BACKGROUND OF THE INVENTION Field of the Invention This invention relates to the protection of health care personnel from potentially contaminated fluids. In particular, it relates to a shield and method of using a shield for containing spent irrigation fluids or wound drainage fluids. Related Developments

Heretofore, body fluids resulting from procedures such as wound irrigation and abscess-drainage frequently splashed or squirted back onto the physician or health care personnel performing the procedure. This is highly undesirable, especially if the irrigation fluid or wound abscess fluid are contaminated by Human Immunodeficiency Virus, hepatitis Type B or C viruses, or other pathogens capable of transmitting disease by contact with mucous membranes or openings in the skin. Thus, these fluids present infectious hazards to health care personnel and can also soil clothing. The common practice has been to use several gauze pads to partially block the spray of body fluids, such as blood or purulent material, while allowing a compromised view of the task at hand. While offering some protection to the operator, the degree of protection is unfortunately inversely proportional to the operator's ability to see the wound site. Other methods to cope with this problem have included protective face shields, goggles or stationary plastic sheeting erected between the operator and his patient. The various goggles and face shields have ceased to gain wide acceptance and use due to discomfort, cost, and a need for cleaning between use. Goggles and face shields also do nothing to protect the clothing of both the operator and the patient. The plastic sheet barriers also require cleaning or a change of the sheet, lack mobility, and do not prevent the splash of body fluids onto the patient, linens, and

forearms of the operator. The "Simpulse Pulsed Lavage System" marketed by Davol Inc. is a self-contained, high volume, high velocity wound irrigation system designed to prevent contamination of the patient and health care personnel in the irrigation fluid. However, this system is limited to use in the operating room due to its size, cost, and the production of one or more liters of blood- tinged saline.

U.S. Patent No. 4,769,003 shows a splash shield for preventing backsplash of irrigation fluid. In this device, a syringe body is affixed to a central irrigation port that is spaced a substantial distance from the wound site. In addition, this shield is quite rigid and cannot be pierced by medical instruments, such as hypodermic syringes or scalpels, and cannot be easily conformed by hand applied force to the shape of the wound site.

U.S. Patent No. 3,367,332 and U.S. Patent No. 4,911,688 show sealing devices placed over a wound to enhance cleansing, healing or disinfection with irrigation fluids. These arrangements show insertion of hypodermic needles into membranes communicating or forming fluid filled chambers. However, these designs do not show hand¬ held shields for preventing backsplash.

German Printed Patent Publication No. 28 09 828 also illustrates a protective cover for irrigating wounds, which cover is adhesively fixed to a body.

British Patent No. 641,061 shows an irrigation system with a wound cover strapped in place over the wound. U.S. Patent No. 4,798,599 shows an eye cup with an irrigation fluid supply and collection system.

SUMMARY OF THE INVENTION It is an object of the invention to provide a low cost, hand-held device and method of using the device for protecting health care workers from the spray or splash of irrigation or body fluids.

It is another object of the invention to provide a low cost shield through which wound treatment procedures can take place by piercing the wall of the shield to allow optimum positioning of medical instruments; it is a further object of the invention to provide a hand-held shield capable of being conformed to the wound site; it is a further object of the invention to provide a single use, low cost, sterile device and method for its use for maximizing the protection of health care personnel from infectious disease while performing medical procedures.

Briefly, these and other objects of the invention are achieved by the use of a transparent dome-shaped shield that can be placed near or over the wound site to contain splashing or squirting of irrigation or wound fluids. The wall of the shield has sufficient rigidity to maintain the dome-shape of the shield but is pierceable by medical instruments for performing medical procedures at a wound site covered by the shield. The shield can be manually conformed to the shape of the wound site to maximize splash protection. The shield can be provided as a sterile, single use product.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a top view of a shield embodying the invention; Figure 2 is a cross-section of the shield taken along line II-II of Figure 1 ;

Figure 3A shows the shield of Figure 1 placed on a patient's skin and conforming to the general contour of the body part; Figure 3B shows the shield as positioned in Figure

3A pierced by a needled irrigating hypodermic syringe and enclosing backsplash produced by wound irrigation;

Figure 3C shows the shield of Figure 1 pierced with a needled irrigating syringe but held out of contact with the wound margins and providing a shield from contaminated backsplash;

Figure 3D shows the shield of Figure 1 held slightly above a wound site while a needled irrigation syringe is passed under the shield, with the shield providing protection against backsplash. Figure 4 shows the shield of Figure 1 being pierced with a scalpel during incision and drainage of an abscess, thereby preventing expulsion of purulent material onto health care personnel; and

Figure 5 is a cross-section view of the shield shown in Figure 1 contained in a sterility barrier package.

DESCRIPTION OF PREFERRED EMBODIMENTS This invention relates to a pliable, clear, pierceable, hand-held dome-shape shield and to methods of using such a shield to contain backsplash of contaminated fluids during medical procedures.

A suitable shield embodying features of the invention is shown in Figures 1 and 2. The shield 1 comprises a dome-shaped body 2a having a small, out-turned flange or rim 2b. The shield 1 is formed of a substan¬ tially transparent plastic sheet material that is suffi¬ ciently rigid to form a stable, self sustaining dome- shape, yet is capable of being pierced by sharp medical instruments, such as hypodermic needles and scalpels. The body 2a of the shield 1 can be formed in substantially any dome-shaped configuration, with a preferred shape being that of a truncated hemisphere, as shown in Figure 2. The body 2a is of a size to be readily hand-held and manipulable. The radius r can be from about 1.5 to about 3 inches. A shield in the form of a truncated hemisphere having a radius r of about 1.75 inches and a height h of about 1.3 inches has been found to be particularly useful in the present invention.

Preferably, the shield body 2a and flange 2b are integrally formed from a clear or transparent synthetic polymeric material, so that the wound site can be seen through the shield body 1. The material forming the

shield provides a relatively rigid body 2a capable of maintaining the dome-shape, yet being sufficiently thin to allow the shield 1 to be pierced by medical instruments, such as hypodermic syringes and scalpels. One material that has been found particularly useful for this purpose is a thermoplastic plastic polyester sold under the tradename PETG by Eastman Kodak Corporation. Such sheet material having a thickness t of about 0.012 to about 0.02 inches has been found particularly useful for this purpose. Such a material can be shaped by conventional methods, such as thermoforming, to form the shield 1. It is desirable to form the shield 1 of materials that can be subjected to industrial sterilization processes, such as gaseous ethylene oxide or irradiation processes. If radiation sterilization is contemplated, the material forming the shield 1 should be radiation stable. Also, other transparent rigid, thermoplastic films made from materials such as polyvinyl chloride, can be used to form the shield 1. The rim 2b is provided for comfortable contact with the skin of the patient and to provide resistance to collapse of the body 2a upon application of inwardly directed forces applied to opposed sides of the body 2a. An aspect of the flange width d is that it be sufficient to provide some peripheral stabilization of the shape of the shield yet not interfere with the ability to conform the shield to the wound site by application of opposed, laterally directed forces hand applied to the dome-shaped body 2a. Consequently, the rim 2b is relatively narrow. For example, with a hemispherical shaped shield having the dimensions discussed above, a flange width of approxi¬ mately 0.06 inches is useful. Because the shield is used as a temporary barrier, the lower surface of the rim 2b can be free of adhesives for adhering the shield 1 to the skin of the patient.

One method of use of shield 1 as shown in Figure 3A involves the following steps. An absorbent cloth or

disposable pad 3 is placed under the body part with the wound 5 to be irrigated. The sterile plastic shield 1 is taken from the sterile instrument tray with the fingers gripping either side near the outer edges. The shield 1 is placed over the wound 5 with the rim 2b against the skin 6. The operator then conforms the flexible clear plastic shield 1 by squeezing the sides with one hand 7 as necessary to get the best seal with the underlying skin forming the wound margins, as shown in Figure 3A. A needled hypodermic syringe 4 containing sterile saline or other irrigating fluid is manipulated with the operator's other hand 8 to pierce the dome-shaped body 2a of the shield at 9 over the underlying wound 5, as shown in Figure 3B. Alternately, the shield 1 may be pierced by the syringe before the shield is placed on the patient. Irrigation of the wound with a stream of fluid 10 is accomplished in the traditional fashion by applying pressure to the syringe plunger 11 , forcing a stream of fluid 10 from the needle into the wound 5, thereby dislodging foreign materials and blood clots and cleansing the tissues of microbial, chemical or other contaminants. Adherent foreign material in the wound 5 may be dislodged by the needle tip. The transparent plastic shield 1 allows direct visualization of the procedure while preventing the backsplash 12 of blood-tinged fluid onto the operator or surrounding linens. Of special concern is the prevention of this spray from contacting the mucous membranes of the operator's eyes, nose and mouth, which could cause transmission of various diseases such as Human Immunodeficiency Virus or serum hepatitis (Type B or C) . The effluent irrigation fluid is allowed to coalesce and form droplets 13 that flow down onto the absorbent pad 3 placed earlier beneath the patient. The absorbent pad 3 is discarded at the end of the procedure, according to prevailing medical practice. If the wound dimensions are larger than the shield, irrigation is accomplished by serial placement of the shield 1 until the wound is entirely cleansed.

Some areas of the body may not allow desired conformation of the shield to the skin surface, as depicted in Figure 3C. In this situation the shield 1 still provides substantial protection to the health care worker by creating a splash-free zone 14 substantially in the shape of a solid sector of a sphere. This procedure is the same as outlined for Figure 3B except no attempt is made to conform the plastic shield to the skin surface. The shield 1 is pierced by the irrigating needle 9 but remains above the surface of the skin. It is held in position on the shaft of the needle by either friction with the plastic or with one of the operator's hands. When irrigation fluid 10 is forced into the wound, back¬ splash 12 is produced but blocked in its path toward the operator by the clear plastic shield 1 , providing substan¬ tial protection while allowing direct line of sight for the operator. Since the degree of backsplash reduction is inversely proportional to the distance between the dome and the wound being irrigated, it is desirable to keep the dome 1 and syringe 4 as close to the wound 5 as possible. At the end of the procedure, all single use items and the absorbent pad(s) 3 are disposed of in the locally prescribed fashion.

Alternatively, the shield 1 can also be used as shown in Figure 3D, without piercing by a medical instru¬ ment. The shield is held by the non-dominant hand 7 of the user near the wound site, a sufficient distance, usually 1 to 2 inches, to allow an instrument, such as an irrigation syringe 4, to be manipulated adjacent the wound. The shield 1 is positioned to prevent backsplash toward the user and provides a zone of splash protection 14 in the form of a sector of a sphere, as in the method of use described with respect to Figure 3C. Fluid droplets coalesce within the interior of the shield and fall, as larger drops, onto an absorbent cloth 3 placed adjacent or under the part of the body where the wound is situated. As with previously described methods of use.

the wound site can be visualized through the shield while the wound treatment is taking place.

Other methods of use for this type of device include the incision and drainage of body fluid cavities which may be under pressure. In Figure 4 the procedure is much the same as outlined for wound irrigation in Figure 3A including placement of absorbent pad(s) 3 under the affected body part 15. Instead of using a hypodermic syringe and needle, a scalpel 16 or other penetrating device is used to pierce the plastic shield 1 which has been placed over an abscess, hematoma or other subcutaneous fluid cavity 18 potentially under pressure. The fluid cavity 18 may be incised with an incision 19 and drained below the protective barrier provided by the shield. Once the fluid 20 under pressure is initially released, the shield may be removed and properly discarded. This method of use protects the operator from expelled purulent or other body fluids 20, which could potentially transmit disease. ^' Alternatively, the shield 1 may be held a short distance from the incision site, similar to the manner as described with respect to Figure

3D. The shield is held by the user in a position to intercept splashing or squirting fluid from the incision.

Preferably, the shield 1 is provided in a sterile, single use, disposable form. Referring to Figure 5, the dome 1 is contained within a sterility barrier package formed by the lower sheet 20 and the upper sheet 22 that are joined together by suitable means, such as a peripheral heat seal 24. The sheets 20 and 22 are formed of medical packaging materials that form a microbe impervious barrier so that, once the packaged shield 1 is sterilized, it is maintained in sterile condition within the enclosure formed by the films 20 and 22. Suitable packaging materials are known to those in the medical device art and the choice of such materials depends largely on the type of sterilization system used, either gas or irradiation. Ideally, the films 20 and 22 are joined in a manner such that they can be readily peeled

apart to allow sterile delivery of the shield 1 to the operating field.

As can be seen from the foregoing discussion, a device and method are disclosed that provide significant advantages. A sealed enclosure having high fluid integrity can be provided at a low cost. The wound site is highly visible and the pierceable shield allows optimal placement of medical instruments with respect to the wound. The shield is useful for both irrigation purposes and for performing fluid drainage operations. The shield may be used alternatively in a pierced or non-pierced mode, depending on the physicians preference or the exigencies of the procedure. The use of the shield encourages aggressive irrigation, thereby promoting thorough wound cleaning and reducing wound infections.