U.S. patent number 3,731,680 [Application Number 05/191,307] was granted by the patent office on 1973-05-08 for pressure regulating controller.
Invention is credited to Thomas S. Hargest, Floyd A. Wright.
United States Patent |
3,731,680 |
Wright , et al. |
May 8, 1973 |
PRESSURE REGULATING CONTROLLER
Abstract
The invention disclosed is for a pressure monitor and control
device having particular utility in medical technology were
constant monitor of hydro-static pressure is required. The
disclosed device is especially useful in a method for effecting
extra-corporeal hemodialysis.
Inventors: |
Wright; Floyd A. (Charleston,
SC), Hargest; Thomas S. (Charleston, SC) |
Family
ID: |
22704961 |
Appl.
No.: |
05/191,307 |
Filed: |
October 21, 1971 |
Current U.S.
Class: |
604/6.06;
128/DIG.3; 210/109; 210/646; 210/90; 210/137; 604/118 |
Current CPC
Class: |
A61M
1/14 (20130101); A61M 1/3639 (20130101); Y10S
128/03 (20130101) |
Current International
Class: |
A61M
1/36 (20060101); B01d 031/00 (); B01d 013/00 ();
A61b 019/00 (); A61b 005/02 () |
Field of
Search: |
;128/DIG.12,13,214E,214B,214F,214R,218A ;210/90,321,22 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Medbery; Aldrich F.
Claims
What is claimed is:
1. In a method for extra-corporeal hemodialysis wherein blood is
pumped through venous tubing from a patient into a dialysis
assembly having means for effecting dialysis of waste materials
from the blood and into a dialysis fluid flowing through the
dialysis assembly, with further means for passing dialyzed blood
through a debubbler prior to return through a venous tubing to the
patient, the improvement which comprises:
A. providing a pressure indicating means for the debubbler;
B. generating a signal responsive to the pressure in the
debubbler;
C. monitoring the indicated pressure signal of the debubbler;
D. amplifying said signal;
E. applying clamping pressure on the venous tubing in response to a
falling pressure signal from the debubbler to provide an increase
of pressure in the venous tubing;
F. removing clamping pressure on the venous tubing in response to
an increasing pressure signal from the debubbler;
G. actuating a pump disabling and terminating means upon a zero
signal from said pressure indicating means; and
H. providing an alarm sensor and transmitter for terminating
operation of the pump.
2. The method of claim 1 wherein said monitoring of the pressure of
the debubbler is by a transducer.
3. The method of claim 1 wherein said clamping is effected using an
electromechanical clamp.
4. An electro-mechanical pressure monitor and control system for
controlling the flow of blood through a tube connected to the
circulatory system of a body, during extra-corporeal hemodialysis,
which system comprises in combination, a fluid pressure monitor
means disposed in communication with an electronic amplifier, said
amplifier disposed in further communication with an
electro-mechanical clamp, said clamp having a reversible motor and
a position screw terminated by a relatively movable anvil, said
relatively movable anvil disposed for effecting or removing
clamping pressure on said tubing by being positionable between the
relatively movable anvil and a relatively stationary anvil, said
relative stationary anvil being hand positionable for initial
positioning relative to the said tubing, a debubbler, a venous
tubing connected thereto, and a pump disposed relative to tubing
receiving blood from a patient, said pressure monitor means
disposed relative to the debubbler, means responsive to said
pressure monitor to operate said clamp disposed relative to the
venous tubing to provide a means for which a fall of pressure
sensed at the debubbler results in relative clamping of the venous
tubing and an increase of pressure sensed at the debubbler results
in relative removing of clamping of the venous tubing.
5. The system of claim 4 wherein the pressure monitor means is a
transducer.
6. The system of claim 4 wherein an alarm sensor is in
communication with a warning device and the pressure
transducer.
7. The system of claim 4 wherein warning devices are in
communication with an alarm sensor which further monitors signals
from the means for monitoring the pressure of the debubbler.
Description
This invention relates to a pressure monitor and control device.
More particularly, the present invention provides a pressure
monitor and control device for use in a method for extra-corporeal
hemodialysis for minimizing dangers of equipment malfunction as
well as minimizing attention required by an operator of the
system.
Devices are known to the art for effecting extra-corporeal
hemodialysis. These devices are typically employed as a therapeutic
measure when kidneys no longer perform their blood purifying
function resulting in accumulation of toxic wastes in the blood. In
hemodialysis, blood is made to flow between semipermeable membranes
which permit passage of toxic wastes into a circulating dialysis
solution, while restricting passage of blood. Toxic wastes in the
blood, notably urea, creatinine, uric acid, and other deleterious
products move through the semipermeable membranes because of the
difference in the concentration gradient between that present in
the blood, and that of the dialysis fluid, the latter being
essentially zero.
During extra-corporeal hemodialysis, the operation must be
precisely controlled and monitored as blood moves from its normal
physiological confines to the extra-corporeal environment for
processing.
Typically, prior art dialyzers require constant attention for signs
of blockage or restricted flow and do not provide means for
regulating and monitoring these effects relative to the patient.
Accordingly, the present invention provides means for positive
monitor and control of pressure, with further means for activating
an alarm system in the event pressure varies beyond a
pre-established range.
Generally stated, the present device includes a pressure monitor
means disposed relative to a debubbler in the blood return line of
a dialysis machine. Pressure may be monitored from air vents of the
debubbler, and by means which communicate this pressure monitor
with an electro-mechanical clamp on the venous tube, control of
blood circulation may be maintained. The electro-mechanical clamp
includes a reversible motor connected, if required, through a speed
reduction unit for driving a movable anvil relative to venous
tubing and a stationary anvil.
In the method of operation using the device of the present
invention, a decrease of pressure sensed by the pressure monitor
means effects, through appropriate electrical circuity, a signal to
drive the movable anvil against a venous tube in a tube closing
direction. By effecting a closing pressure or restriction in the
tubing there results a counter increase in the pressure of the
blood in the system. The reverse sequence is effected when the
pressure monitor means senses an increase in pressure of blood in
the dialysis system with resulting opening of the restriction
applied by the movable anvil onto the venous tubing. In the event
of pressure loss, such as by rupture or clogging of the venous
tube, or a loss of electrical power, the pressure monitor means and
the associated electrical circuity causes an alarm to activate
along with effecting disabling of the hemodialysis machine by the
movable anvil and dialysis pump control means.
Referring to the drawings in which like elements are designated
throughout the several views:
FIG. 1 illustrates in block diagram operation of the present
invention;
FIG. 2 illustrates in perspective view the present pressure monitor
and control device in position on a venous tube;
FIG. 3 illustrates diagrammatically the positioning and method of
operation of the present device during extra-corporeal
hemodialysis;
FIG. 4 is a side elevational view of the electromechanical clamp of
the present device taken in partial section;
FIG. 5 is a left side elevational view of the clamp of FIG. 4;
and
FIG. 6 is a right side elevational view of the clamp of FIG. 4.
Referring to FIG. 1, where the general sequence of operation of the
present invention is illustrated, electrical power controlled by a
switch is supplied to the unit. Next, tubing is positioned in the
electro-mechanical clamp described in detail subsequently, and
adjusted to obtain a desired pressure which is read from a gauge.
The unit after being connected to the dialysis machine is ready for
operation. The electronic amplifier responding to signals of
pressure monitored by a transducer taken through a pressure set
point relative to the venous tubing causes the electro-mechanical
clamp to either tighten or release clamping relative to the venous
tubing depending upon whether increase or decrease of pressure is
desired. Should failure of the system result, a signal is provided
from the transducer such as if pressure failure results causing an
alarm to sound or other warning device to activate, as desired.
FIG. 2 illustrates the pressure monitor and control device of the
present invention generally illustrated as portable unit 10 having
control box 12, and electromechanical clamp 14 disposed about
venous tubing 16. Operation of unit 10 in extra-corporeal
hemodialysis is more particularly illustrated in FIG. 3.
In FIG. 3, patient 20 is prepared for extra-corporeal hemodialysis
according to conventional practice. Also, the dialyzer is similarly
prepared such as by effecting prior rinse, sterilization, testing
and the like prior to actual operation. After all the equipment has
passed check-out, hemodialysis begins. Whole blood is received
through tube 22 from the patient by conventional pump 24 suited for
extra-corporeal dialysis such as a peristaltic or roller pump 26.
This blood proceeds through line 28 into conventional dialysis
assembly 30. Correspondingly, dialysis fluid in line 27 is pumped
into assembly 30 from which it is removed with waste substances
through line 29. The composition of dialysis fluid may be changed
in accordance with the therapy required for a particular patient.
Generally, compositions of dialysis fluid are described in
"Hemo-dialysis for Chronic Renal Failure" by Freeman, Maher &
Schreiner in Annals of Internal Medicine, Vol. 62, No. 3, March
1965. A temperature control may be provided, as desired, with
heating means to properly control and maintain the temperature of
the dialysis fluid at a prescribed level.
As blood moves from the radial artery inlet tube 22, it proceeds to
dialysis assembly 30 in between semipermeable layers where dialysis
is effected and out by line 31 to debubbler 32 from line exit 34.
From the debubbler, the blood proceeds through venous line 16 to
the vein of patient 20 by outlet 37. Meanwhile, fresh dialysis
solution under action of suitable pump means is drawn through line
27 and into interstitial compartments of dialysis assembly 30.
Although fresh dialysis solution is indicated as passing through
assembly 30 to outlet 29 in parallel flow to blood passing through
the unit, it is recognized that other flow patterns including
countercurrent flow may be used as desired.
Toxic wastes dialysates such as urea and the like proceed through
line 29 for removal from the unit by conventional practice.
Connected to dialysis assembly 30 is pressure monitor and control
device 10 of the present invention. Electromechanical clamp 14 of
device 10 is positioned on venous tubing 16, with electrical
connection to pump 26 for control of the pumping action in the
event of blockage or zero pressure in the assembly. Pressure
monitor and control device 10 further includes line 36 with
associated pressure reading means attached to debubbler 32.
Pressure of the debubbler is monitored by the reading means
illustrated as a gauge and the signal therefrom is returned to
device 10 for electrical interpretation. Electrical power is
presented into device 10 by outlet 38.
The electro-mechanical clamp 14 is illustrated in greater detail in
FIGS. 4-6. Clamp 14 includes speed reducing gear unit 39 receiving
drive from reversible motor 40. Unit 39 is mounted onto end plate
41. End plate 41 is maintained in relative position from front
plate 43 by spacers 42 and bolts 45.
Through gear unit 39, positioning screw 44 is connected to enter
advance or retract movable anvil 46 relative to a positionable
anvil 48 normally fixed after initially set. For practical purposes
of this invention, anvil 48 is considered as being fixed although
it is recognized that relative movement thereof is possible using
turnable hand set 50 within L-shaped support block 52.
Also illustrated as parts of the electro-mechanical clamp 14 are
block 47 which insures accurate movement of movable anvil 46, and
venous tubing 16 disposed between movable anvil 46 and anvil
48.
In operation of device 10, electro-mechanical clamp 14 is
positioned on venous tube 16 and anvil 48 is moved to establish a
predetermined pressure by clamping against tube 16. The moveable
anvil 46 is then controlled by increasing or decreasing pressure of
tubing 16. This pressure will be determined by the pressure
monitored at debubbler 32. Should the pressure begin to fall within
venous tubing 16, motor 40 will activate moving anvil 46 to
restrict fluid passage within tubing 16 thereby resulting in an
increase of pressure in the system. The converse also results
should an increase in the pressure of the system be sensed through
debubbler 32. In the event the pressure of the system drops to zero
by clogging or the like, a signal is transmitted from device 10
through line 25 to terminate the pumping action of pump 26. In the
latter situation, alarm sensors and warning devices as previously
indicated may be actuated.
The various elements of the present apparatus unless otherwise
indicated may be secured to adjoining elements by any suitable
means such as bolts, welding, rivets or the like. In addition,
auxiliary support of reinforcement members may also be included as
part of the apparatus where required.
Although a preferred embodiment of the invention has been
illustrated herein, it is to be understood that various changes and
modifications may be made in the construction and arrangement of
elements without departing from the spirit and scope of the
invention as defined.
* * * * *