Abstract:
When a patient is fitted with an external gastrostomy connection to the stomach, ingested food can be removed through the gastrostomy connection using a pump-based or siphon-based system to achieve weight loss. The process of removing ingested food can be improved by alternating the infusion of liquid into the stomach with the removal of material from the stomach. Optionally, stomach acid may be captured and returned to the stomach. Optionally, nutritional supplements or medicines may be added to the infused liquid. Optionally, a flush mount connectorized system with a built in valve may be used to simplify the interface with the gastrostomy hardware that remains installed in the patient. Optionally, the system may be configured to disable itself from further use after a triggering event (e.g., the passage of time or a predetermined number of uses) has occurred.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application No. 60/821,333, filed Aug. 3, 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention generally relates to removing ingested material from a stomach of a patient, and the primary intended fields of the invention are facilitating weight loss and preventing weight gain. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect of the invention, food that has been ingested is removed from the patient&#39;s stomach via a gastrostomy tube using a siphon action. In another aspect of the invention, food that has been ingested is removed from the patient&#39;s stomach via a gastrostomy tube, and the removal of food is facilitated by infusing fluid into the patient&#39;s stomach via the gastrostomy tube. In another aspect of the invention, matter that has been ingested is removed from the patient&#39;s stomach via a gastrostomy tube, and stomach acid is separated from the removed matter and returned to the patient&#39;s stomach. In another aspect of the invention, matter that has been ingested is removed from the patient&#39;s stomach via a gastrostomy tube, and the system is configured to disable itself from further use after the occurrence of a triggering event (e.g., the passage of time or a predetermined number of uses). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of an embodiment of the invention for removing ingested material from a patient&#39;s stomach. 
         FIG. 2  is a schematic representation of a first embodiment for implementing the system shown in  FIG. 1 . 
         FIG. 3  is a schematic representation of a second embodiment for implementing the system shown in  FIG. 1 . 
         FIG. 4  shows a side view of a third embodiment for implementing the system depicted in  FIG. 1 . 
         FIG. 5A  shows an isometric view of the  FIG. 4  embodiment. 
         FIG. 5B  shows a front view of internal components of the  FIG. 4  embodiment. 
         FIG. 5C  shows a back view of internal components of the  FIG. 4  embodiment. 
         FIG. 6A  shows an isometric view of another embodiment for implementing the system depicted in  FIG. 1 . 
         FIG. 6B  shows a front view of internal components of the  FIG. 6A  embodiment. 
         FIG. 7A  schematically shows an embodiment of a system for removing ingested material from a stomach, filtering select gastric contents, and returning filtered fluid to the stomach. 
         FIG. 7B  schematically shows an embodiment of a system for removing ingested material from a stomach, filtering select gastric contents, and returning filtered fluid and water to the stomach. 
         FIG. 8A  shows a patient with a skin connector coupled with a gastrostomy tube that is inserted into the stomach. 
         FIG. 8B  shows a view of the skin connector prior to mating with a tube connector. 
         FIG. 8C  shows a view of the skin connector mated with a tube connector. 
         FIGS. 9A ,  9 B, and  9 C show side, top, and isometric views of a skin connector valve assembly for the embodiment shown in  FIGS. 8A-8C . 
         FIGS. 10A ,  10 B, and  10 C show side, top, and isometric views of an assembled flush skin connector for the embodiment shown in  FIGS. 8A-8C . 
         FIGS. 11A ,  11 B, and  11 C show side, top, and isometric views of a skin connector flange assembly for the embodiment shown in  FIGS. 8A-8C . 
         FIG. 12  is an exploded view of the rotational valve assembly for the embodiment shown in  FIGS. 8A-8C . 
         FIG. 13A  shows a bottom view of a tube connector assembly for the embodiment shown in  FIGS. 8A-8C . 
         FIG. 13B  shows a side view of a tube connector assembly for the embodiment shown in  FIGS. 8A-8C . 
         FIGS. 14A and 14B  show the tube connector connected to the skin connector of the embodiment shown in  FIGS. 8A-8C , in the closed and opened positions, respectively. 
         FIG. 15  shows the embodiment shown in  FIGS. 8A-8C  being used by a patient. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This application discloses methods and apparatuses for removing material from a patient. In the exemplary embodiment disclosed herein, the methods and apparatuses are used for removing ingested material from a patient&#39;s stomach in patients that have been fitted with a gastrostomy tube. Examples of suitable gastrostomy tubes are described in U.S. Patent Application Publication Nos. US 2004/0220516, US 2005/0277900 and US 2005/0283130, each of which is incorporated herein by reference. Additional gastrostomy tubes are described in U.S. Provisional Patent Application 60/806,556, which is also incorporated herein by reference. 
     The primary contemplated use for the methods and apparatuses described herein is achieving weight loss in obese or overweight people. Although the exemplary embodiments are described herein in the context of removing ingested material from a patient&#39;s stomach, the methods and apparatus can also be used for removal of a variety of fluids from a patient (with, when necessary, appropriate modifications that will be apparent to persons skilled in the relevant arts). 
       FIG. 1  shows a patient  10  that is fitted with a gastrostomy tube with a system for removing ingested material from a stomach. An example of such a gastrostomy tube  45  is shown in  FIG. 8A . The gastrostomy tube  45  interfaces with the outside world via connection  14 , so the system communicates with the gastrostomy tube  45  through that connection. The system preferably includes an assembly  16  for infusing fluid into the stomach through the connection  14  in a manner permitting the fluid to mix with the ingested material or, for use in priming the system when desired, and a drain line  18  for draining content of the stomach received from the connection  14 . 
     The drain line  18  may be in communication with the assembly  16 , as shown. In alternative embodiments (not shown), the drain line  18  may be implemented independent of the assembly  16 . For example, one line may be used to drain content of the stomach through the connection  14  and another line may infuse the fluid into the stomach through the connection. The system preferably includes a patient line  20  in communication with the assembly  16  and the connection  14  to the patient  10 , and the patient line  20  preferably has a suitable connector at its upper end that mates with the connection  14 . In alternative embodiments (not shown), the assembly  16  may be coupled directly to the external gastrostomy connection  14  without using an intermediate patient line. The assembly  16  may include a fluid source and may optionally include a valve arrangement and/or one or more pumps as described in more detail below. 
     In operation, the system is connected up to the connection  14  to remove the contents of the stomach via the connection. In some embodiments, the removal may be accomplished by pumping the stomach contents out via the connection  14 . In alternative embodiments, this removal is accomplished by setting up a siphon system so that the contents of the stomach can be siphoned out of the patient&#39;s stomach. 
     In siphon-based systems, the drain line  18  preferably has a length in excess of 25 cm in order to create a pressure differential that is sufficient to form an effective, efficient siphon that can gently and passively drain content from the stomach. However, in alternative embodiments, the drain line  18  can be of a length less than 25 cm. Note that when the patient is standing, the overall siphon system is measured from the lowest point in the tube or line that is inserted into the stomach to the end of the drain line  18 . Optionally, the siphon system may be designed to be long enough to run from the stomach of a standing patient to a position proximate to a floor-based disposal arrangement, such as a toilet or waste container. The drain line may include a siphon tube made from flat, collapsible tubing or other flexible tubing. Silicon is a suitable material for the patient line  20  and the drain line  18 . However, in alternative embodiments, the patient line  20  can be made from any material known and used in the art of tubes or any material that could be used to impart the necessary function of the patient line  20 . 
     In some situations (e.g., when the patient has drank a significant amount of liquids), an effective siphon effect can be achieved without infusing any liquids into the patient&#39;s stomach. In other situations, however, it may be necessary to add additional fluid into the patient&#39;s stomach to help start up the siphoning, so that the ingested material can be effectively removed from the patient&#39;s stomach. This may be done by having the patient drink additional fluids or by infusing additional fluid into the stomach through the connection  14 . 
     In many cases, a single siphoning operation will be insufficient to remove the desired amount of ingested material from the patient&#39;s stomach. In those cases, it is desirable to introduce additional liquid into the stomach so that one or more additional siphoning operations can be done. A preferred approach for introducing additional liquid into the stomach is by infusing the liquid into the stomach through the connection  14 . For example, after eating a meal and drinking liquids, the subject may attach the device to the connection  14 , and siphon out a large portion of the stomach contents (e.g., fluid with solid particulate, pieces, and/or chunks of food). For a typical meal, the volume of this initial siphoning operation may be on the order of 750 cc, but that number will of course vary based on the volume and characteristics of the ingested meal. Once the siphon effect stops, the subject infuses water back through the connection  14  into the stomach and then initiates another siphoning operation to remove the infused water, which will carry out additional solid food particles, pieces and/or chunks. The infusing and siphoning steps may then be repeated until the desired amount of ingested material is removed from the stomach. An example of a suitable volume for infusing into the stomach during the infusing step is 180 cc, although any other volume may be used. 
     Note that the methods described herein are preferably used to remove a significant portion of the food that the patient has ingested (e.g., between 30 and 60%, and more preferably between 40 and 50%, of the ingested food). Removing all the food that was ingested by the patient is not preferred and will usually be impractical. Examples of systems that implement both the removal of ingested material and the infusion of fluids are described below. 
       FIG. 2  schematically shows a first embodiment of a system for alternately removing ingested material from a stomach and infusing fluid into the stomach. The fluid may be any biocompatible fluid such as water or saline, and may optionally include one or more nutrients and/or medications. As shown, the assembly  16  includes a fluid source  22  and a valve arrangement  24  in communication with the fluid source  22 , the drain line  18 , and the patient line  20 . The valve arrangement  24  may include one or more valves and any type of valve, such as, but not limited to, check valves, blade occluder and diverter valves. For example, the valve arrangement  24  may be implemented using a single 3-way valve with two operating positions—one position that opens a path between the patient line  20  and the drain line  18 , and another position that opens a path between the fluid source  22  and the patient line  20 . Alternatively, the valve arrangement  24  may be implemented using two valves—a first valve used to open a path between the patient line  20  and the drain line  18  and a second check valve used to open a path between the fluid source  22  and the patient line  20  when fluid is pumped from the fluid source  22  into the patient&#39;s stomach via connection  14  (shown in  FIG. 1 ). In operation, the first valve is opened to drain the contents of the stomach. The first valve is then closed and fluid is pumped from the fluid source  22  to the patient line  20 . Optionally, the first valve may be closed automatically by the fluid when the fluid is pumped from the fluid source  22 . The first valve may then be re-opened to drain content of the stomach when fluid is no longer pumped to the patient line  20 . 
     Other embodiments may include a plurality of valves, such as shown in  FIG. 3 .  FIG. 3  schematically shows an assembly  16  having a check valve, valve A, in communication with the fluid source  22  and also with two valves, valve B and valve F. Valve B is in communication with a check valve, valve C, which is in communication with the connection  14  (shown in  FIG. 1 ) via the patient line  20 . Valve F is in communication with a check valve, valve E, which is in communication with the drain line  18 . Another valve, valve D is in communication with the patient line  20  and the drain line  18 . Valve B and valve F may be coupled, such that valve B is opened when valve F is closed, and valve F is opened when valve B is closed. In operation, valve B is opened while valve F is closed. Valve D may then be opened to drain the contents of the stomach received from the patient line  20 . Optionally, the system may be configured so that as fluid is pumped through valve B and valve C, the movement of the fluid closes valve D and permits the fluid to flow into the stomach through the patient line  20 . When fluid is no longer pumped through valves B and C, valve D may be activated automatically or manually to re-open to drain content of the stomach. When finished removing content from the stomach, valve D is closed and valve B is closed, which in turn opens valve F. The fluid may then be pumped through valve A, valve F and valve E to the drain line  18  in order to clean the drain line after use. 
     Variations on the assembly  16  shown in  FIG. 3  may be implemented using one or more pumps in communication with the valve arrangement  24 , the fluid source  22  and/or the drain line  18 . For example, a pump may be coupled between the fluid source  22  and the patient line  20  with a check valve in communication with the fluid source  22  and the pump and another check valve in communication with the pump and the patient line  20  to facilitate fluid flow to the connection  14  (shown in  FIG. 1 ). A pump may be coupled between the patient line  20  and the drain line  18  with a check valve in communication with the patient line  20  and the pump and another check valve in communication with the pump and the drain line  18 . A pump may also be provided by the squeezing of a hand, e.g., squeezing the fluid source. A combination of two or more pumps may be used, to facilitate fluid flow to the patient line  20 , to the drain line  18 , or both. For example, during operation, if the system becomes clogged with content of the stomach such that the draining and/or infusing is not functioning properly, a pump may be provided to clear the obstruction in the patient line  20  and/or the drain line  18 . Various types of pumps may also be used, such as, but not limited to, a diaphragm pump, a spring loaded piston pump, a syringe pump, a peristaltic pump, a flexible vein pump, a pneumatically actuated pump or a combination thereof. The pump(s) may be removable from the system such that a pump is only provided when necessary. 
     Referring now to  FIGS. 2 and 3 , a removable syringe may be provided at an auxiliary port  25  to provide suction for removing clogs from the patient line  20  and/or drain line  18 . Although various configurations have been discussed for the valves and pumps with respect to  FIGS. 2 and 3 , it will be apparent to those skilled in the art that any number, kind, and/or configuration of valves and pumps may be used. 
     FIGS.  4  and  5 A- 5 C show an embodiment of a system for removing ingested material from the stomach. In this embodiment, the system includes the fluid source  22 , the drain line  18 , and the patient line  20  and also includes an actuation handle  26  for opening and closing a path between the patient line  20  and the drain line  18  and for opening and closing a path between the fluid source  22  and the patient line  20 . In operation, the actuation handle  26  may toggle the assembly  16  between two modes, a drain mode and an infusion mode. For example, in the drain mode, the actuation handle  26  may be in its original or un-actuated position which may cause the path between the patient line  20  and the drain line  18  to be opened and the path between the fluid source  22  and the patient line  20  to be closed, thus permitting content of the stomach to be drained. When the actuation handle  26  is squeezed or actuated, the actuation handle  26  causes the path between the patient line  20  and the drain line  18  to be closed and the path between the fluid source  22  and the patient line  20  to be opened. The actuation handle  26  causes the fluid source  22  to be squeezed or pumped, forcing the fluid out of the fluid source  22 , thus allowing fluid to flow into the stomach in the infusion mode. For example, a user may squeeze the actuation handle  26  and fluid source  22  by hand. When the actuation handle  26  is released, the actuation handle  26  is returned to its original position, e.g., by a spring force, such as an extension spring, causing the path between the patient line  20  and the drain line  18  to be re-opened and the path between the fluid source  22  and the patient line  20  to be re-closed. The actuation handle  26  may cause the various paths to be opened or closed using any of a variety of approaches that will be apparent to persons skilled in the relevant arts, e.g. by pressing or pinching the various fluid lines or actuating valves. 
     Still referring to FIGS.  4  and  5 A- 5 C, the system may also include a patient line cap  28  and a patient port plug  30  for when the system is not in use and removed from the patient. For example, the assembly  16  may be removed from the patient line  20  and the patient line cap  28  may be used to terminate the patient line  20 . Similarly, the patient port plug  30  may be used to plug the opening where the patient line  20  couples to the assembly  16 . 
     The assembly  16  may also include a rinse slide  32  for opening and closing a path between the fluid source  22  and the drain line  18 . After the system is used to infuse fluid into the stomach and drain contents out of the stomach, the fluid source  22  may be used to rinse out or clean the patient line  20 , the drain line  18  or both. Upon completion of use, the actuation handle  26  may be squeezed with the fluid source  22  to cause fluid to flow through and clean the patient line  20 . Once the patient line  20  is clear, the patient line  20  may be clamped while still holding the actuation handle  26  and the patient line  20  may be disconnected from the assembly  16 . The actuation handle  26  may then be released. In order to clean the drain line  18 , the rinse slide  32  may be activated, allowing fluid to flow from the fluid source  22  down the drain line. When the rinse slide is activated, both valves open and since the drain line is lower than the fluid source, the fluid flows out of the drain line  18 . The actuation handle  26  may then be squeezed with the fluid source  22 , causing fluid to be pumped out of the fluid source  22  and through the drain line  18 , cleaning the drain line  18 . 
     Referring now to  FIG. 4 , optionally, the system may include an attachment mechanism  34  such as a belt clip, for attaching the assembly  16  to the patient during use of the system. Now referring to FIGS.  4  and  5 A- 5 C, the attachment mechanism  34  may be coupled to the assembly  16  at an attachment location  36 . The fluid source  22  may be coupled to the assembly  16  at an attachment assembly  38 . 
       FIGS. 6A and 6B  depict an alternative assembly  16 ′ that may be used in place of the assembly  16  depicted in FIGS.  4  and  5 A- 5 C. In this embodiment an actuation lever  44  alternately either (a) opens a path between the patient line  20  and the drain line  18  or (b) closes the path between the patient line and the drain line. Referring now to  FIG. 6B , when the lever  44  is actuated in this embodiment, it causes the path between the patient line  20  and the drain line  18  to be clamped by clamp  49  and the path between the fluid source  22  and the patient line  20  to be opened. When the fluid source  22  is squeezed while the lever  44  is in an actuated position, fluid from the fluid source  22  will flow through a check valve, into the patient line and into the stomach. When the lever  44  is in a non-actuated position, the path between the patient line  20  and drain line  18  is open. Upon squeezing the fluid source  22  in a non-actuated position, water flows from the fluid source  22  through the drain line  18  and causes a rinsing effect, which obviates the need for the separate rinse slide. In the illustrated embodiment, the actuation lever  44  may cause the paths to be closed/opened by clamp  49  pressing or pinching on the tubing lines. However, persons skilled in the relevant arts will recognize that alternative approaches for opening and closing the various fluid flow paths may be substituted by making appropriate modifications. 
     Since water bottles may have varied thread designs which would not ordinarily mate with conventional female fittings, a universal fluid source receptacle  46  may optionally be implemented to accept any water bottle neck, and to lock around the bottle neck flange. Upon actuation the receptacle releases the flange on the fluid source. This feature may also be implemented in the other embodiments described herein. 
     The system is preferably connected to a gastrostomy tube that has previously been installed in a patient (e.g., through the patient&#39;s abdominal wall), with a port that extends out of the patient&#39;s body. Preferably, the port is relatively flush with the surface of the patient&#39;s abdomen and has a connector that mates with a mating connector of the system. A variety of ways to implement such a flush mount connection interface can be readily envisioned. 
       FIGS. 8-15  depict one preferred implementation of a flush mount connection interface. One part of the interface is the “skin connector”  60  (shown in  FIGS. 9-12 ) which is an implementation of the connection  14  discussed above in connection with  FIG. 1 , and is affixed to the patient and the gastrostomy tube  45  that resides inside the patient&#39;s stomach. This embodiment of the skin connecter  60  includes a rotational valve assembly that controls opening and closing of the pathway into the stomach, as shown in  FIGS. 14A-14B . The other part of the interface is the “tube connector”  65 , also shown in  FIGS. 14A-14B , which is positioned at the upper end of the patient line  20  and is designed to mate with the skin-connector  60  with a fluid-tight interface. 
       FIGS. 9-11  depict a rotational valve assembly  50  that is assembled inside a skin flange  55  to create a flush mount skin connector  60 , and  FIG. 12  is an exploded view of the rotational valve assembly  50 . Three of the valve assembly components  81 ,  82 ,  83  have a thru-hole biased to one quadrant, arranged so that the valve is opened when the thru-holes are aligned and so that the valve is closed when the thru-holes are not aligned. In the preferred embodiment, the size for the entire valve assembly is about 4 cm in diameter, and the size for the thru-holes is about 6-8 mm in diameter. However, in other embodiments, the valve assembly can be proportionally different size, either larger or smaller. The valve assembly  50  is preferably constructed of top platform  81  and a bottom platform  83 , with a layer of elastomer  82  that is attached to the top platform  81  and sandwiched between the top platform and the bottom platform  83  with a force that is high enough to prevent leaks, yet low enough to permit rotation of the elastomer  82  with respect to the bottom platform  83 . The elastomer is attached to the top platform using any adhesive that would attach the silicon to the plastic, however, in one embodiment, a primer and a fast curing adhesive is used. The top platform  81  is preferably made of a lubricious plastic for example, acetyl, and in some embodiments, DELRIN®, TEFLON®, polyethylene, etc, can be used, and the bottom platform  83  is preferably made of ABS or another hard plastic. However, in alternative embodiments, those components may be made of other materials that provide similar functionality. A top retaining ring  80  is configured to attach to the bottom platform  83  to retain the top platform  81  and the middle layer  82  while allowing those two layers to rotate with respect to the bottom platform  83 . Attaching can be in the form of snap fitting, welding, gluing or any other method of attachment. The top retaining ring  80  is preferably also made of ABS or another hard plastic. In the illustrated embodiment, as best seen in  FIGS. 9-11 , the valve assembly  50  has protrusions  53  at its bottom that allows it to fasten to recesses  56  in the skin flange  55  to form the skin connector  60 . The top face of the valve assembly preferably has a structure (e.g., the cut-outs  52 ) for mating with a corresponding surface on the tube connector  65 . The valve assembly  50  can be disassembled from the skin connector  60  by pushing the protrusions  53  at its bottom out of the recesses  56  in the skin flange  55 . With significant force, manually or with a tool directed at the bottom of the recesses  56 , the barbed protrusions  53  can be freed from the recesses  56  in skin flange  55  and the valve assembly  50  can be removed. 
     Removal of the valve may be required when a course of treatment is finished or in connection with valve replacement due to wear, scheduled maintenance, cleanliness, or length adjustment. Using a removable valve permits adjustment of the length of the gastrostomy tube (e.g. after patient weight loss) to compensate for a shortened stoma tract. After the valve is removed, the tube is cut to a shorter length, and then the valve is replaced, advantageously avoiding the need to replace the gastrostomy tube. 
     Due to protrusions  66  on the contacting surface of the tube connector  65  being configured to mate and mechanically couple with the cut-outs  52  on the valve assembly  50  at a rotational distance of approximately 120° from the “open” position of valve assembly  50 , fluid will not leak out of valve assembly  50  during tube connector  65  removal (i.e. disc  68  is always covering the passageway of skin connector  60  prior to removal.) 
     For a gastrostomy tube designed to aspirate food from a full stomach (i.e. larger diameter to accommodate food particles), the fluid pressure may be higher than traditional feeding tubes, and the illustrated valve embodiments can withstand such higher pressures without leaking. The illustrated valve embodiments are also designed to provide a large, uniform lumen from the tube through the valve. The rotational gasket configuration allows sealing of the tube without restricting the lumen dimension when the valve is in the “open” position, thereby minimizing the probability of tube clogging during food aspiration. 
       FIGS. 13A and 13B  depict a tube connector  65  that is connected at the upper end of the patient line  20 . The tube connector  65  is designed to mate with the skin connector, and protrusions  66  on the contacting surface of the tube connector  65  are configured to mate with the cut-outs  52  on the valve assembly  50  (both shown in  FIG. 9B ). The body of the tube connector  65  is preferably constructed of a hard plastic such as ABS. The contacting surface of the tube connector  65  is preferably implemented using a disc  68  made of an elastomeric material such as silicone, with a biased thru-hole  67  that is dimensioned and positioned to match the thru-hole of the skin connector. In the illustrated embodiment, the tube connector  65  has a ridge  71  around the perimeter of its contacting surface that is configured to fit into a mating surface of the skin connector (i.e., the valley  61  around the perimeter of the skin connector  60 , shown in  FIG. 10C ). The outer surface of the illustrated tube connector also has a handle  69  for grasping by the user and a barbed hollow protrusion  70  that is in fluid communication with the thru-hole on the contacting surface for fastening to the patient line tubing. 
     Referring now to FIGS.  10 C and  12 - 14 , when the tube connector  65  and the skin connector  60  are not mated, the valve assembly  50  on the skin connector  60  is in a “closed” position, with the thru-hole  51  in the top platform  81  and the middle layer  82  oriented out of phase with respect to the thru-hole  54  in the bottom platform  83 . To connect the tube connector  65  and the skin connector  60 , the thru-hole  67  of the tube connector is aligned with the thru-hole  51  in the top platform  81  of the valve assembly  50 . The tube connector  65  is then turned by grasping the handle  69  and turning it clockwise. When this happens, the biased thru-hole  51  in the top platform  81  and the middle layer  82  and the thru-hole  67  in the tube connector  65  will all rotate together into alignment with the thru-hole  54  in the bottom platform  83  of the valve assembly  50 , thereby opening a passage to the gastrostomy tube. Rotating the tube connector  65  clockwise also engages mating features  66  on the tube connector with corresponding cut-outs  52  on the valve assembly  50  (shown in  FIG. 9B ) to lock the tube connector  65  to the skin connector. 
     After the passage is open, removal of ingested material from the patient&#39;s stomach is performed, as described above (optionally in alternation with the infusing of liquids into the patient&#39;s stomach). Subsequently, the patient or practitioner rotates the tube connector  65  counterclockwise, which causes the thru-hole  67 , the biased thru-hole  51  in the top platform  81 , and the middle layer  82  to all rotate together away from the thru-hole  54  in the bottom platform  83  of the valve assembly  50 , to the position shown in  FIG. 14A , thereby closing the valve in the skin connector  60 . The tube connector  65  can then be pulled away from the skin connector  60 . 
     Referring now to  FIGS. 10-11 , the skin connector  60  is preferably constructed with an outer skirt  58  composed of a soft, compliant material (e.g. elastomer, foam, etc.) that tapers the fully assembled low-profile skin-port towards the skin to provide a more aesthetic appearance, to prevent the skin connector  60  from catching on the user&#39;s clothing, and to serve as a bumper against applied stresses. In alternative embodiments, the skin connector  60  and tube connector  65  can be configured in various other forms and/or can use different materials to optimize various characteristics. For example, both the skin connector  60  and tube connector  65  can be made with an oblong shape. The mating features and turning of the valve can be actuated by alternate means that will be apparent to persons skilled in the relevant arts, including but not limited to thumbwheel mechanisms, scissor mechanisms, etc. 
     One potential side-effect of aspirating food from the stomach is lowering of electrolytes, such as potassium. The removal of hydrochloric acid (HCl) from the stomach along with food particles can cause the human body to excrete potassium to maintain a charge balance, and excretion of too much potassium can cause hypokalemia. One method for preventing hypokalemia is to give the patient potassium supplements and a proton pump inhibitor. 
     Another method for preventing hypokalemia is to selectively remove HCl from the extracted material, and return it to the patient&#39;s stomach, in order to prevent electrolyte imbalance and obviate the need for additional therapeutics. To achieve acid return to the stomach, the device may be configured with one or more semi-permeable filters that selectively screen out waste product and retain HCl for return to the stomach. Examples of suitable filters include mechanical filters, chemical filters, ionic membranes (e.g. anionic exchange membrane, cationic exchange membrane, bipolar membrane), and electrochemical filtrations systems (or a combination of the above). 
     One way to implement food evacuation with the return of acid to the stomach is by using two filters in series. The first filter, or pre-filter, separates food particles from the fluid. Examples of suitable filters for performing this function include mechanical filters like standard glass-fiber or cellulose filters that selectively remove solids above a specified particle size, leaving “waste” fluid. A suitable porosity for such a filter is 2.5 μm porosity. The second filter removes hydrochloric acid from the pre-filtered fluid. Examples of suitable filters for performing this function include semi-permeable membranes, or an anionic exchange membrane (e.g. NEOSEPTA™, Tokuyama, Japan). 
       FIG. 7A  depicts a first embodiment for returning acid to the stomach. A siphon effect or a pump is used to force evacuated stomach contents through the pre-filter  110  and into one compartment  122  of a dual chamber container  120 , which is separated from the other compartment  126  by an anionic exchange membrane  124 . The second chamber  126  contains deionized water. The difference in ionic concentration between the dual chambers of the cell  120  will drive a diffusion dialysis process to occur in which the Cl −  and H +  ions from hydrochloric acid selectively transfer across the membrane  124  into the water filled chamber  126 . The waste fluid can then be released to exit to the toilet, and a pump  130  can then be actuated to force the HCl and water solution back into the patient&#39;s stomach.  FIG. 7B  depicts an alternative embodiment that is similar to the  FIG. 7A  embodiment, but adds a separate water infusion subsystem  140  to allow the subject to continue to flush and siphon the stomach while the diffusion dialysis process is occurring. More complex filtration system can also be used, including but not limited to electrodialysis, or an anode and a cathode to separate charged ions in an electrophoresis like fluid suspension. The electrofiltration process could potentially decrease the time to remove the HCl from the waste product. 
     Repeated removal of food from a patient&#39;s stomach to achieve weight loss requires close medical supervision to avoid complications (e.g., a drop in electrolyte levels). It may therefore be desirable for the physician to ensure that the patient returns for follow-up and blood testing to avoid improper use of the device, or at a minimum have data that reveals the patient compliance with proper use of the system. A shut-off mechanism may be built into the system to ensure that the patient returns for such follow-up. The shut-off mechanism preferably operates based on some measurement of usage such as the passage of time (e.g., to disable the device after one month), the number of cycles of use (e.g., to disable the device after 90 uses), or the volume of extracted matter (e.g., to disable the device after 50 liters of material have been removed). 
     The measurement of usage may be implemented by mechanical or electrical means, as will be appreciated by persons skilled in the relevant arts (e.g., using a mechanical counter such as a multi-decade geared mechanism that is incremented using a cam-actuated sprocket, or an electrical counter that is incremented by a suitable sensor). Suitable events that can be used to increment the count include, but are not limited to, the connection of a water bottle to the system, the connection of the tube connector to the skin connector, etc. The shut-off mechanism may also be implemented by mechanical or electrical means. One example of a suitable mechanical shut-off mechanism is a preloaded spring mechanism that, when actuated, blocks fluid from moving through one of the system&#39;s tubes. An example of a suitable electrical device for implementing shut-off is a solenoid actuated valve, and a wide variety of alternatives will be apparent to persons skilled in the relevant arts. The shut-off mechanism may be designed to permanently disable the device, in which case the patient would have to obtain a new device to continue using the system. Alternatively, it may be configured to be resettable by a doctor (e.g., using an electronic shut-off mechanism that can be reset by entry of a password or a biometric key such as a fingerprint detector). After the patient is examined by the doctor (e.g., using blood tests to confirm healthy electrolyte levels), the doctor could provide a new device or reset the shut-off mechanism. 
     One application of some of the above-described embodiments is to implement a method of removing ingested food from a patient&#39;s stomach via a gastrostomy tube that passes through the patient&#39;s abdominal wall into the patient&#39;s stomach. This method includes the steps of: (a) siphoning a first portion of the ingested food out of the patient&#39;s stomach via the gastrostomy tube; (b) infusing liquid into the patient&#39;s stomach via the gastrostomy tube; and (c) siphoning at least some of the infused liquid out of the patient&#39;s stomach via the gastrostomy tube, together with a second portion of the ingested food. Optionally, this method may further include the steps of: (d) infusing liquid into the patient&#39;s stomach via the gastrostomy tube; and (e) siphoning at least some of the infused liquid out of the patient&#39;s stomach via the gastrostomy tube, together with a third portion of the ingested food, wherein step (d) is performed after step (c), and wherein step (e) is performed after step (d). 
     Another application of some of the above-described embodiments is to implement an apparatus for removing food from a patient&#39;s stomach via a gastrostomy tube that passes through the patient&#39;s abdominal wall into the patient&#39;s stomach. This apparatus includes: a connector configured to connect to a proximal end of the gastrostomy tube with a fluid-tight connection; a first fluid path provided between the connector and a drain port, configured to permit siphoning or pumping food from the patient&#39;s stomach out to the drain port; a second fluid path provided between the connector and an input port, configured to permit infusion of liquid from the input port into the patient&#39;s stomach; and a fluid circuit configured to alternately (a) open the first fluid path during a first interval of time to permit siphoning or pumping food out of the patient&#39;s stomach and (b) open the second fluid path during a second interval of time to permit infusion of the liquid in the reservoir into the patient&#39;s stomach. 
     Another application of some of the above-described embodiments is to implement a method of removing ingested material from a stomach of a patient fitted with an external gastrostomy connection to the stomach. This method includes: coupling a siphon tube to the connection so as to create a siphon system having an aggregate length in excess of 25 cm; and draining content of the stomach through the siphon tube. 
     Another application of some of the above-described embodiments is to implement a method of removing ingested material from a stomach of a patient fitted with an external gastrostomy connection to the stomach. This method includes the steps of: pumping a fluid through the connection into the stomach to increase fluid in the stomach without ingestion of fluid; and draining content of the stomach through the connection. Optionally, the fluid may include one or more of the following: water, a nutrient, a medication, and returned gastric juices. 
     Another application of some of the above-described embodiments is to implement an apparatus for removing ingested material from a stomach of a patient fitted with an external gastrostomy connection to the stomach. This apparatus includes: a fluid source for infusing fluid into the stomach through the connection; and a drain line for draining content of the stomach received from the connection. Optionally, a siphon system is used for passively draining content of the stomach, preferably using flat tubing. Optionally, a pump may be coupled to the fluid source for pumping fluid through the connection into the stomach. 
     Another application of some of the above-described embodiments is to implement a method of removing ingested food from a patient&#39;s stomach via a gastrostomy tube that passes through the patient&#39;s abdominal wall into the patient&#39;s stomach. This method includes the steps of: (a) extracting a portion of the matter contained in the patient&#39;s stomach via the gastrostomy tube; (b) removing stomach acid from the matter extracted in the extracting step; and (c) returning the stomach acid removed in the removing step to the patient&#39;s stomach via the gastrostomy tube. Optionally, the removing step includes the steps of: (i) filtering out solid portions from the matter extracted in the extracting step; and (ii) filtering a liquid resulting from step (i) using a semi-permeable membrane or an anionic exchange membrane. In this application, the extracting step may be implemented by siphoning or pumping. 
     Another application of some of the above-described embodiments is to implement an apparatus for removing food from a patient&#39;s stomach via a gastrostomy tube that passes through the patient&#39;s abdominal wall into the patient&#39;s stomach. This apparatus includes: a connector configured to connect to a proximal end of the gastrostomy tube with a fluid-tight connection; a filter configured to separate stomach acid from other matter; a first path from the connector to the filter, configured to route matter extracted from the patient&#39;s stomach into the filter; a pump configured to pump stomach acid that has been separated by the filter back into the patient&#39;s stomach; and a second path configured to route the other matter to a waste outlet. In this application, the matter extracted from the patient&#39;s stomach may be routed into the filter by pumping or siphoning. Optionally, this apparatus may further include a reservoir configured to hold liquid and a pump configured to pump the liquid from the reservoir into the patient&#39;s stomach via the connector. 
     Another application of some of the above-described embodiments is to implement a method of removing ingested food from a patient&#39;s stomach via a gastrostomy tube that passes through the patient&#39;s abdominal wall into the patient&#39;s stomach. This method includes the steps of: providing an apparatus for siphoning or pumping ingested food out of the patient&#39;s stomach via the gastrostomy tube; and limiting the number of times that the siphoning or pumping operation can be performed by the apparatus. The number of times that the siphoning or pumping operation can be performed may be limited by a variety of factors such as (a) elapsed time from a first use, (b) how many times siphoning or pumping of food has been performed, (c) how many times the apparatus has been connected to the gastrostomy tube, or (d) the volume of matter that has been extracted from the patient&#39;s stomach. Optionally, this method may further include the step of infusing liquid into the patient&#39;s stomach via the gastrostomy tube, wherein the infusing step is performed in alternation with the siphoning or pumping. 
     Another application of some of the above-described embodiments is to implement an apparatus for removing food from a patient&#39;s stomach via a gastrostomy tube that passes through the patient&#39;s abdominal wall into the patient&#39;s stomach. This apparatus includes: a connector configured to connect to a proximal end of the gastrostomy tube with a fluid-tight connection; and a first fluid path provided between the connector and a drain port, configured to permit, for a limited number of times only, siphoning or pumping food from the patient&#39;s stomach out to the drain port. The number of times that the siphoning or pumping can be performed may be limited by a variety of factors such as (a) elapsed time from a first use, (b) how many times siphoning or pumping of food has been performed, (c) how many times the apparatus has been connected to the gastrostomy tube, or (d) the volume of matter that has been extracted from the patient&#39;s stomach. Optionally, this apparatus may further include: a reservoir for holding liquid to be infused into the patient&#39;s stomach; a second fluid path from the reservoir to the connector, configured to permit infusion of the liquid in the reservoir into the patient&#39;s stomach; and a fluid circuit configured to alternately (a) open the first fluid path during a first interval of time to permit siphoning or pumping food from the patient&#39;s stomach and (b) open the second fluid path during a second interval of time to permit infusion of the liquid in the reservoir into the patient&#39;s stomach. 
     Note that while the system is described herein in the context of removing the ingested material from the patient&#39;s stomach, it can also be used to remove the ingested material from other portions of the patient&#39;s upper digestive tract (e.g., the jejunum). 
     Although the above discussion discloses various exemplary embodiments of the invention, it should be apparent that those skilled in the art can make variations and modifications that will achieve some of the advantages of the invention without departing from the true scope of the invention. Accordingly, other embodiments are within the scope of the following claims.