U.S. patent number 3,769,960 [Application Number 05/244,534] was granted by the patent office on 1973-11-06 for intra-aortic balloon system.
This patent grant is currently assigned to The United States of America as represented by the Secretary, Department. Invention is credited to Thomas C. Robinson.
United States Patent |
3,769,960 |
Robinson |
November 6, 1973 |
INTRA-AORTIC BALLOON SYSTEM
Abstract
An intra-aortic balloon system includes a balloon adapted to be
disposed within an aorta and to change from a minimum volume to a
maximum volume at which the balloon substantially but not entirely
fills the aorta. The change in balloon volume is effected by
connecting the balloon through a catheter to a slave casing cup
covered by a diaphragm. The balloon, catheter and covered slave
casing cup constitute a substantially closed volume filled with
physiologically acceptable gas. Movement of the diaphragm portion
of the closed volume produces a substantially equal volume
variation of the balloon. A master casing cup is disposed against
the other side of the diaphragm and is supplied with a working gas,
the pressure of which is changed according to a program. Leakage of
physiologically acceptable gas is detected and made up when
necessary. The slave casing cup volume is changeable to match
different balloons or to match the same balloon under changed
operating conditions.
Inventors: |
Robinson; Thomas C. (El
Cerrito, CA) |
Assignee: |
The United States of America as
represented by the Secretary, Department (Washington,
DC)
|
Family
ID: |
22923160 |
Appl.
No.: |
05/244,534 |
Filed: |
April 17, 1972 |
Current U.S.
Class: |
600/18; 92/98R;
604/914 |
Current CPC
Class: |
A61M
60/50 (20210101); A61M 60/40 (20210101); A61M
60/268 (20210101); A61M 60/135 (20210101); A61M
60/274 (20210101) |
Current International
Class: |
A61M
1/10 (20060101); A61b 019/00 () |
Field of
Search: |
;128/1D,214R,274
;417/383,389 ;92/5R,13.1,13.2,13.6,97,98,107 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Madras et al.-Trans. Amer. Soc. Art. Inter. Orgs. Vol. XV, 1969 pp.
400-405. .
Moulopolous et al.-Trans. Amer. Soc. Art. Inter. Orgs. Vol. VIII,
1962, pp. 85-87..
|
Primary Examiner: Truluck; Dalton L.
Claims
What is claimed is:
1. An intra-aortic balloon system comprising a slave casing cup
having a peripheral flange; a slave gas connector opening into said
slave casing cup; a master, casing cup having a peripheral flange;
means movably engaging said master casing cup flange; a master gas
connector opening into said master casing cup; means including at
least one diaphragm between said cups engaging said peripheral
flanges and overlying said casing cups for movement through a
central position and between deflected positions on opposite sides
of said central position; means including the walls of said casing
cups for limiting said movement of said diaphragm; an aortic
balloon; a catheter at one end joined to and communicating with
said aortic balloon and at the other end joined to and
communicating with said slave gas connector, said aortic balloon,
said catheter, said slave casing cup and said diaphragm together
defining a substantially closed volume; means for supplying a
physiologically acceptable gas to said substantially closed volume;
a supply of working gas under pressure; means for supplying said
working gas under pressure to said master casing cup to move said
diaphragm; and means for imposing a programmed pressure change
cycle on said working gas supplied to said master cup.
2. A system as in claim 1 in which said limiting means includes
conical walls of said casing cups.
3. A system as in claim 1 in which said means movably engaging said
master casing cup flange comprises means for moving said master
casing cup and said slave casing cup toward and away from each
other.
4. A system as in claim 1 in which said slave casing cup has a
mouth, said diaphragm overlies said mouth and on one side engages
said peripheral flange of said slave casing cup, said means movably
engaging said master casing cup flange comprises a ring engaging
the other side of said diaphragm, and means for urging said
peripheral flange of said slave casing cup and said ring toward
each other.
5. A system as in claim 4 in which said ring is provided with first
threads, and said master casing cup has second threads engaging
said first threads.
Description
The invention described herein was made in the course of, or under,
a contract with the Department of Health, Education, and
Welfare.
In recent years successful techniques have been provided for
assisting the action of the heart in individuals having heart
difficulties. One of the ways is by means of a catheter to
introduce a relatively elongated, flexible balloon, connected to
the catheter, into the aorta of an individual. By appropriately
expanding and contracting the balloon there is effectuated a blood
pumping action assisting the natural pumping action of the heart.
The variation in balloon volume is timed to afford the best
results.
While this technique is valuable and is increasingly acceptable,
there are still some difficulties. The balloon is expanded and
contracted in response to variations in pressure of a contained
actuating gas. Care must be taken that this gas is physiologically
acceptable and readily dissolved in blood. A poorly absorbed gas
such as air or helium is dangerous and even fatal in the event any
part of the structure within the aorta or connecting blood vessels
fails and releases the air or helium to the blood. Variation in
pressure and volume of the balloon must be carefully regulated and
timed according to a program. Overexpansion of the balloon
obstructs or blocks the aorta, hinders rather than helps the heart
action, and damages the contacted aorta surface.
There is sometimes difficulty in properly selecting the balloon for
the particular aorta with which it is momentarily utilized. Not
only does the aorta size vary from individual to individual but
also the aorta size varies from time to time in a specific
individual, depending largely upon his condition of health and the
pressure of his blood. In fact, it is sometimes necessary to have
multiple insertions and removals to change the size of intra-aortic
balloons used as the patient recovers. As his blood pressure
increases, the diameter or size of the aorta may increase also.
It is therefore an object of the invention to provide an
intra-aortic balloon system in which the volume variation of the
balloon can be very carefully regulated to afford a substantially
predetermined or maximum pumping effect without the risk or danger
of expanding the balloon to an extent that the aorta is entirely
occluded.
Another object of the invention is to provide an intra-aortic
balloon system in which the periodic variation in balloon size can
be carefully controlled and regulated, particularly as to maximum
balloon size.
A further object of the invention is to provide an intra-aortic
balloon system in which a mechanical rupture or failure of the
balloon or its connecting catheter is not of a dangerous or serious
nature.
Another object of the invention is to provide an intra-aortic
balloon system in which the balloon volume change can be varied
from time to time from the outside and without the necessity of
changing balloons.
A further object of the invention is to provide an intra-aortic
balloon system in which a substantially constant, small volume of
actuating gas is maintained in the balloon catheter system.
A further object of the invention is to afford special actuation of
the system in the event there is an excessive leakage of actuating
gas.
Another object of the invention is to use air or a common gas as
the principal working gas.
A further object of the invention is in general to provide an
improved intra-aortic balloon system.
Other objects together with the foregoing are attained in the
embodiment of the invention described in the accompanying
description and illustrated in the accompanying drawings, in
which:
FIG. 1 is a diagram, many parts being in cross-section on a median
plane, showing an intra-aortic balloon system pursuant to the
invention as it is actually employed;
FIG. 2 is a cross-section, the plane of which is indicated by the
line 2--2 of FIG. 1;
FIG. 3 is a cross-section through a part of a modified master and
slave unit employed in the system; and
FIG. 4 is a view similar to FIG. 3 showing a further modified form
of master and slave mechanism utilized in the intra-aortic balloon
system, parts being shown in cross-section, parts being broken away
and other parts being diagrammatic.
In a preferred form and as it has been worked out and adapted for
use in a human aorta 6 having a reasonably well known but perhaps
variable cross-section or diameter, I preferably provide a flexible
catheter 7 of a recognized sort that is readily introduced through
a blood vessel and extends into the aorta. The distal end 8 of the
catheter is preferably closed and in the vicinity of that end the
catheter is provided with a number of apertures 9 affording access
from the interior of the catheter to the interior volume 11 of a
balloon 12. The ends of the balloon are preferably firmly attached
to the catheter end 8 and also to an intermediate zone of the
catheter so that while the interior volume 11 of the balloon is in
free communication with the interior volume of the catheter, the
balloon itself is substantially closed and is not in communication
with the interior of the aorta 6.
The catheter 7 on the outside of the body is preferably provided
with a connection 13 to a mechanism for varying the pressure within
the catheter and within the balloon 12 so as correspondingly to
expand and contract the balloon. Particularly in accordance with
the invention, it is preferred to provide a substantially closed
system for this purpose. Consequently, the catheter connection 13
extends to a slave gas connector 14 on a slave casing cup 16. As an
example, this is a conical body having a peripheral flange 17. The
interior of the cup is in free communication through the catheter 7
with the balloon interior 11. Extending across the slave casing cup
is a flexible diaphragm 18 on one side exposed to the interior
volume of the slave cup. On the other side the diaphragm is exposed
to the interior volume of a master casing cup 21. This cup has a
flange 22 appropriately secured to the flange 17, preferably with
the diaphragm 18 clamped therebetween. The master casing cup 21 has
a fitting 23 receiving a tube 24 which extends to an actuator
26.
The actuator is a power driven mechanism subject to the control of
an input signal received through a line 27 either from a timing
device or from the patient himself, such as a signal from his
heart. When appropriately signaled the actuator 26 takes in a
working gas such as atmospheric air from an inlet 28 and forces the
working gas out through the tube 24 and into the master cup 21. The
effect of this is to increase the pressure within the cup 21 acting
against the diaphragm 18. The momentarily superior pressure
distorts the diaphragm 18 and displaces it into the slave casing
cup 16 until the diaphragm comes into contact with the walls of
that casing cup. This limits the volume change due to the diaphragm
entering the slave casing cup to a predetermined or set value.
Stated differently, it is immaterial how high the pressure may
happen to rise within the master chamber 21, the diaphragm can
displace through a certain volume only and that is all since
thereafter the diaphragm simply rests against and is supported by
the walls of the slave casing cup.
Use of atmospheric air on the master side of the diaphragm is safe
since all of that part of the structure is outside the body and
breakage or leakage is not critical. Large volumes of air can be
used, if desired, without an economic penalty.
The balloon volume system, including the slave casing cup, the
catheter and the balloon, is preferably substantially closed in
order to maintain a fixed or constant volume. The gas therein
utilized is either an inert gas or a gas that is physiologically
acceptable, such as carbon dioxide. The volume is small so that the
cost of a special gas is not great. In the event of rupture of the
balloon or of the catheter within the body, the amount of gas that
can escape is thus strictly limited. Since the gas is innocuous its
escape, although perhaps unwanted, is not dangerous.
To supply the substantially closed balloon gas volume with a proper
gas, the slave casing cup 16 is provided with a tube 31 extending
to a suitable source 32 of an acceptable gas under some small
pressure. A valve 33 is interposed in the tube 31 so that the slave
casing cup can be entirely cut off from the gas source 32 or can,
under proper control, be opened to such source.
In the general operation of this structure the actuator 26 under
control of a signal through the line 27 varies the working gas
pressure in the master casing cup 21 in a programmed or
predetermined fashion as to timing and duration or pattern of
pressure fluctuation alternately increasing and decreasing the
interior pressure in the master casing cup. There is
correspondingly produced, by deflection of the diaphragm, a
comparable pressure fluctuation in the slave casing cup. This
pressure fluctuation is transmitted through the closed system to
afford a corresponding volume variation of the balloon 12.
Should it be observed at any time that the volume of the balloon
system is reduced due to a hole, diffusion, or other gas leakage,
(and some leakage is virtually inevitable) then the valve 33 can be
momentarily opened to replenish the gas supply to the balloon or
slave system and restore the gas content to the proper amount.
While a large variation in pressure within the actuator 26 is not
particularly critical, nevertheless the pressure within the master
casing cup can readily be monitored and if it goes below a set or
desired value or outside a selected range the actuator 26 can
readily be operated to make up the deficiency or release the excess
and so restore the desired operating pressure values.
Particularly in accordance with the invention, I afford means for
varying the volume of the slave casing cup so that the balloon can
be made to cycle in different diameter ranges. it can thus be made
to follow enlargement of the aorta due to increasing blood
pressure. It is also thus feasible to insert a standard size inert
balloon into aortas of different sizes and then operate the balloon
through a desired size range, always with the aim of obtaining
maximum pumping without complete obstruction of the aorta, i.e.,
always keeping the balloon from touching much of the aorta
wall.
To that end, as particularly shown in FIG. 3, the diaphragm 18 is
mounted across the mouth of the slave casing cup 16 by means of a
ring 36 urged toward a special flange 37 on the slave casing cup by
a plurality of fasteners 38. The interposed diaphragm is properly
clamped. The ring 36 is formed with external threads 39 with which
mate internal threads 41 on the interior of a flange 41 included in
the master casing cup 21. Preferably, the configuration of the
interior wall 43 of the master casing cup is made to follow quite
closely the desired configuration of the diaphragm 18 when flexed
in one direction.
When the parts are in the position shown in FIG. 3 and the casing
cups are quite close together, the diaphragm 18 can flex between
the two extreme positions shown by the broken lines in that figure,
being then almost entirely supported on one or the other of the
adjacent cup walls. The excursion of the diahragm is a minimum
amount in this case so that a minimum volume change occurs. When
the cups are rotated relative to each other on the threads, they
are spaced farther apart in an axial direction. The diaphragm 18
then can have a greater excursion before resting upon the cup walls
at its extreme positions. A greater volume is swept through. By
appropriately rotating the cups relative to each other so that
greater diaphragm flexure and distortion can occur, a variation in
volume of the always closed balloon gas system is effectuated. This
can be accomplished at anytime, even during the operation of the
structure so that changes in aorta size or aortas of different
original diameter can immediately be compensated for.
Since at the present time, with presently acceptable materials and
gases some minor leakage seems to be unavoidable, I sometimes
prefer to use a construction as illustrated in FIG. 4. This is
generally identical with all of the structure previously described
except that in addition to the single diaphragm 18 I preferably
utilize a second diaphragm 46 overlying the diaphragm 18 and
clamped into position therewith. There is an exception in that
between the peripheries of the diaphragms 18 and 46 there is
interposed a washer 47 having at least one radial passage 48
therethrough leading to an outlet pipe 49. Leakage through the
diaphragm 18, therefore, can discharge through the pipe 49 directly
to the atmosphere.
Preferably, any gas discharge is monitored. One way of
accomplishing this is to provide a pressure gauge 51 on the pipe 49
in an upstream portion and to restrict the pipe so that the
pressure gauge 51 affords an indication of the amount of gas
escaping.
In lieu of or in addition to the gauge 51 there can be provided an
enlarged chamber 52 connected to the pipe 49 and carrying a disc 53
having a restricted orifice 54 therein. The chamber 52 is connected
to a duct 56 leading to an evacuating device. Lines 57 and 58
connected on opposite sides of the orifice 54 lead to a sensor 59
actuated when the pressure drop across the orifice 54 becomes
excessive. When actuated the sensor 59 sends out a signal to a line
61 (FIG. 4) received through the line 61 (FIG. 1) to operate an
actuator 62. This correspondingly terminates the balloon pumping
and evacuates line 24.
As a further refinement, the mechanism lends itself to the use of a
pressure sensor 63 detecting aortic blood pressure and effective
upon an actuator 64 to move the cups 16 and 21 with respect to each
other so that the volume swept through by the diaphragm is
automatically varied pursuant to blood pressure.
* * * * *