Patent Publication Number: US-2022218962-A1

Title: Systems and methods for percutaneous drainage

Description:
FIELD OF DISCLOSED SUBJECT MATTER 
     The disclosed subject matter is directed to systems and methods for percutaneous drainage, for example, for the evacuation of abnormal, possibly infected, fluid collections from the body. 
     DESCRIPTION OF RELATED ART 
     Pathologic fluid can build up in a body due to infection/inflammation (i.e., an abscess), visceral obstruction/perforation (i.e., blockages of the urinary or biliary tracts), and/or hemorrhage (i.e., a hematoma). The fluid can be drained using an image-guided percutaneous drainage system. For example, using computed tomographic (CT), sonographic (US), and/or fluoroscopic (XR) guidance, medical practitioners (e.g., interventional radiologists) can non-invasively visualize abnormal fluid collections and subsequently insert drainage catheters into the collections through the skin using minimally invasive techniques. 
     Drainage catheters can be hollow plastic tubes of variable length and luminal diameter, with the most commonly used type known as a “pigtail” catheter in reference to the looped shape that its distal end forms. Drainage catheters function via the presence of one or more side holes at their distal end, through which abnormal fluid can enter the lumen of the catheter and be collected into a bag attached to its proximal end. Drainage can occur under the force of gravity or intermittently applied bulb suction. The average dwell time for a drainage catheter can be about 28 days, and device failure secondary to luminal obstruction/occlusion by viscous fluid and/or particulate matter can occur about 25-30% of the time, regardless of tube diameter. Faulty drainage can result in the recrudescence of patient illness and can require repeat invasive procedures, which can include additional risks and costs, to prevent sepsis-related death. Research has shown that up to 85% of drainage catheters can require exchange at least once before removal, and 50% can undergo upsizing, even though larger diameters have been shown not to confer a significant advantage in luminal patency or required dwell time. 
     To help maintain luminal patency, healthcare providers, as well as patients and/or caregivers, can be instructed to manually inject a defined volume of sterile saline into the catheter at scheduled frequencies. This can increase luminal lubricity, dislodge adherent debris from the catheter walls and side holes, and reduce the viscosity of draining fluid. However, this intervention is not always effective, and non-compliance with instructions is a common problem. Forgetting to flush catheters, injecting too little or too much fluid, and substitution of non-sterile tap water for sterile saline are common reasons for catheter occlusion, delayed healing, and additional complications, such as catheter-associated superficial or deep tissue infections. 
     Furthermore, patients commonly report the negative psychosocial effects of living with one or more drainage catheters for prolonged periods of time. The tubes and waste collection bags can be physically cumbersome, uncomfortable, unsightly, and socially stigmatizing. 
     Accordingly, there is a need for improved systems and methods for percutaneous drainage. 
     SUMMARY 
     The purpose and advantages of the disclosed subject matter will be set forth in and apparent from the description that follows, as well as will be learned by practice of the disclosed subject matter. Additional advantages of the disclosed subject matter will be realized and attained by the methods and systems particularly pointed out in the written description and claims hereof, as well as from the appended figures. 
     To achieve these and other advantages and in accordance with the purpose of the disclosed subject matter, as embodied and broadly described, the disclosed subject matter is directed to systems and methods for percutaneous drainage. For example, a system for percutaneous drainage of a drainage site includes a catheter, a drain tube, a first pump, a flush tube, a second pump, and a controller. The catheter includes a catheter wall extending from a proximal end portion of the catheter to a distal end portion of the catheter, the distal end portion of the catheter configured for placement within the drainage site, a septum disposed within the catheter wall and extending from a proximal end portion of the catheter to a distal end portion of the catheter, a drain lumen defined by a first portion of the catheter wall and the septum, the drain lumen extending from the proximal end portion of the catheter to the distal end portion of the catheter, and a flush lumen defined by a second portion of the catheter wall and the septum, the flush lumen extending from the proximal end portion of the catheter to the distal end portion of the catheter, wherein the flush lumen is separated from the drain lumen by the septum. The drain tube has a first end portion coupled to the drain lumen at the proximal end portion of the catheter, and a second end portion coupled to a waste collection container. The first pump is coupled to the drain tube between the first end portion of the drain tube and the second end portion of the drain tube. The flush tube includes a first end portion coupled to the flush lumen at the proximal end portion of the catheter, and a second end portion coupled to a flush material container having a flush material disposed therein. The second pump is coupled to the flush tube between the first end portion of the flush tube and the second end portion of the flush tube. The controller is coupled to the first pump and the second pump for controlling the first pump and the second pump. The septum has at least one septal hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen and the flush lumen are in communication via the at least one septal hole. The catheter wall has at least one wall hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen is in communication with the drainage site when the distal end portion of the catheter is placed within the drainage site. 
     The volume of the drain lumen can be equal to a volume of the flush lumen. The volume of the drain lumen can be greater than the volume of the flush lumen. The at least one septal hole can include a plurality of septal holes. The at least one septal hole can include a distal hole having a first diameter and a proximal hole having a second diameter, the second diameter being different than the first diameter. The second diameter can be smaller than the first diameter. The at least one septal hole and the at least one wall hole can be offset. 
     The system can include a pressure sensor or flow monitoring sensors coupled to the drain tube and the controller. The system can include a housing having the first pump, the second pump, and the controller disposed therein. The system can include an injection port coupled to the flush tube. The system can include a syringe coupled to the injection port by a third tube and/or the system can include a third pump coupled to the injection port by a third tube. 
     In accordance with the disclosed subject matter, a catheter for percutaneous drainage of a drainage site is provided. The catheter can include a catheter wall extending from a proximal end portion of the catheter to a distal end portion of the catheter, the distal end portion of the catheter configured for placement within the drainage site; a septum disposed within the catheter wall and extending from a proximal end portion of the catheter to a distal end portion of the catheter; a drain lumen defined by a first portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter; and a flush lumen defined by a second portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter, wherein the flush lumen is separated from the drain lumen by the septum. The septum can have at least one septal hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen and the flush lumen are in communication via the at least one septal hole. The catheter wall has at least one wall hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen is in communication with the drainage site when the distal end portion is placed within the drainage site. 
     In accordance with the disclosed subject matter, a method of percutaneous drainage of a drainage site is provided. The method can include inserting a catheter into the drainage site, the catheter including a catheter wall extending from a proximal end portion of the catheter to a distal end portion of the catheter, the distal end portion of the catheter configured for placement within the drainage site; a septum disposed within the catheter wall and extending from a proximal end portion of the catheter to a distal end portion of the catheter; a drain lumen defined by a first portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter; and a flush lumen defined by a second portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter, wherein the flush lumen is separated from the drain lumen by the septum; wherein the septum has at least one septal hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen and the flush lumen are in communication via the at least one septal hole; and wherein the catheter wall has at least one wall hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen is in communication with the drainage site when the distal end portion is placed within the drainage site. The method can further include withdrawing fluid from the drainage site via the drain lumen; identifying an occlusion in the drain lumen; and flushing a flush fluid through the flush lumen and into the drain lumen via the at least one septal hole and thereby removing the occlusion; and resuming withdrawing fluid from the drainage site via the drain lumen. 
     The method can include pausing withdrawing fluid from the drainage site via the drain lumen. Pausing can include reversing a direction of fluid flow in the drain lumen. The method can include monitoring a rate of fluid withdrawal from the drainage site. The method can include resuming withdrawing fluid from the drainage site via the drain lumen. The method can include monitoring a rate of change of the rate of fluid withdrawal from the drainage site. Identifying an occlusion in the drain can be based at least in part on one or more of the rate of fluid withdrawal from the drainage site and the rate of change of the rate of fluid withdrawal from the drainage site. The method can include monitoring a pressure in the waste lumen. The method can include monitoring a rate of change of the pressure in the waste lumen. Identifying an occlusion in the drain lumen can be based at least in part on one or more of the pressure in the waste lumen and a rate of change of the pressure in the waste lumen. 
     In accordance with the disclosed subject matter, a system for percutaneous drainage of a drainage site can include a catheter, a drain tube, a first pump, a flush tube, a second pump, and a controller. The catheter includes a catheter wall extending from a proximal end portion of the catheter to a distal end portion of the catheter, the distal end portion of the catheter configured for placement within the drainage site, a septum disposed within the catheter wall and extending from a proximal end portion of the catheter to a distal end portion of the catheter, a drain lumen defined by a first portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter, and a flush lumen defined by a second portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter, wherein the flush lumen is separated from the drain lumen by the septum. The drain tube has a drain tube having a first end portion coupled to the drain lumen at the proximal end portion of the catheter, and a second end portion coupled to a waste collection container. The first pump is coupled to the drain tube between the first end portion of the drain tube and the second end portion of the drain tube. The flush tube includes a first end portion coupled to the flush lumen at the proximal end portion of the catheter, and a second end portion coupled to a flush material container having a flush material disposed therein. The second pump is coupled to the flush tube between the first end portion of the flush tube and the second end portion of the flush tube. The controller is coupled to the first pump and the second pump for controlling the first pump and the second pump. The first portion of the catheter wall has at least a first wall hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen is in communication with the drainage site when the distal end portion of the catheter is placed within the drainage site. The second portion of the catheter wall has at least a second wall hole disposed therein proximate to the distal end portion of the catheter such that the flush lumen is in communication with the drainage site when the distal end portion of the catheter is placed within the drainage site. 
    
    
     
       DRAWINGS 
       The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. 
         FIG. 1A  is a schematic of an exemplary system for percutaneous drainage in accordance with the disclosed subject matter. 
         FIG. 1B  is a schematic of an exemplary system for percutaneous drainage in accordance with the disclosed subject matter. 
         FIG. 2  is a cut-away view of an exemplary catheter for use with the system of  FIG. 1A , in accordance with the disclosed subject matter. 
         FIGS. 3A-3C  provide cross-section views of exemplary catheters for use with the system of  FIG. 1A , in accordance with the disclosed subject matter. 
         FIG. 4  is a perspective view of an exemplary housing for use with the system of  FIG. 1A , in accordance with the disclosed subject matter. 
         FIGS. 5A and 5B  are perspective views of an exemplary base and cover, respectively, along with certain elements for use with the system of  FIG. 1A , in accordance with the disclosed subject matter. 
         FIG. 6  is a top-down, cut-away view of an exemplary housing, along with certain elements for use with the system of  FIG. 1A , in accordance with the disclosed subject matter. 
         FIG. 7  is a block diagram of certain elements for use with the system of  FIG. 1A , in accordance with the disclosed subject matter. 
         FIG. 8  provides a plurality of views of a wearable component for use with the system of  FIG. 1A , in accordance with the disclosed subject matter. 
         FIGS. 9A-9C  provide views of a graphical user interface for use with the system of  FIG. 1A . 
         FIG. 10  is a schematic of a portion of an exemplary system for percutaneous drainage including multiple drainage catheters, in accordance with the disclosed subject matter. 
         FIG. 11  illustrates a control unit coupled to one or more modular pumps, in accordance with the disclosed subject matter. 
         FIG. 12  is a plot of the results of suction over 20 minutes through a draining catheter in accordance with the disclosed subject matter using the three different suction conditions is shown 
         FIG. 13  is a schematic of an exemplary catheter in accordance with the disclosed subject matter used for computational fluid dynamics analysis, 
         FIG. 14  illustrates exemplary results of computational fluid dynamics analysis of a catheter, in accordance with disclosed subject matter. 
         FIG. 15  illustrates exemplary results of computational fluid dynamics analysis catheters employing varying flush strategies, in accordance with the disclosed subject matter. 
         FIG. 16  illustrates exemplary results of computational fluid dynamics analysis of catheters having variable septal hole locations, in accordance with the disclosed subject matter. 
         FIG. 17  illustrates exemplary results of computational fluid dynamics analysis of catheters having variable septal hole diameters, in accordance with the disclosed subject matter. 
         FIG. 18  illustrates exemplary results of computational fluid dynamics analysis of catheters having variable lumen volume ratios, in accordance with the disclosed subject matter. 
         FIG. 19  illustrates exemplary results of computational fluid dynamics analysis of catheters with or without outward flush holes, in accordance with the disclosed subject matter. 
         FIG. 20  illustrates exemplary results of computational fluid dynamics analysis of catheters with or without a distal end hole, in accordance with the disclosed subject matter. 
         FIG. 21  is a flow chart for a method for percutaneous drainage of a drainage site. 
         FIG. 22  is a schematic of an exemplary system for enteral feeding in accordance with the disclosed subject matter. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the various exemplary embodiments of the disclosed subject matter, exemplary embodiments of which are illustrated in the accompanying figures. As used in the description and the appended claims, the singular forms, such as “a,” “an,” “the,” and singular nouns, are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     Generally, and as set forth in greater detail below, the disclosed subject matter provided herein includes systems and methods for percutaneous drainage. For example, a system for percutaneous drainage of a drainage site includes a catheter, a drain tube, a first pump, a flush tube, a second pump, and a controller. The catheter includes a catheter wall extending from a proximal end portion of the catheter to a distal end portion of the catheter, the distal end portion of the catheter configured for placement within the drainage site, a septum disposed within the catheter wall and extending from a proximal end portion of the catheter to a distal end portion of the catheter, a drain lumen defined by a first portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter, and a flush lumen defined by a second portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter, wherein the flush lumen is separated from the drain lumen by the septum. The drain tube has a first end portion coupled to the drain lumen at the proximal end portion of the catheter, and a second end portion coupled to a waste collection container. The first pump is coupled to the drain tube between the first end portion of the drain tube and the second end portion of the drain tube. The flush tube includes a first end portion coupled to the flush lumen at the proximal end portion of the catheter, and a second end portion coupled to a flush material container having a flush material disposed therein. The second pump is coupled to the flush tube between the first end portion of the flush tube and the second end portion of the flush tube. The controller is coupled to the first pump and the second pump for controlling the first pump and the second pump. The septum has at least one septal hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen and the flush lumen are in communication via the at least one septal hole. The catheter wall has at least one wall hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen is in communication with the drainage site when the distal end portion of the catheter is placed within the drainage site. 
     Although systems and methods are described herein with respect to particular percutaneous drainage, such as abscess drainage, the systems and methods can be used for a wide variety of clinical applications common to fields of interventional radiology and/or surgery. For example, the systems and methods described herein can be used for percutaneous thoracostomy (i.e., pleural drainage of fluid (liquid and/or gas) and/or pleurodesis); percutaneous pericardiostomy (i.e., pericardial drainage); percutaneous nephrostomy, nephroureterostomy, and/or cystostomy (i.e., drainage and/or irrigation within the urinary tract); percutaneous cholecystostomy and biliary (internal-external, external) drainage; percutaneous chemical ablation and/or sclerosis of cystic lesions, recurrent fluid collections (such as lymphoceles and other disorders of the lymphatic system), and/or hollow viscera (such as gallbladder in candidates deemed unsuitable for cholecystectomy); percutaneous esophagostomy gastrostomy, gastrojejunostomy, jejunostomy, and/or cecostomy (i.e., the alimentary/digestive tract); percutaneous ventriculostomy and thecal sac drainage for hydrocephalus/CSF hypertension; and percutaneous thrombolysis/thrombectomy/embolectomy for thromboembolic disease of the arterial and/or venous vasculature. 
     As described in greater detail below, the systems and methods described herein can rapidly evacuate unwanted fluid from the body using a system of motorized pumps at a faster rate when compared to standard drainage catheters, which typically rely on gravity or manual suction bulbs. The system and methods can detect changes in catheter pressure dynamics and fluid volume transfer via programmable sensor indicative of various system states, such as impending luminal occlusion, satisfactory completion of drainage, and/or complications, such as hemorrhage, pneumothorax, or fistula formation. The system and methods can prevent and/or mitigate catheter occlusion via a self-flushing, dual lumen design using sterile saline and/or adjunctive chemical/biologic agents. Systems and methods described herein can include programmable aspiration/flush profiled tailored to the composition (e.g., volume, viscosity), of a fluid collection, and can remotely monitor and control drainage catheter system performance via wireless technology. This can allow healthcare providers and/or patients the ability to adjust pump settings, such as aspiration and/or flush rates, volumes, and/or frequencies. Furthermore, the systems and methods can collect and analyze biometric data (e.g., patient body temperature, which can indicate sepsis). The collected data can be used to guide therapeutic decisions. The systems described herein can be housed in a self-contained and powered wearable assembly with separate enclosures for electronics (e.g., pumps, circuit boards, power supply), sterile flush, and waste collection, with disposable components to allow for reuse. 
     Referring to  FIGS. 1A-3  for purpose of illustration and not limitation, the disclosed system  100  can be configured for percutaneous drainage. The system  100  can include a catheter  10 , a drain (also referred to as efflux, aspiration, and/or waste) tube  50 , flush (also referred to as influx) tube  51 , connector  52 , a drain (also referred to as efflux, aspiration, and/or waste) pump  30 , a flush (also referred to as influx) pump  40 , a controller  60 , a waste collection container  70 , and a flush material container  71 . The flush material container  71  can include a flush material  72 . The flush material  72  can be saline, or other suitable flushing material. For example, sterile normal (0.9%) saline without or with one or more of the following: antimicrobial agents (e.g., antibiotic and antifungal medications) or therapeutic enzymes (e.g., tissue plasminogen activator [tPA], dornase, collagenase, and others) can be used. System  100  can include a remote device  67  in communication with the controller  60 . The waste collection container  70  can have a pre-defined degree of baseline vacuum/negative internal pressure. 
     As described in greater detail below, the catheter  10  can be placed in a drainage site  2  of a patient. The system  100  can drain fluid from the drainage site  2  using a first lumen (e.g., the drain lumen  15  described below). The system  100  can maintain the patency of the first lumen by (1) using a second lumen (e.g., the flush lumen  16  described below) to periodically delivery a local diluent, and/or (2) reversing flow in the first lumen to dislodge occlusive debris, or both (simultaneously or non-simultaneously). 
     The catheter  10  can include a catheter wall  11  extending from a proximal end portion  12  of the catheter  10  to a distal end portion  13  of the catheter  10 . The distal end portion  13  of the catheter  10  can be configured for placement in a drainage site  2 . The catheter  10  can be a dual lumen catheter  10 . For example, catheter  10  can include a septum  14  disposed within the catheter wall  11  and extending from a proximal end portion  12  of the catheter  10  to a distal end portion  13  of the catheter  10 . A first portion of the catheter wall  11 A and septum  14  can define a drain lumen  15  (also referred to as the efflux, aspiration, and/or waste lumen) and a second portion of the catheter wall  11 B and the septum can define a flush lumen  16  (also referred to as the influx lumen). Each of the drain lumen  15  and the flush lumen  16  can extend from the proximal end portion  12  of the catheter  10  to the distal end portion  13  of the catheter  10 . The volumetric proportions between the drain lumen  15  and the flush lumen  16  can be equal (i.e., 50-50;  FIG. 3A ), or unequal, for example, 80-20, 70-30 ( FIG. 3B ), 60-40 ( FIG. 3B ), or any other suitable ratio to achieve the desired flow dynamics. Although described as a particular dual lumen catheter (i.e., two lumens separated by a septum), any suitable dual lumen catheter can be used, including, for example, catheters with coaxial lumens, or with a septum that can be linear, curvilinear, or helical, twisting along the length of the longitudinal axis of the catheter, or two parallel cylindrical or hemicylindrical (or other shapes with flat edges) catheters fused along the length, either straight or where the lumens are twisted (intertwined) around along the long axis of the catheter. As another example, the drain lumen  15  or the flush lumen  16  can be incorporated into the catheter wall  11 . Additionally, the drain lumen  15 , flush lumen  16 , catheter wall  11  and septum  14  can have any suitable shape to achieve the desired flow dynamics. The materials of construction of the catheter  10  can be any suitable materials that are biocompatible and amenable to thermoplastic extrusion, a common method for multi-lumen catheter construction. For example, the catheter  10  can be silicone, polyurethane, polyethylene, polyvinyl chloride, polytetrafluoroethylene, nylon, or thermoresponsive polymers. The catheter walls can be non-braided and/or braided with thin filament material. 
     The septum  14  can include at least one septal hole  17  (e.g.,  17 A- 17 F; also referred to as fenestrations) along its length such that the drain lumen  15  and the flush lumen  16  are in communication via the septal holes  17 . For example, and as shown in  FIG. 2  for purpose of illustration and not limitation, septum  14  can include six septal holes  17 . The septal holes  17  can be disposed proximate to the distal end portion  13  of the catheter  10 . The catheter wall  11  can include at least one wall hole  18  (e.g.,  18 A-D) along its length such that the drain lumen  15  is in communication with the drainage site  2  when the distal end portion  13  of the catheter  10  is placed within the drainage site  2 . For example, and as shown in  FIG. 2  for purpose of illustration and not limitation, catheter wall  11  can include four wall holes  18 . The wall holes  18  can be disposed proximate to the distal end portion  13  of the catheter  10 . Additionally, or alternatively, the drain lumen can have an open distal end hole to provide additional communication with the drainage site or to allow the catheter  10  to be delivered over a guidewire. 
     In an exemplary embodiment, the catheter  10  can include at least one wall hole  18  in the second portion of the catheter wall  11 B along its length such that the flush lumen  16  is in communication with the drainage site  2  when the distal end portion  13  of the catheter  10  is placed within the drainage site  2 . In such an embodiment, the septum  14  can be provided without septal holes  17  or with one septal hole  17 . Such a catheter  10  can be used to deliver enzymatic and/or caustic agents such as detergent sclerosants to the injection site via flush lumen  16  which can lyse and/or otherwise break down complex components of a fluid collection, as well as iatrogenically induce an inflammatory response within the cavity to promote scarring and healing. The drain lumen  15  can be used to collect and remove the flush material, as well as the underlying pathologic fluid. 
     The wall holes  18  can be formed by any suitable means, for example, punches, drilling, or lasers. The septal holes  17  can similarly be formed by any suitable means. An inert and durable insert can be used when forming the septal holes  17  and/or wall holes  18  to prevent damage to the interior of the catheter wall  11  or septum  14 , as appropriate (e.g., where holes are not intended). The septal holes  17  can be offset from the wall holes  18 , for example, by delivering a puncturing tool at an angle through a wall hole  18  to the septum  14 . For example, a puncturing tool that fits through wall holes  18  can be used to create septal holes  17 . This can create septal holes  17  that can direct flush fluid back toward the wall hole  18  (for example, due to the relationship between septal holes  17 A,  17 B and wall hole  18 A). Furthermore, the septal holes  17  can be cut with an angle, and as such, the septal holes  17  can direct the flush fluid back towards the corresponding wall hole  18  located just proximally of the septal hole  17 . The septal holes  17  and the wall holes  18  can be placed at any suitable position along the septum  14  and catheter wall  11 , respectively, and can be any suitable size or shape to provide the desired flow dynamics, as described in greater detail below. The size of the wall holes  18  and septal holes  17  can vary along the length of the catheter  10 . For example, more distal septal holes  17  (e.g.,  17 A, B) can be larger than more proximal septal holes  17  (e.g.,  17 E, F). This can maintain roughly equivalent flow through the septal holes  17  along the length of the catheter. Alternatively, it can be desirable to provide higher rates of fluid flow through particular septal holes. Higher rates of flow through a particular septal hole can impact the patency of a corresponding or adjacent wall hole. For example, septal holes  17  can get progressively larger in diameter as fluid flows in the flush lumen  16  from the proximal end portion  12  of the catheter  10  to the distal end portion  13  of the catheter. Alternatively, distal septal holes  17  (e.g.,  17 A, B) can be smaller in diameter than proximal septal holes  17  (e.g.,  17 E, F). Although particular examples are described, any suitable septal holes  17  can be used to create communication between the flush lumen  16  and the drain lumen  15 , and any suitable wall holes  18  can be used to create communication between the drain lumen  15  and the drainage site  2 . Furthermore, it can be desirable to achieve greater flow velocity at wall holes  18 A and  18 B towards the distal end portion  13  of the catheter  10 , as wall holes towards the distal end portion  13  can be more prone to clogging during use. Although particular septal holes  17  and wall holes  18  are described, any suitable septal holes  17  and wall holes  18  can be used to achieve desired flow dynamics. For example, holes with various sizes, gradients of sizes along the length, different shapes (e.g., ovals, slits, polygonal, circle) can be used. Walls of holes can be straight, tapered, rounded, or curved. Holes can be staggered or aligned along any aspect of the catheter (e.g., helical). Exemplary arrangements for septal holes  17  and wall holes  18  are provided in greater detail below. 
     The distal end portion of the flush lumen  16  can be closed. For example, a distal plug  19  or other suitable means for closing the distal end portion of the of the flush lumen  16  can be provided. The distal plug  19  can prevent flush solution (e.g., sterile solution) from exiting the distal tip of catheter  10 , and can instead force the flush solution through the septal holes  17  into the drain lumen  15 . This can increase pressure in drain lumen  15  and can dislodge material blocking the drain lumen  15  or wall holes  18 . The flushing solution can also dilute more viscous bodily fluids to ease draining of the drainage site  2 . The distal plug  19  and or the distal end of catheter  10 , can be rounded to ease insertion through tissue and into the drainage site  2 . Although a particular system for closing the distal end portion of the flush lumen  16  is described, any suitable means for closing the distal end portion of the flush lumen  16  can be used. The distal end portion of the drain lumen  15  can be open which can allow additional communication with the drainage site  2  and/or can be used for delivery using a guidewire, for example, using over-the-wire catheter insertion via the Seldinger technique. 
     Catheter  10  can have a straight, pigtail, looped, or other curved configurations. A combination of one or more configurations/curvatures can be included in series, and one or more configurations/curvatures can be repeated in series. The catheter  10  can be deformable to allow for placement in a first configuration and then to transition to a second configurations. For example, a shape memory material can be used to transition the catheter  10  to the second condition to keep the catheter  10  in place. 
     In accordance with the disclosed subject matter, catheter  10  can include a taper in size from a larger proximal portion  12  to a smaller distal portion  13 , such that the body of the catheter can fully obturate the subcutaneous tunnel tract in the event that the distal portion  13  becomes dislodged from the drainage site  2 . A tapered outer diameter can also prevent peri-catheter leakage. Additionally, or alternatively, catheter  10  can include a short length of ribbing and/or grooved threading on the outer wall  11  along its proximal-mid segment, which can allow for a securing device to anchor the catheter. For example, a non-absorbable suture can be used to affix the catheter securely to the skin without sliding along the catheter&#39;s length. Alternatively, an inflatable balloon, mushroom-shaped silicone dome, serrated ring, or deployable T-tacks, which can slide down the length of the catheter to the level of the skin aperture, can anchor the catheter  10  to the subcutaneous soft tissues. 
     As shown in  FIG. 1B , for purpose illustration and not limitation, system  100 A includes each of the features of system  100 , and further can include syringe injection port  53  coupled to flush tube  51  and third tube  54 . Third tube  54  can be coupled to syringe  55  (or a third pump and reservoir). The syringe  55  can be used to deliver sclerosant, drugs, or other additional substances into the flush tube  51 . 
     Referring to  FIGS. 4-6  for purpose of illustration and not limitation, system  100  can include housing  80 . The housing can be, for example, an enclosure for housing some or all electronic components of system  100 . For example, housing  80  can house the drain pump  30 , flush pump  40 , and controller  60 . The housing  80  can include a base  81  and cover  82 . The base  81  and/or cover  82  can include mounting features  83  (e.g.,  83 A,  83 B) for supporting the various electronic components. The mounting features  83  can be, for example, M3 heat-set inserts, which can be configured to receive M3×10 mm socket head cap screws (SHCS). Although particular mounting features are described, any suitable mounting features  83  can be used, for example, screws, nails, or adhesives. Cover  82  can be fastened to the base  81  by any suitable means, for example, M3×10 mm SHCS. When fastened together, the base  81  and cover  82  can create a protective and insulating housing  80  for the electronic components. The housing  80  can be sized and shaped such that the housing  80  can be carried, for example, inside a wearable pack (described in greater detail below). 
     The drain pump  30  and flush pump  40 , which can be any suitable pumps, for example, 6V peristaltic pumps, can be mounted within the housing  80 . Similarly, the controller  60 , which can include any required or suitable electronics, such as a microcontroller  61  (for example, a Arduino Uno microcontroller), a motor driver  62  (for example, a L298N motor driver), a battery  63  (for example, a 200 mAh 9.6V Ni-MH battery), and an transmitter  64  (for example, an adafruit Bluefruit LE UART—Bluetooth Low Energy (BLE) transmitter) can be mounted within the housing  80 . Although particular elements for the drain pump  30 , flush pump  40 , and controller  60  are described, any suitable elements can be used. The housing  80  can also house a breadboard  65 , for example, on lid  82 . The breadboard  65  can be used to route battery power from the battery  63  to the microcontroller  61  and motor driver  62 , and can allow for modular, expandable off-board circuitry to be added as needed. Housing  80  can also include a pressure sensor  66  attached via a T-junction connector  84  to the drain tube  50 . The housing  80  can include load transducers or liquid level sensors at the flush material container  71  and waste collection container  70  to measure fluid volume and evacuated fluid flow. The pressure sensor  66  can include a diaphragm seal and utilize MEMS sensors. 
     The base  81  and cover  82  can each have a slot  85 ,  86  (respectively), that can correspond with the positions of the drain pump  30  and flush pump  40 , and allow for passage of the drain tube  50  and the flush tube  51  through both the base  81  and cover  82 , such that the drain tube  50  and flush tube  51  can interface with the respective drain pump  30  and flush pump  40 . For example, the drain tube  50  can extend from the waste collection container  70 , through the slot  86  in cover  82 , be routed to interface with drain pump  30 , followed by T-junction connector  84 , through slot  85  in the base  81 , and then coupled to the drain lumen  15  at the proximal end portion  12  of the catheter  10  via connector  52 . The flush tube  51  can extend from the flush material container  71 , through slot  85  in cover  82 , be routed to interface with the flush pump  40 , through slot  85  in base  81 , and then coupled to the flush lumen  16  at the proximal end portion  12  of the catheter  10  via connector  52 . 
     Referring to  FIG. 7  for purpose of illustration and not limitation, the battery  63  can provide power for one or more elements disposed in housing  80 . The battery  63  can be removable from the housing, for example, for recharging or replacement. Battery  63  can be coupled to breadboard  65 . A switch  69  can be provided between the battery  63  and the breadboard  65  for turning the device on and off. At breadboard  65 , power can be distributed to the transmitter  64 , microcontroller  61 , and motor driver  62 . 
     The microcontroller  61  can be used to provide logic for the transmitter  64 , motor driver  62 , drain pump  30 , flush pump  40 , and pressure sensor  66 . For example, the microcontroller  61  can be an Arduino Uno board and can be programmed in C++ in Arduino Integrated Development Environment (IDE). The microcontroller  61  can be coupled to the pressure sensor  66  to receive pressure measurements of the drain tube  50 . The microcontroller  61  can be coupled to the transmitter  64  to send and receive information (for example receiving operation instructions and sending pressure measurements or other measurements) to a remote device  67 , such as a computer (such as a laptop or desktop computer), a personal data or digital assistant (PDA), or other user equipment or tablet, such as a mobile phone or portable media player. The communication between the transmitter  64  and remote device  67  can be wired or via one or more of a network, radiofrequency, or wireless connections, such as Bluetooth. The microcontroller  61  can also be coupled to the motor driver  62 , which can be coupled to each of the drain pump  30  and the flush pump  40 . Accordingly, the micro controller can send control signals to the motor driver  62  (for example in the form of digital signals) and the motor driver  62  can send the signals, for example, pulse or step signals and direction signals (for example in the form of pump voltages) to the drain pump  30  and the flush pump  40 . Although particular arrangements are described, any suitable arrangements can be used for the electronic components to achieve the desired drainage and flushing. 
     Referring to  FIG. 8 , for purpose of illustration and not limitation, the housing  80  can be sized to fit within a wearable component  90 , such as a belt-mounted pouch  91 . The belt  92  can be adjustable and can make it possible for the patient to carry system  100  with relative ease. The pouch  91  can be designed to fit the housing  80  and can include holes or slots such that the flush tube  51  and waste tube  50  can extend through the pouch  91 . Two external containers  93 ,  94  can be available in assorted sizes which can be attached via holsters directly to the belt, or into built-in pockets in the pouch  91 . The external containers  93 ,  94  can hold the flush material container  71 ,—and the waste collection container  70 , respectively. Although a particular wearable component is described, any suitable wearable component can be used. 
     In nominal operation, the catheter  10  can be delivered to the drainage site  2 . Instructions can be provided from the microcontroller  61 , via the motor driver  62 , to operate drain pump  30  to engage the drain tube  50  and to withdraw fluid from the drainage site through the wall holes  18 , through the drain lumen  15 , through the drain tube  50  and into the waste collection container  70  (also referred to as the drain line). Unidirectional (e.g., duckbill) valves can be used within the various elements of the drain line and/or at the joints, to prevent backflow and/or leakage of waste fluid. During draining, the pressure sensor  66  can continuously (or intermittently) measure the pressure in the drain tube  50  and can provide a continuous voltage to the microcontroller  61 . An average value can be taken over a buffer, for example, 10 pressure sensor measurements at approximately 1000 Hz. If a clog forms in the drain path (i.e., in the wall holes  18 , drain lumen  15 , or drain tube  50 ) the average pressure value can rise above a threshold. The threshold can be, for example, a user defined threshold. The system  100  can recognize that the increase in average pressure indicates a clog and a flush operation can be initiated. For example, the microcontroller  61  can send a signal, via motor driver  62 , to stop drain pump  30 . The microcontroller  61  can send a signal, via motor driver  62 , to start or increase flush pump  40  to pump the flush fluid from the flush material container  71 , through flush tube  51 , through flush lumen  16 , and through septal holes  17  (also referred to as the flush line). Additionally or alternatively, the microcontroller  61  can send a signal, via motor driver  62 , to reverse direction of the drain pump  30 . These actions can flush clogs that can form in the wall holes  18 , the drain lumen  15 , and/or drain tube  50 . The microcontroller  61  can control the rate of reverse flow in the drain line, for example, the flush volume can be programmed to be equivalent to the length of the drain lumen  15  and the drain tube  50 . This can prevent reintroducing existing waste material into the body that has been residing in the waste collection container  70 . After the flush operation is performed, the microcontroller  61  send signals, via motor driver  62 , to stop the operation of the flush pump  40  and to resume operation of the drain pump  30  to resume the draining process. Another measurement buffer can be used to prevent multiple flushes in a short duration while the pressure readings stabilize. In system  100   a  of FIG.  1 B, the microcontroller  61  can further control syringe  55  (or third pump) for delivery of additional solutions (e.g., sclerosant/drugs) into the flush tube  51 , into the flush line. 
     The remote device  67  can communicate with the transmitter  64  via a wireless transmission, such as a Bluetooth connection. For example, an Adafruit Bluefruit library can be used. A companion application (for example for use on an android operating system) can be developed in Java using Android Studio. The application can allow for Bluetooth connection to the microcontroller  65  (via the transmitter  64 ), which can enable different device settings that are optimized for the patient or medical condition settings to be selected and customized by a user (for example a clinician) on the application. For example, pump speeds, flush frequency, and flush volume can be adjusted using the application. Preset device configurations and settings for different medical conditions, tubing diameters, and catheter dimensions can be designated in the application inputted to improve ease of use and specificity. Additionally, schedules can be programmed by the user to control flush frequency, which can periodically flush the catheter  10  even if no clog is detected. The application also provides access to manual pump actions without necessitating the detection of a clog, such as flushing the system or reversing the flow upon selection in the application. The application can be controlled via a graphical user interface  68  ( FIGS. 9A-C ) or alternatively with physical controls (e.g. touchscreen) integrated with hardware. 
     Statistics and information can be collected and stored within the controller  60 . For example, biometrics and fluid drainage statistics (e.g., abscess volume drained, pressure generated during aspiration) can be collected and stored. The fluid drainage statistics can be used to notify users via the application when the waste collection container or flush material container is full or empty, respectively, and needs to be replaced. The controller  60  can be reset before each use. Algorithms can be performed on the microcontroller  65 , such as regression equations to calculate how much abscess volume has been drained using the pump speed and duration. The information can be transferred to the remote device  67  (e.g., via Bluetooth, Wi-Fi, cellular network, or radio frequency) and accessed by a user. The information can then be used for further diagnosis and additional and/or new instructions can be provided via the remote device  67 . For example, a slow and consistent drop in change in pressure can indicate that the abscess is collapsed or healed, while a sudden increase in change in pressure can indicate a clog (e.g., a fistula) may be forming or a catheter malfunction. Accordingly, an alert can be provided to a health care provider. 
     Additionally or alternatively, additional programmable features can be provided. For example, simultaneous pump function in real time, alternating function, reversal of pump functions, changing high/low pressure settings, sensor thresholds, can allow customization of pump behavior and settings. Aspiration/flush settings can be configured to automatically adjust/adapt to the mechanical properties of the waste fluid, occlusive luminal debris, and transduced pressure within the drainage site  2 . For example, the system can operate differently depending on the fluid to be drained, including air (pneumothorax), thin serous fluid (e.g., seroma, urine, ascites, pleural fluid, cysts), intermediate viscosity fluid (e.g., pus from abscess/empyema, non-infected bile, infected urine), and thick viscosity fluid (e.g., infected bile, liquefying hematoma, superinfected necrotic tissue, pancreatic pseudocyst, ruptured bowel contents). For example, pressurized pulsed sterile saline lavage can be used to irrigate a complex collection and liquefy its contents. 
     Additionally or alternatively, an integrated suite of patient biometric sensors (e.g., body temperature, heart rate, blood pressure, glucose level, hydrations status, or other biometric information) can be provided and can further influence system function. Real time data can be transmitted to a HIPAA secure web site (in addition or as an alternative to the remote device  67 ), that health care provides can monitor and that can provide alter notifications for significant changes in health status. For example, rate of change in fluid flow rate, total aspirated fluid volume/time, pressure within the catheter  10  and/or body cavity can be monitored and transmitted. Slow and progressive decrease in daily fluid output can indicate medical outcomes for the patient, such as resolution of abscess, resolution of pneumothorax without further air leak allowing for thoracostomy tube removal, patency of cystic duct allowing for cholecystostomy tube removal, patency of ureter allowing for PCN/PCNU removal. Rapid rise in body cavity pressure and resistance to flow can indicate hemorrhage. Rapid drop in body cavity pressure can indicate fistula formation. Biofeedback data can be used in conjunction with artificial intelligence and machine learning techniques to better predict and manage drain function for particular types of fluid collections, anticipated resolution of drainage, and patient health risk level. Although particular examples of data and methods of storage, transmitting, and using the data are described, any suitable data can be measured, stored, transmitted, or relied upon. 
     In accordance with the disclosed subject matter, pre-filled cartridges including chemical/enzymatic agents which can be injected into the flush line to dissolve intraluminal debris and/or antimicrobial medications can be provided. For example, one or more of tissue plasminogen activator (tPA), donase, collagenase, sterile weak acid solutions, or anti-bacterial/anti-fungal drugs can be provided. Additionally or alternatively, catheter vibration via a high frequency oscillator attached to the catheter  10 , embedded piezoelectric crystals for sonolysis, and/or other mechanisms can be used to maintain luminal patency. Integrated bioagent assays can be provided to determine the specific chemical composition of the waste fluid being removed. 
     Multiplex System with One or More Catheters and/or One or More Pumps 
     In accordance with the disclosed subject matter, a plurality of catheters  10  can be provided to a single patient, and one or more control systems (for example, a single CPU) can manage each catheter  10 . For example, a patient can receive a plurality of drainage catheters and a single central receiver can manage and/or coordinate the variable functions of each drainage catheter  10  (e.g., monitor for blockage, determine when to flush, monitor patient conditions). Additionally, systems can be modularly stacked, assigning one system to each fluid collection, which can minimize ergonomic burden on the patient, and can facilitate management. 
     Referring to  FIG. 10 , an individual patient with multiple separate abscesses  200 A,  200 B or a single multiloculated abscess, may require insertion of multiple drainage catheters  10 A,  10 B for adequate fluid evacuation. When the system is used for treating multiple separate abscesses, or a single multiloculated abscess, the system can be multiplexed to allow for either simultaneous suction and flushing of multiple catheters, or alternating drainage that switches between catheters. This multiplicity function can allow a single system to automatically control multiple drainage and/or feeding catheters in an individual patient via its controller logic, or add more pumps to the system in a modular fashion. For example, valve  103 , illustrated as a three-way stopcock between catheters  10 A an  10 B, can alternate drainage between two or more catheters draining multiple abscesses or a single complex abscess. The valve  103  can switch between a first and second state. In the first state as shown in  FIG. 10 , fluid is in communication from the first abscess  200 A across the valve  103  to the waste collection container  70 . In the first state waste can be removed from the first abscess  200 A, but not the second abscess  200 B. In a second state (not shown), fluid is in communication from the second abscess  200 B across the valve  103  to the waste collection container  70 . In the second state waste can be moved from the second abscess  200 B, but not the first abscess  200 A. Additionally or alternatively, the valve  103  is operated automatically by the controller  60 . 
     In accordance with the disclosed subject matter, a plurality of pumps and/or valves can be regulated by a central control unit. For example, multiple drain and flush pumps can be multiplexed to allow for either simultaneous suction and flushing of multiple catheters, or alternating drainage that switches between catheters. Alternatively or additionally, multiple valves can be switched under the control of the central control unit. The central control unit regulates the action of the multiple pumps and/or valves. 
     Regarding the plurality of pumps, multiple pumps can be plugged into a central control unit, which can then power and individually control each modular pump. Referring to  FIG. 11 , the central control unit  101  acts as a hub, which provides power and coordinates the actions of each individual pump ( 102   a ,  102   b ,  102   c , 102   d ). Individual pumps can be identified by unique numerical designations to ensure that the correct individual pump is programmed accordingly and that the correct line (either serving as suction or flush) is secured to the particular individual pump. Each individual pump can be attached to either the waste collection container  70 , or the flush material container  71  depending on its role. The central controller unit  101  allows the individual pumps to be programmed independently. Individual pumps (e.g.,  102   a ,  102   b ) can be plugged into the central control unit  101  to receive power and communication via direct connection. Additionally, individual pumps (e.g.,  102   c ,  102   d ) can be plugged into pumps  102   a  or  102   b  to receive power and communications passed through another pump. Additional pumps could be added in accordance with the disclosed subject matter. For example, when adding two additional drainage catheters, up to four individual pumps can be added to the system. 
     Regarding the plurality of valves, additional valves can be placed between a pump and the catheter. These plurality of valves can be regulated by the control unit  101 , and the plurality of valves can switch between two or more different states to service two or more separate catheters. Depending on the position of the valve, fluid can either be permitted or prevented from flowing across the valve, thus allowing for the variable application of suction or flush to an individual catheter. Referring back to  FIG. 10 , for purpose of illustration and not limitation, draining the first abscess  200 A using suction generated by peristaltic pump  102 , the valve  103  can switch between two states dictated by the control unit  101 . For example, switching valve  103  can alternate between the first catheter  10 A and second catheter  10 B placed in the first and second abscesses  200 A,  200 B, respectively. Alternatively or additionally, the peristaltic pump  102  can alternate pumping with periodic flushing, or flush on demand if a clogged state has been detected in the line. 
     Experimental Results: Effects of Periodic Flushing on Suction Performance 
     In accordance with the disclosed subject matter, drainage performance of the system disclosed herein using three different suction conditions was compared. Catheter  10  having flush lumen  16 , drain lumen  15 , and septal holes  17  for flushing external drainage wall holes (e.g.,  18 A-D) from across the septum  14  was used. Flushing across septum  14  can dislodge debris obstructing the at least one external drainage wall hole  18 A-D and locally dilute abscess material to maintain luminal patency of the catheter  10 . The catheter as embodied herein was tested using three different suction conditions: (1) suction provided by a Uresil accordion suction bulb, (2) suction only from a peristaltic pump, and (3) suction with periodic flushing from a peristaltic pump. An abscess analog composed of fruit blended in dairy was used. Under condition (3), when flushing was provided in addition to the suction, 10 mL of water was flushed through the catheter over an 18 second period every 2 minutes by a second peristaltic pump. Furthermore, the disclosed catheter was tested with water under the three different suction conditions as a control. All three suction conditions drained 100 mL (100 g) of water in under 5 minutes (data not shown). 
     Referring to  FIG. 12 , the results of suction over 20 minutes through the draining catheter as disclosed herein using the three different suction conditions is shown. Using the catheter as disclosed herein, after 20 minutes of draining the abscess analog, the Uresil accordion bulb removed 4.0+/−2.1 g of material, the peristaltic pump without flushing removed 61.0+/−6.3 g of material, and the peristaltic pump with periodic flushing removed 81.4+/−3.8 g of material. The peristaltic pump drained approximately 15× the abscess material over the first twenty minutes compared to the accordion bulb. Periodic flushing resulted in a 33% improvement over the same time frame using the same modality of suction. When using the Uresil accordion bulb suction and peristaltic suction alone (i.e., without flushing), rapid obstruction of the four drainage holes was observed within this time frame, and subsequent priming of the accordion bulb (data not shown) had little to no effect. If suction power was to remain insufficient to pull the material through the four 2 mm diameter drainage holes, the catheter would remain obstructed and drainage would cease or be significantly diminished unless cleared via flushing. 
     Further referring to  FIG. 12 , standard error is shown in the shaded regions and average mass drained is shown for each of the three suction conditions. Periodic flushing can clear obstructions from the external drainage holes while locally diluting viscous material. In current medical practice, flushing is performed manually and infrequently (e.g., once every 8 hrs). Increasing manual periodic flushing is not practical in the clinical setting. However, automated periodic flushing of the external drainage holes using a multi lumen catheter with septal holes, as demonstrated here, can improve drainage at equivalent suction pressures. 
     Computational Fluid Dynamics (CFD) Analysis and Results: Catheter Structure Evaluation 
     In accordance with the disclosed subject matter, computational fluid dynamics (CFD) analysis of the disclosed catheter was used to evaluate different catheter structures without the need for physical prototypes. CFD can determine parameters that evenly distribute the flush flow profile throughout the external drainage wall holes. As blockages can occur irregularly across the catheter external draining or septal holes, it is important to flush uniformly throughout the length of the catheter to minimize the probability of occlusions leading to catheter failure. 
     For example, through iterative, simulation prototyping, different catheters were quickly modeled and evaluated for flushing performance as measured by flow rates through the catheter external drainage and septal holes. All 3D models of the dual-lumen catheter were created using 3D parametric modeling software, Fusion 360 (Autodesk, San Rafael, Calif., United States)). Using geometric modifiers, structural features of the catheter were parametrically manipulated to generate the catheter structural concepts. Referring to  FIG. 13 , the original baseline catheter structure (Concept A) consisted of a dual lumen channel with four external drainage wall holes  18   a - 18   d  (2 mm diameter) spaced 13 mm apart, and 4 septal holes  17   a - 17   d  (1 mm diameter) that were equally sized and aligned with wall holes  18   a - 18   d . The distal tip of catheter  10  can be tapered, with a small opening that mimics the guide hole commonly found in multipurpose drainage catheters. The distal opening  21  allows for direct communication with the waste lumen  15 , and indirect communication to the flush lumen  16 . In the CFD analysis, fluid flow through distal opening  21  was ignored as the size and location only marginally impacted the fluid dynamics. 
     Again referring to  FIG. 1A , catheter  10  has two reversible pumps attached to both the flush and waste lumen which can be independently controlled. The typical flushing action can be coupled with a brief reversal of the suction pump at an equivalent fluid velocity to generate greater positive flow, and hence pressure, at the wall holes  18   a - 18   d  to clear debris. Regarding  FIG. 15 , the baseline catheter Concept A structure was used to compare various flush pumping and/or suction pumping techniques. Using CFD, a saline flush only, and a simultaneous saline flush and suction pump reversal action was performed, and CFD differences were quantified. Additionally, the simultaneous flush and suction pump reversal was compared to a saline flush only technique at twice the flush velocity to measure how average flow rates at the wall holes  18   a - 18   d  compared when the flush fluid flow is (a) either split across both waste  15  and flush 16 lumens, or (b) only the flush lumen  16 . Running both the flush pump and suction pump simultaneously was used to analyze all ensuing structural modifications. 
     Subsequent structural modifications to the catheter geometry improved flushing performance. These structural modifications included alignment of septal holes to the distal holes, varying septal hole diameter, and cross-sectional area of waste and flush lumens. All concepts were compared to the baseline catheter structure (Concept A) to assess increases/decreases in wall hole fluid velocity during flushing. Table 1 summarizes the various catheter structures tested. 
     Regarding Concepts B and C, the location of septal holes  17   a - 17   d  were staggered with respect to the wall holes  18   a - 18   d  along the catheter. It was theorized that fluid interference at the junctions between the flush liquid and reversal from the waste lumen could be compensated through alternative positioning, improving wall hole flow. Regarding Concepts D and E, the diameters of septal holes  17   a - 17   d  were varied such that the septal holes diameters increased from septal hole  17   d  by the proximal end portion  12 , towards septal hole  17   a  by the distal end portion  13 . Furthermore, in Concepts F and G the waste lumen to flush lumen volume ratio was increased to investigate if the augmented venturi effect could improve flushing. Catheter Concept A-G structures are provided in Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Summary of Structural Changes Relative to Baseline Catheter 
               
               
                 (Concept A). CFD analysis proceeded for Catheters Concepts 
               
               
                 B-G simulating changes in volume ration, septal hole 
               
               
                 diameter, and septal hole location. 
               
            
           
           
               
               
               
               
            
               
                   
                 Volume Ratio 
                 Septal Hole 
                   
               
               
                   
                 (Waste 
                 Diameter (mm) 
               
               
                   
                 Lumen:flush 
                 (17d, 17c, 
               
               
                 Concept 
                 Lumen) 
                 17b, 17a) 
                 Septal Hole Location 
               
               
                   
               
               
                 A (Baseline 
                 50:50 
                 1, 1, 1, 1 
                 Aligned with outlet holes 
               
               
                 Catheter) 
               
               
                 B 
                 50:50 
                 1, 1, 1, 1 
                 Septal holes shifted 
               
               
                   
                   
                   
                 proximally 1 mm 
               
               
                 C 
                 50:50 
                 1, 1, 1, 1 
                 Septal holes shifted 
               
               
                   
                   
                   
                 proximally 6.5 mm 
               
               
                 D 
                 50:50 
                 1, 1.5, 2, 3 
                 Aligned with outlet holes 
               
               
                 E 
                 50:50 
                 0.5, 0.75, 
                 Aligned with outlet holes 
               
               
                   
                   
                 1, 1.5 
               
               
                 F 
                 60:40 
                 1, 1, 1, 1 
                 Aligned with outlet holes 
               
               
                 G 
                 80:20 
                 1, 1, 1, 1 
                 Aligned with outlet holes 
               
               
                   
               
            
           
         
       
     
     CFD Methods and Procedure 
     To perform CFD analysis, the 3D CAD models of the proposed catheter designs were imported into OpenFOAM CFD software (The OpenFOAM Foundation, United Kingdom). In OpenFOAM, finite element models were generated for catheter Concepts A-G at approximately a 5:1 scale. Scaling models is common approach to reducing the simulation complexity and decreasing time to complete CFD simulations. The fluid dynamics at the flushing phase of the device was visualized and quantified across all catheter design concepts. In OpenFOAM, a simple steady-state fluid flow simulation was performed across catheter Concepts A-G. Regarding  FIG. 14 , a finite volume method was applied to solve basic Navier-Stokes equations and show streamlines. In these simulations only conservation of mass and momentum equations were applicable as no heat transfer was assumed. Homogenous liquid properties for water were used in both inlets, assuming an incompressible liquid flow. The flush inlet velocity was defined at 1.5 cm/s for the flush flow. When examining the flush and suction pump reversal, the flush inlet velocity of 1.5 cm/s was duplicated at the waste lumen inlet. Catheter performance between design concepts was assessed by measuring the steady state fluid velocities at the outlets during flushing. Specifically, the average fluid flow velocity across the surface area of the external drainage wall holes  18   a - 18   d  were calculated. 
     Iterative CFD Comparative Analysis: Saline Flush Simulations 
     Regarding  FIG. 15  and corresponding Table 2, in a saline flush simulation, there was a substantial increase in all wall hole velocities ( 18   a - 18   d ) for simultaneous flush and suction pump reversal when compared to flushing only. Fluid flow increased by 147%, 102%, 79%, and 82% for wall holes  18   d ,  18   c ,  18   b , and  18   a , respectively. The flush and suction pump reversal closely approximated the flow velocity observed during a saline flush at twice the initial fluid velocity. The decrements between these two conditions were less than 16% across all wall holes. Thus, all subsequent CFD design evaluations would only use the saline flush and waste flow removal mechanism. Table 2 illustrates the results from the baseline catheter (Concept A) used for the three tests in  FIG. 15 . Regarding Table 2, the baseline catheter was analyzed with a saline flush only, saline flush and simultaneous suction (i.e., fluid flow reversal) in the drainage lumen, and saline flush only at twice the velocity. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 CFD results for saline flush and/or simultaneous pump 
               
               
                 simulations of Baseline Catheter (Concept A). 
               
            
           
           
               
               
               
               
               
            
               
                 Baseline Catheter 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
               
               
                 (Concept A) 
                 18d (cm/s) 
                 18c (cm/s) 
                 18b (cm/s) 
                 18a (cm/s) 
               
               
                   
               
               
                 Saline flush only 
                 0.38 
                 0.54 
                 0.72 
                 0.78 
               
               
                 Saline flush and 
                 0.94 
                 1.09 
                 1.29 
                 1.42 
               
               
                 suction pump reversal 
               
               
                 Saline flush only 
                 1.02 
                 1.26 
                 1.5 
                 1.57 
               
               
                 at twice velocity 
               
               
                   
               
            
           
         
       
     
     Iterative CFD Comparative Analysis: Septal Hole Shifting (Concepts B and C) 
     Regarding  FIG. 16  and corresponding Table 3, septal holes  17   a - 17   d  were shifted towards proximal end portion  12  and the catheter performance was reviewed. Shifting septal holes  17   a - 17   d  1.0 mm towards proximal end portion  12  in Catheter Concept B, can increase fluid velocities at all outlet wall holes  18   a - 18   d  in comparison to the baseline catheter Concept A. Shifting septal holes  17   a - 17   d  6.5 mm towards proximal end portion  12  in Catheter Concept C can increase fluid velocity in proximal most wall holes  18   d  and  18   c , but decrease fluid velocity in distal most wall holes  18   b  and  18   a . Regarding Table 3, the fluid velocity variations across outlet wall holes  18   d ,  18   c ,  18   b , and  18   a  were +43%, +17%, −2%, and −13%, respectively. The largest fluid velocity increase in Concept B was observed in outlet  18   d  with a 15% increase. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Concept Catheter Structures B and C wall hole flow velocities 
               
               
                 compared to Baseline Catheter (Concept A): Changes in fluid 
               
               
                 velocity at the wall holes 18a-18d as a function of shifting 
               
               
                 septal holes (e.g., 17a-17d; FIG. 13) towards proximal end 
               
               
                 portion 12 compared to the baseline catheter Concept A. 
               
            
           
           
               
               
               
               
               
            
               
                 Catheter Design 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
               
               
                 Concept 
                 18d (cm/s) 
                 18c (cm/s) 
                 18b (cm/s) 
                 18a (cm/s) 
               
               
                   
               
               
                 Concept A: 
                 0.94 
                 1.09 
                 1.29 
                 1.42 
               
               
                 Baseline Catheter 
               
               
                 Concept B: Septal 
                 1.08 
                 1.18 
                 1.38 
                 1.43 
               
               
                 Holes Shifted 
               
               
                 Proxmally 1 mm 
               
               
                 Concept C: Septal 
                 1.34 
                 1.28 
                 1.27 
                 1.23 
               
               
                 Holes Shifted 
               
               
                 Proxmally 6.5 mm 
               
               
                   
               
            
           
         
       
     
     Iterative CFD Comparative Analysis: Septal Hole Diameter Modifications (Concepts D and E) 
     Regarding  FIG. 17  and corresponding Table 4, in Concepts D and E, the septal holes  17   a - 17   d  had their diameters modified and the CFD results were evaluated. In catheter Concept D, the septal hole diameters of septal holes  17   d ,  17   c ,  17   b , and  17   a  were changed from 1 mm for all septal holes in the baseline catheter, to 1, 1.5, 2, and 3 mm, respectively. Compared to baseline catheter Concept A, the fluid velocity at proximal most wall holes  18   d  and  18   c  of catheter Concept D increased, but the fluid velocity at distal most wall holes  18   b  and  18   a  decreased. In catheter Concept E, the septal hole diameters of septal holes  17   d ,  17   c ,  17   b , and  17   a  were changed to 0.5, 0.75, 1, and 1.5 mm, respectively. In Concept E, fluid velocity decreases were observed at proximal most wall holes  18   d  (41%) and  18   c  (16%), but a substantial increase in fluid velocity was observed at wall hole  18   a  (37%). As noted above, during drainage, wall holes  18  can become clogged. Wall holes towards the distal end portion  13  of the catheter can be more susceptible to clogging than wall holes  18  towards the proximal end portion  12  of the catheter. Accordingly, septal hole diameters can be specified to produce an increased fluid velocity towards the distal end portion  13  of the catheter. Increasing fluid velocity at the septal holes  17  and/or of the wall holes  18  can help dislodge clogged material and maintain catheter patency. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Concept Catheter Structures D and E with changes in 
               
               
                 septal hole diameters. Comparison of wall hole flow 
               
               
                 velocities in Concepts D and E with Baseline Catheter 
               
               
                 (Concept A) having equal sized septal holes. 
               
            
           
           
               
               
               
               
               
            
               
                 Catheter Design 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
               
               
                 Concept 
                 18d (cm/s) 
                 18c (cm/s) 
                 18b (cm/s) 
                 18a (cm/s) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Concept A: 
                 0.94 
                 1.09 
                 1.29 
                 1.42 
               
               
                 Baseline Catheter 
               
               
                 Concept D: 
                 0.95 
                 1.1 
                 1.25 
                 1.36 
               
               
                 increased Septal 
               
               
                 Hole Diameter 
               
               
                 (1-3 mm) 
               
               
                 Concept E: 
                 0.55 
                 0.92 
                 1.31 
                 1.94 
               
               
                 Increased Septal 
               
               
                 Hole Diameter 
               
               
                 (0.5-1 mm) 
               
               
                   
               
            
           
         
       
     
     Iterative CFD Comparative Analysis: Changing Drain and Flush Lumen Volumetric Properties (Concepts F and G) 
     Regarding  FIG. 18  and corresponding Table 5, in catheter Concepts F and G a CFD comparative analysis of structures incorporating different volumetric proportions between the waste lumen  15  (i.e., drain lumen) and flush lumen  16  was performed. In the 60:40 drain-to-flush proportion structure (Concept F), there were minimal differences in fluid velocity across all wall holes. Only wall hole  18   b  fluctuated by 0.01 cm/s. However, the 80:20 drain-to-flush proportion structure (Concept G) showed larger effects on the wall hole fluid velocity. Compared to the baseline catheter, wall holes  18   d  and  18   c  in Concept G decreased by 21% and 7%, respectively, while wall holes  18   b  and  18   a  increased by 2% and 13%, respectively. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Concept Catheter Structures F and G wall hole flow velocities 
               
               
                 compared to Baseline Catheter (Concept A) with 50:50 Drain:Flush 
               
               
                 lumen proportions: Changes in septal hole diameter in Concepts 
               
               
                 F-G compared to the baseline catheter Concept A with equal 
               
               
                 sized drain and flush lumens. 
               
            
           
           
               
               
               
               
               
            
               
                 Catheter Design 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
               
               
                 Concept 
                 18d (cm/s) 
                 18c (cm/s) 
                 18b (cm/s) 
                 18a (cm/s) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Concept A: 
                 0.94 
                 1.09 
                 1.29 
                 1.42 
               
               
                 Baseline Catheter 
               
               
                 Concept F: 60:40 
                 0.94 
                 1.09 
                 1.28 
                 1.42 
               
               
                 Drain:Flush 
               
               
                 Lumen Proportions 
               
               
                 Concept G: 80:20 
                 0.74 
                 1.01 
                 1.32 
                 1.6 
               
               
                 Drain:Flush 
               
               
                 Lumen Proportions 
               
               
                   
               
            
           
         
       
     
     Iterative CFD Comparative Analysis: Adding Outward Flush Hole (Concept H) Reduces Wall Hole Flow Velocities 
     Regarding  FIG. 19  and corresponding Table 6, a CFD comparative analysis of Catheter Concept H including both septal holes  17   a - 17   d  and outward flush holes  22   a - 22   d  was performed using flushing only. It was hypothesized that including outward flush holes  22   a - 22   d  would allow for more direct irrigation of an abscess cavity. However, CFD analysis of Concept H having outward flush holes  22   a - 22   d  demonstrates a substantial decrease in flush fluid flow velocity across wall holes  18   a - 18   d . In particular, there was over 40% reduction in the fluid flow velocity at wall holes  18   a - 18   d  in Concept H when compared to Concept A having septal flush holes (but no outward flush holes  22   a - 22   d ). Thus, including inward and outward flush holes can result in lower fluid velocity through wall holes  18   a - 18   d  and an increased likelihood of obstructive debris at drainage wall holes  18   a - 18   d . 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Concept Catheter Structure H with outward flush holes compared 
               
               
                 to Baseline Catheter (Concept A): Adding outward flush holes 
               
               
                 22a-22d reduced fluid flow at the drainage wall holes 18a-18d. 
               
            
           
           
               
               
               
               
               
            
               
                 Catheter Design 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
               
               
                 Concept 
                 18d (cm/s) 
                 18c (cm/s) 
                 18b (cm/s) 
                 18a (cm/s) 
               
               
                   
               
               
                 Concept A: 
                 0.38 
                 0.54 
                 0.72 
                 0.78 
               
               
                 Baseline Catheter 
               
               
                 Concept H: Septal and 
                 0.12 
                 0.24 
                 0.38 
                 0.48 
               
               
                 Outward Flush Holes 
               
               
                   
               
            
           
         
       
     
     Regarding  FIG. 20  and corresponding Table 7, a CFD comparative analysis of Catheter Concept I including a distal end hole was performed. It was hypothesized that the fluid flow from the distal end hole was negligible. CFD analysis of Concept I having a distal end hole found minimal, proportional decreases in fluid velocity across wall holes  18   a - 18   d  in a comparison between the baseline catheter Concept A and Concept I have a distal end hole. Thus, the impact of a distal end hole of wall hole fluid velocities and the corresponding CFD analysis can be considered negligible. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Concept Catheter Structure I with distal end hole 
               
               
                 has negligible impact on wall hole flow velocities. 
               
            
           
           
               
               
               
               
               
            
               
                 Catheter Design 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
                 Wall Hole 
               
               
                 Concept 
                 18d (cm/s) 
                 18c (cm/s) 
                 18b (cm/s) 
                 18a (cm/s) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Concept A: 
                 0.94 
                 1.09 
                 1.28 
                 1.45 
               
               
                 Baseline Catheter 
               
               
                 Distal End 
               
               
                 Hole Excluded 
               
               
                 Concept I: 
                 0.91 
                 1.03 
                 1.2 
                 1.35 
               
               
                 Distal End Hole 
               
               
                 Included 
               
               
                   
               
            
           
         
       
     
     Discussion of CFD Results 
     Using both parametric CAD modeling and CFD software, catheter structural concepts can be rapidly analyzed and iterated using physics-based simulations. Various concepts can be tested with the goal to maximize fluid velocities evenly across all wall holes  18   a - 18   d  and CFD result comparisons can be performed. 
     By including a brief suction pump reversal during the flushing action, this structural change can lead to sizable fluid velocity increases across all wall holes in comparison to the flush only action. Although wall hole  18   d  showed the largest velocity increase (147%), all other wall hole fluid velocities nearly doubled, when compared to the flush only condition. The flush with simultaneous suction pump reversal condition can be nearly as effective as a hypothetical saline flush at 2 times the initial velocity, with minimal fluid velocity loss (less than 17%) due to fluid interferences at lumen junctions. Thus, this concept can be adopted into the final structure and applied to all ensuring CFD simulations. 
     It was observed that many catheter internal structural modifications could improve overall fluid flow, but only if parameters were crafted carefully. In suboptimal designs such as shifting the holes proximally by 6.5 mm or increasing septal hole diameters to 0.5-1.5 mm, the resulting fluid velocity at the wall holes would decrease in some wall holes, but then increase in the remaining wall holes. These structural changes can be diverting only fluid flow across wall holes, without reducing fluid interferences, substantially. In contrast, shifting the septal holes by 1 mm improved the velocities across all wall holes. These structural changes redirected the fluid flow along more optimal pathways so that fluid interactions were minimized. Enlarging the septal hole along the septum mainly increased the fluid velocity in the most-distal holes, while shifting the septal holes proximally mainly improved fluid velocity at the most proximal wall holes. Furthermore, Catheter Concept G with the 80:20 drain-to-flush lumen proportion confers the benefit of drainage during nominal abscess waste removal operations. Flushing strength would be marginally affected as wall hole  18   d  fluid velocity decreased by 0.20 m/s (21%) and fluid velocity gains were observed in wall hole  18   a  by 0.18 m/s (13%). The CFD analysis indicates that internal catheter structural changes can lead to noticeable fluid dynamics changes in a dual-lumen catheter during flushing. 
     Caveats and limitations to CFD analysis includes assuming fluids are homogenous, whereas in a clinical use case, the waste lumen may contain material that is more viscous. Furthermore, the transient fluid interactions at the startup of the were largely ignored in this steady state analysis. It was theorized that the fast fluid flow velocities would achieve steady state flow quickly inside the relatively small volume of the catheter. Limitations with the steady state CFD analysis were supplemented with physical benchtop testing. Although these limitations can affect the fidelity of the CFD results, the results still provided reasonable and practical knowledge during the virtual, rapid prototyping phase without the need to build numerous costly prototypes. 
     Additional operational states and structural parameters can further improve flushing. For example, the strength of flush and/or suction pumps can be adjusted to manipulate fluid velocity profiles. During the CFD analysis, only the flushing phase of the catheter was analyzed. However, the catheter can perform several different actions such as performing waste lumen drainage while a flush action is simultaneously occurring to cleanse the waste lumen. 
     Methods for Percutaneous Drainage 
       FIG. 21  illustrates an example method  1000  for percutaneous drainage of a drainage site. The method  1000  can begin at step  1100 , where the method includes inserting a catheter into the drainage site. The catheter including a catheter wall extending from a proximal end portion of the catheter to a distal end portion of the catheter, the distal end portion of the catheter configured for placement within the drainage site; a septum disposed within the catheter wall and extending from a proximal end portion of the catheter to a distal end portion of the catheter; a drain lumen defined by a first portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter; and a flush lumen defined by a second portion of the catheter wall and the septum, and extending from the proximal end portion of the catheter to the distal end portion of the catheter, wherein the flush lumen is separated from the drain lumen by the septum. The septum has at least one septal hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen and the flush lumen are in communication via the at least one septal hole; and wherein the catheter wall has at least one wall hole disposed therein proximate to the distal end portion of the catheter such that the drain lumen is in communication with the drainage site when the distal end portion is placed within the drainage site. At step  1200  the method can include withdrawing fluid from the drainage site via the drain lumen. At step  1300  the method can include identifying an occlusion in the drain lumen. At step  1400  the method can include flushing a flush fluid through the flush lumen and into the drain lumen via the at least one septal hole and thereby removing the occlusion. In accordance with the disclosed subject matter, the method can repeat one or more steps of the method of  FIG. 21 , where appropriate. Although this disclosure describes and illustrates particular steps of the method of  FIG. 21  as occurring in a particular order, this disclosure contemplates any suitable steps of the method of  FIG. 21  occurring in any suitable order. Moreover, although this disclosure describes and illustrates an example method for percutaneous drainage of a drainage site including the particular steps of the method of  FIG. 21 , this disclosure contemplates any suitable method for percutaneous drainage of a drainage site including any suitable steps, which can include all, some, or none of the steps of the method of  FIG. 21 , where appropriate. Furthermore, although this disclosure describes and illustrates particular components, devices, or systems carrying out particular steps of the method of  FIG. 21 , this disclosure contemplates any suitable combination of any suitable components, devices, or systems carrying out any suitable steps of the method of  FIG. 21 . 
     Where system  100  is used for percutaneous thoracostomy, the sensor/microcontroller system can be further programmed to detect the presence, persistence, and/or resolution of pneumothorax, air leak, and/or bronchopleural fistula. Where system  100  is used for percutaneous chemical ablation and/or sclerosis of cystic lesions, recurrent fluid collections (such as lymphoceles and other disorders of the lymphatic system), and/or hollow viscera (such as gallbladder in candidates deemed unsuitable for cholecystectomy), the system can monitor volume of injected sclerosant/polymer glue, dwell time, irrigation, simultaneous or delayed aspiration, repeated cycles. In such use, the catheter  10  can be provided with side holes along both of its outer walls  11  and no septal holes  17 . Where the system is used for percutaneous esophagostomy gastrostomy, gastrojejunostomy, jejunostomy, and/or cecostomy (i.e., the alimentary/digestive tract), the system can include programmable tube feeding setting for patient-specific nutritional needs, and tube flushing settings for maintenance of luminal patency. 
     Enteral Feeding 
     Regarding  FIG. 22 , system  100 C is configured for use with enteral (e.g., gastrostomy, gastrojejunostomy, jejunostomy) feeding catheters (e.g., enteral tube  72 ). For example, indwelling percutaneous gastrostomy catheter  71  can feed the stomach with liquid nutrition formula from container  73  via peristaltic pump  102   a  instillation. A pressure sensor  75  installed along the tubing between container  73  and indwelling percutaneous gastrostomy catheter  71  enables detection of luminal occlusion due to feed concretions or other particulate matter. In the event of occlusion, control unit  60  activates a second peristaltic pump  102   b  attached to container  74  filled with sterile water or saline, thereby enabling powered flushing and restoration of tube patency. Flushing can also be regularly scheduled with preset volume and pressure for tube maintenance. Optional syringe pump  76  allows for administration of prescribed medications per the enteral tube  72 . 
     While the disclosed subject matter is described herein in terms of certain preferred embodiments for purpose of illustration and not limitation, those skilled in the art will recognize that various modifications and improvements can be made to the disclosed subject matter without departing from the scope thereof. Moreover, although individual features of one embodiment of the disclosed subject matter can be discussed herein or shown in the drawings of one embodiment and not in other embodiments, it should be readily apparent that individual features of one embodiment can be combined with one or more features of another embodiment or features from a plurality of embodiments. 
     In addition to the specific embodiments claimed below, the disclosed subject matter is also directed to other embodiments having any other possible combination of the dependent features claimed below and those disclosed above. As such, the particular features presented in the dependent claims and disclosed above can be combined with each other in other possible combinations. Thus, the foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the method and system of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Thus, it is intended that the disclosed subject matter include modifications and variations that are within the scope of the appended claims and their equivalents.