Abstract:
This invention provides a female medical coupling port with an integrated port guide to enable more accurate and precise coupling of a male port coupling (such as the cannula of a syringe) and to prevent port exposure to non-sterile objects. The male and female ports can be arranged according to standard dimensions for male and female luer taper fittings recognized by ANSI and by ISO. This guide-shielded port is usable with the standard ANSI and ISO male cannula widely used in the medical field. In an embodiment the female port is used in medical fluid systems to receive a blunt male cannula, such as those found in the luer lock fitting of needle-less syringes and IV tubing systems to establish a mechanical coupling. Female ports allow coupling of devices (e.g. syringes and IV tubing) to a variety of medical applications including stopcocks, minimum fluid displacement medical couplings, female-to-female adapters, port dead-end caps, IV extension sets, pressure-monitoring devices, etc. The port guide can be constructed as a unitary part of the port, or can be a retrofittable structure that is either snapped into place on, for example, a female port stem, or slid onto a port, such as a minimum displacement fluid coupling. Appropriate drain ports can be provided in the port guide to prevent capture of excess fluid.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 60/010,749, filed Jan. 11, 2008, entitled MECHANICAL COUPLING PORT WITH GUIDE FOR REDUCTION OF CONTAMINATION, the entire disclosure of which is herein incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to medical luer lock fluid couplings or ports, and more particularly to male-female threaded fluid couplings constructed in accordance with ANSI standards. 
       BACKGROUND OF THE INVENTION 
       [0003]    Fluid systems are a key part of current medical treatment. Fluid systems are used to deliver intravenous (IV) medications, blood and blood components, nuclear medicine agents, and a variety of other liquids/fluids. Fluid systems are also used as the transport conduits for blood and body-fluid circulation equipment including transfusion apparatus, blood filters and warmer mechanisms, and blood dialysis units. The elements of a medical fluid system include a variety of conduits (e.g. flexible polymeric tubing), subcutaneous injection devices (catheters, needles, etc.), valves (e.g. stopcocks), storage and delivery devices (e.g. syringes, IV fluid bags, fluid pumps, etc.), and fluid couplings (e.g. male and female ports) for interconnecting the components of the system. In particular, fluid couplings for medical applications are designed to be easy to connect and disconnect, non-leaking, and manufactured from materials (e.g. transparent, translucent and opaque polymers) and processes (e.g. injection molding, extrusion, etc.) that contemplate disposability after use. A ubiquitous medical fluid coupling system uses threaded female ports and male couplings that engage in a “luer taper” relationship. The parameters and performance of this coupling system is particularly specified under American National Standards Institute (ANSI) standard ANSI/HIMA MD70.1, and also under the similar International Standards Organization (ISO) standard ISO 594. As described in further detail below, this system employs a female port having a proximal end in connection with a fluid system component (tubing, stopcock body, etc.) and a short external thread section on the opposing distal end. The inner surface of the distal end is formed with a somewhat tapered frustoconical shape, which is adapted to receive and seal against the distal end of a conforming male tapered or frustoconical coupling. The opposing proximal end of the male coupling is also interconnected with a fluid system component (tubing, syringe body, etc.). The male and female coupling ports are locked into a fluid-tight and air-tight relationship by an internally threaded nut or axial portion that rotates freely on a flange of the male coupling. Appropriate rotation of the axial portion with respect to the external thread section on the female port drives the male coupling axially into firm engagement with the female port with the two mating elements in a wedged-together relationship due to their respective, conforming tapers. 
         [0004]    Although fluid system coupling ports are manufactured and delivered in sterile condition, the problem of fluid system bacterial contamination is well-described in the medical literature. See by way of background Mermel, L.,  Prevention of Intravascular Catheter - Related Infections,  Annals of Internal Medicine 2000; 132:391-402; O&#39;Grady, N. et al.  Guidelines for the prevention of intravascular catheter - related infections.  Centers for Disease Control and Prevention. MMWR Morb Mortal Wkly Rep 2002; 51(RR-10): 1; Pittet, D., Tarara, D. and Wenzel, R. P.,  Nosocomial Bloodstream Infection in Critically Ill Patients,  JAMA 1994; 271, 1598-1601; Edgeworth, J., Treacher, D. and Eykyn, S.,  A  25- year Study of Nosocomial Bacteremia in an Intensive Care Unit,  Crit. Care Med. 1999; 27:1421-1428; and Laupland, K. B., Zygun, D. A., Davies, D., et al.,  Population - based Assessment of Intensive Care Unit - acquired Bloodstream Infection in Adults: Incidence, Risk Factors, and Associated Mortality Rate,  Crit. Care Med., 2002; 30:2462-2467. 
         [0005]    If the port of an intravenous fluid system becomes contaminated with bacteria, the sterility of the entire fluid system is compromised and provides a direct, intravenous, route for introduction of harmful bacteria into the patient. As reported in the above-referenced background publications, there are an average of 5.3 hospital-acquired bloodstream infections per 1000 catheter days in the intensive care unit. Each hospital-acquired bloodstream infection is associated with an approximate mortality rate of 10-35%. Additionally, hospital-acquired bloodstream infections are associated with longer hospitalizations, and impose a significant economic burden. In one current estimate, each hospital-acquired bloodstream infection costs $34,508-$56,000, resulting in an annual cost of $296 million to $2.3 billion annually. An estimated 250,000 cases of hospital-acquired bloodstream infections occur yearly in the United States. Alarmingly, hospital-acquired bloodstream infections have become more frequent, according to one 25-year study referenced above, most likely as a result of the increased use of intravascular catheters, which are the most common source of bloodstream infection. Clearly, contaminated intravenous systems which result in bloodstream infections cause significant mortality, increased length of hospital stay and a considerable economic burden. 
         [0006]    The existing design of female medical coupling ports may, in fact, increase the risk of hospital-acquired bloodstream infections. By way of background, reference is now made to  FIGS. 1 and 2 , which respectively show a perspective and side view of a conventional three-port, four-way stopcock  100  containing two female ports  110 ,  112  and one male coupling port  114 , constructed in accordance with the above-described ANSI or ISO standard for a luer taper system having a threaded “luer lock” arrangement according to the prior art. An exemplary version of this stopcock is shown and described in U.S. Pat. No. 6,418,966, entitled STOPCOCK FOR INTRAVENEOUS INJECTIONS AND INFUSION AND DIRECTION OF FLOW OF FLUIDS AND GASSES, by George Loo, the teachings of which are incorporated herein by reference as useful background information. The stopcock  100  includes a main housing or body  120  that, like other medical fluid system fittings to be described herein, can be constructed from a biocompatible polymer, such as polycarbonate, acrylic, polyvinylchloride (PVC) or acrylonitrilebutadienestyrene (ABS), using injection molding or another suitable construction technique. The body includes a central chamber  120  that is connected by passages (not shown) to each port  110 ,  112 ,  114 . The passages are sealed and/or interconnected to allow fluid flow by one or more channels formed through a core (not shown) that is rotatably mounted in the chamber  120 . The core&#39;s passages can be rotated to align with the passages of ports to interconnect the flow between selected ports. Alternatively, the core can be rotated so that passages are sealed with respect to each other, thereby stopping fluid flow through the stopcock  100 . The core is rotated (curved double arrow  210 ) using a lever assembly  130  that includes an extended lever  132 . The lever  132  is adapted to be engaged by one or more fingers of the practitioner, and thereby rotates the core about a rotation axis  220  with respect to the chamber  120  to achieve the desired flow setting. 
         [0007]    Notably, the depicted female ports  110 ,  112  include the axially short external thread section  134 ,  136 , respectively, surrounding a tapered female port orifice/passage  140 ,  142  (also shown in phantom in  FIG. 2 ). The male coupling port  114  in this example includes an internally threaded locking sleeve (or nut)  150  seated upon the male coupling  152 . As shown further in  FIG. 2 , the taper angle TA conforms to the taper of the female port orifice ( 140 ,  142 ) allowing male luer fittings and female luer firings to be nested (generally wedged together) coaxially in a sealed relationship. In this example, the internally threaded (internal threads  156 ) locking sleeve  150  of the male coupling port  114  rotates freely about the male coupling  152 , but is restrained from slipping axially off the coupling by a raised ring  230  or another restraining member. In  FIG. 2  the internally threaded locking sleeve  150  is shown in phantom, as it can be omitted in so-called “luer slip” arrangements in which the male and female members are axially pressed onto each other and secured in a fluid-tight relationship by a fiction fit. In such an arrangement, the thread section of the female member can be omitted. In other arrangements, the internally threaded locking sleeve can be fixedly (non-rotatably) secured to the male coupling. Such an arrangement is common where the proximally connected element has increased rotatability, such as where the male port coupling is applied to an end of an elongated, flexible tubing. 
         [0008]    Reference is now made to  FIG. 3 , which shows the exemplary stopcock  100  in use with interconnected fluid system components  302  attached to the female port  114  by a threaded male coupling  304 . The stopcock  100  is manipulated by a practitioner whose hand  310  grasps the rotatable lever assembly  130 ,  132  with his or her thumb  312  and forefinger  314 . Note that the hand  310  is ungloved, which is typical in many procedures involving the use of a fluid system (often due to the greater dexterity required to manipulate fluid system components). Despite the practitioner&#39;s proper and diligent efforts to scrub hands with disinfectant, substantial live microbiological residue usually remains thereon, and may easily become deposited on the distal tip (and threads  136 ) of the female port  112  as the fingers glance and contact it while moving (double arrow  320 ) the lever  132  to a new position (as shown in phantom). Many other opportunities to contaminate some or all of the fluid couplings and associated components also exist. 
         [0009]    For example, to place male threaded/locking coupling (syringe, tubing end, etc.) in engagement with the port  112 , a series of steps must be carefully taken to maintain sterility. First, a sterile cap  330  having a stoppered, threaded male end  332  and a (knurled) gripping surface  334  is unscrewed from the port  112  and placed in a sterile location as shown. Next, as depicted in  FIG. 4 , the practitioner manipulates a syringe  400  with an associated male cannula, which in this example is the male luer coupling  410  with an internal thread  450  and male taper luer  460  mounted on the distal end of a syringe barrel  430  having a proximal plunger  432 . The syringe  400  is lowered (arrow  440 ) by the practitioner&#39;s hand  310  to place the distal male coupling  410  into alignment and engagement with the female port  112  and its associated female taper luer hole  142  and external thread  136 . As shown in  FIG. 5 , once the distal male coupling  410  is properly aligned, the syringe barrel  430  is then twisted (arrow  510 ) to engage the distal male coupling&#39;s internal thread  520  until it is firmly and securely locked onto the female port  112  in a fluid-tight seal. The practitioner can then deliver or withdraw a measured volume of fluid, medication, etc. by axially depressing or withdrawing (double arrow  520 ) the plunger  432  with respect to the syringe barrel  430 . Thereafter, the practitioner twists off and disconnects the syringe coupling  410  from the female port, and reconnects the cap  330  so as to prevent inadvertent leakage of fluid or subsequent contamination of the thread  136  or female luer taper orifice  142 . The recapped port  112  is shown in  FIG. 6 . Note that the presence of a standard (though blocked) female luer lock fitting  370 , with proximal external thread  372  allows a number of similar caps  330  to be stacked male-to-female end for “safe-keeping” as shown. One may even place the syringe coupling ( 410 ) or other working male luer coupling at the proximal end of this stacking arrangement  610  as also shown. 
         [0010]    Note, as used herein, terms such as “proximal” and “distal” shall refer to the relative direction of a component in the fluid system with respect to the practitioner and/or patient. The component side facing the practitioner, and into which an injection, etc. is directed, is typically “proximal”, while the component side facing the patient, or another downstream device is “distal”. However, these definitions are only conventions used to provide relative locations of a component. Likewise term such as “axial”, “up”, “down”, etc. are conventions and not absolute directions. 
         [0011]    The practitioner repeats these steps multiple times (e.g. for each medication that is delivered or fluid administered), thereby significantly increasing the risk of port contamination and patient infection due to the ever-present risk that non-sterile hands or implements will contact the port  112 . The constant handling, putting aside, and possible stacking of the small cap(s) poses another risk of port contamination. Adding to the risk of contamination, the practitioner must manually steady the sterile port with respect to the male coupling, in most instances, to establish the connection. In so doing, the practitioner&#39;s fingers may inadvertently touch the sterile port, or the male luer taper may slip off the sterile female port and touch against the fingers that are stabilizing the stopcock  100 . This renders the syringe and the potentially costly medication therein useless (or hazardous/fatal if used). As described above, for example using a stopcock, the location of the lever essentially invites finger-contact with the port. In addition, fluid ports (capped and uncapped) often lie casually against the patient&#39;s gown and/or skin between uses—and may even become dragged onto non-sterile surfaces, sometimes with threads exposed to these surfaces. 
         [0012]    As described above, the problem of fluid system contamination is well-known in the medical literature. While proper hand hygiene must be practiced to reduce hospital-acquired infections, medical device innovation may also reduce this risk. One device which can potentially reduce contamination of ports is taught in U.S. Pat. No. 5,730,418, entitled MINIMUM FLUID DISPLACEMENT MEDICAL CONNECTOR, by Feith, et al., the teachings of which are incorporated herein by reference as useful background information. The minimum fluid displacement medical coupling described therein eliminates the need for capping and recapping the female port to avoid inadvertent fluid loss therethrough by providing a self-sealing proximal female taper luer coupling tip that is adapted to connect with a standard threaded (locking) male taper luer coupling. By way of example,  FIG. 7  shows commercially available version of the minimum fluid displacement medical coupling  700 . The coupling  700 , also commonly termed a “clave”, consists of a housing  710  that includes a proximal female taper luer port end  712  with standard external threads  714  adapted to engage the locking sleeve of a male taper luer lock coupling. On the distal end of the housing  710  is a male taper luer lock coupling  720  having an internal thread  722  and male taper luer  724  with a central passage  726  that allows fluid-flow into an interconnected conventional female luer taper port (such as the fluid entry port of a stopcock, as described below). The female port  712  and male port  720  are in fluid communication via the inner chamber  730  of the housing  710 . The female port is normally sealed by a soft polymeric (rubber, for example) plug  740  that is biased into the inner wall of the port opening  742  into a sealed relationship therewith. The proximal biasing force is generated by an integral/unitary spring body  744  (defining a bellows shape) with an opposing base end  746  that rides on a central, vented guide  746  adjacent to the male port  720 . In alternate embodiments, a separate compression spring can be used to generate the proximal, sealing bias force. When, as described further below, the plug  740  is biased distally (arrow  750 ) by a fluid system taper luer end, it opens a channel between the port opening  742  and the inner chamber  730 , and thereby allows fluid to travel between the female port  712  and the passage  726  of the male port  720  of the coupling via the inner chamber  730 . Upon removal of the locked-on male taper luer from the biased plug end  712  of the coupling  700 , the plug moves back into a sealing position against the inner wall  742  of the female port, thereby preventing fluid loss. 
         [0013]    While this coupling  700  effectively avoids unwanted leakage or loss of fluid from the proximal female port  712 , this coupling, however, does not improve the precision and accuracy of making medical connections, nor does this coupling prevent inadvertent port contact with non-sterile objects or body parts. For added protection a separate (also potentially contaminated) cap must be applied to the female port. This particular exemplary minimum displacement fluid coupling also does not provide a stopcock mechanism for variable direction of fluid flow, but must be applied to the port of a conventional stopcock. 
         [0014]    Medical device innovation aimed at improving the precision and accuracy of making connections and reduction of contact with non-sterile objects may reduce contamination of fluid systems and ultimately decrease the number of hospital-acquired bloodstream infections. Accordingly, it is highly desirable to provide a system that functions to improve the precision and accuracy of establishing a medical fluid coupling and that protects the sterile nature of the fluid port from contact with non-sterile objects with the ultimate goal of reducing patient infections. This system should be fully compatible with existing luer-taper and similar friction-fit and threaded coupling systems and should integrate with either conventional ports or minimum displacement fluid coupling ports. The system should also be applicable to a variety of medical fluid system components and couplings including stopcocks of various types, IV interfaces/spike connections, injection ports, tubing couplings and adapters, and the like. 
       SUMMARY OF THE INVENTION 
       [0015]    This invention overcomes the disadvantages of the prior art by providing a female medical coupling port with an integrated port guide to enable more accurate and precise coupling of a male port coupling (such as the cannula of a syringe) and to prevent port exposure to non-sterile objects. The male and female ports can be arranged according to standard dimensions for male and female luer taper fittings recognized by ANSI and by ISO. Thus, this guide-shielded port is usable with the standard ANSI and ISO male cannula widely used in the medical field. In an embodiment, the female port is used in medical fluid systems to receive a blunt male cannula, such as those found in the luer lock fitting of needle-less syringes and IV tubing systems to establish a mechanical coupling. Standard male luer lock fittings have a male luer taper surrounded by a threaded locking collar or sleeve which enables coupling with female ports. Female ports allow coupling of devices (e.g. syringes and IV tubing) to a variety of medical applications including stopcocks, minimum fluid displacement medical couplings, female-to-female adapters, port dead-end caps, IV extension sets, pressure-monitoring devices, epidural or intrathecal catheter tubing, etc. The port guide can be constructed as a unitary part of the port, or can be a retrofittable structure that is either snapped into place on, for example, a female port stem, or slid onto a port, such as a minimum displacement fluid coupling (clave). 
         [0016]    In an illustrative embodiment, the medical fluid coupling comprises a female port of a first medical fluid system component including a proximal port end that is constructed and arranged to sealingly engage a male port coupling. A port guide defines a sidewall that surrounds the female port and extends from a distal end of the female port to a proximal guide end. The proximal guide end is open to receive the male port coupling and located proximally at a spacing from the proximal port end, so as to prevent contaminating contact with the female port and aid to in guiding the male port coupling into alignment and engagement with the proximal port of the female port. The female port can comprise a female luer taper port and the male port can comprises a male luer taper port in which the proximal port end can define an external locking thread and the male port defines an internally threaded collar or sleeve, surrounding a luer taper connector tip. The threaded collar or sleeve is constructed and arranged to threadingly engage the external thread. The luer taper geometry of the male/female ports and the thread dimensions can be in accordance with ANSI and/or ISO specifications. 
         [0017]    In an illustrative embodiment, the female port includes a housing on a distal region thereof comprising a minimum fluid displacement coupling and the proximal port end includes a movable self-sealing plug therein. The guide can be adapted to removably slide onto the housing, or can be formed unitarily with the coupling. In another illustrative embodiment, typically applicable to ports that include a stem and threaded proximal end, the port guide can include a pair of axially spaced apart resilient central supports, such as O-rings, having an un-flexed inner diameter equal to or slightly less than the outer diameter of the stem. The O-rings are adapted to flexibly pass over the threaded portion and captures the distal stem of the port-thereby providing a retrofittable structure that can be used with the conventional ports of stopcocks and other fluid system components. Appropriate drain ports can be provided to channel fluid away from the proximal region above the O-rings/resilient central supports. Other attachment and fixing mechanisms, such as the use of a guide with clamshell halves or a separate attachable mounting base can be employed in alternate embodiments to provide an attachable/retrofittable port guide to a port structure. 
         [0018]    In various embodiments herein, the port guide defines, at a proximal region thereof, an outward taper in the proximal direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The invention description below refers to the accompanying drawings, of which: 
           [0020]      FIG. 1 , already described, is a perspective view of a conventional three-port four-way stopcock including male and female taper luer ports according to the prior art; 
           [0021]      FIG. 2 , already described, is a side view of the stopcock of  FIG. 1 ; 
           [0022]      FIG. 3 , already described, is a diagram showing the stopcock of  FIG. 1  interconnected with a medical fluid system, and the lever thereof manipulated by the hand of a practitioner in a manner that risks microbiological contamination of a fluid-entry port; 
           [0023]      FIG. 4 , already described, is a diagram showing the stopcock and fluid system of  FIG. 3 , and a syringe with a conventional male taper luer coupling being brought into connection with a female luer taper port of the stopcock by the hand of a practitioner in a manner that risks microbiological contamination of a fluid-entry port; 
           [0024]      FIG. 5 , already described, is a diagram showing the stopcock and fluid system of  FIG. 3 , with the male taper luer coupling of the syringe in connection with the female luer taper port of the stopcock; 
           [0025]      FIG. 6 , already described, is a diagram showing the stopcock and fluid system of  FIG. 3 , with the male taper luer coupling of the syringe disengaged from the female luer taper port of the stopcock and a plurality of caps stacked onto the female luer taper port of the stopcock; 
           [0026]      FIG. 7 , already described, is a side cross section of a minimal fluid displacement coupling including a self-sealing, minimum fluid displacement medical coupling with opposing male and female luer taper lock couplings according to the prior art; 
           [0027]      FIG. 8  is a top view of a three-port, four-way stopcock including a threaded, locking female taper luer port with a contamination-reducing port guide according to an illustrative embodiment of this invention; 
           [0028]      FIG. 9  is a partial cross sectional perspective view of a three-port four-way stopcock including a pair of threaded, locking female taper luer ports each with a contamination-reducing port guide according to an illustrative embodiment of this invention; 
           [0029]      FIG. 10  is a diagram showing the illustrative stopcock of  FIG. 8  interconnected with a medical fluid system, and a syringe with a conventional male taper luer coupling being brought into connection with the female luer taper port with the contamination-reducing port guide; 
           [0030]      FIG. 11  is a diagram showing the illustrative stopcock of  FIG. 8  interconnected with a medical fluid system, and the syringe coupled with the female luer taper port with the contamination-reducing port guide; 
           [0031]      FIG. 12  is a diagram showing the illustrative interconnected stopcock of syringe arrangement of  FIG. 11  with the stopcock manipulated by one hand of the practitioner while another hand operates the syringe plunger with the port area protected from contamination by the port guide; 
           [0032]      FIG. 13  is a diagram showing the illustrative stopcock of  FIG. 8  interconnected with the medical fluid system, with a smaller-diameter syringe coupled with the female luer taper port with the contamination-reducing port guide; 
           [0033]      FIG. 14  is a diagram showing the illustrative stopcock of  FIG. 8  interconnected with the medical fluid system, with a larger-diameter syringe coupled with the female luer taper port with the contamination-reducing port guide; 
           [0034]      FIG. 15  is a partial perspective view of a series of interconnected stopcocks that are part of a fluid system resting on a patient&#39;s gown while receiving treatment therefrom, with reduced risk of contamination from the environment; 
           [0035]      FIG. 16  is a perspective view of an illustrative three-port, four-way stopcock including a threaded, locking female taper luer port with a contamination-reducing port guide being interconnected with a conventional male taper luer connector with threaded locking sleeve; 
           [0036]      FIG. 17  is a perspective view of a threaded, locking female taper luer port mounted as an end connector on a flexible tubing, and including a contamination-reducing port guide being interconnected with a conventional male taper luer connector with threaded locking sleeve, according to an illustrative embodiment; 
           [0037]      FIG. 18  is a perspective view of an IV bag spike connection including a threaded female luer taper coupling port according to the prior art; 
           [0038]      FIG. 19  is a top view of the IV bag spike of  FIG. 18 ; 
           [0039]      FIG. 20  is a perspective view of an IV bag spike including a threaded, locking female taper luer port with a contamination-reducing port guide according to an illustrative embodiment of this invention; 
           [0040]      FIG. 21  is a top view of the IV bag spike of  FIG. 20 ; 
           [0041]      FIG. 22  is a diagram showing the insertion of the IV bag spike of  FIG. 19  into an exemplary IV bag and associated interconnection of the female taper luer port of the spike with a male taper luer coupling on an IV system tubing; 
           [0042]      FIG. 23  is a side cross section of a minimum fluid displacement coupling including a contamination-reducing port guide according to an illustrative embodiment of this invention; 
           [0043]      FIG. 24  is a side cross section showing the illustrative minimum fluid displacement coupling with port guide of  FIG. 23  interconnected with an exemplary syringe having a threaded male taper luer coupling; 
           [0044]      FIG. 25  is an exploded perspective view of a minimum fluid displacement coupling and associated port guide according to an illustrative embodiment shown mounted on the female luer taper port of an exemplary conventional three-port, four-way stopcock and interconnected medical fluid system; 
           [0045]      FIG. 26  is a perspective view of the minimum fluid displacement coupling and port guide of  FIG. 25 , shown assembled and mounted on the female luer taper port of an exemplary conventional three-port, four-way stopcock; 
           [0046]      FIG. 27  is a diagram showing the illustrative stopcock and minimum fluid displacement coupling with port guide according to  FIG. 26  interconnected to the medical fluid system, with a smaller-diameter syringe coupled thereto; 
           [0047]      FIG. 28  is a diagram showing the illustrative stopcock and minimum fluid displacement coupling with port guide according to  FIG. 26  interconnected to the medical fluid system, with a larger-diameter syringe coupled thereto; 
           [0048]      FIG. 29  is a side cross section of a medical fluid system tubing having a minimum fluid displacement coupling and port guide attached thereto, and interconnected with a threaded male luer taper coupling attached to another medical fluid system tubing, according to an illustrative embodiment; 
           [0049]      FIG. 30  is a perspective view of an attachable port guide for use with conventional threaded female luer taper coupling ports according to an illustrative embodiment; and 
           [0050]      FIG. 31  is a fragmentary perspective view of the illustrative attachable port guide of  FIG. 30  installed on a threaded female luer taper port of an exemplary three-port, four-way stopcock and having attached thereto an exemplary syringe. 
       
    
    
     DETAILED DESCRIPTION 
       [0051]      FIG. 8  is top view of a three-port, four-way stopcock  800  with a conventional rotating (double curved arrow  812 ) lever assembly  810  having a conventional externally threaded female luer taper port  820  and opposing male luer taper port  822  (with threaded locking sleeve omitted). A third, externally threaded female luer taper port  830 , typically positioned at a syringe-coupling location, is also provided in accordance with an illustrative embodiment. This port  830  includes a stem  832  extending proximally from the stopcock&#39;s central chamber  840  (which houses the core of the lever assembly  810 ). The stem  832  ends in a conventional, axially shortened external luer lock thread  850 . The thread surrounds a luer taper orifice and passage  852  (shown in phantom) as described above. 
         [0052]    Notably, the female port stem  840  is surrounded by a port guide  860  in accordance with an illustrative embodiment. The port guide  860  in this embodiment is constructed from a polymer that is shown as transparent. In alternate embodiments, the port guide and/or other parts of the stopcock can be constructed from translucent or opaque materials. Note that where a polymer is used to construct the port guide and/or other portions the fluid system component it can be of an antimicrobial type, including appropriate antibacterial fillers and additives. The port guide extends from the central chamber  840  to a proximal edge  862  residing axially/proximally beyond the proximal end of the port thread  850 . This additional distance of proximal extension DPE is highly variable. In an illustrative embodiment it is between approximately 2 and 6 millimeters. As described further below, the distance DPE should be sufficient to provide overlapping coverage for the port/thread&#39;s proximal end  854 , but not so long as to prevent a conventional male luer taper cannula of a syringe, for example, from fully seating onto the female port. In order to provide clearance from such a male cannula, a radial spacing RS is also established between the maximum outer perimeter of the thread  850  and the inner wall of the port guide  860  in its proximal region  864 . This radial spacing RS is sufficient to accommodate the thickness and maximum outer diameter of a conventional male luer lock internally threaded sleeve. In an embodiment, RS is at least approximately 2-5 millimeters. However, this distance is highly variable so long as the distance RS is sufficient to accommodate the thickness and outer diameter of the thickest/largest-diameter diameter male cannula/coupling to be accommodated by the port  830 . The proximal region  864  of the port guide  860  is optionally flared to a larger diameter as shown to provide the cannula clearance distance RS in the region of the thread. The clearance (RS) should extend distally (toward the central chamber  810 ) past the thread  850  by a distance DC that allows the distal tip of the longest locking cannula threaded sleeve to remain unobstructed when the cannula is fully locked onto the port  830 . In an embodiment, the distal clearance DC is at least between approximately 4 and 10 millimeters. However, a longer extension distance of the large-diameter region of the port guide is contemplated, and in alternate embodiment, the larger inner port guide diameter can extend to the central chamber. In an embodiment this inner diameter is between at least approximately 9 and 12 millimeters, but larger (or somewhat smaller) port guide inner diameters are expressly contemplated. 
         [0053]    Reference is now made to the partial cross-sectional view of a similar stopcock  900  to that ( 800 ) shown in  FIG. 8 . This illustrative stopcock  900  includes a central chamber  910  with rotating lever assembly as described above. It also includes a male luer taper port  922  with internally threaded locking sleeve  924 . Notably, this embodiment includes a pair of externally threaded female luer taper ports  930  and  940  each with corresponding, surrounding port guides  950  and  960 , respectively. The guides exhibit inner diameters and clearances that are generally in accordance with the dimensions described above. 
         [0054]    In this embodiment, the proximal region  952 ,  962  of each respective guide  950 ,  960  is provided with a proximally outward flare or taper such that the proximal end  954 ,  964  is of larger inner diameter than the region adjacent to the port thread  932 ,  942  is of a slightly smaller diameter. This enhances the ability of the port guide  950 ,  960  to assist the practitioner in more accurately and precisely aligning a male cannula with the female port by providing, in essence, a funnel effect. The angle of the taper (GTA) with respect to the axial (distal-to-proximal) direction can vary greatly. In an embodiment, the angle GTA is between approximately 2 degrees and 10 degrees. However other taper angle ranges are expressly contemplated. Likewise the flare or taper may be provided only along a portion of the proximal region (e.g. a short funnel end), so long as the more distal remainder of the region provides an inner diameter with needed clearance for the cannula. Alternatively the taper can be carried beyond the proximal region, and optionally to the central chamber or other component base to which the port guide and/or port stem is attached. Furthermore, the taper need not be a single angular dimension (i.e. a frustoconical shape), but alternatively can define a compound angle and/or curvilinear bowl shape. Additionally, the radially directed wall thickness WT of the port guide in any embodiment herein can be highly variable. In an embodiment, the thickness WT is between approximately 0.5 and 3.5 millimeters, but other dimensions are expressly contemplated and should afford sufficient structural strength to the port guide with respect to the material being used to construct it. In various embodiments, the proximal edge and/or another portion of the guide can include one or more strengthening ribs or lips that define thickened portions. For example, as depicted in various embodiments herein, the proximal edge includes a radially thickened lip. 
         [0055]    Notably, it is contemplated that the port guide could potentially retain excess fluid from a fluid-delivery or fluid-withdrawal in proximity to the stem and port—potentially contaminating these elements. Thus, the port guides  950 ,  960  are provide with one or more through-cut drain ports  970  at various locations about the circumference of each guide and at various locations along the length of the guide. These holes are large enough in opening area to rapidly drain any excess fluid captured by the port guide during a procedure, but small enough to prevent infiltration of foreign matter during handling. For example, holes having a diameter of 0.5-1.5 millimeters can be employed in an embodiment. In illustrative embodiments, drain ports  970  can be located as close as possible to the distal base of each guide where the inner diameter of the port guide initially defines an inner hollow region or chamber. Drain ports  970  can also be located at additional locations along the guide&#39;s wall to ensure more rapid and efficient draining of fluid when it reaches a heightened level within the space between the guide&#39;s inner wall and the port stem. The size, shape, number and position of drain ports are all highly variable. While depicted as rounded holes, the ports can define polygonal slots, elongated grooves, and the like. For example, in an alternate embodiment, the drain ports can define a set of narrow slots located at predetermined positions around the circumference of the port guide extending from the base to a proximal position below the level of the port proximal end. A variety of alternate drain port arrangements are expressly contemplated. 
         [0056]    The port guide according to various embodiments herein can be constructed by a variety of techniques, and provided to the underlying female luer taper port in a variety of manners. For example, where the guide is constructed as a separate unit to be subsequently attached to the fluid system component, it can be constructed from extrusion, molding (injection molding, blow-molding, etc.) or machining from solid stock. Such a separate port guide is then attached and permanently or removably adhered to the underlying fluid system component using friction fit, snap fit, adhesives, welding (ultrasonic, for example), fasteners, or other suitable attachment techniques and mechanisms. In other embodiments, in which the port guide is unitary with the underlying fluid system component and port, it can be formed thereon by molding, machining, extrusion (typically in the case of a linear or tubular component), and/or other techniques that facilitate formation of a nested shape with the port guide surrounding, and extending proximally beyond, the proximal end of the female port. 
         [0057]    Reference is now made to  FIG. 10 , which shows the use of the port guide  860  on the above-described stopcock  800  (depicted in an interconnection with a medical fluid system  1010 ) in conjunction with a conventional injection syringe  1020  with a plunger  1020  movable axially (double arrow  1024 ) within the syringe barrel  1026  so as to direct or withdraw fluid via the distal cannula  1030 . In this example, the cannula is a conventional male luer taper coupling with an internally threaded (threads  1032 ) outer sleeve  1034  and coaxial, distally projecting male luer coupling  1036 . As shown, the practitioner can bring the cannula  1030  into and out of engagement (double arrow  1040 ) with the port guide opening  1030  and its surrounding proximal edge  862 . The increased inner diameter DGI of the port guide&#39;s proximal edge  862  relative to the outer diameter DCO of the cannula  1030  assists in guiding the cannula toward the port thread  850 , with the male luer taper coupling  1036  being funneled into engagement with the female port orifice/passage  852 . Once the cannula  1030  resides within the surrounding guide it will not easily jump out or inadvertently slip onto the practitioner&#39;s other hand (which is manipulating the stopcock  800  as shown in  FIG. 12 ), while the barrel  1026  of the syringe  1020  is twisted to lock the threads  550 ,  1032  into engagement. This fluid-sealed/fluid-tight engagement is shown in  FIG. 11  wherein the syringe barrel  1026  has been fully twisted (curved arrow  1110 ) to sealingly engage the cannula with respect to the female port  830 . In this orientation, the cannula is fully, or nearly fully, surrounded by the port guide wall, thereby substantially protecting it from contact or infiltration of contamination. As described above, the proximal extension of the proximal region  864  of the port guide above the proximal end of the port  830  is chosen to ensure that the syringe barrel  1026  is not interfered with by the proximal edge  862  of the guide, regardless of the outer diameter DS of the barrel  1026 . Hence the distal shoulder  1060  between the syringe barrel  1026  and the cannula  1030  resides at least slightly spaced-apart from the guide&#39;s proximal edge  862  when the cannula is fully tightened onto the female port as shown in  FIG. 11 . In alternate embodiments, the proximal edge can be sized and arranged to overlap part of the syringe barrel-at least for syringe barrels having a predetermined maximum diameter DS. 
         [0058]    It should be clear that the illustrative port guide  860  effectively isolates the port  830  from contamination under a variety of circumstances. Notably, and as shown in  FIG. 12 , the practitioner&#39;s hand  310  can effectively and firmly grasp and manipulate the stopcock, free of the risk of inadvertently contacting a portion of the port. In fact, the port guide  860  defines another convenient gripping surface when administering an injection—as shown, pushing (arrow  1210 ) the plunger  1022  with the opposing hand  1222 —or manipulating the lever assembly  810 . When the syringe  1020  is disconnected or removed, the port ( 830 ) the proximal end of the port is recessed so that the risk of contact with contaminants is significantly lessened. In fact, the inner diameter of the port guide combined with the distal offset of the port from the proximal edge of the guide may render contact with the port by normal adult fingers nearly impossible. Likewise, even if the port guide&#39;s proximal edge is stood on edge against a non-sterile surface, the contamination cannot reach the port. Of course where the edge is exposed to contamination, care should be taken to avoid contacting the cannula with the exterior of the guide. However this is a significantly easier goal to achieve for most practitioners than attempting to align an unguided male cannula on a female port. 
         [0059]    As described above, the proximal region  864  of the exemplary port guide is sized and arranged to accommodate a standard-sized cannula for syringes (and other fluid system components having male couplings) regardless of the external dimensions (diameter DS of the syringe barrel (or other component). With reference to  FIG. 13 , a syringe  1310  having a small-diameter (DSS) barrel  1320  is shown with its cannula  1330  threadingly engaged to the port  830 . The diameter DSS is the same or slightly larger than that of the cannula, and thus, the syringe  1310  passes easily into the proximal region   864  of the port guide  860  with extra clearance room. Nevertheless, the risk of contamination to the port is still significantly reduced, both when the syringe  1310  is engaged and disengaged. 
         [0060]    Likewise, as shown in  FIG. 14 , a syringe  1410  having a large-diameter (DSL) barrel  1420  is shown threadingly engaged to the port. The barrel diameter DSL is significantly larger than that of the cannula (not shown), however, the distal end of all syringes (regardless of the barrel diameter) are generally standardized, conforming to ANSI and ISO measurement standards. Therefore, the larger-diameter syringe will fit free of interference into the proximal region  864  of the port guide  860 . The location of the guide&#39;s proximal edge  862  combined with the standardization of male luer taper components ensures that the shoulder  1430  between the cannula section of the syringe and the large-diameter barrel remains at leased slightly spaced-apart from the port guide  860  (and proximal edge  862 ) when the syringe  1410  is fully twisted onto the stopcock female luer taper port. The guide is particularly beneficial in easing the task of guiding and aligning (funneling) a large, and high-volume syringe, which may otherwise prove difficult to manipulate onto the small female port fitting. 
         [0061]    As shown in  FIG. 15  the benefits of a medical fluid system  1500  containing port guides  1510  in accordance with an illustrative embodiment become even more apparent. As shown, each interconnected stopcock  1520  in the system  1500  includes a practitioner-accessed port with a guide thereon. As is often typical the stopcocks  1520  rest as a unit on the patients&#39; chest/garment  1530 . The practitioner (hand  1550 ) can administer fluid/medication or withdraw fluid via the syringe  1540  in interconnection with a port of the system  1500  with reduced risk of contamination. When disconnected, the ports are shielded by the guides  1510  from contamination by the patient&#39;s garment or skin, or that of surrounding surfaces and persons. 
         [0062]    The port guide  860  is sized and arranged to receive a variety of threaded sleeves for male taper luer connectors, as described generally above. With reference to  FIG. 16 , the above-described stopcock  800  and associated female taper luer port  830  and port guide  860  is adapted to receive (arrow  1610 ) a conventional male taper luer coupling  1620  with rotating internally threaded sleeve  1630  mounted at the distal end of a conventional flexible medical fluid tubing  1640 . The tubing&#39;s distal end includes a male luer taper coupling  1650  sized and arranged to sealingly engage the female port orifice  852 . The inner diameter DGI of the proximal region  864  of the port guide  864  is greater in diameter that the outer diameter DMC of the threaded sleeve  1630 , including any outward protuberances (e.g. grip surfaces, knurling, etc.) thereof. In general, the distal proximal extension (DPE in  FIG. 8 ) of the port guide is selected so that a portion of the sleeve  1630  having an axial height/length HMC remains grippable, even when fully engaged on the thread  850 . In alternate embodiments, the height/length HMC can be lengthened, or additional proximal gripping surfaces (for example molded-on or applied tabs or wings) can be provided to proximally extend the gripping surface where the majority of the sleeve is embedded into the guide&#39;s proximal region  864  during engagement with the port  830 . 
         [0063]    It should be clear that the illustrative port guide in accordance with various embodiments of this invention can be employed with a variety of female luer taper ports, attached to various medical fluid system components. As shown in  FIG. 17 , a flexible tubing  1700  for a medical fluid system can include a distal end having a female luer taper port  1710  as described generally herein. The port is surrounded by an appropriately sized port guide  1720  of sufficient inner diameter-the size of the inner diameter being in accordance with the dimensions described herein particularly in the proximal region  1722  between the (optionally) flared proximal end  1730  and the area directly distal of the port thread  1740 . These dimensions allow the reception and threading engagement of an internally threaded sleeve  1750  of conventional or modified design (e.g. modified to extend axial length). The sleeve in this embodiment is attached to a conventional male luer taper coupling  1752  that is in fluid communication with a second fluid tubing  1760 . However, the sleeve  1752  and male luer taper coupling can be attached to any appropriate fluid system component that is desirably connected with the port  1710 . Some exemplary components  1770  that can be combined with or substitute for the tubing  1700  are described. These fluid system components ( 1770 ) include, but are not limited to IV systems or IV extension sets, female-to-female adapters, fluid/blood pressure and/or fluid/blood chemistry monitors, syringes, pumps and/or other fluid-delivery/withdrawal devices, stopcocks and valves, fluid filtration and fluid warming devices, all defined generally as “fluid handling devices”. 
         [0064]    A further use for the port guide according to embodiments of the invention is shown with reference to  FIGS. 18-22 . A common element in medical fluid systems is an intravenous (IV) bag or container, which can contain any of a variety of medical fluids for administration to the patient by well-known IV infusion procedures. As shown in  FIGS. 18 and 19 , the fluid interface for an IV fluid bag is the so-called IV spike  1800 . The IV spike can also be used to withdraw fluid from a container into a syringe. The spike  1800  consists of a base plate  1810  used for securing the spike against the bag or container (i.e. bottle of medication) (described below), and a sharpened unitary shaft  1820  with a central lumen that passes into a proximal connector  1830 . The connector defines a threaded female luer taper coupling in this embodiment. Note that the thread  1832  defines a pair of opposing teeth that are circumferentially interrupted in this embodiment. A substantially circumferentially continuous thread can be provided in alternate examples. At the connector end, the lumen  1822  defines a female luer taper orifice  1910  that is adapted to mate coaxially with a conventional threaded male luer taper coupling and internally threaded locking sleeve. This prior art spike structure, like other unshielded port structures is subject to potential contamination—particularly when reconnected to the fluid system over multiple cycles, but even after a single connection event in which the port  1830  is exposed to contamination. As shown, the spike  1800  can contain a side connection  1930  in fluid communication with the lumen  1822 , with the use of air vent  1852  to prevent the creation of a vacuum during the transfer of fluid. 
         [0065]    With particular reference to  FIGS. 20 and 21 , an IV bag or container (e.g. medication bottle) spike connection  2000  according to an illustrative embodiment is detailed in perspective and top views. This spike  2000  includes a base plate  2010  a sharpened shaft  2010  with central lumen  2022  as described above. The lumen  2022  is in fluid communication with the orifice  2112  a female luer taper port  2110  having a proximal thread  2114  for engaging the internal thread of a male luer taper locking sleeve  2210  ( FIG. 22 ). The lumen  2022  is interconnected with an optional side port covered by a cap  2030  in this embodiment. The port  2110  is surrounded by a port guide  2050 . The inner dimensions of the port guide  2050  are similar or identical to the embodiments described hereinabove. In general, the proximal end  2060  and adjacent proximal region extend proximally past the port  2110  to fully cover it against inadvertent contact, and defines an inner diameter over an applicable axial distance with respect to the thread  2114  that receives and accommodates a male internally threaded sleeve  2210 . 
         [0066]    As shown further in  FIG. 22 , the shaft  2020  of the spike  2000  is inserted (arrow  2220 ) into a port  2230  of an exemplary IV fluid bag  2240 . The internally threaded sleeve  2210  of a male taper luer coupling  2250  is, likewise, interconnected (arrow  2260 ) to the spike&#39;s port ( 2110 ) by the threaded interconnection therebetween. This places the attached medical tubing  2270  into fluid communication with the spike  2000 . 
         [0067]    The disadvantages of a minimum fluid displacement coupling, as described above, can be addressed using a port guide in accordance with an embodiment of this invention.  FIG. 23  shows an assembly  2300  including a minimum fluid displacement coupling  2310  enclosed within a port guide  2320  according to an illustrative embodiment. The coupling  2310  includes a housing  2330  that encloses a spring-biased plug  2332  that selectively seals the threaded female luer taper port  2340  against fluid flow with respect to the opposing male taper luer port  2350 . The arrangement and function of the minimum fluid displacement coupling  2310  is similar or identical to the exemplary prior art coupling  700  as described above. However, the coupling can be constructed with a variety of alternate shapes and internal mechanisms according to alternate embodiments, and for the purposes of the illustrative embodiments, it is desired mainly that the coupling allow for a self-sealing coupling port at one end. As such, the opposing end can be integrally or unitarily connected to a fluid component, such as a stopcock, or the opposing end can be a removable threaded coupling (e.g. male coupling  2350 ) as shown. In this embodiment, the port guide  2320  is mounted against the base  2360  of the minimum fluid displacement coupling  2310  and defines a space  2362  between the inner wall of the port guide  2320  and the outer wall of the coupling  2310 . Where the space is present, appropriate drain ports can be provided near the base  2360  and proximally spaced therefrom. In alternate embodiments, the space can be omitted, so long as the proximal region  2364  of the port guide defines a sufficient inner diameter PID to accommodate the outer diameter of the largest threaded sleeve or cannula to be received by the female port  2340  and its external thread  2366  external thread. The port thread  2366  ends at a distal shoulder  2368 . The proximal region  2364  should maintain the sufficient inner diameter PID proximally of this shoulder  2368 . In this embodiment, the proximal region flares outwardly in the proximal direction, thereby providing a funnel-like effect for an approaching cannula. The relative angle of the taper or flare with respect to the axial direction, and its particular geometric shape, are highly variable. Likewise, the distance that the proximal edge  2370  of the port guide  2320  extends beyond the proximal edge  2372  of the female port  2340  is variable. In an embodiment, a distance of extension between approximately 5 and 8 millimeters provides sufficient clearance for the shoulders of syringes and other male couplings while preventing inadvertent contaminating contact with the port  2340 . 
         [0068]    As depicted in  FIG. 24 , a small diameter syringe  2400  with a body  2410 , plunger  2420  and distal cannula  2430  having an internal threaded sleeve  2432  and male luer taper coupling tip  2430  is twisted into full engagement with the female luer taper port  2340  of the assembly  2300 . The coupling tip  2434  depresses the plug  2332  against the biasing force of its interconnected spring portion  2450 , which is shown under compression. This allows fluid to pass through the coupling&#39;s housing and into the opposing port  2350 . When the syringe  2400  is untwisted from the port  2340 , the spring  2450  will bias the plug  2332  back into a sealed orientation, preventing fluid leakage therefrom. Meanwhile, the surrounding port guide  2320  prevents contamination of the port  2430  while providing an additional gripping surface for the practitioner to employ while twisting and untwisting the syringe or other connected fluid system component. 
         [0069]      FIGS. 25 and 26  show an embodiment of an assembly  2500  consisting of a conventional minimum fluid displacement coupling  2510  with an attached port guide  2520 . In this embodiment, the conventional coupling  2510  includes (in addition to a self-sealing threaded female luer taper port  2511 ) a base shoulder  2510  and larger diameter base section  2514  that terminates in a distal threaded male luer taper coupling  2516 . In this example, the coupling  2516  is threadingly attached to the female luer taper coupling of port  2530  on a conventional stopcock  2532 . This stopcock is attached to a medical fluid system as shown. The smaller diameter proximal portion  2518  of the exemplary minimum fluid displacement coupling  2510  receives (arrow  2550 ) the distal end  2522  of a port guide thereover. The fully assembled version of the assembly  2500  is shown particularly in  FIG. 26  in which the distal edge  2524  of the guide  2520  engages the shoulder  2512  of the coupling  2510 . In this example, the coupling&#39;s proximal portion  2518  includes gripping protrusions  2560  that generate a small cavity between the inner wall of the guide and the outer wall of the coupling in the adjacent region. Thus one or more distal drain ports  2572  (as well as more-proximal drain ports  2574 ) are provided. In alternate embodiments, the distal edge  2524  of the guide can be constructed to allow excess fluid to run past it (using notches or other passageways). The port guide  2510  of this embodiment can be a removable component, or can be permanently attached to the minimum fluid displacements coupling  2520  using adhesives, welding, fasteners, interengaging threads and the like. In illustrative embodiments the port guide can be formed together (e.g. co-molded) with a minimum fluid displacement coupling of any acceptable mechanism and shape. 
         [0070]    Briefly, as shown in  FIG. 27 , a small-diameter syringe or other fluid component is accommodated by the port guide and coupling assembly  2500  with reduced risk of contamination of the self-sealing female luer taper port ( 2510  in  FIG. 25 ). Likewise, as shown in  FIG. 28 , the placement of the port guide&#39;s proximal edge  2810  relative to the port ( 2511 ) allows a syringe  2800  or other component with a standard cannula shape/dimension and a proximal component diameter greater than the port inner diameter to be accommodated. In this example the syringe shoulder  2820  resides out of interfering contact (or just barely in interfering contact) with the proximal edge  2810  of the guide  2520  when the syringe is twisted into full engagement with the port ( 2511 ). 
         [0071]    The minimum fluid displacement coupling  2510  and port guide  2520  of the illustrative assembly  2500  (or any other arrangement contemplated herein) can be interconnected to a variety of system components either integrally/unitarily (i.e. as a non-removable part of the component&#39;s structure), or as a selectively attachable/detachable component.  FIG. 29  details one of a variety of possible interconnections in which the assembly  2500  can be employed. As shown, the male coupling  2516  of the assembly  2500  is mounted onto a female luer taper coupling  2910  on the end of a fluid tubing  2920 . In alternate embodiments, the connection between the tubing (or other fluid system component) and the assembly can be a permanent connection or a luer slip-style connection. The opposing self-sealing threaded female luer taper coupling  2511  is threadingly attached to the internally threaded sleeve  2930  of the male luer taper connector of a fluid tubing  2940 . Since the sleeve  2930  resides even with or slightly beneath the proximal edge  2810  of the port guide  2520  in this example, the practitioner tightens the coupling sleeve  2930  to the port  2511  by applying twisting force to the exposed proximal stem  2950  that is fixedly attached to the sleeve  2930  in this example. One or more grip wings  2960  can be optionally provided to the stem at a location spaced-apart from the proximal edge  2810 . A variety of alternate mechanisms can be used to allow a shallow sleeve to be tightened onto the recesses port when surrounded by a port guide. 
         [0072]    As described above, the port guide use in conjunction with a minimum fluid displacement coupling can be constructed as an attachable/retrofittable item for use with conventional non-shielded couplings. Likewise an attachable/retrofittable port guide for use with a conventional threaded female luer taper coupling port can be provided in accordance with the embodiment shown in  FIGS. 30 and 31 . Referring to the cutaway view of  FIG. 30 , the attachable port guide  3000  is constructed from any acceptable material, such as a transparent or translucent polymer. It defines a sidewall  3010  and a distal base  3012  with a central orifice  3014  having a diameter DO greater than the diameter DT of a conventional external thread  3020  of a conventional female luer taper port  3022 . A similarly dimensioned circumferential bulkhead  3030  is located within the enclosure of the sidewall at an axially proximal spacing distance SBD that is less than the spacing ST along the stem  3022  between the stem&#39;s distal end (in this example the joint with the valve chamber  3032 ) and the distal side of the thread  3020 . The difference between SBD and ST is sufficient to position the bulkhead  3030  remote from the thread so as to avoid interference with a fully engaged cannula (see  FIG. 31 ). Notably, a central resilient support  3040  is respectively within the central orifice  3014  of the port guide&#39;s distal base  3012 . Another resilient support  3042  of similar dimension is seated within a similar orifice within the bulkhead  3030 . These resilient supports  3040 ,  3042  can be constructed from any flexible material, such as rubber, soft PVC, and the like. The supports  3040 ,  3042  can take the form of O-rings in an embodiment. In other embodiments the supports are flexible washers. In general, the supports  3040 ,  3042  are flexible enough to elastically deform as they are driven (arrow  3050 ) over the thread  3020  of the port stem  3022 . The inner diameter DRS of each resilient support is approximately equal to or slightly smaller than the outer diameter DS of the stem  3022 . In this manner, the supports engage and frictionally capture the stem, as shown in the assembled arrangement of  FIG. 31 . The proximal region  3060  (proximal of the bulkhead  3030 ) of the port guide  3000  an inner diameter sufficient to accommodate the outer diameter of a standard cannula with internally threaded male luer taper coupling  3110  (shown partially in phantom in  FIG. 31 ) of a syringe  3120  or other fluid system component. All, or a portion of the proximal section  3060  can be proximally outwardly tapered or flared as shown. 
         [0073]    In  FIG. 31 , the attached port guide is secured to the stem  3022  at two axially spaced apart locations thereby forming a secure, substantially wobble-free mounting with the guide distal base  3012  resting against the chamber  3022  of the exemplary stopcock  3130  or other fluid system component. As shown, the male coupling/cannula  3110  has sufficient clearance from the bulkhead  3030  to be fully engaged, and the syringe shoulder  3140  has clearance from the proximal edge  3070  of the guide  3000 . The frictional coefficient of the resilient support, combined with the hoop stress induced by a slightly smaller diameter with respect to the stem, ensures that the guide  3000  remains axially fixed with respect to the underlying port in all orientations. 
         [0074]    As described with respect to other embodiments herein, the port guide  3000  can be provided with drain ports  3080  along its distal base  3012 , through the bulkhead  3030  and/or on the sidewall  3010  of the guide near the distal end and/or proximally above the bulkhead  3030 —and/or at other appropriate locations. 
         [0075]    It should be clear that the embodiment of an attachable or retrofittable port guide of  FIGS. 30 and 31  has advantages in that the guide is easily attached to the port with a dingle distal motion, and that the user need not contact the interior of the guide or the exterior of the port during the attachment process-which is effectively a plug-together procedure. However, other techniques for attaching and securing an attachable or retrofittable port guide are expressly contemplated in alternate embodiments. For example, a port guide consisting of two separate molded halves can be brought together on the stem and adhered together using adhesives, etc. Likewise, a separate distal base member can be assembled on the port, and the sidewall section thereafter moved distally over the port and onto the assembled base. A variety of alternate mechanisms are also envisioned. 
         [0076]    While not shown, other ports and port-like components can benefit from the port guide arrangement of the illustrative embodiments. For example, the dead-end cap  330  ( FIG. 3 ) can be provided with a port guide that extends from the internally threaded sleeve proximally past (and surrounding) the stem  370  and thread end  372 . In this manner the thread end cannot be contaminated while the cap  330  is being handled. In this manner further stacked caps, etc. that engage the thread  372  have reduced risk of contamination. Thus, for the purposes of the description, the stem  370  and thread  372  can be considered a female “port” to which the guide can be applied. 
         [0077]    In early clinical studies it has been revealed that the use of a port guide on both a standard threaded female luer taper coupling and a minimum fluid displacement coupling has beneficial effects on the reduction of both port and effluent contamination when compared with unshielded ports. In such studies practitioners, using regular and established techniques, injected sterile saline into injection ports placed under the following conditions: (a) unshielded, (b) fitted with a port guide as described herein, (c) fitted only with an unshielded minimum fluid displacement coupling, and (d) fitted with a minimum fluid displacement coupling (clave) having an attached port guide as described herein. Microbiological culture samples were then taken from the lever, injection port and injection port-directed effluent to determine the rate of bacterial contamination associated with each type of injection port (a-d). Petri dishes were inoculated with the microbiological culture samples to evaluate the lever, injection port and port-directed effluent for sterility. The lever, which comes into contact with practitioner hands, represents an expected site of bacterial contamination (thus the high percentage of fluid system lever bacterial contamination). The lumen of the injection port and the port-directed effluent should ideally have no bacterial contamination. Thirty-six practitioners participated in the study, and results are reported as a percentage of practitioners whose levers, lumens or port-directed effluent were bacterially contaminated, comparing ports a-d. The results of the cultures are shown in the following table. By way of example: 28 of 36 practitioners contaminated the lever of the unshielded port (78%), and 6 of 22 practitioners contaminated the effluent (27%). 
         [0000]    
       
         
               
               
             
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 MICROBIOLOGICAL GROWTH 
               
             
          
           
               
                 TYPE OF PORT 
                 Lever 
                 Lumen 
                 Effluent 
               
               
                   
               
               
                 Unshielded Port 
                 78% (28/36) 
                 17% (6/36)  
                 27% (6/22) 
               
               
                 Guide-Shielded Port 
                 89% (32/36) 
                 3% (1/36) 
                  0% (0/22) 
               
               
                 Unshielded Clave 
                 78% (28/36) 
                 6% (2/36) 
                 18% (4/22) 
               
               
                 Guide-Shielded Clave 
                 75% (27/36) 
                 8% (3/36) 
                  4% (1/22) 
               
               
                   
               
             
          
         
       
     
         [0078]    Based upon the above results, it should be clear that the degree of microbiological contamination for the lumen, and importantly the degree of effluent contamination, is significantly reduced in both the port guide-shielded standard female stopcock port and the stopcock port with port-guide-shielded minimum fluid displacement coupling (clave) attached thereto. This reduction occurs despite relatively high contamination levels on stopcock levers for all stopcocks used in the test. 
         [0079]    In summary, the illustrative port guide effectively reduces the risk of contamination to ports employed on a variety of fluid system components. It is applicable to both standard ports and those employing a clave. It renders the procedure of attaching a syringe or other device easier and allows the practitioner to grasp the region of the port more closely without the risk of contamination to the port lumen/orifice or surrounding locking structure (e.g. threads). It also ensures that the port remains untouched by non-sterile objects during follow-on use between injections/interface with the port. 
         [0080]    The foregoing has been a detailed description of illustrative embodiments of the invention. Various modifications and additions can be made without departing from the spirit and scope of this invention. Each of the various embodiments described above may be combined with other described embodiments in order to provide multiple features. Furthermore, while the foregoing describes a number of separate embodiments of the apparatus and method of the present invention, what has been described herein is merely illustrative of the application of the principles of the present invention. For example, while to port guide is shown as generally cylindrically shaped with a widened aperture and made of plastic/polymer, the port can be of different sizes and cross sectional shapes (e.g. polygonal, ovular, etc.), and constructed of different material (or combinations of materials), such as glass, polycarbonate, steel, resin, plastic, etc. Moreover, while the guide is located around a female port structure, it can be used in conjunction with a male coupling where appropriate or with a genderless coupling. In addition, while the ports are illustratively locking or slip-style luer taper ports, the guide can be adapted for use with other forms of medical fluid couplings such as those receiving needle injections. Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this invention.