Note: Descriptions are shown in the official language in which they were submitted.
CA 02469523 2004-06-03
LUNG REDUCTION SYSTEM
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Provisional Application Number
60/475,291 filed June 3, 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
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 containment/trap device. The present invention also relates to a
collateral ventilation bypass system that utilizes the trachea for expelling
trapped air rather than a containment/trap device. The present invention also
relates to a device and methodology to assist in pulmonary decompression and
non-surgical/resection lung volume reduction. 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's, it has been determined that
long-term continuous oxygen therapy is beneficial in the treatment of
hypoxemic patients 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.
CA 02469523 2004-06-03
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.
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 Brummelkamp; 3,511,243 to Toy; 3,556,103 to
Calhoun; 2,991,787 to Shelden, et al; 3,688,773 to Weiss; 3,817,250 to Weiss,
et al.; and 3,916,903 to Pozzi.
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Although tracheotomy tubes are satisfactory for 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
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
mm outside diameter in adults. They are normally inserted in an operating
room as a surgical procedure or during emergency situations, through the
10 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.
15 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 other tracheotomy 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 stemal 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
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CA 02469523 2004-06-03
. 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
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.
Diseases associated with chronic obstructive pulmonary disease include
chronic bronchitis and emphysema. One aspect of an emphysematous lung is
that the communicating flow 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.
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CA 02469523 2004-06-03
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 reasons 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. In
addition,
there exists a need for a minimally invasive means for removing trapped air
from the lung or lungs that would allow healthy lung tissue to better
ventilate.
There also exists a need for a minimally invasive means for allowing trapped
air from the lung or lungs to escape that would allow healthy lung tissue to
better ventilate.
Summary of the Invention
The present invention overcomes the disadvantages associated with
treating chronic obstructive pulmonary disease, as briefly described above, by
utilizing the phenomenon of collateral ventilation to increase the expiratory
flow
from a diseased lung. The present invention also provides a means for
assisting in or facilitating pulmonary decompression to compress the diseased
area or area of the lung or lungs to a smaller volume.
In accordance with a first aspect, the present invention is directed to a
lung reduction device. The device comprising at least one first member in
fluid
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communication, at a predetermine site, within a lung of a patient, a sealing
device for establishing an airtight seal between the at least one first member
and the lung, and a second member connected to the at least one first
member, the second member comprising an apparatus for allowing air from the
lung of the patient to vent to an area external of the lung and preventing air
from an area external of the lung from re-entering the lung through the
device.
In accordance with a second aspect, the present invention is directed to
a lung reduction device. The device comprising at least one first member in
fluid communication, at a predetermined site, within a lung of a patient, a
first
sealing device for establishing an airtight seal between the at least one
first
member and the lung, a second member connected to and in fluid
communication with the at least one first member, the second member
comprising an apparatus for allowing air from the lung of the patient to vent
to
the ambient environment, and preventing air from the ambient environment
from re-entering the lung through the device, the second member including a
section positioned external of the body of the patient, and a second sealing
device for sealing the section positioned external of the body of the patient
to
the body.
In accordance with a third aspect, the present invention is directed to a
method for reducing the volume of a hyperinflated portion of a lung of a
patient.
The device comprising determining a site of hyperinflation in a patient's
lung,
and allowing air from the hyperinflated portion of the lung to vent through a
device to the ambient environment and preventing air from the ambient
environment from re-entering the lung through the device.
The long-term oxygen therapy system of the present invention delivers
oxygen directly to diseased sites in a patient's lungs. Long 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
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CA 02469523 2004-06-03
are destroyed. As more and more alveoli walls are lost, the air exchange
surface 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, and/or standard X-ray imaging. Once the location or
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 turn reduces the patient's medical costs. The system
also allows for improved self-image, improved mobility, greater exercise
capability and is easily maintained.
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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
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 allow the entrapped air to
bypass
the native airways and be expelled to a containment system outside of the
body.
In an alternate embodiment, the trachea, or other proximal airways,
including the bronchus, may be utilized for expelling trapped air rather than
a
containment/trap device.
The pulmonary decompression device of the present invention removes
air from hyperinflated regions of the lung or lungs of a patient by creating a
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CA 02469523 2004-06-03
slight pressure differential between the internal volume of the lung and a
location external of the lung. An apparatus such as a vacuum fan or pump
creates the pressure differential, thereby removing the trapped air and
reducing
the volume of diseased tissue.
The lung reduction device of the present invention allows trapped air
from hyperinflated regions of the lung or lungs of a patient to vent to the
external environment through a one-way valve. The valve prevents air from
flowing back into the lung or lungs.
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 and/or 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 tong term oxygen therapy system in accordance with the
present invention.
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.
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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 tong 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 second exemplary
embodiment of a collateral ventilation bypass system in accordance with the
present invention.
Figure 9 is a diagrammatic representation of a third exemplary
embodiment of a collateral ventilation bypass system in accordance with the
present invention.
Figure 10 is a diagrammatic representation of a fourth exemplary
embodiment of a collateral ventilation bypass system in accordance with the
present invention.
Figure 11 is a diagrammatic representation of an exemplary pulmonary
decompression device in accordance with the present invention.
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Figures 12a and 12b are diagrammatic representations of the effects on
lung volume in accordance with the present invention.
Figures 13a and 13b are diagrammatic representations of the effects on
lung volume reduction utilizing the lung reduction system in accordance with
the present invention.
Figure 14 is a diagrammatic representation of a first exemplary
embodiment of a localized pleurodesis chemical delivery system.
Figure 15 is a diagrammatic representation of a second exemplary
embodiment of a localized pleurodesis chemical delivery system.
Detailed Descr~tion 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
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.
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 the walls of the
thoracic
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
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CA 02469523 2004-06-03
lobes or sections of lungs varies from mammal to mammal. Healthy lungs, as
discussed below, have a tremendous surface area for gas/air exchange. Both
the left and right lung is covered with a pleural membrane. Essentially, the
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
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
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
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 air/gas 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
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CA 02469523 2004-06-03
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
bronchioles; however, acute bronchitis is generally associated with a viral
and/or bacterial infection and its duration is typically much shorter than
chronic
bronchitis. In chronic bronchitis, the bronchial tubes secrete too much mucus
as part of the body's defensive mechanisms to inhaled foreign substances.
Mucus membranes comprising ciliated cells (hair like structures) tine 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
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CA 02469523 2004-06-03
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 waNs 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
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 airways. Consequently, 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
they 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.
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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
S 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 cannula 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.
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), known 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
CA 02469523 2004-06-03
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, and/or standard X-ray imaging.
Once the diseased tissue is located, pressurized oxygen may be directly
delivered to these diseased areas and more 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 102 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
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 1 /16
inch to about 1 /2 inch and more preferably from about 1 /8 inch to about
1/4 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 108 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
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CA 02469523 2004-06-03
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 airtight 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 wall 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
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 performed 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 canying conduit 104
may be sealed to the skin of the thoracic wall utilizing an adhesive. As
illustrated, the oxygen carrying conduit 104 comprises a flange 200 having a
biocompatible adhesive coating on the skin contacting surface. 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
17
CA 02469523 2004-06-03
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 embodiment 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. In 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
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 fluid 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 wall 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
18
CA 02469523 2004-06-03
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
bypass/direct 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 portion 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
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 of radial support of
the
19
CA 02469523 2004-06-03
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
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 filter/one-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
conduit
704 is illustrated, multiple conduits may be utilized in each lung 708 if it
is
determined that there is 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
CA 02469523 2004-06-03
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 may be 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 filfer/one-way valve 706
serves a number of functions. The fiiter/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
lungs 708 to the trap 702 is maintained in this one direction: The filter
portion
of the filter/one-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 lung 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 1116 inch
to about 1/2 inch, and more preferably from about 1/8 inch to about 1/4 inch.
The filter/one-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
21
CA 02469523 2004-06-03
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
filter/one-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.
1f 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, if
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
into the conduit 704 will give the conduit collapse resistance and collapse
recovery properties.
Expandable features at the end of the conduit 704 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 adhesive/sealant to join as described in
detail subsequently.
In order for the exemplary collateral ventilation bypass trap system 700
to function, an airtight seal is preferably maintained where the air carrying
conduit 704 passes through the thoracic cavity and lungs 708. 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. One
22
CA 02469523 2004-06-03
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 pleurectomy 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
FocaUSeal-L which is indicated for use on a lung for sealing purposes.
FocaUSeal-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.
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, atemotomy 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 then be made after the joint has been adequately created
between the conduit component and the lung pleural surface. 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.
23
CA 02469523 2004-06-03
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.
Figure 8 illustrates another exemplary collateral ventilation bypass
system 800. In this exemplary embodiment, the trachea is utilized to remove
trapped air rather than the native airways. As illustrated, a first conduit
802
extends from the patient's trachea 804, or other proximal airways, including
the
bronchus, to a position external of the patient's body. A second conduit 806
is
connected to the first conduit 802 via a fitting 808 and passes through the
thoracic wall 810 and passes through the lung 812 at the site determined to
have the highest degree of collateral ventilation. If more than one site is
determined to have a high degree of collateral ventilation, multiple conduits
may be utilized. In operation, when the patient exhales, the pressure in the
lungs is greater than the pressure in the trachea 804; accordingly, the air in
the
highly collaterilized areas of the lung will travel through the first and
second
conduits 802, 806 to the trachea 804 and out of the patient's nose and mouth
with the normally exhaled air.
The first and second conduits 802, 806 may comprise any suitable
biocompatible tubing having a resistance to the various gases and other
constituents contained in inhaled and exhaled air. As in previously described
embodiments, the first and second conduits 802, 806 comprise tubing having
an inside diameter in the range from about 1/16 inch to about 1/2 inch, and
more preferably from about 1/8 inch to about 1/4 inch.
24
CA 02469523 2004-06-03
The connection of the first conduit 802 to the trachea 804 may comprise
any suitable airtight seat. For example, a fluid communication between the
trachea 804 and the first conduit 802 may be established in a manner identical
to that established for a tracheotomy. In addition, as stated above, in order
for
the collateral ventilation bypass system 800 to function, an airtight seal is
preferably maintained where the second conduit 806 passes through the
thoracic wall 810 and into the lungs 812. An exemplary method for creating
this airtight seal comprises forming adhesions between the visceral pleura of
the lung and the parietal pleura. This may be achieved using either chemical
methods, including irritants, surgical methods, including pleurectomy or
thorascopic talc pleurodesis, or radiotherapy methods, including radioactive
gold or external radiation.
The creation of the opening in the thoracic wall may be accomplished in
a number of ways. For example, the procedure may be accomplished using an
open chest procedure, atemotomy 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 then be made after the joint has been adequately created
between the conduit component and the lung pleural surface. 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 conduits 802, 806 may be sealed to the skin at the sites by any
known methods, including those described above with respect to Figures 2
through 5. The connection of the extrathoracic component, conduit 806, may
comprise a drug, chemical, agent, or other means for preventing or
substantially reducing the risk of infection.
CA 02469523 2004-06-03
The fitting 808 connecting the first and second conduits 802, 806 may
comprise any suitable device for creating an airtight seal. The fitting 808
may
comprise any type of threaded or non-threaded union, compression fittings
similar to compressor type fittings or any other suitable device for
establishing
an airtight seal and providing for puick release between the two ends of the
fitting 808. This type of design would allow easy access for periodic
maintenance of the system 800, for example, cleaning the conduits 802, 806.
Since the fitting 808 is external to the body, access to the inner body
component of the system 800 would be easier. Essentially, access of the
system 800 from outside the body would allow for maintenance and
diagnosis/observation of the system 800 without subjecting the patient to
additional stress and risk. 1t would also be less time consuming for the
doctor.
Figure 9 illustrates an alternate exemplary embodiment of the exemplary
collateral ventilation bypass system 800 described above. In this exemplary
embodiment, the system 900 comprises an externally positioned access port
908. As illustrated, a conduit 902 extends from the patient's trachea 904, or
other proximal airways, including the bronchus, through a suitable passageway
internal to the patient's body and then passes through the lung 912 at the
site
determined to have the highest degree of collateral ventilation. As set forth
above, if more than one site is determined to have a high degree of collateral
ventilation, multiple conduits may be utilized. At the desired location within
the
body, the access port 908 may be placed in-line with the conduit 902 such that
at least a portion of the access port 908 is accessible outside of the body.
Essentially, the access port 908 should allow the patient or a doctor to open
the port and access the system 900 within the patient's body for maintenance
and diagnosis/observation of the system 900 as described above.
The access port 908 may comprise any.suitable device for providing an
airtight seal when closed and easy access to the conduit 902 when open. The
access port 908 may comprise various valve arrangements and connectors for
connecting other components which may be utilized for various functions. For
example, oxygen may be supplied directly to the patient's lungs 912 if needed.
26
CA 02469523 2004-06-03
In this instance, a valve may be needed to prevent the oxygen from bypassing
the lungs 912 and go straight to the trachea 904.
All the remaining components may be the same as described above. In
addition, all seals may be accomplished as described above.
In yet another alternate exemplary embodiment, the extrathoracic
access port 908, illustrated in Figure 9, may be positioned just under the
skin
so that it is accessible percutaneously. Essentially, the access port would
not
truly be extrathoracic, but rather just located under the skin and accessible
extrathoracically. In this exemplary embodiment access would not be as easily
accessible; however, the access point would remain more discrete than the
previously described exemplary embodiments. Figure 10 illustrates this
exemplary embodiment.
As illustrated in Figure 10; the collateral ventilation bypass system 1000
comprises a conduit 1002 that extends from the patient's trachea 1004, or
other proximal airways, including the bronchus; through a suitable passageway
internal to the patient's body and then passes through the lung 1012 at the
site
determined to have the highest degree of collateral ventilation. As set forth
above, if more than one site is determined to have a high degree of collateral
ventilation, multiple conduits may be utilized. At the desired location within
the
body, an internal access port 1008 may be placed in-line with the conduit
1002.
The access port 1008 may comprise any suitable device that allows access via
percutaneous means. All remaining components may be the same as
described above. In addition, all seals may be accomplished as described
above.
It is important to note that in each of the above-described exemplary
embodiments, additional components may be added that function to prevent
flow from the trachea end of the conduit to the lung. For example, one or more
valves may be incorporated throughout the systems to prevent mucus and
other substances from entering or re-entering the lung. The main function of
27
CA 02469523 2004-06-03
the system is to allow exhalation. In theory, patients with emphysema have
increased resistance to expiration and not inhalation. Any suitable valves may
be utilized, for example, one-way check valves.
As described above, pulmonary emphysema leads to the breakdown of
lung tissue, which in turn leads to the reduced ability of the lungs to recoil
and
the loss of radial support of the airways. Consequently, 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 or lungs 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.
Lung volume reduction surgery is an extremely traumatic procedure that
involves removing part or parts of the lung or lungs. By removing the portion
of
the lung or lungs which is hyperinflated, pulmonary function may improve due
to a number of mechanisms; including enhanced elastic recoil, correction of
ventilation/perfusion mismatch and improved efficiency of respiratory work.
Essentially, as the emphysematous tissue volume is reduced, the healthier
tissue is better ventilated. However, lung volume reduction surgery possesses
a number of potential risks as described in more detail subsequently.
The collateral ventilation bypass trap system 700, illustrated in Figure 7,
and the collateral ventilation bypass system 800, illustrated in Figure 8,
utilize
the collateral ventilation phenomenon to allow the air entrapped in the lung
or
lungs to bypass the native airways and be expelled either to a containment
vessel or to the ambient environment. However, in an alternate exemplary
embodiment, a device, which works similarly to collateral ventilation bypass
28
CA 02469523 2004-06-03
and provides results commensurate with lung volume reduction surgery, is
disclosed herein. Essentially, in this exemplary embodiment, the invention is
directed to a device and associated method for assisting pulmonary
decompression. fn other words, the present invention is directed to pulmonary
decompression assist device and method that would provide a means for the
removal of trapped air in the emphysematous lung and the maintenance of the
emphysematous area compressed to a smaller volume, with the result being
that healthier lung tissue will have more volume in the thoracic cavity to
ventilate. The effects of this device may be similar to that of lung volume
reduction surgery.
The exemplary pulmonary decompression assist device of the present
invention may be strategically positioned in the body of a patient such that
it is
in fluid communication with the patient's lung or lungs and the external
environment. The device would allow air to be exhaled out from the lung or
lungs through the native airways while assisting in removing trapped air in
the
hyperinflated portion of the lung or lungs. Lung volume reduction surgery is
an
extremely invasive and traumatic procedure that in a substantially high number
of cases causes the patients undergoing the procedure to become excluded
from being a candidate for lung transplantation. The device of the present
invention provides for a minimally invasive procedure for causing the lung
volume to reduce similarly to lung volume reduction surgery while allowing the
patient to remain a'viable candidate for lung transplantation.
The exemplary pulmonary decompression device may utilize any
number of known techniques for creating a sufficient pressure differential
between the inside of the lung or lungs and an area external of the lung or
lungs to allow the trapped air to exit the lung or lungs. The device may
comprise any suitable device such as pumps or fans or any other means to
create the pressure differential. If the collateral airflow and areas of
emphysema are situated so that air may reinfiate that area, the device may be
configured to continuously draw air from the lung or lungs to maintain a
smaller
lung volume of the emphysematous tissue. The device may be left in the
2s
CA 02469523 2004-06-03
patient's body indefinitely in order to maintain the compression of the
emphysematous tissue in the lung or lungs. In addition; in order to maintain
the cleanliness of the device and the safety of the patient, the device may be
constructed as a disposable device and be replaced at various intervals. In
addition, portions of the device that are easily accessible may be made
disposable. Alternately, the device may be constructed for easy removal, easy
cleaning and easy replacement.
Referring to Figure 11, there is illustrated an exemplary pulmonary
decompression device 1100 in accordance with the present invention. As
described herein, there is generally an optimal location to penetrate the
outer
pleura of the lung to access the most collaterally ventilated area or areas of
the
lung and a variety of techniques to locate the area or areas. Once the desired
location is determined, the decompression device 1100 may be inserted into
the lung 1102. On insertion and placement of the decompression device 1100
into the lung 1102, it is particularly advantageous to establish an airtight
seal of
the parietal and visceral pleurae. If a proper airtight seal is not created
between the decompression device, parietal and visceral pleurae, then a
pneumothorax may occur.
It is important to note that one or more devices may be utilized in each
lung to remove trapped air from highly coilateralized areas. Alternately, a
single device with multiple conduits may be utilized. As illustrated in Figure
11,
the decompression device 1100 is placed in the lung 1102 in the area of
highest collateral ventilation i 104. In one exemplary embodiment, only a
first
section 1106 of the decompression device 1100 is positioned within the lung
1102 while a second section 1108 of the decompression device 1100 is
secured external to the lung 1102. The sealing of the device 1100 may be
made in accordance with any of the devices and methodologies described
herein.
At least a portion of the second section 1108 is external to the patient's
body. The portion of the second section 1108 that is external to the patient's
so
CA 02469523 2004-06-03
body may exit the body at any suitable location. In one exemplary
embodiment, the portion of the second section 1108 exists the body through
the chest and thus may be sealed in accordance with any of the devices and
methodologies described herein.
The first section 1106 may comprise any suitable biocompatible material
configured to facilitate the flow of air from the lung 1102. For example, the
first
section 1106 may comprise a conduit similar in size, material and construction
as the other conduits described herein. The second section 1108 may be
connected to the first section 1106 by any suitable means, including threaded
unions or compression type fittings. The second section 1108 comprises a
housing for an apparatus that draws air from the hyperinflated portion of the
lung 1104 through the first section 1106 and directs it out of the patient's
body.
The apparatus may include any suitable device for creating a pressure
differential between the inside and outside of the lung 1 i 02 such that air
will
easily flow from the lung 1102. The apparatus may include a miniature pump
or fan. The miniature pump or fan may be powered by any suitable means;
including batteries or rechargeable batteries. In the above-described
exemplary embodiment, the miniature pump or fan and its power supply may
be housed completely in the housing. In other alternate exemplary
embodiments, one or more of the pumplfan or power supply may be located
remotely from the second section 1108. For example; the second section 1108
may simply comprise a second conduit removably connected on one end to the
first conduit and on a second end to the apparatus that draws air from the
diseased section of the lung 1104.
In the exemplary embodiment illustrated in Figure 11, the apparatus that
draws air from the diseased section of the lung 1104 and its associated power
supply are housed within the second section 1108. This design provides the
most freedom for the patient. Various known miniature vacuum pumps or fans
may be used to continuously draw air from the diseased section of the lung
1104, thereby reducing the emphysematous tissue volume and allowing the
healthier tissue to ventilate better. The miniature fanlpump and associated
31
CA 02469523 2004-06-03
power supply may be separate components or a single component. These
miniature devices may comprise microefectromechanical systems or MEMS, or
any other suitable device for drawing air from one location and venting it to
a
second location. The decompression device 1100 should be designed to be
easily maintained. For example, the second section 1108 may be made such
that it can be removed, the power supply recharged and the other components
cleaned and then replaced. Alternately, the second section 1108 may simply
be disposable.
The power supply may comprise any suitable means for supplying
power continuously for extended periods of time. The power supply may
comprise batteries, rechargeable batteries, piezoelectric devices that
generate
electrical power from mechanical strain or any other suitable device. In
addition, other than a fan or pump for creating a vacuum, some type of
switching elements may be utilized for creating a slight pressure
differential.
Accordingly, rather than a resection of the lung tissue, the
decompression device removes trapped air from the emphysematous section
of the lung and maintains the emphysematous section in a compressed state
or smaller volume, thereby allowing the healthier lung tissue more volume in
the thoracic cavity to ventilate. Figure 12a illustrates the decompression
device
1100 removing air from the hyperinflated portion 1202 of the lung 1200. As
illustrated, in this lung, the hyperinflated or emphysematous portion 1202 of
the
lung 1200 is larger than the healthy section or portion 1204 of the lung 1200.
As the device 1100 continues to remove the accumulated or trapped air, the
volume of the hyperinflated portion 1202 of the lung 1200 shrinks, thereby
allowing the healthier portion 1204 more room to fully ventilate, thereby
increasing in volume as illustrated in Figure 12b.
In an alternate exemplary embodiment, a more passive device may be
utilized for reducing the size of the lung. A lung reduction device may be
strategically positioned about the body of a patient and access the patient's
lung or lungs. The device would allow air to be expelled from the lung or
lungs
32
CA 02469523 2004-06-03
while preventing air from re-entering therethrough. Essentially, the device
would comprise at least one component that accesses the outer pleural layer
of the emphysematous portion or portions of the patient's lung or lungs. This
at least one component will utilize the collateral ventilation of the lung or
lungs
and allow the entrapped air in the emphysematous portion or porkions of the
lung or lungs to bypass the native airways and expel through to the outside of
the body through a second component. The second component includes a
feature that allows air to flow from the lung or lungs to the ambient
environment, but not from the ambient environment back into the lung or lungs.
If the collateral airflow and areas of emphysema are situated so that air
cannot
reinflate these portions of the lung or lungs, then a size reduction of that
area
of the lung should occur
Referring to Figures 13a and 13b, there is illustrated an exemplary lung
reduction device 1300 in accordance with the present invention. As described
herein, there is generally an optimal location to penetrate the outer pleura
of
the lung to access the most collaterally ventilated area or areas of the lung
or
lungs and a variety of techniques to locate these areas. Once the desired
location or locations are determined, the lung reduction device 1300 may be
inserted into the lung 1302. The insertion or introduction of the device 1300
may be accomplished utilizing a number of minimally invasive techniques, for
example, percutaneously or endoscopically, thereby substantially reducing the
risk to the patient and trauma to the lung or lungs. It is important to note
that
all of the systems and devices described herein are preferably implanted
utilizing minimally invasive techniques. On insertion and placement of the
lung
reduction device 1300 into the lung 1302, it is particularly advantageous to
establish an airtight seal of the parietal and visceral pleurae utilizing any
of the
techniques, devices and processes described herein. If an airtight seal is not
established between the lung reduction device 1300, parietal and visceral
pleurae, then a pneumothorax may occur.
It is important to note that one or more lung reduction devices may be
utilized in each lung to remove trapped air from highly colfateralized areas.
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CA 02469523 2004-06-03
Alternately, a single lung reduction device in fluid communication, through
conduits or other similar means, with multiple locations may be utilized. For
case of explanation, a single device and single diseased portion is described
and illustrated. Once again, referring to Figures 13a and 13b, the lung
reduction device 1300 is implanted in the lung 1302 in the area of highest
collateral ventilation 1304. In the exemplary embodiment illustrated, a first
section 1306 of the lung reduction device 1300 is positioned within the inner
volume of the lung 1302 while a second section 1308 of the lung reduction
device 1300 is secured to the patient's body external to the lung 1302. The
first section 1306 of the device 1300 accesses the parenchyma of the lung
1302. The parenchyma are the cells in tissues that are concerned with
function rather than structure. In other words, the first section 1306
accesses
the alveoli of the lung 1302. The attainment of an airtight seal of the lung
reduction device 1300 may be made in accordance with any of the devices and
methodologies described herein.
At least a portion of the second section 1308 is external to the patient's
body. The portion of the second section 1308 that is external to the patient's
body may exit or extend from the body at any suitable location. Preferably,
the
portion of the second section 1308 exits at a location that proves to be of
minimum burden to the patient and allows for easy access for maintenance,
repair or replacement. In one exemplary embodiment, the portion of the
second section 1308 exits the body through the chest and thus may be sealed
in accordance with any of the devices and methodologies described herein.
The first section 1306 may comprise any suitable device for facilitating
the flow of air from the lung 1302. For example, the first section 1306 may
comprise a conduit similar in size, material and construction or any of the
other
conduits described herein. The second section 1308 may be connected to the
first section 1306 by any suitable means, including threaded connectors,
unions or compression type fittings.
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CA 02469523 2004-06-03
The second section 1308 may comprise any suitable means for allowing
one-way airflow. In one exemplary embodiment, the second section 1308
comprises a housing 1310 and a one-way valve 1312. The housing 1310 may
be formed from any suitable biocompatible material. A portion of the housing
1310 houses the one-way valve 1312 while another portion of the housing
1310 forms the portion that is external to the body. The one-way valves 3i 2
may comprise any suitable pressure actuated valve, which allows air to flow
from one lung 1302 to the ambient environment. The one-way valve 1312 may
comprise a check valve, a reed valve, needle valves, flapper check valves or
any other suitable device. In preferred embodiments, the one-way valve 1312
requires only a slight pressure differential to open and allow air flow from
the
lung 1302 to the ambient or external environment, but does not allow air flow
back into the lung 1302 even under substantial reverse pressure.
In operation, when the person inhales, the volume of the thoracic cavity
increases by the contraction of the diaphragm and thus the volume of the lungs
also increases. 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
and
thus air flows through the respiratory passageways into the lungs until the
pressure equalizes. When the person exhales, 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.
However, in the diseased area 1304 of the lung 1302, normal exhalation does
not work for the reasons described herein and thus the increased pressure in
the lung 1302 opens the one-way valve 1312 and air flows from the diseased
portion 1304 through the first section 1306, through the one-way valve 1312
and out of the body.
The lung reduction device 1300 may be left in the lung indefinitely to
maintain the compression of the emphysematous tissue lung 1300 as
CA 02469523 2004-06-03
described above with respect to the decompression device. In order to
maintain cleanliness and safety, the lung reduction device 1300 or at least
portions thereof may be made disposable and thus be replaced at regular
intervals or when needed. As the lung reduction device 1300 continues to
allow the trapped air to exit the lung 1302, the volume of the hyperinflated
or
diseased portion 1304 of the lung 1300 shrinks, thereby allowing the healthier
portion of the lung 1300 more room to fully ventilate, thereby increasing in
volume as illustrated in Figure i 3b.
The lung reduction device 1300 may be left in the body until the area of
the compressed emphysematous tissue has permanently compressed,
atelectasis. At this point, the lung reduction device 1300 may potentially be
removed safely. If healing of the insertion site of the reduction device 1300
has occurred, the fistula created may be permanently sealed.
In the above-described exemplary apparatus and procedure for
increasing expiratory flow from a diseased lung using the phenomenon of
collateral ventilation, there will be an optimal location to penetrate the
outer
pleura of the lung to access the most collaterally ventilated area or areas of
the
lung. In addition, in the above-described exemplary pulmonary decompression
assist device, there is an optimal location for decompressing the
hyperinflated
lung or lungs. 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 airtight seal of the parietal (thoracic wall) and
visceral (lung) pleurae. If a proper airtight seal is not created between the
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 airtight seal should preferably be maintained.
One way to achieve an airtight seal is through pleurodesis, i.e. an
obliteration of the pleural space. There are a number of pleurodesis methods,
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CA 02469523 2004-06-03
including chemical, surgical and radiological. In chemical pleurodesis, an
agent such as tetracycline, doxycycline, bleomycin or nitrogen mustard may be
utilized. In surgical pfeurodesis, 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 airtight seal of the above-
described
apparatus is described below. The chemical(s), agents) and/or compounds)
are used to create a pleurodesis between the parietal and visceral pleura so
that a component of the apparatus may penetrate through 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 chemical(s), agents) andlor 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 creating a localized
pleurodesis. Referring to Figure 14, 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.
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 14, the catheter 1400 is inserted into the patient
such that the distal end 1402 is positioned in the pleural space 1404 between
the thoracic wall 1408 and the lung 1406. In the illustrated exemplary
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CA 02469523 2004-06-03
embodiment, the distal end 1402 of the catheter 1400 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 i 410. The distal end 1402 of the
catheter 1400 comprising a plurality of holes or openings 1412 through which
the chemical(s), agents) and/or compounds) are released. As stated above,
the distal end 1402 may comprise any suitable size, shape or configuration.
Once the chemical(s), agents) and/or compounds) are delivered, the catheter
1400 may be removed to allow for implantation of the conduit 704 (Figure 7).
Alternately, the catheter 1400 may be utilized to facilitate delivery of the
conduit
704.
The distal end or tip 1402 of the catheter 1400 should preferably
maintain its desired size, shape and/or configuration once deployed in the
pleural space. This may be accomplished in a number of ways. For example,
the material forming the distal end 1402 of the catheter 1400 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 1402 of the
catheter 1400. 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
1400 may be viewed under x-ray fluoroscopy and aid in determining when the
catheter 1400 is at the location of the highest collateral ventilation.
In another alternate exemplary embodiment, a local drug delivery device
may be utilized to deliver the pleurodesis chemical(s), agents) and/or
compound(s). 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 pleurodesis. In this exemplary embodiment, chemical(s), agents)
38
CA 02469523 2004-06-03
and/or compounds) may be affixed to an implantable medical device. The
medical 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) and/or compounds) may be coated on the
device utilizing any number of well known techniques including, spin 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 the medical device, they may be coated onto the surface 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 biodegradable material
which elutes the chemical(s), agents) and/or compounds) as the device
degrades.
The implantable medical device may comprise any suitable size, shape
and/or configuration, and may be formed using any suitable biocompatible
material. Figure 15 illustrates one exemplary embodiment of an implantable
medical device 1500. In this embodiment, the implantable medical device
1500 comprises a substantially cylindrical disk 1500. The disk 1500 is
positioned in the pleural space 1502 between the thoracic wall 1504 and the
lung 1506. Once in position, the disk 1500 elutes or otherwise releases the
chemical(s), agents) and/or 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 1500 may be formed from a biodegradable material that elutes
39
CA 02469523 2004-06-03
the chemical(s), agents) and/or compounds) as the disk 1500 itself
disintegrates or dissolves. Depending upon the material utilized in the
construction of the disk 1500, a non-biodegradable disk 1200 may or may not
require removal from the pleural cavity 1502 once the pleurodesis is formed:
For example, it may be desirable that the disk 1500 is a permanent implant
that
becomes integral with the pleurodesis.
As described in the previous exemplary embodiment, the disk 1'500 may
comprise a radiopaque marker or be formed from a radiopaque material. The
radiopaque marker or material allows the disk i 500 to be seen under
fluoroscopy and then positioned accurately.
In yet another alternate exemplary embodiment, the fluid characteristics
of the chemical(s), agents) ancUor compounds) may be altered. For example,
IS the chemical(s), agents) and/or compounds) may be made more viscous.
With a more viscous chemical agent and/or compound, there would be less
chance of the chemical, agent and/or compound moving from the desired
location in the pleural space. The chemical(s), agents) and/or 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) and/or compounds) with regard to the optimal
location of collateral ventilation.
The chemicals}, agent(s) and/or 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.
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
ao
CA 02469523 2004-06-03
constructions described and illustrated, but should be constructed to cohere
with all modifications that may fall within the scope of the appended claims.
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