Surgery – Container for blood or body treating material – or means used... – Filter or series thereof for liquid entering or leaving...
Reexamination Certificate
1998-12-04
2001-08-28
Sykes, Angela D. (Department: 3762)
Surgery
Container for blood or body treating material, or means used...
Filter or series thereof for liquid entering or leaving...
C604S006150, C604S004010, C604S327000, C422S044000, C210S323100, C210S346000, C210S455000, C210S445000
Reexamination Certificate
active
06280429
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved filter, and more particularly to a gross filter for use in a drainage device. Specifically, the present invention relates to a gross filter with an open face that is configured to lessen filter blockage by gross particulate matter, for example blood clots, entrained in incoming fluid while also permitting a clear view of blood clot volume retained inside the filter.
2. Prior Art
Gross filters for use in filtering out large particulate matter entrained in body fluids drained from a patient during convalescence or post-operative recovery are well known in the art. Typically, gross filters of this kind are incorporated in a drainage device, for example a Chest Drainage Unit (CDU), for filtering blood clots and other gross contaminates from body fluids before reinfusing such fluids back to the patient.
A CDU is an apparatus for suctioning gases and liquids from the pleural cavity of a patient in order to re-expand the patient's lungs. The pleural cavity lies within the rib cage above the diaphragm and is surrounded by the pleural membrane. The pleural cavity contains both lungs, which in their normal expanded state fill the pleural cavity. Several conditions and diseases such as interventional surgery, trauma, emphysema and various infections can cause a build up of liquid and gases around the lungs in the intrapleural space. When this happens, it causes the lungs to collapse to a volume much less than that of the pleural cavity, thereby severely impairing breathing functions of the patient. The lungs can be re-expanded to their normal state to fill the pleural cavity by draining the liquid and gases from the intrapleural space using the CDU. A typical CDU and its operation is disclosed in U.S. patent application Ser. No. 08/810,056 to Swisher et al. entitled “Chest Drainage Unit with Controlled Automatic Excess Negativity Relief Feature”, assigned to the assignee, and is herein incorporated by reference in its entirety.
During the draining of fluid from a patient's pleural cavity blood clots may develop and become entrained in the fluid as it enters the collection chamber of the CDU for eventual reinfusion to the patient. During reinfusion of blood, it is desirable that the collected blood be free of any large particulate matter or other kinds of gross contaminants before entering and collecting at the bottom portion of the collection chamber. In order to screen out these undesirable contaminants a gross filter is provided near the inlet to the collection chamber for filtering out large particulate matter as fluid enters the CDU. The Swisher et al. device referenced above is generally exemplary of medical drainage devices that incorporate a gross filter for filtering out blood clots and other large particulate matter from fluid drained from a patient's pleural cavity. The gross filter used in the Swisher et al. device comprises a porous filtering material placed near the inlet of the collection chamber in a horizontal orientation so that all incoming fluid must pass through the gross filter before collecting in a pooling area located at the bottom portion of the collection chamber. In this manner, incoming fluid is filtered prior to entering the pooling area so that blood clots and other large particulate matter are retained on top of the filter.
Unfortunately, the gross filter of the Swisher et al. device suffers from several drawbacks. First, blood clots that are filtered out and retained inside the gross filter will begin to block and impede the flow of fluid being filtered as blood clots begin to accumulate and spread over the surface area of the filter, thereby wasting blood that could be reinfused back to the patient. Second, the gross filter of the Swisher et al. device is made from a reticulated foam material which has a tendency to separate into smaller fragments when trimmed for the size required to properly fit into the collection chamber, thus causing possible contamination of already filtered fluid by these separated fragments.
As of yet, nothing in the prior art has addressed the problem of developing an improved gross filter made of a solid unitary construction that advantageously prevents total blockage of the filter by gross contaminants while also addressing the need for a gross filter that permits clear viewing and accurate visual measurement by medical personnel of the volume level of gross contaminants retained in the filter.
OBJECTS AND SUMMARY OF THE INVENTION
The principal object of the present invention is to provide a gross filter having a configuration that inhibits or prevents the total blockage of the filter by large particulate matter and other contaminants.
Another object of the present invention is to provide a gross filter that filters out large particulate matter, for example blood clots, before collection in the collection chamber.
A further object of the present invention is to provide a gross filter that permits clear visual measurement by medical personnel of the amount of large particulate matter and other gross contaminants retained inside the filter.
Another principal object of the present invention is to provide a means for channeling incoming fluid through a portion of the gross filter in order to prevent total blockage of the gross filter.
These and other objects of the present invention are realized in the preferred embodiment of the present invention, described by way of example and not by way of limitation. The preferred embodiment provides for a gross filter comprising a bottom panel, two side panels, and a back panel that collectively form a filter body having a generally rectangular cross-section. The filter body is configured so as to have open top and front portions, angled back and side panels, and a slanted bottom panel that forms an angled slope towards one end of the gross filter. Alternatively, the gross filter may have other shapes that include, but are not limited to, semicircular/conical or diamond shaped, with open front and top portions, which are suitable for filtering gross contaminants from incoming fluid.
The angled back and side panels of the filter body are configured so as to prevent total blockage of the filter body by channeling blood clots to one end thereof. The back and side panels are configured such that gravity will force blood clots to one portion of the gross filter due to their set angle. This type of angled configuration ensures a sufficient filtration rate through the gross filter when the bottom panel is partially or totally blocked with large particulate matter and promotes a maximum filtration rate when there is no blockage of the filter body present. A guide is provided on the interior portion of the gross filter's back panel for channeling incoming fluid toward one portion of the gross filter in order further prevent total blockage. A gutter ledge is provided along the top portion of the back panel for channeling incoming fluid towards one portion of the filter body that contacts the top portion of the back panel between the guide and the side panel under the inlet port.
The open front portion of the gross filter is positioned adjacent a partially transparent front wall of the CDU and allows for unobstructed viewing of the interior portion of the gross filter when large particulate matter entrained in incoming fluid are screened out and retained therein. Where large particulate matter has blocked the back, side and back panels of the gross filter, an overflow panel is provided for filtering fluid that overflows the interior portion of the gross filter or when the overflow of the entire first subchamber occurs.
The gross filter of the present invention is adapted for placement adjacent or near the inlet port inside a collection chamber of a drainage device, such as a CDU, for filtering incoming fluid of large particulate matter and other gross contaminates entrained therein. Preferably, the CDU is of the type that includes a collection chamber that comprises two or more subcham
Lewis Anthony K.
Swisher David Rork
Weilbacher Eugene E.
Yam Jacky S.
Bianco Patricia
Brown Rudnick Freed & Gesmer
Leonardo Mark S.
Sherwood Services AG
Sorell Peter B.
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