Patent Publication Number: US-2018028800-A1

Title: Devices and methods for catheter placement within a vein

Description:
BACKGROUND 
     The embodiments described herein relate generally to fluid transfer medical devices. More particularly, the embodiments described herein relate to devices and methods for placing a catheter within a vein, via an indwelling peripheral intravenous catheter, at a position suitable for blood aspiration. 
     The cutaneous veins of the forearm and hand are the most accessed sites for intravenous catheter insertions and venipunctures for infusing fluid into and/or aspirating bodily fluid from a patient. The standard procedure for blood extraction (i.e. phlebotomy), for example, involves percutaneous insertion of a metal needle (“butterfly needle”) into a patient to gain access to that patient&#39;s vein. The typical hospitalized patient encounters a needle every time a doctor orders a lab test. Repeated needle “sticks” are not only painful and a major source of patient dissatisfaction, but can lead to significantly higher material and labor costs (needles and tubing must be disposed of after every attempt). 
     While most hospitalized patients receive a peripheral intravenous (PIV) catheter that is configured to dwell within a vein for an extended period, PIVs are generally used for infusing fluids and medications rather than blood extraction. In some instances, for example, the failure rates for aspiration reach 20-50% when a PIV has been indwelling (e.g., disposed in a vein) for more than a day. Blood extracted from PIVs is often hemolyzed (i.e., the red blood cells are often ruptured and their contents released), which can result in an unusable sample and a need to repeat the blood collection. 
     Several barriers can contribute to the shortcomings of extracting blood through a PIV. Such barriers can include, for example, catheter malfunctions, occlusion of the vein resulting from the indwelling of the PIV, debris forming around the PIV, collapse of the PIV or vein in response to the negative pressure during aspiration, and/or the like. In addition, the venous anatomy of the forearm and hand have not been well studied or described and, as such, the venous anatomy itself and/or characteristics of blood flow paths therethrough can further present barriers to phlebotomy through an indwelling PIV. 
     Thus, a need exists for improved understanding of the venous anatomy and for devices and methods for placing a catheter within a vein, via an indwelling PIV, at a position suitable for blood aspiration. 
     SUMMARY 
     Devices and methods for placing a catheter within a vein, via an indwelling peripheral intravenous catheter, at a position suitable for blood aspiration are described herein. In some embodiments, an apparatus includes an introducer and a catheter. The introducer has a distal end portion configured to be operatively coupled to an indwelling peripheral intravenous line at least partially disposed in a vein. The catheter is configured to be moved between a first position, in which the catheter is proximal to the peripheral intravenous line when the introducer is operably coupled thereto, and a second position, in which a distal surface of the catheter is distal to the introducer and disposed at a predetermined distance from a distal tip of the peripheral intravenous line. The predetermined distance defined between the distal surface of the catheter and the distal tip of the peripheral intravenous line is based at least in part on a venous anatomy associated with the vein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of a human forearm and human hand showing the vasculature thereof. 
         FIG. 2  is a schematic illustration of a portion of a peripheral intravenous line and a portion of a blood aspiration catheter disposed within a portion of a vein according to an embodiment. 
         FIGS. 3-7  are schematic illustrations of a portion of a peripheral intravenous line and a portion of a blood aspiration catheter disposed within a portion of a vein, each of which having a different anatomic characteristic. 
         FIG. 8  is a perspective view of a fluid transfer device in a first configuration, according to an embodiment. 
         FIGS. 9-11  are each cross-sectional views of the fluid transfer device of  FIG. 8  taken along the line  9 - 9  in the first configuration, a second configuration, and a third configuration, respectively. 
         FIG. 12  is a top view of a fluid transfer device in a first configuration, according to an embodiment. 
         FIGS. 13 and 14  are cross-sectional views of the fluid transfer device of  FIG. 12  taken along the line  13 - 13 , in the first configuration and a second configuration, respectively. 
         FIGS. 15-18  are graphs illustrating data associated with a diameter of a branch vessel in fluid communication with a vein and a distance from a distal surface of a peripheral intravenous catheter disposed in the vein to the branch vessel, according to various embodiments of the peripheral intravenous catheter. 
         FIG. 19  is a graph illustrating data associated with a predicted flow rate (by percentage) within a portion of a vein and a distance from a distal surface of a peripheral intravenous catheter disposed in the vein to a branch vessel in fluid communication with the vein, according to an embodiment. 
         FIG. 20  is a graph illustrating data associated with a predicted flow rate (by percentage) within a portion of a vein and a distance from a distal surface of a peripheral intravenous catheter disposed in the vein to a branch vessel in fluid communication with the vein, according to an embodiment. 
         FIG. 21  is a graph illustrating data associated with a predicted flow rate (by percentage) within a portion of a vein of the hand, a portion of a vein of the forearm, and a portion of the antecubital region and a distance from a distal surface of a peripheral intravenous catheter disposed in the vein to a branch vessel in fluid communication with the vein, according to an embodiment. 
         FIG. 22  is a graph illustrating data associated with a predicted flow rate (by percentage) within a portion of a vein and a distance from an insertion point of a peripheral intravenous catheter into the vein to a branch vessel in fluid communication with the vein, according to an embodiment. 
         FIGS. 23-28  are graphs illustrating data associated with a distance within a vein from a distal surface of a peripheral intravenous catheter to a distal surface of a blood aspiration catheter extending therethrough and predicted success rate associated with placing the distal surface of the blood aspiration catheter in a portion of the vein having a desired set of characteristics, according to various embodiments. 
         FIG. 29  is a flowchart illustrating a method of using a fluid transfer device to place a catheter within a vein, via an indwelling peripheral intravenous catheter, at a position suitable for blood aspiration, according to an embodiment. 
         FIGS. 30-43  illustrate various aesthetic and/or industrial designs of a fluid transfer device each according to a different embodiment. 
         FIGS. 44 and 45  are various views of a locking mechanism configured for use with a fluid transfer device each according to a different embodiment. 
         FIGS. 46-61  illustrate various fluid transfer devices each with a different color and/or labeling scheme according to particular embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In some embodiments, an apparatus includes an introducer and a catheter. The introducer has a distal end portion configured to be operatively coupled to an indwelling peripheral intravenous line at least partially disposed in a vein. The catheter is configured to be moved between a first position, in which the catheter is proximal to the peripheral intravenous line when the introducer is operably coupled thereto, and a second position, in which a distal surface of the catheter is distal to the introducer and disposed at a predetermined distance from a distal tip of the peripheral intravenous line. The predetermined distance defined between the distal surface of the catheter and the distal tip of the peripheral intravenous line is based at least in part on a venous anatomy associated with the vein. 
     In some embodiments, an apparatus includes an introducer, a catheter, and an actuator. The introducer defines a lumen. A distal end portion of the introducer is configured to be operably coupled to an indwelling peripheral intravenous line at least partially disposed in a vein. The catheter has a proximal end portion and a distal end portion and defines a lumen extending through the proximal end portion of the catheter and the distal end portion of the catheter. At least a portion of the catheter is movably disposed in the lumen of the introducer. The actuator is movably coupled to the introducer. A portion of the actuator is disposed in the lumen and coupled to the proximal end portion of the catheter. The actuator is configured to be moved relative to the introducer to move the catheter between a first position, in which the catheter is proximal to the indwelling peripheral intravenous line when the introducer is operably coupled thereto, and a second position, in which a distal surface of the catheter is distal to the indwelling peripheral intravenous line and within the vein such that at least one of a valve of the vein or a branch vessel in fluid communication with the vein is disposed between a distal tip of the indwelling peripheral intravenous line and the distal surface of the catheter. 
     In some embodiments, a method includes coupling a fluid transfer device to an indwelling peripheral intravenous line at least partially disposed in a vein of a patient. The fluid transfer device includes at least a catheter configured to be moved relative to the indwelling peripheral intravenous line. The catheter is moved from a first position, in which the catheter is proximal to the indwelling peripheral intravenous line, to a second position, in which at least a portion of the catheter is disposed within the indwelling peripheral intravenous line such that a distal surface of the catheter is disposed at a predetermined distance from a distal tip of the indwelling peripheral intravenous line. The predetermined distance is based at least in part on a venous anatomy associated with the vein. A volume of blood is transferred via the catheter from the vein to a fluid reservoir in fluid communication with the catheter. The catheter is moved from the second position toward the first position after transferring a desired volume of blood to the fluid reservoir. The fluid transfer device is then decoupled from the indwelling peripheral intravenous line after moving the catheter from the second position toward the first position. 
     As used in this specification, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, the term “a member” is intended to mean a single member or a combination of members, “a material” is intended to mean one or more materials, or a combination thereof. 
     As used herein, the terms “about” and “approximately” generally mean plus or minus 10% of the value stated. For example, about 0.5 would include 0.45 and 0.55, about 10 would include 9 to 11, about 1000 would include 900 to 1100. 
     As used herein, the terms “catheter” and “cannula” are used interchangeably to describe an element configured to define a passageway for moving a bodily fluid from a first location to a second location (e.g., a fluid passageway to move a bodily fluid out of the body). While cannulas and/or catheters can receive a trocar, a guide wire, or an introducer to deliver the cannula and/or catheter to a volume inside the body of a patient, the cannulas and/or catheters referred to herein need not include or receive a trocar, guide wire, or introducer. Similarly, the terms “peripheral intravenous catheter” and “peripheral intravenous line” are used interchangeably to describe a device configured to percutaneously access a vein via venipuncture. 
     As used herein, the term “indwelling” when characterizing a catheter or the like generally refers to a catheter that is at least partially disposed within a portion of the body. For example, an “indwelling peripheral intravenous catheter” (also referred to as “indwelling peripheral intravenous line,” “PIV catheter,” “PIV line,” or “PIV”) can be a peripheral intravenous catheter that is percutaneously inserted into the body and at least partially disposed within a vein. In general, the methods of using the devices and/or embodiments described herein include gaining access to a vein of a patient via an indwelling peripheral intravenous catheter. In other words, the methods and/or embodiments described herein involve gaining access to a vein of a patient via a peripheral intravenous catheter previously inserted through the skin of the patient and partially disposed within the vein. 
     As used herein, the words “proximal” and “distal” when used in the context of a device refer to the direction closer to and away from, respectively, a user who would place the device into contact with a patient. Thus, for example, an end of the device first touching the body of the patient would be a distal end of the device, while an opposite end of the device (e.g., the end of the device being manipulated by the user) would be a proximal end of the device. The terms “proximal” and “distal” when used to describe a portion of the body refer to positions and/or directions closer to and away from, respectively, a central portion of the body. Thus, for example, a patient&#39;s hand is distal to the patient&#39;s forearm. 
     In some instances, the words “proximal” or “distal” can be relative terms and do not necessarily refer to universally fixed positions or directions. For example, a distal end portion of a peripheral intravenous (PIV) catheter is configured to be inserted into a vein of a patient&#39;s forearm while a proximal end portion of the PIV catheter can be substantially outside of the body. Veins, however, carry a flow of oxygen-poor blood from distal portions of the body back to the heart and, as a result, PIV catheters are generally inserted into a vein such that a distal tip of the PIV catheter is disposed within the vein in a position proximal to the insertion point (e.g., extending relative to the vein in a proximal direction). Thus, a distal position relative to the PIV catheter can refer to, for example, a proximal position relative to the vein (e.g., closer to the heart). 
     The devices and methods described herein can be used to advance a blood draw catheter at least partially through, for example, an indwelling PIV to place a distal end of the blood draw catheter in a desired position relative to a vein and/or the PIV. As used herein, the terms “predetermined distance” and “desired distance” generally refer to a distance defined between a distal end of a blood draw catheter and a distal end of a PIV in which the blood draw catheter is at least partially disposed. When describing a “predetermined distance” and/or a “desired distance” defined between the distal end of the catheter and the distal end of the IV, it should be understood that such a distance is within, for example, an acceptable range of predetermined distances. For example, an acceptable range of predetermined distances can be between, for example, 0.0 millimeters (mm) and about 50.0 mm. Thus, in some instances, a predetermined distance between a distal end of a first catheter and a distal end of a first PIV can be about 15.0 mm while in other instances, a predetermined distance between a distal end of a second catheter and a distal end of a second PIV can be above 30.0 mm. Furthermore, a predetermined distance can refer to a positive distance in which a distal end of a catheter is distal to a distal end of a PIV or a negative distance in which a distal end of a catheter is proximal to a distal end of a PIV. 
     The devices and methods described herein generally relate to the aspiration of blood from a vein of a patient, which is accessed via an indwelling peripheral intravenous (PIV) catheter. The cutaneous veins of the antecubital arm region, forearm, and hand are the most accessed sites for intravenous catheterization. For reference,  FIG. 1  is illustrates a human forearm  10  and human hand  30  showing the vascular system thereof. While specific vascular structures are identified, it is to be understood that the proceeding identified regions do not constitute the entire vascular system of the forearm and/or hand; rather, the regions of the forearm  10  and the hand  30  are presented in  FIG. 1  as a simplified example suitable for the discussion of the embodiments and methods herein. Moreover, it is to be understood that the vasculature represented in  FIG. 1  is but one example and that while serving substantially the same function, the arrangement of an individual&#39;s vascular system in the forearm and hand can vary from what is shown in  FIG. 1 . 
     The venous system of the forearm  10  includes a basilic vein  11  and a cephalic vein  12 , each of which extend distally to the hand  30 . The basilic vein  11  and the cephalic vein each provide a flow of oxygen-depleted blood from distal portions of the hand  30  and forearm  10  to the vascular system of the upper arm (i.e., the subclavian vein, not shown). A median cubital vein  13  branches from the basilic vein  11  and establishes fluid communication between the basilic vein  11  and a median vein  15  as well as fluid communication between the basilic vein  11  and a median cephalic vein  16 . Similarly, an accessory cephalic vein  14  joins the median cubital vein  13  to establish fluid communication between the cephalic vein  12  and the median cephalic vein  16 . The median vein  15  and the median cephalic vein  16  branch collectively to form perforating or anastomotic veins  17 . The basilic vein  11  and the cephalic vein  12  are each in fluid communication with the metacarpal veins  31  of the hand  30 , which in turn, are in fluid communication with the dorsal digital veins  32 . As shown in  FIG. 1 , the forearm  10  and the hand  30  can also include any number of veins and/or branches that combine or divide the veins into a fewer number of veins or a greater number of veins, respectively. 
     The arterial system of the forearm  10  includes a brachial artery  21  and an ulnar artery  22 , each of which extend distally to the hand  30 . The brachial artery  21  and the ulnar artery  22  each provide a fluid of oxygen-rich blood from the vascular system of the upper arm (i.e., the subclavian artery, not shown) to the distal portions of the forearm  10  and hand  30 . The brachial artery  21  branches into a median artery  23  and a radial artery  24 . The radial artery  24 , in turn, branches into a metacarpal artery branch  25 . The ulnar artery  22  and the metacarpal artery branch  25  supply oxygen-rich blood to the hand  30 . As shown in  FIG. 1 , the forearm  10  and the hand  30  can also include any number of arteries and/or branches that combine or divide the arteries into a fewer number of arteries or a greater number of arteries, respectively. 
       FIG. 2  is a schematic illustration of a blood draw catheter  160  and a peripheral intravenous catheter  180  partially disposed within a vein  40  according to an embodiment. The vein  40  can be any suitable vein such as those included in the forearm or hand of a patient as described above with reference to  FIG. 1 . As shown, the vein  40  defines a lumen that includes a set of valves V 1 , V 2 , and V 3 . The vein  40  is in fluid communication with a set of branch vessels (veins) B 1 , B 2 , B 3 . While the vein  40  is particularly shown in  FIG. 2 , it should be understood that the arrangement of the vein  40  is presented by way of example and not limitation. Specifically, while the valves V 1 , V 2 , and V 3 , and the branch vessels B 1 , B 2 , B 3  (also referred to herein as “branches”) are shown in a particular arrangement relative to the vein  40 , the arrangement illustrated in  FIG. 2  is intended to present a general schematic of known anatomic structures of the vascular system. While the vascular structures are schematically presented with reference to  FIG. 2 , specific characterizations and/or data associated with these structures—at least as it relates to blood draw via catheterization through a peripheral intravenous catheter dwelling therein—is/are described in further detail hereinbelow. 
     The valves V 1 , V 2 , and V 3  (referred to collectively as “valves V”) disposed within the lumen of the vein  40  substantially control the flow of blood through the lumen. Any of the valves V, for example, can transition from a closed configuration to an open configuration to allow a selective flow of blood therethrough. When referring to the valve(s) V and/or any other valve(s) described herein it should be understood that the valve(s) can be anatomic structures within the vein or can be any other suitable form of flow control serving a function similar to anatomical valves and/or acting in a valve-like manner to obstruct and/or control blood flow in one or more directions. For example, a vein can include any number of anatomical valves formed of tissue and disposed in a given position within the vein. Such a valve(s) typically control a flow of blood within the vein in a single direction (e.g., in a proximal direction or in a direction toward the heart). In other words, valves generally limit and/or substantially prevent a backflow of blood within the vein (e.g., in a distal direction or in a direction away from the heart). 
     In other instances, however, an event can trigger or otherwise can result in a valve-like response within a portion of the vein that can selectively control a flow of blood through that portion. For example, in some instances, a vasospasm of a portion of the vein can result in a constriction of a lumen defined by the portion of the vein sufficient to restrict and/or otherwise limit a flow of blood therethrough (e.g., in a proximal and/or a distal direction). In such instances, a relaxing of the portion of the vein after the vasospasm can result in a dilation of the vein and/or otherwise a return to a non-spastic arrangement, which in turn, removes the limitation on the blood flow resulting from the vasospasm. As such, the occurrence of a vasospasm along a portion of a vein can effectively result in a valve-like response (albeit in a proximal and/or distal direction) within that portion of the vein sufficient to selectively control (e.g., limit or obstruct) a flow of blood therethrough. In some instances, the presence of a catheter within the vein and/or a contact between a portion of the catheter and a portion of the vein wall can result in a vasospasm of at least a portion of the vein. In other instances, a vein, debris (e.g., thrombus), muscle response, constriction, and/or any other structure, event, and/or response can act in a valve-like function within the vein and/or can otherwise restrict a flow of blood through the vein (e.g., in a proximal and/or distal direction within the vein). By way of example, the flexing of a muscle, the bending of a joint or appendage (e.g., elbow, arm, fingers, etc.), the presence of an externally applied force (e.g., pressure applied by a blood pressure cuff, pressure applied by a medical professional&#39;s hand or finger(s), pressure applied by an ultrasound probe), coughing or valsalva resulting in a temporary reversal of blood flow, injection of substances resulting in vaso-inflammation, and/or the like. Thus, the devices and methods described herein can be configured and/or used to insert a blood draw catheter (e.g., the blood draw catheter  160 ) into a vein (e.g., the vein  40 ) and to advance the blood draw catheter to a position within the vein that is beyond and/or through any of the flow restrictions described above, thereby placing the blood draw catheter in a position within the vein that receives a substantially unrestricted flow of blood, as described in further detail herein. 
     In some instances, one or more of the valves V can transition between an open or closed configuration to, for example, divert a flow of blood through a branch or the like. In some instances, compartments defined between two adjacent valves in the closed configuration can result in a significantly reduced flow of blood through that compartment. In some instances, a flow of blood can enter and/or exit a compartment defined by adjacent closed valves via one or more branch vessels. The vascular system of a person can include multiple veins that can branch from the vein  40  and/or join the vein  40 , thereby forming a bypass or the like that can define a flow path within which blood can flow around occlusions of the vein  40  (see e.g.,  FIG. 1 ). 
     The flow characteristics associated with the vein  40  are based at least in part on the arrangement of the vascular structure thereof and/or in fluid communication therewith. For example, as shown in  FIG. 2 , the vein  40  has a diameter D 1  and each of the branches B 1 , B 2 , and B 3  (collectively referred to as “branches B”) has a diameter D 2 . In some instances, the volumetric flow rate of blood through the vein  40  can be based at least in part on the diameter D 1  of the vein  40 . Similarly, the volumetric flow rate of blood through the vein  40  can be based on the diameter D 2  of the branches B, in which branches with a smaller diameter deliver a smaller volume of blood to the vein  40  and branches with a larger diameter deliver a larger volume of blood to the vein. Thus, when the branches B in fluid communication with the vein  40  have a larger diameter D 2 , the volumetric flow rate through the vein  40  is greater than when the branches B have a smaller diameter. Although the branches B 1 , B 2 , and B 3  are shown in  FIG. 2  as having the same diameter, it should be understood that the diameter of each branches B 1 , B 2 , or B 3  can vary. As such, the vein  40  and/or compartments of the vein  40  defined between adjacent valves V can have localized areas of higher or lower volumetric flow rates. 
     As described above, a portion of the peripheral intravenous catheter  180  and a portion of the blood draw catheter  160  are disposed in the lumen of the vein  40 . The peripheral intravenous catheter  180  (also referred to herein as “peripheral intravenous line” or simply “PIV”) can be any suitable peripheral intravenous catheter such as any suitable known PIV. The PIV  180  can have any suitable length between a hub (not shown) and a distal surface of the PIV catheter. For example, the length can be between about 19 millimeters (mm) (about 0.75 inches (in)) and about 45 mm (about 1.75 in). Similarly, the PIV  180  can have any suitable diameter D 3 . For example, the diameter D 3  can be between about 26-gauge (or about 0.45 mm) and about 14-gauge (or about 2.0 mm). In some of the embodiments described herein, the PIV  180  can be a Jelco® 1.0 in, 20-gauge catheter manufactured by Smiths Medical, St. Paul, Minn., USA (referred to herein as “Jelco® 1.0 in, 20-gauge catheter” or “Jelco® 1.0 in, 20-gauge PIV”). 
     In use, the size of the PIV  180  is generally based, at least in part, on a size of the vein in which the PIV  180  will be disposed. For example, in some instances, the PIV  180  is inserted into a portion of the basilic vein  11  of the forearm  10  (see  FIG. 1 ). In some such instances, a diameter of the portion of the basilic vein  11  (e.g., the diameter D 1  of the vein  40 ) can be sufficiently large to use, for example, a 20-gauge PIV (e.g., the diameter D 3  of the PIV  180 ). In other instances, such as when the PIV  180  is inserted into a portion of a vein of the hand (e.g., the metacarpal vein  31  of the hand  30  in  FIG. 1 ), the diameter of the vein (e.g., the diameter D 1  of the vein  40 ) can preclude the use of a PIV with a diameter larger than, for example, 26-gauge or 24-gauge. 
     In some instances, the positioning of the portion of the PIV  180  within the vein  40  results in at least a partial occlusion of the lumen of the vein  40 . That is to say, the presence of the PIV  180  within the vein reduces and/or restricts a flow of blood around the PIV  180 . For example, as shown in  FIG. 2 , the PIV  180  can be inserted into the vein  40  such that a distal end portion is disposed in a compartment defined between the valve V 1  (e.g., a proximal valve) and the valve V 2  (e.g., a distal valve), which in turn, receives a limited flow of blood due to the presence of the PIV  180 . In some instances, the distal surface of the PIV  180  (also referred to as the “distal tip”) can be distal to the branch B 1  and spaced apart from the branch B 1  by a distance or length L 1 . In other instances, the distal surface of the PIV  180  can be proximal to the branch B 1 . In some instances, the flow of blood through the compartment can be reduced despite the compartment receiving a flow of blood from the branch B 1  ( FIG. 2 ) and/or regardless of the position of the distal surface of the PIV  180  relative to the branch B 1 . In some instances, the flow of blood into the compartment can be reduced by about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or about 99%. In other instances, the presence of the PIV  180  can restrict the flow of blood through the compartment by 100%. In still other instances, the presence of the PIV  180  can restrict the flow of blood through the compartment by less than 10%. 
     In general, peripheral intravenous catheters such as the PIV  180  are used to infuse fluids into the body and are not used to aspirate blood because of, for example, low blood return levels, debris surrounding the distal tip of the PIV, kinks in the PIV, hemolysis of blood samples, vein collapse, and/or the like. As shown in  FIG. 2 , however, the blood draw catheter  160  (also referred to herein as “catheter”) can be inserted through a lumen defined by the PIV  180  and used to aspirate blood. The catheter  160  can be any suitable size that is based at least in part on the size of the PIV  180 . For example, the catheter  160  can have a diameter that is smaller than an inner diameter of the PIV  180 , thereby allowing the catheter  160  to be inserted therethrough. 
     The catheter  160  can be positioned at a predetermined distance or length L 2  from the distal surface of the PIV  180 . As described in further detail herein, the distance or length L 2  between the distal tip of the PIV  180  and a distal surface of the catheter  160  can be based at least in part on information associated with the vascular structure of the vein  40  (e.g., number and position of valves, number and position of branches, diameter of the vein  40  or branches B, etc.). In some instances, the length L 2  can be sufficient to dispose the distal surface of the catheter  160  in a compartment defined between the valve V 2  and the valve V 3 . That is to say, the distal surface of the catheter  160  can be disposed in a compartment of the vein  40  that is distal to the compartment in which the distal tip of the PIV  180  is disposed, as shown in  FIG. 2 . In some instances, the distal surface of the catheter  160  can be disposed in a position within the vein  40  having a volumetric flow rate that is greater than a volumetric flow rate through the compartment in which the distal tip of the PIV  180  is disposed. In this manner, the catheter  160  can be used to aspirate a volume of blood. 
     In some instances, the distal surface of the catheter  160  can be disposed at a distance or length L 3  from the branch B 3 , as shown in  FIG. 2 . In some instances, the distance or length L 3  can be a “buffer zone” or the like. As described in further detail herein, in some instances, it may be desired to reduce the distance or length L 3  of the buffer zone to increase a likelihood of a successful blood draw through the catheter  160 . In other instances, the distance of length L 3  of the buffer zone may not substantially impact the likelihood of a successful blood draw. Similarly, while the distal surface of the catheter  160  is shown in  FIG. 2  as being proximal to the valve V 3  in other instances the catheter  160  can be positioned such that the distal surface of the catheter  160  is distal to the valve V 3 . Thus, the placement of the catheter  160  within the vein  40  and relative to the PIV  180  can increase or decrease a likelihood of successful blood draw therethrough, as described in further detail herein. In some instances, for example, it can be desirable to position the distal surface of the catheter  160  between about 1.0 in and about 1.25 in from the distal tip of the PIV  180 , as described in further detail herein. 
     While the vein  40  is shown in  FIG. 2  as having a number of valves V and branches B, a catheter can be inserted through a peripheral intravenous line at least partially dwelling in a vein having any suitable anatomical features and/or structures. In general, the vascular structures of a person vary, at least slightly, from the vascular structures of other people. The varying vascular structures, in some instances, can impact the size, shape, arrangement, and/or efficacy of blood aspiration via a PIV and/or via standard phlebotomy methods. Thus, as described in further detail herein, determining characteristics of vascular structures and providing devices having a configuration based at least in part on the characteristics of the vascular structures, in some instances, can result in an increased success rate associated with blood aspiration in general, and more specifically, with blood aspiration through an indwelling PIV. 
       FIGS. 3-6  are schematic illustrations of a blood draw catheter  260  and a peripheral intravenous catheter  280  partially disposed within a vein  40  according to an embodiment. The blood draw catheter  260  (also referred to herein as “catheter”) and the peripheral intravenous catheter  280  (also referred to herein as “peripheral intravenous line” or simply “PIV”) can be any suitable catheter device or devices. For example, in some embodiments, the catheter  260  and the PIV  280  can be substantially similar to the catheter  160  and the PIV  180 , respectively, described above with reference to  FIG. 2 . In some embodiments, the catheter  260  can be included in a fluid transfer device such as those described in further detail herein. In some embodiments, the PIV  280  can be, for example, a standard, commercially available peripheral intravenous catheter such as a Jelco® 1.0 inch, 20-gauge catheter (as described above with reference to the PIV  180 ). As such, the catheter  160  and the PIV  180  are not described in further detail herein. 
     As shown in  FIG. 3 , in some instances, the PIV  280  can be inserted into and/or can be otherwise dwelling within a vein  40  having a branch vessel B in fluid communication with the vein  40  and a valve V formed proximally (e.g., downstream) of the branch vessel B. That is to say, the arrangement of the catheter  260 , PIV  280 , and vein  40  is such that the branch vessel B is between a distal end portion of the catheter  260  and the valve V. In some instances, the presence of the PIV  280  and/or catheter  260  within the vein  40  can result in a blockage and/or occlusion of the vein  40  distal to the PIV insertion point, which in some instances, can result in an at least partial reduction in volumetric flow rate of the blood therethrough. In some instances, the branch vessel B (also referred to as “branch”) can provide an inlet flow of blood into the vein  40 . Thus, in this arrangement, the distal end of the catheter  260  can be disposed in a portion of the vein  40  receiving a flow of blood from the branch B that is sufficient for blood aspiration through the catheter  260 . 
     While the flow of blood through the branch B is generally an inlet flow of blood (e.g., a flow of blood from a distal position to a proximal position of the branch and/or vein  40  and/or otherwise in the direction of the heart), in some instances, the branch vessel B can receive an outlet flow of blood from the vein  40 . In some such instances, a negative pressure resulting from aspiration through the catheter  260  can be sufficient to draw a volume of blood into the catheter  260  despite the outlet flow of blood from the vein  40  to the branch B. In other instances, the outlet arrangement of the branch B can result in a portion and/or compartment of the vein  40  being unsuitable for aspiration. In such instances, a nurse, technician, phlebotomist, doctor, etc. can move the catheter  260  (e.g., relative to the PIV  280  and the vein  40 ) to place the distal tip of the catheter  260  in a different portion and/or compartment of the vein  40  that is otherwise suitable for aspiration. Thus, relocating the catheter  260  relative to the PIV  280  can place the catheter  260  in fluid communication with a portion of the vein  40  receiving a flow of blood sufficient for aspiration through the catheter  260  while maintaining access to the vein  40  via the indwelling PIV  280 . In other words, the catheter  260  can be relocated without performing a venipuncture otherwise used to access the vein  40 . 
     In some instances, the reduction in blood flow past the PIV  280  resulting from the at least partial occlusion of the vein  40  can be such that the success of aspirating a volume of blood is at least partially dependent on the flow of blood from or through the branch B. That is to say, in some instances, the absence of the branch B can otherwise result in a volumetric flow rate within the portion of the vein that is insufficient for blood aspiration through the catheter  260 . For example,  FIG. 4  illustrates the PIV  280  and the catheter  260  dwelling within a vein  40  having a valve V disposed between a distal tip of the catheter  260  and a branch vessel B. In some instances, a volumetric flow rate associated with a compartment of the vein  40  defined between, for example, a PIV insertion site and the valve V (e.g., in which the distal tip of the catheter  260  is disposed) can be insufficient for blood aspiration through the catheter  260 . In other instances, the catheter  260  can be advanced relative to the PIV  280  such that at least the distal tip of the catheter  260  extends through the valve V, thereby placing the catheter  260  in fluid communication with a flow of blood, for example, from the branch B. As described above, the relocation of the catheter  260  relative to the PIV  280  can place the catheter  260  in fluid communication with a portion of the vein  40  receiving a flow of blood sufficient for aspiration through the catheter  260  while maintaining access to the vein  40  via the indwelling PIV  280 . 
     In some instances, the reduction in blood flow past the PIV  280  resulting from the at least partial occlusion of the vein  40  can be such that the success of aspirating a volume of blood is not dependent on the flow of blood from or through the branch B. For example,  FIG. 5  illustrates the PIV  280  and the catheter  260  dwelling within a vein  40  having a diameter that is sufficiently large to allow blood to flow around the portion of the PIV  280  and/or catheter  260  dwelling in the vein  40 . In some such instances, the vein  40  is not in fluid communication with a branch vessel that is between the catheter  260  and the valve V, yet a volumetric flow rate through that portion of the vein  40  is nonetheless sufficient for aspiration through the catheter  260 . Moreover, in some such instances, because a sufficient volume of blood flows past the PIV  280 , the location of the distal end of the catheter  260  relative to a distal end of the PIV  280  can be variable. That is to say, in such instances, the catheter  260  placement is not dependent on a position of a branch vessel and/or a valve V. In some instances, for example, the distal tip of the catheter  260  and the distal tip of the PIV  280  can be flush. In other instances, the catheter  260  can remain within a portion of the PIV  280  (e.g., the distal tip of the catheter  260  is proximal to the distal tip of the PIV  280 , relative to the user). 
     Conversely, in other instances, the PIV  280  and the catheter  260  can be dwelling within a vein  40  having a relatively small diameter, as shown in  FIG. 6 . In such instances, the PIV  280  can substantially block or occlude the lumen of the vein  40  such that little or no flow of blood flows past the PIV  280 . In such instances, a portion of the vein  40  may also lack a branch vessel and/or valve. As such, a negative pressure exerted through the catheter  260  for aspiration, in some instances, can be sufficient to collapse a portion of the vein  40 . For example, the negative pressure exerted through the catheter  260  can result in at least a portion of the vein wall collapsing, which in turn, can at least partially occlude an opening of the catheter  260 , as illustrated by the arrow AA in  FIG. 7 . In some instances, modulating a pressure and/or a rate of pressure change can limit and/or reduce a likelihood of vein collapse. Similarly, the catheter  260  and/or any suitable portion of a fluid transfer device coupled to the catheter  260  can be configured to limit, modulate, cap, and/or control a negative pressure exerted therethrough and/or can have a diameter or design configured to limit a volumetric flow rate therethrough, which in turn, can limit and/or reduce a likelihood of vein collapse. 
     In some instances, the catheter  260  can be moved relative to the PIV  280 , for example, to place the distal end of the catheter  260  in a position within the vein  40  having a larger diameter and/or that is otherwise able to resist collapse. For example, the position within the vein  40  can be proximal to a branch vessel or valve. In other instances, the catheter  260  can be removed from the PIV  280  and can be replaced with, for example, a catheter having a smaller gauge or the like, which in turn, can result in a decrease in negative pressure associated with aspiration. In some instances, after a vein collapse (e.g., as shown in  FIG. 7 ), the catheter  260  can be advanced within the vein  40  to move the catheter  260  through the collapsed portion, thereby disposing the opening of the catheter  260  in a non-collapsed portion of the vein  40 . As described above, the relocation and/or replacement of the catheter  260  relative to the PIV  280  can allow for aspiration through the catheter  260  while maintaining access to the vein  40  via the indwelling PIV  280 . 
     In some instances, any suitable fluid transfer device can be used to insert a catheter though an indwelling PIV to draw a volume of blood from a patient. For example,  FIGS. 8-11  illustrate a fluid transfer device  300  used for phlebotomy through a peripheral intravenous line. The fluid transfer device  300  includes an introducer  310 , a catheter  360 , an actuator  370 , and an adapter  375 . The fluid transfer device  300  can be any suitable shape, size, or configuration and is configured to be coupled to, for example, a peripheral intravenous line (NV). In some embodiments, the fluid transfer device  300  can be similar to and/or substantially the same as any of those described in U.S. Patent Publication No. 2014/0364766 entitled, “Systems and Methods for Phlebotomy Through a Peripheral IV Catheter,” filed Aug. 26, 2014 (referred to henceforth as the “&#39;766 publication”), the disclosure of which is incorporated herein by reference in its entirety. As such, portions of the fluid transfer device  300  (also referred to herein as “transfer device” or “device”) are not described in further detail herein. 
     As described above, the transfer device  300  includes the introducer  310 , the catheter  360 , the actuator  370 , and the adapter  375 . The adapter  375  can be any suitable adapter such as, for example, a Y-adapter or a T-adapter. For example, in this embodiment, the adapter  375  is a T-adapter including a first port coupled to the introducer  310 , a second port coupled to a cannula (see e.g.,  FIG. 8 ), and a third port that can be coupled to the PIV (not shown). In some embodiments, the ports can be and/or can include a Luer Lok™ or the like that can fluidically seal the ports when the adapter  375  is not coupled to a device (e.g., the transfer device  300 , a PIV, etc.). 
     The introducer  310  of the transfer device  300  includes a first member  311  and a second member  313 . The introducer  310  can be any suitable shape, size, or configuration. For example, in some embodiments, the introducer  310  can be disposed in and/or can have a substantially telescopic arrangement (as shown in  FIGS. 9-11 ). In some embodiments, the introducer  310  can have a shape that is, for example, similar to a syringe or the like. The first member  311  includes a proximal end portion and a distal end portion. The proximal end portion of the first member  311  is configured to be engaged by a user during operation (e.g., the proximal end portion includes a flange or the like). The distal end portion of the first member  311  includes and/or is otherwise coupled to a lock  350 . For example, the lock  350  can be a Luer Lok™ or the like configured to couple the introducer  310  to the adapter  375  and/or an indwelling PIV (not shown in  FIGS. 8-11 ). Moreover, the lock  350  includes a seal member  320  that defines and/or forms a substantially fluid tight seal with, for example, the first member  311 . In addition, the seal member  320  receives a portion of the second member  313  and/or the catheter  360  as the second member  313  and/or the catheter  360  is advanced beyond the seal member  320  in the distal direction and maintains a substantially fluid tight seal around the portion of the second member  313  and/or the catheter  360 , thereby substantially preventing a backflow of fluid into the introducer  310 . The seal member  320  can be any suitable configuration such as, for example, an O-ring, a one-way valve, a diaphragm, a self-healing diaphragm, a check valve, or any other suitable seal member. 
     The first member  311  slidably receives at least a portion of the second member  313  and/or the actuator  370 . The first member  311  defines a channel  312  that is configured to define a range of motion for the second member  313  relative to the first member  311 . The channel  312  extends along a length of the first member  311  between the proximal end portion  3151  and the distal end portion  3152 , as shown in  FIGS. 9-11 . More particularly, the channel  312  does not extend through the proximal end portion and/or the distal end portion of the first member  311  (i.e., the channel  312  does not extend the entire length of the first member  311 ). Thus, at least a distal end portion the channel  312  is bounded by an inner surface of the first member  311 . The channel  312  can have any suitable shape and/or size. For example, in some embodiments, the channel  312  has a first cross-sectional area at or near the proximal end portion of the first member  311  and a second cross-sectional area at or near a distal end portion of the first member  311 . In some embodiments, the channel  312  can be configured to fan-out, flare, and/or otherwise widen along a length of the first member  311  in the distal direction. As described in further detail herein, a portion of the second member  313  can be movably disposed in the channel  312 , which in turn, defines, for example, a range of motion associated with the second member  313  relative to the first member  311 . 
     The second member  313  of the introducer  310  includes a proximal end portion and a distal end portion. The distal end portion of the second member  313  has a protrusion  314  extending from an outer surface that is movably disposed within the channel  312  of the first member  311 . The distal end portion of the second member  313  includes and/or is coupled to a guide member  330  that receives at least a portion of the catheter  360 . The guide member  330  is configured to support and/or otherwise guide at least the portion of the catheter  360  as the catheter  360  is advanced through the introducer  310 . For example, in some embodiments, the guide member  330  can be formed from a metal or hard plastic (e.g., with a higher durometer that the catheter  360 ), which can allow the guide member  330  to advance through the introducer  310 , a PIV (not shown), and/or any obstruction or kink included therein. Moreover, the second member  313  can include a seal member  315  disposed in a distal position within an inner volume of the second member  313  and about a portion of the guide member  330 . The seal member  315  forms a substantially fluid tight and/or substantially hermetic seal about the guide member  330 . In some embodiments, the seal member  315  can be formed from an absorbent material such as POREX® or the like. 
     The arrangement of the introducer  310  is such that when the second member  313  is moved relative to the first member  311 , the protrusion  314  is moved within the channel  312 . As such, the channel  312  (and/or the portion of the inner surface defining the channel  312 ) defines a range of motion for the second member  313  relative to the first member  311 . For example, with the channel  312  extending along the length of the first member  311 , the range of motion associated with the second member  313  as defined by the channel  312  includes an axial motion (e.g., a distal and/or proximal direction) of the second member  313  within the first member  311  between its proximal position and its distal position. Similarly, the increased width associated with the second cross-sectional area can define, for example, a rotational range of motion about a longitudinal centerline of the first member  311 , thereby allowing the second member  313  to at least partially rotate within and/or relative to the first member  311  (as described in detail in the &#39;766 publication). 
     As shown in  FIGS. 8-11 , the actuator  370  of the transfer device  300  includes a proximal end portion and a distal end portion. In some instances, a user can engage the proximal end portion to manipulate at least the actuator  370  of the transfer device  300  to transition the transfer device  300  between, for example, a first configuration ( FIGS. 8 and 9 ), a second configuration ( FIG. 10 ), and a third configuration ( FIG. 11 ). The proximal end portion is coupled to a secondary catheter  378  that includes a coupler  379 , which in turn, can be coupled to a fluid reservoir (e.g., an evacuated container, sample reservoir, syringe, etc.). As described in further detail herein, the actuator  370  couples to the catheter  360  and places a lumen of the catheter  360  in fluid communication with a lumen of the secondary catheter  378 . Thus, when the coupler  379  is coupled to the fluid reservoir, the catheter  360  is placed in fluid communication with the fluid reservoir. 
     The actuator  370  can have any suitable shape, size, or configuration. At least a portion of the actuator  370  can be inserted into the second member  313  and can be moved between, for example, a proximal position and a distal position (e.g., in a telescopic motion). In some embodiments, the actuator  370  can define a slot or the like configured to receive a portion of the second member  313 . In such embodiments, a length of the slot can define a range of motion of the actuator  370  relative to the second member  313 . 
     The catheter  360  of the transfer device  300  can be any suitable shape, size, or configuration. For example, in some embodiments, the catheter  360  can be about a 20-gauge catheter or the like. In other embodiments, the catheter  360  can be greater than or less than a 20-gauge catheter. Moreover, the catheter  360  can be formed of any suitable biocompatible material having any suitable stiffness and/or Shore durometer such that the catheter  360  has a desired flexibility, which in turn, can allow the catheter  360  to elastically deform without, for example, kinking or the like. 
     The catheter  360  has a proximal end portion and a distal end portion. The proximal end portion of the catheter  360  is coupled to the actuator  370  such that the lumen defined by the catheter  360  is in fluid communication with the secondary catheter  378 . The distal end portion of the catheter  360  can be arranged in any suitable manner. For example, in some embodiments, the distal end portion of the catheter  360  can include a substantially open end-surface configured to place the lumen  3209  in fluid communication with, for example, a vein. In some embodiments, the distal end portion can include the open end-surface and any number of openings disposed on the side (e.g., circumference) of the catheter  360 , as described in the &#39;766 publication. 
     As shown in  FIGS. 8 and 9 , prior to use, the transfer device  300  can be disposed in a first configuration (e.g., an expanded configuration), in which the second member  313  is disposed in a proximal position relative to the first member  311  and the actuator  370  is disposed in a proximal position relative to the second member  313 . In this manner, the guide member  330  is disposed within the first member  311  of the introducer  310  and at least the distal end portion of the catheter  360  is disposed within the guide member  330 . Said another way, the catheter  360  is at least partially disposed in the introducer  310  when the transfer device  300  is in the first configuration. In some embodiments, the inner volume of the second member  313  and the inner volume of the first member can be substantially fluidically sealed such that the inner volumes are each substantially sterile. As a result, at least a portion of the catheter  360  is maintained in a substantially sterile environment prior to use. 
     While in the first configuration, a user (e.g., a phlebotomist) can manipulate the transfer device  300  to couple the first member  311  of the introducer  310  to the adapter  375 . In other embodiments, the transfer device  300  can be pre-assembled with the adapter  375 . In still other embodiments, the transfer device  300  can be used without the adapter  375 . Although not shown in  FIGS. 8-11 , the third port of the adapter  375  can be coupled to a PIV. As a result, the introducer  310  is coupled (e.g., indirectly via the adapter  375  or directly when used without the adapter  375 ) to the PIV. Likewise, although not shown in  FIGS. 8-11 , the coupler  379  disposed at the end of the secondary catheter  378  can be coupled to a fluid reservoir or the like to place the lumen of the catheter  360  in fluid communication with the fluid reservoir. 
     Once coupled to the PIV and the fluid reservoir, the user can manipulate the transfer device  300  by engaging the first member  311  and the actuator  370  and exerting a force on the actuator  370 . The force exerted on the actuator  370  moves the actuator  370  and the second member  313  in the distal direction relative to the first member  311 , thereby placing the transfer device  300  in the second configuration, as indicated by the arrow BB in  FIG. 10 . More specifically, the actuator  370  moves the second member  313  from a proximal position to a distal position relative to the first member  311 , while the actuator  370  remains in a relatively fixed position (e.g., its proximal position) relative to the second member  313 . For example, in some embodiments, the arrangement of the first member  311 , the second member  313 , and/or the actuator  370  can be such that a relative movement thereby is controlled in a desired manner. Specifically, the second member  313  can be maintained substantially in the proximal position relative to the first member  311  until the force is applied (e.g., either directly or indirectly) to the second member  313  that is sufficient to move the second member  313  relative to the first member  311 . In a similar manner, the actuator  370  can be maintained substantially in the proximal position relative to the second member  313  until a force is applied on the actuator  370  that is sufficient to move the actuator  370  relative to the second member  313 . 
     As shown in  FIG. 10 , the actuator  370  and the second member  313  are collectively moved relative to the first member  311  in response to the applied force on the actuator  370 . As such, a portion of the force moves the second member  313  within the first member  311  (e.g., the protrusion  314  within the channel  312 ), while the actuator  370  is retained in a substantially fixed position relative to the second member  313 . Thus, a force sufficient to move the second member  313  relative to the first member  311  is less than a force sufficient to move the actuator  370  relative to the second member  313 . Such an arrangement can, for example, ensure that the second member  313  is relative to the first member  311  prior to the actuator  370  being moved relative to the second member  313 . 
     As shown in  FIG. 10 , the movement of the second member  313  to the distal position relative to the first member  311  advances the guide member  330  (coupled thereto) in the BB direction to a position in which at least the distal end portion of the guide member  330  is disposed in and extends past an end of the PIV. More specifically, as the second member  313  is moved to its distal position, the guide member  330  is concurrently advanced through a port or “basket” of the PIV (not shown). As described above, the guide member  330  is configured to have a stiffness and/or is formed from a material(s) with a hardness or durometer that is sufficient to pass through the port of the PIV substantially without kinking, breaking, bending, plastically deforming (e.g., permanently deforming), etc. Moreover, the guide member  330  can have a length and hardness that is sufficient to pass through any suitable PIV to dispose at least the distal end portion in a distal position relative to the end of the PIV. In some instances, the guide member  330  can be arranged such that when the second member  313  is in its distal position relative to the first member  311 , the distal end portion of the guide member  330  is disposed in a vascular structure and at least partially outside of the PIV. Furthermore, with the actuator  370  maintained in a relatively fixed position relative to the second member  313 , the distal end portion of the catheter  360  is maintained within the guide member  330 , as shown in  FIG. 10 . 
     Once the second member  313  in its distal position, the applied force exerted on the actuator  370  can move the actuator  370  from its proximal position to its distal position relative to the second member  313 . For example, the portion of the applied force that was operable in moving the second member  313  relative to the first member  311  is instead operable in moving the actuator  370  from its proximal position to its distal position relative to the second member  313 , as indicated by the arrow CC in  FIG. 11 . The movement of the actuator  370  to its distal position advances the catheter  360  in the CC direction to a position in which at least the distal end portion of the catheter  360  is disposed in and extends past the PIV (e.g., a second position and/or a desired or predetermined position). The catheter  360  can be advanced such that the distal end portion of the catheter  360  extends beyond the distal end portion of the guide member  330  to be disposed in the vascular structure and at least partially outside of the PIV and the guide member  330  (e.g., at a predetermined position). With the catheter  360  advanced, for example, to the second position (e.g., the predetermined position), the lumen of the catheter  360  can receive a flow of bodily fluid, which can flow therethrough and into the fluid reservoir. For example, in some embodiments, the fluid reservoir can be an evacuated reservoir such as a Vacutainer® tube, which can exert a suction force through the lumen of the catheter  360 . Thus, the bodily fluid (e.g., blood) is drawn through the lumen of the catheter  360  and the lumen of the secondary catheter  378  and into the fluid reservoir. In this manner, a phlebotomist can collect (e.g., draw) a given amount of blood through an existing peripheral intravenous line without the need for additional needle sticks. 
     As described herein, in some embodiments, the predetermined distance can be based on, for example, one or more characteristics associated the vasculature anatomy of the patient. In some instances, for example, the PIV can be a Jelco® 1.0 in, 20-gauge catheter and the catheter  360  can be advanced to a position such that a distance between the distal tip of the catheter  360  and the distal tip of the PIV is between about 0.0 mm and about 50.0 mm. In the embodiment shown in  FIGS. 8-11 , for example, the predetermined distance can be about 15.0 mm beyond the distal end of the PIV when the catheter  360  is in the second position. As described above with reference to  FIGS. 3-7 , in some instances, the successful aspiration of a volume of blood from the vein through the catheter  360  can be based at least in part on one or more characteristics associated with the vascular anatomy. For example, in some instances, disposing the distal end of the catheter  360  at about 15.0 mm from the distal end portion of the PIV can, in some instances, place the distal end of the catheter  360  in position within the vein receiving a desired volumetric flow of blood (e.g., a branch is disposed between the catheter  360  and a valve and/or any other suitable venous arrangement). 
     In some instances, however, the second position of the catheter  360  may be such that the distal end of the catheter  360  is disposed in a portion of the vein having a flow of blood insufficient for aspiration. As such, the user can engage the actuator  370  to move the catheter  360  in the distal direction or the proximal direction to place the distal end of the catheter  360  in a portion of the vein having a flow of blood sufficient for aspiration through the catheter  360 . In other words, the predetermined distance can be any suitable distance within, for example, a predetermined range of distances (e.g., between about 0.0 mm and about 50.0 mm). 
     Once a desired volume of blood is transferred to, for example, a fluid reservoir such as an evacuated fluid reservoir or tube (e.g., coupled to the coupler  379 ), the user can retract the actuator  370 , which in turn moves the catheter  360  in a proximal direction from the second position toward the first position. The user can then decouple the device  300  from the adapter  375  and/or the PIV and decouple the fluid reservoir from the coupler  379 . In some instances, the device  300  can then be safely discarded. 
     In some instances, it may be desirable to rotate the catheter  360  relative to the first member  311 , thereby rotating the distal end portion within the vascular structure (e.g., to prevent a suctioning of the distal end portion to a wall of the vascular structure). In such instances, the user can, for example, rotate the actuator  370  and the second member  313  relative to the first member  311 . More specifically, manipulation of the actuator  370  by the user can result in a rotation of both the actuator  370  and the second member  313  relative to the first member  311 . As described above, the channel  312  can have a cross-sectional shape and/or area at or near the proximal end portion of the first member  311  that is associated with and/or slightly larger than a size of the protrusion  314 , thereby defining the rotational range of motion of the second member  313  when disposed in the proximal position (e.g., about 30 degrees, about 60 degrees, about 90 degrees, about 120 degrees, about 180 degrees, about 210 degrees, or more). In some instances, such rotation of the actuator  370  and the second member  313  can, for example, reduce a likelihood of the distal end portion of the catheter  360  forming suction against a wall of the vascular structure (e.g., a vein). In some instances, it may be desirable to rotate the second member  313  as the actuator  370  is being moved toward its distal position, as described in the &#39;799 publication. 
     While the fluid transfer device  300  is particularly shown and described above with reference to  FIGS. 8-11 , in other embodiments, any suitable fluid transfer device can be used to access a vein via a PIV and to place a catheter in a desired position within the vein or within the PIV to aspirate a volume of blood from the patient. For example,  FIGS. 12-14  illustrate a fluid transfer device  400  for phlebotomy through a peripheral intravenous line or catheter in a first configuration and second configuration, respectively, according to an embodiment. The fluid transfer device  400  (also referred to herein as “transfer device”) is configured to couple to and/or otherwise engage an indwelling peripheral intravenous catheter (PIV) to transfer fluid from (e.g., aspiration of blood) and/or transfer fluid to (e.g., infusion of a drug or substance) a vein of a patient, as described in further detail herein. The transfer device  400  can be any suitable shape, size, and/or configuration. For example, as shown in  FIGS. 12-14 , the transfer device  400  includes at least an introducer  410 , a catheter  460  (or cannula), and an actuator  470 . In some embodiments, the transfer device  400  can be similar to and/or substantially the same as any of those described in U.S. patent application Ser. No. 15/014,834 entitled, “Devices and Methods for Fluid Transfer Through a Placed Peripheral Intravenous Catheter,” filed Feb. 3, 2016 (referred to henceforth as the “&#39;834 application”), the disclosure of which is incorporated herein by reference in its entirety. As such, some aspects of the transfer device  400  are not described in detail herein and should be considered substantially similar to such aspects of the transfer devices described in the &#39;834 application unless explicitly expressed otherwise. 
     The introducer  410  of the transfer device  400  can be any suitable configuration. For example, in some embodiments, the introducer  410  can be an elongate member having a substantially circular cross-sectional shape. The introducer  410  has an outer surface  435  and defines an inner volume  413  within which at least a portion of the catheter  460  and at least a portion of the actuator  470  are movably disposed. Although not shown in  FIGS. 12-14 , a proximal end portion of the introducer  410  can include an opening or port configured to movably receive a portion of the catheter  460 . As such, a first portion of the catheter  460  can be disposed within the inner volume  413  and a second portion of the catheter  460  can be disposed outside of the inner volume  413 . A distal end portion of the introducer  410  includes and/or is coupled to a lock  450  configured to physically and fluidically couple the introducer  410  to the PIV, as described in further detail herein. 
     As shown in  FIGS. 12-14 , the outer surface  435  of the introducer  410  includes a set of ribs  436  distributed along at least a portion of the introducer  410 . More particularly, each rib  436  extends widthwise along at least a portion of the introducer  410  with each rib  436  successively distributed lengthwise along at least the portion of the introducer  410 . In this manner, the outer surface  435  defines alternating local minima and local maxima arranged along the portion of the length of the introducer  410 , as described in detail in the &#39;834 application. The arrangement of the transfer device  400  is such that a portion of the actuator  470  is configured to be advanced along the outer surface  435  forming the set of ribs  436  as a user moves the actuator  470  relative to the introducer  410 , which in turn, vibrates the actuator  470  (and the catheter  460  coupled thereto). In some instances, this vibration can, for example, facilitate the advancing of the catheter  460  through a portion or the transfer device  400 , a portion of the PIV, and/or a portion of the vasculature. Moreover, in some instances, the vibration can provide a user with a haptic, tactile, and/or audible indicator associated with a position of the catheter  460  relative to the introducer  410  and/or PIV, as described in detail in further detail herein. 
     As described above, the inner volume  413  is configured to receive a portion of the catheter  460  and a portion of the actuator  470 , as shown in  FIGS. 13 and 14 . In some embodiments, an inner surface of the introducer  410  that defines the inner volume  413  can have, for example, a tortuous cross-sectional shape (not shown in  FIGS. 12-14 ) such that an axis defined by a first portion of the inner volume  413  is parallel to and offset from an axis defined by a second portion of the inner volume  413 . In such embodiments, the first portion of the inner volume  413  can be spaced apart from the second portion of the inner volume  413  without being fluidically isolated therefrom. In some embodiments, the introducer  410  can define a slot, channel, track, opening, and/or the like that is in fluid communication with the inner volume  413 . In some embodiments, the tortuous cross-sectional shape of the inner volume  413  is such that the second portion cannot be viewed (e.g., is out of the line of sight) via the slot or the like in fluid communication with the first portion of the inner volume  413 , which in turn, can limit and/or substantially prevent contamination of at least the catheter  460  disposed therein, as described in detail in the &#39;834 application. 
     As described above, the lock  450  of the transfer device  400  is included in and/or coupled to the distal end portion of the introducer  410 . The lock  450  can be any suitable shape, size, or configuration. In some embodiments, the lock  450  is substantially similar to those described in detail in the &#39;834 application. As such, the lock  450  can selectively engage and/or contact the PIV to couple the introducer  410  thereto. In some embodiments, the shape, size, and/or arrangement of the lock  450  is such that the lock  450  forms three points of contact with the PIV  405 . In some embodiments, such an arrangement can provide structural rigidity and/or support to the PIV as a portion of the lock  450  (e.g., a proboscis or the like) is inserted into a portion of the PIV as well as, structural rigidity and/or support to the catheter  460  as the catheter  460  is moved therethrough. 
     The catheter  460  of the transfer device  400  is movably disposed within the inner volume  413  defined by the introducer  410  (e.g., the second portion of the inner volume  413 ) and is coupled to the actuator  470 . In some embodiments, the catheter  460  can be moved (e.g., via movement of the actuator  470 ) between a first position and a second position to transition the transfer device  400  between the first configuration and the second configuration, respectively. More specifically, at least a portion of the catheter  460  is disposed within the inner volume  413  and/or the lock  450  when the catheter  460  is in the first position ( FIG. 13 ) and at least a portion of the catheter  460  extends beyond the introducer  410  and lock  450  to place a distal end of the catheter  460  in a position within the PIV or a position distal to the PIV when the catheter  460  is in the second position ( FIG. 14 ), as described in further detail herein. As shown in  FIGS. 12-14 , a proximal end portion of the catheter  460  and/or a secondary catheter coupled to the actuator  470  and in fluid communication with the catheter  460  is configured to extend through the opening and/or port defined by the proximal end portion of the introducer  410 . In this manner, a proximal end portion of the catheter  460  and/or the secondary catheter can be coupled to a fluid reservoir, fluid source, syringe, and/or the like, which in turn, places the catheter  460  in fluid communication therewith. 
     The catheter  460  can be any suitable shape, size, and/or configuration. In some embodiments, the catheter  460  can be substantially similar to the catheters described in detail in the &#39;834 application. In some embodiments, at least a portion of the catheter  460  can have an outer diameter (e.g., between a 16-gauge and a 26-gauge) that is substantially similar to or slightly smaller than an inner diameter defined by a portion of the lock  450 . In this manner, an inner surface of the portion of the lock  450  can guide the catheter  460  as the catheter  460  is moved between the first position and the second position. In some embodiments, such an arrangement can limit and/or can substantially prevent bending, deforming, and/or kinking of the catheter  460  as the catheter  460  is moved between the first position and the second position. In some embodiments, the catheter  460  can have a length that is sufficient to place a distal surface of the catheter  460  in a desired position relative to a distal surface of the PIV when the catheter  460  is in the second position, as described in further detail herein. 
     The actuator  470  of the transfer device  400  can be any suitable shape, size, and/or configuration. In some embodiments, the actuator  470  can be substantially similar to the actuators described in detail in the &#39;834 application. For example, the actuator  470  can include a first portion movably disposed within the inner volume  413  and a second portion movably disposed outside of the inner volume  413  and in contact with the outer surface  435  of the introducer  410 . In this manner, a user can engage the second portion of the actuator  470  and can move the actuator  470  relative to the introducer  410  to move the catheter  460  coupled to the first portion of the actuator  470  between the first position and the second position. With the second portion of the actuator  470  in contact with the outer surface  435 , the actuator  470  can be moved along the set of ribs  436  when the actuator  470  is moved relative to the introducer  410 , which in turn, produces a haptic, tactile, and/or audible output or feedback. In some instances, the haptic, tactile, and/or audible output and/or feedback can provide an indication to the user that is associated with a position of the distal end of the catheter  460  relative to, for example, a distal end of the PIV and/or the introducer. Although not show in  FIGS. 12-14 , in some embodiments, the introducer  410  and/or the actuator  470  can include indicia or the like configured to provide to the user a visual indication associated with the position of the distal end of the catheter  460 . For example, in some embodiments, the introducer  410  can include a gradation or the like that can indicate a distance between, for example, a distal end of the catheter  460  and a distal tip of the PIV. 
     In some embodiments, the transfer device  400  can be disposed in the first configuration prior to use (e.g., shipped, stored, prepared, etc. in the first configuration). In use, a user can manipulate the transfer device  400  to couple the lock  450  to an indwelling PIV. For example, the PIV can be percutaneously inserted into any suitable vein of the forearm  10  or hand  30  described above with reference to  FIG. 1 . As described above, the size and/or configuration of the PIV can be based at least in part on the vein in which the PIV is inserted. For example, in some instances, a portion of the PIV can be disposed within a vein of the forearm  10  (e.g., the basilic vein  11  or the like) that is sufficiently large to receive a 20-gauge PIV. Similarly, the size and/or configuration of the transfer device  400  can be based at least in part on the size of the PIV. For example, in embodiments in which the indwelling PIV is and/or has a 20-gauge catheter, the catheter  460  of the transfer device  400  can be between, for example, 22-gauge and 26-gauge. 
     With the lock  450  coupled to the indwelling PIV, the user can engage the actuator  470  to move the actuator  470  relative to the introducer  410 , which in turn, moves the catheter  460  from the first position (e.g., disposed within the introducer  410  and/or the lock  450 ) toward the second position. In some embodiments, the arrangement of the actuator  470  and the introducer  410  is such that advancing the actuator  470  relative to the introducer  410  produces a haptic output and/or feedback configured to provide and indicator to the user that is associated with position of the distal end of the catheter  460  relative to the introducer  410  and/or the PIV. For example, based on the haptic feedback or the any other suitable indicator, the user can place the catheter  460  in the second position such that the distal surface of the catheter  460  extends a desired distance beyond the distal surface of the PIV. 
     With the catheter  460  in the second position (e.g., with the transfer device  400  in the second configuration shown in  FIG. 14 ), the user can establish fluid communication between a fluid reservoir, fluid source, syringe, and/or the like and the catheter  460 . For example, in some embodiments, the user can couple the catheter  460  (or a secondary catheter not shown) to the fluid reservoir, fluid source, syringe, and/or the like. With the catheter  460  in fluid communication with the fluid reservoir and/or fluid source, the transfer device  400  can then transfer a fluid from the patient or transfer a fluid to the patient via the catheter  460  extending through and beyond the PIV. 
     As shown in  FIG. 14 , in some instances, the catheter  460  can be in the second position when the actuator  470  is in a distal most position. In this manner, the distal surface of the catheter  460  is positioned within the vein at a predetermined distance beyond the distal surface of the catheter  460 . In some embodiments, the length of the catheter  460  can be sufficient to define a predetermined and/or desired distance or length L 4  between the distal surface of the catheter  460  and the distal surface of the PIV when the catheter  460  is in the second position. In some instances, placing the distal surface of the catheter  460  the predetermined and/or desired distance or length L 4  from the distal surface of the PIV can, for example, place the distal surface of the catheter  460  in a desired position within the vein. For example, in some instances, placing the distal surface of the catheter  460  at the predetermined and/or desired distance length L 4  from the distal surface of the PIV can, for example, place the distal surface of the catheter  460  in a position within a vein that is substantially free from debris (e.g., fibrin/blood clots) otherwise surrounding the distal end portion of the PIV. 
     In some instances, the indwelling PIV can substantially occlude at least a portion of the vein within which the PIV is disposed (e.g., either the PIV itself and/or debris forming around the PIV). As such, PIVs are often suited for delivering a fluid rather than aspirating blood. The venous system, however, is a capacitance system and thus, reroutes blood flow through a different vein (e.g., forms a bypass around the occlusion or substantial occlusion). Moreover, the alternate venous structures (i.e., branches) typically rejoin the vein in which the PIV is disposed at a given distance downstream of the PIV and thus, deliver at least portion of the flow of blood that would otherwise be flowing through the vein in which the PIV is disposed. 
     Thus, in some embodiments, the length of the catheter  460  and/or transfer device  400  when in the position and/or second configuration can be based at least in part on characteristics associated with the vascular structure (e.g., vein) within which the PIV and catheter  460  are disposed. For example, in some instances, the distal surface of the catheter  460  is placed within a compartment and/or portion of the vein that receives a flow of blood sufficient to aspirate a volume of the blood through the catheter  460 . In some instances, the compartment and/or portion of the vein can be based on an existence of one or more valves and/or branch vessels in fluid communication vein and/or a position of the one or more valves and/or branch vessels relative to the distal surface of the PIV and/or the distal surface of the catheter  460 . 
     In some instances, for example, the predetermined and/or desired distance can be between about 0.0 millimeters (e.g., the distal surfaces are flush) and about 100 millimeters (mm). In other embodiments, the predetermined and/or desired distance can be between about 10 mm and about 90 mm, between about 20 mm and about 80 mm, between about 30 mm and about 70 mm, between about 30 mm and about 60 mm, between about 40 mm and about 50 mm, or between any other suitable range and subranges therebetween. In some embodiments, for example, the transfer device  400  can be configured such that the actuator  470  can move about 95 mm along the introducer  410  (e.g., the transfer device  400  has a 95 mm stroke) to position the distal surface of the catheter  460  at about 40 mm beyond the distal surface of the PIV to which the transfer device  400  is coupled. In other embodiments, for example, the transfer device  400  can have a 47 mm stroke that positions the distal surface of the catheter  460  at about 20 mm beyond the distal surface of the PIV to which the transfer device  400  is coupled. In still other embodiments, the transfer device  400  can have any suitable stroke length to position the distal surface of the catheter  460  at the predetermined and/or desired distance from the distal surface of the PIV. As described in further detail herein, the stroke length and thus, the predetermined and/or desired distance and/or length L 4  can be based at least in part on the arrangement of the vascular structure in which PIV and catheter  460  are disposed. 
     Vascular Structure Analysis 
     As described above with reference to  FIGS. 1-5 , a portion of a PIV dwelling within a vein obstructs, at least partially, a lumen defined by the vein and thus, restricts a flow of blood therethrough. In addition, an amount of debris such as blood clots/thrombus or fibrin tails, etc. formed around the portion of the PIV often increases with PIV dwelling time, thereby further limiting blood flow through at least a portion of the vein. In some instances, the blood flow through the vein can be restricted to an extent that renders aspiration of blood through the PIV and/or through a catheter disposed at or near a distal end of the PIV unsuccessful or at least impractical. In addition, the obstructions within the vein and/or the restrictions of the flow can increase a turbulence of the blood flow, which in turn, can increase the likelihood of hemolysis (i.e., the shearing of red blood cells). Similarly, the application of more negative pressure through a blood draw catheter to overcome the restrictions in flow can increase a stress on or in the red blood cells that can result in hemolysis. As described herein, however, it is contemplated that vascular structures such as valves and/or branches disposed in the vein and/or in fluid communication with the vein can, for example, sufficiently mitigate the effects of the indwelling PIV, thereby allowing aspiration of blood through a catheter that gains access to the vein via the indwelling PIV as well as reducing a likelihood of hemolyzed blood samples. 
     As described above with reference to the devices  200  and/or  300 , in some instances, advancing a blood draw catheter through an indwelling PIV such that a distal end of the catheter is disposed within, for example, a predetermined range of distances from a distal end of the PIV can place the catheter in a position relative to the vein that receives a volumetric flow of blood sufficient for blood aspiration. For example, the device  200  is configured to couple to the PIV  280  (e.g., dwelling within a vein) and to advance the catheter  260  to, for example, a distal most position (e.g., the second position) such that the distal end of the catheter  260  is disposed approximately 15.0 mm from the distal end of the PIV  280 . In some instances, advancing the catheter  260  relative to the PIV  280  (e.g., by placing the catheter  260  in the second position), an average success rate (or a predicted average success rate) associated with blood aspiration through the catheter  260  increased. 
     In general, it is contemplated and further described herein that the increased success rate associated with blood aspiration through the catheter  260  when the catheter  260  is disposed, for example, in the second position is indicative of one or more relationships between the venous anatomy and a position of a blood draw catheter relative to the venous anatomy and/or an indwelling PIV. Accordingly, a prospective single-center study of the lower arm venous anatomy including the antecubital, forearm, and hand/wrist region was conducted. The venous anatomy of thirty-five (35) healthy adults was imaged using ultrasonic imaging and data on location and frequency of valves, the valves locations and frequency of branches or collateral vessels, and vessel diameters was recorded in areas where intravenous (IV) catheter placement is common. The first 5 subjects served as validation of study methods and ultrasound technique consistency. Data for the subsequent 30 subjects was collected and analyzed. 
     A nurse marked hypothetical IV insertion locations (e.g., locations that would likely be used to access a vein for aspiration) in each subject&#39;s hand/wrist, forearm, and antecubital regions, on each arm—six (6) total sites marked per subject. The nurse and/or a medical technician took 1-2 photographs of each subject&#39;s arms to document where the hypothetical IV insertion site marks were placed. 
     A separate ultrasound technician performed an ultrasonic imaging study capturing the information in a study worksheet. Two-hundred ten ( 210 ) vessels were imaged and the information was recorded, including:
         Position of the IV mark site on anatomic diagram of arm, including distance from crease of the wrist (whether positive or negative).   Distances from each IV mark site to vein valves up to 8 centimeters (cm) centrally.   Distances from each IV mark site to vein branches or collateral vessels up to 8 cm centrally.   Vessel diameters at the IV mark site and immediately central to every vein branch or collateral vessel up to 8 cm centrally.       

     The data is set forth in Table 1, below: 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Branch Distance and Diameter 
               
            
           
           
               
               
               
               
               
            
               
                   
                 PIV Length 
                 PIV Length 
                 PIV Length 
                 PIV Length 
               
               
                   
                 0.00 in/0.00 mm  
                 1.00 in/25.4 mm 
                 1.16 in/29.46 mm  
                 1.25 in/31.75 mm 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Length Past Tip (mm) 
                 64.5 
                   
                 39 
                   
                 35 
                   
                 32.7 
                   
               
               
                 Length Past Hub (mm) 
                 64.5 
                   
                 64.4 
                   
                 64.5 
                   
                 64.5 
                   
               
               
                 No Branches within  
                 23 
                  11% 
                 37 
                  18% 
                 41 
                  20% 
                 44 
                  21% 
               
               
                 80.0 mm 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Branch &gt;= 64.5 mm 
                 11 
                  5% 
                 23 
                  11% 
                 25 
                  12% 
                 28 
                  13% 
               
               
                 Branch &lt;= 64.5 mm 
                 176 
                  84% 
                 150 
                  71% 
                 144 
                  69% 
                 138 
                  66% 
               
               
                 Totals 
                 210 
                 100% 
                 210 
                 100% 
                 210 
                 100% 
                 210 
                 100% 
               
               
                 Dist. &lt;= 64.5 mm  
                 148 
                  70% 
                 134 
                  64% 
                 131 
                  62% 
                 128 
                  61% 
               
               
                 Diam. &gt;=1 mm 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Dist. &lt;= 64.5 mm  
                 28 
                  13% 
                 16 
                  8% 
                 13 
                  6% 
                 10 
                  5% 
               
               
                 Diam. &lt; 1 mm 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 No/Unsuitable Branch 
                 62 
                  30% 
                 76 
                  36% 
                 79 
                  38% 
                 82 
                  39% 
               
               
                   
               
            
           
         
       
     
     Specifically, as shown in Table 1 and  FIGS. 15-18 , data associated with branch vessel characteristics relative to a hypothetical PIV having an effective length of 0.00 in ( FIG. 15 ), an effective length of 1.00 in ( FIG. 16 ), an effective length of 1.16 in ( FIG. 17 ), and an effective length of 1.25 in ( FIG. 18 ) was determined. For example, an ultrasound image of each vein was taken from the hypothetical IV insertion point to 8.0 cm (80 mm) centrally (e.g., in a proximal or downstream direction). Commonly used PIV lengths were considered, in which the PIV having the length of 0.00 in (0.00 mm) would place the distal end of the PIV at the hypothetical insertion site; the PIV having the length of 1.00 in (25.4 mm) would place the distal end of the PIV at about 1.00 in (25.4 mm) from the hypothetical insertion site; the PIV having the length of 1.16 in (29.46 mm) would place the distal end of the PIV at about 1.16 in (29.46 mm) from the hypothetical insertion site; and the PIV having the length of 1.25 in (31.75 mm) would place the distal end of the PIV at about 1.25 in (31.75 mm) from the hypothetical insertion site. 
     The use of a fluid transfer device such as, for example, the transfer devices  300  and/or  400  to aspirate a volume of blood through the indwelling PIV was considered. As described above, the length of the catheter (e.g., the catheter  360 ) can be based at least in part on the venous anatomy. For example, for the transfer device  300 , the distal end of the catheter  360  can extend approximately 15 mm beyond a distal end of, for example, 1.16 in (29.46 mm) PIV, when the catheter  360  is in the distal most position (e.g., a second position). The transfer device  400  is configured such that the catheter  460  extends approximately 30.0 mm beyond a distal end of, for example, the 1.16 in (29.46 mm) PIV, when the catheter  460  is in the distal most position (e.g., a second position). That is to say, the distal surface of the catheter  360  is configured to extend approximately 40 mm beyond a hub of the PIV and/or beyond a hypothetical insertion point while the catheter  460  is configured to extend approximately 64.5 mm beyond the hub of the PIV and/or beyond the hypothetical insertion point. Therefore, when considering the transfer device  400 , for example, the length of the distal surface of the catheter  460  from the distal tip of the PIV catheter (also referred to herein as “L”) when the catheter  460  is in a distal most position and when the effective length of the PIV is 0.00 in (0.0 mm) is approximately 64.5 mm; the length L when the catheter  460  is in the distal most position and when the effective length of the PIV is 1.00 in (25.4 mm) is approximately 39.0 mm; the length L when the catheter  460  is in the distal most position and when the effective length of the PIV is 1.16 in (29.46 mm) is approximately 35.0 mm; and the length L when the catheter  460  is in the distal most position and when the effective length of the PIV is 1.25 in (31.75 mm) is approximately 32.7 mm, as shown in Table 1. 
     An effect on blood flow and/or successful aspiration produced by branch vessels beyond 80.0 mm was not considered. For example, in some instances, a flow rate through the lumen of a catheter has an inverse relationship with the overall length of the catheter. In other words, a catheter having a given inner diameter and a first length can be associated with and/or otherwise produce a lower flow rate that is lower than a flow rate of a catheter having the same given diameter and a second length, less than the first length. Thus, in this example, a flow rate associated with a catheter length of 80.0 mm (8.0 cm or about 3.15 in) beyond the hypothetical insertion point was not considered suitable for use with, for example, a 20-gauge PIV and/or otherwise for use in this study. In other instances, however, a flow rate through a catheter having such a length or a greater length can be sufficient for blood aspiration. In some instances, the catheter  460  of the transfer device  400  can have a length that is associated with a minimal desired flow rate therethrough (e.g., a length such that the distal end of the catheter  460  is about 64.5 mm beyond a PIV hub and/or beyond an insertion point of a PIV. In other instances, a catheter having an inner diameter substantially similar to an inner diameter of the catheter  460  can have a length greater than the length of the catheter  460  while still allowing for a sufficient flow rate therethrough. 
     In a similar manner, and for the purposes of the study described herein, branch vessels having a diameter of 1.0 mm or less were not considered to contribute sufficient blood flow to the vein and thus, were not considered suitable. That is to say, branch vessels having a diameter of 1.0 mm or less were considered to have a volumetric flow rate of blood below a volumetric flow rate threshold. In other instances, however, a branch vessel having a diameter of 1.0 mm can provide a sufficient flow of blood to the vein, such as, for example, in pediatric cases and/or when a PIV is disposed within a vein of the hand or other small vein. Thus, while described above as being based on a size of a branch vessel, in other instances, a branch vessel having any suitable size but having a volumetric flow rate below, for example, the volumetric flow rate threshold may not be suitable. 
       FIG. 15  illustrates a graph  590  showing data associated with a distance of a first branch vessel from the distal tip of the PIV catheter and the branch vessel diameter when the effective length of the PIV is 0.00 in. In this instance, 23 veins (or 11%) were not in fluid communication with branch vessels within the 8.0 cm (80.0 mm or about 3.15 in), as indicated by region  591  in  FIG. 15 ; 11 veins (or 5%) were in fluid communication with branch vessels beyond approximately 64.5 mm, as indicated by region  592  in  FIG. 15 ; and 28 veins (or 13%) were in fluid communication with branch vessels within approximately 64.5 mm but with a diameter of less than 1.0 mm, as indicated by region  593  in  FIG. 15 . As such, for a PIV catheter having an effective length of 0.00 in (0.00 mm), 62 veins (or 30%) were not in fluid communication with a branch vessel or were in fluid communication with an unsuitable branch vessel. In other words, 138 veins (or 70%) were in fluid communication with at least one suitable branch vessel (at least as it relates to blood aspiration via an indwelling PIV catheter). 
       FIG. 16  illustrates a graph  690  showing data associated with a distance of a first branch vessel from the distal tip of the PIV catheter and the branch vessel diameter when the effective length of the PIV is 1.00 in. In this instance, 37 veins (or 18%) were not in fluid communication with branch vessels within the 8.0 cm (80.0 mm or about 3.15 in) from the hypothetical insertion site, 23 veins (or 11%) were in fluid communication with branch vessels beyond approximately 64.5 mm, and 16 veins (or 8%) were in fluid communication with branch vessels within approximately 64.5 mm but with a diameter of less than 1.0 mm, as indicated by regions  691 ,  692 , and  693 , respectively, in  FIG. 16 . As such, for a PIV catheter having an effective length of 1.00 in (25.4 mm), 76 veins (or 36%) were not in fluid communication with a branch vessel or were in fluid communication with an unsuitable branch vessel. In other words, 124 veins (or 64%) were in fluid communication with at least one suitable branch vessel (at least as it relates to blood aspiration via an indwelling PIV catheter). 
       FIG. 17  illustrates a graph  790  showing data associated with a distance of a first branch vessel from the distal tip of the PIV catheter and the branch vessel diameter when the effective length of the PIV is 1.16 in. In this instance, 41 veins (or 20%) were not in fluid communication with branch vessels within the 8.0 cm (80.0 mm or about 3.15 in) from the hypothetical insertion site, as 25 veins (or 12%) were in fluid communication with branch vessels beyond approximately 64.5 mm, and 13 veins (or 6%) were in fluid communication with branch vessels within approximately 64.5 mm but with a diameter of less than 1.0 mm, as indicated by regions  791 ,  792 , and  793 , respectively, in  FIG. 17 . As such, for a PIV catheter having an effective length of 1.16 in (29.46 mm), 79 veins (or 38%) were not in fluid communication with a branch vessel or were in fluid communication with an unsuitable branch vessel. In other words, 121 veins (or 62%) were in fluid communication with at least one suitable branch vessel (at least as it relates to blood aspiration via an indwelling PIV catheter). 
       FIG. 18  illustrates a graph  890  showing data associated with a distance of a first branch vessel from the distal tip of the PIV catheter and the branch vessel diameter when the effective length of the PIV is 1.25 in. In this instance, 44 veins (or 21%) were not in fluid communication with branch vessels within the 8.0 cm (80.0 mm or about 3.15 in) from the hypothetical insertion site, 28 veins (or 13%) were in fluid communication with branch vessels beyond approximately 64.5 mm, and 10 veins (or 5%) were in fluid communication with branch vessels within approximately 64.5 mm but with a diameter of less than 1.0 mm, as indicated by regions  891 ,  892 , and  893 , respectively, in  FIG. 18 . As such, for a PIV catheter having an effective length of 1.25 in (31.75 mm), 82 veins (or 39%) were not in fluid communication with a branch vessel or were in fluid communication with an unsuitable branch vessel. In other words, 118 veins (or 61%) were in fluid communication with at least one suitable branch vessel (at least as it relates to blood aspiration via an indwelling PIV catheter). 
     The mean branch distance and branch diameter were determined and the standard deviations were calculated for effective PIV lengths of 1.00 in (25.4 mm), 1.16 in (29.46 mm), and 1.25 in (31.75 mm), as shown in Table 2 below: 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Mean Branch Distance and Diameter 
               
            
           
           
               
               
               
               
            
               
                   
                 PIV Length 
                 PIV Length 
                 PIV Length 
               
               
                   
                 1.00 in/25.4 
                 1.16 in/29.46 
                 1.25 in/31.75 
               
               
                   
                 mm 
                 mm 
                 mm 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Std.  
                   
                 Std.  
                   
                 Std. 
               
               
                   
                 Mean 
                 Dev. 
                 Mean 
                 Dev. 
                 Mean 
                 Dev. 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Branch Distance 
                  32 mm 
                 20 
                  34 mm 
                 21 
                  35 mm 
                 22 
               
               
                 Branch Diameter 
                 1.6 mm 
                 1.1 
                 1.6 mm 
                 1.2 
                 1.6 mm 
                 1.2 
               
               
                   
               
            
           
         
       
     
       FIG. 19  is a graph  990  illustrating data associated with a predicted flow rate (by percentage) within a portion of the vein and a distance from the distal tip of the PIV catheter disposed therein to a branch vessel in fluid communication with the vein. In this instance, a length of 40.0 mm between a distal surface of a catheter (e.g., the catheter  460 ) and the distal tip of the PIV when the catheter is in the distal most position was proposed (e.g., based at least in part on a flow rate through the catheter), as indicated by line  991  in  FIG. 19 . Moreover, in this instance, a predicted flow rate of more than 50% through the vein was considered sufficient to support aspiration without branch vessels in fluid communication with the vein (e.g., within the 8.0 cm (80.0 mm or about 3.15 in) from the hypothetical insertion site), as indicated by line  992  and region  993  in  FIG. 19 . 
       FIG. 20  is a graph  1090  illustrating another relationship between the predicted flow rate (by percentage) within a portion of the vein and a distance from the distal tip of the PIV catheter disposed therein to a branch vessel in fluid communication with the vein. In this instances, the length of 40.0 mm and the flow threshold of 50% were maintained (from the graph in  FIG. 19 ), as indicated by the lines  1091  and  1092 , respectively, in  FIG. 20 . Veins that were not in fluid communication with a branch vessel (e.g., within the 8.0 cm (80.0 mm or about 3.15 in) from the hypothetical insertion site) and that had a predicted flow rate of less than 50% are indicated by region  1094  in  FIG. 20 . Veins that were in fluid communication with branch vessels that were further than 40.0 mm beyond the distal tip of the PIV catheter and within the 80.0 mm from the hypothetical insertion site are indicated by region  1095  in  FIG. 20 . 
       FIG. 21  is a graph  1190  illustrating data associated with a predicted flow rate (by percentage) within a portion of a vein of the hand (e.g., the hand  30  in  FIG. 1 ), a portion of a vein of the forearm (e.g., the forearm  10  in  FIG. 1 ), and a portion of the antecubital (AC) region (e.g., an antecubital region  28  in  FIG. 1 ) and a distance from the distal tip of the PIV catheter disposed therein to a branch vessel. As shown in the graph  1190 , branches in fluid communication with the vein in the AC region were further from the distal tip of the PIV and the vein had an overall higher predicted flow rate than the vein of the forearm, which in turn, had an overall higher predicted flow rate and was in the fluid communication with branches that were further from the distal tip of the PIV than the vein of the hand. Such results were predictable based at least in part on decreasing vein diameter as the vein extends distally from the AC region to the hand. 
       FIG. 22  is a graph  1290  illustrating data associated with a predicted flow rate (by percentage) within a portion of a vein and a distance from the hypothetical insertion point of the peripheral intravenous catheter into the vein to a branch vessel in fluid communication with the vein. As described above with reference to Table 1 and the graph  590  in  FIG. 15 , 23 veins (or 11%) were not in fluid communication with a branch vessel within the 8.0 cm (80.0 mm or about 3.15 in) from the hypothetical insertion site, as indicated by the region  1291  in  FIG. 22 . Branch vessels within 1.0 in (25.4 mm) of the hypothetical point of PIV catheter insertion were found in 70 veins (or 33%), as indicated by region  1292  in  FIG. 22 . Moreover, 187 veins (or 89%) were in fluid communication with at least one branch vessel; 121 veins (or 58%) were in fluid communication with at least two branch vessels; and 43 veins (or 20%) were in fluid communication with a third branch vessel. 
     As shown in  FIGS. 15-22  and described above in at least Table 1, a predicted flow rate through a vein can be based at least in part on a size and/or diameter of the vein (e.g., whether the vein is in the antecubital region, the forearm, or the hand), the existence of one or more branch vessels in fluid communication with the vein (e.g., within a predetermined distance such as, for example, 8.0 cm), the distance between the branch vessels and the distal tip of the PIV catheter, and a diameter of the branch vessels. Moreover, the success of blood aspiration via a blood draw catheter accessing a vein through an indwelling PIV catheter can be based at least in part on the venous anatomy (just described) and the distance between a distal surface of the blood draw catheter (e.g., the catheters  360  and/or  460 ) and the distal tip of the PIV catheter. 
     For example,  FIGS. 23-28  are graphs illustrating data associated with a predicted rate of success for blood aspiration and a distance within a vein from a distal tip of a PIV catheter to a distal surface of the blood draw catheter (e.g., a hypothetical and/or modeled distance—no catheters were inserted into the body during the study described herein). Scenarios were modeled each of which reflected different inputs and/or characteristics and the predicted rate of success associated with each scenario was calculated, as shown below in Table 3 and Table 4, respectively: 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Inputs 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Flow Threshold (%) 
                 33 
                 33 
                 33 
                 33 
                 33 
                 33 
               
               
                 Applied Tourniquet  
                 0 
                 30 
                 0 
                 30 
                 0 
                 30 
               
               
                 Diameter Change (%) 
                   
                   
                   
                   
                   
                   
               
               
                 Diameter (%) 
                 150 
                 150 
                 150 
                 150 
                 150 
                 150 
               
               
                 Insert Angle 
                 30 
                 30 
                 30 
                 30 
                 30 
                 30 
               
               
                 PIV Exposed 
                 4 
                 4 
                 4 
                 4 
                 4 
                 4 
               
               
                 Central Buffer 
                 Std. 
                 Std. 
                 40.0 
                 40.0 
                 0.0 
                 0.0 
               
               
                 Peripheral Buffer 
                 Std. 
                 Std. 
                 Std. 
                 Std. 
                 0.0 
                 0.0 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Success Rates (Percentage) 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
               
               
                   
                   
               
               
                   
                 15 mm 
                 70% 
                 82% 
                 78% 
                 88% 
                 66% 
                 80% 
               
               
                   
                 25 mm 
                 75% 
                 86% 
                 81% 
                 90% 
                 73% 
                 86% 
               
               
                   
                 30 mm 
                 78% 
                 87% 
                 82% 
                 90% 
                 75% 
                 87% 
               
               
                   
                 35 mm 
                 81% 
                 89% 
                 83% 
                 91% 
                 79% 
                 89% 
               
               
                   
                 40 mm 
                 81% 
                 90% 
                 83% 
                 91% 
                 81% 
                 90% 
               
               
                   
                   
               
            
           
         
       
     
     Characteristics associated with a PIV catheter such as, for example, a Jelco® 1.0 in, 20 gauge catheter and/or characteristics associated with how such a PIV catheter is inserted into a vein were modeled (e.g., simulated, etc.). For example, as shown in Table 3, a PIV insertion angle of approximately 30° (“Insert Angle” in Table 3) was assumed and approximately 4 mm of the PIV catheter was assumed to be exposed or outside of the body (“NV Exposed” in Table 3). In these instances, a threshold diameter of branch vessels as a percentage of a diameter of the blood draw catheter was fixed at 150% (“Diameter (%)” in Table 3). As described in further detail herein, a desired length of the blood draw catheter (e.g., the catheter  360  of the device  300  and/or the catheter  460  of the device  400 ) can be determined based at least in part on a calculated success rate. 
       FIG. 23  is a graph  1390  illustrating the predicted rate of success for blood aspiration under a first scenario (Scenario “1” in Tables 3 and 4). In this example, a flow rate of about 33% around the hypothetical indwelling PIV was assumed, as indicated by the “Flow Threshold (%)” in Table 3. In other words, a 33% occlusion of the lumen of the vein modeled. As shown in Table 3, in this example, a standard buffer size associated with a central branch and a standard buffer size associated with a peripheral branch were modeled. Specifically, the standard buffer size (or desired distance from the branch vessel) for a central branch vessel having a diameter between about 0.0 mm and about 1.0 mm was 2.5 mm; the standard buffer size for a central branch vessel having a diameter between about 1.0 mm and about 2.0 mm was 5.0 mm; the standard buffer size for a central branch vessel having a diameter between about 2.0 mm and about 3.0 mm was 10.0 mm; and the standard buffer size for a central branch vessel having a diameter greater than about 3.0 mm was 20.0 mm. Similarly, the standard buffer size for a peripheral branch vessel having a diameter between about 0.0 mm and about 1.0 mm was 1.0 mm; the standard buffer size for a peripheral branch vessel having a diameter between about 1.0 mm and about 2.0 mm was 5.0 mm; the standard buffer size for a peripheral branch vessel having a diameter between about 2.0 mm and about 3.0 mm was 5.0 mm; and the standard buffer size for a peripheral branch vessel having a diameter greater than about 3.0 mm was 5.0 mm. 
     As described in detail above, the device  300  can be used to aspirate a volume of blood from a vein via an indwelling PIV. In such instances, the reach of the catheter  360  beyond a distal end of an indwelling PIV catheter such as a Jelco® 1.0 in, 20-gauge PIV (e.g., a hypothetical PIV catheter in this case) is about 15 mm and is indicated in  FIG. 23  by the dashed vertical line. The modeled/predicted success rates associated with blood draw through the catheter (e.g., the catheter  360 ) in such instances closely matched empirical results associated with actual use of the catheter for blood aspiration. The close matching of such results, for example, provides validation for the accuracy of the model and/or the assumptions associated with the model. Therefore, based at least in part on the validation of the modeled and/or predicted success rates of the catheter (e.g., the catheter  360 ) disposed at, for example, 15.0 mm beyond the distal end of the PIV (either empirically or hypothetical) it was determined that the model could be used to calculate predicted success rates for aspiration of blood through a hypothetical blood draw catheter based on a distance between a distal surface of the catheter and the distal tip of the PIV catheter (e.g., a hypothetical PIV catheter disposed in the vein). By comparing the predicted success rates, a desired distance between the distal surface of the catheter and the distal tip of the PIV catheter can be determined. For example, in assuming the parameters and/or characteristics shown in column 1 of Table 3, the desired length between the distal surface of the catheter and the distal tip of the PIV catheter was determined to be about 35.0 mm having a predicted overall success rate of about 81% (as indicated in Table 4). 
       FIG. 24  is a graph  1490  illustrating the predicted rate of success for blood aspiration under a second scenario (Scenario “2” in Tables 3 and 4). In this example, the only change from scenario “1” was the application of a tourniquet proximal to the PIV catheter insertion site. In this example, the application of the tourniquet was considered to increase the size of the vein by about 30%. More specifically, the application of a tourniquet downstream of (e.g., proximal to) a PIV insertion point increases the pressure within the vein, which in turn, results in a swelling or increase in diameter of the vein. In some instances, the increase in the diameter of the vein can be based at least in part on the gender of the subject. For example, in some instances, the application of a tourniquet on a male subject can increase a diameter of a vein, for example, by about 25%, while the application of a tourniquet on a female subject can increase a diameter of a vein, for example, by about 45%. In some instances, the increase in diameter of the vein can be based at least in part on a diameter of the vein without the application of a tourniquet. When the application of a tourniquet is considered, for example, to result in a percentage increase in area of a vein, the percentage increase in area is substantially the same for males and females. That is to say, an area increase of a vein resulting from an application of a tourniquet is substantially independent of gender (e.g., is independent of common differences in the size of veins between males and females). In other words, the resultant change on the vein diameter results in an equivalent change in pressure or volume, thus a smaller vein diameter distends to a larger percentage of diameter than a vein having a larger diameter; however, the resultant change in the cross sectional area is substantially equal. As shown in Tables 3 and 4, in this instance, the percentage of increase in the area of the vein was assumed and/or modeled at 30%. Thus, with all other inputs remaining the same, the predicted success rates for aspiration of blood through the blood draw catheter were calculated based on a distance between a distal surface of the catheter and the distal tip of the PIV catheter, as shown in Table 4 and the graph  1490  in  FIG. 24 . By comparing the predicted success rates, a desired distance between the distal surface of the catheter and the distal tip of the PIV catheter was determined to be about 35.0 mm having a predicted overall success rate of about 89% (as indicated in Table 4). 
       FIG. 25  is a graph  1590  illustrating the predicted rate of success for blood aspiration under a third scenario (Scenario “3” in Tables 3 and 4). In this example, the only change from scenario “1” was the assumption that the distal surface of the catheter reached, for example, a central branch vessel or the buffer zone. Specifically, as shown in Table 3, the buffer zone for the central branch was set to 40.0 mm. In other words, the distal end of the catheter can be about 40.0 mm from the central branch while remaining within the “buffer zone” and/or otherwise by being in fluid communication with a vein having a positive effect on a volumetric flow rate through at least a portion of the vein. Thus, by comparing the predicted success rates, a desired distance between the distal surface of the catheter and the distal tip of the PIV catheter was determined to be about 25.0 mm having a predicted overall success rate of about 81%, as indicated in Table 4. 
       FIG. 26  is a graph  1690  illustrating the predicted rate of success for blood aspiration under a fourth scenario (Scenario “4” in Tables 3 and 4). In this example, the only change from scenario “3” was the application of a tourniquet proximal to the PIV catheter insertion site—assuming an increase in the size of the vein by about 30%, as described above. Thus, by comparing the predicted success rates, a desired distance between the distal surface of the catheter and the distal tip of the PIV catheter was determined to be about 25.0 mm having a predicted overall success rate of about 90%, as indicated in Table 4. 
       FIG. 27  is a graph  1790  illustrating the predicted rate of success for blood aspiration under a fifth scenario (Scenario “5” in Tables 3 and 4). In this example, the only change from scenario “1” and/or “3” was the buffer zone associated with both central branches and peripheral branches was decreased to 0.0 mm. That is to say, all assumptions associated with one or more buffer zones surrounding a branch vessel were set to zero. Said another way, in this instance, a branch vessel can affect the likelihood of a successful blood draw through a catheter when a distal end of the catheter is disposed at or proximal to (e.g., beyond) the branch vessel. Thus, by comparing the predicted success rates, a desired distance between the distal surface of the catheter and the distal tip of the PIV catheter was determined to be about 35.0 mm having a predicted overall success rate of about 79%, as indicated in Table 4. 
       FIG. 28  is a graph  2490  illustrating the predicted rate of success for blood aspiration under a sixth scenario (Scenario “6” in Tables 3 and 4). In this example, the only change from scenario “5” was the application of a tourniquet proximal to the PIV catheter insertion site—assuming an increase in the size of the vein by about 30%, as described above. Thus, by comparing the predicted success rates, a desired distance between the distal surface of the catheter and the distal tip of the PIV catheter was determined to be about 35.0 mm having a predicted overall success rate of about 89%, as indicated in Table 4. 
     With the predicted success rates calculated for scenarios 1-6, an overall desired distance between a distal surface of a catheter and a distal tip of a PIV catheter dwelling within a vein was determined to be about 30.0 mm. In other words, blood aspiration via a blood draw catheter using an indwelling PIV catheter is more likely to be successful when the distal surface of the catheter (e.g., the catheter  460  of the device  400 ) is disposed at a distance of about 30.0 mm from the distal tip of the indwelling PIV catheter. While some predicted success rates continued to increase with an increase in distance beyond, for example, 30.0 mm, it was determined that 30.0 mm was desired based on diminishing returns associated with increased lengths of the catheter. Moreover, in some instances, a flow rate through a catheter can be inversely proportional to a length of the catheter. Thus, providing a catheter with a length that places the distal end of the catheter at about 30.0 mm beyond the distal tip of the indwelling PIV can, for example, balance a benefit of potential increase in flow rate through the vein at a further distance with a decreased flow rate through the catheter. 
     While the transfer device  300  is described above as being configured to place the distal end of the catheter  360  approximately 15.0 mm beyond a distal end of a PIV (e.g., a 1.0 in PIV such as a Jelco® 1.0 in, 20-gauge PIV) when the catheter  360  is in a distal most position, and the transfer device  400  is described above as being configured to place the distal end of the catheter  460  approximately 30.0 mm beyond a distal end of a PIV (e.g., a 1.0 in PIV) when the catheter  460  is in a distal most position, it should be understood, that the catheter  360  and the catheter  460  can be placed in any suitable position proximal or distal to the distal end of the PIV within the 15.0 mm and the 30.0 mm, respectively. For instance, a user may manipulate the transfer device  400  by advancing the catheter  460  (or the transfer device  300  by advancing the catheter  360 ) relative to an indwelling 1.0 in PIV to its distal most position. If, however, blood draw is unsuccessful and/or a flow of blood through the catheter  460  is below a desired threshold, the user can, for example, move the catheter  460  in a proximal direction relative to the PIV to place the catheter  460  in a position within the vein receiving a desired flow of blood, as described above with reference to, for example,  FIGS. 2-6 . 
       FIG. 29  is a flowchart illustrating a method  50  of using a fluid transfer device to place a catheter within a vein, via an indwelling peripheral intravenous catheter, at a position suitable for blood aspiration, according to an embodiment. The method  50  includes coupling the fluid transfer device to an indwelling peripheral intravenous line (PIV) at least partially disposed in a vein of a patient, at  51 . The fluid transfer device can be any suitable device configured for fluid transfer through a PIV. For example, in some embodiments, the fluid transfer device can be substantially similar to the fluid transfer devices  300  and/or  400  described above with reference to  FIGS. 8-11  and  FIGS. 12-14 , respectively. In some embodiments, the fluid transfer device can be substantially similar to any of the fluid transfer devices described in the &#39;834 application incorporated by reference above. In other embodiments, the fluid transfer device can include only a catheter or other suitable fluid conduit. As such, the fluid transfer device can include at least an introducer defining a lumen, a catheter movably disposed in the lumen of the introducer, and an actuator coupled to the catheter. As described above with reference to the transfer device  400 , the lumen (or inner volume) of the introducer can have a tortuous cross-sectional shape configured to isolate, at least partially, the catheter disposed in the introducer from a volume outside of the introducer. 
     With the fluid transfer device coupled to the PIV (and/or an adapter coupled to the PIV), the catheter is moved from a first position, in which the catheter is proximal to the indwelling PIV, to a second position, in which at least a portion of the catheter is disposed within the indwelling PIV such that a distal surface of the catheter is disposed at a predetermined distance from a distal tip of the indwelling PIV, at  52 . As described above with reference to the fluid transfer device  400  shown in  FIGS. 12-14 , the introducer can have an outer surface that defines a set of ribs or the like configured to be in contact with a portion of the actuator such that moving the actuator relative to the introducer advances the portion of the actuator along the ribs. In some embodiments, the movement of the actuator along the ribs can produce a vibration of the actuator, which in turn, can produce, for example, a haptic, tactile, and/or audible output. In some instances, the haptic, tactile, and/or audible output can provide to a user an indication associated with a position of a distal end portion of the catheter as the actuator moves the catheter from the first position toward the second position (as described in detail in the &#39;894 application incorporated by reference above). In some embodiments, the introducer can include indicia or the like that can indicate to the user the relative position of the distal end portion of the catheter (e.g., relative to a distal end portion of the PIV). 
     As described above with reference to the transfer device  400 , the actuator is configured to move the catheter to the second position such that the distal surface of the catheter is placed at the predetermined distance from the distal tip of the indwelling PIV. As described in detail above, the predetermined distance can be based at least in part on the venous anatomy of the vein in which the PIV and catheter are disposed. For example, in some instances, the predetermined distance is based at least in part on the existence and/or position of one or more valves within the vein and/or one or more branch vessels in fluid communication with the vein. In some instances, the method  50  can optionally include, for example, determining the venous anatomy associated with the vein prior to coupling the fluid transfer device to the indwelling peripheral intravenous line. This determining of the venous anatomy can be based on, for example, ultrasonic imaging, venogram, or fluoroscopy and/or the like. Thus, based on data associated with the venous anatomy, the distal surface of the catheter can be placed at the predetermined distance from the distal tip of the indwelling PIV. More particularly, the predetermined distance can be a position within the vein and/or relative to the PIV that is associated with a desired likelihood for successful aspiration of a volume of blood through the catheter. 
     As described in detail above, in some instances, the predetermined distance can be such that the distal surface of the catheter is disposed within the vein at a desired distance (e.g., a buffer zone) from a branch vessel in fluid communication with the vein. In some instances, the predetermined distance can be such that at least one of a valve or a branch vessel is in a position along the vein that is between the distal tip of the indwelling PIV and the distal surface of the catheter. That is to say, the distal tip of the PIV can be in a position relative to the vein that is distal to (e.g., upstream of) the valve and/or branch vessel and the distal surface of the catheter can be in a position relative to the vein that is proximal to (e.g., downstream of) the valve and/or branch vessel. As such, the distal surface of the catheter can be placed in a position within the vein that receives a desired volumetric flow rate of blood that is suitable for blood aspiration through the catheter and that would otherwise be reduced by obstructions within the vein (e.g., debris such as fibrin or the like) resulting from the indwelling portion of the PIV. 
     In some embodiments, the predetermined distance can be such that the distal surface of the catheter is in a distal position relative to the distal tip of the indwelling PIV. Similarly stated, the distal surface can be in a position along and/or relative to the vein that is proximal to a position along and/or relative to the vein of the distal tip of the indwelling PIV. Said yet another way, the distal surface of the catheter can be in a position within the vein that is downstream of a position within the vein of the distal tip of the indwelling PIV. As described in detail above, in some embodiments, the predetermined distance can be within a predetermined range of distances between, for example, about 0.0 mm and about 50.0 mm. For example, in some embodiments, the predetermined distance can be 30.0 mm. In some embodiments, the haptic, tactile, audible, and/or visual indication resulting from the movement of the actuator relative to the introducer can be associated with and/or otherwise indicate a distance between the distal surface of the catheter and the distal tip of the indwelling PIV. Thus, when a user determines the distal surface of the catheter is placed at the predetermined distance from the distal tip of the PIV, the user can stop moving the actuator relative to the introducer regardless of whether the actuator is in, for example, a distal most position relative to the introducer. 
     With the catheter in the second position and/or with the distal surface of the catheter being disposed at the predetermined distance from the distal tip of the PIV, a volume of blood is transferred via the catheter from the vein to a fluid reservoir in fluid communication with the catheter, at  53 . The fluid reservoir can be any suitable fluid reservoir such as, for example, a negative pressure container or an evacuated container, a syringe, a sample bottle, and/or the like. In some instances, the method  50  can include establishing fluid communication between the catheter and the fluid reservoir. In other instances, the fluid communication between the catheter and the fluid reservoir can be pre-established (e.g., pre-assembled and/or assembled in a separate process or the like). Thus, with the distal surface of the catheter being disposed within the vein at a position in which a volumetric flow rate is not substantially restricted by obstructions otherwise resulting from the indwelling portion of the PIV catheter, a volume of blood can be transferred from the vein, through the catheter (and thus, the PIV), and into the fluid reservoir. 
     The method  50  includes moving the catheter from the second position toward the first position after a desired volume of blood is transferred to the fluid reservoir, at  54 . In some instances, an actuator can be moved to move the catheter toward the first position and/or to place the catheter substantially in the first position. In other instances, the actuator can be moved to place the catheter in a third position (e.g., a storage or disposal position). The fluid transfer device is decoupled from the indwelling PIV after the catheter is moved from the second position toward the first position, at  55 . Moreover, the fluid reservoir can be removed from fluid communication with the catheter (e.g., decoupled or the like) prior to the catheter being moved toward the first position, after the catheter is moved toward the first position, or after the fluid transfer device is decoupled from the indwelling PIV. With the fluid transfer device decoupled from the indwelling PIV, the fluid transfer device can be safely discarded. In this manner, the fluid transfer device can be used to aspirate a volume of blood from a vein that is accessed via an indwelling peripheral intravenous catheter. 
     While the distal surface of the catheter is described above as being disposed at the predetermined distance from the distal tip of the PIV when the distal surface of the catheter is in a distal most position relative thereto, in other embodiments, the predetermined distance can be a distance between the distal surface of the catheter and the distal tip of the PIV when the distal surface of the catheter is in a proximal position relative to the distal tip of the PIV. For example, in some instances in which the vein is in fluid communication with a branch vessel that is beyond a reach of the catheter (e.g., downstream of the catheter when the catheter is fully advanced relative to the introducer), it may be desirable to advance the catheter to the second position in which the distal surface of the catheter is disposed within the PIV catheter. More particularly, in some such instances, the distal surface of the catheter can be disposed at the predetermined distance from the distal tip of the PIV when the distal surface of the catheter is distal to, for example, a hub of the PIV but proximal to, for example, the distal tip of the PIV. As such, the catheter can be in the second position when the distal surface of the catheter is in a distal position relative to one or more kinks otherwise formed in the PIV catheter. In other instances, the catheter can be in the second position when the distal surface of the catheter is substantially flush with the distal tip of the PIV (e.g., the predetermined distance is about 0.0 mm). Thus, in some instances, the predetermined distance between the distal tip of the PIV and the distal end or surface of the catheter can be, for example, a predetermined range of distances that includes a distance in a proximal direction (e.g., a negative distance) and a distance in a distal direction (e.g., a positive distance), as described in the &#39;834 application incorporated by reference above. Moreover, by passing the catheter through at least a portion of the PIV, the catheter can be configured to “unkink” at least a portion of the PIV whether the distal surface of the catheter is in a proximal position relative to the distal tip of the PIV or a distal position relative to the distal tip of the PIV. In other instances, advancing the catheter to a position such that the distal end of the catheter is distal to the distal tip of the PIV can, for example, remove debris such as fibrin, clots, etc. from the distal tip of the PIV, which in turn, may be sufficient to allow for successful blood draw through the catheter. 
     The embodiments described herein can be used to transfer fluid from a patient or to the patient by accessing a vein via an indwelling PIV. In some instances, the embodiments described herein can be used to aspirate a volume of blood efficiently while maintaining the integrity of the sample. While extracting blood, the transfer device  300  and/or  400 , for example, can be configured to receive and/or produce a substantially laminar (e.g., non-turbulent or low turbulent) flow of blood through the transfer device  300  and/or  400 , respectively, to reduce and/or substantially prevent hemolysis of the blood as the blood flows through the transfer device  300  and/or  400 , respectively. 
     As described above, the transfer device  300  and/or  400 , for example, can be manipulated to place the distal surface of the catheter  360  and/or  460 , respectively, at a predetermined and/or desired distance from a distal surface of the PIV. In some instances, for example, the predetermined and/or desired distance can be based at least in part on the venous anatomy (e.g., the existence of one or more valves and/or branch vessels), as described in detail above with reference to the vascular structure analysis. Specifically, in some instances, the predetermined and/or desired distance can be about 5.0 mm, about 10.0 mm, about 15.0 mm, about 20.0 mm, about 25.0 mm, about 30.0 mm, about 35.0 mm, about 40.0 mm, about 45.0 mm, about 50.0 mm, and/or any suitable distance or fraction of a distance therebetween. In other instances, a predetermined and/or desired distance can be zero. That is to say, in some instances, it may be desirable to position the distal surface of the catheter  260  substantially flush to and/or with the distal tip of the PIV catheter. Moreover, in some instances, the predetermined and/or desired distance can be proximal to the distal tip of the PIV catheter (e.g., the distal end of the blood draw catheter is disposed within the PIV catheter) or the predetermined and/or desired distance can be distal to the distal tip of the PIV catheter (e.g., the distal end of the blood draw catheter is disposed outside of the PIV catheter and within, for example, a vein). As described above, it should be understood that when referring to a predetermined and/or desired distance, such a distance can be, for example, within a predetermined and/or desired range of distances. In some instances, the predetermined and/or desired range of distances can be based at least in part on the venous anatomy and/or one or more characteristics associated with an indwelling PIV such as, for example, a PIV length. 
     Although the predetermined and/or desired distance is described above as being a positive distance, that is, the distal surface of the catheter  360  and/or  460  is flush with or distal to the distal tip of the PIV catheter, in other embodiments, a predetermined and/or desired distance can be associated with a distal surface of a catheter (e.g., the catheter  360  of the transfer device  300  or the catheter  460  of the transfer device  400 ) being in a proximal position relative to the distal tip of the PIV catheter (e.g., a negative distance). For example, in some instances, the predetermined and/or desired distance can be between about 0.0 mm (e.g., the distal surfaces are flush) to about −50 mm, between about −10 mm and about −40 mm, between about −20 mm and about −30 mm, or between any other suitable range or subranges therebetween. In some instances, the predetermined and/or desired distance can be less than −50 mm (e.g., the distal surface of the catheter  360  and/or  460  is more than 50 mm proximal to the distal surface of the PIV). In some instances, the catheter  360  and/or  460 , for example, can be placed in the second position such that a distal end portion of the catheter  360  and/or  460  remains within the PIV in a position distal to, for example, a kink or the like. For example, an indwelling PIV can have one or more portions that are kinked and/or bent (e.g., a portion of the PIV where the PIV catheter couples to a hub). In such instances, the predetermined and/or desired distance can be such that the distal surface of the catheter  360  and/or  460  is distal to the portion of the PIV that forms the kink while remaining within the PIV, which in turn, can result in a fluid flow path being sufficiently unrestricted to allow blood aspiration therethrough, as described in the &#39;834 application incorporated by reference herein. 
     Although not shown in  FIGS. 8-11 and/or 12-14 , the transfer device  300  and/or  400 , respectively, can be coupled to any suitable PIV while still being configured to place the distal surface of the catheter  360  and/or  460 , respectively, at the predetermined and/or desired distance relative to the distal tip of the PIV catheter. In some instances, use of a PIV can include coupling the PIV to an IV extension set and/or an adapter (e.g., a single port adapter, a Y-adapter, a T-adapter, or the like). Thus, while the transfer devices  300  and/or  400  are described herein as being coupled to a PIV, it should be understood that the transfer devices  300  and/or  400  can be coupled to either a PIV or an adapter coupled thereto based on the situation and/or configuration. The transfer devices  300  and/or  400  can be configured to couple to any suitable commercially available PIV, adapter, and/or extension set. For example, the lock  450  of the transfer device  400  can have a size, shape, and/or configuration that can allow the lock  450  to be coupled to various PIVs, adapters, and/or extension sets, as described in detail in the &#39;834 application incorporated by reference above. Moreover, the catheter  460  can have a length that is sufficient to place the distal surface of the catheter  460  at a desired position relative to the distal tip of the PIV when the catheter  460  is in the second position regardless of the lock  450  coupling to an adapter (e.g., IV extension set) or directly to the PIV. 
     The embodiments described herein can be used in a variety of settings (ER, in-patient, etc.). The following scenario of withdrawing a sample volume of blood from a patient is provided by way of example. In some instances, a peripheral intravenous (PIV) line and/or catheter is inserted into a vein of a patient following standard guidelines and an extension set and/or adapter is attached. The PIV catheter can remain within the vein for an extended period and can provide access to the vein for the transfer of fluids (e.g., saline, blood, drug compounds, etc.) to the patient. That is to say, after placement, the PIV is an indwelling PIV catheter. When it is time to draw a volume blood, a user (e.g., nurse, physician, phlebotomist, and/or the like) can stop the transfer of fluid to the patient, if it is transferring fluid, for approximately 1-5 minutes to allow the fluid to disperse from the PIV insertion site. To draw the blood sample, the user attaches a transfer device (e.g., the transfer device  400 ) to a port and/or suitable portion of the extension set and/or adapter and transitions the transfer device from a first configuration (e.g., a storage configuration as shown in  FIGS. 12 and 13 ) to a second configuration, in which a portion of a catheter included in the transfer device extends through the peripheral IV and into the vein (e.g., as shown in  FIG. 14 ). 
     As described in detail above with reference to the transfer device  400 , a distal surface of the catheter can be disposed at a predetermined and/or desired distance from a distal tip of the PIV catheter when the transfer device is in the second configuration to place the catheter in fluid communication with a portion of the vein that receives an unobstructed and/or uninhibited flow of blood. For example, the distal surface of the catheter can be in a distal position relative to the distal tip of the PIV catheter and at least one branch vessel, valve, and/or the like in fluid communication with the vein. Once the catheter is in the desired position, the user can attach one or more negative pressure collection containers, tubes, and/or syringes to the transfer device to extract a volume of blood. In some instances, the volume of blood can be a first volume of blood that can be discarded and/or at least temporarily stored apart from a subsequent sample volume of blood (e.g., typically a volume of about 1-3 milliliters (mL) but up to 8-10 mL of blood can be a “waste” or “pre-sample” volume). In some instance, the waste volume can include contaminants, non-dispersed residual fluids, and/or the like. After the collection of the waste volume, the user can couple, for example, one or more negative pressure containers (e.g., sample containers) to the transfer device to collect a desired blood sample volume. Once the sample volume is collected, the transfer device can be transitioned from the second configuration toward the first configuration and/or a third configuration (e.g., a “used” configuration). The transfer device can then be decoupled from the extension set and/or adapter and safely discarded. In some instances, after collecting the sample volume but prior to transitioning the transfer device from the second configuration, the waste or pre-sample volume, for example, can be reinfused into the vein via the transfer device. 
     While various embodiments are described above, it should be understood that they have been presented by way of example only, and not limitation. Where schematics and/or embodiments described above indicate certain components arranged in certain orientations or positions, the arrangement of components may be modified. Although various embodiments have been described as having particular features and/or combinations of components, other embodiments are possible having a combination of any features and/or components from any of embodiments as discussed above. 
     For example,  FIGS. 30-61  illustrate various transfer device configurations, each according to an embodiment. Each of the embodiments shown in  FIGS. 30 and 61  can be substantially similar in form and/or function to, for example, the transfer device  400  described above with reference to  FIGS. 12-14 . As shown, for example, in  FIGS. 30-39  a transfer device that is substantially similar in at least function to the transfer device  400  can have any suitable configuration and/or arrangement that can enhance and/or increase an aesthetic appeal and/or the ergonomics of the transfer device. In some embodiments, a transfer device that is substantially similar in at least function to the transfer device  400  can have a design configured to display indicia such as instructions for use, company name, size and/or compatibility (e.g., “20-gauge,” “22-gauge,” and/or the like, as shown in  FIGS. 40-43 . Similarly, as shown in  FIGS. 44 and 45 , a lock mechanism, coupler, clip, and/or any other suitable portion can be configured to display indicia and/or otherwise provide an indication to a user of, for example, an intended use of the transfer device. 
     In some embodiments, any portion of the transfer devices (e.g., including transfer devices  300  and  400  described above) can have a color or the like configured to provide an indication of the intended use of the transfer device. In some embodiments, the color of at least a portion of any transfer device described herein can be according to an industry standard, a U.S. Food and Drug Administration (FDA) rule or standard, and/or the like. For example, in some embodiments, any suitable portion of the transfer devices described herein can be shaded and/or colored yellow, indicating a 24-gauge catheter is included therein; blue, indicating a 22-gauge catheter is included therein; pink, illustrating a 20-gauge catheter is included therein; green, illustrating a 18-gauge catheter is included therein; and/or any other suitable color coding. 
     As shown, for example, in  FIGS. 46-52 , any suitable portion of a transfer device such as, for example, the transfer device  400  described above, can have a substantially uncolored and at least partially transparent (clear or light grey) introducer (e.g., the introducer  410 ) and a color coded partially transparent or opaque lock (e.g., the lock  450 ) and/or actuator (e.g., the actuator  470 ). In some embodiments, a transfer device can also include a color coded partially transparent or opaque coupler (e.g., the coupler  379  included in the transfer device  300 ), as shown in  FIGS. 50-52 . In some embodiments, a transfer device can include a white, opaque lock, as shown in  FIG. 52 . In some embodiments, such as those shown in  FIGS. 53-55 , an introducer, lock, actuator, and/or coupler can each be color coded and partially transparent or color coded and opaque, or a combination thereof. In some embodiments, such as those shown in  FIGS. 56-61 , a transfer device can include a white, opaque introducer and any suitable combination of color-coding described above. 
     While embodiments are particularly shown and described herein, various changes in form and details may be made. Any of the aspects and/or features of the embodiments shown and described herein can be modified to affect the performance thereof. For example, the ribs in the set of ribs  436  of the introducer  410  and the actuator  470  can have any suitable shape, size, configuration, and/or arrangement to produce a desired set of characteristics associated with the movement of the actuator  470  relative to the introducer  410 , as described above. By way of another example, any of the components of the transfer device  400  can be formed from any suitable material that can result in a desired hardness, durometer, and/or stiffness of that component. As another example, the size and/or shape of the transfer device  400  can be increased or decreased based on a desired usage. For example, in some embodiments, a transfer device having a size that is smaller than the transfer device  400 , but otherwise being substantially similar in form and/or function to the transfer device  400  can be used with or for pediatric patients. 
     Where methods and/or schematics described above indicate certain events and/or flow patterns occurring in certain order, the ordering of certain events and/or flow patterns may be modified. Additionally certain events may be performed concurrently in parallel processes when possible, or may be performed sequentially. Moreover, while the fluid transfer devices  300  and/or  400  are described above as being used in the method  50 , in other instances, any suitable device can be used in any of the methods described herein (including the method  50 ). For example, in some embodiments, a user can manipulate a catheter to advance the catheter from a first position to a second position relative to an indwelling peripheral intravenous line, as described above with reference to the method  50 . In such instances, the catheter can be independent of a fluid transfer device such as the fluid transfer devices  300  and/or  400 . In other words, a separate and/or independent catheter can be used in any of the methods described herein including, for example, the method  50 . Said another way, a fluid transfer device that includes only a catheter can be used in any of the methods described herein including, for example, the method  50 .