 |
Description  |
|
|
BACKGROUND OF THE INVENTION
1. Field Of The Invention
Cold packing and pressure bandages are both well known medical management
techniques. Cold packing is particularly well suited to the treatment of
bruises, muscle strains, sprains and similar muscle, ligament and joint
dysfunctions while pressure bandages and splints are used to control
hemorrhage, temporarily secure pressure and antiseptic compresses while
inhibiting the contamination of the injured surface by airborn bacteria
and the like.
More conventional cold packing methods like ice bags, wet cloths, etc., can
provide only short periods of relief for a number of reasons. Ice packs
have to be periodically recharged requiring personnel time and the expense
of purchase, transport, storage and replacement of large quantities of
ice. Also, ice bags and wet cold cloths create a very damp cold which,
while more tissue penetrating than dry cold is usually a more painful
procedure to the patient than dry cold. These treatments also tend to
dampen the surrounding area which has obvious contraindications in a
sterile field or surgical theater. Additionally, recent medical advances
in cryogenics and cryotherapy have indicated that lower temperatures than
the operational range of ice packs and baths, usually 35.degree. F. or so,
are needed in some comprehensive medical management regimens. Along with
these findings have come the need to produce ultracold methodology
instrumentation. Additionally, these ultracold treatments have been seen
to be less painful to the patient than damp cold treatments.
Concomitant advances in medical pressure usage techniques have disclosed
the usefulness of intermittent variation in the pressure applied to a
treated area. Traditionally, pressure bandages and splints have been of
extremely simple design and usually able only to exert one fixed pressure.
Any desired change in pressure was manually adjusted. Such adjusted
pressures cannot be established accurately with ordinary procedures. While
this technique of manual pressure variation is acceptable for crisis
treatments, like acute cardiopulmonary or cardiothorasic events, the
continued rotation and adjustment of pressure bandages and the like is not
suited to routine treatment of subacute conditions since it would require
the continuous presence of trained medical personnel.
Recently, chemical cold packs have been introduced. These devices are
simply two or more chemical solutions or substances stored separately in a
packet. Upon need an internal seal is broken, the substance mix and the
reaction produces a strongly endothermic reaction thereby cooling the cold
pack to a single, preset at the manufacture point, low temperature. The
devices are typically used in remote site use, like a paramedical team,
and suffer also from some serious disadvantages in general use. First,
these packs are extraordinarily expensive, have only a one use lifetime,
have a single nonadjustable temperature and exert cold only for a short
period of time.
DESCRIPTION OF THE PRIOR ART
Heretofore, a number of devices and systems have been employed to impose
heat or cold and/or pressure on parts of a mammals. Rinkes et al, U.S.
Pat. No. 2,272,481 of Feb. 10, 1942 discloses a chamber adapted to receive
a limb such as an arm and having liquid input and exit fittings coupled in
a closed system to a reservoir and pump. Liquid is guided in a helical
path around the limb by ribs on the interior of the chamber wall and a
thermostatically controlled heater in the reservoir establishes a
predetermined temperature in the treating liquid. This provides a wet bath
and massage of the limb.
Miller U.S. Pat. No. 2,531,074 of Nov. 21, 1950 discloses an appliance for
a dry massage at a controlled temperature by applying water of controlled
temperature in a controlled sequence at alternately high and low pressures
to a plurality of adjacent chambers of flexible walled material is
suggested that the water can be either heated or cooled.
Chessey U.S. Pat. No. 2,726,658 of Dec. 13, 1955 shows a system including a
coolant control and supply unit and a liquid impervious appliance
receiving the coolant and applicable as a pad to a body portion of a
mammal. It includes a mechanical refrigeration system in the supply unit
controlled thermostatically by the temperature of the coolant which is
maintained in part by intermittent operation of the refrigerator to cool
the coolant in a heat transfer tank containing a heat exchanger. Coolant
is driven through the appliance by a motor which is controlled by a
thermostat responsive to the temperature of the coolant exiting the
appliance.
Gardner U.S. Pat. No. 3,186,404 of June 1, 1965 includes an appliance,
illustrated for human limbs, in the form of a double walled envelope for
limbs which can be filled with fluid to impose pressure on the enclosed
limb. It is suggested that a continuous or intermittent flow of
pressurized air can be passed through the appliance for cooling or for
heating at a selected pressure, the animal part therein.
Pressure can be derived from refrigerant when it is utilized directly in
the appliance as disclosed in Roslonski U.S. Pat. No. 3,871,381 of Mar.
18, 1975 wherein a refrigerant source is coupled to a pad containing
refrigerant passages and a relief valve which bleeds the refrigerant to
atmosphere. Within the limits of the passage geometry and gas pressure of
the expanded refrigerant some pressure is available from such systems
until the supply of refrigerant is exhausted.
Mechanical cooling from a system including a portable mechanical
refrigerator coupled to an evaporation coil in the general shape of the
body portion to be cooled and covered by a flexible jacket or sleeve is
shown in Saunder et al. U.S. Pat. No. 3,916,911 of Nov. 4, 1975. Only
binding pressure is imposed in such arrangements.
An object of this invention is to improve apparatus for constantly or
intermittently applying adjustable pressure to a body part and/or
sustaining an adjustably selected temperature on the part through the
medium of a liquid.
Another object is to combine a whirlpool bath with a temperature controlled
intermittent compression system for the treatment of body parts.
A further object is to facilitate the control of pressure imposed by a
circulating liquid on an appliance for body parts.
SUMMARY OF THE INVENTION
The above objectives are achieved in the present invention by a system for
the medical management of a body portion of a mammal comprising a modular
liquid control station capable of storing, circulating, cooling and
agitating a liquid and controlling the temperature and/or pressure of the
fluid for delivery to an appliance. The liquid is passed through a circuit
to a hydraulic appliance which receives the liquid into an inlet port
freely and allows the forced flow of the liquid through a body, having a
hollow interior cavity. The liquid flow is retarded at the outlet port by
a liquid retardation means of limited liquid porosity, this retardation
means when used in concert with the force applied via the liquid
circulation and pressurization means of the modular control station
results in the precisely controlled pressurization of the hydraulic
appliance. A duty cycle timer allows the programmed intermittent
pressurization of the appliance by operation of a pump for the liquid
while the temperature control system regulates the temperature of the
liquid and thus the hydraulic appliance. The temperature range is
typically maximized at 75.degree.-80.degree. F. with a lower limit well
below the effective operational range of an ice bath, typically on the
order of 35.degree. F.
BRIEF DESCRIPTION OF THE DRAWINGS
Principles and advantages of the invention will be understood from the
following detailed description of an embodiment of the invention as
illustrated by the accompanying drawings, in which:
FIG. 1 is a perspective view of the system of the invention with portions
removed or broken away to reveal interior structure and other interior
structure represented in phantom, only portions of the fluid connections
are shown;
FIG. 2 is a cross section of the storage unit assembly utilized as a
whirlpool bath with the coolant and electrical control circuits shown
schematically;
FIG. 3 is a side view of the hydraulic appliance for receiving the fluid
with portions broken away to reveal construction details; and
FIG. 4 shows a cross sectional view of the flow restrictive outlet of an
appliance.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring initially to FIG. 1, there is shown the general apparatus 20
which includes a modular fluid control station 21 which communicates with
the hydraulic appliance 22 through the liquid communication means 23. The
hydraulic appliance 22 comprises a double walled envelope for liquid which
forms a hollow unitary body 24 with an inlet port 25 integral with the
unitary body 24, an outlet port 26, also integral with the unitary body
24, and securing means 27 to hold the appliance 22 in place on the body
part.
The appliance 22 is connected to the fluid control station 21 through
liquid communications means 23, in the form of flexible hoses including
liquid supply hoses 28 from liquid outlets 29 on station 21 and liquid
return hoses 31 to liquid inlets 32. The ends of hoses can be fitted with
quick disconnect hose couplings which are adapted to mate with the quick
disconnectors on the station 21.
The fluid control station 21 comprises a housing, side cover panels of
which have been removed, built up on a base frame 33 made up of horizontal
side and end beams 34 and 35 and vertical corner and intermediate columns
36 and 37. As seen in FIG. 1, mounted on the sides of the station 21 are
the inlets and outlets 32 and 29 for the liquid to be circulated in the
appliance. The invention is designed to accommodate two appliances 22
simultaneously, there being two inlets 32 and outlets 29 on the station
21.
The housing is closed at the upper edges by a top panel 38 upon which and
through which are mounted various control elements to be discussed in
detail later.
Fluid control station 21 contains a refrigeration system 39, a coolant
reservoir 41, an evaporator coil 42 of system 39 in the bottom of
reservoir 41 and the control and pumping means for the coolant. Externally
accessable controls and indicators appear on the top 38 of the housing for
the station and the inclined panel 43 joining a raise top section 44 with
main top panel 38. Since the control station is arranged to apply coolant
under pressure to the appliance intermittently and at adjustable
controlled pressures and temperatures, top panel 38 displays a temperature
control knob 45, a pressure regulator control knob 46, a timer control
knob 47 and two valve control knobs 48 and 49 for establishing the desired
coolant paths within the coolant circuit. The indicators on the top panel
38 are a main pilot lamp 51, a timer pilot lamp 52, calibrated scales for
the settings of the control knobs for temperature 53, pressure 54 and time
cycle 55. Inclined panel 43 has a temperature gauge 56 and a pressure
gauge 57. Control switches 58 and 59 for the main electrical power supply
and the timer respectively are mounted on the main top panel 38. A
removable cover 61 is provided for an aperture 62 on the raised top panel
section 44 to offer access to the coolant reservoir 41 and enable it to be
used as chilling and/or whirlpool bath for limbs inserted through the
aperture 62 and into the reservoir.
Internally, the control station has its operative elements mounted on the
base frame 33 either directly or on supplemental cross beams or internal
panels mounted on the cross beams or main frame. Many of the elements are
hidden in FIG. 1 and are schematically illustrated in FIG. 2. Cross beams
63 extending between side beams 34 support a panel 64 for the
refrigeration system condenser 65 and motor-compressor 66. Intermediate
columns 37 have a cross beam 67 on which is mounted pump 68 and its motor
69 together with fittings and support clamps for much of the internal
plumbing shown only in schematic form in FIG. 2.
Top panel 38 supports on its under side, so that they are not visible in
FIG. 1, many of the elements shown schematically in FIG. 2. These elements
are supported by threaded couplings around the control shafts connected to
the control knobs in locations below those knobs and by conventional screw
mounted brackets. The elements include temperature controller 71, pressure
regulator 72, timer 73, valves 74 and 75, pilot lamp sockets 76 and 77,
and switch housings 78 and 79.
Stratification of the chilled coolant in reservoir 41 is avoided by
bubbling air through the coolant. Air pump 81 for the bubbler is mounted
in panel 82 secured to intermediate column 37.
Cross beams 80 extending between side beams 34 have angle iron stringers
spanning the space between them to form a cradle for the bottom of
reservoir 41.
Connector fittings between the internal plumbing and the hoses 28 and 31
are mounted on side panels for the station. A sight glass, not shown, can
be provided to indicate the liquid level in reservoir 41 at a side panel
and suitable vents can be provided to afford adequate ambient air
circulation through the condensor 65.
The liquid control station 21 functions in four principal modes of liquid
transfer, a reservoir fill, an appliance fill, a reservoir circulate, and
an appliance circulate mode. It also establishes any temperature selected
in a range for the coolant, a maximum selected pressure within a range for
the appliance, and a duty cycle of time the appliance is subjected to
pressure and a time the appliance is relieved of pressure.
Reservoir 41 typically is a tank of polymeric material such as polyethylene
having an open upper end 83 and suitable fittings 84 and 85 for the
passage through its walls in liquid tight relationship of the refrigerant
tubing 86 between evaporation coils 42 and compressor 66 and condenser 65.
Inlet and exit fittings 87 and 88 on the tank wall and bottom respectively
for the coolant within the tank are coupled to the remainder of the liquid
circuit as by hoses and a fitting 89 for a thermal sensor such as a
thermocouple 91 electrically coupled to temperature controller 71 also
passes through the reservoir wall. Thermal insulation in the form of
sheets 92 which may be polymeric foam are secured around the outer walls
of the reservoir and in the cover 61 and are pierced where the fittings
and fluid conduits to which they are connected pass.
The controls discussed include the main on-off switch 58 which activates
all electrical components by energizing the supply circuits and directly
activates the motor 90 for the air pump and the electrical refrigeration
components including temperature controller 71 and through it the motor
for compressor 66. Pump on-off switch 59 activates the components
associated with pumping liquid through the hydraulic appliance and filling
and draining the tank including dual timer 73 and pump motor 69. Pressure
regulator 72 controls the pressure applied to the appliance. Temperature
control 71 provides an adjustable control of coolant temperature and
maintains that temperature as sensed by thermal sensor which supplys a
control signed on line 93 to control 71. Dual timer 73 controls the "on"
time and "off" time of pump 68 to control the duty cycle of intermittent
pressure imposed on the appliance. Flow control valves 74 and 75 establish
the paths of coolant flow under the impetus of the pump 68.
The liquid circuit can be set up to fill the tank from a suitable container
(not shown). Advantageously an anti-freeze solution is added, typically,
one gallon of anti-freeze for fourteen gallons of water. The mixture is
drawn from the container through a return hose 31 from an appliance by
disconnecting the hose from the appliance and opening the appliance return
valve 94 (this may be a valve in the fitting which opens when the hose 31
is connected), while valve 74 is set to couple suction line 95 to pump 68
and valve 75 is set to couple pump 68 to tank return line 96. Both the
main switch 58 and the timer control switch 59 are closed to couple source
97 through timer 73 to pump motor 69. The refrigeration system is not
needed at this time so the temperature controller 71 should be set high.
Dual timer 73 should be operated with a long on interval, for example 180
seconds "on" and 5 seconds "off" to cause the pump to operate a
preponderance of the time. Coolant thus is pumped from hose 31 through
valve 94 to the control station 21 and within the station passes through
suction line 95, valve 74, pump 68 valve 75, return line 96 to inlet
fitting 87 and into reservoir 41. When the desired level of fluid has been
introduced into the reservoir, the filling can be terminated by opening
switch 58.
After use, the same circuit setting employed to fill the reservoir can be
used to empty the appliance. In this case the return hose 31 or hoses 31,
where two appliances are in use, are coupled to their respective appliance
22.
The coolant is brought to the desired temperature by operating the
refrigeration system and bubbler. Main switch 58 is closed and the desired
temperature setting made on temperature controller 71 so that the
compressor operates until the signal from thermal sensor 91 causes
controller 71 to interrupt the circuit to the compressor-motor 66. The
coolant can then be internally circulated to assure that it is at a
uniform temperature and that temperature can be read on temperature gauge
56 as actuated from thermal probe 98 which is located in the reservoir by
a probe fitting 99 in the wall. Internal circulation of coolant should be
continued until a stable temperature is indicated.
An internal circulation of coolant is set by connecting exit line 101
through valve 74 to pump 68 while valve 75 is connected to return line 96.
Circulation through the appliance 22 involves closing main switch 58 to
supply electrical power and timer control switch 59 while the desired
temperature setting is made on temperature controller 71 and the "on"
interval and "off" interval are set on dual timer 73. Coolant is drawn
from reservoir 41 through fitting 88 and exit line 101 to valve 74
coupling line 101 to pump 68. It is then passed from pump 68 through valve
75 to regulator 72, set to the desired pressure, and thence through feed
valve 102 to supply hose 28. With these settings of valves 74 and 75 a
return path from appliance 22 is through return hose 31 return valve 94,
suction line 95, check valve 103 and return line 96 to fitting 87 and the
tank.
The return circuit is relatively unobstructed and provides only limited
means to develop a back pressure within the appliance. Thus the pressure
in the appliance will not reflect the pressure set at the regulator and
great volumes of coolant will be required to be pumped by pump 68 to
satisfy some higher settings of regulator 72. This deficiency is overcome
by a constriction in the exit from the appliance which is of a nature to
concentrate the pressure drop in the circuit from the regulator to the
reservoir at the appliance exit and thus cause the appliance internal
pressure to closely approximate the setting of the regulator. This enables
appliances of different size and thus having different internal volumes to
be coupled to the fluid control station 21 and to accurately reflect the
regulator pressure settings.
It will be noted that the pressure regulator 72 is only in the liquid
circuit portion including that for circulating coolant through the
appliance or appliances. Thus the remainder of the circuit can be
essentially unconstricted and free flowing for the reservoir fill mode,
the appliance empty mode and the internal circulate mode. The combination
of the pressure regulator and appliance flow constraint at its exit
imposes a back pressure load on the system other than the normal flow
resistance of the liquid circuit elements only when in the appliance
circulate mode and even then the appliance to reservoir return portion of
the liquid circuit is unrestricted and permits the appliance to bleed its
pressure down when the pump is turned off, thereby providing the
intermittent compression with the same fluid providing the thermal
treatment.
In practice it has been found that a pair of appliances for treating human
legs with a liquid having a predetermined temperature and subject to
regular periods of imposed pressure while pump 68 is operating, and
relieved pressure while pump 68 is dormant, can be supplied by about
fifteen gallons of liquid through half inch hose lines, valves, and
fittings by a pump of five gallons per minute capacity. The system is
equally effective for low volume requirements such as an appliance to an
ankle, knee or wrist. Further, the flow in the liquid circuit is
relatively unrestricted except when operated in the mode directing liquid
through the regulator and appliance with its flow impeding constriction.
Portions of the circuit are used for a multiplicity of operating modes.
within the station the circuit includes liquid issuing and receiving
fixtures 29 and 31, a first two way valve 74 to couple alternate liquid
sources to the pump 68 and a second two way valve 75 to couple the pump
output to the reservoir 41 or appliance 22. A first input line to valve
74, reservoir exit line 101, enables liquid to be drawn from the reservoir
for all but the appliance empty mode. A second input line to valve 74, the
suction line 95, draws liquid from the appliance for the appliance empty
mode. All modes pass the liquid through an output line 104 from valve 74
to pump 68. Pump delivery line 105 carries all liquid in all modes to
valve 75. In the appliance fill and circulate modes, liquid is passed from
valve 75 to regulator 72 through a first output line 106. In the internal
circulation and appliance, empty mode liquid is passed from valve 75
through a second output line, line 107 and tank return line 96, to
reservoir 41. Flow from the regulator 72 to issuing fixture 29 is through
line 108 for the appliance fill and circulate modes. A liquid receiving
line 109 from receiving fixture 32 to reservoir 41 has a first portion
109a merged with a portion of suction line 95, a second portion 109b
merged with a portion of tank return line 96 and a third portion 109c
including check valve 103 so that it returns liquid from the appliance to
the reservoir in the appliance circulate mode using portions of lines also
employed in all other modes.
FIGS. 3 and 4 disclose a typical appliance construction. Numerous forms of
appliances are applicable to this system wherein they offer an envelope
for liquid which can be applied to a body portion of a mammal such that
the application of liquid under pressure causes a flexible, liquid
impervious, wall adjacent the body portion to be pressed against that body
portion. In FIG. 3 a boot is shown made up of an outer wall of fabric 111
which is sealed along its margins to an inner wall of fabric 112 to form a
flexible, liquid impervious envelope. The boot is provided with a foot 113
which is closed along its marginal seam 114 along the bottom and over the
toe and instep. The leg region is open along the front and provided with a
number of binders 115 of webbing which can be secured around the leg
region to constrain the appliance against balloning. A single compartment
for pressurized liquid coolant thus encompasses the patient's foot and
leg. Coolant is introduced through the inlet fitting such as a hose
coupling 116 to which supply hose 28 is connected, passes through the
appliance interior and exits at exit fitting 117 which may also be a hose
fitting. In order to develop the internal pressure, a liquid flow
constriction 118 is provided at the exit port 26 communicating with
fitting 117. This constriction is a fiberous pad 120 retained on the inner
face of the wall contiguous to port 26 by a spider 119 which can be of
fabric of the type employed for the walls of the appliance and is bonded
at the ends 121 of the spider legs to those walls. Pad 120 has sufficient
thickness to permit lateral flow of the coolant therethrough and to space
the body portion 122 of the spider 119 from the appliance walls adjacent
port 26. Coolant flows between the legs of the spider and through the pad
to the port 26 and the port is maintained open by the thickness of the pad
even when return hose 31 is under suction for emptying the appliance. The
pad thickness and overlying spider also prevents the opposed wall of the
appliance from collapsing on port 26 to close it.
Pad 120 is formed advantageously of a three dimensional synthetic textile
made by weaving two different fibers along the length of the fabric and
another across the width. One of the longitudinal fibers shrinks more when
temperature-processed than the other to cause the fabric to pucker and
develop a thickness. Polyethylene is a suitable shrinkable fiber and the
other fibers can be polypropylene, nylon or Saran monofilament. In
practice a pad of about three inch diameter is retained within a spider of
about a five inch span having a body portion 122 of about one inch
diameter.
Another aspect of the present system is that it provides a wet temperature
controlled treatment of limbs utilizing the coolant reservoir 41 as the
wet treatment tub. Such use can be made of the system in the internal
circulation mode as well as in the appliance circulation or intermittent
compression-thermal treatment mode. Cover 61 is removed to expose aperture
62 in the raised top section 44 of station 21. A tank cover 123 with
suitable insulating lining for closing the upper end 83 of reservoir is
removed, thereby exposing the coolant free surface.
An arm or leg to be treated can be inserted through open top 83 of
reservoir and immersed in the coolant. Coolant is circulated by the
placement of inlet fitting 87 in the reservoir wall near the free surface
of the coolant and exit fitting 88 at the bottom. It is enhanced by the
bubbler action of air pump 81. Contact by a hand or foot with the
evaporator coils 42, forming the heat exchanger between the refrigerant
and coolant, is avoided by a protective screen 124 secured to the
reservoir walls above the coils 42 and the thermal sensors 91 and 98.
While the described system for temperature and intermittent compression
treatment in a dry appliance and as a temperature and bath treatment has
been described with respect to a cooled liquid system it is to be
appreciated that a heated liquid system might also be used. The invention
lends itself to many varients accordingly it is to be understood that the
disclosure is to be read as illustrative and not in a restrictive sense.
* * * * *
|
|
 |
|
 |
Description |
|
