Patent ID: 12220510

DESCRIPTION

Before some particular embodiments are disclosed in greater detail, it should be understood that the particular embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment disclosed herein can have features that can be readily separated from the particular embodiment and optionally combined with or substituted for features of any of a number of other embodiments disclosed herein.

Regarding terms used herein, it should also be understood the terms are for the purpose of describing some particular embodiments, and the terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. For example, “first,” “second,” and “third” features or steps need not necessarily appear in that order, and the particular embodiments including such features or steps need not necessarily be limited to the three features or steps. 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. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. Singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art.

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.

FIGS.1A-1Fillustrate a device100for treating hypervolemia in a number of different stages of operation in accordance with some embodiments.

As shown, the implantable device100includes an expandable chamber110, a rigid chamber120including a piston122, a first valve132between the expandable chamber110and the rigid chamber120, a second valve134between the rigid chamber120and an exterior of the rigid chamber120, and a fluid140within the implantable device100.

The expandable chamber110includes a first semipermeable membrane112over at least a portion of the expandable chamber110. The expandable chamber110is configured to expand when the fluid140is disposed in the expandable chamber110and osmotically absorb water into the fluid140through the first semipermeable membrane112from a bodily fluid outside the expandable chamber110having a lower osmotic concentration than the fluid140. (SeeFIGS.1A and1B.)

The first valve132between the expandable chamber110and the rigid chamber120is configured with an open position to allow or permit the fluid140to flow between the expandable chamber110and the rigid chamber120when the first valve132is open or in the open position. (SeeFIGS.1B and1C.)

The second valve134between the rigid chamber120and the exterior of the rigid chamber120is configured with an open position to allow or permit the fluid140to flow from the rigid chamber120into a second semipermeable membrane124to expel the water from the implantable device100when the second valve134is open or in the open position. (SeeFIGS.1D and1E.)

The implantable device100further includes a pump (not shown) such as a gear-driven piston pump to move any fluid contents of the implantable device through the implantable device100(e.g., through the first valve132or the second valve134when in the opened position). The pump is configured to operate in concert with both the first valve132and the second valve134. The pump is configured to move the fluid140between the expandable chamber110and the rigid chamber120when the first valve132is open. The pump is also configured to move the fluid140from the rigid chamber120to the second semipermeable membrane124when the second valve134is open.

The piston122is configured to perform a pump-actuated pull stroke in the rigid chamber120when the first valve132is open to pull any fluid contents such as the fluid140from the expandable chamber110into the rigid chamber120. The piston122is also configured to perform a pump-actuated push stroke in the rigid chamber120when the second valve134is open to push any fluid contents such as the fluid140from the rigid chamber120through the second semipermeable membrane124to expel the water (as permeate) from the implantable device100, thereby producing a retentate of the fluid140. Upon closing the second valve134, or returning the second valve to a closed position, and opening the first valve132, or returning the first valve132to the open position, the pump-actuated push stroke can be further utilized to push the retentate of the fluid140from the rigid chamber120into the expandable chamber110for another cycle.

In addition to the foregoing, the pump-actuated strokes can be utilized in a cycling mode of operation of the implantable device100, in which the fluid140is cycled back and forth between the expandable chamber110and the rigid chamber120through the first valve132when in the open position. The cycling mode of operation ensures the fluid140is mixed such that the osmotic concentration of the fluid140near an inside surface of semipermeable membrane124remains high enough for osmosis through the semipermeable membrane124. Depending upon the activity level of the patient in which the implantable device100is implanted the cycling mode of operation of the implantable device100might not be necessary. That is, the activity level of the patient might be enough to mix the fluid140to maintain a high enough osmotic concentration of the fluid140near the inside surface of semipermeable membrane124for water osmosis through the semipermeable membrane124.

FIG.2illustrates another device200for treating hypervolemia in accordance with some embodiments.

As shown, the implantable device200includes the first expandable chamber110, a second expandable chamber210, the rigid chamber120including the piston122, a number of valves132,134,232,234, and the fluid140within the implantable device200.

The first expandable chamber110includes the first semipermeable membrane112over at least a portion of the first expandable chamber110as described in reference to the implantable device100. Likewise, the additional second expandable chamber210includes a second semipermeable membrane212over at least a portion of the second expandable chamber210. Each expandable chamber of the first and second expandable chambers110,210is configured to expand when the fluid140is disposed therein and osmotically absorbs water from a bodily fluid outside the implantable device200. That is, the expandable chamber110expands when the fluid140in the expandable chamber110osmotically absorbs water into the fluid140through the first semipermeable membrane112from the bodily fluid outside the expandable chamber110when the bodily fluid has a lower osmotic concentration than the fluid140, and the expandable chamber210expands when the fluid140in the expandable chamber210osmotically absorbs water into the fluid140through the second semipermeable membrane212from the bodily fluid outside the expandable chamber210when the bodily fluid has a lower osmotic concentration than the fluid140.

The number of valves includes the first valve132between the first expandable chamber110and the rigid chamber120and a second valve232between the second expandable chamber210and the rigid chamber120. Each valve of the first and second valves132,232is configured with an open position to allow or permit the fluid140to flow between adjacent chambers when the valve is open or in the open position. That is, the first valve132between the expandable chamber110and the rigid chamber120is configured to allow the fluid140to flow between the expandable chamber110and the rigid chamber120when the first valve132is open, and the second valve232between the expandable chamber210and the rigid chamber120is configured to allow the fluid140to flow between the expandable chamber210and the rigid chamber220when the second valve232is open. The number of valves also includes a third valve134between the rigid chamber120and an exterior of the rigid chamber120and a fourth valve234between the rigid chamber120and the exterior of the rigid chamber120, wherein the third valve134and the fourth valve234are separated from each other by the piston122. The third valve134is configured with an open position to allow or permit the fluid140to flow from the rigid chamber120into a third semipermeable membrane124to expel the water from the implantable device200when the third valve134is open or in the open position. The fourth valve234is configured with an open position to allow or permit the fluid140to flow from the rigid chamber120into a fourth semipermeable membrane224to expel the water from the implantable device200when the fourth valve234is open or in the open position.

The implantable device200further includes a pump (not shown) as described in reference to the implantable device100. Likewise, the pump is configured to operate in concert with the number of valves132,134,232,234. The pump is configured to move the fluid140between the first expandable chamber110and the rigid chamber120when the first valve123is open while also moving the fluid140from the rigid chamber120to the fourth semipermeable membrane224when the fourth valve234is open. The pump is also configured to move the fluid140between the second expandable chamber210and the rigid chamber120when the second valve232is open while also moving the fluid140from the rigid chamber210to the third semipermeable membrane124when the third valve134is open.

The piston122is configured to perform a pump-actuated pull stroke in the rigid chamber120when the first and fourth valves132,234are open to simultaneously pull any fluid contents such as the fluid140from the first expandable chamber110into the rigid chamber120proximate the first expandable chamber110and push any fluid contents such as the fluid140from the rigid chamber120proximate the expandable chamber210through the fourth semipermeable membrane224to expel the water from the implantable device200. The piston122is also configured to perform a pump-actuated push stroke in the rigid chamber120when the second and third232,134valves are open to simultaneously push any fluid contents such as the fluid140from the rigid chamber120proximate the first expandable chamber110through the third semipermeable membrane124to expel the water from the implantable device200and pull any fluid contents such as the fluid140from the second expandable chamber210into the rigid chamber120proximate the second expandable chamber210. Like the pump-actuated push stroke described in reference to the implantable device100, the foregoing pump-actuated strokes can be further utilized with timely opening and closing of the valves to push the retentate of the fluid140from the rigid chamber120into the expandable chambers110,210for additional cycles. In addition, the foregoing pump-actuated strokes can be further utilized in a cycling mode of operation like that of the implantable device100.

Each semipermeable membrane of the first, second, third, and fourth semipermeable membranes112,124,212,224of the implantable devices100and200can 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+, Ca2+, Mg2+, 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 fluid140, or osmotic fluid, within the implantable device100or200can 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 membranes112,124,212,224. The initial or basal concentration of the dissolved polymer in the fluid140is sufficient to create an osmotic potential for removing the water in excess of that the patient needs through the first semipermeable membrane112or the second semipermeable membrane212while the implanted device100or200is 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 membrane112or the second semipermeable membrane212while the implanted device100or200is implanted in the patient.

Each implantable device of the implantable device100and the implantable device200is 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 device100,200because movement of the patient allows the fluid140in the expandable chambers110,210to keep moving fluid around, thereby encouraging movement that maintains a concentration gradient that promotes osmosis. In addition, the implantable device100can 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 devices100and200are electrically powered devices, each implantable devices of the implantable device100and the implantable device200further 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.

While some particular embodiments have been disclosed herein, and while the particular embodiments have been disclosed in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts provided herein. Additional adaptations and/or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and/or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments disclosed herein without departing from the scope of the concepts provided herein.