Abstract:
The invention provides methods of performing lung volume reduction to treat a patient. One aspect of the invention provides a method of compressing a first portion of a lung of a patient including the following steps: providing a vent connecting the first portion of the lung to the exterior of the patient; isolating the first portion of the lung from a second portion of the lung adjacent the first portion; and delivering pressurized fluid to the second portion of the lung to compress the first portion of the lung.

Description:
CROSS-REFERENCE 
   This application claims the benefit of U.S. Provisional Application No. 60/580,565, filed Jun. 16, 2004, which is incorporated herein by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   The primary role of the lung is to perform the function of breathing which assists in the intake of oxygen and removal of carbon dioxide from the body. The oxygen in air is inhaled through the mouth and trachea to the main bronchi. The bronchi divide at the end of the trachea into the left and right main bronchi and these respectively divide into bronchial branches, which “feed” the three lobes of the lung on the right and two on the left. These bronchi continue to subdivide into bronchioles (smaller bronchi), over twenty three times in total. The over 100,000 bronchioles get smaller in diameter and ultimately terminate in over 300 million air sacs, called alveoli. The alveoli, which are clustered like grapes, are approximately 0.3 mm in diameter and provide a huge surface area for gas exchange to take place. There are capillaries surrounding the alveoli and this is where the inspired oxygen is diffused into the vascular system of the body. Likewise, toxic CO 2  is diffused into the alveoli from the capillaries and is removed from the body during expiration. 
   With no external loads, the lung structure is approximately the size of a grapefruit. It is expanded larger in the chest cavity with a physiologic level of vacuum that stretches it to the chest wall. As we inhale, we are forcing the lung cavity to a larger condition by flexing the ribs and lowering the diaphragm. The vacuum around the lungs pull the lung volume larger as the chest volume is increased; air pressure in the lung is reduced and atmospheric air pressure forces air into the lung. During expiration, the diaphragm and ribs are relaxed to allow the elastic properties of the lung to pull the chest cavity to a smaller volume and to force air out of the lungs. 
   Chronic Obstructive Pulmonary Disease (“COPD”) is a progressive disease that causes lung parenchyma to lose elastic properties and lose surface area that is required to exchange gas such as O 2  and CO 2 . Lung tissue is eroded to leave large holes, typically in the upper lobes. The holes do not contribute to the elastic pulling forces required during expiration. Areas adjacent to the holes are more highly stressed. The stressed tissue stretches and loses recoil properties. These stretched regions fail to pull on and thus fail to suspend the major airways in a radial fashion to hold them open. As the disease progresses, the patient will eventually need to force expiration, which causes the major airways to collapse and block air flow. This effect is exacerbated with additional applied expiration pressure since the airways are ill-supported. During inspiration, these unsupported regions fill preferentially since they are floppy and have no resistance to expand (no elasticity). They preferentially consume the oxygenated air even though there is little remaining surface area to exchange O 2  to the bloodstream. 
   Normal lungs rarely present with collateral flow paths between lobules and between major lobes of the lung in the form of pores and leak paths. In COPD patients, damaged tissue forms vacuoles or holes, which grow in size (e.g., 2 μm to over 500 μm) and multiply to allow flow from numerous airway paths to supply these regions with air. As this tissue degradation occurs, numerous holes communicate with each other, and eventually the lobes communicate with each other, through means other than the normal airways. 
   Lung volume reduction surgery (LVRS) is a procedure where the chest is opened and a target region of lung is cut out. This accomplishes several things. It removes damaged regions that contribute very little to gas exchange. More importantly, it removes lung volume so that the healthy portion of the lung that remains can be expanded beyond typical physiologic volume (expand healthy functioning alveoli) to fill the chest cavity with functioning lung. The procedure increases surface area of healthy tissue to increase gas exchange. It also stretches the remaining tissue to restore support of the major airways, and it improves expiration mechanics. The procedure also cuts off blood circulation through the removed regions that had little effective gas exchange. This prevents CO 2  laden blood from mixing back into the left side of the heart and to the arteries. 
   While the LVRS procedure is ideal in many ways, it requires major chest intervention that requires cutting the chest plate or major spreading of ribs. Pain associated with this causes interruption of normal breathing and difficulty to revive the patient from forced ventilation to normal breathing after the procedure. The procedure presents with high mortality rates and long recovery times. 
   Another risk with LVRS is associated with cutting too much volume out. By cutting more than approximately one third of the expanded lung volume per side (one third of the chest cavity volume per side), the tissue may be over-stressed and rupture with expansion. These ruptures culminate as spontaneous pneumothorax events (leaks that vent vacuum holding the lung up to the chest wall and allow collapse of the lung). Also, adhesions between the lung and chest wall that occur naturally present stress points upon expansion that can cause ruptures. 
   Tension pneumothorax complications can also be caused by the surgery. This is a condition that causes central chest organs to shift. The imbalance of force in the chest after expanding highly elastic lung tissue pulls the mediastinal region of the central thorax sufficiently to actually shift large vessels and cause flow restrictions. This condition can be very serious and warrant further surgeries. 
   If lung volume reduction (“LVR”) could be accomplished less invasively, the complications and morbidity associated with the surgery could be nearly eliminated. In addition, the procedure would be open to many more patients who might not be able to or not desire to undergo a major thoracic surgical procedure. Current less invasive approaches to LVR have met with limited success, however. 
   Bronchoscopically-placed LVR devices have been described which may be implanted into the lungs to block airways in an attempt to create a volume reduction effect distal to the blocking device to emulate LVRS. For example, plug and one-way air directing devices are introduced to block an area of the lung to cause oxygen depletion distally to cause volume reduction through a process known as atelectasis. These devices may provide some relief to the patient by blocking preferential filling of damaged lung tissue. All of these devices are inserted through the working channel of a flexible bronchoscope and are placed only as far as the third to the fifth subdivision or segment of bronchi. 
   However, there are several problems with these earlier devices as they are currently used. Current blocking devices do not facilitate access to distal regions of the lung after deployment to allow for reoccurring interventions or treatments. 
   In addition, current bronchoscope working channels are typically 2.0 mm in diameter; the blocking and one—way valve devices must be expanded to seat in airways that are as large as 15 mm in diameter. Therefore, the expansion ratio for these devices needs to sometimes be as high as 750%. Covered devices that are stretched to this extent are typically not robust air leak seals. Current devices are made small enough to fit down the working channel of the bronchoscope so they can be pushed out to self deploy. The devices are typically made of Nitinol alloys with long elastic range that drives recovery to an expanded state. This also requires that the device be scaled down to such a small diameter profile that the self expansion forces are extremely low to anchor the device and the covering materials must be thin and therefore fragile. 
   Moreover, these devices block air from flowing in the major airways but are not effective if collateral flow paths exist. The collateral paths allow the distal region to fill and hyper-inflate. When collateral flow is not an issue, these devices block O 2  and CO 2  exchange, and yet the blood flow in the region still carries CO 2  laden blood through the lungs to mix with systemic blood flow. Finally, uncontrolled atelectasis beyond a one third volume reduction may cause tension pneumothorax complications and stress ruptures within the lung wall, causing lung collapse. 
   SUMMARY OF THE INVENTION 
   The invention provides methods of performing lung volume reduction to treat a patient. One aspect of the invention provides a method of compressing a first portion of a lung of a patient including the following steps: providing a vent connecting the first portion of the lung to the exterior of the patient; isolating the first portion of the lung from a second portion of the lung adjacent the first portion; and delivering pressurized fluid to the second portion of the lung to compress the first portion of the lung. In some embodiments, the isolating step includes the step of delivering an expandable device to an air passageway communicating with and proximal to the first portion of the lung, with the step of providing a vent in some cases including the step venting the expandable device. In some embodiments, the isolating step includes the step of delivering a plurality of expandable devices to air passageways communicating with and proximal to the first portion of the lung. 
   In some embodiments of the invention, the step of delivering pressurized fluid includes the step of delivering pressurized fluid at a pressure of at least 10 mm Hg, 25 mm Hg, 45 mm Hg, or 55 mm Hg above atmospheric pressure. Some embodiments include the step of permitting fluid to enter the first lung portion when a difference between fluid pressure within the first lung portion and fluid pressure in the second lung portion exceeds about 2 mm Hg, about 10 mm Hg, about 20 mm Hg or about 50 mm Hg. 
   Another aspect of the invention provides a method of collapsing a portion of a lung of a patient including the following steps: inserting a catheter into the lung portion; and venting the lung portion through the catheter to the exterior of the patient without aspiration. 
   INCORPORATION BY REFERENCE 
   All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which: 
       FIG. 1  is a perspective view of an intra-bronchial device and delivery system according to one embodiment disposed within a patient&#39;s lung. 
       FIG. 2  is a detail view of an intra-bronchial device and delivery system according to another embodiment of the invention. 
       FIG. 3  is a cross-sectional view of an intra-bronchial device and deployment system according to yet another embodiment of the invention. 
       FIG. 4  is a cross-sectional view of an intra-bronchial device and deployment system according to still another embodiment of the invention. 
       FIG. 5  is a cross-sectional view of an intra-bronchial device and deployment system according to yet another embodiment of the invention. 
       FIG. 6  shows the use of an intra-bronchial device to treat a patient. 
       FIG. 7  shows yet another intra-bronchial device implanted in a patient&#39;s lung. 
       FIG. 8  shows an agent dispensing mechanism for possible use with this invention. 
       FIG. 9  shows a plug and delivery mechanism for use with an intra-bronchial device. 
       FIG. 10  is partial cross-sectional view of a plug and delivery mechanism for use with an intra-bronchial device. 
       FIG. 11  is a cross-sectional view of the intra-bronchial device of  FIG. 10  showing the plug in place. 
       FIG. 12  is a cross-sectional view of another embodiment of an intra-bronchial device and delivery mechanism with a plug in place. 
       FIG. 13  is a cross-sectional view of yet embodiment of an intra-bronchial device and delivery mechanism. 
       FIG. 14  is a cross-sectional view of still embodiment of an intra-bronchial device and delivery mechanism with a tool passing through the device&#39;s plug. 
       FIG. 15  is a schematic view of the plug of the device of  FIG. 14  in a closed position. 
       FIG. 16  is a schematic view of the plug of the device of  FIG. 14  in an open position. 
       FIG. 17  shows another embodiment of an intra-bronchial device opening mechanism in a closed position. 
       FIG. 18  shows the embodiment of  FIG. 17  in an open position. 
       FIG. 19  is an elevational view another embodiment of an intra-bronchial device opening mechanism. 
       FIG. 20  is an elevational view of a ring for use with the mechanism of  FIG. 19 . 
       FIG. 21  is a perspective view of a blade for use with the mechanism of  FIG. 19 . 
       FIG. 22  is an elevational view of an actuating ring for use with the mechanism of  FIG. 19 . 
       FIG. 23  shows the mechanism of  FIG. 19 , partially assembled. 
       FIG. 24  is a partial perspective and partial cross-sectional view of yet another embodiment of an intra-bronchial device and deployment mechanism. 
       FIG. 25  is a cross-sectional view of the embodiment of  FIG. 25  being expanded by the deployment mechanism. 
       FIG. 26  is a perspective view of the intra-bronchial device of  FIG. 24  and a deflation mechanism. 
       FIG. 27  is a cross-sectional view of the intra-bronchial device and deflation mechanism of  FIG. 26 . 
       FIG. 28  is a perspective view of a plug for use with the intra-bronchial device of  FIG. 24 . 
       FIG. 29  shows the plug of  FIG. 28  in place within an intra-bronchial device. 
       FIG. 30  shows the use of a plurality of intra-bronchial devices to treat a patient&#39;s lung. 
       FIG. 31  is a cross-sectional view of a pressure relief system for use with the invention. 
       FIG. 32  shows the pressure relief system of  FIG. 31  in an open position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The following tools may be used to treat COPD patients in a minimally invasive manner: Imaging and embolic devices to block blood flow through the target lung tissue; devices to help prepare the lung for devices and agents; a side wire delivery system that is advanced alongside the bronchoscope to guide and release several implants without removing the scope; a lung volume reduction implant device (Intra-Bronchial Device or IBD) that is controllably coupled to a delivery catheter that includes a working channel that runs through the center of the catheter and the implant; an inflator catheter that fits down the middle of the IBD and delivery catheter to inflate the IBD; an IBD plug element and delivery system; a deflation device to reposition or remove the IBD; a collateral flow detecting device; collateral flow blocking agents; adhesion promoting agents to maintain atelectasis; and a lung tissue compressing system. These items provide a reliable minimally invasive procedure for COPD patients and enable follow-on procedures to maintain a high degree of restored lung mechanics and gas exchange without causing tissue stress or blood chemistry complications that occur with current technology. 
   Perfusion of air flow in the lungs can be imaged using MRI imaging equipment while the patient breathes water saturated air or agents that are comprised primarily of water. Moving water molecules produce a strong signal, whereas static air and water will not produce a signal. This distinction is important to determine where the degraded lung hole regions reside. Hyper-polarized gases such as helium, helium-3 and xenon-129 also work extremely well in the lung to find damaged tissue and identify collateral flow. Computed tomography has also worked very well to identify damaged tissue in lungs. These imaging modalities can be used in real time before, after or during the procedure to check the patient&#39;s condition. They can also be used to guide intervention in an iterative fashion between imaging sessions or in real time. Ventilation Scans via SPECT (Xe-133) may also be used. 
   Specially-designed catheters can introduce lavage agents to the lung to wash mucus and surfactants. Mucus and naturally occurring surfactants trap solids and agents to block collateral flow paths and promote adhesions within the targeted lung region or portion. Cleaning these regions to remove fluids, mucus and surfactants improves distribution of these agents and enhances adhesion of glue compositions that may be infused into the region. 
   Fluoroscopic x-ray imaging is very useful to determine where blood flows through COPD damaged lung tissue. By introducing radiopaque high contrast materials into the blood stream, and with the use of digital subtraction techniques, the flow paths can be imaged very clearly. Embolic devices and agents that are used to treat peripheral vasculature may be utilized to embolize the pulmonary veins and arteries that normally exchange gases through the regions of the lung that are going to be or have been blocked and treated by the devices and agents of this invention. Exemplary embolic devices include embolic polymeric implants such as Dacron fibers, metallic coils, alcohols, glutaraldehyde, gels, foams, and glue such as cyanoacrylates, PEG based glues and glutaraldehyde based glues. 
   Embolizing this pulmonary vasculature will reduce or prevent CO 2  mixing into the heart. Pressure probes such as piezo, thermal transfer flow wires or micro-electrical-mechanical system (MEMS) wave interference pressure and flow transducers may be introduced or implanted to monitor pulmonary hypertension as the blood flow paths are being blocked and to monitor results over a period of time. That way the procedure can be limited to prevent undue blood back pressure on the heart. The lung tissue in the region will still be supplied with oxygenated blood from a separate artery system that feeds pulmonary tissue. Implantable MEMS devices can be used to measure pressure, temperature, strain and stress on tissues that are affected by the lung volume reduction procedure. MEMS transducers are passive (no electronics or batteries on board) implantable devices that can be queried using magnetic wave transmitter/receiver probes outside the body. 
   The design of the current invention resolves most of the deficiencies and issues related to the devices described above. The intra-bronchial device is placed in segments of bronchi that feed the diseased areas of the lung. As many as five to ten intra-bronchial devices could be placed in the bronchi of any one patient. The goal is to cause atelectasis in these areas and cumulatively expand the healthy portions of the lung, thereby replicating the results and benefits of LVRS, but without the morbidity and mortality. 
     FIG. 1  shows an intra-bronchial device  10  according to one embodiment of this invention disposed within a bronchial tube  12  of a patient&#39;s lung. Device  10  is in contact with the inner wall of bronchial tube  12  and is preferably immobilized through a friction fit. In this embodiment, device  10  includes an expandable balloon  14  with a central lumen  16  through which other devices or tools (such as guidewire  18 , as shown) may be passed. Device  10  may be delivered and deployed via a catheter  20  disposed within a working channel of a bronchoscope  22 . 
     FIG. 2  shows details of another embodiment of the invention. Device  23  may be delivered and deployed via a catheter  20  disposed within a working channel of a bronchoscope  22 . Delivery catheter  20  is connected to an inflatable balloon  25  of device  23  via a coupler  24  that may be connected and disconnected as desired. In this embodiment, catheter  20  has a braided shaft, and balloon  25  is a folded semi-elastic balloon made from polyethylene, polyvinyl, latex, etc. (Polyethylene is particularly preferable due to the its tissue ingrowth inhibition properties.) Balloon  25  may also be a uniform elastic balloon made from, e.g., silicone or polyurethane. The device has a ring  26  (made, e.g., from nitinol, stainless steel, polymer, Teflon, ceramic, composites, high density polyethylene, low density polyethylene, nylon, polyurethane) at its distal end marking the outlet of the balloon&#39;s central lumen. Catheter  20  may be used to deliver the device to a target site within the patient&#39;s bronchial tube  12  and/or to inflate balloon  25  once at the target site. 
     FIG. 3  shows one embodiment of a balloon deployment mechanism. In this embodiment, catheter  28  is coupled to balloon  30  via a threaded coupler  32  cooperating with internal threads  34  within the central lumen  36  of balloon  30 . Once in place at the target site, a fluid (such as a hydrogel, silicone, water, saline solution, air, glue, multipart catalytic solutions, fluidized metal, suspended metal, fluoroscopic contrast medium, sodium HA) can be injected through catheter  28  into lumen  36 . A seal  38  at the distal end of coupler  32  prevents the injection fluid from passing through the distal end of balloon lumen  36 . Instead, the fluid passes through one or more ports  40  in the wall of lumen  36  into balloon  30  to inflate the balloon. A one way flap  42  prevents the fluid from passing back into lumen  36  once the injection fluid pressure source is removed. After inflation of the balloon, catheter  28  may be rotated to disengage coupler  32  and to remove coupler  32  and seal  38  from the balloon. As shown in  FIG. 3 , the target site for the balloon is a bronchial wall site between adjacent cartilage areas  44  and  46 , enabling the inflation of balloon  30  to distend the bronchial wall to enhance the balloon&#39;s grip on the wall. 
     FIG. 4  shows an alternative balloon deployment mechanism. In this embodiment, a catheter  50  is coupled to balloon  52  via a threaded coupler  54  cooperating with internal threads within the central lumen  56  of the balloon. A filler tube  58  extends through catheter  50  into lumen  56  and through a port  58  formed in the lumen wall to push open a flap  60  to communicate filler tube  58  with the inside of balloon  52 . Filler tube  58  may be used to inflate the balloon with an injection fluid, such as one of the fluids listed above. Filler tube  58  may also be used to remove fluid from the balloon to deflate the balloon for removal or repositioning of the balloon. After inflation of the balloon, catheter  50  may be rotated to disengage coupler  54  from balloon  52 . 
     FIG. 5  shows yet another embodiment of the invention. In this embodiment, balloon  70  is inflated so that it does not substantially distend the bronchial tube walls. Balloon  70  is also longer than the balloons of the previous embodiments, extending, e.g., beyond adjacent cartilage sections of the bronchial tube wall. The balloon&#39;s configuration allows it to distort as the bronchial expands and contracts during the patient&#39;s breathing cycle. 
   Balloon  70  may be inflated using, e.g., the balloon deployment mechanisms described above with respect to  FIGS. 3 and 4 . A port  72  communicates the device&#39;s inner lumen  73  with the inside of the balloon through a flap  74 , as described above. 
     FIG. 5  also shows yet another mechanism for releasably coupling a catheter to the device. Catheter  76  has a split distal end  78  with an annular engagement structure  80  configured to engage with an annular channel  82  formed on the proximal end of the device. A coupler sleeve  84  surrounding catheter  76  may be retracted proximally to permit the split distal end  78  to expand outwardly, thereby disengaging the device, and may be advanced distally to pull distal end  78  radially inward to engage the device. 
     FIG. 6  shows the use of an intra-bronchial device to treat a patient. An expandable intra-bronchial device  100  (such as one of the balloon devices described above) has been deployed at a target site in a patient&#39;s bronchial tube  102  via, e.g., a delivery catheter  104 . A second catheter  106  has been passed through catheter  104  and the central lumen of device  100  to a treatment site  108  further down into the patient&#39;s lung. The distal end  110  of catheter  106  may be lodged in the patient&#39;s bronchial at the treatment site. Catheter  106  may then be used to induce atelectasis via, e.g., suction, vacuum, lavage with an anti-surfactant agent, mechanical compression, sclerosing agents (such as alcohol or other fluids or aerosols), etc. 
     FIG. 7  shows the use of an intra-bronchial device to treat a patient in another manner. An expandable intra-bronchial device  120  (such as one of the balloon devices described above) has been deployed at a target site in a patient&#39;s bronchial tube  122 . A plurality of wires  124  are delivered through the central lumen of device  120  to place the wires&#39; distal ends  126  within a lobe or section  128  of the patient&#39;s lung. The wire ends are glued or anchored to the tissue within lobe  128 . The proximal ends of wires  124  have one-way locks  130  that may be pulled proximally through the device&#39;s  120  central lumen after anchoring of the distal ends to collapse lobe  128  inwardly. Locks  130  hold wires  124  in position, as shown. 
     FIG. 8  shows an agent-dispensing mechanism for possible use with this invention. A delivery catheter  131  is mounted on a guidewire  132  via a sideport  133 . Agents such as glue or other substances may be delivered from syringe  134  via catheter  131  through an intra-bronchial device to the lung region distal to the intra-bronchial device. (The length of catheter  131  is shortened in  FIG. 8  for illustration purposes. The catheter must be long enough for the syringe to be outside the patient&#39;s body and the distal end of the syringe extending into and through the intra-bronchial device.) 
   After treatment of lung tissue distal to an intra-bronchial device, the device&#39;s central lumen may be closed. The device&#39;s central lumen may thereafter be opened should access to lung tissue distal to the device be desired.  FIG. 9  shows one embodiment of an intra-bronchial device plug  140  for deployment via catheter  142  to seal device  144  (such as one of the balloon devices described above). A tether  146  may be used to disengage plug  140  after deployment in device  144 . 
     FIGS. 10 and 11  show another embodiment of an intra-bronchial device plug  150  being delivered to device  152  (such as one of the balloon devices described above) via delivery catheter  154 . Plug  150  is releasably held to a plug pusher or catheter  156  by a tether  158 . Plug  150  has threads  160  that engage with threads  162  in device  152  when plug  150  is rotated by catheter  156  to seal the central lumen of device  152 . 
     FIG. 12  shows yet another embodiment of a plug  170  for an intra-bronchial device  172  (such as the balloon device described above with respect to  FIG. 5 ). Plug  170  has a stem  174  (formed, e.g., from metal or plastic) passing through an occlusion element  176  formed from an elastomeric polymer or gel. Plug  170  may be advanced into position by compressing it through a narrowed proximal end  182  of the central lumen  184  of device  172  through the action of a pusher or catheter (not shown) coupled to a coupling surface  180  formed on the proximal end of stem  174 . To reopen the central lumen  184  of device  172 , plug  170  may be advanced distally or retracted proximally. 
   In alternative embodiments, the plug may attach to the device using notches, luer locks, press fit, tapers, etc. 
     FIG. 13  shows yet another plug  200  for an intra-bronchial device  202 . In this embodiment, plug  200  forms an elastomeric seal around a central opening  204  through which tools or other devices may be inserted. Plug  200  may be integral with device  202  so that it does not have to be delivered separately from device  202 . 
     FIGS. 14-16  show an intra-bronchial device  210  with an integral seal  212  having a central opening  213  formed by the cooperation of a plurality of flaps  216 . Seal  212  may be integral with the central tube  214  of device  210 . Central tube  214  and seal  212  may be formed from an elastic metal or polymer or rubber to allow flaps  216  to bend (as shown in  FIG. 16 ) to permit devices or tools to be passed through opening  213 . Flaps  216  return to their sealing position of  FIG. 15  after the tool or device (such as guide wire  215 ) has been removed. 
     FIGS. 11-14  show plugged intra-bronchial devices attached to their respective catheters using releasable coupling mechanisms such as those described above with respect to  FIG. 5 . The coupling mechanisms help hold the device in place at the target site while the plug is being inserted. 
   It may also be necessary after deployment of an intra-bronchial device to deflate the balloon and remove the device from the patient. In addition to the deflation method described above with respect to  FIG. 4 , deflation may be accomplished by, e.g., puncturing the balloon. Once the balloon is deflated, the device may be coupled to a catheter as shown in  FIGS. 11-14  and removed from the patient and/or deployed at a different site. 
     FIGS. 17-23  show alternative designs for intra-bronchial device openings formed, e.g., as actuatable iris-type shutters. As shown in detail in the alternative embodiment of  FIGS. 19-23 , the shutter is formed from a plurality of blades  220  rotatably mounted on a ring  222  via pins  224  inserted into holes  226  formed in the ring. The blades are arranged in an overlapping arrangement as shown in  FIG. 19 . The shutter is operated by an actuating ring  228  having slots  230  interacting with a second set of pins  232  on blades  220 . Rotation of ring  228  in one direction opens the shutter, and rotation of ring  228  in the other direction closes the shutter.  FIGS. 17 and 18  show a five-blade shutter design, while  FIGS. 19-23  show an eight-blade shutter design. 
     FIGS. 24-29  show another embodiment of the invention (outside of the lung, for ease of illustration). Intra-bronchial device  250  has a central shaft  252  surrounded by an expandable member, such as balloon  254 . Shaft  252  has an opening  256  communicating the shaft&#39;s central lumen with the interior of balloon  254  via a flexible flap valve  258 . Device  250  may be delivered to an air passageway of a patient&#39;s lung using a delivery catheter in, e.g., a manner described above. 
   An inflation catheter  260  may be used to inflate balloon  254  from the unexpanded condition shown in  FIG. 24  to the expanded state of  FIG. 25 . Inflation catheter  260  may be inserted into the patient through the delivery catheter (delivered together with the device  250  or after it) or independent of the delivery catheter. The distal tip  262  of inflation catheter  260  has a pointed end to help align the inflation catheter with the intra-bronchial device&#39;s shaft. Inflation catheter  260  has an opening  264  with seals  266  and  268  on either side. When inserted into shaft  252 , opening  264  aligns with the shaft&#39;s opening  256  when a shoulder  270  on inflation catheter  260  meets a shoulder  272  formed on the proximal end of device  250 . Seals  266  and  268  ensure that pressurized fluid delivered to device  250  via inflation catheter  260  enters balloon  254  via openings  264  and  256  and flap valve  258  to inflate balloon  254 . When the inflation pressure ceases, flap valve  258  closes to maintain balloon  254  in its inflated state. The device  250  may be inflated in multiple steps, as needed. 
   The inflation catheter may protrude through the distal end of the intra-bronchial device. By extending the inflation catheter tip length, we can provide a path to thread a delivery wire through the distal tip and out a side port to make the intra-bronchial device, intra-bronchial device delivery catheter and inflation catheter a rapid exchange system. Rapid exchange systems are catheter systems that can be threaded onto a short section of wire before the user can gain control of the wire end and the catheter system. By installing a catheter that does not provide a side port onto a wire, the user must advance the entire length of the catheter onto the wire before the user gains control of the end of the wire again. By providing a side port to any of the catheter devices required in the lung volume reduction kit, we enable the use of wires that are only long enough to extend outside the scope or patient and that provide for some extra length to be threaded into one or more devices and out the side port. Alternatively, the wire may be introduced into and out of a side port or it can be introduced in any combination of side, end or through lumen compartments. 
     FIGS. 26 and 27  show a deflation catheter  280  that may be used to deflate intra-bronchial device for removal or repositioning. Deflation catheter may be advanced through the device delivery catheter or independently. Deflation catheter has a plurality of fingers  282  separated by slots  283  and arranged circumferentially around the catheter&#39;s distal end. When advanced into shaft  252 , shoulders  284  formed on the distal ends of fingers  282  cam radially inward to enable the catheter  280  to be advanced into device  250 . When one or more shoulders  284  line up with opening  256  of device  250 , their respective fingers move radially outward, displacing flap valve  258  away from opening  256  and permitting the balloon&#39;s inflation fluid to escape into catheter  280 , thereby deflating balloon  254 . A shoulder  286  meets shoulder  272  of device  250  when fingers  284  have been advanced distally to the proper position with respect to opening  256 . 
     FIGS. 28 and 29  show a plug  300  for an intra-bronchial device, such as the device described in  FIGS. 24 and 25 . For illustration,  FIG. 29  shows balloon  254  in a deflated state. A plurality of fingers  302  separated by slots  304  are disposed at the distal end of plug  300 . The distal end of each finger  302  has an angled camming surface  306  facing distally and a steeper camming surface  308  facing proximally. The plug has a radially symmetric coupling handle  310  at its proximal end for attachment to a delivery and/or recapture catheter (not shown). When inserting plug  300  into the intra-bronchial device, distal movement of plug  300  into shaft  252  causes fingers  302  to cam radially inward until the distal end of plug  300  emerges from the distal end of shaft  252 , at which point fingers  302  move outward to lock plug  300  in place. A proximal shoulder (not shown) may be provided on plug  300  to prevent the plug from advancing out the distal end of the intra-bronchial device. If removal of plug  300  is desired, a proximally directed force on plug  300  will cause fingers  302  to cam inward to allow the plug to be withdrawn through shaft  252 . 
     FIG. 30  shows the use of the invention to compress a portion of a patient&#39;s lung. In this example, three intra-bronchial devices  150   a ,  150   b  and  150   c  are disposed in a portion  320  of the patient&#39;s lung. Devices  150   a  and  150   b  have been plugged and released from their delivery systems; device  150   c  is still connected to catheter  322  which communicates with the still-open lumen  324  of the device&#39;s central shaft. To compress lung portion  320 , pressurized fluid is introduced into the patient&#39;s lung through sleeve  326  surrounding catheter  322 . An expandable (e.g., inflatable, expanding metallic frame or braid) cuff  328  seals sleeve against the air passageway wall. Devices  150   a - c  prevent the pressurized fluid from entering lung portion  320 . Inflation of one or more portions of the lung adjacent portion  320  will cause portion  320  to collapse, venting any air in lung portion  320  to the exterior of the patient through catheter  322 . These devices cause effective lung tissue compression with the application of more than 10 mm Hg pressure above atmospheric pressure. By applying more pressure, the effect is made more rapid and complete: 25 mm Hg is better, 45 mm Hg is better still and more than 55 mm Hg is best. 
   The sleeve can be made of typical guide catheter materials with similar construction techniques and may be covered or comprised of silicone, polyurethane, biocompatible polymers, elastic balloon materials, semi-elastic balloon materials or a mesh composite. The balloon can be compliant or semi-compliant and can be made from polymers such as polyurethane or silicones. The cuff may be self expanding with the use of titanium alloys and these can be made from braid. Braided funnel shaped ends work very well to seal this device. 
   It is also possible to cause the target portion of the lung to collapse naturally, without hyperinflation of other portions of the lung. Once a lung region has been isolated, oxygen is absorbed from the air in a greater volume than CO 2  is deposited. This absorptive atelectasis or auto-atelectasis causes the isolated lung region to collapse, allowing remaining portions of the lung to expand into that space. 
   Over-expansion of the remaining portions of a lung after collapse of one portion of the lung can cause tissue tears and other injuries.  FIGS. 31 and 32  illustrate a pressure relief system that minimizes the risk of such injuries. Intra-bronchial device  350  has a pressure relief valve  352  that opens (as shown in  FIG. 32 ) when the differential pressure between the collapsing lung portion on the distal side of device  350  and the lung portions on the proximal side of device  350  exceeds a desired amount, such as, e.g., 2 mm Hg, 10 mm Hg, 20 mm Hg or 50 mm Hg. The greater the differential pressure, the greater the lung volume reduction, but also the greater the risk of complications. Alternatively, a maximum lung expansion may be targeted. For example, the pressure required to open the relief valve can be set such that the expanding lung tissue is not strained more than 150%. The pressure relief valve may also reside in an intra-bronchial device plug instead of being integral with the expandable intra-bronchial device itself. 
     FIG. 30  also shows aspects of a collateral flow detection system for use with this invention. Prior to attempting hyperinflation of the lung to collapse the target portion of the lung, this system can be used to check for the existence of collateral flow paths from the targeted lung portion  320  back to the remaining portions of the lung and the exterior of the patient. Air blended with a marker such as a detectable gas may be introduced into the lung through sleeve  326 , and the air in the target region  320  may be monitored through catheter  322  by sniffing or sampling. If the marker gas is detected, collateral flow is occurring, either due to the presence of flow paths through degraded tissue, natural airways that still need to be plugged with intra-bronchial devices, or the failure of one or more implanted intra-bronchial devices. Gases that may be used for collateral flow detection are hyper-polarized gases such as helium, helium-3 and xenon-129. Other materials include Diethyl ether, Nitrous oxide, Chloroform, Cyclopropane, Trichloroethylene, Fluroxene, Halothane, Methoxyflurane, Enflurane, Isoflurane, Desflurane, Sevoflurane or components of these. Small amounts of CO can also be tolerated and used for this purpose. 
   Upon detection of collateral flow paths, one or more agents to block and clog the collateral flow paths may be introduced, e.g., through the intra-bronchial device delivery catheter so that it is installed in the isolated lung region. The agent will flow through any such collateral flow path. This treatment is intended to block flow of collateral pathways that are created by the degenerative disease. As such, treatments may need to be repeated periodically to block pathways that are newly formed by the disease progression. This can be easily done by coupling a delivery catheter to the intra-bronchial device and then by removing the central cap from the intra-bronchial device. This provides a direct conduit to the distal isolated lung region. 
   Microparticles can be used for blocking collateral flow in lung tissue. The microparticles preferably comprise a polymeric binder or other means to make controlled geometry particles. Suitable polymeric binder materials include poly(glycolic acid), poly-d,l-lactic acid, poly-l-lactic acid, copolymers of the foregoing, poly(aliphatic carboxylic acids), copolyoxalates, polycaprolactone, polydioxanone, poly(ortho carbonates), poly(acetals), poly(lactic acid-caprolactone), polyorthoester, poly(glycolic acid-caprolactone), polyanhydrides, polyphosphazines, albumin, casein, and waxes. Poly (d,l-lactic-co-glycolic acid) is commercially available from Alkermes, Inc. (Blue Ash, Ohio). A suitable product commercially available from Alkermes, Inc. is a 50:50 poly (d,l-lactic-co-glycolic acid) known as MEDISORB.RTM. 5050 DL. This product has a mole percent composition of 50% lactide and 50% glycolide. Other suitable commercially available products are MEDISORB.RTM. 6535 DL, 7525 DL, 8515 DL and poly(d,l-lactic acid) (100 DL). Poly(lactide-co-glycolides) are also commercially available from Boehringer Ingelheim (Germany) under its Resomer.RTM. mark, e.g., PLGA 50:50 (Resomer.RTM. RG 502), PLGA 75:25 (Resomer.RTM. RG 752) and d,l-PLA (Resomer.RTM. RG 206), and from Birmingham Polymers (Birmingham, Ala.). These copolymers are available in a wide range of molecular weights and ratios of lactic acid to glycolic acid. 
   Other materials include biocompatible polymers that are described in the US Pharmacopeia and include dextrans and other carbohydrate-based materials or derivatives thereof, polyethylene glycol, polyethylene oxide, polyvinyl alcohol, and starch. Additional materials include polyesters, such as polyglycolic acid, polylactic acid, poly-1,4-dioxa-2-one, polyoxaltes, polycarbonates, copolymers of polyglycolic acid and polylactic acid, polycaprolactone, poly-b-hydroxybutyrate, copolymers of epsilon-caprolactone and delta-valerolactone, copolymers of epsilon-caprolactone and DL-dilactide, and polyester hydrogels; polyvinylpyrrolidone; polyamides; gelatin; albumin; proteins; collagen; poly(orthoesters); poly(anhydrides); poly(alkyl-2-cyanoacrylates); poly(dihydropyrans); poly(acetals); poly(phosphazenes); poly(urethanes); poly(dioxinones); cellulose; agarose, agar, and starches, and derivatives of any of the aforementioned. 
   Block copolymers are another class of materials that are suitable for the present invention. 
   Protein microspheres are another class of materials that enables the present invention. For example, albumin can be cross-linked with a suitable cross-linker to generate particles for various applications including imaging. Other proteins suitable for enabling the present invention include recombinant or naturally occurring human, animal, or vegetable proteins, including collagen, gelatin, casein, soybean protein, vegetable protein, and keratin. 
   Liposomes, proliposomes, or microparticles containing fatty acids, lipids, or derivatives thereof will also enable the invention. 
   Synthetic polymeric particles comprised of HEMA (hydroxyethlymethacrylate), AEMA (aminoethyl methacrylate), DMEMA (N,N dimethyl amino) and other acrylates, acrylamides, methacrylamides, styrene, or any polymerizable material will also work in this application. 
   A viscous solution that reduces or blocks collateral flow in lungs may also be used. Viscous solutions for the present invention are preferably biocompatible solutions such as hydrogels or other substances including glycerol and aqueous solutions containing water soluble materials including cellulose derivatives, dextrans, starches, and any carbohydrate or carbohydrate based material or derivative thereof. Other aqueous solutions may contain synthetic polymers including povidone, PEG (polyethylene glycol or polyethylene oxide), polyvinyl alcohol, and diethyl aminoethyl (DEAE)—sephadex. Aqueous solutions may also contain proteins such as collagen and albumin. Other viscous solutions may contain non-aqueous cosolvents such as ethanol. Buffers, salts, and excipients may also be part of the formulation of thixotropic viscous solutions. 
   In one embodiment, a two-part sealant may be applied to areas of interest. One novel method involves applying one part of the sealant to a desired area in one lobe, and applying a second component to the other lobe. The two components may mix and solidify at a location between the lobes, or partially in both lobes such that flow is reduced. Sealant components for this application may include fibrin/thrombin, activated PEG/PEG-diamine, albumin/PEG, and albumin/glutaraldehyde sealants. The sealant is an implantable material that may contain hemostatic agents such as chitin derivatives including but not limited to carboxymethyl chitin and chitosan (1-100% deacetylated). The sealant components may also contain additives that affect viscosity, set time, adhesion, and biocompativility. The albumin component may be formulated in weight to weight ratios of 10-50% where the remaining mass balance is aqueous solutions of salts, buffers, and additives or combinations thereof. The other component of the sealant is a cross-linker containing glutaraldehyde or derivatives thereof in weight to volume ratios of 1-25% where the remaining balance is an aqueous solution with or without additives, salts, or buffers or combinations thereof. These solutions may be applied from dispensers that deliver a ratio of 1 unit volume of protein solution per 1 unit volume of cross-linker solution (1:1 protein:cross-linker) and may be applied in ratios up to 10 unit volumes of protein solution per unit volume of cross-linker solution. Furthermore, mixing may occur by passing the solutions through a static mixing tip with helical or other geometrical devices that enhance the mixing efficiency. Sealants prepared from these solutions contain 5-45% protein and 0.5-14% crosslinker. 
   Other suitable sealants and other agents are described in U.S. Pat. Appl. Publ. No. 2004/0052850; U.S. Pat. Appl. Publ. No. 2004/0081676; U.S. Ser. No. 11/008,577; U.S. Ser. No. 11/008,092; U.S. Ser. No. 11/008,094; U.S. Ser. No. 11/008,578; U.S. Ser. No. 11/008,649; U.S. Ser. No. 11/008,777; U.S. Ser. No. 11/008,087; U.S. Ser. No. 11/008,093; U.S. Ser. No. 11/008,580; and U.S. Ser. No. 11/008,782. 
   We have determined that many of these agents cause tissue binding to form localized adhesions or a bio-response that will help maintain a permanent volume reduction. With the introduction of these materials we are instigating one or more elements of a well understood tissue remodeling cascade process. The process includes tissue polymer decomposition and/or necrosis that leads to recruitment of cellular respondents that include one or more of the following: Neutrophils, white blood cells, macrophages, CD8+, MMP&#39;s, Interlukens, cytokins and protocylins. Then the tissue remodels to initiate tissue formation and thickening that culminates in the formation of tissue adhesions. 
   Other materials that can initiate this effect are cadmium, smoke artifacts, tars, materials that irritate tissue such as alcohols, solvents, organic solvents, acids, materials that are basic and materials that are acidic. These include compounds or materials that have pH levels between 1 and 6.9 with materials closest to 1 being a preferable acid material. Additionally, compounds or materials that have pH levels between 7.5 and 14 work very well but materials closest to 14 work best. 
   Materials that solidify such as glue compositions form a structure that is typically stiffer than the intrinsic stiffness of lung tissue. Specifically, pull tests of lung parenchema (comprised of alveoler sacks and collagen) sections show that the composite stiffness is very low. When we combine agents that form a stiffer structure than the underlying biomaterial or lung tissue, the modulus mismatch causes irritation, inflammation, tissue thickening, fibrosis, a remodeling cascade and adhesions that will promote and maintain lung volume reduction. Compositions that dry out or maintain viscosity levels above 2 centipoise (a measure of dynamic viscosity) generate shear and cause this stiffness mismatch to promote adhesions. Agents and hydrogel materials thicker than 10 centipoise work better. Our glutaraldehyde glue technology can produce compositions that have 15 centipoise viscosity and higher levels up to and beyond 150 centipoise. By increasing the glue cross linking properties, we can deliver agents that solidify to a gel or harder substance. Materials that gel to produce solids with a modulus greater than 10-20 centimeters of H 2 O will produce this same effect. Materials that are stiffer in a range between 20 and 100 centimeter of H 2 O are better. Materials that are stiffer than 100 cm H 2 O are preferable. We have developed several implantable materials with viscosity enhancing agents to promote these effects. 
   When applying an implantable hydrogel comprised of a biocompatible material, or an implantable liquid that undergoes a physical transition from a liquid to a gel or other solid such as solid adhesives, control of deposition is very important. Ways of controlling deposition include localized dispensing of the sealant through a suitable device containing a lumen, and also through the addition of agents that increase the viscosity of one or more components of the implantable material. Such agents include biocompatible materials with viscosities that are greater than those of water, and include glycerol, polymeric materials such as proteins, carbohydrate-based polymers and derivatives thereof, synthetic materials including polyethylene glycols (PEG), polyethylene oxides (PEO), polyvinyl pyrrolidone (PVP), polyvinyl alcohol and other components described in the “United States Pharmacopeia” and Rowe, R. C, et al.,  Handbook of Pharmaceutical Excipients  4 th  edition 2003. Other materials for controlling viscosity include oils, lipids, and fatty acids, including oleic acid, and phosphocholines. Phase separation can be controlled with emulsifiers including poly sorbate. For sealants prepared by mixing two or more components, the viscosities of one or more of the components can be modified by adding an appropriate agent to control spreading after application. Viscosities of these components can range from 1 to 1000 centistokes (a measure of kinematic viscosity). 
   Deposition and control of spreading of sealants containing two or more components are also affected by the gel time, or set time, of the mixed sealant. Sealants with short set times are preferable to those with longer set times. Ideal set times for the present invention and method range from 1-600 seconds, and preferable from 1-60 seconds. Set time can be controlled by the addition of set time modifiers, including agents that reduce or increase the set time relative to the corresponding formulation lacking the set time modifier. An example of an agent that decreases the set time is carboxymethyl cellulose. An example of an agent that increases the set time is glycerol. 
   Glutaraldehyde, as currently processed and used in some commercial sealants, undergoes reversible reactions that cause reoccurring inflammation. These properties can be improved by chemical modification of the glutaraldehyde. One such modification includes glutaraldehyde condensation reactions, as described in “Bioconjugate Techniques” by G. T. Hermanson. This condensation involves the formation of derivatives of glutaraldehyde in aqueous solutions containing acid or base. This reaction can be monitored by ultraviolet spectroscopy at or near 280 and 234 nanometers. At 280 nanometers, pure glutaraldehyde has significant absorbance, and little or no absorbance at 234 nanometers when measured as an aqueous solution at 0.5% weight to volume. When glutaraldehyde is chemically modified, it has significant absorbance at 234 nanometers. These derivatives are effective cross-linking agents when used with nucleophilic substrates such as proteins, including albumins. Furthermore, sealants prepared from glutaralde hyde derivatives are adhesive in vivo, through chemical or mechanical means, or a combination of chemical and mechanical means. 
   Implantable materials for the present invention are any agents administered into tissue, including sealants, which may be comprised of hydrogels, proteins, or other biocompatible materials, that can be implanted into compromised tissue to benefit the patient. Examples of hydrogels include those prepared from natural sources including carbohydrate-based materials. Such materials include hyaluronans, hyaluronic acid, alginates, chitins, chitosans, and derivatives thereof. Proteins that enable the present invention include albumins, collagens, gelatins, and other proteins that can be cross-linked or that form solutions with viscosities greater than water. Other implantable materials include those prepared by mixing two or more components so that a viscous solution, gel, or solid is formed. Such implantable materials are prepared from a protein substrate where the protein is derived from natural, synthetic, or semi-synthetic processes. The protein may also be derived from recombinant DNA technology and may be isolated from cell-culture processes, as well as from transgenic plants and animals. Examples of proteins include albumins, collagens, and gelatins. Cross-linkers employed as part of the implantable material precursors include aldehydes, polyaldehydes, esters, and other chemical functionality suitable for cross-linking protein(s). Examples of homobifunctional cross-linking agents are described in “Bioconjugate Techniques” by G. T. Rermanson. 
   The implant components, including the cross-linking agent and the substrate, can be formulated at a pH in the range of 5-10 by adjusting the pH and/or by adding suitable buffers in the range of 1-500 mM. Examples of buffers include phosphate, carbonate, bicarbonate, borate, or imidazole, or mixtures thereof. Additionally, additives or stabilizers may be added to improve the stability of one or more of the components. Furthermore, imaging agents may be added to allow for detection of the material. Such agents include iodine, iodine compounds, metals such as gadolinium, radioisotopes, and other compounds for gamma scintigraphy, magnetic resonance imaging, fluoroscopy, CT, SPECT and other imaging modalities. Additionally, the material may be formulated such that the mechanical properties are suitable for applications in the specific tissue to which the imp lantable material is applied. Such properties include elasticity, modulus, stiffness, brittleness, strain, cohesion, adhesion, and stress. Agents for modifying the properties include fillers, plasticizers, and adhesion modifiers. Furthermore, the implant may induce a natural adhesive mechanism with or without the addition of chemical agents which may be added to the implant to induce a natural response. Such agents include particles in the range of 100 nm to 1 millimeter. Agents include chemical or biochemical agents (proteins or nucleic acids) that induce a natural response. Examples of such agents include bleomycin, cytokines and chemokines, and single stranded RNA molecules. 
   Intra-bronchial devices according to this invention may be delivered through the working channel of a bronchoscope. Alternatively, the lung access system described in the U.S. patent application filed of even date herewith titled “Lung Access Device and Method,” may be used to deliver the devices to a patient&#39;s lung. This latter delivery method may be used when the diameter of a bronchoscope is too small for the device to be delivered. One advantage of using an intra-bronchial device with a larger, collapsed delivery diameter is that the expansion ratio from delivery diameter to deployed diameter may be made smaller than, e.g., 7.5, more preferably smaller than 6, more preferably smaller than 5, more preferably smaller than 4, and most preferably smaller than 3. 
   Another advantage of using the alternative outside the scope delivery system is that the delivered devices are not limited in length since they can be delivered outside the constraints of the scope channel. The scope path to the upper airways, where the most tissue damage normally resides, requires very small radius bends to be formed in the bronchoscope to gain access. Long implant devices that would straighten the scope if delivered through the channel can now be delivered outside the channel while the target region continues to be imaged through the scope optics. 
   In addition, it is desirable to make the implant longer than its diameter to provide stability from, e.g., rotating in the airway. These relative dimensions also make it much easier to capture the end of the device later to access the through-lumen or to recover or move the device. Implant devices that exceed 4 mm in length can now be delivered easily using this system. Devices longer than 5 mm will work better, devices longer than 10 mm are better, devices longer than 20 mm are preferable, devices longer than 25 mm, 30 mm, and 35 mm will anchor much better. 
   These devices can be made from all biocompatible plastics, metals, ceramics, shape memory alloys and carbon based fiber or polymers. The catheter devices can be lined with fluoro polymers and reinforced with metal or polymer fiber or wire braid or by using coils of similar materials. The wire elements that guide devices can be made from steel or titanium alloys or other metals that do not present artifacts in MRI equipment. Other materials including shape memory alloys such as nickel- and titanium-based metals that are comprised of more than 40% titanium would perform well in that they can be made in an anisotropic way to provide different properties with bending and torque. 
   In some embodiments, one or more of the delivery and deployment catheters may have multiple lumens. For example, a multi-lumen catheter could be used to both inflate the intra-bronchial device and deliver glue or another substance (such as those described above) outside of, and either distal or proximal to, the intra-bronchial device. Sheaths, needles and other devices may be used to deploy such substances. 
   Another use of an extra-catheter lumen is as a return path. As long as the pressure drop over the return path is less than the pressure required to inflate the intra-bronchial device, air or the inflation fluid will preferentially flow down the return path. The pressure can be controlled with the delivery rate of the inflation fluid. This return path can also act as a pressure relief conduit to control the maximum inflation pressure applied to the balloon. 
   While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.