Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FIELD OF THE INVENTION
This invention relates to apparatus adapted for
selectively aspirating and draining a body cavity and more
particularly to pneumothorax evacuation apparatus having a
non-return valve.
BACKGROUND OF THE INVENTION
Severe bodily trauma as may occur in a fall or
motor vehicle accident can easily result in one or more
fractured ribs that in turn may occasion a tear in a lung.
In the event of such occurrence, a tension pneumothorax
condition may result. Such a condition develops when the
injured lung collapses and permits the escape of some air
into the pleural cavity with each breath taken. As a result,
the cavity pressurizes. This condition is cumulative such
that the heart and blood vessels connected thereto are
displaced to one side together with the torn, collapsed lung
and the normal lung. The pressure in the cavity does not
equalize with the air pressure in the injured lung because of
the nature of the tear which acts as a non-return valve.
Thus, air escapes readily from the injured lung but does not
return. Eventually, sufficient air pressure buildup occurs in
the cavity so that the displaced heart will kink the blood
vessels connected thereto. This condition can lead to
circulatory failure and ensuing death.
As an emergency measure, immediate aspiration of
the pleural cavity is required and may be readily performed
even by semi-skilled medical attendants first on the scene.
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Most commonly, such attendants would be ambulance personnel
or possibly paramedical members of the medical profession.
Depending on the severity of the injury, the time available
for corrective measures may be exceedingly short so that it
i5 imperative to diagnose the condition and act immediately
with appropriate measures on site and en route to a hospital.
Symptomatic of tension pneumothorax is a blue
facial color. This symptom, however, may also arise from
other causes and is therefore not exclusively definitive of
tension pneumothorax. As a result, any corroborating test
for tension pneumothorax should be capable of quick
performance by relatively inexperienced personnel so that if
the problem is elsewhere suitable procedures may be followed.
Since the situation is imminently life threatening, speed and
accuracy of diagnosis are essential.
Medical apparatus for the aspiration of
pneumothorax is disclosed in United States Patent 4,592,741
Vincent which issued June 3, 1986. Although eminently well
adapted for the task of pneumothorax aspiration, the Vincent
apparatus is severely limited by the requirement for a source
of electrical power to activate a suction pump.
Another apparatus useful in the aspiration of
pneumothorax is intended for both aspirating and draining a
body cavity and is described in United States patent
4,664,660 Goldberg et al which issued May 12, 1987. The
Goldberg et al apparatus does not require a source of
electrical power and is portable to the extent that it may be
readily carried about in a small sterile kit. Due to the
sterile requirements under which such apparatus is used, the
Goldberg et al apparatus would likely be disposable.
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Nevertheless, the apparatus is relatively complex in
structure and, as a result, is expected to be expensive to
manufacture. Most significantly, however, the Goldberg at
al apparatus does not include any means to test for the
tension pneumothorax condition other than to note the
aspiration of air from the chest cavity which may not be
readily detected, particularly under noisy conditions.
SUMMARY OF THE INVENTION
A principal provision of the present invention is
apparatus for aspirating a pleural cavity that includes
pressure indicator means responsive to positive and negative
cavity pressures to indicate respectively the presence or
absence of tension pneumothorax.
Another provision of the invention is apparatus
employing check valve means with ambient air sealing for
selectively aspirating and draining the pleural cavity.
Still another provision of the invention is such
apparatus for selectively aspirating and draining the pleural
cavity where the apparatus is simple in structure and
consequently economical to manufacture.
The problems associated with the prior art may be
substantially overcome and the foregoing objectives achieved
by recourse to the present invention which relates to
apparatus for selectively aspirating and draining a body
cavity. The apparatus comprises housing means having side
walls defining an inlet chamber with a closed end in fluid
communication with a discharge chamber having an open
discharge port, check valve means including an inlet
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sealingly joined to the closed end and an outlet in operably
fluid communication with the inlet chamber, catheter means
including cannula means having one end adapted to enter the
pleural cavity, a body portion traversing the closed end, and
an opposite end communicating the cavity selectively with the
check valve means and the ambient atmosphere, and pressure
indicator means disposed within the housing means in fluid
communication with the cannula means to indicate the presence
of fluid pressure within the cavity.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be more particularly
described with reference to an embodiment thereof shown, by
way of example, in the accompanying drawings in which:
Fig. 1 is a perspective view, with portions broken
away, revealing the interior of apparatus for selectively
aspirating and draining a pleural cavity in accordance with
the present invention;
Fig. 2 is a cross-sectional view of Fig. 1 taken
along the lines 2-2;
Fig. 3 is a cross-sectional view of Fig. 1 taken
along the lines 3-3; and
Fig. 4 is a side elevation view of a cannula used
in the apparatus of Fig. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Apparatus for detecting and treating tension
pneumothorax is illustrated in a perspective vlew in Fig. 1
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and is shown generally as apparatus 10 for selectively
aspirating and draining a pleural cavity (not shown)
enclosing a collapsed lung. The apparatus 10 will be seen to
include housing means in the form of a cylinder 11 having a
side wall portion broken away to reveal a coaxial arrangement
therein of first and second check valves 12 and 13,
respectively. An inlet end of the cylinder 11 is closed by
means of a flanged closure 14 having attachment flanges 15
and 16 which may be best seen in Fig. 2. The flanges 15 and
16 extend radially outwardly from the cylinder 11 to
facilitate attachment to the chest surface of a patient as by
adhesive tape. A more secure attachment may be made by
sutures (not shown) which is facilitated by apertures 17 and
18.
Reference to Fig. 2 shows a cross-sectional profile
of the closure 14 wherein it will be observed that the
closure includes an inwardly facing tiered central portion 20
having an outwardly facing concavity 21. It will be
understood from Fig. 2 that the portion 20 comprises an
uppermost cylindrical tier 22 that is adapted to sealingly
engage and retain an inlet end of a thin walled cylinder 23
that comprises a body portion of the valve 12. An
intermediate cylindrical tier 24 correspondingly engages the
inlet end of a thin walled cylinder 25 that forms the body
portion of the valve 13. A lowermost cylinder tier 26 is
similarly adapted to sealingly engage and retain an inlet end
of the cylinder 11.
Further reference to Fig. 2 shows the coaxial
arrangement of the cylinders 11, 23 and 25, together with a
catheter 30 that comprises a flexible plastic tube 31 of
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small diameter having open ends. One end of the tube 31 is
referred to herein as a body portion 32 having thick side
walls that are sealingly fixed within a passage 33 that leads
through the closure 14 into fluid communication with the
interior of the valve 12.
Fig. 2 also illustrates the coaxial placement of a
cannula 35, shown in enlarged detail in Fig. 4.
Fundamentally, the cannula 35 comprises a stainless steel
hollow needle 36 which is of small diameter and is adapted to
slidably traverse the flexible tube 31. It will be seen that
the needle 36 includes an open sharp end 37 that is adapted
to pierce through the chest wall of a subject into the
pneumothorax which is also referred to herein as a pleural
cavity. In so doing, the tube 31 is concurrently carried
into the cavity. The other end of the needle 36 is provided
with an open blunt end 38.
A receiver 39 forms part of the cannula 35 and
includes a longitudinal body portion as shown which defines a
chamber 40 with open ends. It will be observed that one end
of the chamber 40 receives and fixedly secures the blunt end
38 of the needle 36 and that the opposite end of the chamber
40 is openably closed with a removable plug 41 .
Additionally, a side port 42 extends radially outwardly of
the receiver 39 and is in fluid communication with the
chamber 40. A free end of the port 42 is adapted to be
attached by known means to a self-supporting balloon 45 that
functions as a pressure indicator in fluid communication with
the cannula 35 to indicate the presence of fluid pressure
within the pleural cavity.
Support for the cannula 35 within the cylinder 11
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is provided by a support bar 46 which also distinguishes the
inlet chamber of the cylinder 11, housing the valves 12 and
13, from a discharge chamber 63 that includes an open
discharge port 47. The port 47 is circumscribed by an
5 axially extending collar 48 that is adapted to receivably
retain one end of a suction tube 49 as illustrated.
Frictional engagement of the tube 49 with the collar 48 is
attained in a known manner by forcing the tube 49, which is
resilient, over the collar 48.
It will be understood that the bar 46 includes an
aperture 50 into which the receiver 39 fits, the receiver
being held in a predetermined position by means of an annular
flange 51.
Physically, the apparatus 10 is sized to be held
15 comfortably with one hand. To ensure that the apparatus 10
does not slip from the grip of the user during use, a pair of
grip flanges 53 and 54 are provided. These flanges extend
radially outwardly from the cylinder 11 to facilitate use of
the apparatus 10 with one hand.
As previously described, the valve 12 includes a
body portion fabricated from the cylinder 23 having its open
end sealably j oined to the tier 22. The other end of the
cylinder 23 is closed by means of a self-sealing elastomeric
plug 55 through which the needle 36 is retractably driven.
Reference to Fig. 1 shows clearly that the side
walls of the cylinder 23 include a plurality of apertures 60.
A thin resilient latex sheath 61 overlies the external
surface of the cylinder 23 and is in intimate contact
therewith. Each aperture 60 is therefore normally closed by
30 the sheath 61 and is opened only when the interior of the
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cylinder 23 is acted upon by fluid pressure from the pleural
cavity which causes the sheath 61 to be raised. This
arrangement provides a corresponding plurality of flap valves
so that fluid under pressure entering the valve 12 through
the catheter 30 may escape through the apertures 60 into the
second valve 13 which is structured in a like manner to the
valve 12. Accordingly, the pressurized fluid entering the
valve 13 may escape through the apertures 60 into the inlet
side of the cylinder 11 and therefrom through passages 62
into the discharge chamber 63 from which the pressurized
fluid exits through the port 47. The valves 12 and 13 thus
act as non-return valves since fluid under pressure may only
pass unidirectionally through the valves. A return flow is
prevented by the sheath 61.
Corresponding to the plug 55, a self-sealing
elastomeric plug 64 closes one end of the cylinder 25.
In order to selectively aspirate and drain a
pleural cavity enclosing a collapsed lung, the sharpened end
37 of the needle 36, which extends axially outwardly of the
tube 31, is forced into the cavity through the side wall of
the chest. As previously disclosed, this action carries the
tube 31 into the cavity as well. If a tension pneumothorax
condition is present, the balloon 45 will dimensionally
respond to a positive pressure within th^ cavity by
increasing in size. Alternatively, a negative pressure in a
normal pleural cavity will cause the balloon 45 to decrease
in size. In this respect, the balloon is fabricated from
latex of sufficient thickness to prevent collapse of the
balloon at ambient atmospheric pressure and to dimensionally
change in size responsive to fluid pressure within the
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cavity. The condition of tension pneumothorax may therefore
be readily and immediately recognized. Aspiration of the
pleural cavity may then follow by removing the cannula 35 and
joining the tube 49 with the collar 48 or by removing the
plug 41 and inserting a corresponding open end of a syringe
(not shown) into the receiver 39 to withdraw a predetermined
quantity of air from the cavity. Use of the syringe permits
removal of the air in a controlled manner so that an
excessive amount of air is not withdrawn. Excessive air
removal can result in too low a pressure within the cavity
that could cause severe complications. As the air is
withdrawn through the syringe, the balloon 45 continues to
monitor the air pressure and to indicate clearly whether
additional air is to be removed by the syringe and when air
withdrawal should be temporarily halted so as not to lower
excessively the air pressure within the pleural cavity.
Normally the discharge port 47 remains open so as
to facilitate connection of the syringe (not shown) with the
receiver 39 as described. Should, however, draining the
cavity be required, the cannula 35 and its needle 36 are
first withdrawn through the port 47. This permits the plugs
55 and 64 to seal. The tube 49 is then joined to the collar
48 and suction is applied to withdraw fluids from the cavity
by way of the catheter 30 and the valves 12 and 13.
Withdrawal of the cannula 35 thus permits communicating the
cavity selectively with the check valves. Alternatively,
reinsertion of the cannula 35 permits selective fluid
communication of the cavity with the ambient atmosphere or
the syringe as described.
To those individuals skilled in the art to whom
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this specification is addressed, it will be apparent that the
embodiment heretofore described may be varied to meet
particular requirements without departing from the true
spirit and scope of the invention disclosed. For example,
instead of a self-supporting balloon 45, some other indicator
means may be used to detect the presence of fluid pressure.
An example would be a piezoelectric pressure transducer
coupled to the port 42. Another variation may be the
addition of side apertures (not shown) adjacent the sharp end
37 of the needle 36 to facilitate fluid removal from the
pleural cavity. Accordingly, the foregoing embodiment is
therefore not to be taken as indicative of the limits of the
invention but rather as an exemplary structure of the
invention which is described by the claims appended hereto.
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