U.S. patent number 3,888,259 [Application Number 05/390,271] was granted by the patent office on 1975-06-10 for hypothermia system.
Invention is credited to Robert C. Miley.
United States Patent |
3,888,259 |
Miley |
June 10, 1975 |
Hypothermia system
Abstract
A hypothermia system for therapeutic use, particularly in
hospitals, to cool or heat patients, the hypothermia system
including a novel fluid pressure operated impeller driven pump
effective to recirculate heat transfer fluid through a virtually
closed fluid circuit including a hypothermia pad.
Inventors: |
Miley; Robert C. (East Lansing,
MI) |
Family
ID: |
23541805 |
Appl.
No.: |
05/390,271 |
Filed: |
August 21, 1973 |
Current U.S.
Class: |
607/104 |
Current CPC
Class: |
A61F
7/10 (20130101); A61F 7/00 (20130101); A61F
2007/0056 (20130101); A61F 2007/0076 (20130101); A61F
2007/0095 (20130101) |
Current International
Class: |
A61F
7/00 (20060101); A61F 7/10 (20060101); A61f
007/00 () |
Field of
Search: |
;128/400,402,399,254,258
;165/46 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Trapp; Lawrence W.
Attorney, Agent or Firm: McKinnon; Malcolm R.
Claims
What is claimed is:
1. In a hypothermia system, the combination including hypothermia
pad means, fluid heat exchange means, fluid pressure operated
impeller-pump means having an impeller portion and a pump portion
each provided with a fluid inlet and a fluid outlet, a source of
fluid pressure, means for connecting the inlet of said impeller
portion to said source of fluid pressure, and a closed fluid
circuit connecting the outlet of said pump portion to the inlet of
said pump portion through said heat exchange means and said
hypothermia pad means, said source of fluid pressure comprising a
second closed fluid circuit including the outlet of said impeller
portion and second heat exchange means.
2. In a hypothermia system, the combination including hypothermia
pad means, fluid heat exchange means, fluid pressure operated
impeller-pump means having an impeller portion and a pump portion
each provided with a fluid inlet and a fluid outlet, a source of
fluid pressure, means for connecting the inlet of said impeller
portion to said source of fluid pressure, and a closed fluid
circuit connecting the outlet of said pump portion to the inlet of
said pump portion through said heat exchange means and said
hypothermia pad means, said impeller-pump means including a housing
defining an impeller chamber and a pump chamber, a shaft carried by
said housing and extending into said impeller chamber and said pump
chamber, a plurality of impeller blades disposed in said impeller
chamber and fixed to said shaft, and a plurality of pump blades
disposed in said pump chamber and fixed to said shaft.
3. The combination as set forth in claim 2 including a fluid
passage connecting said impeller chamber with said pump
chamber.
4. The combination as set forth in claim 3 wherein said shaft
extends through the fluid passage connecting said impeller chamber
with said pump chamber.
5. In a hypothermia system, the combination including hypothermia
pad means, fluid heat exchange means, fluid pressure operated
impeller-pump means having an impeller portion and a pump portion
each provided with a fluid inlet and a fluid outlet, a source of
fluid pressure, means for connecting the inlet of said impeller
portion to said source of fluid pressure, and a closed fluid
circuit connecting the outlet of said pump portion to the inlet of
said pump portion through said heat exchange means and said
hypothermia pad means, said source of fluid pressure comprising
electric motor driven pump means and convective heat exchange means
disposed in a second closed fluid circuit including the fluid inlet
and the fluid outlet of said impeller portion.
6. The combination as set forth in claim 5 wherein said second
closed fluid circuit includes a fluid reservoir and is vented to
atmosphere.
7. In a hypothermia system, the combination including hypothermia
pad means, fluid heat exchange means, fluid pressure operated
impeller-pump means having an impeller portion and a pump portion
each provided with a fluid inlet and fluid outlet, a source of
fluid pressure, means for connecting the inlet of said impeller
portion to said source of fluid pressure, and a closed fluid
circuit connecting the outlet of said pump portion to the inlet of
said pump portion through said heat exchange means and said
hypothermia pad means, said fluid heat exchange means including a
thermoelectric heating-cooling unit, a D.C. power supply, and means
electrically connecting said power supply to said thermoelectric
heating-cooling unit.
8. In a hypothermia system, the combination including hypothermia
pad means, the thermoelectric heat exchange means, fluid pressure
operated impeller-pump means having an impeller portion and a pump
portion each provided with a fluid inlet and a fluid outlet, a
first fluid circuit connecting the outlet of said pump portion to
the inlet of said pump portion through said thermoelectric heat
exchange means and said hypothermia pad means, fluid pump means,
and a second fluid circuit connecting the outlet of said impeller
portion to the inlet of said impeller portion through said fluid
pump means.
9. The combination as set forth in claim 8 wherein said second
fluid circuit includes convective heat exchange means.
10. The combination as set forth in claim 9 wherein said
impeller-pump means includes a housing defining an impeller chamber
and a pump chamber, a shaft carried by said housing and extending
into said impeller chamber and said pump chamber, a plurality of
impeller blades disposed in said impeller chamber and fixed to said
shaft, and a plurality of pump blades disposed in said pump chamber
and fixed to said shaft.
11. The combination as set forth in claim 10 including a fluid
passage connecting said impeller chamber with said pump
chamber.
12. The combination as set forth in claim 11 wherein said shaft
extends through the fluid passage connecting said impeller chamber
with said pump chamber.
13. The combination as set forth in claim 12 including a D.C. power
supply, and means electrically connecting said power supply to said
thermoelectric heat exchange means.
14. The combination set forth in claim 13 wherein said second fluid
circuit includes a fluid reservoir and is vented to atmosphere.
Description
BRIEF SUMMARY OF THE INVENTION
This invention relates to hypothermia systems and, more
particularly, to an improved hypothermia system particularly
adapted for use to cool or heat patients. Heretofore, various
therapeutic systems have been employed to cool or heat patients,
such prior therapeutic systems including relatively complex fluid
systems incorporating hypothermia pads or the like through which a
heat transfer fluid is circulated by means of pumps usually driven
by electric motors. Such prior systems are relatively complicated
and expensive, subject to excessive heat losses, often difficult to
transport and require complex fluid circuitry which is difficult to
install and maintain.
An object of the present invention is to overcome disadvantages in
prior therapeutic systems of the indicated character and to provide
an improved hypothermia system incorporating improved means for
recirculating heat transfer fluid through a hypothermia pad to cool
or heat patients.
Another object of the invention is to provide an improved
hypothermia system for cooling or heating patients for medical
purposes, which system incorporates improved fluid pressure
operated impeller-pump means effective to recirculate heat transfer
fluid through a virtually closed fluid circuit including a
hypothermia pad.
Another object of the invention is to provide an improved fluid
pressure operated impeller-pump particularly adapted for use in
hypothermia systems.
Another object of the invention is to provide an improved
hypothermia system that is relatively simple in construction,
economical and commercially feasible to manufacture, assemble and
maintain, durable, efficient, reliable and quiet in operation and
suited for explosion proof environments such as operating room or
oxygen enriched atmospheres.
The above as well as other objects and advantages of the present
invention will become apparent from the following description, the
appended claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a portable hypothermia system
embodying the present invention;
FIG. 2 is a schematic view, with portions broken away, of the
hypothermia system illustrated in FIG. 1; and
FIG. 3 is a sectional, elevational view of a fluid pressure
operated impeller-pump embodying the present invention, showing the
same installed in the hypothermia system illustrated in FIGS. 1 and
2.
DETAILED DESCRIPTION
Referring to the drawings, a hypothermia system, generally
designated 10, is illustrated embodying the present invention, the
hypothermia system 10 being adapted for use, particularly in
hospitals, to cool or heat patients for medical purposes. In the
preferred embodiment of the invention illustrated, the hypothermia
system 10 includes a conventional hypothermia pad 12 through which
a heat transfer fluid, such as water, is circulated to cool or heat
patients who have been placed in contact with or wrapped in the pad
12. The hypothermia system 10 also includes a fluid pressure
operated impeller-pump, generally designated 14, which will
described hereinafter in greater detail, and a conventional
thermo-electric heating-cooling unit, generally designated 16,
effective to cool or heat water or other fluid circulating through
the hypothermia pad 12. The hypothermia system also includes a D.C.
power supply 18, an electric motor driven pump 20, a fluid
reservoir 22 and a convective heat exchanger 24. As illustrated in
FIG. 1, the fluid pressure operated impeller-pump 14 and the
thermoelectric heating-cooling unit 16 are preferably mounted in a
removable compartment 26 carried by a base compartment 28 mounted
on casters 30. The D.C. power supply 18, electric motor driven pump
20, fluid reservoir 22 and convective heat exchanger 24 are
preferably mounted in the base compartment 28 although it will be
understood that, if desired, the power supply 18, pump 20,
reservoir 22 and heat exchanger 24 may be permanently installed in
a convenient location.
In the embodiment of the invention illustrated, the empeller-pump
14 is comprised of a housing 32 defining an upper impeller portion
34 and a lower pump portion 36 disposed below the impeller portion
34, the impeller portion 34 including a fluid inlet 38 and a fluid
outlet 40 while the pump portion includes a fluid inlet 42 and a
fluid outlet 44. A plurality of conventional curved impeller blades
46 are provided which are disposed in an impeller chamber 48
defined by the upper impeller portion 34 of the housing 32, and a
plurality of conventional curved pump blades 50 are provided which
are disposed in the pump chamber 52 defined by the lower pump
portion 36 of the housing 32. The impeller blades 46 and the pump
blades 50 are mounted on a common shaft extending through a
passageway 56 defined by the central portion 58 of the housing 32.
The lower end of the shaft 54 is supported by a bearing 60 carried
by the lower end wall 62 of the housing 32 while the upper end of
the shaft 54 is supported by a bearing 64 carried by a spider 66
having circumferentially spaced, angularly disposed legs 68 fixed
to the wall portion 70 of the housing defining the outlet 40.
In the illustrated embodiment of the invention, the inlet 38 of the
impeller portion 34 is connected to a source of pressurized water,
such as the outlet 72 of the heat exchanger 24, by a conduit or
hose 74, one side 75 of the thermoelectric heating-cooling unit 16
being interposed between the hose 74 and the inlet 38 of the
impeller portion 34. The outlet 40 of the impeller portion 34 is
connected to the inlet 76 of the reservoir 22 by a conduit or hose
78, while the outlet 80 of the reservoir 22 is connected to the
inlet 82 of the pump 20 by a conduit 84, the outlet 86 of the pump
being connected to the inlet 88 of the heat exchanger 24 by a
conduit 90.
In the embodiment of the invention illustrated, the outlet 44 of
the pump portion 36 is connected to the inlet 92 of the hypothermia
pad 12 by a conduit or hose 94, the other side 96 of the
thermoelectric heating-cooling unit 16 being interposed between the
outlet 44 of the pump portion 36 and the inlet 92 of the
hypothermia pad 12. The outlet 98 of the hypothermia pad 12 is
connected to the inlet 42 of the pump portion 36 by a conduit or
hose 100.
The thermoelectric heating-cooling unit 16 is a conventional low
current, D.C. module which may be obtained, for example, from
Materials Electronic Products Corporation, Trenton, N.J. 08638, the
thermoelectric material 101 being comprised of a quaternary alloy
of bismuth, tellurium, selenium, and antimony with small amounts of
suitable dopents, processed to produce an oriented polycrystalline
ingot with anisotropic thermoelectric properties. The
thermoelectric material 101 of the unit 16 is connected to the D.C.
power supply 18 by conductors 102 and 104. Depending upon the
direction of flow of the D.C. current, one side of the unit 16,
such as the side 75, becomes hot when D.C. current is applied to
the thermoelectric material of the unit 16 while at the same time
the other side 96 of the thermoelectric unit becomes cold. When the
flow of D.C. current is reversed, the side 75 becomes cold while
the side 96 becomes hot as will be readily understood by those
skilled in the art.
The connective heat exchanger 24 may, for example, be of the type
conventionally utilized as an evaporator in household or commercial
refrigerators and is preferably formed with flat, smooth exterior
surfaces and built in coils, the exterior surfaces thus being
devoid of fins (which would tend to collect dirt, dust, bacteria
and other foreign materials). With such a construction, the heat
exchanger 24 may be easily cleaned and sterilized and since forced
air cooling and fins are not utilized, the heat exchanger may be
easily maintained in a sterile condition by hospital personnel. The
heat exchanger 24 as well as the power supply 18 are preferably
mounted in the lower compartment 28 and may be disposed at a
position remote from the patient when the hypothermia system is in
use while the removable compartment 26 containing the
heating-cooling unit 16 and the impeller-pump 14 are disposed near
the patient. As shown in FIG. 1 of the drawings, the fluid conduits
74 and 78 and the electrical conduits 102 and 104 are preferably
mounted on a drum 105 secured to the lower unit whereby the fluid
conduits 74 and 78, the electrical conduits 102 and 104 and the
removable compartment 26 may be extended from the base unit 28 when
the system is in use and retracted when the system is not in
use.
In the operation of the hypothermia system 10, assuming that it is
desired to cool a patient who has previously been placed in contact
with the pad 12, and further assuming that the system is
substantially filled with a heat exchange fluid such as water, the
D.C. power supply 18 and the pump 20 are first energized. The
current flowing through the thermoelectric heating-cooling unit 16
then causes the side 75 to become warm and the side 96 to become
cold. At the same time, pressurized water flows from the outlet 86
of the pump 20, through the conduit 90, the heat exchange unit 24
and through the pipe 74 and the warm side 75 of the thermoelectric
cooling unit 16 to the inlet 38 of the impeller portion 34. The
incoming pressurized water then flows through the chamber 48, down
through the passageway 56 surrounding the shaft 54 and through the
pump chamber 52 to the outlet 44. The incoming pressurized water
then flows through the cool side 96 of the thermoelectric cooling
unit 16, which cools the water, and through the pipe or hose 94 to
the inlet 92 of the hypothermia pad 12 so as to cool the patient.
The water flows through the outlet 98 of the hypothermia pad 12,
through the hose 100 to the inlet 42 of the pump portion 36 of the
impeller-pump 14. Any air entrained in the system is vented through
the passageway 56 and out through the outlet 40 of the impeller
portion 34, such air subsequently being vented to the atmosphere
from the open vent 106 in the reservoir 22. As soon as the system
is completely full of water and all air has been evacuated from the
system through the outlet 40 of the impeller portion 34, rotation
of the impeller blades 46 is effected by virtue of the pressurized
water entering through the inlet 38, impinging upon the impeller
blades 46, and then flowing out through the outlet 40 of the
impeller portion. Rotation of the impeller blades 46 effects
rotation of the pump blades 50, carried by the common shaft 54, to
pressurize the water in the pump chamber 52 at a somewhat lower
pressure than the pressure of the incoming water at the inlet 38 of
the impeller, and the pump portion consequently initiates
circulation of cool water from the outlet 44, through the cool side
96 of the thermoelectric unit 16, through the hypothermia pad 12,
and back to the inlet 42 of the pump portion 36. Such a system
permits a virtual closed circuit loop for recirculation of cool
water through the hypothermia pad 12 so as to increase the
efficiency but allows communication with a remote pressurized water
source. The lack of a substantial pressure differential between the
chambers 48 and 52 prevents substantial mixing of the incoming
pressurized water with the cool recirculating water with the result
that substantial isolation of the two fluid loops is
established.
When it is desired to heat the patient, the flow of D.C. current
from the power supply 18 is reversed so that the side 75 of the
thermoelectric unit 16 becomes cool while the side 96 becomes hot.
Water emanating from the heat exchange unit 24 then flows through
the system in the manner previously described whereby heated water
flows through the hypothermia pad 12 to heat the patient while
relatively cool water flows through the impeller pump portion 14 as
previously described. The heat exchange unit 24 thus serves to cool
the recirculating water when the system is utilized to cool a
patient and the heat exchange unit 24 serves to raise the
temperature of the water circulating through the impeller-pump unit
14 when the hypothermia system is utilized to heat a patient.
From the foregoing description, it will be appreciated that the
upper removable compartment 26 may be conveniently disposed at the
bedside of the patient, the impeller-pump portion and the
thermoelectric unit 16 being disposed in such compartment and
operating with relatively little noise while the base unit 28 may
be disposed at a distance remote from the patient whereby any noise
emanating from the pump 20 will be muted so that the patient is not
unduly disturbed. At the same time, since the thermoelectric unit
16, in use, is situated relatively close to the patient, heat
losses between the thermoelectric unit 16 and the hypothermia pad
12 through the hoses 94 and 100 are reduced to a minimum.
Moreoever, no additional spark insulation is required, with the
result that the hypothermia system is eminently suited for
explosion proof environments such as operating rooms and oxygen
enriched atmospheres.
While a preferred embodiment of the invention has been illustrated
and described, it will be understood that various changes and
modification may be made without departing from the spirit of the
invention.
* * * * *