This invention relates generally to apparatus and methods for draining body fluids. More particularly, it relates to apparatus and methods for reducing the likelihood of infection during the collection of fluids from body cavities of human and animal subjects by draining and disposing of the fluids without exposing the apparatus or the subjects to potential sources of contamination and infection. Background Art

In modern medical practice it is often necessary or desirable to catheterize patients for drainage of bladder, closed wound or other body cavities. In such situations, it is essential to prevent undesirable micro-organisms from gaining access to the catheterized cavity.

Unfortunately, conventional drainage devices are a prime source of infection in catheterized patients. For example, in the area of bladder drainage, a large proportion of catheterized patients suffer from urinary tract infections attributable to contaminated drainage devices. In many cases, the drainage collection device itself becomes contaminated in use and infection then ascends in a retrograde manner from the drainage collection device to the patient via the drainage catheter. Such retrograde infection from a contaminated drainage or infusion device has been observed, for example, in patients undergoing urinary, wound, biliary, or gastro-intestinal drainage, peritoneal

dialysis, and hyperalimentation treatment. See, e.g. E.M. Goldberg, et al., "Peritoneal Dialysis", Dialysis and Transplantation, June/July 1975, Vol. 4 #4; J.H. Isaccs, et al., "Foley Catheter Drainage Systems and Bladder Damage", Surgery, Gynecology & Obstetrics, May 1971, p.889; R.E. Desautels, "The Causes of Catheter-Induced Urinary Infections and Their ^" Prevention", J. Urology, 1969, 101:757; R.E. Desautels, et al. "Technical Advances in the Prevention of Urinary Tract Infection", J. Urology, 1962, 87:487; R.E. Desautels, "Aseptic Management of Catheter Drainage", New Eng. J. Med., I960, 263:189; E.H. Kass, et al., "Prevention of Infection of Urinary Tract in Presence of Indwelling Catheters", J.A.M.A. 1959, 169:1181; and E.H. Kass, et al. "Entry of Bacteria into the Urinary Tracts of Patients with Inlying Catheters" New Eng. J. Med., 1957, 256: 556.

Contamination of drainage collection devices often arises from reusing containers designed to be filled repeatedly with drained body fluid and emptied. For example, the evacuator described by McElhenny in U.S. Pat. No. 3,115,138 includes a capped fluid outlet. After the evacuator becomes filled it is emptied for reuse by removing the cap and expelling collected fluid via the outlet. During this operation the interior of the evacuator is exposed to the atmosphere and contamination of the evacuator may result.

Efforts have been made to reduce the contamination of drainage devices during periodic emptying. For example, U.S. Pat. Nos. 3,779,243 and 3,774,611 disclose evacuators which employ a special valve over the fluid outlet. This valve operates to close the outlet at all times except for the time when fluid is actually being purged

from the evacuator. Such evacuators may succeed in reducing the contamination brought on by purging. However, since these evacuators must be periodically opened for purging, they are exposed to the surrounding atmosphere and can become contaminated and therefore a source of infection. Goldberg and Bazell, in their U.S. Patent No. 4,435,171 for Apparatus to Be Worn And Method For Removing Fluid From A Living Subject, describe a closed, gravity drainage system designed to minimize retrograde introduction of microorganisms into a patient. This system, however, has no provision for suction drainage. Disclosure of Invention

The present invention is directed to a closed drainage apparatus for receiving fluid (liquids and gases) from body and tissue cavities including suctioning means in communication with the cavities for suctioning and receiving the drained body fluids. In an important embodiment, the suctioning means comprise a resilient bellows which draws body fluid from the cavities under the inherent spring back suction force produced as it returns to its normal, expanded condition.

The apparatus also includes a reservoir into which excess body liquids from the suctioning means are automatically siphoned and into which the suctioning means may be emptied, all without exposure of the system to the atmosphere. In an important embodiment of the invention, the secondary reservoir consists of an impervious, flexible bag in communication with an outlet port of the suctioning means which has a one-way valve at its inlet to prevent liquid from flowing back from the reservoir.

In yet another important embodiment of the invention, the secondary reservoir is vented to the atmosphere through one or more small pore hydrophobic filters to permit gases in the system to be purged without retrograde introduction of microorganisms into the reservoir.

It is therefore an object of the present invention to provide an improved apparatus and method for draining body fluids from a body cavity under suction in which potential retrograde infection due to contamination of drainage devices on exposure to the atmosphere is eliminated.

It is a further object of the present invention to provide an improved apparatus and method for collecting body fluids including liquids and gases from a body cavity under suction in which collected liquids are siphoned into disposable containers for disposal and collected gases are vented to the atmosphere without exposing the system to the atmosphere and without exposure of hospital personnel to the container contents.

Yet another object of the invention is to provide a closed drainage system in which gases in the system can be purged without exposing the system to the atmosphere.

A still further object of the present invention is to provide an economical, easy to use, closed suction drainage apparatus and method. These and other objects of the present invention will become apparent to those skilled in the art upon consideration of the accompanying specification, claims and drawings.

Brief Description of the Drawings

The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and advantages, may be best understood by reference to the following description, taken in conjunction with the following drawings, in which like reference numerals identify like elements in the several figures and in which:

FIGURE 1 is a perspective view of a closed drainage apparatus in accordance with the practice of the present invention; FIGURE 2 is a cross-sectional elevation view of the apparatus of FIG. 1, taken generally along section line 2-2 of that figure;

FIGURE 3 is an enlarged cross-sectional view of a one-way valve illustrated in FIG. 1, taken along section line 3-3 of FIG. 1;

FIGURE 4 is an enlarged cross-sectional view of that portion of the apparatus of FIG. 1 containing a vent hole and filter for purging air from the apparatus, taken along section line 4-4 of FIG. 1;

FIGURES 5 is a front elevation view of a film valve employed in the apparatus of FIG. 1; and

FIGURES 6A-6E are cross-sectional elevation views of the apparatus of FIG. 1, showing the operation of the apparatus of FIG. 1 in draining and storing body fluids. Modes for Carrying Out the Invention

Turning now to FIGURES 1 and 2, an apparatus for collecting body fluids 10 is illustrated including a resilient bellows 12 mounted to a support housing 14 by way of an externally threaded neck 16 which is screwed into an internally threaded integral flange 18 of the housing.

The bellows, which comprises the suctioning means of the invention, is preferably constructed of polyethylene, although it may be made of other impervious resilient materials such as polypropylene. In fact, the suctioning may be accomplished using any sort of reservoir capable of producing sufficient negative pressure, when evacuated, to draw blood, serum, pus, gases and other fluids from a wound site. In the illustrated embodiment, resilient bellows 12 has a liquid capacity in its normal extended state of about 150cc.

A conventional drain 20 of the type placed in body or tissue cavities of patients undergoing urinary, wound, biliary, gastro-intestinal drainage, peritoneal dialysis, and hyperalimentation treatment is connected to a suction port 22 of the apparatus by way of an appropriate length of flexible tubing 24 affixed at one end to the drain and at the other to the proximal end of the suction port. Suction port 22 passes through housing 14 and into the area circumscribed by flange 18. A one-way gross reflux valve 24 (FIG. 3) is affixed to the distal end of the suction port, positioned as near as practical to the top of bellows 12. Although it is preferred that a duckbill valve be used as the gross reflux valve, other conventional one-way valves may be used, such as ball, check and diaphragm valves. The primary consideration in the choice of the valve is that it prevent fluid reflux and that it not interfere with the bellows when the bellows is compressed during ^" operation of the apparatus.

In addition to suction port 22, a drainage port 26 passes through housing 14 and into the area circumscribed by flange 18 to communicate with the interior of bellows 12. The distal end of the drainage port

is connected to a tube 28 located within the housing which is routed into the top of a secondary reservoir 30. In the illustrated embodiment, secondary reservoir 30 is a clear, flexible polyethylene bag although other impervious containers (flexible or rigid) could be used. The size of the reservoir is a matter of choice, although in typical applications where a polyethylene bag is used, the reservoir will be large enough to the contain 500, 1000, or 2000cc of liquid. As illustrated in the figures, reservoir 30 has a 500cc capacity and is marked to indicate its level of fill. Reservoir 30 is attached and heat sealed to a flange 32 protruding downwardly from housing 14. A rigid tube 29 protrudes from the flange into the top of reservoir 30 where it terminates in a second anti-reflux valve 50.

Anti-reflux valve 50 must be chosen for maximum contact sealing area to prevent blood clots and other solids from causing leakage across the valve. While a conventional Heimlich valve could be used, a film valve 50 particularly useful in this application is illustrated in FIGURE 5. In addition to its excellent sealing properties (even in the presence of solids in the sealing area), the film valve is particularly well adapted to the present application since it does not create dead space in secondary reservoir 30.

The film valve is made up of two pieces of virtually any type of plastic film, such as polyethylene, mylar, nylon or PVC, as well as laminates of these materials. The only requirement in choosing the plastic films is that the combination of plastics do not adhere.

Also, it has been found to be preferable to use films with a combined

thickness in the- range of about 3-5 mils. The edges of the two film members of the valve are heat sealed to each other with a tortuous profile 51 at the closed edges of the valve in order to prevent fluid leakage. Housing 14 includes a vent 34 (FIG. 4) in communication with reservoir 30. Vent 34 permits air from the secondary reservoir to escape as it is filled with liquid during the drainage procedure. The vent also permits gases which may be drawn into the system from the drain site by way of drain 20 to escape. Absent vent 34, reservoir 30 would not be able to be filled to capacity with liquid due to space taken up by gases in the system. Also, by eliminating gases from the system through vent 34, the reservoir may be maintained in a lower and easier to handle profile.

A small pore hydrophobic filter 36 is heat sealed into vent cup 34 which is friction fit onto a flange 40 encircling port 34. Filter 36 prevents the migration of bacteria into the system. It also makes it possible to vent gases without impairing the "closed" nature of the system. The vent cap is positioned at the top of the housing in order to prevent the filter from getting wet, which could cause clogging. Although only a single vent cup and filter are illustrated in order to simplify the figures, two or more cups and filters could be used.

Hydrophobic filter 36 must have a pore size less than or equal to 0.45 microns in order to prevent bacterial migration. One useful filter material is an expanded PTFE membrane available from W.L. Gore & Associates, Inc. of Elkton, Maryland under the name "GORE-TEX EXPANDED PTFE". Alternative materials include woven fabric filters such as those available from PALL Bio-Medical Products Corporation of Glencove, New York under the trademark "PALLFLEX".

The operation of the apparatus of the present invention is illustrated in FIGURES 6A-E. It is to be understood in this discussion of the operation of the apparatus of the invention that the apparatus is affixed to the patient's bed or clothing by way of hook 42 (FIG. 1) or other fastening devices at a position below the wound site.

Looking first to FIG. 6A, the apparatus is shown in an empty condition, with bellows 12 extended. In FIG. 6B the bellows are manually compressed, forcing the air in the bellows through tube 28, past valve 50 and out of the system through hydrophobic filter 34.

In FIG. 6C, the resilient bellows are permitted to expand. Since the system is sealed (film valve 50 is closed due to the suction created by the bellows), liquid and gases are drawn from the wound site through the suction port 22 past gross reflux valve 24 and into the bellows.

Once started, the bellows continue filling with liquid (FIG. 6D) until the liquid reaches the bellows top. At that point, due to the siphon effect produced by the positioning of the apparatus below the wound site, surplus liquid automatically enters tube 28 and flows into reservoir 30, as shown in FIG. 6E. The fluid entering the bag displaces any gases therein which exit the system through vent 34 and filter 36.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention and, therefore, it is intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.