The use of evacuated tubes for the collection of blood samples is well known. Conventional blood collection devices include a cylindrical container or blood collection tube, a blood collection tube holder and a double ended needle. The blood collection tube includes a closed bottom end and an open top end which is sealed by a needle-pierceable stopper or closure. The blood collection tube holder includes an elongate barrel section, a proximal finger flange and a distal needle hub mounting section.
In a conventional blood collection device, the evacuated blood collection tube is removably mounted in the elongate tubular blood collection tube holder. The distal end of the blood collection tube holder includes a threaded hub section which releaseably engages the threaded hub of the double-ended needle. The needle of the conventional blood collection device is typically straight and includes distal and proximal needle sections wherein the distal section of the needle is designed to pierce the vein of the patient and the proximal section of the needle is designed to pierce the stopper of the evacuate collection tube.
Typically, blood is withdrawn from a patient by first puncturing a vein with one end of the double-ended needle and then, while firmly holding the blood collection tube holder, pushing the needle pierceable stopper of the blood collection tube against the other end of the needle until the stopper is pierced. After the desired volume of blood is drawn from the patient's vein into the blood collection tube, the needle is withdrawn from the patient. In the conventional blood collection device, the needle is then removed from the blood collection tub holder and discarded. A new needle may then be threaded onto the blood collection tube holder and the device is used to obtain another blood sample from another patient.
With the onset of AIDS and other infectious diseases, a variety of devices have been designed to decrease the likelihood that a health care worker will be infected by accidental contact with an infected needle. Even if the health care worker does not actually contract the disease from the infected needle, a large amount of time and money is spent on testing and counseling the health care worker every time the health care worker is inadvertently stuck by a potentially infectious needle.
U.S. Pat. No. 4,758,231, issued to Haber et. al. on July 19, 1988, discloses one approach to protecting the health care worker from accidental needle sticks. In the Haber device, a protective shield surrounds the blood collection tube holder while blood is being drawn from the patient. Once the final blood sample has been obtained, the shield is moved distally along the blood collection tube holder to an extended position wherein the distal end of the standard blood collection needle is covered by the protective shield.
Another approach is generally disclosed in U.S. Pat. No. 4,782,841 issued to Lopez on Nov. 8, 1988 and U.S. Pat. No. 4,731,059 issued to Wanderer et. al. on Mar. 15, 1988. In the Lopez and Wanderer devices, an elongated blood collection needle is used in combination with a blood collection tube holder and protective sleeve. The protective sleeve of the respective devices is mounted directly on the elongate distal section of the needle. In the retracted position, the protective shield exposes the distal end of the needle. In the extended position, the protective shield is moved distally along the needle shaft until the protective shield covers the distal end of the needle whereupon the proximal end of the protective sleeve engages a locking mechanism mounted on the needle shaft.
Although the above described devices satisfy the general requirement that the distal end of the needle be protected by a movable shield, the cost of molding and assembling these devices would result in a final product which is not affordable for many hospitals. Additionally, the protective shield of the Haber device increases the outer circumference of the blood collection assembly so that the health care worker may have difficulty carrying multiple blood collection devices on their tray and the blood collection tube holder is not reusable. The devices disclosed in the Lopez and Wanderer patents require the use of an unusually long needle in order to accommodate mounting the protective shield directly on the distal section of the needle. This dramatically increases the cost of producing a device as disclosed in the respective patents. All of the above described patents also require the health care worker to use both hands in order to extend the protective shield. In the Lopez and Wanderer patents, one of the hands of the health care worker must be placed unacceptably close to the potentially infectious distal end of the needle in order to move the protective shield to the extended position.
U.S. Pat. No. 3,326,206 ('206 patent) issued to Barr et al on June 20, 1967 and U.S. Pat. No. 3,520,292 ('292 patent) issued to Barr et al on July 4, 1970 are generally relevant to the present invention for the disclosure of a blood sampling device having a curved needle generally of the type contemplated by the present invention. The device disclosed in the '206 patent is designed to allow the needle to be mounted in or removed from a needle holder without touching the needle. The blood collection device disclosed in this patent includes a slide element which contacts and retains the needle in the needle holder while the blood collection device is in use and wherein the slide element is movable to allow for the removal of the needle from the needle holder. The device illustrated in the '206 patent provides no protection against accidental needle sticks and may actually contribute to the incidence of potentially dangerous needle sticks by providing a device wherein the entire blood collection needle is designed to be removable from the needle holder. The blood collection device illustrated in the '292 patent utilizes a curved needle and a modified blood collection tube holder. The '292 patent is directed to providing a blood collection device having a removable distal end cap and a movable protective diaphragm on the proximal end of the modified blood collection tube holder to provide a blood collection device which is maintained in a sterile condition during storage and transport. As with the '206 patent, the '292 patent provides no protection against accidental needle sticks and requires the use of a modified, non-reusable blood collection tube holder.