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Home | Alpha Telephone | Domain Names | Web Hosting | Get Traffic | xrEvidence | xrSoccer United States Patent
VACUUM INDICATOR An apparatus for withdrawing blood from a body vessel of the type including a tube with a partial vacuum pressure therein sealed at an open end by a flexible stopper, a needle having a sharp end for penetrating a vessel, an interior blood carrying cavity, an opposite sharp end, and a sleeve attachable to the needle so that the opposite end of the needle extends into the sleeve and adapted for receiving the stopper so that, when the one needle end penetrates the vessel, the stopper moves within the sleeve toward the opposite needle end which punctures the stopper and causes the blood to be drawn through the interior of the needle into the tube. In order to avoid unnecessary damage to blood vessels from attempts to withdraw blood with tubes which have lost their partial vacuum pressure, a quantity of material such as hemoglobin having a color which varies with the pressure about it is disposed within the tube before it is evacuated. The material can be dry and painted on the tube walls or liquid. Other indicators include cytochrome, myoglobin, heme and leucobases. In a further embodiment, two objects which have different air resistances, so that in full or partial pressure they fall under the influence of gravity, are disposed within the tube.
Assistant Examiner: Recla; Henry J. Attorney, Agent or Firm: This is a division of application Ser. No. 228,687 filed Feb. 23, 1972, now U.S. Pat. No. 3,800,780. What is claimed is: 1. An apparatus for removing blood having a tube with at least partial vacuum pressure therein below atmospheric pressure and a needle connected to said tube with an end adapted for penetrating into a blood carrying body vessel and an interior blood transferring cavity so that, when said end has penetrated into a vessel, said cavity is in pneumatic connection with the interior of said tube and blood from that vessel is drawn through said cavity into the interior of said tube, the improvement comprising a quantity of hemoglobin painted on a portion of said tube, which has a color which varies as a function of the amount of oxygen about it, said material being within said tube for indicating by a change in color, a change in the amount of oxygen and the loss of said partial vacuum pressure. 2. An apparatus as in claim 1, wherein said apparatus further includes flexible means sealing an open end of said tube and a sleeve member with said needle attached to one end and receiving said flexible means at the other end and wherein said needle has an end, opposite said end adapted for penetrating said vessel, for puncturing said flexible means when a force is exerted on said tube to cause said penetrating end of said needle to penetrate said vessel and said puncturing end to puncture said flexible means as said sealing means moves toward said needle within said sleeve member. 3. An apparatus as in claim 1, wherein said tube is transparent. 4. A combination of an enclosed vessel having at least a partial vacuum below atmospheric pressure therein and a quantity of dry hemoglobin, which has a color which varies as a function of the amount of oxygen about it, said material being within said vessel and visible from the exterior thereof for indicating by a change in color a change in the amount of oxygen and accordingly a change in the pressure within said vessel. 5. A method of producing a vessel with at least a partial vacuum pressure below atmospheric pressure therein comprising the steps of: placing within said vessel a quantity of material which has a color which varies with the amount of oxygen about said material and accordingly the pressure about said material including painting a lacquer of hemoglobin on a portion of the walls of said vessel; and evacuating said vessel to said partial vacuum pressure. BRIEF DESCRIPTION OF THE PRIOR ART AND SUMMARY OF THE INVENTION The invention relates to an apparatus for removing blood of the type in which a hollow needle which is insertable into a blood-carrying vessel is in communication with a tube having a partial vacuum pressure therein so that when the needle penetrates into the blood-carrying vessel the blood is drawn through the hollow needle into the tube. The removal and analysis of blood is one of the most common and useful medical techniques now in use. Blood removal can be accomplished in any of a number of ways and a variety of devices are available on the market for that purpose. One of the most widely used devices includes a tube with a partial vacuum pressure therein which is sealed at its open end by a flexible stopper. This tube is usually constructed of glass, comes in a variety of sizes and has a sterilized interior for receiving blood samples. A disposable needle having two sharp ends and a hollow interior is attachable, for example, by threads to a plastic sleeve member which receives the stopper in the tube so that the stopper and tube can move within the sleeve toward one sharp end of the needle which protrudes into the sleeve toward the stopper. When the sharp end of the needle protruding from the plastic sleeve is inserted into a body vessel a drop of blood will normally appear in the plastic sleeve. At this time, the tube can be pushed within the sleeve toward the needle so that the sharp end of the needle penetrates the rubber stopper and accordingly communicates with the interior of the tube which is at a partial vacuum with the interior of the blood-carrying vessel. Because of the pressure differential, the blood in this vessel is drawn through the hollow disposable needle and into the glass tube until a sufficient quantity of blood is located therein. At that time, the individual withdrawing the blood has no way of ascertaining whether the tube still contains a partial vacuum pressure. The tubes are, of course, normally evacuated at the manufacturer's facilities prior to shipment to the location where blood is withdrawn. That shipment may involve considerable rough handling. Further, there is frequently a delay of a considerable amount of time which may be months or even years between when the tubes are evacuated and when they are used for withdrawing blood. The result is that frequently the partial pressure within the tube has been lost at the time in which the device is used. If there is atmospheric pressure within the tube when the needle is inserted into the blood vessel, of course, blood is not drawn back into the vacuum tube. The user of the device has no way knowing whether the failure to draw blood is because of the absence of a partial vacuum pressure in the tube or because he has failed to insert the needle in the vessel. Normally, the individual using the device will make several attempts to insert the needle into the vessel before assuming that there is atmospheric pressure within the tube; the result is unnecessary and frequently extensive damage to the blood carrying vessel. Since, in connection with many medical treatments, blood must be withdrawn many times daily, even an occasional use of a tube without vacuum pressure is painful and damaging to the patient. The present invention relates to a method and apparatus whereby an indicator is placed in the tube before evacuation. This indicator has a visual characteristic, preferably color, which varies as a function of the partial pressure therein so that the loss of that partial pressure can easily be seen by the technician before he attempts to remove the blood sample. One of the indicators which is believed to be particularly advantageous is hemoglobin which is a substance normally produced by the body and which is responsible for the difference in color between arterial and veinous blood. The indicating material can be painted as a dry laquer on the sides of the vessel or alternately a small quantity of a liquid material, such as hemoglobin can be simply disposed in the indicating tube. Other materials, believed suitable as indicators and which will change color when the vacuum pressure is lost, include different types of cytochrome, myoglobin, heme and various leucobases. It is, of course, important that any indicator in the vacuum tube not interfere with any particular test which is to be carried out and an appropriate indicator is preferably chosen at least partly on that basis. Such an indicator can, of course, be used to indicate absence or presence of a partial vacuum in any device and while the present invention finds particular utility in connection with the apparatus described above, there is no intention to limit the invention to this particular device for withdrawing blood. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an exploded view of a device for drawing blood from a body vessel including a tube having a partial vacuum pressure therein and an indicator painted on a portion of the interior tube walls for indicating a loss of that partial vacuum pressure. FIG. 2 shows a tube which can be used in connection with the blood withdrawing device of FIG. 1 whereby a liquid indicator is disposed within the tube for indicating the absence or presence of a partial vacuum pressure. FIG. 3 illustrates the device of FIG. 1, assembled and in use with the sharp end of the needle, which protrudes into the sleeve, puncturing the rubber stopper and communicating with the interior of the tube for withdrawing blood from the body vessel. FIG. 4 illustrates another embodiment with two objects having different air resistances so that at full or partial pressure they fall at different rates under gravity. FIG. 5 illustrates another embodiment with a vaned object which spins when falling in full or partial pressure. FIG. 6 illustrates a perspective view of the vaned object of FIG. 5. DETAILED DESCRIPTION OF THE DRAWINGS Reference is now made to FIG. 1, which shows an exploded view of an apparatus for withdrawing blood as discussed briefly above. This apparatus includes a disposable needle 20 which has sharp ends 22 and 24 and a hollow interior passage 26 connecting ends 22 and 24. Disposable needle 20 is attachable to a sleeve member 28 which is preferably plastic with threads 30 of needle 20 mating with threads 32 of sleeve 28 so that end 24 protrudes into the interior of the sleeve 28 as illustrated in FIG. 3. Sleeve 28 is preferably reusable. Tube 34 is preferably constructed of glass and after sterilization is evacuated to a partial vacuum pressure sufficient to withdraw a satisfactory quantity of blood in the fashion described above. After evacuation, tube 34 is sealed by the flexible stopper 36 which may be of rubber or other suitable material. Sleeve 28 and stopper 36 mate so that stopper 36 of the tube 34 are moveable within sleeve 28 in a substantially airtight connection toward and away from the protruding end 24 of disposable needle 20. As illustrated in FIG. 3, when needle 20, sleeve 28, and tube 34 are assembled and the end 22 of the needle 20 inserted into the body blood vessel, stopper 36 and tube 34 can be moved toward end 24 of needle 20 so that end 24 punctures the flexible member and communicates the interior of tube 34 which has been evacuated to a partial vacuum pressure with the interior of the blood vessel. Normally, such puncturing would be accomplished after a drop of blood has appeared within the interior of sleeve 28 indicating that the vessel had been correctly penetrated. The difference in pressure between the interior of tube 34 and the vessel penetrated by needle 20 causes blood to be drawn into the tube 34. When a satisfactory amount of blood is disposed into tube 34, end 22 of needle 20 is withdrawn from the blood vessel. Needle 20 is then detached from sleeve 28 and discarded, while sleeve 28 is reused. Stopper 36 and tube 34 can then be withdrawn from sleeve 28 with the opening created by the needle 26 being sealed so that the blood is kept sealed within tube 34 until just previous to analysis by the laboratory, thus minimizing the danger of contamination. After analysis tube 34 and stopper 36 can then be discarded. As discussed above, it is of considerable assistance to the people using the device and of considerable advantage to the individual whose blood is being withdrawn if the presence or absence of a partial vacuum pressure within tube 34 can be easily ascertained previous to an attempt to withdraw blood. In the embodiment illustrated in FIG. 1, a quantity of material 40, which in this embodiment is painted dry on a portion of the interior walls comprising tube 34, serves as that indicator, changing color when the vacuum pressure is lost in tube 34. As discussed above this can easily happen during the considerable time interval and rough handling which takes place between the evacuation and use. One such material which is believed to be particularly advantageous is hemoglobin which is the blood substance responsible for the difference in color between veinous and arterial blood. In a partial vacuum pressure, the hemoglobin will appear as a dark red. However, should the vacuum pressure be lost and the quantity of oxygen within tube 34 rise, some of that oxygen will react with the hemoglobin causing the color to change to a bright red. Since, normally, the loss of pressure will not occur immediately before use of the device, it is not important that the indicator 40 be quick acting. There are a number of other possible substances which can satisfactorily serve as indicators. These substances include different types of cytochrome, myoglobin, heme and various leucobases. It is important, of course, that any particular indicator being used not interfere with the particular analysis which is being carried out, and the indicator is preferably chosen at least partially for that reason. As an alternative to painting the dry indicator on the side of the tube 34 before it is evacuated, a quantity of liquid indicator 50 can be disposed in tube 34 as illustrated in FIG. 2, provided of course that the indicator remains liquid at the chosen partial vacuum pressure. Any other way of disposing a suitable indicator into tube 34 so that the change in color can be easily and quickly observed from the exterior of transparent glass tube 34 can, of course, be employed. Reference is now made to FIGS. 4-6, which illustrate further embodiments of the invention in which the presence or absence of a vacuum can be visually determined by observing the free fall by gravity of one or more objects within the tube. In FIG. 4, a first object 50, such as a small plastic ball, and a second object 52 such as a bird feather or featherlike object are disposed within tube 54 which is sealed by stopper 56. It is well known that in a vacuum all objects fall under the influence of gravity at the same rate. However, in a full or substantial pressure the air resistance of an object also bears on its fall rates. Thus, in air, feathers fall at a slower rate than spherical balls. This phenomenon can be used to simply determine a leakage into tube 54 by simply inverting the tube and observing the fall of objects 50 and 52. If there is a substantial pressure within tube 54, then object 52 because of its greater surface area will fall at a markedly lower rate than object 50. Objects 50 and 52 can be constructed of any suitable material which will not break tube 54 and which will not affect any substance drawn into tube 54. A soft plastic is believed satisfactory. In the embodiment of FIGS. 5 and 6, a single object 60 having a pair of vanes 62 and 64 is disposed within tube 66 which is sealed by stopper 68. Vanes 62 and 64 are disposed at a slight angle to the horizontal with most of the mass of object 60 below the vanes so that when object 60 falls through the air it spins like helicopter blades. In a vacuum, of course, no spinning takes place so that the presence or absence of a vacuum can be readily determined by observing the fall of object 60 within tube 66. Object 60 can also be made of any suitable material which does not affect a substance drawn into tube 66 and which will not damage tube 66 in its fall. While the embodiments of the invention described above are related to a device for withdrawing blood, this invention can, of course, be used for indicating the presence or absence of a partial vacuum pressure in any container in which the changing color can be observed from the exterior thereof. Any other changes and modifications in the above embodiments of the invention can, of course, be made without parting from the scope of the invention, and that scope is intended to be limited only by the scope of the appended claims. For U.S. patent law, rules, and procedures see MPEP. Disclaimer. Information presented on this page while believed to be reliable, is provided "as is" with no warranties of its accuracy or timeliness. For legal advice seek help of a licensed professional. |