Patent Description:
Hypervolemia, or fluid overload, is a medical condition in which the volume of blood in the intravascular compartment is in excess of normal as a result of plasma retaining too much water. Water can accumulate in patients suffering from chronic kidney disease, particularly in advanced stages thereof such as end-stage renal disease ("ESRD"), where the kidneys are no longer effective in filtering out water in excess of that the body needs. Water can also accumulate in patients suffering from chronic heart disease such as congestive heart failure ("CHF"), where the heart is no longer effective in pumping the blood to the kidneys to filter out the water in excess of that the body needs. The volume of blood in the intravascular compartment in excess of normal can lead to fluid buildup in the peritoneal and pleural cavities causing shortness of breath, which can degrade quality of life. The volume of blood in the intravascular compartment in excess of normal can also lead to hypertension and stress on the heart, which can exacerbate other diseases such as CHF leading to death. Therefore, managing hypervolemia is important to those suffering from the medical condition. Disclosed herein is an implantable device and methods thereof that address the foregoing. <CIT> relates to a medical device comprising a partially porous mesh that forms a fibrosis cage for accessing fluid from the patient upon implantation into a patient, and a pump for pumping fluid into and out of the fibrosis cage.

Disclosed herein is an implantable device for treating hypervolemia including an expandable chamber, a rigid chamber coupled to the expandable chamber, a first valve in fluid communication with both the expandable chamber and the rigid chamber, a second valve in fluid communication with the rigid chamber and an exterior of the implantable device, and an osmotic fluid. The expandable chamber includes a first semipermeable membrane. The rigid chamber includes a piston. The first valve has an open position to permit fluid flow between the expandable chamber and the rigid chamber. The second valve has an open position to permit fluid flow from the rigid chamber to the exterior of the implantable device. The osmotic fluid has a higher osmotic concentration than bodily fluid. The osmotic fluid is designed to absorb water from the bodily fluid through the first semipermeable membrane.

In some embodiments, the implantable device further includes a pump. The pump is designed to move any fluid contents of the implantable device through the first valve in the open position or the second valve in the open position.

In some embodiments, the piston is configured to perform a pump-actuated pull stroke in the rigid chamber when the first valve is in the open position to pull any fluid contents of the expandable chamber into the rigid chamber.

In some embodiments, the piston is configured to perform a pump-actuated push stroke in the rigid chamber when the second valve is in the open position to push any fluid contents in the rigid chamber and expel permeate from the implantable device.

In some embodiments, at least one of the first semipermeable membrane or the second semipermeable membrane is a dialysis membrane.

In some embodiments, the osmotic fluid is an aqueous solution of a dissolved polymer.

In some embodiments, the first semipermeable membrane and the second semipermeable membrane are designed to prevent the aqueous solution of the dissolved polymer from passing through.

In some embodiments, the implantable device is configured for implantation in a peritoneal cavity of a patient.

In some embodiments, the implantable device is shunted to a ureter of the patient for elimination of excess water through the bladder.

In some embodiments, the implantable device further includes an inductive coil configured to couple with a complementary inductive coil of a companion device, wherein the companion device is operable to couple with mains electricity to charge or power the implantable device by induction.

Also disclosed herein is an implantable device for treating hypervolemia including an expandable chamber, a rigid chamber including a piston, a first valve between the expandable chamber and the rigid chamber, a second valve between the rigid chamber and an exterior of the rigid chamber, and a fluid within the implantable device. The expandable chamber includes a first semipermeable membrane over at least a portion of the expandable chamber. The expandable chamber is configured to expand when the fluid is disposed in the expandable chamber and osmotically absorb water through the first semipermeable membrane from a bodily fluid outside the expandable chamber having a lower osmotic concentration. The first valve between the expandable chamber and the rigid chamber is configured to allow the fluid to flow between the expandable chamber and the rigid chamber when the first valve is open. The second valve between the rigid chamber and the exterior of the rigid chamber is configured to allow the fluid to flow from the rigid chamber into a second semipermeable membrane to expel the water from the implantable device when the second valve is open.

In some embodiments, the implantable device further includes a pump. The pump is configured to operate in concert with both the first valve and the second valve. The pump is configured to move the fluid between the expandable chamber and the rigid chamber when the first valve is open, and the pump is configured to move the fluid from the rigid chamber to the second semipermeable membrane when the second valve is open.

In some embodiments, the piston is configured to perform a pump-actuated pull stroke in the rigid chamber when the first valve is open to pull the fluid from the expandable chamber into the rigid chamber.

In some embodiments, the piston is configured to perform a pump-actuated push stroke in the rigid chamber when the second valve is open to push the fluid from the rigid chamber through the second semipermeable membrane to expel the water from the implantable device.

In some embodiments, the first semipermeable membrane, the second semipermeable membrane, or both the semipermeable membranes are dialysis membranes.

In some embodiments, the fluid within the implantable device is an aqueous solution of a dissolved polymer.

In some embodiments, the fluid within the implantable device is an aqueous solution of a dissolved polymer excluded from passing through the first and second semipermeable membranes.

In some embodiments, the implantable device is configured for implantation in a peritoneal cavity of a patient to remove water in excess of that the patient needs.

In some embodiments, the implantable device is shunted to a ureter of the patient for elimination of the water in excess of that the patient needs through the bladder.

In some embodiments, the implantable device further includes an inductive coil configured to couple with a complementary inductive coil of a companion device operable to couple with mains electricity to charge or power the implantable device by induction.

Also disclosed herein is an implantable device for treating hypervolemia including a first expandable chamber, a second expandable chamber, a rigid chamber including a piston, a number of valves, and a fluid within the implantable device. The first expandable chamber includes a first semipermeable membrane over at least a portion of the first expandable chamber. The second expandable chamber includes a second semipermeable membrane over at least a portion of the second expandable chamber. Each expandable chamber of the first and second expandable chambers is configured to expand when the fluid is disposed therein and osmotically absorb water from a bodily fluid outside the implantable device having a lower osmotic concentration. The number of valves includes a first valve between the first expandable chamber and the rigid chamber and a second valve between the second expandable chamber and the rigid chamber. Each valve of the first and second valves is configured to allow the fluid to flow between adjacent chambers when the valve is open. The number of valves also includes a third valve between the rigid chamber and an exterior of the rigid chamber and a fourth valve between the rigid chamber and the exterior of the rigid chamber, wherein the third valve and the fourth valve are separated from each other by the piston. The third valve is configured to allow the fluid to flow from the rigid chamber into a third semipermeable membrane to expel the water from the implantable device when the third valve is open. The fourth valve is configured to allow the fluid to flow from the rigid chamber into a fourth semipermeable membrane to expel the water from the implantable device when the fourth valve is open.

In some embodiments, the implantable device further includes a pump. The pump is configured to operate in concert with the number of valves. The pump is configured to move the fluid between the first expandable chamber and the rigid chamber when the first valve is open while also moving the fluid from the rigid chamber to the fourth semipermeable membrane when the fourth valve is open. The pump is also configured to move the fluid between the second expandable chamber and the rigid chamber when the second valve is open while also moving the fluid from the rigid chamber to the third semipermeable membrane when the third valve is open.

In some embodiments, the piston is configured to perform a pump-actuated pull stroke in the rigid chamber when the first and fourth valves are open to simultaneously pull the fluid from the first expandable chamber into the rigid chamber and push the fluid from the rigid chamber through the fourth semipermeable membrane to expel the water from the implantable device.

In some embodiments, the piston is configured to perform a pump-actuated push stroke in the rigid chamber when the second and third valves are open to simultaneously push the fluid from the rigid chamber through the third semipermeable membrane to expel the water from the implantable device and pull the fluid from the second expandable chamber into the rigid chamber.

In some embodiments, each semipermeable membrane of the first, second, third, and fourth semipermeable membranes is a dialysis membranes.

In some embodiments, the fluid within the implantable device is an aqueous solution of a dissolved polymer excluded from passing through the first, second, third, and fourth semipermeable membranes.

These and other features of the concepts provided herein will become more apparent to those of skill in the art in view of the accompanying drawings and following description, which disclose particular embodiments of such concepts in greater detail. The invention is defined by he appended claims.

Before some particular embodiments are disclosed in greater detail, it should be understood that the scope of the invention is only limited by the claims.

Labels such as "left," "right," "front," "back," "top," "bottom," and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction.

As set forth above, hypervolemia, or fluid overload, is a medical condition in which the volume of blood in the intravascular compartment is in excess of normal as a result of plasma retaining too much water. Water can accumulate in patients suffering from chronic kidney disease, particularly in advanced stages thereof such as end-stage renal disease ("ESRD"), where the kidneys are no longer effective in filtering out water in excess of that the body needs. Water can also accumulate in patients suffering from chronic heart disease such as congestive heart failure ("CHF"), where the heart is no longer effective in pumping the blood to the kidneys to filter out the water in excess of that the body needs. The volume of blood in the intravascular compartment in excess of normal can lead to fluid buildup in the peritoneal and pleural cavities causing shortness of breath, which can degrade quality of life. The volume of blood in the intravascular compartment in excess of normal can also lead to hypertension and stress on the heart, which can exacerbate other diseases such as CHF leading to death. Therefore, managing hypervolemia is important to those suffering from the medical condition. Disclosed herein is an implantable device and methods thereof that address the foregoing.

<FIG> illustrate a device <NUM> for treating hypervolemia in a number of different stages of operation in accordance with some embodiments.

As shown, the implantable device <NUM> includes an expandable chamber <NUM>, a rigid chamber <NUM> including a piston <NUM>, a first valve <NUM> between the expandable chamber <NUM> and the rigid chamber <NUM>, a second valve <NUM> between the rigid chamber <NUM> and an exterior of the rigid chamber <NUM>, and a fluid <NUM> within the implantable device <NUM>.

The expandable chamber <NUM> includes a first semipermeable membrane <NUM> over at least a portion of the expandable chamber <NUM>. The expandable chamber <NUM> is configured to expand when the fluid <NUM> is disposed in the expandable chamber <NUM> and osmotically absorb water into the fluid <NUM> through the first semipermeable membrane <NUM> from a bodily fluid outside the expandable chamber <NUM> having a lower osmotic concentration than the fluid <NUM>. (See <FIG> and <FIG>.

The first valve <NUM> between the expandable chamber <NUM> and the rigid chamber <NUM> is configured with an open position to allow or permit the fluid <NUM> to flow between the expandable chamber <NUM> and the rigid chamber <NUM> when the first valve <NUM> is open or in the open position. (See <FIG> and <FIG>.

The second valve <NUM> between the rigid chamber <NUM> and the exterior of the rigid chamber <NUM> is configured with an open position to allow or permit the fluid <NUM> to flow from the rigid chamber <NUM> into a second semipermeable membrane <NUM> to expel the water from the implantable device <NUM> when the second valve <NUM> is open or in the open position. (See <FIG> and <FIG>.

The implantable device <NUM> further includes a pump (not shown) such as a gear-driven piston pump to move any fluid contents of the implantable device through the implantable device <NUM> (e.g., through the first valve <NUM> or the second valve <NUM> when in the opened position). The pump is configured to operate in concert with both the first valve <NUM> and the second valve <NUM>. The pump is configured to move the fluid <NUM> between the expandable chamber <NUM> and the rigid chamber <NUM> when the first valve <NUM> is open. The pump is also configured to move the fluid <NUM> from the rigid chamber <NUM> to the second semipermeable membrane <NUM> when the second valve <NUM> is open.

The piston <NUM> is configured to perform a pump-actuated pull stroke in the rigid chamber <NUM> when the first valve <NUM> is open to pull any fluid contents such as the fluid <NUM> from the expandable chamber <NUM> into the rigid chamber <NUM>. The piston <NUM> is also configured to perform a pump-actuated push stroke in the rigid chamber <NUM> when the second valve <NUM> is open to push any fluid contents such as the fluid <NUM> from the rigid chamber <NUM> through the second semipermeable membrane <NUM> to expel the water (as permeate) from the implantable device <NUM>, thereby producing a retentate of the fluid <NUM>. Upon closing the second valve <NUM>, or returning the second valve to a closed position, and opening the first valve <NUM>, or returning the first valve <NUM> to the open position, the pump-actuated push stroke can be further utilized to push the retentate of the fluid <NUM> from the rigid chamber <NUM> into the expandable chamber <NUM> for another cycle.

In addition to the foregoing, the pump-actuated strokes can be utilized in a cycling mode of operation of the implantable device <NUM>, in which the fluid <NUM> is cycled back and forth between the expandable chamber <NUM> and the rigid chamber <NUM> through the first valve <NUM> when in the open position. The cycling mode of operation ensures the fluid <NUM> is mixed such that the osmotic concentration of the fluid <NUM> near an inside surface of semipermeable membrane <NUM> remains high enough for osmosis through the semipermeable membrane <NUM>. Depending upon the activity level of the patient in which the implantable device <NUM> is implanted the cycling mode of operation of the implantable device <NUM> might not be necessary. That is, the activity level of the patient might be enough to mix the fluid <NUM> to maintain a high enough osmotic concentration of the fluid <NUM> near the inside surface of semipermeable membrane <NUM> for water osmosis through the semipermeable membrane <NUM>.

<FIG> illustrates another device <NUM> for treating hypervolemia in accordance with some embodiments.

As shown, the implantable device <NUM> includes the first expandable chamber <NUM>, a second expandable chamber <NUM>, the rigid chamber <NUM> including the piston <NUM>, a number of valves <NUM>, <NUM>, <NUM>, <NUM>, and the fluid <NUM> within the implantable device <NUM>.

The first expandable chamber <NUM> includes the first semipermeable membrane <NUM> over at least a portion of the first expandable chamber <NUM> as described in reference to the implantable device <NUM>. Likewise, the additional second expandable chamber <NUM> includes a second semipermeable membrane <NUM> over at least a portion of the second expandable chamber <NUM>. Each expandable chamber of the first and second expandable chambers <NUM>, <NUM> is configured to expand when the fluid <NUM> is disposed therein and osmotically absorbs water from a bodily fluid outside the implantable device <NUM>. That is, the expandable chamber <NUM> expands when the fluid <NUM> in the expandable chamber <NUM> osmotically absorbs water into the fluid <NUM> through the first semipermeable membrane <NUM> from the bodily fluid outside the expandable chamber <NUM> when the bodily fluid has a lower osmotic concentration than the fluid <NUM>, and the expandable chamber <NUM> expands when the fluid <NUM> in the expandable chamber <NUM> osmotically absorbs water into the fluid <NUM> through the second semipermeable membrane <NUM> from the bodily fluid outside the expandable chamber <NUM> when the bodily fluid has a lower osmotic concentration than the fluid <NUM>.

The number of valves includes the first valve <NUM> between the first expandable chamber <NUM> and the rigid chamber <NUM> and a second valve <NUM> between the second expandable chamber <NUM> and the rigid chamber <NUM>. Each valve of the first and second valves <NUM>, <NUM> is configured with an open position to allow or permit the fluid <NUM> to flow between adjacent chambers when the valve is open or in the open position. That is, the first valve <NUM> between the expandable chamber <NUM> and the rigid chamber <NUM> is configured to allow the fluid <NUM> to flow between the expandable chamber <NUM> and the rigid chamber <NUM> when the first valve <NUM> is open, and the second valve <NUM> between the expandable chamber <NUM> and the rigid chamber <NUM> is configured to allow the fluid <NUM> to flow between the expandable chamber <NUM> and the rigid chamber <NUM> when the second valve <NUM> is open. The number of valves also includes a third valve <NUM> between the rigid chamber <NUM> and an exterior of the rigid chamber <NUM> and a fourth valve <NUM> between the rigid chamber <NUM> and the exterior of the rigid chamber <NUM>, wherein the third valve <NUM> and the fourth valve <NUM> are separated from each other by the piston <NUM>. The third valve <NUM> is configured with an open position to allow or permit the fluid <NUM> to flow from the rigid chamber <NUM> into a third semipermeable membrane <NUM> to expel the water from the implantable device <NUM> when the third valve <NUM> is open or in the open position. The fourth valve <NUM> is configured with an open position to allow or permit the fluid <NUM> to flow from the rigid chamber <NUM> into a fourth semipermeable membrane <NUM> to expel the water from the implantable device <NUM> when the fourth valve <NUM> is open or in the open position.

The implantable device <NUM> further includes a pump (not shown) as described in reference to the implantable device <NUM>. Likewise, the pump is configured to operate in concert with the number of valves <NUM>, <NUM>, <NUM>, <NUM>. The pump is configured to move the fluid <NUM> between the first expandable chamber <NUM> and the rigid chamber <NUM> when the first valve <NUM> is open while also moving the fluid <NUM> from the rigid chamber <NUM> to the fourth semipermeable membrane <NUM> when the fourth valve <NUM> is open. The pump is also configured to move the fluid <NUM> between the second expandable chamber <NUM> and the rigid chamber <NUM> when the second valve <NUM> is open while also moving the fluid <NUM> from the rigid chamber <NUM> to the third semipermeable membrane <NUM> when the third valve <NUM> is open.

The piston <NUM> is configured to perform a pump-actuated pull stroke in the rigid chamber <NUM> when the first and fourth valves <NUM>, <NUM> are open to simultaneously pull any fluid contents such as the fluid <NUM> from the first expandable chamber <NUM> into the rigid chamber <NUM> proximate the first expandable chamber <NUM> and push any fluid contents such as the fluid <NUM> from the rigid chamber <NUM> proximate the expandable chamber <NUM> through the fourth semipermeable membrane <NUM> to expel the water from the implantable device <NUM>. The piston <NUM> is also configured to perform a pump-actuated push stroke in the rigid chamber <NUM> when the second and third <NUM>, <NUM> valves are open to simultaneously push any fluid contents such as the fluid <NUM> from the rigid chamber <NUM> proximate the first expandable chamber <NUM> through the third semipermeable membrane <NUM> to expel the water from the implantable device <NUM> and pull any fluid contents such as the fluid <NUM> from the second expandable chamber <NUM> into the rigid chamber <NUM> proximate the second expandable chamber <NUM>. Like the pump-actuated push stroke described in reference to the implantable device <NUM>, the foregoing pump-actuated strokes can be further utilized with timely opening and closing of the valves to push the retentate of the fluid <NUM> from the rigid chamber <NUM> into the expandable chambers <NUM>, <NUM> for additional cycles. In addition, the foregoing pump-actuated strokes can be further utilized in a cycling mode of operation like that of the implantable device <NUM>.

Each semipermeable membrane of the first, second, third, and fourth semipermeable membranes <NUM>, <NUM>, <NUM>, <NUM> of the implantable devices <NUM> and <NUM> can have pores of a pore size that allows water to permeate through the semipermeable membrane but not larger metabolites such as polypeptides or proteins, cell fragments such as platelets, or cells such as red blood cells or white blood cells. However, the pores of the semipermeable membrane can be sized to allow ions such as Na+, K+, Ca<NUM>+, Mg<NUM>+, or Cl- to permeate through the semipermeable membrane, as well as molecules of lower molecular weight than the foregoing larger metabolites such as urea or creatinine. An example of such a semipermeable membrane includes, but is not limited to, a dialysis membrane.

The fluid <NUM>, or osmotic fluid, within the implantable device <NUM> or <NUM> can be an aqueous solution of a dissolved polymer such as poly(ethylene glycol) ("PEG") or sodium polyacrylate, which dissolved polymer is excluded based on size from passing through any semipermeable membrane of the first, second, third, and fourth semipermeable membranes <NUM>, <NUM>, <NUM>, <NUM>. The initial or basal concentration of the dissolved polymer in the fluid <NUM> is sufficient to create an osmotic potential for removing the water in excess of that the patient needs through the first semipermeable membrane <NUM> or the second semipermeable membrane <NUM> while the implanted device <NUM> or <NUM> is implanted in the patient. That is, the osmotic fluid has a higher osmotic concentration than bodily fluid, which allows the osmotic fluid to absorb water from the bodily fluid through the first semipermeable membrane <NUM> or the second semipermeable membrane <NUM> while the implanted device <NUM> or <NUM> is implanted in the patient.

Each implantable device of the implantable device <NUM> and the implantable device <NUM> is configured for implantation in at least a peritoneal cavity of a patient to remove water that builds up in the patient's peritoneal cavity (a condition known as ascites) for one or more reasons including hypervolemia or liver disease. The peritoneal cavity is an advantageous location for the implantable device <NUM>, <NUM> because movement of the patient allows the fluid <NUM> in the expandable chambers <NUM>, <NUM> to keep moving fluid around, thereby encouraging movement that maintains a concentration gradient that promotes osmosis. In addition, the implantable device <NUM> can be shunted to a ureter of the patient for elimination of the water in excess of that the patient needs through the patient's bladder.

Because the implantable devices <NUM> and <NUM> are electrically powered devices, each implantable devices of the implantable device <NUM> and the implantable device <NUM> further includes an inductive coil (not shown) configured to couple with a complementary inductive coil of a companion device such as a belt operable to couple with mains electricity to charge or power the implantable device by induction. For example, the belt can be plugged in and worn during the day when the patient is resting or at night when the patient is sleeping.

Claim 1:
An implantable device (<NUM>,<NUM>) for treating hypervolemia, comprising:
an expandable chamber (<NUM>) including a first semipermeable membrane (<NUM>);
a rigid chamber (<NUM>) coupled to the expandable chamber (<NUM>), the rigid chamber (<NUM>) including a piston (<NUM>);
a first valve (<NUM>) in fluid communication with both the expandable chamber (<NUM>) and the rigid chamber (<NUM>), the first valve (<NUM>) having an open position to permit fluid flow between the expandable chamber (<NUM>) and the rigid chamber (<NUM>);
a second valve (<NUM>) in fluid communication with the rigid chamber (<NUM>) and an exterior of the implantable device (<NUM>,<NUM>), the second valve (<NUM>) including a second semipermeable membrane (<NUM>), the second valve (<NUM>) having an open position to permit fluid flow from the rigid chamber (<NUM>) to the exterior of the implantable device (<NUM>,<NUM>); and
an osmotic fluid (<NUM>) having a higher osmotic concentration than bodily fluid, the osmotic fluid designed to absorb water from the bodily fluid through the first semipermeable membrane (<NUM>).