U.S. patent number 3,848,592 [Application Number 05/348,509] was granted by the patent office on 1974-11-19 for single needle alternating flow blood pump system.
Invention is credited to Charles B. Willock.
United States Patent |
3,848,592 |
Willock |
November 19, 1974 |
SINGLE NEEDLE ALTERNATING FLOW BLOOD PUMP SYSTEM
Abstract
A blood pump system, typically employed in dialysis, includes a
blood pump for withdrawing blood via a single hypodermic needle and
valve means operated in synchronism therewith for returning treated
blood via the same hypodermic needle. The operation of the blood
pump is cyclically interrupted and the valve means opened for the
alternate withdrawal and return of blood.
Inventors: |
Willock; Charles B. (Milwaukie,
OR) |
Family
ID: |
23368330 |
Appl.
No.: |
05/348,509 |
Filed: |
April 6, 1973 |
Current U.S.
Class: |
604/6.05;
128/DIG.12; 604/30; 604/153; 417/477.1; 604/6.1; 604/6.11 |
Current CPC
Class: |
A61M
1/30 (20130101); F04B 43/1253 (20130101); A61M
1/307 (20140204); Y10S 128/12 (20130101) |
Current International
Class: |
A61M
1/30 (20060101); F04B 43/12 (20060101); A61m
001/03 () |
Field of
Search: |
;128/214R,214E,214F,214.2,DIG.12,DIG.13 ;417/477,479 ;210/321 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Twiss - Lancet, Nov. 1964, No. 7369, p. 1106..
|
Primary Examiner: Truluck; Dalton L.
Attorney, Agent or Firm: Klarquist, Sparkman, Campbell,
Leigh, Hall & Whinston
Claims
I claim:
1. A single needle alternating flow blood pump system for alternate
removal of blood from a blood vessel and return to said blood
vessel via a single needle, said system comprising:
a blood flow path including a blood pump and tubing means
communicating between said needle and said blood pump for
withdrawing blood from said blood vessel,
blood receiving means also in said blood flow path through which
blood is circulated by said blood pump for subsequent return to
said needle,
valve means in said blood flow path by way of which the blood flow
is returned to said needle, said valve means being normally closed
for impeding the flow of blood to said needle as said pump operates
to withdraw blood therefrom,
and means operatively connected to both said pump and said valve
means and responsive to a given cyclical condition of said blood
pump during pumping operation thereof for cyclically interrupting
operation of said blood pump to interrupt withdrawal of blood for
predetermined time periods after said blood pump has withdrawn
substantially equal quantities of blood and for opening said valve
means to return said blood to said blood vessel through said
needle, whereby blood is alternately withdrawn and returned via the
same needle.
2. The system according to claim 1 wherein said blood receiving
means is located in said blood flow path between the outlet side of
said blood pump and said needle such that blood flows through said
receiving means in returning to said needle, and wherein said valve
means is disposed in said blood flow path between said blood
receiving means and said needle.
3. A flow system for alternate removal of liquid from and return of
liquid to a single passage comprising:
a flow loop connected at either end thereof to said single passage
for receiving liquid from said single passage and returning liquid
to said single passage,
a roller-and-flexible-tube pump having a tube thereof inserted in
said loop for producing the transport of liquid along said
loop,
said pump including a rotor carrying rollers for bearing against a
tube inserted in said loop, a guide for receiving said tube, and
means for rotating said rotor to force liquid along said tube,
a valve means located in said flow loop between the outflow side of
said pump and said single passage for temporarily impeding the
passage of liquid,
and means operatively connected to both said pump and said valve
means and responsive to a cyclical condition of said pump during
pumping operation thereof, for temporarily opening said valve means
and arresting operation of said pump for predetermined time periods
while at least one roller of said pump engages the said tube in
said pump.
4. The system according to claim 3 wherein said means for
temporarily opening said valve means comprises actuating means
responsive to rotational movement of the rotor of said pump,
said valve means comprising a section of tubing normally closed by
said actuating means until said pump reaches a predetermined pump
rotor position,
and timing means for returning said pump to a condition of rotor
rotation after a predetermined period of time.
5. A flow system for alternate removal of liquid from and return of
liquid to a single passage comprising:
a flow loop connected at either end thereof to said single passage
for receiving liquid from said single passage and returning liquid
to said single passage,
a roller-and-flexible-tube pump having a tube thereof inserted in
said loop for producing the transport of liquid along said
loop,
said pump including a rotor carrying rollers for bearing against a
tube inserted in said loop, a guide for receiving said tube, and
means for rotating said rotor to force liquid along said tube,
a valve means located in said flow loop for temporarily impeding
the passage of liquid,
means, responsive to a cyclical condition of said pump, for
temporarily opening said valve means and arresting operation of
said pump while at least one roller of said pump engages the said
tube in said pump, said means for temporarily opening said valve
means comprising actuating means responsive to rotational movement
of the rotor of said pump,
said valve means comprising a section of tubing comprising a
portion of said loop and normally closed by said actuating means
until said pump reaches a predetermined pump rotor position, said
actuating means comprising a spring-biased arm normally disposed in
clamping relation to said section of tubing, said arm being
positioned relative to the rotor of said pump so that rotation of
said rotor to a predetermined position moves said arm against
spring bias for unclamping said tubing,
and timing means for returning said pump to a condition of rotor
rotation after a predetermined period of time, said timing means
comprising timed switching means having contacts for providing
power to said pump after a predetermined time period whereby said
arm acts to re-clamp said tubing after said predetermined time
period.
6. The system according to claim 5 wherein said means for
temporarily opening said valve means and arresting operation of
said pump further comprises a limit switch operated by movement of
said arm, and means for connecting said limit switch in energizing
relation to said pump so that operation of said limit switch
disconnects said pump, said timed switching means being operated by
said limit switch.
7. The system according to claim 5 wherein said arm is rotatable,
having a forward portion on one side of the axis thereof engageable
by the rotor of said pump,
a clamping pin forming part of said valve means,
said arm having a second portion on the opposite side of the axis
thereof normally spring-biased against said clamping pin, said
tubing being disposed between said clamping pin and said arm
whereby said arm in its normally spring-biased position compresses
said tubing against said clamping pin, and wherein said operation
of said arm by rotation of said rotor to said predetermined
position rotates said arm away from said clamping pin and allows
liquid flow through said tubing.
Description
BACKGROUND OF THE INVENTION
In the use of an "artificial kidney," dialysis of the patient's
blood requires some means of withdrawing the blood from the
patient's body and returning the same after treatment. With
cannulae, providing permanent tubular connection to the patient,
connection of the patient to the dialyzer apparatus is facilitated.
However, a patient may not tolerate this arrangement because of
infection or the like. Alternatively, plural hypodermic needles may
be inserted in a patient's vein after insertion of a fistula
between a vein and artery, with one needle being utilized for
withdrawal of blood while a second needle is employed to return
blood to the vein. A more desirable system would avoid the
requirement for repeated insertion of both needles.
A prior art single needle system withdraws and returns blood via
the same hypodermic needle and includes a pair of clamp valves
employed in two connections to the hypodermic needle so that blood
can be alternately withdrawn and returned therethrough. In this
system the valves are solenoid operated in response to pressure
detected at a dialyzer output. However, pumping in such a system
tends to produce a vacuum at the pump inlet, flattening the plastic
tubing and causing cessation of system operation. Moreover, the
addition of solenoid operated valves represents additional
equipment and expense.
SUMMARY OF THE INVENTION
According to the present invention, a liquid flow loop is connected
at either end to a single path such as a hypodermic needle. This
loop includes pumping means for transporting liquid in the loop,
and valve means for temporarily impeding the passage of liquid. The
pumping means and the valve means operate synchronously for the
alternate pumping and opening of the valve means, whereby liquid is
alternately withdrawn and returned via the single path.
In accordance with a particular embodiment of the present
invention, the pumping means comprises a blood pump for receiving
blood from a single path, and means are responsive to the blood
pump operation for cyclically interrupting operation thereof
whereby withdrawal of blood is interrupted. At the same time, the
valve means is opened for returning blood via the single path.
It is accordingly an object of the present invention to provide an
improved alternating flow blood pump system and method for
alternate removal of blood from a blood vessel and return to said
blood vessel via a single needle.
It is a further object of the present invention to provide an
improved single needle alternating flow blood pump system and
method which is reliable in operation, and economical in
construction.
It is a further object of the present invention to provide an
improved single needle alternating flow blood pump system and
method which is readily adapted to a conventional blood pump.
It is a further object of the present invention to provide an
improved attachment for a conventional blood pump facilitating
withdrawal and return of blood from a patient.
It is a further object of the present invention to provide an
improved liquid flow system for withdrawing and returning liquid to
a single flow path from and to a loop attached thereto.
The subject matter which I regard as my invention is particularly
pointed out and distinctly claimed in the concluding portion of
this specification. The invention however, both as to organization
and method of operation together with further advantages and
objects thereof, may best be understood by reference to the
following description taken in connection with the accompanying
drawings wherein like reference characters refer to like
elements.
DRAWINGS
FIG. 1 is a plan view of a blood pump as modified according to the
present invention;
FIG. 2 is a partially broken away side view of the modified blood
pump taken at 2--2 in FIG. 1;
FIG. 3 is a partially broken away side view of the FIG. 1 blood
pump and attachment thereto according to the present invention,
said view being taken at 3--3 in FIG. 1;
FIG. 4 is a diagram illustrating an electrical control circuit
employed according to the present invention; and
FIG. 5 is a schematic illustration of an over-all system and method
according to the present invention, depicting the connection
thereof to a patient.
DETAILED DESCRIPTION
Referring to the drawings, and particularly to FIGS. 1, 2 and 3,
the system according to the present invention utilizes a
conventional blood pump of the roller-and-flexible-tube type
indicated at 10, said blood pump including a rotatable rotor 12
provided with rollers 14 and 16 mounted on spindles 18 and 20,
respectively, at corners of the rotor. When the rotor is rotated by
means of drive shaft 22, the rollers 14 and 16 alternately engage
pumping segment 24 of flexible plastic tubing disposed in a
semicircle around the inside of U-shaped guide 26, the pumping
segment being held in position by a crossbar 28 secured to the
front of the pump. As the rotor 12 rotates in a counterclockwise
direction, for example, the rollers rotate around the inside of
U-shaped guide 26 forcing the pumping segment against the inside
wall of the U-shaped guide and pumping blood in the direction
indicated by the arrows. Movable guides 30 are also suitably
mounted upon rotor 12 and act to keep the pumping segment aligned
in front of the rollers 14 and 16. The speed of rotor rotation is
suitably controlled by an adjusting knob 32 which is operative to
control the speed of the pump motor (not shown) which turns drive
shaft 22.
In accordance with an aspect of the present invention, an
attachment having a frame 34 may be mounted on the front of the
blood pump by means of bracket 36 secured to the blood pump with
bolts 38 extending through and also securing crossbar 40 to the
pump. A pivot pin 40 extends upwardly from the forward part of the
frame upon which an actuating arm generally indicated at 42 is
rotatable. This actuating arm includes a forward portion 44
comprising a hook-shaped rod secured to a rearward block portion 46
by means of a pair of bolts 50 extending through the block portion
46 on either side of pivot pin 40. The hook-shaped rod forward
portion 44 extends upwardly from the end of block 46, and over the
crossbar 28 for positioning forward end 52 in the path of upper
rollers 54 and 56 mounted upon spindles 18 and 20, respectively,
above the conventional rollers 14 and 16. As can be seen in FIG. 1,
the arm portion 44 is hooked toward the rotor drive shaft 22 and as
the rotor 12 turns, the upper rollers 54 and 56 will successively
engage forward end 52 of arm portion 44.
Block 46 is provided with a leaf spring 58, also secured thereto by
bolts 50, which normally urges block 46 toward clamping pin 60, the
latter extending upwardly from frame 34. The spring 58 bears
against upwardly extending spring retaining pin 62 which may be
horizontally slotted to receive the leaf spring. A section of
flexible plastic tubing 64 is normally received between the body of
block 46 and clamping pin 60 where it is normally compressed
between the two, as illustrated, to close off the flow of liquid,
i.e., blood, through tubing section 64. This portion of tubing
together with elements 46 and 60 comprise a valve or clamp
according to the present invention. For convenience in maintaining
the proper position of tubing section 64, the same is held between
a pair of horizontal pins 66 and 68 extending outwardly from block
46, the latter pin having an enlarged head for retaining the tubing
section 64 in position. It will be seen that as one of the rollers
54 or 56 contacts forward end 52 of arm portion 44 and causes the
arm 42 to rotate in a counterclockwise direction against the bias
of spring 58, the tubing section 64 will be unclamped to a
valve-open position from a valve-closed position.
Frame 34 further houses a limit switch 70 having an actuator 72
engageable by a downward extension 74 attached to block 46.
Rotation of arm 42 also operates the limit switch closing its
normally open contacts and opening its normally closed contacts, as
hereinafter more fully described. As also hereinafter more fully
described, the operation of the limit switch disconnects the blood
pump whereby the blood pump rotor 24 stops rotation in a position
wherein either roller 54 or roller 56 is in contact with arm
portion 44. The blood pump rotor at such time will be positioned so
that both rollers 14 and 16 compress pumping segment 24 at opposite
sides of U-shaped guide 26 whereby the blood pump 10 effectively
acts as a closed valve against the flow of blood into pumping
segment 24. After a predetermined period of time, as selected by
means of timer 76, power is restored to the blood pump motor and
rotation of rotor 12 resumes until the next one of the upper
rollers 54 or 56 contacts forward end 52 of arm portion 44. When
the blood pump rotor resumes rotation, arm 42 rotates clockwise to
its normal clamping position relative to tubing section 64, and
limit switch actuator 72 is also returned to its initial position
awaiting the turning of blood pump rotor 12 through 180 degrees.
The time during which the rotor is temporarily stopped, and tubing
section 64 is unclamped, is determined by the setting of timer
adjustment 78. Timer 78 is conveniently a conventional electric or
electronic timer and is connected as hereinafter more fully
described.
The blood pump 10 is of standard construction as hereinbefore
indicated but is suitably modified by upward extension of spindles
18 and 20 to support the upper rollers 54 and 56. Also, a cover 80
is raised above the level of rollers 54 and 56 by means of upper
supports 82 and 84.
FIG. 4 is an electrical circuit diagram illustrating the connection
of limit switch 70, timer 76, and blood pump motor 86. Limit switch
70 has a normally closed contact 88 and a normally open contact 90,
these contacts providing the indicated connection until actuator 72
is moved inwardly by extension 74 of block 46, whereupon the
movable contact 92 opens a circuit from power line 94 to contact 88
and closes a circuit from power line 94 to contact 90. One side of
blood pump motor 86 is connected to power line 96, and until
actuation of the limit switch, a circuit from the blood pump motor
is also completed to power line 94 through contacts 92 and 88
bringing about motor operation and rotation of rotor 12. However,
when the blood pump rotor moves to a position whereby arm 42 is
rotated in a counter-clockwise direction, the limit switch 70
disconnects motor 86 whereby blood pump rotor rotation is
temporarily halted. At the same time, timer coil 76a of timer 76 is
energized via limit switch contact 90, and at the conclusion of a
preset time period operating coil 76a closes normally open contacts
76b of the timer for re-energizing blood pump motor 86, the circuit
being completed from power line 94 through contacts 76b and the
blood pump motor to power line 96. Thereupon, the blood pump rotor
resumes rotation and the limit switch contacts resume their
position illustrated in the drawing whereby blood pump motor 86
remains energized after the timer contacts reopen. The blood pump
rotor will then continue rotation until the next upper roller
rotates arm 42, i.e., 180.degree. later.
The over-all system and method according to the present invention
is illustrated in FIG. 5 wherein the blood pump and attachment are
employed in a blood flow loop including the pump, a blood receiving
or treatment means typically comprising a dialyzer 98, a drip bulb
100, and a valve or clamp comprising block 46 and clamping pin 60
between which tubing section 64 is received. A blood flow loop
comprising a blood set alternately withdraws blood from a single
path comprising a hypodermic needle 102, drawing the blood through
the blood pump and into the dialyzer, and then expelling blood into
the hypodermic needle as the valve 46, 60 opens. Common connection
with both ends of the blood flow loop and the hypodermic needle is
made by Y connection means 104.
The blood receiving means 98 comprising a dialyzer or the like is
capable of receiving pressure as the membrane thereof expands
slightly such that blood is forced into the hypodermic needle when
valve 46, 60 opens. Thus, blood is drawn from the hypodermic needle
through tubing portion 106 and delivered to the dialyzer as the
pump rotor rotates through 180.degree.. At this time, the pump
rotor stops through the action of arm 42 and limit switch 70, while
valve or clamp 46, 60 opens returning blood to the hypodermic
needle via tubing portion 108. At such time, the blood pump rollers
14 and 16 themselves prevent the flow of blood through tubing
portion 106 in the direction of the pump, i.e., the pump acts as
the clamp or valve. After a predetermined time, governed according
to the timer 76, the pump resumes rotation and valve 46, 60 is
re-closed so that blood is once again withdrawn from the hypodermic
needle. In a typical instance, the timing of timer 76 and the speed
of rotation of the blood pump are adjusted so that the time of
rotation of the pump rotor through 180.degree. is approximately
one-half second, and the temporary interruption in blood pump
operation is also approximately one-half second.
The hypodermic needle 102 may be inserted in an arm vein of a
patient provided with a fistula by operative procedure, the latter
causing expansion of the vein and allowing easier insertion of the
hypodermic needle. The hypodermic needle, which may comprise a
14-gauge needle, is inserted in the direction of blood flow.
Typically, the patient must undergo periodic dialysis and thus must
reinsert the hypodermic needle at frequent intervals. The system
and method according to the present invention permits the insertion
of only one hypodermic needle, rather than two as in the case of
the more conventional procedure, and is of appreciable advantage
from the patient's point of view. The present system can also
effect 200 cc per minute transfer of blood. The system according to
the present invention, wherein blood is alternately withdrawn from
the vein of the patient and returned through a single hypodermic
needle, and wherein such withdrawal and return are synchronized
primarily according to the operation of the blood pump, is
preferable to a system wherein a pump is continuously operated
since in the latter instance undesired vacuum then produced on the
input side of the pump may cause tube flattening or the like.
Moreover, the present system does not require additional solenoid
operated clamps or pressure gauge control therefor but
advantageously functions in response to the cyclical operation of
the blood pump itself, or in synchronism therewith.
While I have shown and described the preferred embodiment of my
invention, it will be apparent to those skilled in the art that
many changes and modifications may be made without departing from
my invention in its broader aspects. I therefore intend the
appended claims to cover all such changes and modifications as fall
within the true spirit and scope of my invention.
* * * * *