for supplying cooling
fluid and oxygen to the heat exchanger and oxygenator
respectively.
2. The method of claim 1 further characterized in the step of
pumping perfusate to the organ during the transport step from the
donor site to the transplant site, discontinuing pumping perfusate
during the transfer step and resume pumping perfusate to the organ
in the cassette after the cassette has been transferred from the
transport module to the in-hospital unit.
3. The method of claim 1 further characterized in that during the
step of transporting said combination from the donor site to the
transplant site, the step of supplying a mixture of carbon dioxide
and oxygen in contact with the oxygenator from a single source of a
mixture of carbon dioxide and oxygen in the transport module.
4. In the method of maintaining an organ in a viable state, placing
an organ in a cassette at an organ donor site including connecting
the organ in the cassette perfusate circulatory system that
includes a venous reservoir, an oxygenator and an arterial
reservoir, transporting the cassette with the organ therein in a
manually transportable transport module that has sources for
supplying oxygen and cooling fluid to the cassette from the donor
site to a remote in-hospital transplant site and at the transplant
site transferring the cassette from the transport module to an
in-hospital support unit that has a source for supplying cooling
fluid to the cassette and a source for supplying oxygen to the
cassette including supplying cooling fluid and oxygen to the
cassette from said unit sources, the last mentioned transferring
step including retaining the organ connected in said circulatory
system.
5. The method of claim 4 further characterized in that the
transporting step includes applying a pump pressure to the
perfusate in the circulatory system from a source contained in the
transport module and supplying oxygen and cooling fluid to the
cassette from the transport unit, and that after the transferring
step, applying a pump pressure to the perfusate in the circulatory
system from a source in the in-hospital unit.
6. The method of claim 1 further characterized in the steps of
conducting oxygen from the transport module oxygen source to the
oxygenator and cooling fluid from the transport module cooling
fluid source to the heat exchanger while the organ is in the
circulatory system and the cassette is in the transport module;
discontinuing the conduction of oxygen and cooling fluid from the
respective transport module source to the oxygenator and heat
exchanger prior to the transfer step, and after the transfer step
conducting oxygen and cooling fluid from the respective support
unit source to the oxygenator and heat exchanger respectively.
7. In the method of maintaining an organ in a viable state in a
cassette that has an organ perfusate circulatory system, including
an organ chamber; at an organ donor site, placing the organ in the
organ chamber including connecting the organ in the circulatory
system, transporting the cassette with the organ connected in the
circulatory system in a manually transportable transport unit from
the donor site to a remote in-hospital transplant site, including
circulating an oxygenated liquid through the circulatory system to
the organ; and supplying oxygen from the transport module to the
circulatory system to replenish the oxygen in the system; at the
transplant site while the organ is still connected in the
circulatory system, transferring the cassette from the transport
unit to an in-hospital support unit; and while the cassette is in
the support unit, circulating an oxygenated liquid through the
circulatory system to the organ and supplying oxygen to the
circulatory system to replenish the oxygen in the system.
8. The method of claim 7 further characterized in that the
transporting step includes cooling the liquid in the circulatory
system by using a source of cooling medium external to the cassette
and in the transport unit, and that while the cassette is in the
support unit, cooling the liquid in the circulatory system by using
a source of cooling medium external to the cassette and in the
support unit.
9. The method of claim 7 further characterized in that the
transporting step includes applying a pumping pressure to the
circulatory system from a source external to the cassette and in
the transport unit to force liquid to flow through the system to
the organ; and after the transferring step, applying a pumping
pressure from a source external to the cassette and in the support
unit to force liquid to flow through the system to the organ.
10. The method of claim 7 wherein the support unit is of a much
larger size than the transport module.
Description
BACKGROUND OF THE INVENTION
Apparatus for maintaining an organ in a viable state for
transplantation.
In the prior art it is old to provide units for maintaining organs
in a viable state, see for example U.S. Pat. Nos. 3,406,531 and
3,545,221. However, prior art units are large, bulky and expensive
to manufacture. Further, in organ transplant procedures, frequently
the donor organ, for example a kidney, is obtainable from a
hospital a considerable distance from the location of the hospital
where the transplant operation is to take place and it is necessary
to transport the organ to the transplant hospital. Prior art organ
preservation machines are so large that usually they are carried by
special trucks and require a technician to monitor them
continuously. In order to overcome problems such as mentioned
above, as well as others, this invention has been made.
SUMMARY OF THE INVENTION
For use in combination with a transport or larger in-hospital
support module containing a pump, gas under pressure and cooling
apparatus, a cassette having an organ receiving chamber, a venous
reservoir in gravity liquid flow communication with the organ
chamber and in part defined thereby, an oxygenator chamber below
the venous reservoir, a static membrane in the oxygenator chamber
to have liquid flow by gravity therethrough and having an inlet in
gravity liquid communication with the venous reservoir and an
outlet in gravity liquid flow communication with an arterial
reservoir, and a pump tube and heat exchanger in series for
conducting liquid from the arterial reservoir to the organ
chambers.
One of the objects of the invention is to provide a new and novel
disposable cassette having a complete circulatory system usable
with a transport module or an in-hospital console for maintaining
organs such as kidneys in a viable state. In furtherance of the
above-mentioned object, it is a further object of the invention to
provide a cassette that may be transferred between a transport
module and in-hospital console without need to disturb the organ
once placed in the circulatory system.
An additional object of this invention is to provide a new and
novel cassette of a generally box like shape that has a membrane
oxygenator, arterial and venous reservoirs, a heat exchanger, a
pump head and a bubble trap that may be transferred between a
transport module and an in-hospital console merely by disengagement
and reengagement of the pump head with the respective pump chamber,
changing connections for the cooling fluid of the heat exchanger
and changing sources of oxygen and carbon dioxide. In furtherance
of the above objects, it is a still further object to provide a
cassette that is nearly entirely made of plastic materials.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a transport module having a cassette
therein, portions of cover being broken away and the control panel
closure being shown in an open condition;
FIG. 2 is a side view of the cassette of this invention, said view
being generally taken along the line and in the direction of the
arrows 2--2 of FIG. 3;
FIG. 3 is a transverse cross-sectional view generally taken along
the line and in the direction of the arrows 3--3 of FIG. 2 and
additional diagrammatically showing portions of a module used with
the cassette;
FIG. 4 is an enlarged, fragmentary, transverse cross-sectional view
generally taken along the line and in the direction of the arrows
4--4 of FIG. 2 to more clearly illustrate structural features of
the organ receiving chambers and the venous reservoirs;
FIG. 5 is an enlarged, fragmentary horizontal cross-sectional view
with portions of the organ support plates broken away, said view
being generally taken along the line and in the direction of arrows
5--5 of FIG. 4;
FIG. 6 is a horizontal cross-sectional view generally taken along
the line and in the direction of the arrows 6--6 of FIG. 2;
FIG. 7 is a horizontal cross-sectional view generally taken along
the line and in the direction of the arrows 7--7 of FIG. 2 with
portions broken away to, in particular show the arterial
reservoir;
FIG. 8 is an enlarged, fragmentary cross-sectional view generally
taken along the line and in the direction of the arrows 8--8 of
FIG. 6 to more fully show the mounting of the oxygenator;
FIG. 9 is a vertical cross-sectional view of a sample port member
and adjacent line portions;
FIG. 10 is an enlarged fragmentary cross-sectional view of the
membrane oxygenator that more clearly shows the filter therein;
and
FIG. 11 is a perspective view of an in-hospital support unit having
the cassette of this invention mounted thereon, said view
schematically showing various component parts of said unit.
Venous reservoir 40 is formed by the organ support plate 17,
partition 29, and wall portions 42, 43 and 44 of walls 13, 14 and
11 respectively, plate portion 46a of a bottom planar plate 46 that
inclines downwardly from wall 12 toward wall 11, a generally
horizontal top wall 48 of a fluid passageway, generally designated
49 for the venous reservoir 41, and a vertical wall 50 of
passageway 49. The venous reservoir 40 is located directly beneath
the organ chamber 19, plate 46 having a drain aperture 51 in the
corner portion thereof that is adjacent the juncture of wall
portions 43 and 44. Wall 48, which is joined to wall portion 42, is
vertically between support plate 17 and plate portion 46a, extends
from partition 29 to wall portion 44 and preferrably is inclined
downwardly in a direction toward wall portions 43, 44 whereby any
fluid draining onto said wall will drain onto plate portion
46a.
Partition 29 is joined to plate 46, wall portion 43 and the
adjacent edge of wall 50, and is horizontally spaced from walls 11,
12 to be directly below partition 21. Although partition 29 does
not extend up to the level of partition 21, it may, or could be
formed integral therewith.
Passageway 49 opens through an opening 53 formed by partition 29,
plate 46 and wall portion 56 to place the passageway in fluid
communication with the venous reservoir 41. The venous passageway
includes side wall portion 56 that is a part of wall 13 and a
bottom wall 46c that is integrally joined to plate portion 46a to
form a continuation thereof. Thus walls 48, 50, 56 and 46c form a
passageway that is closed other than for opening 53 and a drain
aperture 58 that is located in the portion 46c adjacent wall 11,
the end of the passageway opposite opening 53 being closed by a
portion of wall 11. The drain aperture 58 opens through the top
wall of the flowmeter tank, generally designated 63, which is
formed by parts of plate portions 46a, 46c (see FIGS. 3 and 6).
Tank 63 has a side wall 66, a side wall 65, bottom wall 64, an end
wall 67, and an end wall 68. Wall 68 could be formed by extending
wall 11 further downwardly and wall 65 could be formed by part of
wall 13. Drain aperture 51 drains through the top wall of a second
flowmeter tank 74 which is formed by plate 46, tank 74 including
side walls 65, 66, a bottom wall 64, and end walls 67, 68. Thus the
tanks 63, 74 are located within the confines of walls 11-14 of the
cassette or the downward extension thereof, the end walls 67 of the
tanks being located substantially more closely adjacent the wall 11
then the horizontally spacing of the partition 21 from wall 11. A
plurality of vertically spaced indicia (not shown) are provided on
the walls 68 of the tanks to indicate the volume of fluid contained
in the respective tank.
One end of a flexible plastic tube 80 opens through the lower part
of walls 66 to the interior of tank 63 while the one end of a tube
81 opens through wall 66 of tank 74, the opposite ends of tubes 80,
81 opening to the adjacent end portions of a T-coupling 82. Tubes
80, 81 are of sufficient flexibility that they may be readily
clamped to block fluid flow therethrough when a flow rate
measurement is to be taken. With the indicia provided on the tanks
and the blocking of the respective tube 80, 81, the rate of flow
into the respective tank can be determined by using a
stopwatch.
A plastic tube 83 fluidly connects coupling 82 to the inlet 45a of
a generally rectangular, generally flat, static membrane oxygenator
45 which is inclined downwardly in a direction toward wall 12 to
have plasma flow therethrough by gravity flow. The outlet 45b of
the membrane oxygenator (end adjacent wall 12) is fluidly connected
to a conduit 84.
The oxygenator 45 has a top membrane wall 45c and a bottom membrane
wall that are joined to edge members 45d. A reversely bent filter
179 is provided between the top and bottom membrane walls and has
edges joined to edge member 45e whereby liquid entering port 45a
has to flow through the filter prior to flowing through outlet port
45b. The filter is made of nylon or silk fabric of a mesh to filter
out particulate particles in the liquid flowing through the
oxygenator.
Located beneath the flowmeter tanks is an inclined planar plate 88
which is joined to the side walls to extend substantially the
length thereof and is inclined downwardly in a direction from wall
11 toward wall 12 to provide the bottom of an oxygenator chamber
90. The top of chamber 90 is formed by wall 46, and the sides of
the chamber are formed by wall portions 92, 93 of walls 13, 14. In
this connection it is to be noted that inclined plate 88 is spaced
from and is in part directly beneath the flowmeter tanks.
A mounting member, generally designated 97, is provided for
supporting the oxygenator membrane in a generally planar condition,
member 97 having a bottom plate 98 that is slidably positioned on
plate 88, an upstanding wall portion 91 joined to one end portion
of plate 98 and an opposite upstanding wall portion 94 joined the
opposite edge portion of plate 98. In a normal operating position,
wall 94 forms one end of the oxygenator chamber and wall 91 the
opposite end whereby the oxygenator chamber is closed other than
for the gas discharge ports 95 in wall 94, the wall portion of wall
94 that defines a close fluid fit with the duct 83 that extends
therethrough, and the wall portions of wall 91 that form a close
fluid fit with the conduits 84 and 96 which extend therethrough. In
the normal operating condition, wall 91 forms an openable portion
of wall 12, i.e., located directly below wall portion 26 while wall
94 is horizontally between the tank walls and wall 91, spaced from
the tank walls, and substantially more closely adjacent the tank
walls than wall 91.
Referring in particular to FIGS. 6 and 8, adjacent each side of
plate 98 and joined thereto is an upright flange 99 that mounts a
plurality of horizontal bolts 100 which in turn are threaded into a
longitudinal bar 101, each bar being between flanges 99 and closely
adjacent the respective flange. Bars 101, which are parallel to
flanges 99 and spaced therefrom, mount a plurality of upright pins
102 that are extended through apertures in the adjacent side edge
portion of the oxygenator that is above the bar to support the
oxygenator in a generally flat condition vertically between plates
98, 46. Bolts 100 may be rotated to varying the spacing of bars 101
and thereby the tautness in a side to side direction of the
membrane oxygenator. The discharge end of conduit 96 is preferrably
bifurcated with one leg discharging beneath the oxygenator and the
other leg above whereby the discharged gas can flow both above and
below the oxygenator to wall 94.
It is to be understood that the structure for mounting the
oxygenator may be varied. For example the plate 98, bars 99 and
bolts 100 may be dispensed with. In such a case the wall 94 is
joined to plate 88 and/or the side walls 13, 14; wall 91 integrally
joined to wall portions 26, 105; and bars 101 secured to plate 98
to mount the oxygenator in spaced relationship to plate 98.
Referring in particular to FIGS. 6 and 7 located vertically below
the discharge end portion of the membrane 45 is an arterial
reservoir, generally designated 104, that other than set forth
below is enclosed by wall portion 105 of wall 12, a bottom wall
106, an end wall 107 opposite wall portion 105, side wall portions
108, 109 of walls 13, 14 respectively and portion 88a of plate 88.
Conduit 84 has an outlet port opening through wall portion 105 to
the interior of the arterial reservoir while wall portion 106 in
the lower part thereof has a discharge port 107a fluidly connected
by a conduit 110 to one end of an elongated flexible pump tube 112.
A bar 111 secured to wall 13 acts in combination therewith to
provide a fluid passageway 111a that opens to the top of the
arterial reservoir and to chamber 20 to maintain the same pressure
in each.
Located in the pump tube are spaced, one-way valves 113, the valves
advantageously being of the construction described in U.S. Pat. No.
3,525,356. The opposite end of the pump tube is fluidly connected
to a transverse tube 115 that in turn opens to the inlet end of the
heat exchange coil 117 of the heat exchanger generally designated
118. Coil 117 is coiled about a large diameter tube 122 that is
located within the heat exchanger housing 119 and joined to one end
wall 119a thereof to be supported in spaced relationship to the
remaining walls of housing 119. The heat exchanger housing has a
right angle bracket 116 secured thereto that in cooperation with
the U-shaped bracket 114 secured to wall 13 removably mounts the
heat exchanger adjacent wall 13 to extend beneath the oxygenator
chamber. That is bracket 116 has a horizontal leg extended through
the opening formed by bracket 114 and wall 13 to be supported by
said bracket while permitting horizontal removal of the housing in
one direction.
The heat exchanger includes an inlet port 121 that opens through
wall 119a to the interior of tube 122 adjacent wall 119a and an
outlet tube 120 that extends through wall 119a to terminate
adjacent wall 119b and open to the space between tube 122 and the
housing 119. The inlet port 121 is connectable to a suitable source
of cooling fluid under pressure whereby the cooling fluid is forced
through the housing in contact with the cooling coil to the outlet
port 120.
The end of the cooling coil 117 remote from its inlet is fluidly
connected by a conduit 124 that extends transversely from housing
119 and through sidewall 14 to have an outlet port that is fluidly
connected to the lower end of the conduit 125. The upper end of the
conduit 125 is fluidly connected to the inlet port in the bottom
wall of the bubble trap generally designated 127 that is mounted on
the exterior surface of wall 14. One ends of conduits 128, 129 are
connected to outlet ports in the lower parts of the opposite end
walls of the bubble trap. The opposite ends of the conduits 128,
129 extend through wall portion 22, of wall 14 to extend into
chambers 19, 20 respectively for conducting plasma under pressure
into kidneys 126 placed in the respective chamber.
Suitable divider walls 136 are provided in the lower portion of the
bubble chamber to prevent direct flow of fluid from the inlet port
of the chamber to the discharge ports thereof, whereby air in the
liquid flowing into the bubble chamber is separated out of the
liquid, i.e. flows into the space in the bubble chamber above the
liquid in the chamber. A metal sheath 137 extends into the bubble
chamber, the sheath being of a shape to have the probe (not shown)
of a temperature sensor mounted therein for continuously indicating
the temperature of the liquid in the bubble chamber. Further, a
pressure sensor tube 138 is in part mounted by the bubble chamber,
one end of tube 138 being adapted for connection to a pressure
sensor for continuously providing a pressure reading of the
pressure in the chamber and the other end being located in the
bubble chamber adjacent the top of the chamber to be located
substantially above the normal level of liquid in the chamber.
At a location exterior of the chamber tube 138 extends through a
sample port member generally designated 141 (see FIG. 9). Member
141 includes a block 139 through which the tube extends, block 139
having a bore 139a that at one end opens to the ambient atmosphere
and at the opposite end opens through an aperture in the tube to
the interior of the tube (or the tube 138 could be two separate
tube portions having adjacent ends mounted in block 139 in spaced
relation). A Silicone rubber plug 140 is mounted in the bore 139a
in compression to block fluid flow from the tube through said bore,
but at the same time permit a syringe needle being extended through
the plug whereby the contents of the syringe can be injected into
the tube, or fluid in the tube can be withdrawn. Due to the plug
being mounted in compression, upon withdrawing the needle, the plug
material expands to close the opening made by the needle when it
was extended through the plug.
As an example of an advantage of providing port member 141, in the
event the liquid level in the bubble chamber drops beneath (or is
below) a level desired, a syringe needle may be extended through
plug 140 to withdraw air from conduit 138 and thereby reduce the
gas volume in the chamber; or if the liquid level is too high, the
syringe may be used to inject air into the tube and thereby
increase the volume of gas above the liquid in the chamber.
A sample port member, generally designated 142, of the same
construction as member 141, is mounted by conduit 125 at a location
exterior of the cassette and the bubble chamber in the same manner
member 141 is mounted by conduit 139. By inserting a syringe needle
through the plug of member 142, a sample of the perfusate may be
withdrawn from conduit 125, or if an injectable drug is contained
in the syringe, the drug may be injected into the conduit 125.
Advantageously the joints 96a, 125a, 128a, 129a of the conduits 96,
125, 128, 129 respectively may each have a bore opening to the
fluid passageway of the respective conduit and a plug of silicone
rubber in the bore whereby a liquid or fluid may be withdrawn from,
or injected into the respective passageway.
The cassette of this invention is used in conjunction with a
transport module, generally designated 145 (see FIG. 1), or an
in-hospital support module (see FIG. 11). The transport module is
of the size that may be manually carried and includes a main body
146 to which there is removably secured a cover 147 that may be
locked in a closed position by lock mechanism 148. Within the main
body there is mounted a battery-motor driven pump 150 which has an
elongated plate 151 and an adjustable, stationary plate 152 forming
a pump chamber to have the pump tube extended therebetween when the
cassette is mounted on the main body 146 in position of use. The
plate 151 is cam driven, and through conventional adjustment
mechanism, the stroke thereof is adjustable to control the
prefusion pressure.
Further, within the main body 146 there is mounted a reservoir 155
for containing ice water, a battery operated, motor driven pump 156
for pumping the ice water from the reservoir through conduit 164 to
the heat exchange cooling fluid inlet 121 and a return tube 157 for
conducting fluid from the heat exchange cooling fluid outlet to the
reservoir. The motors for the pumps through appropriate electrical
components (not shown) are optionally powered from a power cord
connectable to a conventional AC power source, for example an
electrical 110V socket in a building. Additionally within the main
body there is provided a chamber for containing a cylinder 160 of a
mixture of oxygen and carbon dioxide (preferrably about 80% oxygen
and 20% carbon dioxide), and conduits and a valve (not shown) for
fluidly connecting the cylinder to the gas inlet conduit 96 of the
cassette and controlling the rate of flow thereof. The main body
has a control panel 170 with control elements for the pumps, and
gas flow, and pressure and temperature guages, and a closure 171
that may be opened when the cover is latched in place on the main
body there being provided latch mechanism (not shown) for
releasably retaining closure 171 in a closed position.
The cassette is removably held in place on the main body by, for
example, brackets 154 secured to the module frame, and the brackets
being secured to the cassette by screws 153 extended through the
brackets and threaded into the cassette walls to removably clamp
the cassette to the main body. With the cover 147 open, the
cassette may be readily detached from brackets 152, the couplings
for the cooling fluid, oxygen and carbon dioxide mixture, and the
pressure and temperature sensors disengaged and then the cassette
lifted.
The cassette may be then readily positioned on the top wall 181 of
an in-hospital support console, generally designated 180, that is
provided with motor driven pulsating pump 182 of the same
construction as pump 150, pump 182 having elongated plates
extending above the top wall to form a pump chamber to receive the
pump head of the cassette. Brackets are provided on the top wall
for clamping the cassette thereto. Also console 180 has an
electrically operated refrigeration unit 183 having lines 184, 185
that are adapted for connection to lines 120, 121 of the heat
exchanger for supplying and circulating cooling media through the
exchanger. Also within the console are carbon dioxide and oxygen
cylinders 188, 187 that are connected through lines 189, 190 to a
line 191 that is adapted for easy connection to line 96. Within
lines 189, 190 there are provided shut off-flow control valves 192,
193 respectively. Additionally the console includes temperature and
pressure sensors and gauges, controls for automatically controlling
the operation of the refrigeration system to maintain the perfusate
within the desired temperature range, and controls for the
pulsatile pump.
On being placed on the support console, the cassette is clamped in
place and the connections made for conducting the cooling fluid
between the refrigeration unit and the heat exchanger inlet and
outlet, carbon dioxide and oxygen under pressure from lines 192,
193 to conduit 96, and the pump head placed in position between the
stationary and cam driven plate of the support console, i.e. the
pump head 112 placed in the pump chamber. A rectangular cutout 163
is provided in wall 14 to facilitate placing the pump tube in the
pump chamber. The support console is of much larger size than the
transport unit and is of the construction to be used in the
hospital.
In using the cassette when in place with either transport console
145 or a support console, the appropriate fluid connections made,
including a cannula connected to conduit 128 and inserted in a
blood vessel of the kidney 126, and the pumps operating to
pressurize plasma in the bubble trap, the perfusate (plasma) is
perfused through the kidney in chamber 19, flows through the
apertures 36 into the venous reservoir 40, and under gravity flow,
flows along plate portion 46a to drain through the aperture 51 into
the flowmeter tank 74. Likewise, as to a kidney placed in chamber
20, the plasma flows under pressure through conduit 129 and is
perfused through the kidney, drains through the drain apertures 37
to the venous chamber therebeneath and thence along plate portion
46b to the inlet 53, and therethrough to flow through the
passageway 49 to drain through the aperture 58 into the flowmeter
tank 63.
Assuming that neither of tubes 80, 81 are clamped off, the plasma
in tanks 63, 74 flows through said tubes to and through tube 83 to
the inlet of the membrane oxygenator. It is to be noted that a
proper mixture of carbon dioxide and oxygen under pressure is
discharged by conduit 96 into the oxygenator chamber and
subsequently through the discharge openings 95 in wall 94. Since
the membrane oxygenator is suspended in the oxygenator chamber, the
gas mixture in the chamber flows in contact with the top and bottom
surface of the oxygenator in a direction generally opposite to the
direction of flow of fluid through the oxygenator. As a result the
plasma in passing through the oxygenator gives off carbon dioxide
and takes on oxygen. The plasma in flowing through the oxygenator
under gravity flow, flows to conduit 84 and thence into the
arterial reservoir 104. From the arterial reservoir, plasma is
drawn into the pump tube 112 and thence pumped under pressure
through the cooling coil, the rate of flow of cooling fluid through
the heat exchanger being such to maintain the plasma exiting from
the cooling coil at the desired temperature. From the cooling coil,
the plasma is forced under pressure through conduit 124 and conduit
125 into the bottom of the bubble chamber. The pressure of the
plasma in the bubble trap is controlled by controlling the stroke
volume of the pump. Thus, the plasma in the chamber is forced under
pressure through the conduits 128, 129. One of the conduits 128,
129 is clamped to block fluid flow from the bubble trap through the
conduit that extends into the respective chamber 19, 20 in which no
kidney is located.
It is to be noted that with this invention, the cooling coil,
arterial reservoir, oxygenator membrane, flowmeter tanks, venous
reservoir, and organ receiving chambers are in a self-contained
unit. Further, from the time the liquid (perfusate) passes through
the kidney until it flows into the arterial reservoir, the flow is
gravity flow. Additionally, the overall size of the cassette is
reduced in view of the general zigzag plasma flow path. That is,
the plasma perfused through the kidney generally flows in a
direction toward the end wall 11, then downwardly into the
respective flowmeter tank, thence flows through the oxygenator
membrane generally in a direction toward end wall 12 thence
downwardly into the arterial reservoir, thereafter from the
arterial reservoir it flows generally in a direction toward the
downward extension of wall 11 to a location adjacent such downward
extension, and then transversely to the inlet of the cooling coil.
Thereafter it flows generally in the direction toward end wall 12
to the outlet of the cooling coil and thence upwardly to the bubble
trap. It is to be noted that advantageously the bubble trap is
located about midway between the walls 11 and 12. Even though this
invention has been described with reference to perfusion of
kidneys, it is to be understood that by using appropriate sized
cassettes it can be used for perfusion of livers and hearts, or
other organs of a body.
As one example of the cassette of this invention that is suitable
for perfusing kidney weight up to 600 grams with effective
oxygenation up to 600 ml./min. plasma flow, the height of the
cassette from the top of closure 27 to the bottom edge of wall 13
is nearly 10 inches, the length dimension between the exterior
surfaces of walls 11, 12 is approximately 121/4 inches and the
width dimension between the exterior surfaces of walls 13, 14 is
approximately 71/2 inches. A transport module of the type
illustrated in FIG. 1, including gas cylinder, cooling liquid and
other elements thereof together with a cassette weighs about 80
pounds; and can be used to keep kidneys alive up to about 12 hours
without recharging the batteries, provided the supply of ice is
maintained; and with changing the gas cylinder, replenishing the
ice supply and maintaining the source of power for about 48 hours.
When the cassette is used with an in-hospital support console, it
can keep a kidney alive for about 48 hours.
The walls 11-14 and the other walls and plates forming the various
chamber, tanks and reservoirs, the heat exchanger housing and
closure 27 are preferrably made of a plastic material such as
plexiglass.
Further, advantageously all other members of the cassette, other
than the bolts 100 and pins 102 are made of plastic.
The transport module can be powered by batteries, a car or aircraft
electrical system or the electrical system of a building. Further,
it is small enough to fit in an airplane seat, and can be manually
carried, for example, one model with the cassette therein weighs
about 80 pounds. Thus the transport module may be readily
transported to a donor organ site, have the donor organ placed in
the cassette circulatory system and the module controls operated to
keep the organ viable and then transported to a remote transplant
site where the cassette is removed from the transport module. At
the transplant site the cassette is clamped on the in-hospital
support unit and connected to the unit sources of gases and cooling
fluid and the unit pump actuated to pump plasma through the kidney
or other organ without removing the organ from the cassette.
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