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Field of the Invention
The present invention relates generally to medical diagnostic testing devices where suction is applied to a liquid body material to draw it to a retrieval site, and more particularly, to a hematocrit pipette filling device configured to lessen the filling time of the tube.
Description of the Prior Art:
Because two of the most commonly ordered blood tests are hematocrit (Ht or HCT) and hemoglobin (Hb) measurements, considerable time could be saved by allowing clinicians to perform these tests more quickly and conveniently. The hematocrit value quantifies the percentage of red blood cells out of the total blood volume. The hemoglobin test measures the weight of hemoglobin in 100 milliliters of whole blood, with hemoglobin being the iron-containing globular protein component of a red blood cell that transports oxygen from the lungs to the cells. Hematocrit and hemoglobin measurements assist in the diagnosis of anemia (a shortage of red blood cells), polycythemia (an overproduction of red blood cells), internal bleeding, fluid retention, hypoxia, dengue shock syndrome, and other diseases and conditions. Currently blood for the hematocrit and hemoglobin tests are obtained by filling a small hematocrit tube (also called a capillary tube or micro-hematocrit tube) with blood by capillary action. Commonly, especially in infants and young children, the blood to fill the hematocrit tube is obtained by pricking the finger or heel of the patient with a quick jab of a lancet and allowing the drop of blood that oozes out to be drawn up into the hematocrit tube by capillary action. This procedure to obtain samples of blood in the hematocrit tube is slow and tedious because the blood is constantly coagulating. This leads to administering multiple punctures to the patient, which can cause infection, hitting a nerve or a bone, as well as unnecessary pain and suffering. Elderly patients because of a rapid coagulation tendency generally, often must have the test administered multiple times. With the risk of lowered immune capacity because of their age and the inherent risks mentioned due to multiple administrations of the test, clearly a more proficient method for obtaining such samples is necessary. It should also be noted that a certain skill level is required to administer this test properly. Air bubbles can easily form in the tube, if not administered properly, and this is often not recognized by the clinician administering the test. This can lead to either erroneous results or a missed diagnosis. Overall it is about the efficiency of application for accurate readings and test results, coupled with reducing pain levels in patients, which mitigates applying multiple applications of the test, and thus reducing expenditures for hospitals and clinics that this present invention addresses. If a syringe or vacuum blood collection tube of venous blood that has been collected from the patient by venipuncture is available, the hematocrit tube may be filled by capillary action out of it. After the hematocrit tube is filled, the end is sealed with sealing wax, putty, clay, flame, or a cap, and it is placed into a centrifuge to spin and separate the blood into layers, or it can be tested with an automated analyzer. When filling the hematocrit tube by capillary action, significant time may be required as the blood is drawn slowly into the tube, necessitating extra staff time. In addition to the aforementioned considerations above it would be advantageous to have a device that, while remaining safe and economical, would enable the hematocrit tube to be filled efficiently at a faster rate of speed, thereby reducing the time required, both for the patient and the clinician. Furthermore, it would be beneficial to provide a device that would allow the hematocrit tube to fill more quickly without modifying the size, shape, and design of the standard hematocrit tube itself, so that no change is needed for the standard centrifuges and automated analyzers that typically perform the hematocrit and hemoglobin tests. Although hematocrit tubes have evolved over the years, the changes have been in the materials used to make the hematocrit tubes and the methods of performing the hematocrit and hemoglobin tests, but have not been in decreasing the time required to fill the tube, nor the efficiency of application of such tests.
Summary of the Invention
The present invention is directed to a safe, efficient, and inexpensive hematocrit pipette filling device that uses suction to draw blood into the tube and that augments capillary action to fill the tube more quickly and efficiently. The hematocrit pipette filling device includes a squeeze bulb, a one-way check valve, a relief valve assembly, as well as a sheath with an internal passageway containing a collar configured to both support, and removably engage a standard hematocrit tube. The relief valve, disposed between the sheath and the squeeze bulb, is configured with an inlet port, an outlet port, and an actuator. The method of use includes inserting a hematocrit tube into the collar of the sheath and manually expelling air from the squeeze bulb through the check valve to create suction. The hematocrit tube is placed in position near a source of blood. The relief valve actuator is manually activated to initiate suction, whereby the pressure differential assists the capillary action in filling the hematocrit tube more quickly and efficiently.
Brief Description of the Drawings:
The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the invention, where like designations denote like elements, and in which: FIG. 1 is a cross-sectional view showing a first preferred embodiment of the hematocrit pipette filling device of the present invention.
Detailed Description of Invention:
Referring now to FIG. 1, a hematocrit pipette filling device, shown generally as reference number 10, is illustrated in accordance with a preferred embodiment of the present invention. The hematocrit pipette filling device 10 in general includes a squeeze bulb 12, a one-way check valve 16, a relief valve assembly 20, and a sheath 15 having an internal passageway 25 containing a collar 31 configured to support, seal, and removably engage a standard hematocrit tube. The squeeze bulb 12 includes 2 ports, a proximal opening 13 and a distal opening 14. A one-way check valve 16 is securely disposed in distal opening 14 and is configured to allow air to be manually expelled from squeeze bulb 12 through check valve 16. Although shown as a spring-loaded ball-type check valve, any one-way valve as is known in the art is within the scope of the invention. Relief valve assembly 20 is securely disposed in proximal opening 13 of squeeze bulb 12. Relief valve assembly 20 includes a valve housing 17, a valve inlet port 23, a valve outlet port 27, a manually controlled actuator 22, and a piston 24. Actuator 22 is integrally connected with piston 24 by actuator shaft 18, and this entire rigid assembly is moveable within housing 17. O-ring 28, generally a round elastomeric ring, ensures a fluid-tight seal between the lower section of housing 17 and piston 24. O-ring 19 ensures a fluid-tight seal between the upper section of housing 17 and shaft 18 of piston 24. Shaft 18 of piston 24 is movable relative to o-ring 19. Piston 24 is movable relative to o-ring 28 and is configured to vary flow between valve inlet port 23 and valve outlet port 27. In the initial closed position, piston 24 prevents fluid movement. When activated by actuator 22, piston 24 moves down into a recess 21 of the lower section of valve housing 17 to allow fluid movement from hematocrit tube 30, through internal passageway 25, into valve inlet port 23, around actuator shaft 18, through valve outlet port 27 and into squeeze bulb 12. Spring assembly 26 is mounted in housing 17 and configured to apply a force to piston 24 tending to urge piston 24 into a closed position. Sheath 15 is formed as an integral extension of relief valve assembly 20, with internal passageway 25 in fluid communication with valve inlet port 23. Collar 31 is disposed within the proximal end of sheath 15. Collar 31, preferably formed of a somewhat flexible or pliable material configured to allow for easy insertion and removal of hematocrit tube 30. It is also configured to support the inserted hematocrit tube 30 when the hematocrit pipette filling device 10 is in use. The method of use of hematocrit pipette filling device 10 includes inserting the standard hematocrit tube 30 into collar 31, and then manually expelling air from squeeze bulb 12 through check valve 16 to create a vacuum. The hematocrit pipette filling device 10 with attached hematocrit tube 30 is placed in position near a source of blood, with the end of hematocrit tube 30 touching the blood. The blood source can be capillary blood which will be taken directly taken from the patientís body (a finger stick having been performed just before starting this method), or the blood source may be venous blood in a blood collection tube or syringe that has previously been collected from the patient by venipuncture. The relief valve actuator 20 is manually activated, moving piston 24 to allow the pressure differential caused by bulb 12 to draw the blood into hematocrit tube 30, assisting the capillary action and filling the hematocrit tube more quickly and efficiently. When the hematocrit tube 30 is filled to the desired amount it is manually detached from the hematocrit pipette filling device, and then the desired medical test is preformed on the blood-filled hematocrit tube 30. Hematocrit pipette filling device 10 may be manufactured to be disposable or reusable. Other valves, as are known in the art, may be utilized for relief valve 20 without departing from the invention. Since many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.
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The Nasogastric Tube
Detector for Heat Tapes and Portable Heaters
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Inventor: Terra Projects, Inc.
E-mail: [email protected]
Phone: (772) 621-8187
Cell: (678) 794-5657