U.S. patent application number 13/279281 was filed with the patent office on 2012-02-16 for methods, systems and devices for desufflating a lung area.
This patent application is currently assigned to Anthony David Wondka. Invention is credited to Anthony David Wondka.
Application Number | 20120041361 13/279281 |
Document ID | / |
Family ID | 34107509 |
Filed Date | 2012-02-16 |
United States Patent
Application |
20120041361 |
Kind Code |
A1 |
Wondka; Anthony David |
February 16, 2012 |
Methods, Systems and Devices for Desufflating a Lung Area
Abstract
Methods, systems and devices are described for temporarily or
permanently evacuating stagnating air from a diseased lung area,
typically for the purpose of treating COPD. Evacuation is
accomplished by displacing the stagnant CO.sub.2-rich air with a
readily diffusible gas using a trans-luminal indwelling catheter
specially configured to remain anchored in the targeted area for
long term treatment without supervision. Elevated positive gas
pressure in the targeted area is then regulated via the catheter
and a control unit to force under positive pressure effusion of the
diffusible gas out of the area into neighboring areas while
inhibiting infusion of other gases thus effecting a gradual gas
volume decrease and deflation of the targeted area, thereby
reducing volume of ineffective areas, increasing tidal volume of
better areas, and improving lung mechanics.
Inventors: |
Wondka; Anthony David;
(Thousand Oaks, CA) |
Assignee: |
Wondka; Anthony David
Thousand Oaks
CA
|
Family ID: |
34107509 |
Appl. No.: |
13/279281 |
Filed: |
October 23, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10831573 |
Apr 24, 2004 |
8082921 |
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13279281 |
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60465028 |
Apr 25, 2003 |
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Current U.S.
Class: |
604/24 ;
604/23 |
Current CPC
Class: |
A61M 16/04 20130101;
A61M 2016/0027 20130101; A61M 16/0486 20140204; A61M 16/0463
20130101; A61M 2230/432 20130101; A61M 16/00 20130101; A61M 16/0434
20130101 |
Class at
Publication: |
604/24 ;
604/23 |
International
Class: |
A61M 37/00 20060101
A61M037/00; A61M 25/00 20060101 A61M025/00 |
Claims
1. An apparatus for improving lung mechanics, the apparatus
comprising a DLMW gas delivery system comprising: a. a supply of
DLMW gas; b. a catheter delivery system connected at one end to the
supply of DLMW gas and connected to the patients lung airway at the
other end; c. a control system to control the delivery of the DLMW
gas from the supply to the lung through the catheter such that
diseased areas of the lung exhibiting poor ventilation are reduced
in volume so that the lung mechanics can improve; and wherein
improved lung mechanics is selected from the group of decreased
dynamic hyperinflation, decreased static hyperinflation, diaphragm
position, accessory muscles, reduced residual volume, increased
tidal volume.
2. An apparatus for increase the tidal volume of a lung area by
reducing the residual volume of a neighboring target diseased lung
area using Diffusible Low Molecular Weight (DLMW) gas, the
apparatus comprising: a. a supply of diffusible low molecular
weight (DLMW) gas comprising a diffusivity of at least 10.sup.4
cm2/sec, and a molecular weight of 2-20 atomic mass units; b. a
catheter with one end adapted to be connected to the supply of DLMW
gas and the opposite end adapted to be placed in an airway leading
to said target lung area, wherein the catheter comprises an airway
anchor adapted to secure the catheter in a position in the airway
for extended periods without occluding the airway and without
requiring continuous supervision from a person; c. a control unit
in connection to the supply of DLMW gas, comprising a gas delivery
control system adapted to provide controlled delivery of the DLMW
gas into the target lung area, said controlled delivery comprising
reducing the volume of the lung area.
3. An apparatus for reducing the residual volume of a target lung
area using Diffusible Low Molecular Weight (DLMW) gas, the
apparatus comprising: a. a supply of diffusible low molecular
weight (DLMW) gas; b. a catheter with one end adapted to be
connected to the supply of DLMW gas and the opposite distal end
adapted to be placed in an airway leading to said target lung area;
c. a control unit in connection to the supply of DLMW gas,
comprising a gas delivery control system adapted to provide
controlled delivery of the DLMW gas into the target lung area, said
controlled delivery comprising reducing the volume of the lung
area.
4. An apparatus as in claim 3 wherein the catheter further
comprises a non occlusive anchor at the distal end, wherein the
anchor secures the catheter distal end in position for an extended
period of more than 30 minutes without occluding the airway and
without requiring supervision from a person.
5. An apparatus as in claim 3 wherein the gas delivery control
system is adapted to control the pressure of DLMW gas in the lung
area to a desired pressure level.
6. An apparatus as in claim 3 wherein the DLMW gas comprises a
molecular weight of 2-20 atomic mass units and a diffusivity of at
least 10.sup.4 cm2/sec.
7. An apparatus as in claim 3 wherein the catheter comprises a
lumen for gas delivery and a lumen for gas removal.
8. An apparatus as in claim 3 wherein the gas delivery control
system is adapted to control the increase in volume in a
neighboring lung area.
9. An apparatus as in claim 3 wherein the gas delivery control
system is adapted to improve lung mechanics by one or more of the
following: improve gas exchange in a neighboring lung area; improve
ventilation in a neighboring lung area; increase volume in a
neighboring lung area; improve lung muscle resting position.
10. An apparatus as in claim 3 wherein the catheter is adapted with
a lumen to exhaust gas out of the target lung area.
11. An apparatus as in claim 3 wherein the distal end of said
catheter comprises both a non-occlusive anchor for anchoring in
said bronchus, and a radially inflatable occlusive member which
comprises a means to intermittently inflate to occlude the annular
space around said catheter in the said area's feeding bronchus, and
optionally wherein said catheter and said pneumatic control unit
automatically work in unison such that said inflation and occlusion
is synchronized with said DLMW gas delivery.
12. A catheter as in claim 56 wherein said anchoring member
occludes said bronchus intermittently wherein said pneumatic
control unit comprises a means to synchronized delivery of said
DLMW gas with said occlusion of said bronchus.
13. An apparatus as in claim 3 wherein said control unit comprises
a control algorithm for producing one or more of the following gas
delivery profiles: constant, intermittent, oscillatory, synchronize
said DLMW gas delivery and optionally said gas exhaust with the
patient's breathing pattern for the purpose of maintaining a
desired pressure in said targeted lung area.
14. An apparatus as in claim 3 wherein the control unit controls
gas delivery by one or more of the following: said targeted lung
area pressure is measured through a lumen in the catheter in
communication with a pressure sensing means; multiple pressure
sensing ports integral to the catheter to measure flow into and out
of the catheter; a gas concentration measuring means.
15. An apparatus as in claim 3 wherein said control unit is
integrated with a mechanical ventilator
16. An apparatus as in claim 3 wherein said pneumatic control unit
is adapted for ambulatory use portable and wearable by the user,
for example with a belt clip, fanny pack or shoulder strap and
optionally includes a replaceable or refillable DLMW gas
cartridge.
17. A catheter as in claim 3 further comprising one or more of the
following: wherein said catheter shaft comprises a de-coupling
means, said means permitting a disconnection of the proximal end of
said catheter from balance of said catheter; wherein said catheter
shaft comprises a concentric connection means, said means further
comprising an anchoring feature at the point of entry to the body
and optionally providing a sealing feature at the point of entry to
the body.
18. An apparatus as described in claim 3 further comprising a means
to delivery a therapeutic agent selected from the group of: a
mucolytic, an agent to increase or decrease tissue diffusivity,
bronchodilators, surface tension modifiers,
19. An apparatus as in claim 3 further comprising one or more of
the following: the catheter anchor comprises a radially
compressible structure with a resting diameter concentric to said
catheter shaft typically 2-20 mm in diameter, such as but not
limited a wire structure attached to the shaft of said catheter,
such as but not limited to a wire framed cylindrical or spherical
structure, such as but not limited to straight non-crossing wires,
woven wires and braided wires; the catheter comprises an outer
concentric sleeve wherein said sleeve is axially slide-able with
respect to said catheter shaft and further wherein said anchoring
member is compressed into a radially collapsed state between said
catheter shaft and said sleeve and further wherein upon moving said
catheter or said sleeve axially, said anchoring member is released
and freely radially expands towards its resting diameter, said
expansion producing tension against said bronchial wall, said
tension typically 0.5-3.0 lbs force and preferably 0.75-1.5 lbs
force; the catheter comprises an inflatable anchoring member and
comprises an inflation or deflation means for elective inflation;
the catheter comprises an outer catheter and an inner catheter
wherein said inner catheter includes said non-occlusive anchor at
its distal end wherein said inner catheter and anchor protrudes
from the distal tip of said outer catheter; the catheter comprises
an outer diameter of typically 0.5-4.0 millimeters, most preferably
2-3 millimeters and a gas delivery lumen of typically 0.25-2
millimeters, most preferably 0.5 millimeters, and optionally
comprising a gas exhaust lumen of a diameter of typically 0.25-3
millimeters, most preferably 2 millimeters, and further comprising
a length of typically 80-200 centimeters, most preferably 100-140
centimeter.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the field of respiratory
therapy and specifically to the field of treating Chronic
Obstructive Pulmonary Disease (COPD).
[0002] COPD is a worldwide problem of high prevalence, effecting
tens of millions of people and is one of the top five leading
causes of death. COPD is a spectrum of problems, including
bronchitis and emphysema, and involves airway obstruction, tissue
elasticity loss and trapping of stagnant CO.sub.2-rich air in the
lung. There are two basic origins of emphysema; a lesser common
origin stemming from a genetic deficiency of
alpha.sub.1-antitripsin and a more common origin caused by toxins
from smoking or other environment sources. In both forms there is a
breakdown in the elasticity in the functional units, or lobules, of
the lung changing clusters of individual alveoli into large air
pockets, thereby significantly reducing the surface area for gas
transfer. In some cases air leaks out of the frail lobules to the
periphery of the lung causing the lung's membranous lining to
separate from the parenchymal tissue to form large air vesicles
called bullae. The elasticity loss also causes small airways to
become flaccid tending to collapse during exhalation, trapping
large volumes of air in the now enlarged air pockets, thus reducing
bulk air flow exchange and causing CO.sub.2 retention in the
trapped air. Mechanically, because of the large amount of trapped
air in the lung at the end of exhalation, known as elevated
residual volume, the intercostal and diaphragmatic inspiratory
muscles are forced into a pre-loaded condition, reducing their
leverage at the onset of an inspiratory effort thus increasing
work-of-breathing and causing dyspnea. In emphysema therefore more
effort is expended to inspire less air and the air that is inspired
contributes less to gas exchange.
[0003] Conventionally prescribed therapies for emphysema and other
forms of COPD include pharmacological agents such as aerosolized
bronchodilators and anti-inflammatories; long term oxygen therapy
(LTOT); respiratory muscle rehabilitation; pulmonary hygiene such
as lavage or percussion therapy; continuous positive airway
pressure (CPAP) via nasal mask; trans-tracheal oxygen therapy
(TTOT) via tracheotomy. These therapies all have certain
disadvantages and limitations with regard to effectiveness because
they do not address, treat or improve the debilitating elevated
residual volume in the lung. After progressive decline in lung
function despite attempts at conventional therapy, patients may
require mechanical ventilation.
[0004] Newer mechanical ventilation techniques to address COPD is
well reported in the literature and include HeliOx ventilation,
Nitric Oxide ventilation, liquid ventilation, high frequency jet
ventilation, and tracheal gas insufflation. Because these modes do
nothing to address, treat or improve the hyperinflated residual
volume of the COPD or emphysema patient, and because mechanical
ventilation is performed on the lung as a whole and inherently can
not target a specific lung area that might be more in need of
treatment, mechanical ventilation is an ineffective solutions.
[0005] There have been significant efforts to discover new
treatments such as treatment with substances that protect the
elastic fibers of the lung tissue. This approach may slow the
progression of the disease by blocking continued elastin
destruction, but a successful treatment is many years away, if
ever. It may be possible to treat or even prevent emphysema using
biotechnology approaches such as monoclonal antibodies, stem cell
therapy, viral therapy, cloning, or xenographs however, these
approaches are in very early stages of research, and will take many
years before their viability is even known.
[0006] In order to satisfy the more immediate need for a better
therapy a surgical approach called lung volume reduction surgery
(LVRS) has been extensively studied and proposed by many as a
standard of therapy. This surgery involves surgically resecting
some of the diseased hyperinflated lung tissue, usually the lung's
apical sections, thus reducing residual volume and improving the
patient's breathing mechanics and possibly gas exchange.
Approximately 9000 people have undergone LVRS, however the results
are not always favorable. There is a high complication rate of
about 20%, patients don't always feel a benefit possibly due to the
indiscriminate selection of tissue being resected, there is a high
degree of surgical trauma, and it is difficult to predict which
patients will feel a benefit. Therefore LVRS is not a practical
solution and inarguably some other approach is needed. The
attention on LVRS has created some new ideas on non-surgical
approaches to lung volume reduction. These approaches are presently
in experimental phases and are reviewed below.
[0007] New minimally invasive lung volume reduction methods
described in the prior art includes U.S. patents and patent
applications U.S. Pat. Nos. 5,972,026; 6,083,255; 6,174,323;
6,488,673; 6,514,290; 6,287,290; 6,527,761; 6,258,100; 6,293,951;
6,328,689; 6,402,754; US20020042564; US20020042565; US20020111620;
US20010051799; US20020165618; and foreign patents and patent
applications: EP1078601; WO98/44854; WO99/01076; WO99/32040;
WO99/34741; WO99/64109; WO0051510; WO00/62699; WO01/03642;
WO01/10314; WO01/13839; WO01/13908 WO01/66190.
[0008] U.S. Pat. No. 6,328,689 describes a method wherein lung
tissue is sucked and compressed into a compliant sleeve placed into
the pleural cavity through an opening in the chest. While this
method may be less traumatic than LVRS it presents new problems.
First, it will be difficult to isolate a bronchopulmonary segment
for suction into the sleeve. In a diseased lung the normally
occurring fissures that separate lung segments are barely present.
Therefore, in order to suck tissue into the sleeve as proposed in
the referenced invention, the shear forces on the tissue will cause
tearing, air leaks and hemorrhage. Secondly the compliant sleeve
will not be able to conform well enough to the contours of the
chest wall therefore abrading the pleural lining as the lung moves
during the breathing, thus leading to other complications such as
adhesions and pleural infections.
[0009] U.S. Patent applications 2002/0147462 and 2001/0051799
explain methods wherein adherent substances are introduced to seal
the bronchial lumen leading to a diseased area. It is proposed in
these inventions that the trapped gas will dissipate with time. The
main flaw with this method is that trapped gas will not effectively
dissipate, even given weeks or months. Rather, a substantial amount
of trapped gas will remain in the blocked area and the area will be
at heightened infection risk due to mucus build up and migration of
aerobic bacteria. Gas will not dissipate because: (1) blood
perfusion is severely compromised, exacerbated by the Euler reflex,
hence reducing gas exchange; (2) the tissue has low diffusivity for
CO.sub.2; and (3) additional gas will enter the blocked area
through intersegmental collateral flow channels from neighboring
areas. Another disadvantage with this invention is adhesive
delivery difficulty; controlling adhesive flow along with
gravitational effects makes delivery awkward and inaccurate.
Further, if the adhesive is too hard it will be a tissue irritant
and if the adhesive is too soft it will likely lack durability and
adhesion strength. Some inventors are trying to overcome these
challenges by incorporating biological response modifiers to
promote tissue in-growth into the plug, however due to biological
variability these systems will be unpredictable and will not
reliably achieve the relatively high adhesion strength required. A
further disadvantage with an adhesive bronchial plug, assuming
adequate adhesion, is removal difficulty, which is extremely
important in the event of post obstructive pneumonia unresponsive
to antibiotic therapy, which is likely to occur as previously
described.
[0010] U.S. Pat. No. 5,972,026 describes a method wherein the
tissue in a diseased lung area is shrunk by heating the collagen in
the tissue. The heated collagen fibers shrink in response to the
heat and then reconstitute in their shrunk state. However, a flaw
with this method is that the collagen will have a tendency to
gradually return towards its initial state rendering the technique
ineffective.
[0011] U.S. Pat. Nos. 6,174,323 and 6,514,290 describe methods
wherein the lung tissue is endobronchially retracted by placing
anchors connected by a cord at distal and proximal locations then
shortening the distance between the anchors, thus compressing the
tissue and reducing the volume of the targeted area. While
technically sound, there are three fundamental physiological
problems with this method. First, the rapid mechanical retraction
and collapse of the lung tissue will cause excessive shear forces,
especially in cases with pleural adhesions, likely leading to
tearing, leaks and possibly hemorrhage. Secondly, distal air sacs
remain engorged with CO.sub.2 hence occupy valuable space without
contributing to gas exchange. Third, the method does not remove
trapped air in bullae. Also, the anchors described in the invention
are not easily removable and they will likely tear the diseased and
fragile tissue.
[0012] U.S. Patent Applications 2002/0042564, 2002/0042565 and
2002/0111620 describe methods where artificial channels are drilled
in the lung parenchyma so that trapped air can then communicate
more easily with the conducting airways and ultimately the upper
airways, and/or to make intersegmental collateral channels less
resistive to flow, so that CO.sub.2-rich air can be expelled better
during respiration. Its inventors propose that this method may be
effective in treating homogeneously diffuse emphysema by preventing
air trapping throughout the lung, however the method does not
appear to be feasible because of the vast number of artificial
channels that would need to be created to achieve effective
communication with the vast number lobules trapping gas.
[0013] U.S. Pat. No. 6,293,951 and foreign patent WO01/66190
describe placing a one-way valve in the feeding bronchus of the
diseased lung area. The proposed valves are intended to allow flow
in the exhaled direction but not in the inhaled direction, with the
intent that over many breath cycles, the trapped gas in the
targeted area will escape through the valve thus deflating the lung
compartment. This mechanism can be only partially effective due to
fundamental lung mechanics, anatomy and physiology. First, because
of the low tissue elasticity of the targeted diseased area, a
pressure equilibrium is reached soon after the bronchus is valved,
leaving a relatively high volume of gas in the area. Hence during
exhalation there is an inadequate pressure gradient to force gas
proximally through the valve. Secondly, small distal airways still
collapse during exhalation, thus still trapping air. Also, the area
will be replenished with gas from neighboring areas through
intersegmental channels, trapped residual CO.sub.2-rich gas will
not completely absorb or dissipate over time and post-obstructive
pneumonia problems will occur as previously described. Finally, a
significant complication with a bronchial one-way valve is
inevitable mucus build up on the proximal surface of the valve
rendering the valve mechanism faulty.
[0014] U.S. Pat. Nos. 6,287,290 and 6,527,761 describe methods for
deflating a diseased lung area by first isolating the area from the
rest of the lung, then aspirating trapped air by applying vacuum to
the bronchi in the area, and plugging the bronchus either before or
after deflation. These methods also describe the adjunctive
installation of Low Molecular Weight gas into the targeted area to
facilitate aspiration and absorption of un-aspirated volume. It is
appreciated in these inventions that the trapped air in the lung is
not easily removable, and that aspiration of the trapped air may
require sophisticated vacuum control. While apparently technically,
physiologically and clinically sound, these methods still have some
inherent and significant disadvantages. First, aspiration of
trapped air by negative pressure is extremely difficult and
sometimes impossible because mucus in the distal airways will
instantly plug the airways when vacuum is applied because of the
vacuum-induced constriction of the fragile airways. Also, it is
difficult to avoid collapse of the distal airways when they are
exposed to vacuum due to their diseased in-elastic state. Special
vacuum parameters may enhance aspiration effectiveness by
attempting to mitigate airway collapse, but the parameters will
likely be different for different lung areas, for different times
and for different patients because effective vacuum parameters will
depend on the condition of hundreds of minute airways communicating
with the trapped gas. These airways, although theoretically in
parallel with one another, empirically do not behave in unison as
one collective airway, but rather as many individual dynamic
systems. Therefore, aspiration of an effective volume of trapped
air using vacuum may be impractical to implement. Secondly, a
vacuum technique will not remove the excessively trapped air in
bullae. Third, the collapse-by-aspiration techniques described in
these patents explain a relatively rapid deflation of the targeted
area conducted while a clinician is attending to the instruments
introduced into the lung, for example generally less than thirty
minutes, which is the time a patient can tolerate the bronchoscopic
procedure. Collapse-by-aspiration in this short a time period will
often produce traumatic tissue shearing between the collapsing and
non-collapsing areas, leading to tearing, leaks and hemorrhage,
especially if there are adhesions and bullae present. Forth,
although installation of low molecular weight gas may facilitate
collapse by absorption, infusion of respiratory gases from
neighboring lung areas through intersegmental collateral channels
will refill the targeted lung area rending collapse incomplete.
Some additional disadvantages of this technique include
post-obstructive pneumonia, assuming incomplete air removal; the
technique requires constant attendance of clinician which is
impractical if a slow, gradual collapse of the lung area is
desired; and finally the technique will be limited to large lung
sections because suctioning requires a relatively large catheter
inner diameter in order to avoid mucus plugging of the
instruments.
[0015] To summarize, methods for minimally invasive lung volume
reduction are either ineffective in collapsing the hyperinflated
lung areas, or do not remove air in bullae, or collapse tissue too
rapidly causing shear-related injury, or cause post-obstructive
pneumonia.
[0016] The present invention disclosed herein takes into
consideration the problems and challenges not solved by the
aforementioned prior art methods in treating COPD and emphysema. In
summary, this invention accomplishes (1) effective collapse of the
targeted bronchopulmonary compartment including bullae by keeping
the airways of the targeted area open by applying positive pressure
to them and employing gas diffusion laws, (2) a gradual controlled
atraumatic collapse of the targeted bronchopulmonary compartment
thus avoiding the shearing issues associated with attempted rapid
collapse, (3) avoidance of re-inflation by gas inflow through
collateral channels using pressure gradients and gas diffusion
laws, and (4) avoidance of post obstructive pneumonia. These
methods and devices thereof are described below in more detail.
BRIEF SUMMARY OF THE INVENTION
[0017] The present invention provides a method for treating COPD or
emphysema by reducing the volume of a targeted lung area (TLA), or
bronchopulmonary compartment, using a desufflation.sup.1 technique.
In general bronchopulmonary compartment desufflation ("BCD" or
"desufflation") is performed by (a) catheterizing the TLA, then (b)
displacing the trapped CO.sub.2-rich gas in the TLA by insufflating
with a readily diffusible low molecular weight (DLMW) gas, then (c)
pressurizing the DLMW gas in the TLA to a pressure greater than
neighboring lung areas by delivering more DLMW gas into the
targeted TLA and regulating pressure and gas concentration
gradients favorable to diffusion out of the TLA while preventing
infusion of respiratory gases, thereby causing a volumetric
reduction of the TLA. In further embodiments the deflated TLA is
restrained from re-expansion by tethering the tissue, or clamping
the tissue, or blocking airflow into the tissue with an
endobronchial plug. .sup.1 Desufflation: (n; v--desufflate) A
volumetric reduction of a space caused by first displacing native
fluid in the space by insufflating with a readily diffusible fluid
which then effuses out of the space effecting reduction.
[0018] More specifically in a preferred embodiment of the present
invention the feeding bronchus of the targeted TLA is catheterized
with an indwelling catheter anchored in the bronchus such that it
can remain in place for extended periods without being attended by
a person. The catheter enters the bronchial tree from the upper
airway, either through an artificial airway, such as a tracheal
tube, or through a natural airway, such as the nasal passage, or
through a percutaneous incision, such as a cricothyrotomy, and is
advanced to the targeted TLA through the bronchial tree with
endoscopic or fluoroscopic guidance. For ventilation and hygiene
considerations, the catheter entry point into the body typically
includes a self-sealing and tensioning connector that prevents
fluid from escaping from around the catheter shaft, but which
permits axial catheter sliding to compensate for patient movement
or for elective catheter repositioning. The tensioning connector
also prevents inadvertent dislodging of the catheter's distal end
anchor from the bronchus. In accordance with this embodiment the
catheter includes at least one lumen through which a DLMW gas is
delivered into the targeted TLA to displace the native gas while
also providing a pathway for exhausting of mixed gases exiting the
TLA. The DLMW gas delivery is regulated to create a sustained
average positive pressure in the TLA and hence a pressure gradient
favorable to gas exhausting. The gas displacement procedure is
continued for a sufficient duration, between one hour and 14 days,
to gradually displace a substantial percentage of native gases,
including trapped gas in Bulla, thus resulting in a predominate
DLMW gas composition.
[0019] In a further embodiment of the present invention, a vacuum
is applied to a lumen in the catheter to facilitate exhaust of
mixed gases and displacement of native gas however without creating
negative pressure in the TLA, which would collapse the airways, and
without disrupting the sustained periods of positive pressure in
the TLA which are absolutely critical to prevent airway collapse so
that proper gas mixing and displacement can occur. Optionally a
vacuum can be applied to bronchi of neighboring lung areas to
assist gas wash out and effusion from the targeted TLA into
neighboring lung areas through intersegmental collateral
channels.
[0020] Still in accordance with the preferred embodiment of the
present invention, after a predominant concentration of DLMW gas is
reached in the TLA the, DLMW gas pressure in the TLA is regulated
to an elevated but safe level above the pressure in neighboring
lung areas so as to create a pressure gradient favorable to gas
transfer out of the TLA into neighboring areas through tissue,
collateral channels and, if available, vasculature. This is
accomplished by instilling additional DLMW gas. Typical TLA
pressures are initially set at 10-25 cmH.sub.2O or 25-50 cmH.sub.2O
in spontaneously breathing patients or mechanically ventilated
patients respectively thus creating an initial mean pressure
gradient between the targeted TLA and neighboring compartments of
approximately 20 cmH.sub.2O. The elevated TLA pressure also
prevents influx of respiratory gases through collateral channels or
other sources. Gradually, the amplitude of the pressure gradient is
lowered by regulation of the TLA pressure and controlling the
amount of new DLMW gas delivery via the catheter. First, because of
the net efflux of gas out of the lobules through interconnecting
channels in the alveoli (pores of Kohn) and terminal bronchioles
(Lambert's canals) and then out of the TLA through intersegmental
channels the lobules begin to reduce in size causing an overall
shrinkage and consolidation of tissue, thus decreasing the
diffusivity of the tissue to influx of larger molecule respiratory
gases (such as CO.sub.2 and N.sub.2). Eventually, alveoli and
entire lobules collapse thus substantially deflating the TLA and
after further consolidation, the tissue and intersegmental
collateral channels become non-diffusible to incoming respiratory
gases. Further, due to the surface tension of the collapsed air
pockets they resist re-opening and long term and/or permanent
collapse is possible. The duration of this diffusion/deflation
procedure is controlled to obtain a slow rate of deflation such
that the resultant tissue shear forces are benign and atraumatic
and such that even the DLMW gas in the bullae has sufficient
duration to effuse. This is expected to take between 1 hour and 30
days, most typically 7 to 14 days depending on the size of the TLA
compartment, the size and number of bulla, the level and
variability of the disease, and the selected desufflation
parameters. The duration is designed and controlled such that the
rate of deflation is about the same rate of tissue remodeling, such
that the two can occur concurrently thus mitigating shear induced
injury.
[0021] In an additional embodiment of the present invention,
regulation of the TLA pressure, during the native gas displacement
phase and/or during the DLMW gas diffusion/deflation phase, is
further facilitated by occluding the annular space between the
catheter and the feeding bronchus of the TLA. This embodiment
further facilitates control of the pressure and gas concentration
in the TLA particularly in gravitationally challenging situations.
In a yet additional embodiment of the present invention, the
pressure profiles of DLMW gas delivery and respiratory gas exhaust
are regulated to be either constant, variable, intermittent,
oscillatory, or synchronized with the patient's breathing pattern.
It can be appreciated that the possible combinations of pressure
profiles are extensive, but all must comply with the following
fundamental and critical principle that is unique to the present
invention: The pressure profiles must create and maintain a
pressure gradient of higher pressure in the TLA than that in
neighboring areas for extended periods to facilitate more gas
efflux then influx and must keep the hundreds of small distal
airways open thus creating sustained communication with the
otherwise trapped gas in the distal spaces during the various
phases of the desufflation procedure.
[0022] Still in accordance with the preferred embodiment of the
present invention, the proximal end of the catheter is kept
external to the patient and is connected to a desufflation gas
control unit (DGCU). The DGCU comprises a supply of DLMW gas, or
alternately an input connection means to a supply thereof, and
comprises the requisite valves, pumps, regulators, conduits and
sensors to control the desired delivery of the DLMW gas and to
control the desired pressure in the TLA. The DGCU may comprise a
replaceable or refillable modular cartridge of compressed
pressurized DLMW gas and/or may comprise a pump system that
receives DLMW gas from a reservoir and ejects the DLMW gas into the
TLA through the catheter at the desired parameters. The DGCU
further comprises fail-safe overpressure relief mechanisms to avoid
risk of lung barotrauma. The DGCU may also comprise a negative
pressure generating source and control system also connectable to a
lumen in the catheter for the previously described facilitation of
native gas exhaust. The DGCU may be configured to be remove-ably or
permanently attached to a ventilator, internally or externally, or
to be worn by an ambulatory patient. It is appreciated that the
DGCU will have the requisite control and monitoring interface to
allow the user to control and monitor the relevant parameters of
the desufflation procedure, as well as the requisite power source,
enclosure, etc.
[0023] It should be noted that in some embodiments of this
invention, desufflation is performed during mechanical ventilation
to more effectively ventilate a patient, for example to assist in
weaning a patient from ventilatory support. Still in other cases,
desufflation is performed as a chronic therapy either continuously
or intermittently on a naturally breathing patient. In this later
embodiment, the catheter may be removed after a treatment while
leaving a hygienic seal at the percutaneous access point, and a new
catheter later inserted for a subsequent treatment. Still in other
embodiments of this invention, it is necessary to restrain the TLA
from re-expansion in order to achieve the desired clinical result,
such as but not limited to a bronchial plug, a tissue tether or a
tissue clamp. It should also be noted that the desufflation
procedure may be performed simultaneously on different lung areas
or sequentially on the same or different lung areas. Finally it
should be noted that the desufflation procedure can be performed on
a relatively few large sections of lung, for example on one to six
lobar segments on patients with heterogeneous or bullous emphysema,
or can be performed on many relatively small sections of lung, for
example on four to twelve sub-subsegments on patients with diffuse
homogeneous emphysema.
[0024] The basic scientific principles employed to accomplish
desufflation are the physical laws of mass transfer, i.e., gas and
tissue diffusivity, concentration gradients and pressure gradients,
and the physical laws of collapsible tubes. As can be seen in a
review of the prior art, no methods currently exist wherein a lung
area hyperinflated with trapped CO.sub.2-rich gas is deflated by
creating and maintaining an elevated positive pressure in the said
area with diffusible gas nor wherein the said area is deflated by
pressurizing the airways in the area to push gas out of the treated
area through collateral pathways.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 describes a partial cross sectional view of a
patient's chest and lungs describing the lung anatomy.
[0026] FIG. 1a describes a cross sectional view of the lung showing
placement of the desufflation catheter in a lung bronchi.
[0027] FIG. 1b describes the delivery, exhausting, and diffusion of
the diffusible low molecular weight gas in the treated lung
area.
[0028] FIG. 1c describes an emphysematous lung area with enlarged
poorly defined alveoli.
[0029] FIG. 1d describes a healthy lung area with properly sized
and well defined alveoli.
[0030] FIG. 2A describes the gas transfer and gas flux physics
governing desufflation.
[0031] FIG. 2B describes the physiologic mathematical formula
governing the invention.
[0032] FIG. 3a graphically shows the diffusible gas delivery flow
rate being delivered into the treatment area during the gas wash
out stage and the volume reduction stage.
[0033] FIG. 3b graphically shows the diffusible gas delivery
pressure being delivered into the treatment area during the gas
wash out stage and the volume reduction stage
[0034] FIG. 3c graphically shows the gas pressure in the treatment
area during the gas wash out stage and the volume reduction
stage.
[0035] FIG. 3d graphically shows the increasing and decreasing
diffusible and respiratory gas concentrations in the treatment
area, during the gas wash out stage and the volume reduction
stage.
[0036] FIG. 3e graphically shows the residual volume reduction of
the treatment area during the gas wash out and volume reduction
stages.
[0037] FIG. 4a graphically describes the diffusible gas flow and
pressure delivery at constant amplitude.
[0038] FIG. 4b graphically describes the delivery of diffusible gas
with an intermittent delivery cycle.
[0039] FIG. 4c graphically describes the delivery of diffusible gas
with a positive pressure alternating with the removal of mixed gas
using a negative pressure.
[0040] FIG. 4d graphically describes oscillatory delivery of
diffusible gas, alternating with negative pressure removal of mixed
gases.
[0041] FIG. 4e graphically describes a continuously adjusting
delivery level of diffusible gas.
[0042] FIG. 4f graphically describes simultaneous positive pressure
delivery of diffusible gas with vacuum removal of mixed gases.
[0043] FIG. 4g graphically describes simultaneous constant
amplitude delivery of diffusible gas with oscillatory vacuum
removal of mixed gases.
[0044] FIG. 4h graphically describes increasing and decreasing
slopes of diffusible gas delivery.
[0045] FIG. 4i graphically describes a constant amplitude delivery
of diffusible gas during the gas wash out stage and a decreasing
amplitude delivery during the volume reduction stage.
[0046] FIG. 4j graphically describes diffusible gas delivery
synchronized with the breathing cycle.
[0047] FIG. 5a depicts the various gas flow pathways for influx and
efflux of gases
[0048] FIG. 5b depicts a catheter with a non-occlusive anchor.
[0049] FIG. 5c depicts a catheter with an intermittently inflatable
occlusive anchor and with gas delivery and gas removal lumens.
[0050] FIG. 5d depicts a catheter with an intermittently inflatable
occlusive anchor and with a shared lumen for gas delivery and
removal.
[0051] FIG. 5e depicts a catheter with concentric lumens with a gas
delivery inner lumen and a gas removal outer lumen.
[0052] FIG. 6 describes a typical desufflation catheter.
[0053] FIG. 7 describes different catheter anchoring
configurations.
[0054] FIG. 7a describes a non-occlusive wire basket catheter
anchor.
[0055] FIG. 7b describes an inflatable non-occlusive catheter
anchor.
[0056] FIG. 7c describes an intermittently inflatable and occlusive
anchor.
[0057] FIG. 7d describes a combination non-occlusive wire basket
catheter anchor and an intermittently inflatable occlusive
anchor.
[0058] FIG. 7e describes a catheter with an inner member with a
non-occlusive anchor.
[0059] FIG. 8 is a general layout of desufflation being performed
on a ventilatory dependent patient.
[0060] FIG. 9 is a general layout of desufflation being performed
on an ambulatory spontaneously breathing patient.
[0061] FIG. 9a is a cross sectional view showing a sealing and
securing sleeve at the catheter access site into the patient.
[0062] FIG. 10 describes the general layout of the desufflation
pneumatic control unit (PCU).
[0063] FIG. 11 describes a desufflation procedure kit.
DETAILED DESCRIPTION OF THE INVENTION
[0064] Referring to FIGS. 1-1d the desufflation procedure is
summarily described being performed in an emphysematous lung. FIG.
1 shows the left 30 and right 31 lung, trachea 32, the left main
stem bronchus 33, the five lung lobes 36, 37, 38, 39, 40, a lateral
fissure 41 separating the left upper and lower lobe, and the
diaphragm 42 which is displaced downward due to the hyperinflated
emphysematous lung. Detail A in FIG. 1a shows a cut away view in
which the upper left lobe bronchus 43, the apical segmental
bronchus 44 of the left upper lobe, the parietal pleura 45, the
visceral pleura 46, the pleural cavity 47, a large bulla 48 and
adhesions 49. Bullae are membranous air vesicles created on the
surface of the lung between the visceral pleura 46 and lung
parenchyma 51 due to leakage of air out of the damaged distal
airways and through the lung parenchyma. The air in the bullae is
highly stagnant and does not easily communicate with the conducting
airways making it very difficult to collapse bullae. Pleural tissue
adhesions 49 are fibrous tissue between the visceral pleura 46 and
the parietal pleura 45 which arise from trauma or tissue fragility.
These adhesions render it difficult to acutely deflate an
emphysematous hyperinflated lung compartment without causing tissue
injury such as tearing, hemorrhage or pneumothorax. Detail B in
FIG. 1b describes the bronchi 44 of the left upper lobe apical
segment 52 and a separation 53 between the apical segment and the
anterior segment 54. Detail D in FIG. 1d a non-emphysematous lung
lobule is shown which includes the functional units of gas
exchange, the alveoli 55, and CO.sub.2-rich exhaled gas 58 easily
exiting the respiratory bronchiole 56, Also shown are
intersegmental collateral channels 57, typically 40-200 um in
diameter, which communicate between bronchopulmonary segments
making it difficult for a lung compartment to collapse or remain
collapsed because of re-supply of air from neighboring compartments
through these collateral channels. Detail C in FIG. 1c describes an
emphysematous lung lobule in which the alveolar walls are destroyed
from elastin breakdown resulting in large air sacks 59. The
emphysematous lobule traps air becoming further hyperinflated
because the respiratory bronchiole leading to the engorged lobule
collapses 60 during exhalation, thus allowing air in but limiting
air flow out 61.
[0065] FIGS. 1, 1a, 1b also shows the desufflation catheter 70
anchored in the apical segment bronchus 44. In FIG. 1b, DLMW gas 71
is shown being delivered by the desufflation catheter 70. The
native gas 72 in the targeted apical segment is forced out of the
apical segment 52, both proximally alongside the catheter 70 and
also across intersegmental collateral channels into the neighboring
anterior segment 54 then proximally up the airways. The DLMW gas 71
also is forced through the intersegmental collateral channels in
the same manner. The application and maintenance of a pressure
gradient of a higher but safe pressure in the treated area compared
to the neighboring area assures that the bronchioles in the treated
area do not collapse during the procedure so that air is not
trapped in the distal areas.
[0066] Now referring to FIGS. 2A and 2B, a mass transfer schematic
78 and mathematical model 79 is shown describing the governing
physics and the fundamental importance of the pressure and
concentration gradient that is critical to the desufflation
procedure. DLMW gas is delivered to the targeted lung area 80 and
native gas and DLMW gas effuses into the neighboring lung areas
81.
[0067] FIG. 3 describes the DLMW gas flow delivery, gas
concentration and gas volume profiles for a typical desufflation
procedure. FIGS. 3a and 3b describe the delivered DLMW gas flow and
pressure respectively during the gas wash out phase 85 and 87,
which may be a constant amplitude and during the deflation phase 86
and 88, when the gas flow and pressure is reduced over time.
[0068] FIG. 3c describes the resultant gas pressure that is created
by desufflation in the targeted lung area 89 which is typically
maintained at level higher than the gas pressure in neighboring
lung areas 90. During the deflation phase the targeted lung area
pressure is reduced 91 as deflation occurs.
[0069] FIG. 3d describes the gas concentration in the targeted lung
area wherein the native gas concentration 92 attenuates while the
DLMW gas concentration 93 increases. During the deflation stage,
the DLMW gas concentration 95 is close to 100% and the native gas
concentration 94 is close to 0%.
[0070] FIG. 3e describes the targeted area gas volumes which are
initially very high due to the disease, and are kept high during
the gas wash out phase 96 with the installation of DLMW gas. During
the deflation stage, after most of the native gas is washed out,
the targeted area gas volume is regulated downward 97 as the
positive pressure of DLMW gas delivery is regulated downward.
[0071] Now referring to FIG. 4, different optional desufflation gas
pressures and flow profiles are described. In FIG. 4a after the
start of the desufflation procedure 100 the gas flow 101 and
resultant gas pressure 102 are shown at constant amplitude. In FIG.
4b an intermittent delivered flow is shown indicating an on 103 and
off 104 period. FIG. 4c describes an alternating positive pressure
105 and negative pressure 106 delivery. FIG. 4d describes an
oscillating 107 pressure or flow delivery. FIG. 4e describes a DLMW
gas flow delivery that is continuously adjusted 108 in order to
maintain a constant level positive pressure 109 in the targeted
lung area. FIG. 4f describes simultaneous positive pressure
delivery of DLMW gas 110 and application of vacuum 111 to exhaust
mixed gases from the targeted lung area. FIG. 4g describes constant
level DLMW gas delivery 112 simultaneous with intermittent or
oscillatory vacuum application for exhaust 113. FIG. 4h describes
an ascending and descending waveform 114 of DLMW gas pressure or
flow delivery. FIG. 4I describes the gas wash out stage of DLMW gas
delivery 115 where the delivered pressure may be constant and the
deflation stage of DLMW gas delivery 116 where the delivered
pressure may be reduced. FIG. 4j describes DLMW gas delivery that
is synchronized with the patient's breathing; In this case DLMW gas
is delivered during exhalation 117 and delivery is interrupted
during inspiration 118.
[0072] Desufflation pressure is typically regulated below 50
cmH.sub.2O to avoid barotrauma and to avoid inadvertent creation of
bulla and to avoid creating inadvertent embolism in the
vasculature, and typically above 10 cmH.sub.2O in order to maintain
the requisite pressure gradient. The duration for native gas
displacement typically ranges from 1 hour to 14 days depending on
the lung area size and number of bulla. The duration for DLMW gas
effusion/deflation is typically regulated to take from 1 day to 30
days, depending on the lung area size and number of bulla, such
that neighboring lung tissue has sufficient duration to remodel
simultaneously with targeted area deflation, to avoid tissue injury
caused by rapid collapse.
[0073] Now referring to FIG. 5, gas flow pathways and alternative
catheter configurations for the desufflation procedure are
described in more detail. FIG. 5a graphically describes the gas
flow pathways for influx and efflux of gases. DLMW gas is delivered
130 into the targeted lung area via the catheter. Also, some
respiratory gases from breathing 131 continue to enter the targeted
lung area during the procedure although at a reducing rate over
time since the area will become filled with DLMW gas 130. Some of
the delivered DLMW gas escapes from the targeted area around the
catheter 132 proximally out the airways proximal to the targeted
area. The majority of native gases in the targeted area are forced
out proximally around the catheter 133 and this efflux of native
gases dramatically reduces over time because the content of native
gas in the targeted area is significantly reduced. Meanwhile, gases
are forced out of the targeted area through collateral channels
into neighboring lung areas since the desufflation parameters have
created a pressure gradient in that direction. Native gas effusion
through collateral channels 135 reduces towards zero in the gas
wash out stage of the procedure, while DLMW gas effusion through
collateral channels 134 remains constant during the gas wash out
stage and is deliberately reduced during the deflation stage as the
desufflation parameters are appropriately regulated.
[0074] FIGS. 5b, 5c, 5d and 5e depict alternate catheter
configurations corresponding to alternative means of controlling
the desufflation parameters. FIG. 5b depicts a catheter with a
non-occlusive anchor 150 and single lumen 151 for DLMW gas
infusion, mixed gas evacuation occurring around the catheter 152.
FIG. 5c depicts a catheter with an occlusive anchor 153 and with
separate lumens for DLMW gas infusion 154 and mixed gas evacuation
155. FIG. 5d depicts a catheter with an occlusive anchor 156
wherein DLMW gas infusion and mixed gas evacuation is conducted
through a common lumen 157 by alternating between infusion and
exhaust. FIG. 5e describes a catheter with a infusion lumen 158 and
ports 159 for application of vacuum 160 to be applied to
neighboring bronchi 162 to facilitate efflux of gas 161 out of the
targeted lung area via collateral channels. It can be appreciated
that many configurations of lumens, occlusive anchors and pneumatic
parameters can be combined in many ways to achieve different
optional desufflation techniques.
[0075] Now referring to FIG. 6, a typical desufflation catheter -
is described including a DLMW gas flow lumen 171, optionally an
exhaust gas lumen 172, a non-occlusive anchoring means 173 and a
sleeve 174 for collapsing the anchoring means, a slide mechanism
169 and lumen for the mechanism 168 for retracting the sleeve 174,
a connector at its proximal end for attachment to a and a supply of
DLMW gas 175 and optionally a vacuum source 176, a tensioning or
sealing means 177 with a sealing ring 179 for tensioning and
optionally sealing at the point of entry into the patient, and a
connection means 178 near the proximal end for detachment of the
proximal end from the shaft, for example if removing an endoscope
from over the catheter or for interrupting the therapy while
leaving the distal end of the catheter in-situ.
[0076] FIG. 7 depicts alternative anchor configurations. FIG. 7a
describes a radially expanding and compressible wire coil anchor
180 in which the wires 181 are braided to create a cylindrical
structure that does not occlude the airway. FIG. 7b describes a
radially inflatable anchor with spokes 182 such that the anchor
does not occlude the airway. FIG. 7c describes a radially expanding
inflatable anchor such as a cuff or balloon 183 which occludes the
airway while anchoring. FIG. 7d describes a catheter with an
occlusive sealing member 184 which can be continuously or
intermittently inflated to facilitate regulation of the
desufflation parameters in the TLA, and a non-occlusive anchor 185
to continuously anchor the catheter in the airway for extended
periods. FIG. 7e describes an outer 186 and inner 187 catheter
configuration wherein the inner catheter 187 is axially slide-able
with respect to the outer catheter 186 and wherein the inner
catheter includes a radially expandable anchoring member 188, such
as a wire basket, for securing the catheter in position for
extended periods. The inner catheter in this embodiment may include
a thermoplastic material or may alternately include a metallic
construction such as a guide wire.
[0077] Typical diameters of the desufflation catheter depend on the
lung area being targeted. Some exemplary dimensions follow: Lobar
segment: OD=2.0-3.5 mm; Lobar subsegment: OD=1.5-2.5 mm; Lobar
sub-subsegment: OD=0.5-1.0 mm. DLMW gas insufflation lumen
diameters are typically 0.25-1.0 mm and gas exhaust lumens, if
present, are typically comprise an area of 0.8-4.0 mm.sup.2,
preferably greater than 2.0 mm.sup.2 to avoid mucus plugging.
Catheter lengths are typically 120-150 cm. Anchoring forces are
typically 1-10 psi and occlusion forces, if present, are typically
0.2-0.5 psi. Proximal entry point tensioning forces typically
produce 0.5-1.5 lbs of axial tension. Anchors and occlusive member
diameters depend on the targeted bronchial level and are up to 20
mm for lobar bronchi, 15 mm for segmental bronchi and 5 mm for
sub-subsegmental bronchi when fully expanded. Some examples of
catheter materials are: the shaft extrusion comprised of a
thermoplastic or thermoset material, such as nylon, PVC,
polyethylene, PEBAX, silicone; the non-occlusive anchor comprised
of a stainless steel or Nitinol wire; the inflatable occlusive
member comprised of a highly compliant plastisol, silicone or
urethane; connectors typically comprised of PVC, polysulfone,
polypropylene or acrylic.
[0078] FIG. 8 describes a general layout of the present invention,
wherein Endotracheal Trans-luminal Bronchopulmonary Compartment
Desufflation (ETBCD) is performed on a ventilatory dependent
patient, showing catheterization of the targeted TLA 250, entry of
the catheter 170 through an endotracheal tube 252, connection of
the proximal end of the catheter 253 to the desufflation pneumatic
control unit (PCU) 254, as well as the ventilator 255 and breathing
circuit 256. It can be seen that the catheter distal end is
anchored 257 in the targeted lung area bronchus and the section of
catheter at the patient entry point is tensioned to prevent
inadvertent unwanted movement with a tensioning and/or sealing
means 177.
[0079] FIG. 9 describes a general layout of the present invention,
wherein Percutaneous Trans-luminal Bronchopulmonary Compartment
Desufflation (PTDCD) is performed on an ambulatory spontaneously
breathing patient, showing catheterization of the targeted TLA with
the desufflation catheter 170, distal end anchoring 261, entry of
the catheter either nasally 262 or through a percutaneous incision
263, connection of the proximal end of the catheter to the wearable
portable PCU 254. Referring to FIG. 9a a cross-sectional view is
shown of entry of the catheter into the patient showing a hygienic
seal 177 and a seal securing means 266 attached to the neck of the
patient. The hygienic seal also prevents inadvertent unwanted axial
movement of the catheter but allows desired axial sliding of the
catheter in response to anticipated patient movement. The seal can
be left in place to temporarily seal the incision with a
self-sealing membrane or attaching a plug 267 if the catheter is
removed for extended periods.
[0080] Now referring to FIG. 10 the Desufflation Pneumatic Control
Unit 339 (PCU) is shown in more detail, including a DLMW gas source
340, an insufflation pressure regulator 341, control valve 342, and
overpressure safety relief valve 343, a check valve 344, a pressure
sensor 355, and a self-sealing output DLMW gas connector 345. Also
exemplified is a vacuum supply system comprised of a vacuum source
346, vacuum regulator 347, control valve 348, check valve 349,
pressure sensor 356 and CO.sub.2 sensor 357. A replaceable or
refillable modular cartridge of DLMW gas 351 is shown as an
alternative supply, typically housing 100-500 ml of compressed DLMW
gas. For example a cartridge containing 250 ml of compressed DLMW
gas pressurized at 1 Opsi would enable delivery of DLMW gas at a
rate of 10 ml/hour at an output pressure of 25 cmH.sub.2O for 20
days, based on ideal gas laws, and assuming 30% losses due to
system leakage. A pump system 352 is shown as an alternative to a
pressurized source in which case the DLMW gas is fed into the pump
from the outside source and pumped out into the catheter at the
desired output parameters.
[0081] FIG. 11 describes a desufflation procedure kit, including
the desufflation catheter 170, optionally an inner catheter or
guide wire 187, a tensioning connector 177, a securing strap 266, a
hygienic tracheotomy plug 267, a bronchial plug 335 to prevent
re-inflation of the desufflated lung area, a desufflation pneumatic
control unit 339 with a holster 338, a cartridge of DLMW gas 351,
pre-conditioning solutions 336, and an instruction sheet 337.
[0082] It should be noted that the above preferred embodiments of
the present invention are exemplary and can be combined in mixed in
ways to create other embodiments not specifically described but
which are still part of this disclosure. For example, the catheter
occlusive anchor can be detachable from the catheter so that after
the desufflation procedure is complete, the catheter can be
retracted from the airway, leaving the occlusive member in place
which self seals in the airway thus preventing re-expansion of the
treated area.
[0083] In addition, the method and device may include the following
elements. It may displace the native gas in a lung area with a
diffusible low molecular weight (DLMW) gas and optionally reducing
the volume of said lung area, including: An indwelling catheter may
be placed in a bronchus feeding said lung area wherein said
catheter is anchored in said bronchus for an extended period; DLMW
gas may be delivered into said lung area through said catheter for
extended periods; An exhaust pathway may be maintained for escape
of said native and DLMW gases out of said lung area over extended
periods. An anchor may permit said catheter to remain in place
automatically for said extended periods without the supervision of
a person. DLMW gas may be delivered at a positive pressure, wherein
said pressure is typically 2-20 cwp greater than gas pressure in
neighboring lung areas. DLMW gas delivery may be regulated to
create a pressure in said lung area that is at least temporarily
greater than the gas pressure in neighboring lung areas, and
further wherein said pressure is typically 2-20 cwp and preferably
5-10 cwp greater than said neighboring area gas pressure. DLMW gas
delivery may be regulated to create a pressure in said lung area
greater than the gas pressure in said neighboring areas, and
further wherein said pressure in said lung area is reduced over
time until said pressure equals pressure in said neighboring areas.
A catheter may be placed through the user's upper airway while the
user is spontaneously breathing, such as the oro-nasal passage, a
cricothyrotomy or a tracheotomy, or through an artificial airway
such as but not limited to a tracheal tube. Multiple lung areas may
be treated either simultaneously or sequentially. The lung may be
treated at the lobar, segmental, subsegmental or sub-subsegmental
bronchi level. The catheter may be positioned with visual
assistance, such as with endoscopy or floroscopically and
optionally positioned with the assistance of a guide wire or inner
guiding catheter.
[0084] The method and device may include a catheter that does not
occlude the feeding bronchus of said lung area, or wherein said
catheter occludes said feeding bronchus of said lung area, either
intermittently or continuously. The DLMW gas may be delivered
continuously at a constant or variable flow or pressure amplitude.
The DLMW gas may be delivered non-continuously, such as but not
limited to an oscillatory flow pattern, a flow pattern synchronized
with the patient's breath cycle, or an intermittent pattern. Gas
exhaust may occur passively around the outside of said catheter or
through a lumen inside said catheter or through intersegmental
collateral channels into neighboring lung areas. Gas exhaust may be
actively assisted by the application of vacuum to said area through
a lumen in said catheter, wherein said vacuum is applied either
continuously, intermittently or synchronized with the patient's
breathing cycle. Gas exhaust may be augmented by the application of
vacuum to neighboring lung areas, thereby augmenting said gas
exhaust through intersegmental collateral channels from said lung
area into said neighboring lung areas. Gas exhaust and gas delivery
may be conducted through at least one lumen in said catheter. The
feeding bronchus may be occluded intermittently to facilitate said
delivery of DLMW gas and displacement of resultant mixed gases.
[0085] The method and device may include DLMW gas that possesses
greater diffusivity or lower molecular weight than that of said
native gas, said molecular weight typically 2-20 and preferably
4-10, such as but not limited to Helium, Helium-oxygen mixtures and
nitric oxide, and or a diffusivity of 10-4 cm2/sec. The DLMW gas
delivery may be performed acutely, typically 30 minutes to 24
hours. sub-chronically, typically one to 14 days or chronically,
typically 14 to 90 days and optionally performed for periods
greater than three months wherein said delivery is optionally
interrupted intermittently. A therapeutic agent may be delivered to
said targeted area after said native gas wash out. The method and
device may reduce the volume of a lung area by delivering via a
catheter a positive pressure of DLMW gas into a said lung area and
creating a positive pressure of DLMW gas in said area, said
positive pressure being predominantly greater than the pressure in
neighboring lung areas. The positive pressure of DLMW gas may be
created by delivering said DLMW gas via a catheter into said area,
and wherein said gas delivery is regulated to achieve at least
temporarily a desired pressure level typically 2-20 cwp and
preferably 5-10 cwp greater than the gas pressure in neighboring
areas, and wherein said delivery is performed over extended periods
typically one hour to 90 days and preferably one to seven days, and
further wherein said delivery can be continuous, oscillatory or
intermittent and can be constant amplitude or non-constant
amplitude. The gas exhaust and gas delivery may be alternated
through a common lumen in said catheter. The gas exhaust and gas
delivery may be each conducted through dedicated lumens in said
catheter. The DLMW gas delivery may be performed acutely typically
for 30 minutes to 24 hours, sub-chronically typically for one to 14
days, or chronically for over 14 days or for an indefinite
period.
[0086] The methods and devices may reduce the volume of a lung area
by: Catheterizing said lung area with an indwelling catheter for an
extended period; wherein said catheter is anchored to remain in
place for said period automatically without supervision of a
person; the native gas in said lung area may be displaced by
delivering a DLMW gas in said area via said catheter and
maintaining an exhaust pathway over extended periods for the escape
of said native and DLMW gases; the pressure of said DLMW gas
delivery into said lung area may be regulated to create a gradient
of higher gas pressure in said lung area compared to gas pressure
in neighboring lung areas, said gradient sufficient to inhibit
infusion of gases into said lung area from neighboring lung areas,
and to force effusion of said delivered DLMW gas out of said area,
said effusion sufficient to effect at least partial volume
reduction of said lung area.
[0087] The amplitude of said gradient may be reduced over time to
facilitate at least partial deflation of said lung area. The
catheter may be placed through the user's upper airway. The target
bronchus may be a lobar, segmental, subsegmental or
sub-subsegmental bronchi. The volume reduction of said area may be
restrained from re-expansion by the application of a restraint,
such as but not limited to a bronchial plug, a tether or a tissue
clamp. The apparatus may displace native gas from or reduce the
volume of a lung area, and comprise: A catheter with a distal and
proximal end with at least one lumen for fluid flow, wherein the
distal end is positioned in said lung area and wherein the said
proximal end is positioned outside the body, said catheter entering
the body at a point of entry, said catheter further comprising: (1)
At least one lumen for the delivery of gas; (2) At its distal end
an anchoring member to anchor the distal tip of the catheter in a
bronchial lumen for extend periods while the catheter is
unattended; (3) between its distal and proximal ends a securing
means for securing said catheter shaft to said point of entry to
the body; (4) at its proximal end a connection means for connection
to a gas source external to the patient; (5) A pneumatic control
unit comprising: A supply of DLMW gas or connection means to
thereof, a connection means for connection to the proximal end of
said catheter to couple said gas with the gas flow lumen in said
catheter, a pressure delivery and regulation means to produce and
regulate a desired output of said DLMW gas; A user interface for
control and display.
[0088] The distal end of the catheter may comprise both a
non-occlusive anchor for anchoring is said bronchus, and a radially
inflatable occlusive member which comprises a means to
intermittently inflate to occlude the annular space around said
catheter in the said area's feeding bronchus, and optionally
wherein said catheter and said pneumatic control unit automatically
work in unison such that said inflation and occlusion is
synchronized with said DLMW gas delivery. The anchoring member may
be a radially compressible structure with a resting diameter
concentric to said catheter shaft typically 2-20 mm in diameter,
such as but not limited a wire structure attached to the shaft of
said catheter, such as but not limited to a wire framed cylindrical
or spherical structure, such as but not limited to straight
non-crossing wires, woven wires and braided wires. The catheter may
comprise an outer concentric sleeve wherein said sleeve is axially
slide-able with respect to said catheter shaft and further wherein
said anchoring member is compressed into a radially collapsed state
between said catheter shaft and said sleeve and further wherein
upon moving said catheter or said sleeve axially, said anchoring
member is released and freely radially expands towards its resting
diameter, said expansion producing tension against said bronchial
wall, said tension typically 0.5-3.0 lbs force and preferably
0.75-1.5 lbs force. The catheter anchoring member may be an
inflatable member and further wherein said catheter comprises an
inflation or deflation means for elective inflation. The catheter
anchoring member may occlude said bronchus intermittently wherein
said pneumatic control unit comprises a means to synchronized
delivery of said DLMW gas with said occlusion of said bronchus. The
catheter may comprise an outer catheter and an inner catheter
wherein said inner catheter includes said non-occlusive anchor at
its distal end wherein said inner catheter and anchor protrudes
from the distal tip of said outer catheter. The distal end of said
catheter may be branched for simultaneous cannulation of multiple
bronchi. The catheter shaft may comprise a de-coupling means, said
means permitting a disconnection of the proximal end of said
catheter from balance of said catheter. The catheter shaft may
comprise a concentric connection means, said means further
comprising an anchoring feature at the point of entry to the body
and optionally providing a sealing feature at the point of entry to
the body. The catheter may comprise a second lumen through which
gas is exhausted either passively or actively with the application
of vacuum. The catheter may comprise an outer diameter of typically
0.5-4.0 millimeters, most preferably 2-3 millimeters and a gas
delivery lumen of typically 0.25-2 millimeters, most preferably 0.5
millimeters, and optionally comprising a gas exhaust lumen of a
diameter of typically 0.25-3 millimeters, most preferably 2
millimeters, and further comprising a length of typically 80-200
centimeters, most preferably 100-140 centimeters.
[0089] The pneumatic control unit may comprise manual or automatic
controls for producing constant, intermittent or oscillatory DLMW
gas delivery patterns, and optionally for producing constant,
intermittent or oscillatory gas exhaust patterns, typically for the
purpose of maintaining a desired pressure in said targeted lung
area. The pneumatic control unit may comprise controls to
synchronize said DLMW gas delivery and optionally said gas exhaust
with the patient's breathing pattern. The targeted lung area
pressure may be measured using a pressure sensing means, either at
or near to the distal end of the said catheter, or by measuring
pressure near the proximal end of said catheter to calculate said
catheter distal end pressure, for example using Poiseuille's Law.
The pneumatic control unit may comprise a gas concentration
measuring means, wherein said means is used to determine the
completeness of native gas displacement and for regulation of said
pneumatic parameters. The pneumatic control unit may be integral to
and or re-movably attachable to a mechanical ventilator and
optionally includes a replaceable or refillable DLMW gas cartridge.
The pneumatic control unit may be portable and wearable by the
user, for example with a belt clip, fanny pack or shoulder strap
and optionally includes a replaceable or refillable DLMW gas
cartridge. The system may comprising a kit, the kit comprising said
indwelling DLMW gas delivery catheter, optionally including an
outer sleeve and inner guiding catheter, a pneumatic gas control
unit, a portable strap, optionally a quantity of DLMW gas,
pre-conditioning agents, optionally a bronchial plug, a hygienic
tracheotomy plug, a tensioning connector, and an instruction sheet.
The targeted lung area may be pre-conditioned with a substance to
make it less susceptible to infection and more susceptible to
deflation, such as with mucolytic agents, bronchodilators,
antibiotics, surface tension modifiers, and tissue diffusivity
modifiers.
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