Blood collection set with venting mechanism

Abstract

The blood collection set includes an IV needle assembly, a length of flexible plastic tubing extending from the IV needle assembly and a non-patient needle assembly. The set is formed with a venting mechanism that permits an outflow of air, while blocking an outflow of blood or other fluids. Thus, the venting mechanism enables air that had existed in interior portions of the blood collection set to be vented allowing for greater flash visualization on venous entry, and avoids the need to employ a discard tube.

Description

[0001] This application claims priority to U.S. Provisional Patent Application Ser. No. 60 / 576,140, which was filed on Jun. 2, 2004.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The subject invention relates to a blood collection set with self-venting features. [0004] 2. Description of the Related Art [0005] Phlebotomy procedures often are carried out using a blood collection set. A typical blood collection set includes an IV needle assembly with an IV cannula that has a proximal end, a sharply pointed distal end and a lumen extending between the ends. The needle assembly also includes a plastic IV hub with a proximal end, a distal end, and a passage extending between the ends. The proximal end of the IV cannula is mounted in the passage of the IV hub so that the lumen through the IV cannula communicates with the passage through the IV hub. The needle assembly may further include a shield for shielding the IV cannula after use and a packaging cover for safely c...

AI Technical Summary

Benefits of technology

[0013] The invention is a self-venting blood collection set with a self-venting mechanism that permits escape of air during use, and which, typically, also prevents an outflow of fluid, such as blood. As used herein, venting mechanism indicates one or more features or elements that provide venting of air, but which, typically, prevent fluid from passing through. Thus, air under venous pressure will be allowed to escape from the blood collection set through the mechanism until blood reaches the venting mechanism. The venting mechanism then will seal, or prevent blood flow through or around it, to prevent blood leakage and allow blood to be collected into evacuated collection tubes or into other appropriate blood collection receptacles. The invention thus provides good flash visualization, as well as the capability to provide a blood collection set that does not require a discard tube, without affecting accepted blood collection processes. A variety of venting mechanisms, venting media and venting locations are suitable, as set forth below. (As used herein, venting mechanism indicates the combination of elements, configurations, materials, etc. that provide the venting. As used herein, venting media indicates the actual element that vents the air, e.g., plug, coating, finish, etc.)

[0017] In one embodiment, the venting mechanism is located at or near the non-patient hub, e.g., in the hub itself near the distal end of the non-patient needle or in the tubing itself at a proximal end thereof. The venting mechanism thereby provides communication between the passage and the surrounding environment either through the passage itself or through the non-patient hub. Alternatively, wherein the venting mechanism is located in the tubing, any location along the tubing is possible.

[0019] In another embodiment, the venting mechanism is located beyond the non-patient cannula proximal end, which means that the air passes through the non-patient cannula proximal end from which blood is drawn, and then through the vent. Specifically, air is vented from the fluid passage and out of the non-patient cannula proximal end where it further flows through the space between needle exterior and multiple sample sleeve. The air then flows through the venting mechanism, which may be at the non-patient barb, the non-patient hub thread, the non-patient hub body, the multiple sample sleeve, or other location or combination of locations that are beyond the non-patient cannula proximal end. The collection tube, which is applied at the non-patient cannula proximal end, draws blood from only the fluid passage and not from the vent space. This embodiment thus enables blood to flow through the entire collection path for full tubing flash, eliminating the need for a discard tube and maintaining the desired blood to additive ratio. It also avoids the blood specimen coming in contact with the vent, which could potentially cause platelet activation, contamination or other undesirable result. It also avoids air being sucked back into the fluid passage when the evacuated tube is applied.

[0021] Another embodiment of this invention has a venting mechanism comprised of a unified non-patient hub that is at least partially constructed of porous material such as sintered plastic, ceramic or metal. The porous material can be arranged to provide venting of air either before that air enters the non-patient cannula, or after the air flows through the cannula, out the proximal end, and into the space between the cannula and a multiple sample sleeve. The porous material provides venting of the air but blocks leakage of the blood. In the typical embodiment, the porous material is hydrophobic. The porous material may further contain or be coated with materials that swell upon wetting to further contain the blood. Other venting methods are also possible. The internal passage wall's surface may be coated with a sealant to prevent contamination of the blood sample by the porous material. This embodiment enables blood to flow through the entire collection path for full tubing flash, and also enables elimination of the waste tube or variability in blood to additive ratio. Optionally, the hub can be permanently bonded to a tube holder obviating the need or inconvenience of threaded connections. Bonding to the holder may be accomplished by solvent, welding, heat, pressure or and other convenient means or combination thereof. Such an integrated device is highly efficient to manufacture, and promotes safe medical practice by having the holder be discarded with the needle.

[0022] In a further embodiment, the venting mechanism involves venting air through a side opening located somewhere along the fluid passage to the exterior, where the opening is covered by a venting material having a shape which mechanically holds the venting material in or on the opening. Preferably, the vent material is hydrophobic such that the surface tension also prevents leakage. The vent media material in this embodiment typically has an elastic property and shape such that spring energy holds the vent material onto the device. For example, it is possible to use a C-shaped vent in which distortion of the shape is required for the vent to stretch over the receiving structure on the hub. Once the vent is placed over the receiving structure, it is released and fully maintained in place using it's own resiliency and in absence of bonding materials such as epoxies, which could be disadvantageously absorbed into the vent. The vent mechanism of this embodiment could alternatively involve first compressing a vent material, placing the material into the opening, and releasing the vent material to expand into the opening. This embodiment enables efficient mass production.

Problems solved by technology

The reduced blood volume can be undesirable such as when it adversely affects the ratio of additive to blood within the tube.

This approach adds to the cost and time of the procedure and wastes blood.

This approach also wastes blood and can lead to contamination or accidental sticks depending upon the method of venting.

However, the initial movement of air into the evacuated tube is delayed until the evacuated tube is added onto the non patient needle.

Thus, a medical practitioner may have a delayed indication of venous or arterial access and may incorrectly assume that the blood vessel was not accessed properly.

Accordingly, the patient may be subjected to unnecessary trauma during a repeated attempt to access the targeted blood vessel.

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