Self-powered medical drain device

Abstract

Self-powered medical drain apparatuses and methods are disclosed. A self-powered medical drain may include a non-permeable, flexible housing filled with an expanding absorbent material. As fluid enters the drain, the expanding absorbent material expands and exerts an outward pressure on the housing. The outward pressure increases the volume of the housing thereby generating a negative pressure to draw additional fluid into the drain.

Description

SELF-POWERED MEDICAL DRAIN DEVICECLAIM OF PRIORITY

[0001] This patent application claims priority to U.S. provisional patent application no. 63 / 584,949, titled “SELF-POWERED MEDICAL DRAIN DEVICE,” filed September 25, 2023, and herein incorporated by reference in its entirety.INCORPORATION BY REFERENCE

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.FIELD

[0003] Described herein are apparatuses (e.g., devices, systems, etc.) and methods that may be used to treat a patient. Specifically, the apparatuses and methods described herein may be used to provide a negative pressure self-powered surgical drain for post-operative patients.BACKGROUND

[0004] Medical suction devices, such as surgical drains, are often used for post-operative patients to provide a means for removing pus, blood, or other fluids that may build up at or near a surgical site. These surgical drains may reduce discomfort and speed up recovery time for the patient. Negative pressure surgical drains may rely on a constant or nearly constant vacuum to draw fluids into a reservoir. In some examples, the vacuum may be supplied by an electrical motor. In other examples, such as in a hospital setting, the vacuum may be supplied by a “house vacuum” source that is provided by a central vacuum source and routed throughout the hospital.

[0005] For ambulatory patients, alternative surgical drains may be used. In one example, flexible bulb-based drains (commonly referred to as Jackson-Pratt drains) are often used to as a portable negative pressure drain device for post-operative patients. The Jackson-Pratt drains are inexpensive and lend themselves to home care. Furthermore, maintenance of the Jackson- Pratt drains is relatively simple.

[0006] These flexible bulb-based surgical drains are typically formed with a deformable (plastic) body that also functions as the reservoir. The bulb is squeezed to expel air and create a negative pressure as the bulb seeks to expand back to its original shape. These surgical drains, however, cannot provide a constant negative pressure. Oftentimes, the negative pressure decreases over time as the reservoir fills with captured fluid. The decreasing negative pressure may result in inconsistent amounts of fluid that can be withdrawn from a patient.SUMMARY OF THE DISCLOSURE

[0007] Described herein are self-powered surgical drain apparatuses and methods of using them, making them and methods of draining a surgical wound. These methods may generally include an enclosed absorbent (or super absorbent) material arranged in an enclosed, impermeable container (e.g., housing) that is configured to be primed. The absorbent material may be arranged so that once the apparatus is triggered (e.g., by applying a priming liquid) the absorption of fluid from the wound or priming fluid drives expansion and further absorption over a controlled time to allow fluid to be drained from a wound without requiring additional power or force. In some examples these apparatuses include one or more distributors (e.g., wicking distributors) within the apparatus that controllably distribute liquid so that the device expands and absorbs fluid by the application of negative pressure (suction) out of the device in a controlled manner. In general these apparatuses (e.g., systems and devices, including in particular surgical drain devices) and method described herein may include one or more innovative aspects.

[0008] For example, described herein are self-powered surgical drain apparatuses (e.g., devices and systems) that may include an input port configured to receive fluid from a surgical site, a non-permeable flexible housing coupled to the input port and configured to store the fluid, and an absorbent material enclosed by the non-permeable flexible housing, the absorbent material configured to expand when exposed to the fluid and exert an outward pressure onto inner walls of the non-permeable flexible housing, wherein the outward pressure generates a negative pressure coupled to the input port.

[0009] Any of these apparatuses may be implemented as a system. The system may include a fenestrated fluid collector configured to receive fluid from a surgical site, a tubular element including a distal end and a proximal end, wherein the fenestrated fluid collector is coupled to the distal end and a self-powered surgical drain. The self-powered surgical drain may include an input port coupled to the proximal end of the tubular element configured to receive fluid from the fenestrated fluid collector, a non-permeable flexible housing coupled tothe input port and configured to store the fluid received by the input port, and an absorbent material enclosed by the non-permeable flexible housing, the absorbent material configured to expand when exposed to the fluid and exert an outward pressure onto inner walls of the non-permeable flexible housing, wherein the outward pressure provides a negative pressure to the input port.

[0010] In some examples of the devices and systems described herein, the absorbent material may be configured to increase a volume of the non-permeable flexible housing. In some other examples, the absorbent material may be a super absorbent polymer. The super absorbent polymer may be configured to absorb at least one hundred times its weight in fluid.

[0011] In some examples of the devices and systems described herein, the absorbent material may be shaped as beads, chunks, fibers, powder, sheets, or a combination thereof. In some other examples of the devices and systems, the self-powered surgical drain may further comprise a porous liner surrounding the absorbent material and configured to provide space between the absorbent material and the non-permeable flexible housing. In some examples, the porous line may be selected from the group consisting of a non-woven bag, a woven bag, a knit bag, and a perforated polymer bag.

[0012] The self-powered surgical drain may further include a priming system configured to provide an initial negative pressure to the input port. The priming system may include a spring configured to expert an outward pressure on the non-permeable flexible housing in response to a compression of the spring. In some examples, the priming system may include a sleeve configured to maintain the spring in a compressed state until the sleeve is removed. In some examples, the priming system may include a deformable non-permeable flexible housing configured to be compressed and expand in response to the compression. The priming system may include a syringe configured to deliver fluid to the absorbent material. The priming system may include a foam block within the non-permeable flexible housing configured to be compressed and expand in response to the compression. The priming system may include a fluid-filled capsule coupled to the absorbent material and configured to be ruptured and deliver fluid to the absorbent material.

[0013] The negative pressure may be determined, at least in part, by a surface area of the absorbent material. The negative pressure may be determined, at least in part, by a rate of fluid absorption of the absorbent material. For example, the negative pressure may be determined, at least in part, by a ratio of volume expansion per unit of fluid absorbed by the absorbent material. The negative pressure may be lower than ambient pressure near the surgical site.

[0014] For example, described herein are self-powered surgical drain devices including: an input port configured to receive liquid from a surgical wound site; an expandable, non- permeable container coupled to the input port; an absorbent material within the expandable, non-permeable container, the absorbent material configured to expand when exposed to liquid from the input port and to exert an outward pressure to expand the expandable, non- permeable container resulting in a negative pressure at the input port; and a wicking distributor within the expandable, non-permeable container arranged to distribute liquid from the input port to the absorbent material.

[0015] Any appropriate absorbent material may be used, including (but not limited to) superabsorbent materials. For example, the absorbent material may be configured to expand when exposed to the liquid and exert an outward pressure of between 80 and 120 mmHg. The absorbent material may comprise a super absorbent polymer. The absorbent material may be configured to absorb at least one hundred times its weight in liquid. In some examples the absorbent material is shaped as beads, chunks, fibers, dust, sheets, or a combination thereof. The sizes of the absorbent material may be, for example, between about 0.1 mm and about 5 cm particle size (e.g., between about 0.1 mm and about 5 mm, between about 0.1 mm and about 2 mm, between about 0.1 mm and about 1 mm, between about 1 mm and 10 mm, between about 1 mm and 7mm, between about 1 mm and about 5 mm, between about 1 mm and about 2.5 mm, between about 5 mm and 3 cm, between about 5 mm and 2 cm, between about 10 mm and 5 cm, between about 2 cm and 5 cm, etc.). The size may be distributed within any of these ranges. In some examples the size is distributed so that at least 50% (e.g., at least 60%, at least 70%, at least 80%, at least 90%, etc.) of the particles are within any of these size range distributions.

[0016] The absorbent material may be, for example, may be a superabsorbent polymer (SAP) that can absorb and retain extremely large amounts of a liquid relative to its own mass. The absorbent material may be a hydrogel and may absorb aqueous solutions through hydrogen bonding with water molecules. The absorbent material may be made from a polyacrylic acid sodium salt (e.g., sodium polyacrylate), a polyacrylamide copolymer, an ethylene maleic anhydride copolymer, a cross-linked carboxymethylcellulose, a polyvinyl alcohol copolymer, a cross-linked polyethylene oxide, and / or a starch grafted copolymer of polyacrylonitrile. The absorbent material may be formed by gel polymerization, suspension polymerization or solution polymerization. The absorbent material may be a low-density cross-linked polymer, or in some examples a high cross-link density polymers.

[0017] Any of the apparatuses described herein may include a wicking distributor, as described above. In some examples the apparatus does not include a wicking distributor. Insome examples the wicking distributor is configured as a fabric bag that is at least partially holding the absorbent material. In some examples the wicking distributor is selected from the group consisting of a non-woven holder, a woven holder, a knit holder, and a perforated polymer holder. The wicking distributor may comprise a porous holder surrounding the absorbent material and configured to separate the absorbent material from the expandable, non-permeable container. Alternatively or additionally, in some examples the wicking distributor extends through the absorbent material.

[0018] Any of the apparatuses descried herein may include one or more mechanical primers configured to provide an initial negative pressure at the input port. The mechanical primer may comprise a spring configured to be released to exert an outward pressure on the expandable, non-permeable container in response to a compression of the spring. The mechanical primer may at least partially expand the container (the expandable, non- permeable container). For example, the mechanical primer may comprise a squeeze bulb or syringe. In some examples the mechanical primer comprises a foam block within the expandable, non-permeable container configured to be compressed and to self-expand when released from compression. Any of these apparatuses may include a retainer configured to maintain the mechanical primer in a compressed state until the retainer is removed.

[0019] Any of the apparatuses may include a fluid primer including a liquid-filled in fluid communication with the expandable, non-permeable container and configured to be activated to deliver liquid to the absorbent material.

[0020] In general, the negative pressure may be determined, at least in part, by a surface area of the absorbent material. For example, the negative pressure may be determined, at least in part, by a rate of liquid absorption of the absorbent material. The negative pressure may be determined, at least in part, by a ratio of volume expansion per unit of liquid absorbed by the absorbent material. The negative pressure may be lower than ambient pressure near the surgical wound site.

[0021] Any of these apparatuses may include one or more check valves in fluid communication with the input port.

[0022] For example, a self-powered surgical drain device may include: an input port configured to receive liquid from a surgical wound site; a check valve in fluid communication with the input port; an expandable, non-permeable container coupled to the input port and configured to hold liquid received by the input port; an absorbent material within the expandable, non-permeable container, the absorbent material configured to expand when exposed to the liquid and exert an outward pressure to expand the expandable, non-permeable container resulting in a negative pressure at the input port; and a wicking distributor withinthe expandable, non-permeable container arranged to distribute liquid from the input port to the absorbent material.

[0023] A self-powered surgical drain device may include: an input port configured to receive liquid from a surgical wound site; a check valve in fluid communication with the input port; an expandable, non-permeable container coupled to the input port and configured to hold liquid received by the input port; a superabsorbent material within the expandable, non-permeable container, the superabsorbent material configured to expand when exposed to the liquid and exert an outward pressure of between about 80 and 120 mmHg to expand the expandable, non-permeable container resulting in a negative pressure at the input port; and a wicking distributor at least partially enclosing the superabsorbent material in a porous holder.

[0024] Also described herein are methods of removing fluid from a body region (including but not limited to a surgical site). For example, a method (such as, but not limited to a method for supplying a negative pressure to a wound site) may include: priming a self- powered surgical drain to begin a flow of a liquid from a wound site into the self-powered surgical drain; contacting a superabsorbent material within an inner volume of an expandable, non-permeable container of the self-powered surgical drain with the liquid, so that the superabsorbent material expands the expandable, non-permeable container and creates a negative pressure an input port of the expandable, non-permeable container; and sustaining a negative pressure as liquid is drawn into the superabsorbent material to expand the expandable, non-permeable container as the superabsorbent material expands over time.

[0025] Any of these methods may include wicking the liquid to distribute it to the superabsorbent material. Any of these methods may include coupling a sealable wound covering in fluid communication with the input port. For example a method may include coupling a sealable wound covering in fluid communication with the input port after priming the self-powered surgical drain. Priming the self-powered surgical drain may comprise applying a mechanical force to at least partially expand the inner volume of the expandable, non-permeable container.

[0026] Applying the mechanical force may comprise at least partially compressing a bias coupled to the expandable, non-permeable container and allowing it to expand and draw fluid through the input port and into the superabsorbent material to begin expansion of the superabsorbent material.

[0027] In some examples priming comprises adding a liquid to superabsorbent material to begin expansion of the superabsorbent material and thereafter the expandable, non-permeable container.

[0028] In any of these examples, sustaining the negative pressure may comprise sustaining the negative pressure between about 80 and 120 mmHg. For example, sustaining may comprise sustaining for more than 12 hours.

[0029] The method may include blocking outflow out of the expandable, non-permeable container.

[0030] Any of the apparatuses described herein may be configured as a system. Thus, any of these systems may include a sealable wound covering and any of the self-powered surgical drain devices as described herein. For example, a system may include: a sealable wound covering including an output port; a self-powered surgical drain device including: an input port configured to be secured in fluid communication with the output port of the sealable wound covering; an expandable, non-permeable container coupled to the input port; an absorbent material within the expandable, non-permeable container, the absorbent material configured to expand when exposed to liquid from the input port and to exert an outward pressure to expand the expandable, non-permeable container resulting in a negative pressure at the input port; and a wicking distributor within the expandable, non-permeable container arranged to distribute liquid from the input port to the absorbent material.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Novel features of examples described herein are set forth with particularity in the appended claims. A better understanding of the features and advantages of the examples may be obtained by reference to the following detailed description that sets forth illustrative examples and the accompanying drawings.

[0032] FIG. 1 depicts one example of a surgical drain system.

[0033] FIGS. 2A-2B show front and side views, respectively, of one example of a self- powered surgical drain device in an initial stage.

[0034] FIGS. 2C-2D show front and side views, respectively, of the self-powered surgical drain device of FIG. 2 A in an intermediate stage.

[0035] FIGS. 2E-2F show front and side views, respectively, of the self-powered surgical drain device of FIG. 2 A in a completed stage.

[0036] FIGS. 3A-3C show front, side and top views (respectively) of another example of a self-powered surgical drain device in an initial stage.

[0037] FIGS. 3D-3F show front, side and top views (respectively) of the self-powered surgical drain device of FIG. 3 A in a first intermediate stage.

[0038] FIGS. 3G-3I show front, side and top views (respectively) of the self-powered surgical drain device of FIG. 3 A in a second intermediate stage.

[0039] FIGS. 3J-3K show front and side views (respectively) of the self-powered surgical drain device of FIG. 3 A in a completed stage.

[0040] FIG. 4 shows another example of a self-powered surgical drain device.

[0041] FIG. 5A shows another example of a self-powered surgical drain device.

[0042] FIG. 5B shows another example of a self-powered surgical drain device.

[0043] FIG. 5C shows another example of a self-powered surgical drain device.

[0044] FIG. 6 shows another example of a self-powered surgical drain device.

[0045] FIG. 7 shows another example of a self-powered surgical drain device.

[0046] FIGS. 8A-8C illustrate another example of a self-powered surgical drain device showing a top view (FIG. 8A) a first side view (FIG. 8B, not yet activated) and a second side view (FIG. 8C, activated).

[0047] FIGS. 9A-9C illustrate another example of a self-powered surgical drain device, including an internal wicking distributor extending through the absorbent material, as well as within the absorbent material, showing a top view (FIG. 9A) a first side view (FIG. 9B, not yet activated) and a second side view (FIG. 9C, activated).

[0048] FIGS. 10A and 10B shows an example of a prototype device absorbing fluid from a water bath.

[0049] FIG. 11 A shows another example of a prototype self-powered surgical drain device. FIG. 1 IB shows a side view of the prototype device of FIG. 11 A. FIG. 11C illustrates priming the example prototype device shown in FIG. 11 A.

[0050] FIG. 12 illustrates one example of a system including a self-powered surgical drain device and a dressing that may be coupled to the self-powered drain device to apply negative pressure over time to remove fluid from a wound.

[0051] FIG. 13 is a graph 800 comparing negative pressure curves associated with conventional surgical drains and the self-powered surgical drain devices described herein.DETAILED DESCRIPTION

[0052] Medical suction devices, such as portable surgical drains, are often used by ambulatory patients that can benefit from the draining of fluids that result from a wound, a surgical procedure, or other medical treatment. Some portable surgical drains may provide negative pressure to assist in the withdrawal and collection of bodily fluids. However, the provided negative pressure may be inconsistent and may fluctuate as fluids are collected.

[0053] Examples of the subject matter disclosed in this disclosure may include a self- powered surgical drain configured to provide a near constant negative pressure. The negative pressure may be provided by expanding absorbent material that expands as bodily fluids areabsorbed. The expanding absorbent material may cause a housing of the self-powered surgical drain to expand and generate a negative pressure to pull bodily fluids from the patient. In some examples the absorbent material may include super absorbent polymers. In some other examples, the self-powered surgical drain may include a priming system to provide an initial negative pressure until fluids are available to the absorbent material.

[0054] Some examples of the subject matter described in this disclosure can realize one or more of the following potential advantages. In some examples, a self-powered surgical drain may provide a more constant negative pressure to a patient compared to conventional surgical drains. The more constant negative pressure may provide a more effective surgical drain that may enhance post-operative healing for a patient.

[0055] FIG. 1 depicts one example of a surgical drain system 100 applied to a subject (e.g. patient) 110. As shown, the surgical drain system 100 may include a self-powered surgical drain device 120, an elongate tube 121, and a fenestrated fluid collector 122. The fluid collector may be used with and / or may be part of a dressing, bandage, cast, brace, etc. and / or may be implanted within the subject. The surgical drain system 100 may be used with a patient 110. For example, the fenestrated fluid collector 122 may be coupled to the elongate tube and surgically implanted within or adjacent to a wound site, such as a surgical site. The fenestrated fluid collector 122 is just one example of a patient interface and may be optional; in some examples the self-powered surgical drain device may be coupled directly to a patient and / or dressing (e.g., bandage, etc.). In some examples the self-powered surgical drain device may be connected to a patient interface comprising a porous material, through which it may apply negative pressure.

[0056] The elongate tube 121 may be coupled to the self-powered surgical drain device and / or may be coupled between a fenestrated fluid collector 122 and the self-powered surgical drain device 120. For example, a distal end of the elongate tube 121 may be coupled to the fenestrated fluid collector 122 and a proximal end of the elongate tube 121 may be coupled to the self-powered surgical drain device 120. (The distal and proximal descriptors are with respect to the self-powered surgical drain device 120.) The self-powered surgical drain device 120 may provide a reservoir for receiving and storing fluid from the wound site 115. The self-powered surgical drain device 120 may also provide a negative pressure to the wound site 115 through the elongate tube 121 and the fenestrated fluid collector 122. Negative pressure may refer to any pressure that is less than a reference pressure. For example, in the case of surgical drains, a negative pressure may be a pressure at the surgical drain that is less than an ambient pressure at or near a surgical site.

[0057] In some examples, the self-powered surgical drain device 120 may include a housing and a highly absorbent material. The housing may be formed as non-permeable pouch and may be formed from any feasible material. Such material may include polymers such as polyurethane or polyethylene of other sealable air tight / water tight material. In some examples, the highly absorbent material may be a super absorbent polymer or any other feasible material capable of absorbing fluid and expanding in volume. Some examples of self-powered surgical drain devices are described below in conjunction with FIGS. 2A-7.

[0058] FIGS. 2A-2B shows front and side views, respectively, of one example of a self- powered surgical drain device 200 in an initial stage. The self-powered surgical drain device 200 may include a housing 210, an input port 220, and an expanding absorbent material 230. The absorbent material 230 may be held within a wicking distributor, configured as a bag in FIGS. 2A-2B, within the expandable non-permeable container 210. Although shown in FIGS. 2A-2F as rectangular in shape, the housing 210 may have any feasible shape and large crosssection, including but not limited to oval, circular, square, or polygonal. The housing 210 may be formed of any feasible flexible non-permeable material. For example, the housing 210 may be a polymer such as a thermoplastic, a thermoset, an elastomer, and / or a synthetic fiber. The housing 210 may act as a reservoir for fluid to be stored by the self-powered surgical drain device 200. The housing may be configured to collapse and expand, e.g., accordion-like.

[0059] The input port 220 may be part of and / or coupled to the housing 210. The housing 210 may be sealed (e.g., airtight) except for the input port 220. The input port 220 may have any feasible shape and may be otherwise well-suited to couple and / or attach to any feasible elongate tubing. For example, the input port 220 may be coupled to surgical tubing that is, in turn, coupled to a fenestrated fluid collector that may be implanted into a patient’s body (tubing and fenestrated fluid collector not shown for simplicity). The expanding absorbent material 230 may be any feasible absorbent material that expands in volume as fluid is absorbed. In some examples, the expanding absorbent material 230 may be a super absorbent polymer that absorbs approximately 300 times its weight in fluid. In some cases, a super absorbent polymer may absorb less than 300 times its weight, such as, but not limited to, 50, 75, or 100 times its weight.

[0060] In the initial stage (shown in FIG. 2 A), the housing 210 may have a first (initial) volume. Furthermore, the expanding absorbent material 230 may be dry and relatively compressed. Thus, the volume displaced by the housing 210 may be a minimum. As the expanding absorbent material 230 absorbs fluid, the expanding absorbent material 230 may expand, provide outward pressure to the housing 210, and increase the volume of the housing210. The increased volume may create a negative pressure (e.g., vacuum) though the input port 220 that may be used to help drain fluid from a surgical wound site.

[0061] FIGS. 2C-2D show front and side views, respectively, of the self-powered surgical drain device 200 in an intermediate stage. In the intermediate stage, the negative pressure at the input port 220 generated during and / or after the initial stage has caused fluid to flow into the housing 210, wetting the absorbent material and causing it to expand. Some of the expanding absorbent material 230 has absorbed the fluid and become saturated absorbent material 231. The saturated absorbent material 231 may expand as fluid is absorbed. As the saturated absorbent material 231 expands, the volume of the housing 210 increases. The increased volume provides and / or generates a negative pressure at the input port 220. In this manner, a negative pressure may constantly be generated as fluid is introduced and stored within the housing 210.

[0062] FIGS. 2E-2F show front and side views, respectively, of the self-powered surgical drain device 200 in a completed stage. In the completed stage, the expanding absorbent material 230 may be substantially replaced by the saturated absorbent material 231. The housing 210 may have expanded to a maximum volume. The side view shows the walls of the housing 210 bowed outward to accommodate the expanded saturated absorbent material 231. In the completed stage, the saturated absorbent material 231 may be “depleted” and no longer be able to absorb any more fluid. Thus, negative pressure may no longer be available at the input port 220.

[0063] In some cases, to transition from the initial stage shown in FIG. 2A, the self- powered surgical drain device 200 may include a priming system to provide an initial negative pressure to the input port 220. In one example of a priming system, an initial volume of liquid may be introduced to the expanding absorbent material 230, thereby causing expansion and a generation of negative pressure. For example, a syringe (not shown) may be used to deliver a volume of liquid to the otherwise dry expanding absorbent material 230. A portion of the expanding absorbent material 230 may become saturated absorbent material 231 that expands and increases in volume. Thus, the saturated absorbent material 231 may provide an outward pressure to the inner walls of the housing 210 which, in turn, may generate a negative pressure that is provided to the input port 220. The negative pressure may draw fluid from the patient into the housing 210 and the expanding absorbent material 230. In response, the expanding absorbent material 230 becomes saturated absorbent material 231, expands and generates more negative pressure that can draw more fluid from the patient. In some examples, the negative pressure may be determined by a ratio of volume expansion per unit of fluid absorbed by the expanding absorbent material 230. For example, a relativelygreater negative pressure may be associated with an expanding absorbent material 230 that expands to a volume much greater than the fluid it absorbs (e.g., a ratio of volume expansion to fluid absorbed being much greater than one). On the other hand, a relatively lesser negative pressure may be associated with an expanding absorbent material 230 that expands to a volume much closer to the volume fluid it absorbs (e.g., a ratio of volume expansion to fluid absorbed being closer to one).

[0064] In another example, a liquid filled capsule (not shown) may be included with the expanding absorbent material 230. To transition from the initial stage, a user (medical provider, clinician, patient, or the like) may rupture the capsule releasing the liquid into the expanding absorbent material 230. As the expanding absorbent material 230 becomes saturated absorbent material 231, the saturated absorbent material 231 expands and provides outward pressure to the housing 210. The outward pressure may cause the housing 210 to expand and provide negative pressure to the input port 220. The negative pressure may draw fluid from the patient into the housing 210 and the expanding absorbent material 230. In response, the expanding absorbent material 230 becomes saturated absorbent material 231, expands and generates additional negative pressure that can draw more fluid from the patient.

[0065] In other examples, a mechanical device may be used to provide an initial outward pressure to the housing and thereby generate an initial negative pressure. One example of such a priming system described below with respect to FIGS. 3 A-3K.

[0066] FIGS. 3A-3C show front, side and top views, respectively, of another example of a self-powered surgical drain device 300 in an initial stage. The initial stage may also be referred to as the undeployed state. The self-powered surgical drain device 300 may include a housing 310, an input port 320, an expanding absorbent material 330, a wicking distributor 355 and a spring member 340. The housing 310, the input port 320, and the expanding absorbent material 330 may be other examples of the housing 210, the input port 220, and the expanding absorbent material 230 of FIG. 2, respectively. For example, the expanding absorbent material 330 may be a super absorbent polymer as described above with respect to FIG. 2A-2F. The wicking distributor in this example is an outer, permeable bag or envelope that is configured to distribute fluid from the port 320 into the absorbent material more uniformly. The wicking distributor may help maintain the negative pressure by allowing the fluid to be disturbed over time through (and / or around) the absorbent material.

[0067] The spring member 340 may be coupled and / or attached to the housing 310. The spring member 340 may provide an initial outward force to the housing 210 that may provide an initial negative pressure to the input port 320. Thus, in some examples, the spring member 340 may help prime the self-powered surgical drain device 300.

[0068] In the initial stage, the housing 310 may be biased to an expanded state by the spring member 340. In some examples, the spring member 340 may be coupled or attached to the outside of the housing 310. In some other examples, the spring member 340 may be coupled or attached to the inside of the housing 310. Although depicted here as a flat spring, the spring member 340 may be any feasible shape and formed from any feasible material. In the initial stage, the expanding absorbent material 330 may be dry and relatively compressed.

[0069] FIGS. 3D-3F show front, side and top views of the self-powered surgical drain device 300 in a first intermediate stage. The first intermediate stage may also be referred to as a priming stage. In the first intermediate stage, the spring member 340 (also referred to herein as a priming region or element) and the housing 310 are compressed to expel air and prepare the input port 320 to receive fluid from the patient. After coupling to the input port 320 to a patient, the spring member 340 may be released and allowed to expand. In some examples, the spring member 340 may be maintained in a compressed state by a sleeve, clip, or other feasible restriction device until the self-powered surgical drain device 300 is ready to use. Then, to initiate negative pressure at the input port 320, the user or clinician simply removes the sleeve, clip, or other restriction device. In this example the device is manually primed by compressing the priming region (spring member 340).

[0070] The expansion of the spring member 340 may provide outward pressure to the housing 310 which provides a negative pressure to the input port 320. The negative pressure can draw fluid from the patient into the expanding absorbent material 330.

[0071] FIGS. 3D-3F show front, side and top views of the self-powered surgical drain device 300 in a second intermediate stage (priming stage). In the second intermediate stage, the negative pressure generated by compressing the device from the first intermediate stage has drawn fluid into the housing 310 and the expanding absorbent material 330. As a result, some of the expanding absorbent material 330 has become saturated absorbent material 331 and expanded against the housing 310. Thus, the expanding saturated absorbent material 331 may generate additional negative pressure at the input port 320. Furthermore, the spring member 340 may also continue to exert outward pressure to the housing 310. The outward pressure from the spring member 340 may provide negative pressure at the input port 320 alternatively to or in addition with the negative pressure from the expanding saturated absorbent material 331. As shown in FIGS. 3G-3I, additional expanding absorbent material 330 is still available to receive and absorb fluid from the patient.

[0072] FIGS. 3J-3K shows front and side views of the self-powered surgical drain device in a completed stage. In the completed stage, the expanding absorbent material 330 may be substantially replaced by the saturated absorbent material 331. The housing 310 has expandedto a maximum volume. The side view shows the walls of the housing 310 bowed outward to accommodate the expanded saturated absorbent material 331. In the completed stage, the saturated absorbent material 331 may be depleted and no longer be able to absorb any more fluid. Thus, negative pressure may no longer be available at the input port 320.

[0073] In some examples, instead of the spring member 340, the self-powered surgical drain device 300 may include a compressible foam or sponge that is positioned within the housing 310 (not shown). Similar to the spring member 340, the compressible foam or sponge may be compressed and as the foam or sponge expands after the compression, an outward pressure is exerted on the housing 310 generating a negative pressure at the input port 320.

[0074] In another example, the housing 310 may be deformable and compressible, similar to some conventional surgical drains. However, in contrast to conventional housings, the housing 310 may be filled with the expanding absorbent material 330. In some examples, to provide an initial negative pressure the user may compress the housing 310. As the housing 310 expands (responding to the compression), an initial negative pressure may be provided at the input port 320. This negative pressure may draw fluid into the housing 310 and the expanding absorbent material 330. The expanding absorbent material 330 may saturate, expand, and provide continuing negative pressure.

[0075] As described above, the expanding absorbent material may be a super absorbent polymer. Moreover, the expanding absorbent material, may have a variety of physical shapes. In some cases, shapes that have more surface area for a given volume may have a relatively faster fluid absorption rate and, therefore, may react faster to incoming fluid. On the other hand, shapes that have less surface area for a given volume may have a relatively slower fluid absorption rate which may provide increased outward force and a slower reaction to incoming fluid. The fluid absorption rate may be directly proportional to the expansion rate of the saturated absorbent material 331 and, therefore, directly proportional to the generated negative pressure.

[0076] Furthermore, a reliable supply of negative pressure from the self-powered surgical drain devices may be dependent on the ability of the expanding absorbent material to have reliable access to incoming fluid. That is, the expanding absorbent material should be protected from clogs or other blockages. In some cases, as the expanding absorbent material expands, the material may block fluid flow within the housing.

[0077] FIG. 4 shows another example of a self-powered surgical drain device 400 that may include a housing 410, an input port 420, expanding absorbent material 430, a spring member 440, and a porous liner (wi eking distributor) 450. The housing 410, input port 420,expanding absorbent material 430, and spring member 440 may be examples of the housing 310, input port 320, expanding absorbent material 330, and spring member 340 of FIGS. 2A- 2F and 3A-3K described above.

[0078] The wicking distributor, show as a porous liner 450 in FIG. 4 (which may be optionally included with any self-powered surgical drain device described herein) may help prevent the expanding absorbent material 430 from expanding and blocking the flow of fluid particularly near the input port 420 and between the expanding absorbent material 430 and / or the housing 410. For example, the wicking distributor 450 may physically separate the expanding absorbent material 430 from the housing 410, effectively providing a space for fluid to travel within the housing 410 and reach multiple areas of the expanding absorbent material 430. In FIG. 4 the porous liner 450 is depicted here with a dotted line. The porous liner 450 may completely or partially encompass and / or surround the expanding absorbent material 430.

[0079] In some examples, the wicking distributor 450 may take the form of a pouch, bag, or any other feasible form that can surround and / or extend within the expanding absorbent material 430. In some examples, the wicking distributor 450 may be formed from a woven material, a non-woven material, a knit material, a perforated polymer material, or any other technically feasible material. In some examples, the wicking distributor 450 may be shaped to direct expansion of the expanding absorbent material 430. For example, the wicking distributor 450 may be shaped to force the expanding absorbent material 430 to expand in a profile similar to an overall shape of the housing 410.

[0080] In some other examples, an optional tube 460 may be route fluid from the input port 420 into a region (e.g., in some examples a central region) within the expanding absorbent material 430. In still other examples, a wicking distributor (e.g., a wick, not shown) may extend within the absorbent material and / or around the absorbent material. In some examples the wicking distributor may be a wick within the absorbent material that extends from or replaces the tube 460. Thus, the tube 460 (or wick) may help distribute the fluid drawn into the housing 410 within the expanding absorbent material 430. Although shown here in conjunction with the self-powered surgical drain device 400, the tube 460 (or wick) may be included with any feasible implementation of a self-powered surgical drain.

[0081] In some examples, the expanding absorbent material 430 may be shaped like very fine particles, such as, for example, powder and / or dust sized particles. Fine particles may have a higher surface area to volume ratio that may enable a more rapid absorption of fluid compared to particles with a lower surface area to volume ratio. A rapid absorption rate mayenable the self-powered surgical drain device 400 to provide a relatively greater negative pressure than self-powered surgical drain devices with a lower absorption rate.

[0082] In another example, the expanding absorbent material 430 may be shaped or formed like sheets. Thus, the expanding absorbent material 430 may include one or more sheets that may be enclosed or surrounded by the porous liner 450. Sheets may be less likely to clog or restrict fluid flow within the housing 410.

[0083] FIGS. 5A-5C shows other examples of self-powered surgical drain devices 500 that may include a housing 510, an input port 520, expanding absorbent material 530, a spring member 540, and a wicking distributor 550. The housing 510, input port 520, expanding absorbent material 530, spring member 540, and the wicking distributor 550 may be other examples of the housing 410, input port 420, expanding absorbent material 430, spring member 440, and the wicking distributor 450 of FIG. 4, respectively.

[0084] In some examples, the expanding absorbent material 530 may be shaped. For example, the absorbent material may be shaped like spheres or balls as shown in FIGS. 5A and 5C. The spherical shape of the expanding absorbent material 530 may enable fluid to more easily penetrate the volume of the expanding absorbent material 530 without clogging or restricting fluid flow. The optional wicking distributor 550 may also aid in fluid flow within the housing 510 and throughout the expanding absorbent material 530. The shape of the absorbent material may be configured to pack within the apparatus while still allowing fluid to flow in through the port and to expand the non-permeable container 610. In any of these examples the absorbent material may be shaped to include channels or passage for water to pass, wick or other was extend while maximizing the expansion of the non- permeable container.

[0085] FIG. 6 shows another example of a self-powered surgical drain device 600 that may include a housing 610, an input port 620, expanding absorbent material 630, a spring member 640, and a wicking distributor 650. The housing 610, input port 620, expanding absorbent material 630, spring member 640, and the wicking distributor 650 may be other examples of the housing 410, input port 420, expanding absorbent material 430, spring member 440, and the porous liner 450 of FIG. 4, respectively.

[0086] In some examples, the expanding absorbent material 630 may be configured as irregularly-shaped (in some examples, randomly shaped) chunks. The chunks may vary in size and shape. For example, the average size or volume of the chunks may vary. The chunks may have smooth, rugged, and / or jagged surfaces. The varied sizes, shapes, and surfaces of the chunks may also enable fluid to more easily penetrate the volume of the expanding absorbent material 630 without clogging or otherwise restricting fluid flow. The optionalporous liner 650 may also aid in fluid flow within the housing 610 and throughout the expanding absorbent material 630.

[0087] FIG. 7 shows another example of a self-powered surgical drain device 700 that may include a housing 710, an input port 720, expanding absorbent material 730, a spring member 740, and a wicking distributor 750. The housing 710, input port 720, expanding absorbent material 730, spring member 740, and the wicking distributor 750 may be other examples of the housing 410, input port 420, expanding absorbent material 430, spring member 440, and the porous liner 450 of FIG. 4, respectively. In some examples, the expanding absorbent material 730 may be shaped like fibers. The fibers may have inter-fiber spaces that allow fluid to easily be absorbed throughout the fibers while resisting clogging or other blockages.

[0088] FIGS. 8A-8C illustrate the operation of another example of a self-powered surgical drain device. In FIG 8A, the device includes an input port / drain connector 851. A check valve 853 (one-way valve) prevents flow of fluid out of the device. Any appropriate check valve may be used (e.g., flap valve, ball valve, etc.). The device also includes an expandable, non-permeable container 855 coupled to the input port, and an absorbent material 857 held within a wicking distributor 859 (shown as a permeable textile “bag”) within the expandable non-permeable container. In FIG. 8A the device is shown in a ready- to-use, pre-deployed configuration. FIG. 8B shows the device of FIG. 8 A from a side view.

[0089] FIG. 8C shows another side view of the device of FIG. 8 A, showing the device during operation, after priming, when fluid is being drawn into 861 the device as it expands outwards 863 in a positive-feedback loop; once fluid is drawn into the container 855 through the port 851 so that it contacts and is absorbed by the absorbent material 857, causing it to swell and push outward 863 against the container 855, driving further negative pressure and drawing additional fluid into the device.

[0090] FIGS. 9A-9C illustrate another example of an apparatus similar to that shown in FIG. 8A-8C. In this example the apparatus includes an internal wicking distributor 958 extending through the absorbent material 957 within the expandable, non-permeable container 955. A separate wicking distributor, configured as a bag 959 encloses the absorbent material. In FIG. 9A, the internal wicking distributor 958 is shown as a branching structure that extends throughout or within the absorbent material. This may allow uniform distribution of fluid from 961 out of the input port 951, through the check valve 953. In FIG. 9C the device is shown in an expanded configuration, having absorbed a volume of fluid driving expansion 963 of the container. The arbors of internal wicking distributor 958 help more uniformly distribute the fluid.

[0091] FIGS. 10A-10B illustrate one example of a prototype device including an expandable non-permeable container that encloses an absorbent material, shown as a plurality of spherical superabsorbent material spheres 1004. This device is shown placed within a fluid-filled (water) bath 1008, and allowed to draw fluid up into the bag 1010 over time (over many hours) as the port 1006 into the inner chamber is opened in contact with the liquid in the bath. Swelling of the beads (spheres 1004), as shown in FIG. 10B, results in expansion of the container, and draws fluid into the container even against gravity, to swell the hydrogel absorbent material.

[0092] FIGS. 11A-11C illustrate another example of a self-powered surgical drain device similar to that shown in FIGS. 2A-2F and 3A-3K. In FIG. 11 A the apparatus includes an input port 1105 configured to receive liquid (e.g., from a surgical wound site). This example includes a pair of ports 1105, 1105’. The second port may be connected to a source of vacuum (e.g., for priming and / or clearing the device) and / or to a source of fluid, for starting / initiating / priming the device. The device includes an expandable, non-permeable container 1107 coupled to the input port. The container is formed of a polymeric material, an encloses a wi eking distributor 1113 formed of a porous material (shown as a bag or sheet of material) adjacent to or enclosing an absorbent material (not visible) within the expandable, non-permeable container. FIG. 1 IB shows a side view of the device.

[0093] To initiate suction into the device, a user may manually apply force to compress the device, as shown in FIG. 11C. In this example, the device includes a mechanical primer 1115 configured to provide an initial negative pressure at the input port. The mechanical primer provides a spring force that drives expansion of the container 1107, pulling fluid into the device. The mechanical primer is configured to be released to exert an outward pressure on the expandable, non-permeable container in response to a compression of the spring-like mechanical body.

[0094] FIG. 12 shows an example of a system including a patient interface (shown here configured as a bandage or dressing) 1209 that is connected via a tubing 1213 to a self- powered surgical drain device 1200 including a housing (container 1205) enclosing an absorbent material 1207 that may swell when in contact with fluid from out of the tube. The system may be coupled to the patient and primed, e.g., by squeezing to apply negative pressure as shown in FIG. 11C.

[0095] FIG. 13 is a graph 800 comparing negative pressure curves associated with conventional surgical drains and the self-powered surgical drain devices described herein. As described herein, conventional surgical drains may provide a decreasing negative pressure as more fluid is extracted and stored within the surgical drain reservoir. For example, when aconventional surgical drain is initially connected to a patient, a negative pressure exceeding 75 centimeters (cm) of water (H2O) may be provided. As fluid is collected in the reservoir, negative pressure decreases. As shown, when the conventional surgical drain has collected 25 milliliters (ml), the negative pressure is below 75 cm H2O. Negative pressure continues to fall as more fluid is collected. This trend is shown with conventional negative pressure curve 810.

[0096] In contrast, the self-powered surgical drain devices described herein may provide a more constant negative pressure, even as fluid is collected and stored. This near constant negative pressure is depicted by the optimized negative pressure curve 820. In some examples, any of the self-powered surgical drains described herein may provide a more constant negative pressure compared to conventional surgical drains. The more constant negative pressure may provide a more effective surgical drain that may enhance postoperative healing and possibly reduce recovery time for a patient.

[0097] When a feature or element is herein referred to as being "on" another feature or element, it can be directly on the other feature or element or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being "connected", "attached" or "coupled" to another feature or element, it can be directly connected, attached, or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected", "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

[0098] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ".

[0099] Spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly", "downwardly", "vertical", "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[0100] Although the terms “first” and “second” may be used herein to describe various features / elements (including steps), these features / elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another feature / element. Thus, a first feature / element discussed below could be termed a second feature / element, and similarly, a second feature / element discussed below could be termed a first feature / element without departing from the teachings of the present invention.

[0101] Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising” means various components can be co-jointly employed in the methods and articles (e.g., compositions and apparatuses including device and methods). For example, the term “comprising” will be understood to imply the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.

[0102] In general, any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and / or steps may alternatively be exclusive and may be expressed as “consisting of’ or alternatively “consisting essentially of’ the various components, steps, sub-components, or sub-steps.

[0103] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word "about" or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and / or position to indicate that the value and / or position described is within a reasonable expected range of values and / or positions. For example, a numeric value may have a value that is + / - 0.1% of the stated value(or range of values), + / - 1% of the stated value (or range of values), + / - 2% of the stated value (or range of values), + / - 5% of the stated value (or range of values), + / - 10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value unless the context indicates otherwise. For example, if the value " 10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X" is disclosed the "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0104] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments one or more method steps may be skipped altogether. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

[0105] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments havebeen illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

Claims

CLAIMSWhat is claimed is:

1. A self-powered surgical drain device, the device comprising: an input port configured to receive liquid from a surgical wound site; an expandable, non-permeable container coupled to the input port; an absorbent material within the expandable, non-permeable container, the absorbent material configured to expand when exposed to liquid from the input port and to exert an outward pressure to expand the expandable, non- permeable container resulting in a negative pressure at the input port; and a wicking distributor within the expandable, non-permeable container arranged to distribute liquid from the input port to the absorbent material.

2. The device of claim 1, wherein the absorbent material is configured to expand when exposed to the liquid and exert an outward pressure of between 80 and 120 mmHg.

3. The device of claim 1, wherein the wicking distributor comprises a fabric bag at least partially holding the absorbent material.

4. The device of claim 1, wherein the wicking distributor is selected from the group consisting of a non-woven holder, a woven holder, a knit holder, and a perforated polymer holder.

5. The device of claim 1, wherein the wicking distributor comprises a porous holder surrounding the absorbent material and configured to separate the absorbent material from the expandable, non-permeable container.

6. The device of claim 1, wherein the wicking distributor extends through the absorbent material.

7. The device of claim 1, wherein the absorbent material comprises a super absorbent polymer.

8. The device of claim 1, wherein the absorbent material is configured to absorb at least one hundred times its weight in liquid.

9. The device of claim 1, wherein the absorbent material is shaped as beads, chunks, fibers, dust, sheets, or a combination thereof.

10. The device of claim 1, further comprising a mechanical primer configured to provide an initial negative pressure at the input port.

11. The device of claim 10, wherein the mechanical primer comprises a spring configured to be released to exert an outward pressure on the expandable, non-permeable container in response to a compression of the spring.

12. The device of claim 10, further comprising a retainer configured to maintain the mechanical primer in a compressed state until the retainer is removed.

13. The device of claim 10, wherein the mechanical primer comprises a squeeze bulb or syringe.

14. The device of claim 10, wherein the mechanical primer comprises a foam block within the expandable, non-permeable container configured to be compressed and to self-expand when released from compression.

15. The device of claim 1, further comprising a fluid primer including a liquid-filled in fluid communication with the expandable, non-permeable container and configured to be activated to deliver liquid to the absorbent material.

16. The device of claim 1, wherein the negative pressure is determined, at least in part, by a surface area of the absorbent material.

17. The device of claim 1, wherein the negative pressure is determined, at least in part, by a rate of liquid absorption of the absorbent material.

18. The device of claim 1, wherein the negative pressure is determined, at least in part, by a ratio of volume expansion per unit of liquid absorbed by the absorbent material.

19. The device of claim 1, wherein the negative pressure is lower than ambient pressure near the surgical wound site.

20. The device of claim 1, further comprising a check valve in fluid communication with the input port.

21. A self-powered surgical drain device, the device comprising: an input port configured to receive liquid from a surgical wound site; a check valve in fluid communication with the input port;an expandable, non-permeable container coupled to the input port and configured to hold liquid received by the input port; an absorbent material within the expandable, non-permeable container, the absorbent material configured to expand when exposed to the liquid and exert an outward pressure to expand the expandable, non-permeable container resulting in a negative pressure at the input port; and a wicking distributor within the expandable, non-permeable container arranged to distribute liquid from the input port to the absorbent material.

22. A self-powered surgical drain device, the device comprising: an input port configured to receive liquid from a surgical wound site; a check valve in fluid communication with the input port; an expandable, non-permeable container coupled to the input port and configured to hold liquid received by the input port; a superabsorbent material within the expandable, non-permeable container, the superabsorbent material configured to expand when exposed to the liquid and exert an outward pressure of between about 80 and 120 mmHg to expand the expandable, non-permeable container resulting in a negative pressure at the input port; and a wicking distributor at least partially enclosing the superabsorbent material in a porous holder.

23. A method for supplying a negative pressure to a wound site, the method comprising: priming a self-powered surgical drain to begin a flow of a liquid from a wound site into the self-powered surgical drain; contacting a superabsorbent material within an inner volume of an expandable, non-permeable container of the self-powered surgical drain with the liquid, so that the superabsorbent material expands the expandable, non-permeable container and creates a negative pressure an input port of the expandable, non- permeable container; and sustaining a negative pressure as liquid is drawn into the superabsorbent material to expand the expandable, non-permeable container as the superabsorbent material expands over time.

24. The method of claim 23, further comprising wicking the liquid to distribute it to the superabsorbent material.

25. The method of claim 23, further comprising coupling a sealable wound covering in fluid communication with the input port.

26. The method of claim 23, further comprising coupling a sealable wound covering in fluid communication with the input port after priming the self-powered surgical drain.

27. The method of claim 23, wherein priming the self-powered surgical drain comprises applying a mechanical force to at least partially expand the inner volume of the expandable, non-permeable container.

28. The method of claim 27, wherein applying the mechanical force comprises at least partially compressing a bias coupled to the expandable, non-permeable container and allowing it to expand and draw fluid through the input port and into the superabsorbent material to begin expansion of the superabsorbent material.

29. The method of claim 23, wherein priming comprises adding a liquid to superabsorbent material to begin expansion of the superabsorbent material and thereafter the expandable, non-permeable container.

30. The method of claim 23, wherein sustaining the negative pressure comprises sustaining the negative pressure between about 80 and 120 mmHg.

31. The method of claim 23, wherein sustaining comprises sustaining for more than 12 hours.

32. The method of claim 23, further comprising blocking outflow out of the expandable, non-permeable container.

33. A system comprising a sealable wound covering and any of the self-powered surgical drain devices of claims 1-22.

34. A system comprising: a sealable wound covering including an output port; a self-powered surgical drain device including: an input port configured to be secured in fluid communication with the output port of the sealable wound covering; an expandable, non-permeable container coupled to the input port;an absorbent material within the expandable, non-permeable container, the absorbent material configured to expand when exposed to liquid from the input port and to exert an outward pressure to expand the expandable, non-permeable container resulting in a negative pressure at the input port; and a wicking distributor within the expandable, non-permeable container arranged to distribute liquid from the input port to the absorbent material.

Images