Abstract:
A drape for maintaining a sterile field for a real-time guided medical procedure (such as with ultrasound guidance) may include a contact film base having an aperture therethrough. A shield may project outwardly from the base and may surround the aperture.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention generally relates to apparatus and methods for maintaining a sterile field when employing a percutaneous medical device. 
         [0002]    Certain medical procedures such as intra-articular joint injections, peripheral nerve blocks, vascular access, and soft tissue biopsies, often rely upon ultrasound imaging to determine the location of the percutaneous device within a patient&#39;s body. 
         [0003]    A sterile field must be maintained around an entry point of a percutaneous device. When utilizing ultrasound for guidance for percutaneous procedures, the ultrasound probe is usually placed as close as possible to the sterile entry point so as to assure clear, real-time guidance through all tissues transected by the device. This sterile field must remain intact whenever ultrasound is used in the vicinity of the entry point. Consequently, guidance devices such as ultrasound probes used in such applications must be provided with sterile covering. Additionally, materials used to enhance the operation of the guidance devices also must be sterile. For example, gel material used in conjunction with a sterile ultrasound probe must also be sterile because the gel may migrate to the entry point of the percutaneous device during a procedure. 
         [0004]    As can be seen, there is a need for maintaining a sterile field for guided employment of a percutaneous medical device without incurring a need to employ sterile guidance devices. 
       SUMMARY OF THE INVENTION 
       [0005]    In one aspect of the present invention, a drape for maintaining a sterile field may comprise: a contact film base having an aperture therethrough; a coupler, and a shield projecting outwardly from the base and surrounding the aperture. 
         [0006]    In another aspect of the present invention, a method for performing a medical procedure may comprise the steps of: applying a sterile drape on a patient&#39;s skin with an aperture of the drape overlying a desired entry point; placing a medical device into an outwardly projecting shield of the drape; and performing the procedure while maintaining the medical device in the shield. 
         [0007]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of an operational aspect of a sterile-field drape in accordance with an embodiment of the invention; 
           [0009]      FIG. 2  is a perspective view of the sterile-field drape of  FIG. 1 ; 
           [0010]      FIG. 3  is an elevation view of the sterile-field drape of  FIG. 2 ; 
           [0011]      FIG. 4  is a cross-sectional view of the sterile-field drape of  FIG. 1 ; 
           [0012]      FIG. 5  is a cross-sectional view of the operational aspect of  FIG. 1  taken along the lines  5 - 5 ; and 
           [0013]      FIG. 6  is a flow chart of a method for performing a medical procedure in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. 
         [0015]    The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
         [0016]    Various inventive features are described below that can each be used independently of one another or in combination with other features. 
         [0017]    Broadly, embodiments of the present invention generally provide a sterile-field drape that may be positioned on a patient so that a percutaneous medical device may be operated through an outwardly projecting shield. 
         [0018]    Referring to the Figures, it may be seen that an exemplary sterile-field drape  10  may comprise a shield  14 , a coupler  26 , and an attachment contact film base  18 . 
         [0019]    The contact film base  18  may be provided with a layer  22  of adhesive and an adhesive protector  32 . The contact film base  18  may be polyurethane film or aromatic polyether polyurethane film. The material of the contact film base  18  may provide durable, intimate contact with the skin and allow unimpeded transmission of the ultrasound beam. The contact film base  18  may be pliable so that it can adhere to irregular skin surfaces. Finally, the contact film base  18  may be impermeable to liquids because it needs to assure a sterile barrier from the surrounding ultrasound gel. 
         [0020]    The shield  14  may be constructed from a thin, pliable film material such as polyester film or injection molded silicone. The shield  14  may be frustro-conical in shape to accommodate a wide variety of percutaneous devices. In other words, an upper extremity  14 - 1  of the shield may have an opening larger than an opening in a lower extremity  14 - 2  of the shield  14 . The shield&#39;s size may vary based upon the location and application. For example, for a procedure on a finger this could be about 4 to 6 cm. For a procedure on an abdomen, the outer width could be 8 to 12 cm. The shape may enable the guidance device  12  (such as the ultrasound probe) to be placed as close as possible to the sterile target area but may allow for ease of manipulation of the percutaneous medical device with minimal hindrance while maintaining good visualization at all times. The shield  14  may project out from an aperture  18 - 1  at adjustable angles high enough to maintain a sterile field around the target area (i.e. always prevents non-sterile ultrasound-probe gel from spilling into the sterile target area). The shield  14  may also be constructed with an embedded light spring (plastic or metal) in the same frustro-conical shape. This would allow the entire sterile-field drape  10  to be packaged in a collapsed form. 
         [0021]    A coupler  26  may hold the shield  14  in position on the contact film base  18 . The coupler  26  may be constructed of liquid silicone injection molding or polyurethane that is either press fit or glued. Alternatively, all components may be one solid molded material to conjoin the shield  14  and the contact film base  18 . The coupler  26  may be of appropriate durometer to enable the clinician to manipulate the percutaneous device within the shield  14  through a wide range of angles without compromising the integrity of the sterile field drape  10  at the point where the shield  14  narrows to the aperture  18 - 1  on the target site. The shield  14  and the coupler  26  may surround the aperture  18 - 1  in the contact film base  18 . The aperture  18 - 1  may be any size large enough to accommodate a percutaneous device  16  but small enough for the shield  14  to maintain the sterile barrier. Smaller apertures would be preferred as the optimal procedure would be one where the ultrasound probe is placed close to the entry point of the percutaneous medical device  16 . This would assure continuous visualization of the percutaneous medical device through all tissues transected. For typical applications, this aperture  18 - 1  may be about 5 to 10 mm in diameter. 
         [0022]    In operation, the sterile field drape  10  may be placed on a patient  34  so that the contact film base  18  is adhesively attached to a sterilized portion of a patient&#39;s skin  28 . The contact film base  18  may be positioned so that the aperture  18 - 1  overlies a desired entry point for the percutaneous medical device  16 . A practitioner  36  may place the percutaneous medical device  16  within the shield  14  and insert the device  16  into the entry point. A guidance device  12  such as an ultrasound probe may be placed on the contact film base  18  which overlies the patient&#39;s skin  28  in close proximity to the entry point so that the practitioner  36  may more readily guide the device  16  to a desired target area  30 . 
         [0023]    The shield  14  of the sterile field drape  10  may preclude contact between the guidance device  12 , such as the ultrasound probe, and the percutaneous medical device  16 . Thus, there may be no need to maintain the guidance device  12  in a sterile state. Moreover, if the guidance device  12  needs a gel application  20  for proper operation, the practitioner  36  may employ non-sterile gel because the shield  14  may also preclude contact between the gel  20  and the percutaneous medical device  16 . 
         [0024]    It may also be noted that, because the shield  14  may be pliable, the percutaneous medical device  16  may be readily manipulated by the practitioner  36  while the shield  14  may be displaced in conformity with the position of the percutaneous medical device  16 . 
         [0025]    While the sterile-field drape  10  has been described herein as being particularly useful in procedures using of a first medical instrument (e.g., the percutaneous device  16 ) inside the shield  14  and a second instrument (e.g., the probe  20 ) outside the shield  14 , it should be noted that the sterile-field drape  10  may be useful for any application in which it is desired to expediently produce and maintain a sterile field of limited size. 
         [0026]    It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.