JP2013150923A - Operation method of needle assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operation method of a needle assembly for suppressing leakage of blood from the needle assembly.SOLUTION: The needle assembly includes: a needle housing for demarcating an inside; a cannula which has first and second puncture ends extending from first and second end parts and communicates fluid between them; a porous vent body for dividing the inside of the housing into a first and a second chambers; and a means which establishes negative pressure against an external environment of the needle assembly in the second chamber by establishing communication of the fluid between the second puncture end and a vacuum collection container to flow the blood in the first chamber via the cannula and so as to be in touch with the porous vent body. The leakage prevention means is in operation so as to pull the blood in the second chamber through holes of the porous vent body on the basis of the negative pressure established in the second chamber so that when communication of the fluid between the second puncture end and the vacuum collection container is canceled, the blood enclosed in the cannula may leave the first puncture end and may be displaced toward the second chamber.

Description

  The present invention relates to an apparatus for collecting a blood sample by performing venipuncture on a patient. More particularly, the present invention provides multiple sample blood collection needles that allow a phlebotomist to determine whether a venous entry has occurred when collecting a blood sample from a patient into a vacuum blood collection tube. The present invention relates to a method for operating an assembly.

  Venipuncture is the primary method used to obtain blood samples for clinical trials. In the procedure of performing venipuncture, the phlebotomist must follow several steps simultaneously. Such steps include assessing the patient's overall physical and psychological state in order to properly select the site and technique for venipuncture. The phlebotomist must also select appropriate, corresponding equipment, implement bleeding control techniques, and properly collect and identify fluid samples for testing. Because such factors may adversely affect the duration of venous dilatation and venipuncture procedures, phlebotomists must identify all of these simultaneous factors.

  Various venipuncture devices have been developed to address the above problems. These devices include a product that is intended to assist a phlebotomist to confirm that a vein entry has been made. For example, see Patent Document 1 and Patent Document 2. Such an apparatus includes a needle assembly having a housing defining a chamber therein. A single cannula pointed at both ends is secured to the housing. The intravenous (IV) end of the cannula is adapted to penetrate the patient's vein. The non-patient end of the cannula has a sealable sleeve and is adapted to penetrate a penetrable stopper located within the vacuum vessel.

US Pat. No. 5,222,502 US Pat. No. 5,303,713

  Upon entry into the vein by the intravenous end of the cannula, blood flows into a sealable sleeve through the cannula and a housing chamber that is transparent or translucent for visualization (“flashback”). Once air is evacuated from the flashback chamber, the internal blood is pressurized each time the sealable sleeve is pushed toward the chamber of the housing when the vacuum vessel is activated.

  Due to the length of time between the entry into the vein and the flashback, the see-through chamber has no immediate indication of entry into the vein, so the phlebotomist has not achieved satisfactory entry into the vein You may mistakenly believe that. Thus, a phlebotomist may unnecessarily repeat a venipuncture procedure that requires replacement of the vacuum container and / or the needle assembly itself. Such repetitive work prolongs the physical and emotional discomfort endured by the patient. In such cases, the phlebotomist may use a blood collection set that provides some entry instructions, so that it will bear the cost of the discarded tube as well as the cost of the blood collection set.

  Accordingly, an improved method of operating a blood collection device is provided that allows blood to flow directly into a flashback chamber via a relatively short needle, thereby providing an immediate indication of successful entry into a vein. It would be desirable.

  The present invention provides a method of operating a needle assembly for collecting at least one fluid sample into a vacuum vessel for clinical testing. The needle assembly is transparent or translucent with sufficient dead space for blood to flow into the flashback chamber for visualization by the user to confirm successful entry into the vein with an internal venting mechanism A simple housing.

  In one embodiment, the present invention includes a housing defining an interior of the housing, a cannula having a patient piercing tip extending from the first end of the housing and a non-patient piercing tip extending from the second end of the housing. The present invention relates to a method for operating a needle assembly. The non-patient puncture tip and the patient puncture tip are in fluid communication with each other via a cannula so that the only communication path between the housing interior and the external environment is via the patient puncture tip. Yes. The porous vent is positioned within the housing such that the cannula divides the interior of the housing into a first chamber and a second chamber in fluid communication with the first chamber. The porous vent includes a hole for the passage of blood from the first chamber to the second chamber. The first chamber and the second chamber are configured to allow blood to flow through the cannula to the first chamber without sealing the porous vent when the patient needle tip is inserted into the patient. ing. When the vacuum container is applied to the non-patient puncture tip, blood is drawn from the first chamber and air is drawn from the second chamber, thereby with respect to the external environment of the needle assembly. Establish negative pressure inside. Thereafter, blood is drawn into the first chamber and via a porous vent with a negative pressure maintained in the second chamber.

  In one embodiment, the cannula includes a first end with a patient puncture tip and a second end with a non-patient puncture tip, between the first end and the second end. An opening provides fluid communication between the cannula and the first chamber of the housing. In an alternative embodiment, the cannula comprises a first cannula having a patient-side piercing tip, and the needle assembly further comprises a second cannula containing a non-patient-side piercing tip, The second cannula is generally axially aligned and separated by a gap in fluid communication with the first chamber of the housing. A sleeve may extend around the non-patient puncture tip.

  In certain embodiments, the first end of the housing comprises an elongated longitudinal first portion having a first diameter, and the second end of the housing is a first diameter of the first portion. A second portion having a larger second diameter is provided. In such an embodiment, a porous vent may be located within the housing between the first portion having the first diameter and the second portion having the second diameter. Alternatively, the porous vent may be located inside the housing at a location that spans a transition between a first diameter at the first location and a second diameter at the second location.

  In a further embodiment, a method for preventing blood leakage from a needle assembly is provided. The method includes a needle housing defining a housing interior, a cannula having a patient-side piercing tip extending from a first end of the needle housing, and a non-patient-side piercing extending from a second end of the needle housing. The tip, the non-patient-side puncture tip, and the patient-side puncture tip are in fluid communication with each other via a cannula, and are located inside the housing, and the inside of the housing is divided into a first chamber and a second chamber. Receiving blood through the patient-side puncture tip into the first chamber of the needle assembly with a porous vent. The cannula is in fluid communication with the first chamber such that the only communication path between the housing interior and external environment is via the patient piercing tip, and the porous vent is the first A hole for the passage of blood from one chamber to the second chamber. Fluid communication between the non-patient puncture tip and the vacuum collection container allows blood contained in the first chamber to be drawn into the vacuum collection container and air to pass through the porous chamber out of the second chamber. Established to be drawn through the gas. As such, a negative pressure is established in the second chamber relative to the external environment of the needle assembly such that blood flows through the cannula into the first chamber and contacts the porous vent. Is done. The blood is then displaced from the patient puncture tip based on the negative pressure established in the second chamber after the patient puncture tip is removed from the patient's vasculature. As such, it is pulled toward the second chamber through the pores of the porous vent.

  In addition, a further step breaks fluid communication between the non-patient puncture tip and the second vacuum collection container before drawing blood into the second vacuum collection container via the patient puncture tip and cannula. And subsequent establishment of fluid communication between the non-patient puncture tip and the second vacuum collection container.

  In a further embodiment, the present invention provides a method for collecting a blood sample from a patient into a vacuum blood collection tube using a blood collection assembly having a patient needle tip and a non-patient needle tip and a housing having a flashback visualization chamber. Is directed to. The method includes a housing having a porous vent positioned to divide the interior of the housing into a first chamber and a second chamber forming a flashback visualization chamber, the first chamber and the first chamber The second chamber is configured such that air is drawn with the blood sample from the second chamber through the porous vent into the vacuum blood collection tube, thereby establishing a negative pressure in the second chamber. Using a needle assembly. The negative pressure is such that after the patient needle tip is removed from the patient, the negative pressure in the second chamber draws blood from the patient needle tip toward the second chamber, thereby causing blood from the patient needle tip. Blood is drawn into the first chamber to prevent it from leaking and contact the porous vent.

1 is a cross-sectional view of an exemplary embodiment of a needle assembly of the present invention. It is sectional drawing of 2nd Embodiment. It is sectional drawing of 3rd Embodiment. It is sectional drawing of 4th Embodiment. FIG. 2 is a schematic view of the needle assembly of FIG. 1 before use. FIG. 6 is a schematic diagram similar to FIG. 5 but showing the first signs of venous entry. It is the schematic of 5th Embodiment. FIG. 5 is a perspective view of a needle assembly having a flash chamber in a further embodiment. FIG. 9 is a rear perspective view of a needle assembly having the flash chamber of FIG. 8. FIG. 9 is an exploded view of a needle assembly having the flash chamber of FIG. FIG. 9 is a cross-sectional view of a needle assembly having the flash chamber of FIG. FIG. 11B is an enlarged cross-sectional view of a portion of the needle assembly of FIG. 11A. FIG. 5 is a cross-sectional view of a needle assembly having a flash chamber used in connection with a blood collection assembly in a further embodiment. FIG. 12B is an enlarged cross-sectional view of a portion of the needle assembly of FIG. 12A.

  The present invention provides a visual indication of entry into a vein (“flashback”) upon collection of blood or other fluid sample from a patient into one or more vacuum blood collection tubes, and an IV cannula when removed from the patient. A needle assembly for blood collection that suppresses leakage of blood or fluid samples from the blood is provided.

  Various embodiments of the present invention are illustrated in FIGS. Referring to FIG. 1, this embodiment includes a needle assembly 210 comprising a housing 212 having a fluid inlet end 214, a fluid outlet end 216, and a frustum-shaped outer wall 218 extending between the ends. Is directed. Outer wall 218 defines housing interior 220. The housing 212 further includes a cylindrical inner wall 224 that extends substantially concentrically to the cylindrical outer wall 218 from the fluid inlet end 214 to the vent plug 900 in the housing interior 220. The cylindrical inner wall 224 and the vent plug 900 define a flashback chamber 226.

  Needle assembly 210 also includes a fluid inlet cannula 236 having an outer end forming a sharp bevel and an inner end 244 secured to the fluid inlet end 214 of housing 212. The fluid inlet cannula 236 is further characterized by a generally circular lumen that extends between the ends and communicates with the interior of the housing 212.

  Needle assembly 210 further includes a fluid outlet cannula 252. The outlet cannula 252 includes a blunt inner end 254, an outer end forming a sharp bevel, and a generally circular lumen extending between the ends. The portion between the ends of the outlet cannula 252 is secured to the outlet end 216 of the housing 212. The outlet cannula 252 has its inner end 254 passing substantially concentrically within the inner wall 224 and the inner end 254 of the outlet cannula 252 is substantially axially aligned with the inner end 244 of the inlet cannula 236. Is attached. In addition, the inner end 254 of the outlet cannula 252 is spaced a small distance from the inner end 244 of the inlet cannula 236. An axial gap of less than 0.5 mm between the inner end 254 of the outlet cannula 252 and the inner end 244 of the inlet cannula 236 may result in inconsistent flashback.

  The cylindrical inner wall 224 is dimensioned relative to the outlet cannula 252 to achieve the desired blood flow through the assembly 210 and to achieve an effective flashback indication. Specifically, the cylindrical inner wall 224 is preferably dimensioned to provide a radial clearance of about 0.2 mm around the outlet cannula 252 as shown by dimension “c” in FIG. ing. This gap achieves a substantially linear blood flow within the flashback chamber 226 and prevents blood cell destruction. In addition, the small radial gap between the cylindrical inner wall 224 and the outlet cannula 252 allows blood drips to spread thinly within the flashback chamber 226 across the radial gap, resulting in a very small amount of Provides enlarged flashback instructions with blood. Thus, an easily visualized flashback indication is achieved immediately upon the first appearance of blood from the inner end 244 of the inlet cannula 236.

  Needle assembly 210 further includes a sealable sleeve 261 that is attached to fluid outlet end 216 of housing 212 and covers outer end 258 of outlet cannula 252 when sealable sleeve 261 is unbiased. It is out. However, the sealable sleeve 261 is exerted by the decompressed tube stopper to bias the outer end 260 of the outlet cannula 252 through both the sealable sleeve 261 and the decompressed tube stopper. In response to the applied pressure, it can be folded as is known in the art.

  The above embodiment has been described with reference to a vent plug. However, any ventilation mechanism is appropriate. The venting mechanism is formed, for example, from an aqueous, ie, a hydrophobic, matrix or carrier material that is typically impregnated or impregnated with, or includes, a hydrophilic material that swells upon contact with a hydrous substance. It may be a porous ventilation plug. The hydrophobic carrier material may be, but is not limited to, high density polyethylene, polytetrafluoroethylene, ultra high molecular weight polyethylene, nylon 6, polypropylene, polyvinylidene fluoride and polyethersulfone. The swellability of the hydrophilic material thereby provides a sealing function in the vent when in contact with blood. For example, a biological phenomenon that blocks the vent by coagulation and / or cell aggregation, a superabsorbent material that seals the vent by swelling when contacted with an aqueous fluid, or a one-way valve (e.g., a plastic film covering the vent A porous flap that seals when it comes into contact with blood using a thin flap such as rubber, plastic or a deformable seal such as a duckbill valve, or a deformable wrap on the vent. It is also possible to use quality vent plugs. It should be noted that a combination of these various mechanisms is also possible.

Figures 2 to 4 show embodiments with different vent plugs. FIG. 2 shows a vent plug 900a located at the end of the cylindrical inner wall 224a and incorporated in the recess 301 of the non-patient sidewall 300 inside the housing. FIG. 3 shows a vent plug in a position similar to the vent plug of FIG. 2, however, vent plug 900b has a shoulder 901b. FIG. 4 shows a vent plug 900c located in both the cylindrical inner wall 224c and the recess 301 of the non-patient side wall 300 inside the housing and having a shoulder 901c. The arrangement of the vent plug in each of these embodiments is such that air does not flow out of the flashback chamber 226 and into the housing interior 220 without passing through the vent mechanism (900a, 900b _, 900c).

  FIGS. 5 and 6 show the needle assembly 210 of FIG. 1 before and after a normal venipuncture where the needle assembly 210 is coupled to a holder (not shown) and punctures the patient's skin for entry into the vein. Provides a schematic depiction. Upon entering the vein, blood enters the IV cannula 236 and flows toward the flashback chamber 226. Blood flows from the inlet cannula 236 into the space between the inlet and outlet cannulas so that the blood flows to both the outlet cannula 252 and the flashback chamber 226. At this point, the flashback chamber 226 indicates a successful entry into the vein, reducing the volume of air present in the housing 212 shown in FIG. The air that was at atmospheric pressure prior to entry into the veins in the lumen of the IV cannula 248, the flashback chamber 226, the housing interior 220, and the non-patient cannula 262 is thus subject to the effects of venous pressure. Hence experiencing compression. Accordingly, this air is forced through the IV cannula 236 shown in FIG. 6 into the flashback chamber 226 and through the vent plug into the chamber 220. Blood flow into the housing interior 220 is allowed to flow through by pressurized air but is blocked by a vent plug 900 that seals upon contact with blood, thereby being compressed (to venous pressure). Air is trapped in the housing interior 220. Blood flow throughout the needle assembly stops once the pressure in the chamber 226 and the venous pressure are equal.

  Once the steps described in the previous paragraph have occurred and the venous entry has been visually confirmed by the phlebotomist there, the outer end 260 of the second cannula 252 is placed in the container as is known in the art. A vacuum vessel (not shown) is inserted into the holder so as to pass through the stopper. When the stopper is pierced by the second cannula 252, a negative pressure gradient is transmitted to the chamber 226 and blood flow from the chamber 226 to the container occurs.

The needle assembly described above should desirably be small for convenient use, but must be configured to ensure reliable and fast flashback. The occurrence of flashback in the needle assembly described and illustrated above operates according to the ideal gas law. Specifically, at very low densities, all gases and vapors approximate ideal gas behavior and follow the “Boile-Charles law” given by:
P ₁ V ₁ = P ₂ V ₂
here,
P ₁ is the pressure of air in the needle assembly before needle insertion,
P ₂ is the pressure of the air in the needle assembly after entry into the vein,
V ₁ is the volume of air in the needle assembly prior to entry into the vein, and V ₂ is the volume of air in the needle assembly after entry into the vein.

The design parameters should keep the needle device as small as possible for easy use, while ensuring the proper volume defined by the above equation. 5 and 6 provide a schematic depiction of the needle assembly 210 of FIG. 1 to illustrate the application of the ideal gas law. In this regard, A identifies the volume of lumen 248 through inlet cannula 236. B means the total volume of the housing interior 220, the flashback chamber 226, the lumen 242 through the outlet cannula 252 and the sealable sleeve 261. Referring back to the above equation, P ₁ is the pressure in the needle assembly 210 prior to use and is therefore approximately equal to atmospheric pressure. Atmospheric pressure varies slightly from time to time and from place to place. However, for the purposes of this analysis, the atmospheric pressure P ₁ is assumed to be 760 mm Hg. V ₂ in the above equation is the volume of dead space in the needle assembly 210 after entry into the vein. More particularly, after entry into the vein, blood will fill the lumen 248 of the inlet cannula 236, thereby reducing the volume occupied by the gas in the remainder of the needle assembly 210, and thus the needle assembly. Increase the air pressure in the rest of the solid 210. A needle assembly with dimensions generally as shown in FIG. 1 has a pressure P ₂ of about 790 mm Hg at venous pressure (depending on the tourniquet). V ₁ in the above equation defines the volume of the total dead space in the needle assembly 210 prior to use and is therefore equal to A + B shown in FIG. V ₂ defines the dead space in the device after entry into the vein with the lumen 248 of the inlet cannula 236 filled with blood. Therefore, V ₂ in the above equation is equal to B. These input parameters may be used as shown in the application of the ideal gas law equation below to determine the minimum desired size for each component of the needle assembly 200.
P ₁ V ₁ = P ₂ V ₂
P ₁ / P ₂ = V ₂ / V ₁
760/790 = B / (A + B)
0.962 = B / (A + B)
0.962 (A + B) = B
0.038B = 0.962A
B = 25.3A

  Thus, the dead space in the housing 212, outlet cannula 252 and sleeve 261 is advantageously at least 25.3 times the volume defined by the lumen 248 through the inlet cannula 236, most advantageously. About 26 times the volume of the lumen 248. However, other configurations are possible and function as described herein.

  The immediate reaction when the decompressed tube is placed in communication with the outlet cannula 252 is to draw blood from the vein into the tube (not shown). A maximum pressure gradient is always maintained between the vein and the decompressed tube. Thus, the axially aligned inlet cannula 236 and outlet cannula 252 provide an unobstructed path for blood flow from the vein to the decompressed tube.

  When the required tube is filled with blood, the needle assembly is removed from the vein. The sealability of the vent plug 900 will prevent the pressurized air in the housing interior 220 from moving into the flashback chamber 226 and the inlet cannula 236, which will promote blood dripping from the IV cannula tip. Suppress.

  The above-described embodiments show structurally separate inlet and outlet cannulas that are axially aligned with each other and placed in an end-to-end relationship with each other. However, the principles of the present invention described above are also achieved by a single cannula that has a transverse slot or opening formed in the flashback chamber. For example, FIG. 7 schematically illustrates a needle assembly 310 with a housing 312 that is substantially identical to the housing 212 described and illustrated above. Needle assembly 310 differs from needle assembly 210 in that a single end needle cannula 336 is provided and penetrates the entire housing 312. More particularly, needle cannula 336 includes a venous entry end 338, a non-patient end 340, and a lumen 342 extending therebetween. The portion of cannula 336 in inner wall 324 includes a slot or opening 344 that provides communication between lumen 342 and flashback chamber 336 in inner wall 324. Needle assembly 310 functions substantially the same as needle assembly 210 described and illustrated above.

  8-11 illustrate a needle assembly in a further embodiment of the present invention. In one embodiment of the needle assembly described with respect to FIGS. 1-7, the housing interior includes a vent plug 900 that seals the flashback chamber 226/326 from the housing interior 220/320. In such a previous embodiment, the vent plug seals when blood flows into the flashback chamber, thereby (moving air from the flashback chamber 226/326 to the housing chamber 220/320 during the initial flush procedure). To prevent the pressurized air that may accumulate in the housing chamber 220/320 from moving in the opposite direction toward the inlet cannula. In the embodiment of FIGS. 8-11, a porous vent is disposed within the housing that divides the housing into two chambers having a size and dimensions for establishing a predetermined volume. Like to do. Furthermore, the porous vent remains porous to blood and does not seal when it comes into contact with blood. Desirably, the porous vent does not contact the blood in the initial flush instruction, and such contact occurs at a later time during use of the assembly, as will be described in more detail below.

  For example, FIGS. 8-11 illustrate a needle assembly 410 similar to that described in connection with FIGS. 1-6 above. As shown in FIGS. 8-11, the needle assembly 410 includes a housing 412 having a fluid inlet end or first end 414 and a fluid outlet end or second end 416. . Needle assembly 410 includes an outer wall 418 that defines the interior of the housing. The outer wall 418 extends generally longitudinally at the first end 414 and forms an elongated longitudinal first portion 419 having a first diameter. At the second end 416, the outer wall 418 forms a second portion 421 having a second diameter that is generally greater than the first diameter of the first portion 419. As a result, the housing 412 can form a structure having a generally T-shaped cross section. The outer wall 418 at the second end 416 is another element 428 that can be attached to the body portion 430 that forms the housing 412, thereby assisting in the manufacture and assembly of the needle assembly 410. The first portion 419 and the second portion 421 can be arranged in various arrangements relative to each other, as described herein, as long as the air transfer function between them is possible.

  Needle assembly 410 further includes a fluid inlet cannula 436 extending from first end 414 of housing 412. The fluid inlet cannula 436 includes an outer end defining a first piercing tip, such as a sharp bevel at the patient side piercing tip 438, and extends into and secured to the first end 414 of the housing 412. Can be attached. The fluid inlet cannula 436 is further characterized by a generally circular lumen extending between the ends and in communication with the interior of the housing 412.

  Needle assembly 410 also includes a non-patient piercing tip extending from second end 416 of housing 412. This may be accomplished by providing a needle assembly 410 comprising a second cannula in the form of a fluid outlet cannula 452, as can be seen in FIG. Specifically, the end of the fluid outlet cannula 452 defines a sharp bevel that forms a non-patient puncture tip 462. A fluid outlet cannula 452 extends into the second end 416 of the housing 412 and may be fixedly attached thereto. The fluid outlet cannula 452 is further characterized by a generally circular lumen communicating with the interior of the housing 412. Outlet cannula 452 is mounted within housing 412 such that inner end 464 passes substantially concentrically such that outlet cannula 452 is substantially aligned axially with the inner end of inlet cannula 436. Desirably, this causes the outlet cannula 452 to extend into the housing 412 so that the inner end 464 of the outlet cannula 452 extends to a position near the inner end 439 of the inlet cannula 436. This is achieved by mounting in a nearby position. As can be seen in FIG. 11B, the inner end 464 of the outlet cannula 452 is spaced a small distance from the inner end 439 of the inlet cannula 436, thereby allowing blood to enter the flashback chamber 426 around the outlet cannula 452. For the flow, an axial gap is formed between them. The distance between the inner end 464 of the outlet cannula 452 and the inner end 439 of the inlet cannula 436 forming an axial gap is based on the patient's blood pressure after venipuncture and the flashback chamber 426. Enough to bring blood flow to. In some embodiments, axial gaps less than 0.5 mm may result in inconsistent flashback.

  As can be seen from FIG. 11B, the fluid inlet cannula 436 and the fluid outlet cannula 452 are within the housing 412 to achieve both the desired flow of blood through the assembly 410 and an effective flashback indication. Positioned and dimensioned. Specifically, the wall 418 of the housing 412 is dimensioned to provide a radial clearance of about 0.2 mm in the region surrounding the inner end 464 around the outlet cannula 452. This gap achieves a substantially linear blood flow within the flashback chamber 426 and prevents blood cell destruction. In addition, the small radial gap in the region surrounding the inner end 464 between the inner surface of the wall 418 and the outlet cannula 452 causes blood drips to spread thinly across the radial gap in the flashback chamber 426. And provides enlarged flashback instructions with very small amounts of blood. Thus, as soon as the first appearance of blood in the flashback chamber 426, an easily visualized flashback indication is achieved. It is contemplated that the inner end 464 of the outlet cannula 452 can be partially supported within the housing 412 as long as blood flow to the flashback chamber 426 is achieved around the inner end 464.

  In an alternative arrangement, a single cannula is provided, similar to the embodiment described in connection with FIG. Such an arrangement is depicted in the embodiment of FIGS. 12A and 12B (shown in connection with the blood collection assembly described in more detail herein). In such an arrangement, the fluid inlet cannula and the fluid outlet cannula represent a single cannula 470 having a patient piercing tip 438, a non-patient piercing tip 462, and a lumen 442 extending therebetween, and The body of the cannula 470 is fixedly attached to a portion of the housing 412 and penetrates the housing 412 entirely. A portion of cannula 470 extending through housing 412 may have one or more such as a slot or opening 444 to provide communication between lumen 442 and flashback chamber 436 in housing 412. Includes an opening. It is contemplated that any number of such openings may be included for blood flow to the flashback chamber 436, but in the embodiment seen in FIGS. 12A and 12B, two separate on either side of the cannula 470 The opening is shown.

  Returning to the embodiment of FIGS. 8-11, the needle assembly 410 further includes a sealable sleeve 461 attached to the fluid outlet end 416 of the housing 412. This includes an elastomeric element that provides a mounting protrusion 429 at a second end 416 of a housing 412, such as element 428, and a sealable sleeve 461 is friction fitted or attached to the protrusion 429. Is achieved by doing Sealable sleeve 461 covers non-patient piercing tip 462 at the outer end of exit cannula 452 when sealable sleeve 461 is in an unbiased state. However, the sealable sleeve 461 is depressurized to bias the outer end 460 of the outlet cannula 452 by the sealable sleeve 461 and the decompressed tube stopper, as is known in the art. In response to the pressure exerted by the stoppers of the formed tube.

  The embodiment of FIGS. 8-11 further includes a porous vent 910 positioned within the housing 412. A porous vent 910 is used to divide the housing 412 into two different chambers, a first chamber represented by a flashback chamber 426 and a second chamber represented by a secondary chamber 427. Is located within. The porous vent 910 does not include a hydrophilic material that swells upon contact, but may be composed of any suitable material described above with respect to the vent plug 900. In this way, the porous vent 910 is adapted to vent air through it and exhibits a porous structure including a plurality of pores that allow blood to pass therethrough. As will be discussed in more detail herein, during use of the needle assembly 410, the internal holes in the porous vent 910 may at least partially due to the negative pressure established in the secondary chamber 427. Filled with blood. Such filled holes combined with negative pressure in the secondary chamber 427 prevent air flow between the secondary chamber 427 and the flashback chamber 426, as will be described in more detail as follows: Providing fluid resistance to the flow of blood through the porous vent 910.

  Desirably, the porous vent 910 is positioned between the first portion 419 and the second portion 421 within the housing 412. As such, the first portion 419 of the housing 412 essentially defines the flashback chamber 426 and the second portion 421 of the housing 412 essentially defines the secondary chamber 427. Instead, the porous vent 910 is positioned within the housing 412 at a location across the transition between the first diameter of the first portion 419 and the second diameter of the second portion 421. Also good. In any event, the porous vent 910 is a generally cylindrical member with a central opening that axially surrounds a portion of a cannula, particularly a fluid outlet cannula 452.

The internal volume of the housing 412 is determined not only by the volume of the flashback chamber 426 and the secondary chamber 427, but also by the sum of the volumes represented by the pores of the porous vent 910. Such internal volume is a characteristic of the needle assembly 410, in particular the ability of the secondary chamber 427, to establish a negative pressure therein when a reduced tube is applied to the needle assembly 410 in use. Therefore, it is configured to provide a characteristic that a part of the air in the interior is at least partially exhausted. Such negative pressure in the secondary chamber 427 draws blood through the pores of the porous vent 910 based on when the blood contacts the porous vent 910 and partially fills the pore. In certain embodiments of the invention, the overall internal volume of the housing 412 is from about 300 mm ³ to about 400 mm ³ . Such a volume is a needle for a normal venipuncture that draws a blood sample from the patient using a needle cannula having a normal standard (gauge) for venipuncture, as is known in the art. This is particularly beneficial for the intended use of assembly 410. With such an internal volume, the porous vent 910 is desirably about 5 percent of the total total volume of the housing 412, including the volume of the secondary chamber 427 and the volume of the pores in the porous vent 910. To about 20 percent, and desirably, is positioned inside the housing to define a flashback chamber 426 having a volume that represents about 7 percent to about 12 percent of the total total volume of the housing 412. The ratio of the flashback chamber 426 to the total total volume of such a housing 412 ensures that the flashback chamber 426 has sufficient volume to properly visualize the initial flush, and desirably flashback blood. Based on the initial accumulation of pressure in the secondary chamber 427 caused by the venous pressure exerted on the chamber 426, blood is prevented from fully contacting the porous vent 910 during the initial venipuncture. Such volume ratio is effective for the intended use, as described in more detail herein, where blood flowing into the flashback chamber 426 during the initial venipuncture is porous to the vent 910. And at least a portion of the air is withdrawn from the secondary chamber 427 based on the application of the vacuum blood collection tube to the needle assembly 410. In this way, the secondary chamber 427 is porous from within the flashback chamber 426 and from within the fluid inlet cannula 426 when the patient-side puncture tip 438 is removed from the patient and exposed to the external environment. The blood can be effectively drawn into and through the vent 910 of the body toward the secondary chamber 427. In one particular embodiment, the total internal volume of the housing 412 is about 380 mm ³ , the flashback chamber 426 has a volume of about 30 mm ³ , the secondary chamber 427 has a volume of about 300 mm ³ , And the hole of the porous ventilation body 910 has shown the volume of about 50 mm < ³ >.

  The needle assembly 410 is assembled as follows. The fluid inlet cannula 436 includes a housing such that an open inner end 439 is positioned at a first portion 419 inside the housing 412 and a patient-side piercing tip 438 extends outwardly from the first end 414. Located through the first end 414 of 412. The fluid outlet cannula 452 has an open inner end 464 with a slight gap therebetween, near the inner end 439 of the fluid inlet cannula 436 at the first portion 419 inside the housing 412. It is positioned in the housing 412 through the opposite end so that the patient-side puncture tip is positioned extending outwardly from the second end 416. The fluid inlet cannula 436 and the fluid outlet cannula 452 may desirably be attached by known methods via medical grade adhesive.

  In an alternative embodiment that includes only a single cannula 470, such cannula 470 has a patient-side piercing tip 438 extending outwardly from the first end 414 and a non-patient-side piercing tip 462 having a second end. Mounted within the housing 412 such that the opening 472 is located in the first portion 419 inside the housing 412 with the 416 extending outwardly.

  There, a porous vent 910 is inserted into the housing 412 and positioned over the fluid outlet cannula 454 (or over a single cannula 470), after which the element 428 is attached to the second end 416. Encloses the inside of the housing 412. Therefore, a sealable sleeve 461 is attached to the protrusion 429. In this way, the interior of the housing 412 is closed from the external environment, with the only path for fluid communication between the interior of the housing 412 and the external environment being provided through the patient piercing tip 438.

  The needle assembly 410 thus assembled is used in conjunction with the blood collection holder 800 as depicted in the embodiment shown in FIG. Such an assembly is completed through the open end at the rear of the blood collection tube holder 800, with the entire needle assembly 410 at least the patient puncture tip 438 of the inlet cannula 436 and at least a portion of the front end of the blood collection tube holder 800. It is inserted to the part that extends through. In embodiments where the second portion 421 of the needle assembly 410 is radially larger than the first portion 419, such insertion and arrangement is such that the flashback chamber 426 extends from the front end of the blood collection holder 800. The secondary chamber 427 can be completely contained within the interior space within the blood collection tube holder 800.

  In use, the needle assembly 410 may be provided attached to the blood collection tube holder 800. The patient-side puncture tip 438 is inserted through the patient's skin and into the patient's vasculature, preferably a vein. During venipuncture, the housing 412 is generally closed, and the sealable sleeve 461 closes the sole outlet of the housing 412 (ie, the fluid outlet cannula 452) so that the closed environment within the housing 412 is present. Is achieved. The patient's blood pressure surrounds the inner end 464 of the outlet cannula 452 from the patient-side piercing tip 438 to the fluid inlet cannula 436 and from the inner end 439 (or opening 472 in the embodiment of FIG. 12). Creates a flow of blood into the flashback chamber 426. The transparency or translucency of the housing 412 allows visualization of the blood in the flashback chamber 426 and provides an indication that venipuncture has been achieved.

  Since the interior of the housing 412 is a closed environment, the flow of blood into the flashback chamber 426 is within the fluid outlet cannula 452 in addition to the flashback chamber 426, the porous vent 910 and the secondary chamber 427. In the interior of the housing containing the air, the air is trapped and the trapped air is slightly pressurized there. The flashback chamber 426 and the secondary chamber 427 have their volumes allowing blood to flow into the flashback chamber 426 during this initial venipuncture, but within the pores of the porous vent 910 and the secondary The accumulation of air pressure in the static chamber 427 prevents complete contact of the blood with the porous vent 910, and desirably the blood partially penetrates the porous vent 910 during the initial venipuncture. Even their sizes and dimensions are configured to prevent even contact.

  After such initial venipuncture and flush visualization, a sample collection container, such as a vacuum blood collection tube (not shown), having a negative pressure therein, is generally contained within the tube holder 800 as is generally known in the art. Inserted into. Such a vacuum container stopper (not shown) moves in contact with the sealable sleeve 461, causing the non-patient puncture tip 462 to pierce through the sealable sleeve 461 and the vacuum container stopper. At this point, fluid communication is established between the non-patient puncture tip 462 and the interior of the vacuum collection container. The negative pressure in the vacuum collection container draws the blood collected in the flashback chamber 426 into the fluid outlet cannula 452 and the vacuum collection container. Along with the blood in the flashback chamber 426, the negative pressure in the vacuum collection container evacuates at least a portion of the air from the flashback chamber 426 and from the secondary chamber 427 through the hole in the porous vent 910. Pull into and into the collection container. In addition, the close proximity and arrangement of the fluid outlet cannula 452 and the fluid inlet cannula 426 allows blood to be drawn from the flashback chamber 426 and the secondary chamber 427 at the same time that blood is drawn into the fluid inlet cannula 436 and the patient. To be drawn from.

  Such air entrainment reduces the pressure in flashback chamber 426 and secondary chamber 427 and establishes a negative pressure with respect to the patient's blood flow and with respect to the external environment. This negative pressure established within the housing 412, and particularly within the flashback chamber 426 and secondary chamber 427, causes the fluid in the fluid inlet cannula 436 and with the blood in contact with the porous vent 910. Withdraw additional blood from the patient into the flashback chamber 426. As such blood fills the flashback chamber 426, the blood fully contacts the surface of the porous vent 910 extending into the flashback chamber 426 and begins to fill the pores of the porous vent 910. Such filling of the pores of the porous vent 910, which resides directly at the interface between the porous vent 910 and the flashback chamber 426, blocks the flow of air through the porous vent, but Seals in that the blood does not inflate the porous vent material, i.e. it does not block air flow, but instead simply physically fills the cavity in the porous vent Does not work completely. Further, since a part of the air in the secondary chamber 427 is drawn from the secondary chamber 427, the secondary chamber 427 means a chamber closed with a negative pressure with respect to the external environment. Yes. Thus, the secondary chamber 427 has a porous vent 910 at the interface of the flashback chamber 426 that is filled with blood to the pores of the porous vent 910 and the blood in the flashback chamber 426. Without releasing air in the opposite direction from the secondary chamber 427, thereby effectively preventing air flow through the porous vent 910 due to the filled holes. , Continues to have a retraction action towards the secondary chamber 427 through the pores of the porous vent 910. The retraction created by the negative pressure in the secondary chamber 427 is based on blood filling the pores of the porous vent 910 and based on the tortuous path created by the pores of the porous vent 910 Because of the fluid resistance, it is a slow retraction with slowed fluid movement.

  At this point, both the vacuum collection container and the secondary chamber 427 are under negative pressure with respect to the external environment (and with respect to the patient's blood flow) and therefore both are drawn from the fluid inlet cannula 436. This mutual retraction action causes the blood contained in the flashback chamber 426 to be collected in a vacuum collection container via the secondary chamber 427 through the pores of the porous vent 910 or the fluid inlet cannula 436. However, instead, in principle, an equilibrium is established in the flashback chamber 426 such that it remains in steady state in the flashback chamber 426 in principle. The vacuum pressure in the vacuum collection container is due to the close proximity and alignment of the fluid outlet cannula 452 and fluid inlet cannula 426, as well as the equilibrium established in the flashback chamber 426 (vacuum collection container and reduced secondary pressure). (Based on the reverse pulling force between the dynamic chambers 427), drawing blood directly from the patient via the fluid inlet cannula 436. The continuous drawing of blood into the vacuum collection container causes a gradual increase in pressure within the collection container.

  Once the vacuum collection container is filled with the desired amount of blood, the container is removed from the non-patient puncture tip 462 so that the sealable sleeve 461 is closed over the non-patient puncture tip 462. , Release fluid communication between the non-patient side puncture tip 462 and the vacuum collection container. When there is no such pull-in due to the negative pressure of the vacuum collection tube, the negative pressure in the secondary chamber 427 slightly pulls in the blood in the flashback chamber 426 through the hole of the blood porous vent 910. To do. However, such entrainment is slow and slow due to the tortuous path of blood flow through the pores of the porous vent 910.

  An additional vacuum is obtained by placing the second vacuum collection container in the holder 800 and puncturing the stopper to establish fluid communication between the non-patient puncture tip 462 and the interior of the vacuum collection container as described above. A collection container can then be inserted into the tube holder 800 and used for sample collection as described above via the non-patient puncture tip 462. In such further sample collection, both the vacuum collection container and the secondary chamber 427 are under negative pressure, and therefore both are drawn from the fluid inlet cannula. As described above, this action essentially establishes an equilibrium in the flashback chamber 426 so that the blood contained in the flashback chamber 426 can be removed (via the porous vent 910). It is prevented from being drawn toward the next chamber 427. The negative pressure in the vacuum collection container draws blood directly from the patient via the fluid inlet cannula 436 due to the close proximity and alignment of the fluid outlet cannula 452 and the fluid inlet cannula 426, as described above. Once such an additional vacuum collection container is filled with the desired amount of blood, the container is removed from the non-patient puncture tip 462 so that a sealable sleeve 461 covers the non-patient puncture tip 462 and In the closed state, fluid communication between the non-patient puncture tip 462 and the vacuum collection container is released.

  Once all of the desired blood sample has been drawn in this manner, the patient-side puncture tip 438 is removed from the patient's vasculature (ie, from the bloodstream), thereby opening the patient-side puncture tip 438. Expose to the outside environment. Since the only communication path between the housing interior and the external environment is through the patient-side puncture tip 438, the negative pressure established in the secondary chamber 427 relative to the external environment is within the flashback chamber 426. In addition, the blood contained in the fluid inlet cannula 436 is gently drawn toward and through the porous vent 910. Such retraction action causes blood contained within the fluid inlet cannula 436 to move from the patient puncture tip 438 toward the secondary chamber 427, and thereby from the patient puncture tip 438 of the fluid inlet cannula 436. Prevent blood from leaking. Such negative pressure in the secondary chamber 427 continues to have a gradual retraction action through the porous vent 910 for an extended period after removal of the patient-side puncture tip 438 from the patient. The remaining blood contained within the fluid inlet cannula 436 and flashback chamber 426 may be drawn through the porous vent 910 and / or into the secondary chamber 427. Thereafter, the needle assembly 410 can be properly disposed of in a known manner.

  Relative dimensional calculations, volumes and pressures apply to both illustrated and unillustrated embodiments of the present invention. As a result, the scope defined by the appended claims is not limited to the specific illustrated embodiments. Various other variations and modifications will be effected by those skilled in the art without departing from the scope and spirit of the invention. Such variations and modifications are intended to fall within the scope of the present invention.

Claims (5)

A method for operating a needle assembly comprising:
The needle assembly is
i) a needle housing defining the interior of the housing;
ii) a cannula having a first piercing tip extending from a first end of the needle housing;
iii) a second puncture tip extending from the second end of the needle housing, wherein the second puncture tip and the first puncture tip are in fluid communication with each other via the cannula. Two puncture tips;
iv) a porous vent positioned within the housing and separating the housing interior into a first chamber and a second chamber, the only communication path between the housing interior and the external environment being the first The cannula is in fluid communication with a first chamber and includes a hole for a passage of blood from the first chamber to the second chamber, such that the cannula is through a piercing tip. A porous vent, and blood contained in the first chamber is drawn into the vacuum collection container and air is drawn from the second chamber through the porous vent Establishing fluid communication between the second piercing tip and the vacuum collection container so that blood flows through the cannula to the first chamber and contacts the porous vent. 2 Chang Means for establishing a negative pressure against the external environment of the needle assembly in the bar,
When fluid communication between the second puncture tip and the vacuum collection container is released, the blood contained in the cannula is displaced away from the first puncture tip and displaced toward the second chamber. And a leakage prevention means is activated to draw blood toward the second chamber through the pores of the porous vent based on the negative pressure established in the second chamber.   The method of claim 1, wherein releasing the fluid communication comprises removing the vacuum collection container from the second puncture tip and sealing the second puncture tip from the external environment.   The needle assembly comprises a sealable sleeve extending around the second piercing tip, the sealable sleeve allowing fluid communication between the vacuum collection container and the second piercing tip; 3. The method of claim 2, wherein the method is displaceable to reseal when the vacuum collection container is removed from the second puncture tip.   After releasing the fluid communication between the second puncture tip and the vacuum collection container, the second is such that blood is drawn into the second vacuum collection container via the first puncture tip and the cannula. Further comprising establishing fluid communication between the puncture tip and the second vacuum collection container and subsequently releasing fluid communication between the second puncture tip and the second vacuum collection container. The method of claim 1, comprising: A method of operating a blood collection assembly for introducing a sample into a vacuum blood collection tube, comprising:
The blood collection assembly has a housing having a first needle tip, a second needle tip, and a flashback visualization chamber;
The needle assembly includes a housing having a porous vent positioned to separate the interior of the housing into a first chamber forming a flashback visualization chamber and a second chamber;
The first and second chambers are such that air is drawn from the second chamber through the porous vent and drawn into the vacuum blood collection tube with the sample, thereby creating a negative pressure in the second chamber. The negative pressure causes the sample to be drawn into the first chamber and contact the porous vent;
When the first needle tip is removed, the sample is drawn from the first chamber toward the second chamber with negative pressure in the second chamber, thereby preventing leakage of the sample from the first needle tip. A method of operating a blood collection assembly, wherein the leakage prevention means is operated to prevent.

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