Surgery – Truss – Pad
Patent
1989-07-10
1990-11-27
Hafer, Robert A.
Surgery
Truss
Pad
128763, 128764, 604192, A61B 500
Patent
active
049728431
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to equipment suited for taking fluid samples from patients. The equipment includes a fluid sampling device which comprises front and rear needles which face away from one another and with which the pointed end of the front needle is configured for insertion into a blood vessel of a patient and the pointed end of the rear needle is configured for insertion into a sealing stopper located in a vacuum-type test tube which is capable of being inserted partially into the sampling device, and which sampling device incorporates in the space between the mutually opposing ends of the two needles a flow regulating valve means which is operative to regulate the flow of sample through the needles, said flow regulating valve means being spring biassed towards a closed position and capable of being depressed towards an open position by means of a force which acts on an actuator means and which is greater than the force represented by the spring bias.
One such sample taking device is known from U.S. Pat. No. 4,326,541. This known sampling device affords several important advantages in comparison with the technique most often used in health care when taking venous samples of body fluid. The standard sample taking device in current use includes a carrier which supports two puncture needles. The needles project from the carrier in two mutually opposite directions and are in direct communication with each other. When using this known device, one of the needles is inserted into a vein or like blood vessel and a stoppered vacuum-type test tube is then pushed axially onto the other needle. When the needle has penetrated the stopper, the desired amount of blood is drawn from the vein into the tube through the medium of the partial vacuum prevailing therein.
One drawback with this known method is that the vacuum tube cannot be pushed onto its associated needle until the other needle has been inserted into a vein, or like blood vessel, since otherwise the partial vacuum in the tube would be equalized and no suction would be obtained when subsequently attempting to take a sample. Furthermore, a certain amount of force is required to fit the test tube to the rear needle when the front needle is inserted, and consequently there is a danger that the front needle will be pushed further into the vein and possibly out through the opposite wall thereof, which puts the patient at serious risk. In addition, the small needle movements which are inevitable when fitting the vacuum tube to an inserted needle may be painful to the patient.
Another drawback with this known device is that when several tubes are to be filled with sample liquid sequentially from one and the same vein, sample liquid is liable to spill during the interchange of tubes. To overcome this, the rear needle, which is intended to pierce the sealing stoppers of respective tubes, is fitted with a check valve in the form of a rubber hose. The seal afforded by this valve, however, is impaired by the repeated puncturing of consecutive stoppers, with the subsequent risk of sample fluid escaping to the surroundings. This escape of fluid constitutes a serious problem with respect to the risk of spreading infection.
These problems are solved by means of the fluid sampling device described in the aforesaid U.S. Pat. No. 4,326,541. This known device includes a flow regulator which normally blocks the passageway between the two needles and which when in a closed position prevents the partial vacuum prevailing in a vacuum tube from being equalized, thereby enabling the vacuum tube to be fitted onto one needle before inserting the other needle into a vein or like vessel. Thus, a vein can be punctured with a vacuum tube attached to the rear needle, thereby obviating the need to fit the vacuum tube at a later stage and therewith avoiding the risk of transection of the vein and also of causing the front needle to move subsequent to its insertion. This risk is also reduced still further by the fact that the force required to operate the check valve acts perpendicu
REFERENCES:
patent: 4326541 (1982-04-01), Eckels
patent: 4409991 (1983-10-01), Eldridge
patent: 4418703 (1983-12-01), Hoch et al.
patent: 4592744 (1986-06-01), Jagger et al.
patent: 4731059 (1989-03-01), Wanderer et al.
patent: 4791938 (1988-12-01), Van Valkenburg
patent: 4841985 (1989-06-01), Wanamaker
patent: 4850734 (1989-07-01), Diaz-Ramos
patent: 4886072 (1989-12-01), Percarpio et al.
Hafer Robert A.
Owens Kerry
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