Note: Descriptions are shown in the official language in which they were submitted.
CA 02466636 2004-05-07
LOCALIZED PLEURODESIS CHEMICAL DELIVERY
CROSS REFERENCE TO RELATED APPLICATIONS
S
This application claims the benefit of Provisional Application Number
60/468,415 filed May 7, 2003.
Background of the Invention
1. Field of the Invention
The present invention relates to systems and methods for removing
trapped air in emphysematous lungs, and more particularly, to systems and
IS methods for removing trapped air in emphysematous hyperinflated lungs by
bypassing non-patent airways via a conduit through the outer pleural layer of
the lung to a containrnent/trap device. The present invention also relates to
systems and methods for chemical pleurodesis.
2. Discussion of the Related Art
As a result of studies that date back to the 1930's and particularly
studies conducted in the 1960's and early 1970'x, it has been determined that
long-term continuous oxygen therapy is beneficial in the treatment of
hypoxemic pafients with chronic obstructive pulmonary disease. In other
words, a patient's life and quality of life can be improved by providing a
constant supplemental supply of oxygen to the patient's lungs.
However, with the desire to contain medical costs, there is a growing
concern that the additional cost of providing continuous oxygen therapy for
chronic lung disease will create an excessive increase in the annual cost of
oxygen therapy. Thus; it is desirable that oxygen therapy, when provided; be
as cost effective as possible.
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CA 02466636 2004-05-07
The standard treatment for patients requiring supplemental oxygen is
still to deliver oxygen from an oxygen source by means of a nasal cannula.
Such treatment, however, requires a large amount of oxygen, which is wasteful
and can cause soreness and irritation to the nose, as well as being
potentially
aggravating. Other undesirable effects have also been reported. Various other
medical approaches which have been proposed to help reduce the cost of
continuous oxygen therapy have been studied.
Various devices and methods have been devised for performing
emergency cricothyroidotomies and for providing a tracheotomy tube so that a
patient whose airway is otherwise blocked may continue to breath. Such
devices are generally intended only for use with a patient who is not
breathing
spontaneously and are not suitable for the long term treatment of chronic lung
disease. Typically, such devices are installed by puncturing the skin to
create
a hole into the cricoid membrane of the larynx above the trachea into which a
relatively large curved tracheotomy tube is inserted. As previously described,
the use of such tubes has been restricted medically to emergency situations
where the patient would otherwise suffocate due to the blockage of the airway.
Such emergency tracheotomy tubes are not suitable for long term therapy after
the airway blockage is removed.
Other devices which have been found satisfactory for emergency or
ventilator use are described in U.S. Patent Nos. 953,922 to Rogers; 2,873,742
to Shelden; 3,384,087 to Srummelkamp; 3,511,243 to Toy; 3,556,103 to
Caihoun; 2,991,787 to Sheiden, et at; 3,688,773 to Weiss; 3,817,250 to Weiss,
et al.; and 3,916,903 to Pozzi.
Although tracheotomy tubes are satisfactory far their intended purpose,
they are not intended for chronic usage by outpatients as a means for
delivering supplemental oxygen to spontaneously breathing patients with
chronic obstructive pulmonary disease. Such tracheotomy tubes are generally
designed so as to provide the total air supply to the patient for a relatively
short
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CA 02466636 2004-05-07
period of time. The tracheotomy tubes are generally of rigid or semi-rigid
construction and of caliber ranging from 2.5 mm outside diameter in infants to
15 mm outside diameter in adults. They are normally inserted in an operating
room as a surgical procedure or during emergency situations, through the
crico-thyroid membrane where the tissue is less vascular and the possibility
of
bleeding is reduced. These devices are intended to permit passage of air in
both directions until normal breathing has been restored by other means.
Another type of tracheotomy tube is disclosed in Jacobs, U.S. Pat. Nos.
3,682,166 and 3,788,326. The catheter described therein is placed over 14 or
16 gauge needle and inserted through the crico-thyroid membrane for
supplying air or oxygen and vacuum on an emergency basis to restore the
breathing of a non-breathing patient. The air or oxygen is supplied at 30 to
100
psi for inflation and deflation of the patient's lungs. The Jacobs catheter,
like
the othertracheotomy tubes previously used, is not suitable for long term
outpatient use, and could not easily be adapted to such use.
Due to the limited functionality of tracheotomy tubes, transtracheal
catheters have been proposed and used for long term supplemental oxygen
therapy. For example the small diameter transtracheal catheter (16 gauge)
developed by Dr. Henry J. Heimlich (described in THE ANNALS OF
OTOLOGY, RHiNOLOGY & LARYNGOLOGY, November-December 1982;
Respiratory Rehabilitation with Transtracheal Oxygen System) has been used
by the insertion of a relatively large cutting needle (14 gauge) into the
trachea
at the mid-point between the cricothyroid membrane and the sternal notch.
This catheter size can supply oxygen up to about 3 liters per minute at low
pressures, such as 2, psi which may be insufficient for patients who require
higher flow rates. It does not, however; lend itself to outpatient use and
maintenance, such as periodic removal and cleaning, primarily because the
connector between the catheter and the oxygen supply hose is adjacent and
against the anterior portion of the trachea and cannot be easily seen and
manipulated by the patient. Furthermore, the catheter is not provided with
positive means to protect against kinking or collapsing which would prevent
its
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CA 02466636 2004-05-07
effective use on an outpatient basis. Such a feature is not only desirable but
necessary for long term outpatient and home care use. Also, because of its
structure, i.e, only one exit opening, the oxygen from the catheter is
directed
straight down the trachea toward the bifurcation between the bronchi: Because
of the normal anatomy of the bronchi wherein the left bronchus is at a more
acute angle to the trachea than the right bronchus, more of the oxygen from
that catheter tends to be directed into the right bronchus rather than being
directed or mixed for more equal utilization by both bronchi: Also, as
structured, the oxygen can strike the carina, resulting in an undesirable
tickling
sensation and cough. In addition; in such devices, if a substantial portion of
the oxygen is directed against the back wall of the trachea causing erosion of
the mucosa in this area which may cause chapping and bleeding. Overall,
because of the limited output from the device, it may not operate to supply
sufficient supplemental oxygen when the patient is exercising or otherwise
quite active or has severe disease.
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Diseases associated with chronic obstructive pulmonary disease include
chronic bronchitis and emphysema. One aspect of an emphysematous lung is
that the communicating filow of air between neighboring air sacs is much more
prevalent as compared to healthy lungs. This phenomenon is known as
collateral ventilation. Another aspect of an emphysematous lung is that air
cannot be expelled from the native airways due to the loss of tissue elastic
recoil and radial support of the airways. Essentially, the loss of elastic
recoil of
the lung tissue contributes to the inability of individuals to exhale
completely.
The loss of radial support of the airways also allows a collapsing phenomenon
to occur during the expiratory phase of breathing. This collapsing phenomenon
also intensifies the inability for individuals to exhale completely. As the
inability
to exhale completely increases, residual volume in the lungs also increases.
This then causes the lung to establish in a hyperinflated state where an
individual can only take short shallow breaths. Essentially, air is not
effectively
expelled and stale air accumulates in the lungs. Once the stale air
accumulates in the lungs, the individual is deprived of oxygen.
Currently, treatments for chronic obstructive pulmonary disease include
bronchodilating drugs, oxygen therapy as described above, and lung volume
reduction surgery. Bronchodilating drugs only work on a percentage of patients
with chronic obstructive pulmonary disease and generally only provides short
term relief. Oxygen therapy is impractical for the reasans described above,
and lung volume reduction surgery is an extremely traumatic procedure that
involves removing part of the lung. The long term benefits of lung volume
reduction surgery are not fully known.
Accordingly, there exists a need for increasing the expiratory flow from
an individual suffering from chronic obstructive pulmonary disease.
Summary of the Invention
The present invention overcomes the disadvantages associated with
treating chronic obstructive pulmonary disease, as briefly described above, by
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CA 02466636 2004-05-07
utilizing the phenomenon of collateral ventilation to increase the expiratory
flow
from a diseased lung.
In accordance with one aspect, the present invention is directed to a
device for the local delivery of a pleurodesis agent, the device comprising a
catheter having one or more fluid carrying conduits and a distal tip attached
to
and in fluid communication with the catheter, the distal tip being sized and
configured to deliver a pleurodesis agent to a predetermined area in a pleural
space of a patient.
in accordance with another aspect, the present invention is directed to a
device for the local delivery of a pleurodesis agent, the device comprising an
implantable medical device for implantation at a predetermined site in a
pleural
space of a patient and a pleurodesis agent affixed to the implantable medical
device.
The long term oxygen therapy system of the present invention delivers
oxygen directly to diseased sites in a patient's lungs. t-ong term oxygen
therapy is widely accepted as the standard treatment for hypoxia caused by
chronic obstructive pulmonary disease, for example, pulmonary emphysema.
Pulmonary emphysema is a chronic obstructive pulmonary disease wherein the
alveoli of the lungs lose their elasticity and the walls between adjacent
alveoli
are destroyed. As more and more alveoli walls are lost, the air exchange
surtace area of the lungs is reduced until air exchange becomes seriously
impaired. The combination of mucus hypersecretion and dynamic air
compression is a mechanism of airflow limitation in chronic obstructive
pulmonary disease. Dynamic air compression results from the loss of tethering
forces exerted on the airway due to the reduction in lung tissue elasticity.
Essentially, stale air accumulates in the lungs, thereby depriving the
individual
of oxygen. Various methods may be utilized to determine the location or
locations of the diseased tissue, for example, computerized axial tomography
or CAT scans, magnetic resonance imaging or MRI, positron emission
tomograph or PET, andlor standard X-ray imaging. Once the location or
6
CA 02466636 2004-05-07
locations of the diseased tissue are located, anastomotic openings are made in
the thoracic cavity and lung or lungs and one or more oxygen carrying conduits
are positioned and sealed therein. The one or more oxygen carrying conduits
are connected to an oxygen source which supplies oxygen under elevated
pressure directly to the diseased portion or portions of the lung or lungs.
The
pressurized oxygen essentially displaces the accumulated air and is thus more
easily absorbed by the alveoli tissue. In addition, the long term oxygen
therapy
system may be configured in such a way as to provide collateral ventilation
bypass in addition to direct oxygen therapy, In this configuration, an
additional
conduit may be connected between the main conduit and the individual's
trachea with the appropriate valve arrangement. In this configuration, stale
air
may be removed through the trachea when the individual exhales since the
trachea is directly linked with the diseased site or sites in the lung via the
conduits.
The long term oxygen therapy system of the present invention improves
oxygen transfer efficiency in the lungs thereby reducing: oxygen supply
requirements, which in tum reduces the patient's medical costs. The system
also allows for improved self image, improved mobilify, greater exercise
capability and is easily maintained.
The above-described long term oxygen therapy system may be utilized
to effectively treat hypoxia caused by chronic obstructive pulmonary disease;
however; other means may be desirable to treat other aspects of the disease:
As set forth above, emphysema is distinguished as irreversible damage to lung
tissue. The breakdown of lung tissue leads to the reduced ability for the
lungs
to recoil. The tissue breakdown also leads to the loss of radial support of
the
airways. Consequently, the loss of elastic recoil of the lung tissue
contributes
to the inability for individuals with emphysema to exhale completely. The loss
of radial support of the airways also allows a collapsing phenomenon to occur
during the expiratory phase of breathing. This collapsing phenomenon also
intensifies the inability for individuals to exhale completely. As the
inability to
exhale increases; residual volume in the lungs also increases. This then
CA 02466636 2004-05-07
causes the lung to establish in a hyperinflated state wherein an individual
can
only take short shallow breaths.
The collateral ventilation bypass trap system of the present invention
utilizes the above-described collateral ventilation phertomenan to increase
the
expiratory flow from a diseased lung or lungs, thereby treating another aspect
of chronic obstructive pulmonary disease. Essentially, the most collaterally
ventilated area of the lung or lungs is determined utilizing the scanning
techniques described above. Once this area or areas are located, a conduit or
conduits are positioned in a passage or passages that access the outer pleural
layer of the diseased Jung or lungs. The conduit or conduits utilize the
collateral ventilation of the lung or lungs and allow the entrapped air to
bypass
the native airways and be expelled to a containment system outside of the
body.
IS
in order for the system to be effective, the components of the system
are preferably sealed to the lung. Accordingly, the localized pleurodesis
chemical delivery system of the present invention is utilized to create a
pleurodesis in the area or areas of the lung that are most collaterally
ventilated.
Various chemicals, agents andlor compounds may be delivered via catheter
based delivery systems or via implantable medical devices.
Brief Description of the Drawings
The foregoing and other features and advantages of the invention will be
apparent from the following, more particular description of preferred
embodiments of the invention, as illustrated in the accompanying drawings.
Figure 1 is a diagrammatic representation of a first exemplary
embodiment of the long term oxygen therapy system in accordance with the
present invention.
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CA 02466636 2004-05-07
Figure 2 is a diagrammatic representation of a first exemplary
embodiment of a sealing device utilized in conjunction with the long term
oxygen therapy system of the present invention.
Figure 3 is a diagrammatic representation of a second exemplary
embodiment of a sealing device utilized in conjunction with the long term
oxygen therapy system of the present invention.
Figure 4 is a diagrammatic representation of a third exemplary
embodiment of a sealing device utilized in conjunction with the long term
oxygen therapy system of the present invention.
Figure 5 is a diagrammatic representation of a fourth exemplary
embodiment of a sealing device utilized in conjunction with the long term
oxygen therapy system of the present invention.
Figure 6 is a diagrammatic representation of a second exemplary
embodiment of the long term oxygen therapy system in accordance with the
present invention.
Figure 7 is a diagrammatic representation of a first exemplary
embodiment of a collateral ventilation bypass trap system in accordance with
the present invention.
Figure 8 is a diagrammatic representation of a first exemplary
embodiment of a localized pleurodesis chemical delivery system.
Figure 9 is a diagrammatic representation of a second exemplary
embodiment of a localized pleurodesis chemical delivery system.
Detailed Description of the Preferred Embodiments
Air typically enters the mammalian body through the nostrils and flows
into the nasal cavities. As the air passes through the nostrils and nasal
9
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cavities, it is filtered, moistened and raised or lowered to approximately
body
temperature. ~ The back of the nasal cavities is continuous with the pharynx
(throat region); therefore, air may reach the pharynx from the nasal cavities
or
from the mouth. Accordingly, if equipped, the mammal may breath through its
nose or mouth. Generally air from the mouth is not as filtered or temperature
regulated as air from the nostrils. The air in the pharynx flows from an
opening
in the floor of the pharynx and into the larynx (voice box). The epiglottis
automatically closes off the larynx during swallowing so that solids and/or
liquids enter the esophagus rather than the lower air passageways or airways.
IO From the larynx, the air passes into the trachea, which divides into two
branches, referred to as the bronchi. The bronchi are connected to the lungs.
The lungs are large, paired, spongy, elastic organs, which are positioned
in the thoracic cavity. The lungs are in contact with thie walls of the
thoracic
I S cavity. In humans, the right lung comprises three lobes and the left lung
comprises two lobes. Lungs are paired in all mammals, but the number of
lobes or sections of lungs varies from mammal to mammal. Healthy lungs, as
discussed below, have a tremendous surface area for gaslair exchange. Both
the left and right lung is covered with a pleural membrane. Essentially, the
20 pleural membrane around each lung forms a continuous sac that encloses the
lung. A pleural membrane also forms a lining for the thoracic cavity: The
space between the pleural membrane forming the lining of the thoracic cavity
and the pleural membranes enclosing the lungs is referred to as the pleural
cavity. The pleural cavity comprises a film of fluid that serves as a
lubricant
25 between the lungs and the chest wall.
in the lungs, the bronchi branch into a multiplicity of smaller vessels
referred to as bronchioles. Typically, there are more than one million
bronchioles in each lung. Each bronchiole ends in a cluster of extremely small
30 air sacs referred to as alveoli. An extremely thin, single layer of
epithelial cells
lining each alveolus wall and an extremely thin; single layer of epithelial
cells
lining the capillary walls separate the air/gas in the alveolus from the
blood.
Oxygen molecules in higher concentration pass by simple diffusion through the
CA 02466636 2004-05-07
two thin layers from the alveoli into the blood in the pulmonary capillaries.
Simultaneously, carbon dioxide molecules in higher concentration pass by
simple diffusion through the two thin layers from the blood in the pulmonary
capillaries into the alveoli-
Breathing is a mechanical process involving inspiration and expiration.
The thoracic cavity is normally a closed system and air cannot enter or leave
the lungs except through the trachea. If the chest wall is somehow
compromised and airlgas enters the pleural cavity, the lungs will typically
collapse. When the volume of the thoracic cavity is increased by the
contraction of the diaphragm, the volume of the lungs is also increased: As
the
volume of the lungs increase, the pressure of the air in the lungs falls
slightly
below the pressure of the air external to the body (ambient air pressure).
Accordingly, as a result of this slight pressure differential, external or
ambient
air flows through the respiratory passageways described above and fills the
lungs until the pressure equalizes. This process is inspiration. When the
diaphragm is relaxed, the volume of the thoracic cavity decreases, which in
turn decreases the volume of the Lungs. As the volume of the lungs decrease,
the pressure of the air in the lungs rises slightly above the pressure of the
air
external to the body. Accordingly, as a result of this slight pressure
differential;
the air in the alveoli is expelled through the respiratory passageways until
the
pressure equalizes. This process is expiration.
Continued insult to the respiratory system may result in various
diseases, for example, chronic obstructive pulmonary disease. Chronic
obstructive pulmonary disease is a persistent obstruction of the airways
caused
by chronic bronchitis and pulmonary emphysema. In the United States alone,
approximately fourteen million people suffer from some form of chronic
obstructive pulmonary disease and it is in the top ten Leading causes of death
Chronic bronchitis and acute bronchitis share certain similar
characteristics; however, they are distinct diseases. both chronic and acute
bronchitis involve inflammation and constriction of the bronchial tubes and
the
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CA 02466636 2004-05-07
bronchioles; however, acute bronchitis is generally associated with a viral
andlor bacterial infection and its duration is typically much shorter than
chronic
bronchitis. In chronic bronchitis; the bronchial tubes secrete tob much mucus
as part of the body's defensive mechanisms to inhaled foreign substances.
Mucus membranes comprising ciliated cells (hair like structures) line the
trachea and bronchi. The ciliated cells or cilia continuously push or sweep
the
mucus secreted from the mucus membranes in a direction,away from the lungs
and into the pharynx, where it is periodically swallowed. This sweeping action
of the cilia functions to keep foreign matter from reaching the lungs. Foreign
matter that is not filtered by the nose and larynx, as described above,
becomes
trapped in the mucus and is propelled by the cilia into the pharynx. When too
much mucus is secreted, the ciliated cells may become damaged, leading to a
decrease in the efficiency of the cilia to sweep the bronchial tubes and
trachea
of the mucus containing the foreign matter. This in turn causes the
bronchioles
to become constricted and inflamed and the individual becomes short of
breath. In addition, the individual will develop a chronic cough as a means of
attempting to clear the airways of excess mucus.
Individuals who suffer from chronic bronchitis may develop pulmonary
emphysema. Pulmonary emphysema is a disease in which the alveoli walls,
which are normally fairly rigid structures, are destroyed. The destruction of
the
alveoli walls is irreversible. Pulmonary emphysema may be caused by a
number of factors, including chronic bronchitis, long term exposure to inhaled
irritants, e.g. air pollution, which damage the cilia, enzyme deficiencies and
other pathological conditions. In pulmonary emphysema, the alveoli of the
lungs lose their elasticity, and eventually the walls between adjacent alveoli
are
destroyed. Accordingly, as more and more alveoli walls are lost, the air
exchange (oxygen and carbon dioxide) surface area of the lungs is reduced
until air exchange becomes seriously impaired. The combination of mucus
hypersecretion and dynamic airway compression are mechanisms of airflow
limitation in chronic obstructive pulmonary disease. Dynamic airway
compression results from the loss of tethering forces exerted on the airway
due
to the reduction in lung tissue elasticity. Mucus hypersecretion is described
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CA 02466636 2004-05-07
above with respect to bronchitis. In other words, the breakdown of lung tissue
leads to the reduced ability of the lungs to recoil and the loss of radial
support
of the ainrvays. Consequently, the loss of elastic recoil of the rung tissue
contributes to the inability of individuals to exhale completely. The loss of
radial support of the airways also allows a collapsing phenomenon to occur
during the expiratory phase of breathing. This collapsing phenomenon also
intensifies the inability for individuals to exhale completely. As the
inability to
exhale completely increases, residual volume in the lungs also increases. This
then causes the lung to establish in a hyperinflated state where an individual
can only take short shallow breaths. Essentially, air is not effectively
expelled
and stale air accumulates in the lungs. Once the stale air accumulates in the
lungs, the individual is deprived of oxygen. There is no cure for pulmonary
emphysema, only various treatments, including exercise, drug therapy, such as
bronchodilating agents, lung volume reduction surgery and long term oxygen
therapy.
As described above, long term oxygen therapy is widely accepted as the
standard treatment for hypoxia caused by chronic obstructive pulmonary
disease. Typically, oxygen therapy is prescribed using a nasal cannula, There
20' are disadvantages associated with using the nasal cannula. One
disadvantage
associated with utilizing nasal cannula is the significant loss of oxygen
between
the cannula and the nose, which in tum equates to more frequent changes in
the oxygen source, or higher energy requirements to generate more oxygen.
Another disadvantage associated with utilizing nasal cannuia is the fact that
the
cannulas may cause the nasal passages to become dry, cracked and sore.
Transtracheal oxygen therapy has become a viable alternative to long
term oxygen therapy. Transtracheal oxygen therapy delivers oxygen directly to
the lungs using a catheter that is placed through and down the Trachea. Due to
the direct nature of the oxygen delivery, a number of advantages are achieved.
These advantages include lower oxygen requirements due to greater
efficiency, increased mobility, greater exercise capability and improved self
image.
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The long term oxygen therapy system and method of the present
invention may be utilized to deliver oxygen directly into the lung tissue in
order
to optimize oxygen transfer efficiency in the lungs. In other words, improved
efficiency may be achieved if oxygen were to be delivered directly into the
alveolar tissue in the lungs. In emphysema, alveoli walls are destroyed;
thereby causing a decrease in air exchange surface area. As more alveoli
walls are destroyed, collateral ventilation resistance is lowered. In other
words,
pulmonary emphysema causes an increase in collateral ventilation and to a
certain extent, chronic bronchitis also causes an increase in collateral
ventilation. Essentially, in an emphysematous lung, the communicating flow of
air between neighboring air sacs (alveoli), knoHrn as collateral ventilation,
is
much more prevalent as compared to a normal lung. Since air cannot be
expelled from the native airways due to the loss of tissue elastic recoil and
radial support of the airways (dynamic collapse during exhalation), the
increase
in collateral ventilation does not significantly assist an individual in
breathing.
The individual develops dsypnea. Accordingly, if it can be determined where
collateral ventilation is occurring, then the diseased lung tissue may be
isolated
and the oxygen delivered to this precise location or locations. Various
methods
may be utilized to determine the diseased tissue locations, for example,
computerized axial tomography or CAT scans, magnetic resonance imaging or
MRI, positron emission tomograph or PET, andlor standard X-ray imaging.
Once the diseased tissue is located, pressurized oxygen may be directly
delivered to these diseased areas and mare effectively and efficiently forced
into the lung tissue for air exchange.
Figure 1 illustrates a first exemplary long term oxygen therapy system
100. The system 100 comprises an oxygen source 102, an oxygen carrying
conduit 104 and a one-way valve 106. The oxygen source 702 may comprise
any suitable device for supplying filtered oxygen under adjustably regulated
pressures and flow rates, including pressurized oxygen tanks, liquid oxygen
reservoirs, oxygen concentrators and the associated devices for controlling
pressure and flow rate e.g. regulators. The oxygen carrying conduit 104 may
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CA 02466636 2004-05-07
comprise any suitable biocompatible tubing having a high resistance to
damage caused by continuous oxygen exposure. The oxygen carrying conduit
104 comprises tubing having an inside diameter in the range from about 1116
inch to about 112 inch and more preferably from about 1/8 inch to about
S 114 inch. The one-way valve 106 may comprise any suitable, in-line
mechanical valve which allows oxygen to flow into the lungs 108 through the
oxygen carrying conduit 104, but not from the lungs 1 ~8 back into the oxygen
source 102, For example, a simple check valve may be utilized. As illustrated
in Figure 1, the oxygen carrying conduit 104 passes through the lung 108 at
the site determined to have the highest degree of collateral ventilation.
The exemplary system 100 described above may be modified in a
number of ways, including the use of an in-line filter. In this exemplary
embodiment, both oxygen and air may flow through the system. In other
words, during inhalation, oxygen is delivered to the lungs through the oxygen
carrying conduit 104 and during exhalation, air from the lungs flow through
the
oxygen carrying conduit 104. The in-line filter would trap mucus and other
contaminants, thereby preventing a blockage in the oxygen source 102. In this
exemplary embodiment, no valve 106 would be utilized. The flow of oxygen
into the lungs and the flow of air from the lungs is based on pressure
differentials.
In order for the exemplary long term oxygen therapy system 100 to
function, an air-tight seal is preferably maintained where the oxygen carrying
conduit 104 passes through the thoracic cavity and lung. This seal is
maintained in order to sustain the inflation/functionality of the lungs. If
the seal
is breached, air can enter the cavity and cause the lungs to collapse as
described above.
A method to create this seal comprises forming adhesions between the
visceral pleura of the lung and the inner waH of the thoracic cavity. This may
be achieved using either chemical methods, including irritants such as
Doxycycline and/or Bleomycin; surgical methods, including pleurectomy or
CA 02466636 2004-05-07
horoscope talc pleurodesis, or radiotherapy methods, including radioactive
gold
or external radiation. All of these methods are known in the relevant art for
creating pleurodesis. With a seal created at the site for the ventilation
bypass,
an intervention may be safely pertormed without the danger of creating a
pneumothorax of the lung.
Similarly to ostomy pouches or bags, the oxygen carrying conduit 104
may be sealed to the skin at the site of the ventilation bypass. In one
exemplary embodiment, illustrated in Figure 2, the oxygen carrying conduit 104
may be sealedto the skin of the thoracic wail utilizing an adhesive. As
illustrated, the oxygen carrying conduit 104 comprises a flange 200 having a
biocompatible adhesive coating on the skin contacting surtace. The
biocompatible adhesive would provide a fluid tight seal between the flange 200
and the skin or epidermis of the thoracic wall. In a preferred embodiment, the
biocompatible adhesive provides a temporary fluid tight seal such that the
oxygen carrying conduit 104 may be disconnected from the ventilation bypass
site. This would allow for the site to be cleaned and for the long term oxygen
therapy system 100 to undergo periodic maintenance.
Figure 3 illustrates another exemplary embodirr~ent for sealing the
oxygen carrying conduit 104 to the skin of the thoracic wall at the site of
the
ventilation bypass. In this exemplary embodiment, a coupling plate 300 is
sealed to the skin at, the site of the ventilation bypass by a biocompatible
. adhesive coating or any other suitable means. The oxygen carrying conduit
104 is then connected to the coupling plate 300 by any suitable means,
including threaded couplings and locking rings. The exemplary embodiment
also allows for cleaning of the site and maintenance of the system 100.
Figure 4 illustrates yet another exemplary embodiment for sealing the
oxygen carrying conduit 104 to the skin of the thoracic wall at the site of
the
ventilation bypass. !n this exemplary embodiment, balloon flanges 400 may be
utilized to create the seal. The balloon flanges 400 may be attached to the
oxygen carrying conduit 104 such that in the deflated state, the oxygen
carrying
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CA 02466636 2004-05-07
conduit 104 and one of the balloon flanges passes through the ventilation
bypass anastomosis. The balloon flanges 400 are spaced apart a sufficient
distance such that the balloon flanges remain on opposite sides of the
thoracic
wall. When inflated, the balloons expand and form a f6uid tight seal by
sandwiching the thoracic wall. Once again, this exemplary embodiment allows
for easy removal of the oxygen carrying conduit 104.
Figure 5 illustrates yet another exemplary embodiment for sealing the
oxygen carrying conduit 104 to the skin of the thoracic wail at the site of
the
ventilation bypass. In this exemplary embodiment, a single balloon flange 500
is utilized in combination with a fixed flange 502. The balloon flange 500 is
connected to the oxygen carrying conduit 104 in the same manner as
described above. In this exemplary embodiment, the balloon flange 500; when
inflated, forms the fluid tight seal. The fixed flange 502, which is
maintained
against the skin of the thoracic wall; provides the structural support against
which the balloon exerts pressure to form the seal.
If an individual has difficulty exhaling and requires additional oxygen,
collateral ventilation bypass may be combined with direct oxygen therapy.
Figure 6 illustrates an exemplary embodiment of a collateral ventilation
bypassldirect oxygen therapy system 600. The system 600 comprises an
oxygen source 602, an oxygen carrying conduit 604 having two branches 606
and 608, and a control valve 610. The oxygen source 602 and oxygen carrying
conduit 604 may comprise components similar to the above-described
exemplary embodiment illustrated in Figure 1. In this exemplary embodiment,
when the individual inhales, the valve 610 is open and oxygen flows into the
lung 612 and into the bronchial tube 614. In an alternate exemplary
embodiment, the branch 608 may be connected to the trachea 616.
Accordingly, during inhalation oxygen flows to the diseased site in the lung
or
lungs and to other parts of the lung through the normal bronchial passages.
During exhalation, the valve 610 is closed so that no oxygen is delivered and
air in the diseased pprtion of the lung may flow from the lung 612, through
one
branch 606 and into the second branch 608 and finally into the bronchial tube
17
CA 02466636 2004-05-07
616. In this manner, stale air is removed and oxygen is directly delivered.
Once again, as described above, the flow of oxygen and air is regulated by
simple pressure differentials.
The connection and sealing of the oxygen carrying conduit 604 and
branches 606, 608 to the lung 612 and bronchial tube 614 may be made in a
manner similar to that described above.
The above-described long term oxygen therapy system may be utilized
to effectively treat hypoxia caused by chronic obstructive pulmonary disease;
however, other means may be desirable to treat other aspects of the disease.
As set forth above, emphysema is distinguished as irreversible damage to lung
tissue. The breakdown of lung tissue leads to the reduced ability for the
lungs
to recoil. The tissue breakdown also leads to the loss df radial support of
the
native airways. Consequently, the loss of elastic recoil of the lung tissue
contributes to the inability for individuals with emphysema to exhale
completely. The loss of radial support of the native airways also allows a
collapsing phenomenon to occur during the expiratory phase of breathing. This
collapsing phenomenon also intensifies the inability for individuals to exhale
completely. As the inability to exhale increases, residual volume in the lungs
also increases. This then causes the lung to establish in a hyperinflated
state
wherein an individual can only take short shallow breaths.
The collateral ventilation bypass trap system of the present invention
utilizes the above-described collateral ventilation phenomenon to increase the
expiratory flow from a diseased lung or lungs, thereby treating another aspect
of chronic obstructive pulmonary disease. Essentially, the most collaterally
ventilated area of the lung or lungs is determined utilizing the scanning
techniques described above. Once this area or areas are located, a conduit or
conduits are positioned in a passage or passages that access the outer pleural
layer of the diseased lung or lungs. The conduit or conduits utilize the
collateral ventilation of the lung or lungs and allows the entrapped air to
bypass
18
CA 02466636 2004-05-07
the native airways and be expelled to a containment system outside of the
body.
Figure .7 illustrates a first exemplary collateral ventilation bypass trap
system 700. The system 700 comprises a trap 702, an air carrying conduit 704
and a filterlone-way valve 706. The air carrying conduit 704 creates a fluid
communication between an individual's lung 708 and the trap 702 through the
filter/one-way valve 706. It is important to note that although a single
conduif
704 is illustrated, multiple conduits may be utilized. in each lung 708 if it
is
determined that there are more than one area of high collateral ventilation.
The trap 702 may comprise any suitable device for collecting discharge
from the individual's lung or lungs 708. Essentially, the trap 702 is simply a
containment vessel for temporarily storing discharge from the lungs, for
example, mucous and other fluids that may accumulate in the lungs. The trap
702 may comprise any suitable shape and may be formed from any suitable
metallic or non-metallic materials. Preferably, the trap 702 should be formed
from a lightweight, non-corrosive material. In addition, the trap 702 should
be
designed in such a manner as to allow for effective and efficient cleaning. In
one exemplary embodiment, the trap 702 may comprise disposable liners that
may be removed when the trap 702 is full: The trap 702 may be formed from a
transparent material or comprise an indicator window so that it maybe easily
determined when the trap 702 should be emptied or cleaned. A lightweight
trap 702 increases the patient's mobility.
The filterlone-way valve 706 may be attached to the trap 702 by any
suitable means, including threaded fittings or compression type fittings
commonly utilized in compressor connections. The filterlone-way valve 706
serves a number of functions. The filter/one-way valve 706 allows the air from
the individual's lung or lungs 708 to exit the trap 702 while maintaining the
fluid
discharge and solid particulate matter in the trap 702. This filter/one-way
valve
706 would essentially maintain the pressure in the trap 702 below that of the
pressure inside the individual's lung or lungs 708 so'that the flow of air
from the
19
CA 02466636 2004-05-07
lungs 708 to the trap 702 is maintained in this one direction. The filter
portion
of the filterlone-way valve 706 may be designed to capture particulate matter
of
a particular size which is suspended in the air, but allows the clean air to
pass
therethrough and be vented to the ambient environment. The filter portion may
also be designed in such a manner as to reduce the moisture content of the
exhaled air.
The air carrying conduit 704 connects the trap 702 to the sung or lungs
708 of the patient through the filter/one-way valve 706. The air carrying
conduit 704 may comprise any suitable biocompatible tubing having a
resistance to the gases contained in air. The air carrying conduit 704
comprises tubing having an inside diameter in the range from about 1/16 inch
to about 1/2 inch, and more preferably from about 118 inch to about 1/4 inch.
The filterlone-way valve 706 may comprise any suitable valve which allows air
to flow from the lung or lungs 708 through the air carrying conduit 704, but
not
from the trap 702 back to the lungs 708. For example, a simple check valve
may be utilized. The air carrying conduit 704 may be connected to the
filterlone-way valve 706 by any suitable means. Preferably, a quick release
mechanism is utilized so that the trap may be easily removed for maintenance.
As illustrated in Figure 7, the air carrying conduit 704 passes through the
lung
708 at the site determined to have the highest degree of collateral
ventilation.
If more than one site is determined, multiple air carrying conduits 704 may be
utilized. The connection of multiple air carrying conduits 704 to the
filterlone-
way valve 706 may be accomplished by any suitable means, including an
octopus device similar to that utilized in scuba diving regulators.
The air carrying conduit 704 is preferably able to withstand and resist
collapsing once in place. Since air will travel through the conduit 704, it
the
conduit is crushed and unable to recover; the effectiveness of the system is
diminished. Accordingly, a crush recoverable material may be incorporated
into the air carrying conduit 704 in order to make it crush recoverable. Any
number of suitable materials may be utilized. For example; Nitinol
incorporated
CA 02466636 2004-05-07
into the conduit 704 will give the conduit collapse resistance and collapse
recovery properties.
Expandable features at the end of the conduit T04 may be used to aid in
maintaining contact and sealing the conduit 704 to the lung pleura. Nitinol
incorporated into the conduit 704 will provide the ability to deliver the
conduit
704 in a compressed state and then deployed in -an expanded state to secure it
in place. Shoulders at the end of the conduit may also provide a mechanical
stop for insertion and an area for an adhesivelsealant to join as described in
detail subsequently.
In order for the exemplary collateral ventilation bypass trap system 700
to function, an air-tight seal is preferably maintained where the air carrying
conduit 704 passes through the thoracic cavity and lungs 70>3. This seal is
maintained in order to sustain the infiationlfunctionality of the lungs. If
the seal
is breached, air can enter the cavity and cause the lungs to collapse. One
exemplary method for creating the seal comprises forming adhesions between
the visceral pleura of the lung and the inner wall of the thoracic cavity.
This
may be achieved using either chemical methods, including irritants such as
Doxycycline and/or Bleomycin, surgical methods, including pleurectorny or
thorascopic talc pleurodesis, or radiotherapy methods, including radioactive
gold or external radiation. All of these methods are known in the relevant art
for creating pleurodesis. In another alternate exemplary embodiment, a sealed
joint between the air carrying conduit 704 and the outer pleural layer
includes
using various glues to help with the adhesionlsealing of the air carrying
conduit
704. Currently, Focal Inc. markets a sealant available under the tradename
FocaI/Seal-L which is indicated for use on a lung for sealing purposes.
FocaIISeaI-L is activated by light in order to cure the sealant. Another seal
available under the tradename Thorex, which is manufactured by Surgical
Sealants Inc., is currently conducting a clinical trial for lung sealing
indications.
Thorex is a two-part sealant that has a set curing time after the two parts
are
mixed:
21
CA 02466636 2004-05-07
The creation of the opening in the chest cavity may be accomplished in
a number of ways. For example, the procedure may be accomplished using an
open chest procedure, aternotomy or thoracotomy. Alternately; the procedure
may be accomplished using a laproscopic technique, which is less invasive.
Regardless of the procedure utilized, the seal should be established while the
lung is at least partially inflated in order to maintain a solid adhesive
surface.
The opening may there be made after the joint has been adequately created
between the conduit component and the lung pleural surtace. The opening
should be adequate in cross-sectional area in order to provide sufficient
decompression of the hyperinflated lung. This opening, as stated above, may
be created using a number of different techniques such as cutting, piercing,
dilating, blunt dissection, radio frequency energy, ultrasonic energy,
microwave
energy, or cryoblative energy.
The air carrying conduit 704 may be sealed to the skin at the site by any
of the means and methods described above with respect to the oxygen
carrying conduit 704 and illustrated in Figures 2 through 5.
In operation, when an individual exhales, the pressure in the lungs is
greater than the pressure in the trap 702. Accordingly, the air in the highly
collaterilized areas of the lung will travel through the air carrying conduit
704 to
the trap 702. This operation will allow the individual to more easily and
completely exhale.
In the above-described exemplary apparatus and procedure for
increasing expiratory flow from a diseased lung using the phenomenon of
collateral ventilation, there willbe an optimal location to penetrate the
outer
pleura of the lung to access the most collaterally ventilated area or area's
of the
lung. As described above, there are a variety of techniques to locate the most
collaterally ventilated area or areas of the lungs. Since a device or
component
of the apparatus functions to allow the air entrapped in the lung to bypass
the
native airways and be expelled outside of the body, it is particularly
advantageous to provide an air-tight seal of the parietal (thoracic wall) and
visceral (lung) pleurae. If a proper air-tight seal is not created between the
22
CA 02466636 2004-05-07
device, parietal and visceral pleurae, then a pneumothorax (collapsed lung)
may occur. Essentially, in any circumstance where the lung is punctured and a
device inserted, an air-tight seal should preferably be maintained.
One way to achieve an air-tight seal is through pleurodesis, i.e. an
obliteration of the pleural space. There are a number of pleurodesis methods,
including chemical, surgical and radiological. In chemical pleurodesis, an
agent such as tetracycline, doxycycline, bleomycin or nitrogen mustard may be
utilized. In surgical pleurodesis, a pleurectomy or a thorascopic talc
procedure
may be performed. In radiological procedures, radioactive gold or external
radiation may be utilized. In the present invention, chemical pleurodesis is
utilized.
Exemplary devices and methods for delivering a chemicals) or agents)
in a localized manner for ensuring a proper air-tight seal ofahe above=
described apparatus is described below. The chemical(s), agents) andlor
compounds) are used to create a pleurodesis between the parietal and
visceral pleura so that a component of the apparatus may penetrate though
the particular area and not result in a pneumothorax: There are a number of
chemical(s), agents) and/or compounds) that may be utilized to create a
pleurodesis in the pleural space. The chemical(s), agents) andlor
compounds) include talc, tetracycline, doxycycline, bleomycin and
minocycline.
In one exemplary embodiment, a modified drug delivery catheter may be
utilized to deliver chemicai(s), agents) and/or compounds) to a localized area
for creating a pleurodesis in that area. in this exemplary embodiment, the
pleurodesis is formed and then the conduit 704; as illustrated in Figure 7, is
positioned in the lung 708 through the area of the pleurodesis. The drug
delivery catheter provides a minimally invasive means for crating a localized
pleurodesis. Referring to Figure 8, there is illustrated an exemplary
embodiment of a drug delivery catheter that may be utilized in accordance with
the present invention. Any number of drug delivery catheters may be utilized.
23
CA 02466636 2004-05-07
In addition, the distal tip of the catheter may comprise any suitable size,
shape
or configuration thereby enabling the formation of a pleurodesis having any
size, shape or configuration.
As illustrated in Figure 8, the catheter 800 is inserted into the patient
such that the distal end 802 is positioned in the pleural space 804 between
the
thoracic wall 800 and the lung 808. In the illustrated e~cemplary embodiment,
the distal end 802 of the catheter 800 comprises a substantially circular
shape
that would allow the chemical(s), agents) andlor compounds) to be released
towards the inner diameter of the substantially circular shape as indicated by
arrows 810. The distal end 802 of the catheter 800 comprising a plurality of
holes or openings 812 through which the chemical(s), agents) and/or
compounds) are released. As stated above, the distal end 802 may comprise
any suitable size, shape or configuration. Once the chemical(s); agents)
andlor compounds) are delivered, the catheter 800 may be removed to allow
for implantation of the conduit 704 (Figure 7). Alternately, the catheter 800
may be utilized to facilitate delivery of the conduit 704:
The distal end or tip 802 of the catheter 800 should preferably maintain
its desired size, shape andlor configuration once deployed in the pleural
space.
This may be accomplished in a number of ways. For example, the material
forming the distal end 802 of the catheter 800 may be selected such that it
has
a certain degree of flexibility for insertion of the catheter 800 and a
certain
degree of shape memory such that it resumes its original or programmed
shape once deployed. Any number of biocompatible polymers with these
properties may be utilized. In an alternate embodiment, another material may
be utilized. For example, a metallic material having shape memory
characteristics may be integrated into the distal end 802 of the catheter 800.
This metallic material may include nitinol or stainless steel. In addition,
the
metallic material may be radiopaque or comprise radiopaque markers. By
having a radiopaque material or radiopaque markers, the catheter 800 may be
viewed under x-ray fluoroscopy and aid in determining when the catheter 800 is
at the location of the highest collateral ventilation
24
CA 02466636 2004-05-07
in another alternate exemplary embodiment, a local drug delivery device
may be utilized to deliver the pieurodesis chemical(s), agents) andlor
compound(s). !n this exemplary embodiment; the pleurodesis is farmed and
then the conduit 704, as illustrated in Figure 7, is positioned in the lung
708
through the pieurodesis. In this exemplary embodiment, chemical(s), agents)
andlor compounds) may be affixed town impiantable medical device. The
medics! device is then implanted in the pleural cavity at a particular site
and the
chemical(s), agents) and/or compounds} are released therefrom to form or
create the pleurodesis.
Any of the above-described chemical(s), agents) andlor compounds)
may be affixed to the medical device. The chemical(s), agents) and/or
compounds) may be affixed to the medical device in any suitable manner. For
example, the chemical(s), agents) andlor compound{s} may be coated on the
device utilizing any number of well known techniques including, pin coating,
spraying or dipping, they may be incorporated into a polymeric matrix that is
affixed to the surface of the medical device, they may be impregnated into the
outer surface of the medical device, they may be incorporated into holes or
chambers in fhe medical device, they may be coated onto tha surtace of the
medical device and then coated with a polymeric layer that acts as a diffusion
barrier for controlled release of the chemical(s), agents) and/or compound{s),
they may be incorporated directly into the material forming the medical
device,
or any combination of the above-described techniques. In another alternate
embodiment, the medical device may be formed from a.biodegradabie material
which elutes the chemical(s), agent{s) andlor compounds} as the device
degrades. .
The implantable medical device may comprise any suitable size, shape
andlor configuration, and may be formed using any suitable biocompatibie
material. Figure 9 illustrates one exemplary embodiment of an implantable
medical device 900. In this embodiment, the impiantable medical device 900
comprises a substantially cylindrical disk 900. The disk 900 is positioned in
the
CA 02466636 2004-05-07
pleural space 902 between the thoracic wall 904 and the lung 906. Once in
position, the disk 900 elutes or otherwise releases the chemical(s), agents)
andlor compounds) that form the pleurodesis. The release rate may be
precisely controlled by using any of the various techniques described above,
for example, a polymeric diffusion barrier: Also, as stated above, the disk
900
rnay be formed from a biodegradable material that elutes the chemical(s),
agents) andlor compounds) as the disk 900 itself disintegrates or dissolves.
Depending upon the material utilized in the construction of the disk.900, a
non-
biodegradable disk 900 may or may not require removal from the pleural cavity
902 once the pleurodesis is formed. For example, it may be desirable that the
disk 900 is a permanent implant that becomes integral with the pleurodesis.
As described in the previous exemplary embodiment, the disk 900 may
comprise a radiopaque marker or be formed from a radiopaque material. The
I S radiopaque marker or material allows the disk 900 to be seen under
fluoroscopy and then positioned accurately.
In yet another alternate exemplary embodiment, the fluid characteristics
of the chemical(s), agents) andlor compounds) may be altered. For example,
the chemical(s), agents) andlor compounds) may be made more viscous.
With a more viscous chemical agent andlor compound, there would be less
chance of the chemical, agent andlor compound moving from the desired
location in the pleural space. The chemical(s), agents) andlor compounds)
may also comprise radiopaque constituents. Making the chemical(s), agents)
and/or compounds radiopaque would allow the confirmation of the location of
the chemical(s), agents) a.nd/or compounds) with regard to the optimal
location of collateral ventilation.
The chemical(s), agents) andlor compounds) as modified above may
be utilized in conjunction with standard chemical pleurodesis devices and
processes or in conjunction with the exemplary embodiments set forth above.
26
CA 02466636 2004-05-07
Although shown and described is what is believed to be the most
practical and preferred embodiments, it is apparent that departures from
specific designs and methods described and shown will suggest themselves to
those skilled in the art and may be used without departing from the spirit and
scope of the invention. The present invention is not restricted to the
particular
constructions described and illustrated, but should be constructed to cohere
with all modifications that may fall within the scope of the appended claims.
27
