Patent Abstract:
The present invention describes a device for placement in the thoracic cavity of a patient. The device is a cannula, tube or catheter for chest drainage. The device serves as a conduit for drainage of excessive fluid or air buildup in the chest to a receptacle outside the body. The device also serves to prevent influx of fluid or air into the chest cavity, thus preventing pneumothorax or infection. The device incorporates systems for anchoring the chest drainage cannula to the chest.

Full Description:
FIELD OF THE INVENTION 
     The field of this invention is general surgery, thoracic surgery, trauma and critical care. 
     BACKGROUND OF THE INVENTION 
     Chest drainage tubes are used following thoracic surgery, chest trauma or to treat certain medical conditions. The purpose of a chest tube is to remove buildup of excessive body fluids, contaminants or air from the thoracic cavity. The presence of an opening into the chest or thorax, created with or without a cannula will cause pneumothorax (collapsed lung). Negative pressure in the chest cavity is created by the chest muscles and diaphragm in order to cause lung expansion and resulting inspiration of a breath. Therefore, a hole in the chest will equalize pressure and prevent critical lung function, i.e. lung insufflation. Any cannula placed into a patient&#39;s chest cavity for drainage must be sealed to prevent pneumothorax from occurring. 
     Current chest drainage cannulae, also called chest tubes, drainage catheters or drainage cannulae, are flexible polymer tubes, placed into the chest cavity and extending outside the patient. 
     Chest drainage tubes are placed using a surgically invasive procedure. Generally, if a surgical incision into the chest has not been made, the chest tube is usually placed with the aid of an internal trocar that stiffens the chest tube and allows for easier chest wall penetration during placement. The procedure begins with a skin incision large enough to accommodate the diameter of the selected chest tube. Chest tubes are typically 8 mm to 10 mm diameter. The internal trocar, having a sharp point, is placed inside the chest tube. The pointed end of the trocar chest tube combination is pressed through the skin incision and plunged into the thoracic cavity through the muscle, fascia and fat layers of the patient, through the rib space and into the pleural cavity. The trocar is removed and the chest tube is clamped to prevent pneumothorax. 
     When drainage is required, the clamp is opened and fluid, air and contaminants are removed from the thoracic cavity. The fluid, air and contaminants typically are removed, forcefully, by use of external vacuum or pumping systems. The clamp is closed once drainage is completed to avoid reflux of fluid and air back into the chest cavity and possible generation of pneumothorax or influx of contaminants (i.e. infectious agents). 
     Placement of current chest drainage tubes is an invasive surgical procedure. With any invasive surgical procedure, there exists a risk of iatrogenic trauma to the patient. Significant training is required to safely perform these procedures and this training may not have been completed by emergency personnel who are the first line of treatment for many patients experiencing trauma. 
     Improved valving mechanisms would increase functionality of chest drainage tubes and overcome issues that occur with clamp application and removal. There are also fewer steps required of the medical practitioner in chest drainage when a tube with an internal valving mechanism is employed. There may also be a problem with a chest tube being pushed too far into the patient, resulting in kinking, compromised drainage and potential iatrogenic damage to internal organs. 
     SUMMARY OF THE INVENTION 
     This invention relates to a catheter, tube or cannula for draining fluid, air and contaminants from the chest and a method of placement. 
     The cannula of the present invention includes an internal, semi-automatic valving mechanism, which allows for fewer steps and minimizes the chance of leaving the chest tube open to atmosphere when drainage is completed. The cannula of the present invention also comprises an external movable fixation device to prevent inadvertently pushing the cannula too far into the patient. The minimally invasive placement method of the present invention is beneficial in not only the emergency setting but also in the hospital setting by reducing the chance of iatrogenic injury to the patient. 
     The cannula is a polymeric tube, preferably with a metal spiral winding to prevent kinking or collapse, which is fenestrated at or near the distal tip at a plurality of sites. The cannula includes an interior valve or seal, located inside the drainage lumen of the cannula, operably able to prevent reflux or efflux of fluid, air and contaminants to or from the chest. The cannula includes an intracorporeal fixation device, located internal to the patient, to prevent outward dislodgement of the chest tube from the chest. The cannula also includes an extracorporeal fixation device, located external to the patient to prevent inward movement of the chest tube. 
     In one embodiment, application of a vacuum at the proximal end of the cannula causes the internal valve to open thus allowing free flow of fluid, air and contaminants from the chest through the cannula and into the drainage system. The drainage system is typically a vacuum powered, water sealed suction device and collection reservoir. Removal of the vacuum causes exposure of the valve to atmospheric pressure and subsequent closure of the valve, thus reflux of fluid, air and contaminants into the chest is prevented. 
     Alternatively, the valve could be operated by application of positive pressure (above atmospheric) for closure of the valve and application of negative or zero pressure to open the valve. External feedback systems utilizing pressure sensors or other devices are used to ensure patient safety with the positive pressure valve closure embodiment. 
     In another embodiment, the internal valve is placed at the proximal end of the cannula. This valve is fabricated from a soft polymeric compound or foam with a central hole that is normally closed. Application of a mechanical force through the center of the valve, with a hollow obturator, for example, opens the valve and allows flow through the hollow obturator. Removal of the hollow obturator causes closure of the valve and prevention of reflux back into the thoracic cavity. 
     In yet another embodiment, the valve is a duckbill valve that passively prevents reflux back into the thoracic cavity while allowing drainage from the chest cavity under application of appropriate pressure drop across the valve. Such pressure drop can occur from an increase of intrapleural pressure caused by buildup of fluids or by application of a vacuum to the outlet side of the valve. 
     In all embodiments, the valve systems are, preferably, integral to the cannula and unable to be separated from the cannula when, for example, the patient rolls over and stresses the connection. 
     The drainage cannula of the present invention includes an intracorporeal fixation or retaining device that prevents the cannula from being removed inadvertently from the patient. This intracorporeal device is, for example, an elastomeric or inelastic (i.e. angioplasty-type) balloon affixed to the exterior surface of the cannula. The balloon is passed inside the chest cavity and is inflated with sterile liquids or air to prevent withdrawal through the hole or wound in the chest wall. Inflation typically occurs using a balloon inflation lumen in the cannula, inflation ports between the lumen and the balloon, and an inflation device external to the cannula. 
     Additionally, the drainage cannula of the present invention includes an extracorporeal fixation device that may comprise one or more clips that are affixed to the exterior of the cannula in a movable fashion. These clips are, preferably, located proximally to the internal fixation device or balloon. They may be moved against the chest wall and frictionally engaged to the cannula shaft to prevent the cannula from being forced too far into the patient. Such extracorporeal fixation devices could be retrofitted to existing chest tubes to improve the functionality of existing chest tubes. 
     The chest drainage tube of the current invention is placed in a minimally invasive procedure. Placement is accomplished by first performing a surgical skin nick and then placing a hypodermic needle into the pleural space of the patient at the site of the skin nick. A J-tip guidewire is placed through the hypodermic needle and the hypodermic needle is removed. A percutaneous access device or trocar is placed into the central lumen of the chest tube and over the guidewire and routed into the pleural space. 
     In a further embodiment, the cannula is steerable. This is accomplished by use of a malleable, bendable trocar that can be shaped prior to insertion into the patient. In another embodiment, steerability is obtainable by heat setting the cannula with a curved shape. Axially moving a rigid straight trocar into the bent portion of the cannula from the proximal end causes the curved shape to straighten out. This controllable bending is useful for negotiating tight turns in the patient. In another embodiment, steerability may be obtained using actuators on the surface or within the interior of the cannula to force bending of the cannula. These actuators are typically electrically powered. An actuator comprises electrical leads, a power source, a compressible substrate, and shape memory materials such as nitinol. Such actuators may be distributed along the length of the cannula. The actuators may be placed so as to oppose each other. Opposing actuators are activated one at a time and not simultaneously. 
     The combination of minimally invasive placement and reduced steps to operate the chest drainage tube will benefit patients and medical practitioners by reducing errors, minimizing trauma, increasing ease of use, and improving patient outcomes. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates the cannula, according to aspects of an embodiment of the invention; 
     FIG. 2 illustrates a cross-section of multi-lumen tubing used in fabrication of the cannula, according to aspects of an embodiment of the invention; 
     FIG. 3A illustrates a trocar useful for surgical placement of the cannula, according to aspects of an embodiment of the invention; 
     FIG. 3B illustrates the cannula with the trocar of FIG. 3A inserted therein, according to aspects of an embodiment of the invention; 
     FIG. 4A illustrates the percutaneous access trocar, guidewire and hollows needle for the method, according to aspects of an embodiment of the invention; 
     FIG. 4B illustrates the cannula with the percutaneous access trocar of FIG. 4A inserted therein, according to aspects of an embodiment of the invention; 
     FIG. 5A illustrates th cannula with the selectively openable, slotted distal drainage apparatus, wherein the slots are closed, according to aspects of an embodiment of the invention; 
     FIG. 5B illustrates th cannula with the selectively openable, slotted distal drainage apparatus, wherein the slots are opened, according to aspects of an embodiment of the invention; and 
     FIG. 5C illustrates a vertical cross section of the proximal end of the cannula, according to aspects of an embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a cannula, tube or catheter  10  of the present invention. The catheter  10  comprises a manifold or hub  12 , a valve or seal  14 , an extracorporeal fixation device  16 , an intracorporeal fixation device  18 , a plurality of drainage holes  20 , and a length of multi-lumen tubing  22 . In addition, the catheter  10  optionally comprises a valve housing  15 . The manifold  12  comprises a drainage adapter or fitting  24 , a valve-enabling adapter or fitting  26 , and an intracorporeal fixation-enabling adapter or fitting  28 . In this preferred embodiment, the intracorporeal fixation device  18  is a balloon, and the intracorporeal fixation-enabling adapter  28  is a balloon inflation adapter or fitting. The multi-lumen tubing preferably comprises a stiffening wire  30 . 
     FIG. 2 illustrates a cross-section of the multi-lumen tubing  22 . The multi-lumen tubing  22  comprises a drainage lumen  32 , a valve enabling lumen  34 , an intracorporeal fixation-enabling lumen  36 , and a wall  38 . In this preferred embodiment, the intracorporeal fixation-enabling lumen  36  is an inflation lumen. There is no communication between the drainage lumen  32 , the inflation lumen  36  and the valve enabling lumen  34 . The tubing material may be selected from any polymer such as, but not limited to, polyvinyl chloride, polyurethane, polyethylene and the like. The tubing  22  is, preferably, transparent or semi-transparent. At least a portion of the tubing  22  is preferably stiffened with a helical winding of material such as stainless steel, nitinol and the like. The stiffening  30  could also be created using corrugations in the tubing  22  or by addition of a strong polymer such as glass-filled polycarbonate instead of the metal helical winding. The stiffening member  30  serves the purpose of preventing collapse of the cannula  10  when vacuum is applied to the drainage lumen  32 . The stiffening member  30  also serves to prevent kinking when the cannula  10  is bent around a tight radius. 
     Referring to FIGS. 1 and 2, the manifold  12  connects to the proximal end of the length of multi-lumen tubing  22  such that the drainage adapter  24  connects to the drainage lumen  32 , the balloon inflation adapter  28  connects to the inflation lumen  36 , and the valve-enabling adapter  26  connects to the valve-enabling lumen  34 . There is no communication between the drainage adapter  24 , the balloon inflation adapter  28 , and the valve-enabling adapter  26 . The manifold  12  is typically molded from polymer, such as polyvinyl chloride, polycarbonate, acrilonitrile butadiene styrene (ABS), or the like. 
     The distal end of the multi-lumen tubing  22  comprises the plurality of drainage holes  20 . The drainage holes  20  connect the exterior of the catheter  10  with the drainage lumen  32 . The holes  20  are of sufficient size and quantity to allow for passage of fluid, thrombus and debris that might need to be removed from the chest cavity. The plurality of drainage holes  20  and the drainage lumen  32  may further be coated with an anti-thrombogenic coating of material such as, but not limited to, heparin. 
     The valve or seal  14  is preferably located in the drainage lumen  32  of the catheter  10 , between the manifold  12  and the drainage holes  20 . Alternatively, the valve or seal  14  may be mounted proximal to the manifold  12  or inside the manifold  12 . If the optional valve housing  15  is used, the housing  15  encircles the catheter  10  and is open to the drainage lumen  32 . The valve  14  sets inside the housing  15 . The intracorporeal fixation balloon  18  is located on the outside surface of the multi-lumen tubing  22 , between the manifold  12  and the drainage holes  20 , approximately 2 cm to 40 cm from the most proximal drainage hole. More preferably, the intracorporeal fixation device or balloon  18  is located between 5 cm and 20 cm from the most distal drainage hole. The balloon  18  is located over a balloon inflation port that allows communication between the balloon  18  and the inflation lumen  36 . The extracorporeal fixation device  16  is slidably located on the outside of the multi-lumen tubing  22 , between the manifold  12  and the intracorporeal fixation balloon  18 . 
     When the catheter  10  is in use, the manifold  12  connects to a drainage system through the drainage adapter  24 . The drainage adapter  24  is typically larger in diameter than the balloon inflation fitting  28  or valve-enabling fitting  26 . The drainage adapter  24  is capable of being connected to the gravity-fed, pump-driven or vacuum-fed drainage system and is most typically a ⅜ inch to ½ inch diameter hose barb. Standard drainage systems generally comprise a connector, a length of tubing and a reservoir. Optionally, a vacuum pump may be connected to the reservoir. 
     The manifold  12  also connects to an inflation system through the balloon inflation adapter  28 . The balloon inflation adapter  28  is typically a female luer fitting but may be any fluid-tight fitting suitable for use with an inflation syringe or the like. The standard balloon inflation system comprises a syringe, a volume of balloon inflation fluid such as sterile saline, air or radiopaque media, and a valve or stopcock. Additionally, the balloon inflation system could comprise a device, such as a jackscrew, to advance or withdraw a plunger on the syringe using mechanical advantage. 
     Additionally, the manifold  12  connects to a valve enabling system through the valve-enabling adapter  26 . The valve-enabling adapter  26  is, preferably, a female luer lock adapter, but could be another type of fluid-tight connection such as a threaded swage-lock, or the like. 
     FIG. 3A illustrates a trocar  40  useful for surgical placement of the cannula  10  of the present invention. The trocar  40  comprises a plunger  42 , a body  44  and a pointed tip or needle  46 . FIG. 3B shows the trocar  40  inserted into the drainage lumen  32  of the catheter  10 . The needle  46  extends out from the distal tip of the catheter  10  and the plunger  42  extends out from the proximal end of the catheter  10 . The internal trocar  40  stiffens the chest tube  10  and allows for easier thoracic penetration during placement. The internal trocar  40  is typically made from metal or polymer. The internal trocar  40  is, optionally, fabricated to be malleable. Medical personnel make a skin incision large enough to accommodate the diameter of the chest tube  10 . Chest tubes  10  are typically 8 mm to 10 mm diameter. The pointed needle  46  of the trocar chest tube combination  40 , 10  is pressed against the skin incision. Medical personnel push the plunger  42  to force the needle  46  into the thoracic cavity through the muscle, fascia and fat layers of the patient, through the rib space and into the pleural cavity. The trocar  40  is removed and the chest drainage tube  10  is in place. Fixation devices are enabled at this point. 
     FIGS. 4A and 4B illustrate a more preferred method of chest drainage tube placement. FIG. 4A illustrates a kit  48  comprising a hollow needle  50 , a guidewire  52 , and a tapered, flexible trocar  54 . The trocar  54  comprises a tip  56  and a handle  58 . First, the hollow needle  50  is inserted into the chest between the ribs, through the skin, fat, intercostal muscle, fascia and pleura. Next, the guidewire  52  is inserted through the needle  50  into the chest cavity to the desired location of the distal tip of the cannula  10  or beyond. Preferably, the guidewire  52  has a J-tip configuration at its distal end. 
     As shown in FIG. 4B, the tapered, flexible trocar  54  is inserted into the cannula  10  such that the tip  56  of the trocar  54  extends through the distal tip of the cannula  10  and the handle  58  of the trocar  54  extends through the proximal end of the cannula  10 . The needle  50  is removed and the flexible trocar-cannula combination  54 , 10  is threaded over the proximal end of the guidewire  52 . The flexible trocar-cannula combination  54 , 10  is moved over the guidewire  52  and inserted through the hole in the chest formed by the needle  50 . The tapered trocar  54  expands the chest hole and allows passage of the larger diameter back section of trocar  54  and cannula  10  into the patient. The trocar  54  and cannula  10  are advanced to the desired intrathoracic site along the route described by the guidewire. Once the tip  56  of the trocar  54  is in the desired location, the trocar  54  is removed from the proximal end of the cannula  10 . This method of cannula placement using the flexible, tapered trocar  54  requires a smaller incision than a standard trocar  40 . The incision may even be a percutaneous stick. The additional benefit is that the flexible trocar  54  and cannula  10  follow the path created by the guidewire  52  and route to the desired location without damaging tissue inadvertently. The tapered, flexible trocar  54  is typically fabricated from polymers such as PVC or polyethylene. The tapered, flexible trocar  54  exhibits column strength but is bendable. The tapered, flexible trocar  54  is able to flex easily along the path described by the guidewire  52 . 
     Referring to FIGS. 1 and 2, once the chest drainage tube  10  is placed in the patient&#39;s chest, the intracorporeal fixation balloon  18  is inflated. Balloon inflation fluid from the balloon inflation system is injected into the balloon inflation lumen  36  through the balloon inflation fitting  28 . The balloon inflation fluid travels through the balloon inflation lumen  36  to the balloon inflation port. The balloon inflation fluid travels through the balloon inflation port into the balloon  18 , inflating the intracorporeal fixation balloon  18 . The valve or stopcock on the balloon inflation system is closed to maintain the balloon  18  in the inflated configuration. The stopcock remains attached to the balloon inflation adapter to prevent unwanted balloon deflation. The balloon  18  is inside the patient&#39;s chest and is larger than the chest incision. The balloon  18  prevents the chest drainage tube  10  from inadvertently being pulled out of the patient. The balloon inflation fluid is selectively drained from the intracorporeal fixation balloon  18  by opening the stopcock to deflate the balloon  18  and allow the cannula  10  to be removed from the patient&#39;s chest. 
     In another embodiment, the intracorporeal fixation device  18  is an expandable region of cylindrical material with longitudinal slits or slots, a distal ring and a proximal ring. The rings and interconnecting slotted cylinder are disposed coaxially and concentrically around the cannula  10  shaft. The distal ring is connected to a control rod routed through the intracorporeal fixation lumen  36  to a control handle on the proximal end of the cannula  10 . When the cannula  10  is in place, the control rod is pulled, causing the distal ring of the intracorporeal fixation device  18  to pull along the cannula  10  shaft, toward the proximal ring. This causes the slit cylinder to collapse in length and the cylinder material between slits expands in diameter, forming a starburst pattern. A locking mechanism at the proximal end of the cannula  10  keeps the control rod from moving once the intracorporeal fixation device  18  is opened in the desired position. This system functions like a moly-bolt or drywall anchor to keep the cannula  10  from being removed from the chest inadvertently. The control rod may be unlocked and the distal ring advanced distally to contract the anchor around the cannula  10  so the cannula  10  may be removed from the patient. Optionally, holes or openings in the cannula  10  that connect with the drainage lumen  32  may be disposed underneath the slots or slits of the intracorporeal fixation device  18  thus providing additional chest drainage ports when the intracorporeal fixation device  18  is in the open position. 
     In addition to enabling the intracorporeal fixation device  18 , the extracorporeal fixation device  16  is also enabled once the catheter  10  is in place in the patient&#39;s chest. The extracorporeal fixation device  16  is located outside the chest and is disabled to allow the fixation device  16  to slide over the exterior of the catheter  10 , into place, against or close to the patient&#39;s skin. The extracorporeal fixation device  16  is enabled and forcibly stops sliding, preventing the chest drainage tube  10  from inadvertently being pushed farther into the patient&#39;s chest. 
     In a preferred embodiment, the extracorporeal fixation device  16  is a lockable clip device. When the lock is open, the extracorporeal fixation device  16  slides over the catheter  10 . When the desired location on the catheter  10  is reached, the lock is closed and the extracorporeal fixation device  16  engages the catheter  10  with enough force to make dislodgement of the fixation device  16  relative to the cannula or catheter  10  difficult, but with insufficient force to crimp or restrict the catheter  10  or the lumens  32 , 34 , 36 . The clip  16  is considerably larger than the diameter of the catheter  10  and the incision in the chest and, preferably has atraumatic rounded edges where it contacts the patient. At least one lateral dimension of the external fixation device or clip  16  is generally between 0.25 and 2 inches. More preferably, the external fixation device or clip  16  is between 0.5 and 1.0 inches in lateral dimension. 
     In another embodiment, the extracorporeal fixation device  16  is an inflatable balloon. The extracorporeal fixation balloon  16  may be inflated from the balloon inflation lumen  36  used to inflate the intracorporeal inflation balloon  18 . Alternatively, the extracorporeal inflation balloon  16  may be inflated from an additional balloon inflation lumen. 
     In yet another embodiment, the extracorporeal fixation device  16  is an opposably engaged spring clip, which encircles the catheter  10 . When the spring is compressed, the clip  16  is slid to the desired location on the catheter  10 . When the pressure on the spring is released, the clip  16  is locked into place on the catheter  10 . A similar type of spring clip is used to secure a drawstring on a sleeping bag. A further embodiment of the extracorporeal fixation device  16  is a rocking clip that slides when it is tilted relative to the lateral axis of the cannula  10  and locks when it is in the plane perpendicular to the axis of the cannula  10 . 
     In another embodiment, the extracorporeal fixation device  16  comprises a penetrable polymeric tab to allow suture passage and attachment of the extracorporeal fixation device  16  to the patient&#39;s skin with suture. The distal side of the extracorporeal fixation device  16  may comprise an adhesive layer to facilitate not only fixation but provide a contamination barrier at the entry site. The extracorporeal fixation device  16  optionally comprises a hole located somewhere on its structure, through which suture may be passed to facilitate attachment to the patient&#39;s skin. 
     In yet another embodiment, the extracorporeal fixation device  16  slides over a plurality of bumps or detents on the cannula  10  exterior surface. These bumps or detents serve to prevent axial motion of the extracorporeal fixation device except under substantial selective manual force. The extracorporeal fixation device  16  may additionally have a ratcheting mechanism that allows for axial motion toward the patient but prevents motion in the reverse direction away from the patient. 
     The extracorporeal fixation device is useful to retain not only drainage tubes but also any type of catheter in place in the patient. 
     Once the catheter  10  is placed in the patient&#39;s chest, the valve  14 , which is normally closed, prevents pneumothorax from occurring. The normally closed valve  14  seals the drainage lumen  32 . When the medical personnel require chest drainage, the valve  14  is enabled or opened to allow fluid, air and contaminants to drain from the chest drainage tube  10 . 
     In one embodiment, the valve-enabling lumen  34  is connected through the valve-enabling adapter  26  to a vacuum system. The typical vacuum system is operated by an electrical vacuum pump and regulator to maintain a low level vacuum of 1 to 100 mm Hg. Preferably, the vacuum is maintained at a level of 1 to 20 mm Hg. When the vacuum system is activated, a vacuum is drawn through the valve-enabling lumen  34  and the valve  14  opens. Stopping the vacuum system causes the valve  14  to close and seal the drainage lumen  32 . 
     The preferred vacuum activated valve embodiment  14  is one or more balloons mounted within the drainage lumen  32  of the cannula  10 . More preferably, the balloons  14  are exposed to the drainage lumen  32  but reside within the optional valve housing  15  that is larger than the diameter of the drainage lumen  32 . The collapsed balloons  14  reside within the housing  15  and do not impinge on the drainage lumen  32  where they could impede passage of the trocar  40  or  54 . The balloons  14  are maintained in their collapsed state and out of the drainage lumen  32  by application of a vacuum through the valve-enabling adapter  26  and the valve-enabling lumen  34 . An optional stopcock on the valve-enabling adapter  26  is closed to maintain the vacuum until it is desired to close the drainage lumen seal  14 . The valve housing  15  is fabricated, preferably, from transparent materials in order to allow for visualization of valve function and verification of drainage lumen patency. The balloons  14  are made with open cell foam. Such open cell foams are typically made from polyurethane materials and the spaces between the cells in the foam interconnect. The skin or surface of the balloon  14  is a fluid impermeable, elastomeric material such as latex, polyurethane, silastic and the like. 
     The balloons  14  are inflated, thus closing the valve  14 , by resilient expansion of the foam after fluid is allowed to flow back into the collapsed balloons. This may be done by removal of the vacuum or by opening the stopcock. When the valve  14  is closed, drainage through the drainage lumen  32  stops and the chest opening is sealed. The valve  14  is opened by application of a vacuum to the valve enabling lumen  34 . The vacuum system can be operably connected to the same vacuum system used for drainage of the thorax. In this way, the valve  14  automatically opens when drainage is activated. 
     Other valve embodiments  14  include balloons that are normally deflated and open. These valves  14  require that positive pressure be applied to inflate the balloons and occlude the drainage lumen  32 . Removal of the pressure or application of a vacuum causes the balloons to deflate and the valve  14  to open. Such valves  14  do not require the use of open cell foam cores but may require external devices to monitor drainage lumen parameters and ensure patient safety. 
     In another embodiment, the valve or seal  14  is made from a soft rubber or polymer. A central hole, slit or cross in the valve  14  allows for generation of potential space in this normally closed structure. In this embodiment, insertion of a hollow obturator through the valve-enabling adapter  26  and the central hole, slit or cross opens the valve  14 , permitting fluid, air and contaminants to pass through the hollow obturator. 
     In yet another embodiment, the valve or seal  14  is a duckbill or one-way valve permitting fluid, air and contaminants to flow from the chest but not permitting introduction of air into the chest. When the trocar  40  or  54  is advanced into the cannula  10 , the valve leaflets are moved into the open position to permit passage. This operation may be performed manually or automatically when trocar  40  or  54  insertion is required. The duckbill valve is typically fabricated from soft polymer materials such as silicone rubber, polyvinyl chloride, polyurethane and the like. The duckbill valve is preferably coated with materials such as heparin or silicone that prevent thrombosis and prevent unwanted permanent sealing of the valve leaflets. 
     FIG. 5A, FIG. 5B, and FIG. 5C illustrate another embodiment of the drainage holes  20  at the distal end of the catheter  10 . FIG. 5A shows the catheter  10  comprising a knob, lever, or handle  64 , a lock  66 , a control rod  72 , and a sleeve  68 . The sleeve  68  comprises a series of longitudinal slits or slots  60  and a rigid ring  62 . The proximal end of the sleeve  68  is affixed to the catheter  10  and the distal end of the sleeve terminates in the rigid ring  62  that slides over the catheter  10 . The sleeve is located over the plurality of drainage holes  20  at the distal end of the catheter  10 . The slits or slots  60  are disposed circumferentially around the sleeve  68 . The sleeve  68  is located approximately 20 cm or less from the distal end of the tubing  22  and is preferably located 10 cm or less from the distal end of the tubing  22 . The slots  60  are approximately 10 cm or less long and preferably 5 cm or less long. The slits or slots  60  are approximately 90 degrees apart and are preferably 45 degrees apart. The rigid ring  62  is operably attached to a control rod  72  running through one of the lumens of the multi-lumen tubing  22  and extending to the proximal end of the cannula  10 . As shown in FIG. 5C, the control rod  72  is terminated at the proximal end of the cannula  10  with the knob, handle or lever  64  for manual activation. In FIG. 5A, the slots  60  are closed. 
     FIG. 5B shows the distal tip of the cannula  10  when the control rod  72  is retracted and the slots  60  are open. As the control rod  72  is retracted proximally, the distal ring  62  moves proximally, and the slits or slots  60  expand radially and increase their opening size, thus exposing the drainage holes  20  and providing drainage. The control rod  72  may serve an additional purpose of activating the intracorporeal fixation device  18 . The lock  66  at the proximal end of the cannula  10  causes the control rod  72  to maintain its position until reversal is desired. The optional lever  64  provides mechanical advantage and makes it easier to move the control rod  72 . 
     In another embodiment, the slots  60  are located in the wall  38  of the multi-lumen tubing  22  and connect the exterior of the catheter  10  with the drainage lumen  32 , replacing the drainage holes  20 . As the control rod  72  is retracted proximally, the slits or slots  60  expand radially and increase their opening size, thus providing drainage. 
     In a further embodiment, the cannula  10  of the present invention comprises at least one flexible control rod  72  extending from the distal tip of the cannula  10  to the proximal end of said cannula  10 . The control rods  72  are slideably disposed within one of the lumens of the multi-lumen tubing  22 . The control rods  72  are disposed off-center and terminate at or near the proximal end of the cannula  10  with a handle. The control rods  72  are fabricated from wire, polymer fiber or other flexible material. The cannula  10  further comprises an area of increased flexibility proximal to the distal attachment point of the control rod  72  to the cannula  10 . 
     By withdrawing the control rod or rods  72  proximally, the cannula tip may be made to bend in a controlled direction in the area of increased flexibility. Such selective steerability is useful in advancing the cannula  10  through tortuous anatomy. 
     Alternatively, the cannula  10  of the present invention comprises a plurality of shape-memory actuators disposed longitudinally along the flexible region of the cannula. The shape-memory actuators are made from nitinol wire or from nitinol deposited over a flexible corrugated substrate, typically silicone rubber. The nitinol actuators are electrically wired through one or more of the cannula lumens to the proximal end of said cannula  10 . An electrical power source selectively connected to the wires at the proximal end of the cannula  10  causes heating of the nitinol wires and activation of shape-memory properties, which expand or contract the nitinol. Such controllable expansion or contraction of the nitinol causes the cannula  10  to experience localized forces that further cause the cannula  10  to bend and to be steerable. 
     The cannula  10  of the present invention is useful during or after many thoracic surgeries and will benefit many patients in the emergency setting. The system is easier to place in the patient than standard chest drainage tubes and may be placed by personnel with less training than physicians (e.g. paramedics). The system is less likely to be misused than standard chest drainage tubes. 
     The cannula  10  of the present invention may be used for abdominal drainage, thoracic drainage, peritoneal dialysis and other procedures. The invention is not limited solely to thoracic procedures but to general mammalian body cavity drainage and/or catheterization. 
     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is therefore indicated by the appended claims rather than the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Technology Classification (CPC): 0