Abstract:
Devices systems and methods are disclosed for preventing or inhibiting secretions from entering the lumen of a functional assessment catheter for the lungs, or removing collected secretions. The catheter comprises an expandable element, a cover, or an internal component configured to prevent or inhibit secretion flow into the lumen. The catheter alternatively or additionally comprises a distal end configured to facilitate air flow, absorb secretions or repel secretions away from the catheter tip. The catheter alternatively or additionally comprises an internal element such as a coilable wire, or an obturator configured to prevent secretions from being drawn into the lumen, or to actively remove the secretions. The catheter alternatively or additionally comprises an element to dry, aerate or aspirate the lung passageways.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of International Patent Application No. PCT/US2009/056392 (Attorney Docket No. 017534-005010PC), filed Sep. 9, 2009, which claims priority to U.S. Provisional Application No. 61/095,582 (Attorney Docket No. 017534-005000US), filed Sep. 9, 2008, the full disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates generally to catheters and more specifically to catheter apparatus and approaches for minimizing entry of secretions into the catheter and more particularly in those catheters that are used for assessing pulmonary function. 
         [0004]    2. Description of the Related Art 
         [0005]    Chronic obstructive pulmonary disease is a significant medical problem affecting 16 million people or about 6% of the U.S. population. Specific diseases in this group include chronic bronchitis, asthmatic bronchitis, and emphysema. While a number of therapeutic interventions are used and have been proposed, none are completely effective, and chronic obstructive pulmonary disease remains the fourth most common cause of death in the United States. Thus, improved and alternative treatments and therapies would be of significant benefit. 
         [0006]    Of particular interest to the present invention, lung function in patients suffering from some forms of chronic obstructive pulmonary disease can be improved by reducing the effective lung volume, typically by resecting diseased portions of the lung. Resection of diseased portions of the lungs both promotes expansion of the non-diseased regions of the lung and decreases the portion of inhaled air which goes into the lungs but is unable to transfer oxygen to the blood. Lung volume reduction is conventionally performed in open chest or thoracoscopic procedures where the lung is resected, typically using stapling devices having integral cutting blades. 
         [0007]    While effective in many cases, conventional lung volume reduction surgery (LVRS) is significantly traumatic to the patient, even when thoracoscopic procedures are employed. Such procedures often result in the unintentional removal of healthy lung tissue, and frequently leave perforations or other discontinuities in the lung which result in air leakage from the remaining lung. Even technically successful procedures can cause respiratory failure, pneumonia, and death. In addition, many older or compromised patients are not able to be candidates for these procedures. 
         [0008]    As an alternative to LVRS, endobronchial lung volume reduction (ELVR) uses endobronchially introduced devices which plug or otherwise isolate a diseased compartment from healthier regions of the lung in order to achieve volume reduction of the diseased compartment. Isolation devices may be implanted in the main airways feeding the diseased region of the lung, and volume reduction takes place via absorption atelectasis after implantation or via collapse by actively suctioning of the target compartment prior to implantation. These implanted isolation devices can be, for example, self-expanding occlusive stents that prevent air flow in both directions or one-way valves that allow flow in the exhalation direction only. 
         [0009]    While a significant improvement over LVRS, ELVR can have a limited therapeutic benefit when the treated region in the lung is exposed to collateral ventilation from adjacent regions. The lungs comprise a plurality of compartments, referred to as lung compartments or lobes, which are separated from one another by a double layer of enfolded reflections of visceral pleura, referred to as fissures. While the fissures which separate the compartments are typically impermeable, in patients suffering from COPD, the fissures are frequently incomplete, leaving a pathway for collateral airflow or inter-lobular collateral ventilation. Such collateral airflow can result in the intrusion of air into the isolated lung compartments treated by ELVR, thus reducing or eliminating the desired volume reduction. 
         [0010]    Collateral flow to diseased lung compartments can be detected, for example using the methods described in co-pending, commonly-owned U.S. patent application Ser. No. 11/296,591, filed on Dec. 7, 2005 (US 2006/0264772A1) and Ser. No. 11/550,660, filed on Oct. 18, 2006 (US 2007/0142742A1). 
         [0011]    The catheter comprises a catheter body, and an expandable occluding member on the catheter body. The catheter body usually has a distal end, a proximal end, and at least one lumen extending from a location at or near the distal end to a location at or near the proximal end. At least a distal portion of the catheter body is adapted to be advanced into and through the airways of a lung so that the distal end can reach an airway which feeds a target lung compartment or segment to be assessed. The expandable occluding member, such as an inflatable balloon, is disposed near the distal end of the catheter body and is adapted to be expanded in the airway which feeds the target lung compartment or segment so that said compartment or segment can be isolated with access provided only through the lumen or catheter body when the occluding member is expanded. Simultaneously, the expandable occluding member may add to catheter function by centering the distal end of the catheter within the airway. In this state, inhaled air is precluded from entering the catheter lumen, while exhaled air from the isolated lung compartment can exit only through the catheter lumen. 
         [0012]    The exhaled air exits the proximal end of the catheter lumen, which is coupled to an external console. The external console monitors the characteristics of the exhaled air, such as flow and pressure, and communicates the values associated with such characteristics to a user. If the flow and pressure decrease over time, a user may determine that the lung segment is not subject to collateral ventilation, and such segment is appropriately treated with ELVR. 
         [0013]    While the use of these procedures can identify patients likely to benefit from ELVR procedures, the need for improvements exists, particularly during assessment in lung passageways containing bodily secretions, such as mucus. For instance, if mucus enters the catheter lumen, the air flow into the lumen will be impeded, thus interfering with the monitoring function of the external console and may lead to erroneous results. Further, in catheters utilizing an inflatable balloon, the balloon might distend due in some part to bubbles formed by mucus. This causes the catheter, to lean into the passageway, potentially blocking the opening. Further, when an obturator is used to introduce the catheter and is later withdrawn, the obturator may act as a syringe or piston and draw mucus into the catheter lumen. 
         [0014]    For these reasons, it would be desirable to provide alternative and improved methods and apparatus for functional lung assessment within lung passageways containing secretions. In particular, it would be desirable to provide methods systems and devices that enhance catheter functionality by keeping secretions out of the catheter lumen, inhibiting secretion build-up within the passageways, cleaning secretions within the catheter lumen, or any combination thereof. At least some of these objectives will be met by the inventions described herein below. 
       BRIEF SUMMARY OF THE INVENTION 
       [0015]    The present application discloses devices and systems for preventing or inhibiting secretions from entering the lumen of a functional assessment catheter for the lungs. The functional assessment catheter comprises a catheter shaft for insertion into a lung passageway, the catheter shaft having a distal and a proximal end, and a lumen therebetween, a flow restrictive element disposed at the distal end of the catheter shaft to sealingly engage the lung passageway, wherein the flow restrictive element has an expanded configuration and a contracted configuration; and one or more of several modifications. 
         [0016]    In one aspect, the catheter is modified to comprise an expandable element to prevent or inhibit flow of secretions into the lumen, wherein the expandable element has an open configuration and a closed configuration. Such expandable element could be comprised of any material, including a mesh, an inflatable material or a rigid material. 
         [0017]    In another aspect, the catheter is modified to comprise a removable cover over the distal opening to prevent or inhibit secretion flow into the lumen. 
         [0018]    In another aspect, the distal end of the catheter is modified to comprise apertures to facilitate air flow, a liquid absorbable material to absorb secretions and thereby prevent or inhibit secretion flow into the lumen, or a hydrophilic material to repel secretions away from the catheter tip. In another aspect, the catheter comprises an internal element such as a coilable wire, an obturator configured to prevent secretions from being drawn into the lumen, or to actively remove the secretions. 
         [0019]    In another aspect, the catheter comprises an element to dry, aerate or aspirate the lung passageways. 
         [0020]    Other aspects of the invention include methods corresponding to the devices and systems described above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The invention has other advantages and features which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which: 
           [0022]      FIGS. 1   a  through  1   d  shows exemplary embodiments of a catheter providing a component that diverts secretions away from the distal opening of the catheter. 
           [0023]      FIGS. 2   a  and  2   b  show a catheter comprising an element that could collect secretions away from the catheter opening. 
           [0024]      FIG. 3  shows a catheter comprising an alternative embodiment that both attracts and collects the secretions away from the catheter opening. 
           [0025]      FIGS. 4   a  and  4   b  show another exemplary embodiment providing an element that attracts the secretions away from the distal opening of the catheter. 
           [0026]      FIGS. 5   a  and  5   b  show an alternative method of attracting secretions to a point distal to the catheter opening. 
           [0027]      FIGS. 6   a  through  6   d  show a catheter embodiment comprising various covers. 
           [0028]      FIG. 7  shows a cover for the distal tip that is incrementally removable. 
           [0029]      FIG. 8  contemplates methods for enhancing assessment even when the distal opening of the catheter is not centered within the lung passageway. 
           [0030]      FIG. 9  shows another embodiment to attract the secretions to a site distal from the catheter tip. 
           [0031]      FIG. 10  shows another embodiment to attract the secretions to a site distal from the catheter tip. 
           [0032]      FIG. 11  shows an alternative method of preferentially attracting the secretions to a site away from the inner lumen of the catheter. 
           [0033]      FIG. 12  contemplates a method for cleaning the inner lumen of the catheter once secretions have actually entered the catheter. 
           [0034]      FIG. 13  shows an alternative method of repelling the secretions by modifying the distal tip of the catheter. 
           [0035]      FIG. 14  shows a catheter attached to a syringe. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    Although the detailed description contains many specifics, these should not be construed as limiting the scope of the invention but merely as illustrating different examples and aspects of the invention. It should be appreciated that the scope of the invention includes other embodiments not discussed in detail. Various other modifications, changes and variations which will be apparent to those skilled in the art may be made in the arrangement, operation and details of the method and apparatus of the present invention disclosed herein without departing from the spirit and scope of the invention as described here. 
         [0037]    The present invention deals with methods systems and devices for preventing secretions from impeding the function of a pulmonary assessment catheter, hereinafter referred to simply as a catheter. 
         [0038]    The various catheter embodiments described herein may be used singularly or in combination. In one aspect, secretions can be prevented from impeding the function of the catheter by preventing the secretions from entering the catheter lumen. Additionally or alternatively, secretions build-up in the airway could be prevented or inhibited. Additionally or alternatively, secretions that collect within the airway could be removed. Additionally or alternatively, the secretions could be repelled away from the distal tip of the catheter. 
         [0039]      FIG. 1   a  shows an exemplary embodiment providing an expandable element that attracts the secretions away from the distal opening of a catheter  100  and precludes secretion entry into the catheter  100  during transport to the assessment site. Catheter  100  optionally comprises an expandable occluding member near its distal end, for example an inflatable balloon  101 . A mesh  110  capable of forming a basket-like configuration is attached at a point proximal to the distal tip of the catheter  100 , and distal to the balloon  101 . The mesh  110  is composed of a biocompatible shape-memory material, for example nitinol. Optionally, the mesh  110  may comprise a coating, for example, silicone, at least on some portion thereof. In its initial configuration, the mesh  110  forms a cover for the distal opening of the catheter  100 . The cover remains closed, as shown in  FIG. 1   a , while the catheter  100  is being transported to the assessment site. Secretions will thus be precluded from entering the lumen of the catheter  100  during such transportation. The proximal end of the mesh  110  is coupled to an elongate component  111 , for example a wire or an obturator, configured to manipulate the mesh  110 . Prior to deployment of the mesh  110 , the elongate component  111  constrains the mesh  110  and prevents the mesh from expanding to its shape memory configuration. At the assessment site, the mesh  110  will be deployed by retracting the elongate component  111  and thereby releasing the mesh  110  from constraint to expand to its shape memory. Upon deployment, the mesh  110  obtains the configuration shown in cross section in  FIG. 1   b . In this configuration, the secretions would be caught within the outer diameter of the mesh  110 , and would thus be diverted away from the distal tip of the lumen. Further, due to the surface tension of the secretions, the secretions would tend to pool within the mesh  110 , and thus, secretion entry into the lumen would be delayed or eliminated. Simultaneously, the open configuration of the mesh  110  keeps the lumen of catheter  100  centered within the lung passageway, rather than leaning towards a wall within the lung passageway. 
         [0040]    Alternatively or additionally, the mesh basket can be contained within the lumen of catheter  100 , as shown in  FIG. 1   c . In this embodiment, the catheter  100  comprises a mesh  120  in a collapsed configuration within the distal tip of the catheter  100  until the catheter  100  is moved to the assessment site. Catheter  100  optionally also comprises a balloon  101 . The mesh  120  is composed of a biocompatible shape-memory material, for example nitinol. Optionally, the mesh  110  may comprise an air-impermeable coating, for example, silicone, at least on some portion thereof. The proximal end of the mesh  120  is coupled to an elongate component  121 , for example a wire or an obturator, configured to manipulate the mesh  120 . The elongate component  121  maybe contained within the lumen wall of catheter  100  (as shown in  FIG. 1   c ), or it may be contained anywhere within or on the catheter  100 . Prior to assessment, the mesh  120  is deployed. The mesh  120  forms a ball-like structure of sufficient porosity to allow for air flow through the mesh  120 . Simultaneously, the secretions would tend to adhere to the outer diameter of the mesh  120 , and thus, secretion entry into the lumen of catheter  100  would be delayed or eliminated. 
         [0041]    Alternatively, the mesh forms a funnel-like structure  130  that allows air to be directed into the catheter lumen as shown in  FIG. 1   d . In this embodiment, catheter  100  comprises a mesh  130  in a collapsed configuration within the distal tip of the catheter  100  until the catheter  100  is moved to the assessment site. The mesh  130  is composed of a biocompatible shape-memory material, for example nitinol. Optionally, the mesh  130  may comprise an air-impermeable coating  132 , for example, silicone, at least on some portion thereof. The proximal end of the mesh  130  is coupled to an elongate component  131 , for example a wire or an obturator, configured to manipulate the mesh  130 . The elongate component  131  maybe contained within the lumen of catheter  100  (as shown in  FIG. 1   c ), or it may be contained anywhere within or on the catheter  100 . Prior to assessment, the mesh  130  is deployed to assume its shape memory of a funnel-like structure whose base is open to and engaged with the opening of catheter  100 . In this embodiment, the mesh  130  acts to simultaneously preclude secretion entry into the catheter lumen while directing air within the passageway into the lumen of catheter  100 . The secretions would tend to adhere to the outer diameter of the mesh  130 , and thus, secretion entry into the lumen of catheter  100  would be delayed or eliminated. Simultaneously, when deployed, mesh  130  with coating  132  acts to seal the passageway and center the catheter  100  within the passageway such that the only outlet for air is through the funnel-like structure into the catheter lumen. Thus, in this embodiment, the mesh  130  may replace the balloon  101  shown in previous embodiments. 
         [0042]      FIG. 2   a  shows an inflatable element  130  that could collect the secretions away from the opening of catheter  100 . In one embodiment, the inflatable element  130  is located distal to the balloon  101  on the catheter  100 . During transport, the distal tip of the inflatable element  130  is in an un-inflated state and covers the opening of the catheter  100  as shown in cross section in  FIG. 2   a . When inflated, the inflatable element  130  opens to reveal the catheter  100  lumen as shown in cross section in  FIG. 2   b . Simultaneously, when the inflatable element  130  is inflated open, secretions that have thus far accumulated are pushed outwards and away from the lumen of catheter  100 . Additionally, the inflatable element  130  keeps the distal tip of the catheter  100  centered within the lung passageway. Additionally or alternatively, the inflatable element  130  sealingly engages the lung passageway walls to perform the function of the balloon  101 . 
         [0043]      FIG. 3  shows an alternative embodiment to that shown in  FIG. 2 . This embodiment, shown in cross section, contemplates a collapsible rigid element  140 , that is manipulated through elongate components such as a wire  141  contained within or on the catheter  100 . The present figure shows the wire  141  contained within the wall of catheter  100 . The wire  141  can be pulled back and forth by the user to open and close the rigid element  140 . In this configuration, secretions will again pool along or behind the element  140 , rather than into the lumen of catheter  100 . 
         [0044]      FIG. 4   a  shows, in cross section, another exemplary embodiment providing an element that attracts the secretions away from the distal opening of the catheter  100 , and precluding secretion entry into the catheter  100  during transport to the assessment site. In this embodiment, the distal tip  200  comprises several strands  210  arranged to protrude radially from the distal tip  200 . The distal tip  200  thus looks similar to a brush with several bristles. The strands  210  are composed of any suitable biocompatible material. The configuration of the strands  210  allows for air to flow into the lumen of catheter  100  during the assessment. Simultaneously, the secretions adhere to the strands  210  and away from the opening of the catheter  100 . Optionally, the distal tip  200  of the catheter  100  also comprises several small apertures  211 . The apertures  211  in the distal tip  200  of the catheter  100  facilitate air flow into the catheter  100 . Optionally, the distal tip  200  could be manipulated within the passageway, for example in a backwards and forwards motion, to clean the area of assessment. Optionally, the strands  210  at the distal end may or may not be of a uniform length, and the strands  210  may form different cross sectional embodiments. Additionally, the distal section of the catheter  100  maybe detachably coupled or permanently affixed to the distal tip  200  of the catheter  100 . 
         [0045]    Additionally or alternatively, the strands  210  are connected to an elongate component contained within the catheter  100 , for example a wire or obturator  212  as shown in  FIG. 4   b . It is transported as such to the assessment site. At the assessment site, the component  212  with the strands is deployed out of the catheter lumen and into the lung passageway. In one aspect, the component  212  with the strands may be held stationary at a point distal to the end of the catheter  100 , to deflect the secretions. In another aspect, the component  212  with the strands may be moved along the lung passageway to clean the lung passageway and thereafter be held stationary at a point distal to the catheter  100 , or be retracted through the lumen of catheter  100 . Additionally, the strands  210  at the distal end may or may not be of a uniform length, and they may form different cross sectional embodiments. 
         [0046]      FIGS. 5   a  and  5   b  show an alternative embodiment for attracting secretions to a point distal to the catheter opening. In this embodiment, tines  220  protrude longitudinally from the distal end of the catheter  100 . The tines  220  could be made of any biocompatible material including nitinol, PTFE or silicone. During transport of catheter  100  to the assessment site, the tines  220  are held closed, for example using a ring  221  connected to a wire  222  contained within or on the catheter  100  as shown in  FIG. 5   a . At the assessment site, the tines  220  are opened, for example, by pulling on the wire  222  to retract the ring  221 , as shown in  FIG. 5   b . The tines  220  keep secretions from entering the inner lumen of the catheter  100 , by repelling the secretions if hydrophobic, or by preferentially attracting the secretions if hydrophilic. 
         [0047]    In another embodiment of the present invention, a cover could be provided to prevent the secretions from entering the lumen of catheter  100 , as shown in  FIGS. 6   a  through  6   d . The catheter  100  comprises a cover over the distal opening. Additionally, the catheter  100  comprises a wire  311  running the length of the lumen of catheter  100 , from the proximal end accessible by a user, to a cover at the distal end. The wire  311  maybe soft or rigid. It may be contained within the lumen wall of catheter  100 , or it may be contained anywhere within or on the catheter  100 . The cover remains over the distal opening of the catheter  100  during the catheter&#39;s movement to the assessment site. Prior to or during assessment, the cover is opened or closed by manipulating the wire. 
         [0048]    For example,  FIG. 6   a  shows a catheter  100  comprising a flap cover  310 , wherein one end of said cover is manipulatable by the wire  311 . In a closed position, the flap cover assumes the configuration as shown in position ( 1 ). When the wire  311  is pulled, the flap cover  310  is opened, as shown in position ( 2 ) to allow air to flow into the catheter  100  for assessment. 
         [0049]    Another example is provided in  FIG. 6   b  which shows a catheter  100  comprising a soft cover  320  that can be pushed forward or retracted by a wire  321 . The soft cover  320  can be made of any flexible material, such as a plastic film, that will provide little or no suction when it is withdrawn through the lumen of catheter  100 . During transport of the catheter  100 , the soft cover  320  covers the distal opening of the catheter  100 , thereby preventing or inhibiting secretion entry into the catheter  100 . Prior to or contemporaneous with assessment, the soft cover  320  is manipulated via the wire  321 , and the distal opening of the catheter  100  is open to receive air flow for assessment. 
         [0050]    Alternatively, the cover may encapsulate the distal opening of the catheter  100 , as shown in  FIG. 6   c . In this embodiment, the encapsulating cover  330  may encase the opening of the catheter  100 . The encapsulating cover  330  is attached to the wire  331  and can be pushed out into the lung passageway for the assessment procedure. 
         [0051]    In another embodiment, the cover may be a balloon  340  within the lumen of the catheter  100  as shown in  FIG. 6   d . The balloon  340  is attached to an elongate component, such as a wire  341 , of a small enough diameter to not act as a syringe when being pulled out. When inflated, the balloon  340  prevents secretion entry into the lumen of catheter  100 . During assessment, it may be deflated and pulled back with the wire  341  to leave an open catheter lumen. 
         [0052]      FIG. 7  shows a cover for the distal tip of the catheter  100  that is incrementally removable. The distal tip of the catheter  100  comprises a layered cover  340  with removable layers  345  made of a biocompatible material. The distal tip of the catheter  100  may or may not be perforated. The layers  345  are incrementally removable through one or more attachments, such as a wire  341  contained within the layers that extends the length of the catheter  100  to the user. Additionally, the biocompatible material may or may not be hydrophilic. In one embodiment, the distal tip of the catheter  100  may be transported to the assessment site, where the layers  345  are removed. In another embodiment, the layers  345  maybe removed incrementally during the assessment process. For example, in the embodiment with apertures in the catheter  100 , if secretions were to impede the air flow into the catheter  100 , several of the layers  345  could be removed to expose another set of apertures in the catheter  100 . 
         [0053]      FIG. 8  contemplates methods for enhancing assessment even when the distal opening of the catheter  100  is not centered within the lung passageway, for example, through distension of the inflatable balloon  101 . In this embodiment, the catheter  100  comprises apertures  410  within the catheter wall at the distal end. The apertures  410  maybe of any size or shape and maybe organized in any pattern while maintaining catheter  100  integrity. For example, the apertures  410  are elongate to allow the catheter  100  to maintain structural rigidity. The apertures  410  are scattered throughout the circumference of the catheter  100 , so that even if some of the openings of the catheter  100  are plugged with secretions, other openings will remain clear. Additionally, even if one portion of the catheter  100  leans against the lung passageway wall, the opposite portion will have some of the apertures  410  exposed to the gases contained within the lung passageway. Thus, the assessment function of the catheter  100  will not be impaired. 
         [0054]      FIG. 9  shows another embodiment to attract the secretions to a site distal from the catheter  100  tip. In this embodiment, an elongate coil  510  is deployed from the distal tip of the catheter  100 . The elongate coil  510  can be made of any biocompatible shape memory material, for example, Nitinol. While transporting catheter  100  to the assessment site, the elongate coil  510  is contained within the lumen wall of catheter  100  in a straight-line configuration, such as a wire  511 . The wire  511  is then pushed out of the distal opening and coils to assume the configuration of the elongate coil  510  within the lung passageway. Alternatively, the elongate coil  510  could be contained in a compressed, but coiled state within the lumen wall of the catheter  100  while transporting to the assessment site. The elongate coil  510  could then be deployed into the lung passageway, where it would expand into the lumen wall. The secretions along the wall passageways would adhere to the points of the elongate coil  510  in contact with the lung passageway wall rather than to the catheter  100 . Simultaneously, the inner diameter of the elongate coil  510  is open and allows enough air to flow into the assessment catheter  100 . In another embodiment, the elongate coil  510  would cover a portion of the distal end of the catheter  100 . 
         [0055]      FIG. 10  shows another embodiment to attract the secretions to a site distal from the catheter  100  tip. In this embodiment, a flat coil  520  is deployed from the distal tip of the catheter  100 . The coil can be made of any biocompatible memory-shape material, for example, nitinol. During catheter transport to the assessment site, the coil is contained within the lumen wall of catheter  100  in a straight-line configuration such as a wire  521 . The wire  521  is then pushed out of the distal surface and assumes an elongate coil  510  within the lung passageway. Alternatively, the flat coil  520  could be contained in a compressed, but coiled state within the lumen wall of the catheter  100  while transporting to the assessment site. The flat coil  520  is then deployed into the lung passageway, where it would expand to the diameter of the lung passageway. The secretions along the lung passageway walls would adhere to the points of the flat coil  520  in contact with the lung passageway wall. Simultaneously, the inner diameter of the flat coil  520  would allow for enough air flow into the assessment catheter  100 , thereby allowing for enough air to flow into the assessment catheter  100 . 
         [0056]      FIG. 11  shows an alternative method of preferentially attracting the secretions to a site away from the inner lumen of the catheter  100 . The distal tip of the catheter  100  comprises an addition, for example, a coating or a pad or a paper cone, of an absorbent material  610 . The absorbent material  610  can comprise any biocompatible, absorbent material, and may or may not be expandable. The coating of absorbent material  610  may end proximal to the distal end of the lumen during assessment. Secretions at the assessment site will thus be absorbed by the absorbent material. As some secretions are absorbed by the absorbent material  610 , it cohesively attracts more secretions. Thus, secretions that thereafter reach the assessment site will be attracted to the absorbent material,  610  rather than to the wall of catheter  100 . 
         [0057]      FIG. 12  shows an alternative method of repelling the secretions by modifying the distal tip of the catheter  100 . Traditionally, catheters are coated with PEBAX, which adheres to secretions. The present embodiment contemplates coating the distal tip with a hydrophobic substance  910 , for example PTFE, to divert secretions away from the lumen of catheter  100 . 
         [0058]      FIG. 13  contemplates a method for cleaning the inner lumen of the catheter  100  once secretions have actually entered the catheter  100 . In this embodiment, the inner lumen of the catheter  100  comprises an elongate inner component, such as a wire  710 , extending from the proximal end to the distal end, terminating at the distal end in a radial element  711 . The radial element  711 , shown in cross section in  FIG. 13 , has an outer diameter that is substantially similar to or slightly less than the inner diameter of the catheter  100 . If secretions enters the inner lumen of the catheter  100 , the radial element  711  is moved in a distal direction and past an amount of secretions that is to be removed, and subsequently back in a proximal direction, thereby moving the secretions contained within the lumen in a proximal direction, and optionally removing the secretions from the proximal end of the catheter  100 . Alternatively, the radial element  711  is moved in a distal direction to push secretions contained within the lumen in a distal direction. 
         [0059]    Another embodiment of the present invention contemplates alternative obturators. In this embodiment, the obturator has a different shape to simultaneously keep enough secretions out while at the same time exerting little or no negative pressure at the distal end of the catheter, thereby allowing the obturator to retract without drawing secretions. For example, the cross section of the obturator could be flower shaped, star shaped or cross shaped. Additionally or alternatively, the obturator could be hollow. A hollow obturator may additionally be used as an aspiration port to aspirate the lung passageway during transport, assessment, or any combination thereof. 
         [0060]    Additionally or alternatively, the obturator is configured to act like an Archimedes screw. Whenever the distal opening of the catheter  100  encounters secretions, the screw-shaped obturator will channel the secretions through the catheter  100  and away from the site of the assessment. 
         [0061]    In another embodiment of the present invention, one or more elements could be stored within or on the distal tip of the catheter to dry or otherwise preclude secretion build-up within the catheter. For example, a heating element may be used to dry the airway. Alternatively, medications that minimize mucus formation (.e.g., a mucolytic drug) may be coated on the catheter tip. The drug can diffuse slowly out of the coating into the surrounding tissue and provide extended release of a drug that can prevent or minimize mucus formation or breakdown the mucus that is secreted by the local tissue. 
         [0062]    In another embodiment of the present invention, at least one extra lumen and corresponding port may be provided to aspirate the passageways, flush the passageways, aerate the passageways, introduce a mucolytic drug into the passageways or any combination thereof. Alternatively, aspiration could occur via the existing lumens and ports. This is facilitated via a modified proximal portion of the catheter that is configured to introduce a fluid, (e.g., air) into the catheter. The introduced fluid would emerge from the distal end of the catheter with sufficient force to dry (if air or another gas is used) or push secretions that accumulate near or around the catheter mouth. 
         [0063]    An example of such a modified proximal portion is shown in  FIG. 14 . In this embodiment, the proximal portion of the device is configured to receive a fluid-propelling mechanism  800 . The fluid-propelling mechanism, such as a syringe, comprises a propellant portion  810  at the proximal end of the device, and a release valve  830  at the distal end of the device, and a pressurizer  820  therebetween. The propellant portion  810  further comprises an intake port  801 , a chamber  802  and a plunger  803 . A fluid is introduced into intake port  801  and is drawn into the chamber  802  in a syringe-like manner by pulling on plunger  803 . Intake port  801  is configured to be one-way or closable to preclude fluid from exiting intake port  801  from chamber  802 . Thereafter, the plunger  803  is pushed into chamber  802  to direct fluid into the pressurizer  820 . The fluid is precluded from exiting the distal end of mechanism  800  by release valve  830 , which remains in a closed position in a default state. Simultaneously, the fluid is held under pressure in the pressurizer  820 . When secretions are to be removed, release valve  830  is opened. The fluid, which has been accumulated under pressure in the pressurizer  820 , will exit the mechanism  800  and enter the catheter  100  (not shown). The fluid will have sufficient force that upon exiting the distal end of catheter  100  (not shown), it will dry or move secretions accumulating around the catheter end. 
         [0064]    In another embodiment, a catheter  100  is configured to maintain structural rigidity during transport without the use of an obturator. 
         [0065]    In another embodiment, the tip of catheter  100  is configured to be angular to enhance air flow into the catheter lumen. 
         [0066]    In another embodiment, the balloon  101  is inflated with a fluid, such as saline, to provide added stability. This will aid the catheter  100  to be centrally maintained within the lung passageway. Alternatively, the balloon  101  is manufactured to be structurally symmetrical when inflated. 
         [0067]    Any or all of the above embodiments may be combined or replaced with medication prior to the assessment procedure. 
         [0068]    While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.