Pneumatic vein inflation device
THE FIELD OF THE INVENTION 
     The instant invention relates to medical equipment for a treatment and/or testing procedure and, more particularly, to a medical device which facilitates the insertion of an intravenous needle. 
     THE BACKGROUND OF THE INVENTION 
     Intravenous feeding like several medical procedures requires insertion of a hollow needle in a vein to provide needed nutrients with medication and/or vitamins and is often initiated because the patient may be unconscious and/or is in cardiac arrest. A blood transfusion is another example of a medical procedure which requires insertion of a hollow needle in a vein. In many individuals a vein in the arm can be found easily for these purposes and can be inflated by applying manual pressure to the arm, but in a significant number of individuals, especially those in severe shock or cardiac arrest where their circulatory system may be in vascular collapse, the insertion of an intravenous needle will be significantly more difficult and time-consuming. 
     The measurement of blood pressure by a sphygmomanometer takes place by restricting the flow of blood using a pneumatic device comprising a rubber bladder covered by a long cloth sleeve and a rubber bulb connected to the bladder which can inflate it. This pneumatic device which is wrapped around the arm like a cuff during the measurement of blood pressure, restricts the flow of blood in the arm without injuring the individual. 
     It is an object of the instant invention to provide a pneumatic vein inflation device which holds back the flow of blood in a vein in an extremity, especially in an arm, and acts to inflate the vein for a medical testing and/or treatment procedure, by transposing a volume of blood from the upper arm to the lower arm. 
     It is also an object of the invention to provide a pneumatic vein inflation device which helps inflate a vein in an extremity, especially an arm, of an individual to initiate intravenous feeding of the individual. 
     It is another object of the invention to provide a pneumatic vein inflation device which helps inflate a vein in an extremity, especially an arm, of an individual to facilitate insertion of a hollow needle in the vein to draw blood or perform a blood transfusion. 
     It is a general object of the invention to provide a device which facilitates otherwise time-consuming and difficult intravenous procedures for individuals whose veins are difficult to find, toughened by old age or in vascular collapse. 
     THE SUMMARY OF THE INVENTION 
     According to the invention, the pneumatic vein inflation device for assisting in a medical testing and/or treatment procedure comprises a hard cylindrical tube, advantageously two inflatable ring-shaped bladders positioned in succession axially inside the hard cylindrical tube having a diameter somewhat less than the inner diameter of the hard cylindrical tube and a means for pressurization and relief of the inflatable bladders to and from a predetermined pressure and for distributing pressure between the inflatable bladders. The inflatable bladders are of such size that an extremity of an individual undergoing the medical testing and treatment procedure fits therein. 
     In one advantageous embodiment of the invention, there are two inflatable bladders one of which is significantly larger than the other, and the means for pressurization and relief comprises a hand-powered air pump and associated relief valve connected by a first air hose section to a three-way distribution valve, which in turn is connected by a second air hose section to the first smaller inflatable bladder, and by a third air hose section to the other larger inflatable bladder and a pressure gauge connected to the first air hose section. 
     An elastic jacket surrounding both inflatable bladders and the cylindrical tube can be provided to hold the inflatable bladders in place in the cylindrical tube. It can comprise an outer tubular sheath of substantially the same height as the inner tubular sheath, the opposite ends of the inner tubular sheath being attached to the corresponding opposite ends of the outer tubular sheath to form the jacket. The inner and outer sheath may be made of nylon. Advantageously, the inflatable bladders are made of an elastic material, for example rubber. 
     When there is difficulty finding a vein for insertion for a hollow needle for intravenous feeding or for another procedure, the pneumatic vein inflation device is slipped on the upper arm and the first smaller advantageously donut-like inflatable bladder is pressurized to a predetermined safe pressure with the hand pump while observing the pressure gauge so that the flow of blood in the vein is stopped temporarily. Then the distribution valve is turned, isolating the first inflatable bladder, and then the second longer bladder is pressurized until the vein in question is observable. Thus with the invention, a satisfactory intravenous feeding is possible. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     FIG. 1 is a schematic perspective view showing a pneumatic vein inflation device according to the instant invention in position on the arm of an individual requiring an intravenous medical procedure. 
     FIG. 2 is a partially perspective, partially cutaway cross sectional view of the vein inflation device of FIG. 1. 
     FIG. 3 is a detailed cross sectional view of the portion of the vein inflation device of FIG. 1 indicated with the dot-dashed circle 3 of FIG. 2. 
     FIG. 4 is a diagrammatic view of the vein inflation device of FIG. 1 showing a means for pressurizing its inflatable bladders with a pressure gauge, air pump, air hose and valves. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The embodiment of the pneumatic vein inflation device 10 shown in the drawing comprises a hard cylindrical tube 12, two internal inflatable ring-shaped bladders 14,16 positioned in succession axially inside the hard cylindrical tube 12, having a diameter DB less than the inner diameter of the hard cylindrical tube so that they just fit inside it, and a means for pressurization and relief 20 for pressurizing (and depressurizing) the inflatable bladders 14,16 to a predetermined pressure and for distributing pressure between the bladders. 
     Both internal inflatable bladders 14 and 16 have the same diameter DB and are made of rubber or some other inflatable material, but the first inflatable bladder 14 is considerably smaller in height than the other second inflatable bladder 16. The inflatable bladders 14 and 16 are held in position in the hard cylindrical tube 12 by an elastic jacket 18, advantageously made of nylon, which comprises an inner tubular sheath 18&#39; and an outer tubular sheath 18&#34; of substantially the same height attached to each other at opposite ends of the vein inflation device 10 to form an envelope enclosing the hard cylindrical tube 12 and the inflatable bladders 14 and 16. The size and elasticity of the inner tubular sheath 18&#39; and the outer tubular sheath 18&#34; are such that the inflatable bladders 14 and 16 are held in position when not inflated. This expandable jacket 18 helps keep the inflatable bladders 14,16 in position when they are being inflated. 
     The means for pressurization and relief 20 includes a hand powered air pump 22 and associate relief valve 23 for release of pressure similar to that used in the conventional blood pressure measuring device. This hand powered air pump 22 is connected to a distribution valve 24, which is essentially a three-way valve, by a first air hose section 26. The three-way distribution valve 24 is also connected on its other side to both inflatable bladders 14,16 by a second and third section of air hose 28,30. A pressure gauge 32 is connected to the first air hose section 26 between the distribution valve 24 and the air pump 22 and measures total pressure in the inflatable bladder 14 or 16 which the distribution valve 24 selects. This pressure gauge or pneumatic meter 32 is a conventional pressure measuring device. 
     The operation of this embodiment of the pneumatic vein inflation device according to the invention is as follows: 
     The vein inflation device 10 is slid on the upper arm 11 in the position shown in FIG. 1 with the inflatable bladders 14, 16 deflated. Then the air pump 22 is squeezed repeatedly with the relief valve 23 closed and the distribution valve 24 set so that the first donut-shaped inflatable bladder 14 is inflated to a predetermined pressure which can be determined from the pressure gauge 32. When that pressure is reached, the first inflatable bladder 14 is isolated by resetting the distribution valve 24. At this point the flow of blood back to the torso from the upper arm 11 should be stopped or greatly reduced (by appropriate selection of the final pressure). Then the larger inflatable bladder 16 is inflated to a point where the vein in the arm 11 is suitable for easy initiation of the desired intravenous procedure. Upon completion of that procedure, the device is deflated by opening the relief valve 23, and the distribution valve 24 selects the appropriate bladders 14, 16 in reverse order to that used in inflation. 
     In other embodiments the number of bladders used in the invention may be varied from one to several within the scope of the invention. 
     No specific dimensions for the inflatable bladders, the elastic jacket or the hard cylindrical tube have been provided because of the wide variation between individuals due to age, weight and/or gender. 
     LIST OF REFERENCE NUMBERS 
     10 pneumatic vein inflation device(the invention) 
     11 arm 
     12 hard cylindrical tube 
     14 first donut-shaped inflatable bladder 
     16 second inflatable bladder 
     18 elastic jacket 
     18&#39; inner tubular sheath 
     18&#34; outer tubular sheath 
     20 means for pressurization and relief 
     22 hand powered air pump 
     23 relief valve 
     24 distribution valve 
     26 first air hose section 
     28 second air hose section 
     30 third air hose section 
     32 pressure gauge 
     DB diameter of the inflatable bladders 
     It will be understood that each of the elements described above, or two or more together, may also find a useful application in other devices differing from the type of device described above. 
     The invention is not intended to be limited to the details provided above and it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of the prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.