Patent Description:
This application claims benefit of the following <CIT>.

Chronic and acute wounds, including pressure ulcers, diabetic wounds, and bums, present significant challenges to the health care industry. Patient care providers are actively seeking methods, devices, and systems for treating such wounds at a lower cost and with greater efficacy.

Conventional treatments for chronic wounds frequently include negative pressure therapy and/or hyperbaric oxygen therapy.

Negative pressure therapy is the controlled application of sub-atmospheric pressure to a wound using a therapy unit, such as a vacuum or suction device, to expose the wound to negative pressure to help promote wound healing. The wound is typically covered to facilitate the application of negative pressure and suction at the wound area. Various types of resilient, open cell foam surface dressings are typically sealed within an adhesive drape to provide the sub-atmospheric pressure at the wound site. Exudates are drained from the wound site and typically directed to a canister that stores the fluids and/or infectious material until properly disposed. Negative pressure wound therapy is often prescribed for chronic and acute wound types such as diabetic wounds, pressure ulcers, abdominal wounds, trauma wounds, various bums, flaps and grafts. However, negative pressure therapy may be less effective on patients having vascular disorders, such as diabetes, because negative pressure therapy can create a hypoxic environment at the wound. In current hospital settings, portable vacuum pumps are often rented or purchased for the purpose of providing negative pressure therapy. This can significantly increase the cumulative costs of providing wound care.

Hyperbaric oxygen therapy is the controlled application of oxygen to a wound at greater-than-atmospheric pressure(s). Oxygen is typically required for all new cell growth. Chronic or non-healing wounds tend to exhibit low oxygen tensions, or tend to be ischemic. A wound can become dormant if the amount of poorly oxygenated wound tissue reaches a critical mass. In this state, the body may no longer recognize the need to heal the affected area, thereby exacerbating the lack of oxygen in the wound and impairing healing of the wound by the body. Oxygen therapy is particularly useful for patients with poor circulation. The oxygen helps to kill bacteria and when applied to an open wound at a hyperbaric level, the oxygen is dissolved into the wound and absorbed by the surface wound tissue. The cells of the wound tissue that absorb the oxygen will begin metabolic activity in response to the increased oxygen tension. When the oxygen source is removed, the previously active cells request more oxygen from the body. The body responds by beginning to form new blood cells, and thus, starting the healing process. Accordingly, when delivered to a wound site under hyperbaric conditions, oxygen may act as a primary wound treatment fluid.

More recently, wound care systems and methods have been developed that combine negative and positive pressure (e.g. hyperbaric oxygen) wound treatment therapies. Such methods and systems are described, for example, in <CIT>; <CIT>; <CIT>; and <CIT>. Documents <CIT>, <CIT>, <CIT> and <CIT> disclose different wound drains.

Nevertheless, there is a need for wound drains that are particularly suited for negative pressure therapy or combined negative and positive pressure therapy. More particularly, there is a need for wound drains that have a structure that prevents collapse under negative pressure and avoids ingesting of foreign materials during therapy. The present disclosure addresses these needs.

The wound drain of the present disclosure advantageously incorporates structural components that prevent the drain from collapsing under negative pressure and from ingesting foreign materials introduced into the wound cavity, such as gauze and sponges, which can obstruct exudate flow through the drain. The wound drains are used in a conventional manner, being placed over wound sites and secured by an occlusive dressing hermetically sealing the wound site. The wound drains can be employed, for example, whenever a controlled distribution and/or collection of fluid(s) is desired. The wound drains facilitate negative pressure wound treatment, but may in other embodiments be adapted for use with combined negative and positive pressure (atmospheric or above) wound treatment.

Referring now to the drawings, <FIG> illustrate an embodiment of the wound drain, which is designated generally as reference numeral <NUM>. Wound drain <NUM> is configured to have a central semi-spherical dome <NUM> integrally rising from a flat annular flange <NUM> extending radially from the dome. Dome <NUM> has a dome wall <NUM> defining an interior dome chamber <NUM> with an open bottom. Flange <NUM> transitions radially outward from dome wall <NUM> at the bottom of dome <NUM>. Dome <NUM> also has an integral annular lip <NUM> that extends inward from dome wall <NUM> at the bottom of dome chamber <NUM> near the transition to flange <NUM>. Dome <NUM> may also has a plurality of radial support ribs (not shown) extending into dome chamber <NUM>.

Dome <NUM> also has a port connection <NUM> integrally formed therewith. Port connection <NUM> defines a fluid passage <NUM> in open communication with the dome chamber <NUM>. Port connection <NUM> is configured to receive one or more fluid lines or lumens (not shown). The lumens are operatively connected to the negative pressure supply and/or drain line so that the negative pressure draws exudate into fluid passage <NUM> through dome interior <NUM>.

Wound drain <NUM> is formed, molded or otherwise made of a pliable material, suitable for surgical and medical use. The pliable material may be a material suitable for medical purposes, such as a silicon rubber or Arkema Pebax® polymer. The pliable construction allows the drain to conform and contort so that the flange lies flat against the patient's skin, even over, around and into body creases and folds.

Wound drain <NUM> also includes a structural support or screen <NUM>. As shown, screen <NUM> is configured as a flat circular disc having a plurality of concentric arcuate openings or slits <NUM> formed in a segmented quadrant pattern. In other embodiments, the openings or slits in the screen may take other shapes and configurations. Slits <NUM> allow exudate and other fluids to pass from the wound cavity into dome chamber <NUM>, while preventing gauze and sponges from being ingested into the dome. The openings or slits are configured and dimensioned to provide sufficient area to allow fluid flow across the bottom of dome <NUM>, but are small enough to prevent foreign materials from migrating into and clogging fluid passage <NUM> of port connection <NUM>.

Screen <NUM> is restrictively seated at the bottom of dome <NUM> between an annular lip <NUM> and dome wall <NUM>. The conjunction between lip <NUM> and dome wall <NUM> creates a screen seat <NUM> which holds screen <NUM> at the bottom of dome chamber <NUM> in a "press-fit" type connection. In certain embodiments, suitable adhesives may be added at screen seat <NUM> to further join and secure screen <NUM> within dome <NUM>. Screen <NUM> is typically formed, molded or otherwise made of a pliable material, suitable for surgical and medical use, but also more rigid than the material of dome <NUM> and flange <NUM>. The screen material is selected so that screen <NUM> when seated within dome <NUM> provides sufficient structural integrity to hold the dome wall upright and prevent dome wall <NUM> from deforming and collapsing under negative pressure. The dome shape has a generous radius to allow for more pliability and reduced pressure points on the wound.

<FIG> and <FIG> illustrate two alternative embodiments of the wound drain, identified respectively as reference numerals <NUM> and <NUM>. Each wound drain <NUM> and <NUM> is identical in configuration and composition of drain <NUM> above, except that they employ a different structural component for preventing the drain from collapsing under negative pressure and from ingesting foreign materials introduced into the wound cavity, such as gauze and sponges, both of which can obstruct exudate flow through the drain. Wound drain <NUM> includes a dome <NUM>, port connection <NUM> and a flat screen <NUM> that is affixed to the bottom of flange <NUM> covering substantially the entire surface area of drain <NUM>. As with screen <NUM> above, screen <NUM> is typically formed, molded or otherwise made of a pliable material, suitable for surgical and medical use. More importantly, screen <NUM> is made of a material that is more rigid than the material of the dome and flange of drain <NUM>. Screen <NUM> is affixed to the bottom surface of flange <NUM> by adhesive layer <NUM>. Turning to <FIG>, wound drain <NUM> includes a porous insert <NUM> restrictively seated within the dome chamber. Insert <NUM> is composed of a fibrous or open-celled matrix of suitable materials that allows fluid flow therethrough, but lends internal structural support to the dome wall. Insert <NUM> is configured to restrictively seat within the dome chamber in a "press-fit" type connection similar to that of drain <NUM>.

<FIG> depicts a side view of another embodiment of the wound drain of the present disclosure. Wound drain <NUM> has semi-spherical dome <NUM> integrally rising from flat annular flange <NUM> extending radially from the dome. Dome <NUM> has a dome wall <NUM> defining an interior dome chamber <NUM> with an open bottom. The dome further includes port connection <NUM> in fluid communication with dome interior <NUM>. The dome <NUM> is shaped to have annular lip <NUM>. Annular lip <NUM> holds a support structure, which in this embodiment is a grate <NUM>. Grate <NUM> comprises a plurality of apertures providing fluid communication between the dome chamber <NUM> and a wound (not depicted). Grate <NUM> in some embodiments has a thickness that extends into the dome chamber. Grate <NUM> also may comprise a slightly domed or arcuate shape <NUM>. <FIG> depicts a cross sectional side view of dome <NUM>. Grate <NUM> may be shaped such that an annular cavity <NUM> extends upward towards dome <NUM>. Wound drain <NUM> is formed, molded or otherwise made of a pliable material, suitable for surgical and medical use. The pliable material may be a material suitable for medical purposes, such as a silicon rubber or Arkema Pebax® polymer. The pliable construction allows the drain to conform and contort so that the flange lies flat against the patient's skin, even over, around and into body creases and folds. The support structure, such as grate <NUM>, is made of a material that is more rigid than the dome material. It should be noted that the dome shape has a generous radius to allow for more pliability and reduced pressure points on the wound.

Turning to <FIG>, an embodiment of a wound drain having a dual lumen is depicted. <FIG> depicts a perspective view of wound drain <NUM> having dome <NUM>, flange <NUM> and first and second lumens <NUM> and <NUM>, respectively, each in fluid communication with the dome interior <NUM>. The first lumen provides connection to a drain line or negative pressure source (not depicted), while the second lumen advantageously provides a vent and/or an injection port for the introduction of fluids or gases. <FIG> is another perspective view depicting the interior of the dome <NUM> so that dome wall <NUM> and grate <NUM> can be seen. <FIG> is perspective partial cross sectional view of dome <NUM> depicting the apertures <NUM> of grate <NUM>. <FIG> further shows dome interior chamber <NUM> and annular lip <NUM>.

Turning to <FIG>, a top perspective view of grate <NUM> depicts a plurality of apertures <NUM>, and comprises an arcuate shape <NUM>. The apertures <NUM> may be of any size or shape suitable for allowing sufficient flow of wound exudate while preventing material from entering the lumen or lumens of the drain and also for manufacturing convenience. In this particular embodiment, apertures <NUM> are generally circular and arranged in a plurality of rows. The number of apertures can range from about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM> or about <NUM> to about <NUM>. Sidewall <NUM> of the grate generally curves inwardly, such that the radius of the bottom of the grate <NUM> is larger than the radius towards the top <NUM>. <FIG> depicts a bottom perspective view of grate <NUM>. Grate <NUM> may have a generally hollow annular ring <NUM>.

<FIG> depict yet another embodiment of wound drain <NUM> having a dome <NUM> (depicted from inside the drain), flange <NUM> extending radially from the dome and curved portion <NUM> extending upwardly from the flange toward the dome <NUM>. In this embodiment, drain <NUM> comprises a support structure of a plurality of arcuate ribs <NUM> integrally formed with curved portion <NUM>. <FIG> depicts a perspective view from underneath the drain upward towards the dome. In this embodiment, dual lumens <NUM> and <NUM> are depicted.

Claim 1:
A wound drain (<NUM>, <NUM>, <NUM>, <NUM>) for a wound cavity, the drain comprising:
a dome (<NUM>, <NUM>, <NUM>, <NUM>) having a chamber wall defining an internal dome chamber (<NUM>,<NUM>) with an open bottom;
an integral peripheral flange (<NUM>,<NUM>,<NUM>,<NUM>) extending radially from the dome;
a port connection (<NUM>,<NUM>,<NUM>) extending from the dome having a passage therethrough in fluid communication with the dome chamber; and
a support structure (<NUM>,<NUM>,<NUM>,<NUM>) within the dome chamber, the support structure comprising a plurality of openings for preventing foreign objects within the wound cavity from migrating into the dome chamber while allowing fluid flow from the wound cavity through the dome chamber and passage,
wherein the dome and flange are composed of a pliable material and the support structure is composed of a pliable material that is more rigid than the material of the dome and flange.