Abstract:
One embodiment of a blood transfusion device includes a drip chamber (10) comprising a bottom outlet (113); a filter (40) fixedly disposed in the drip chamber (10); and a float regulator (20) moveably disposed in the drip chamber (10) under the filter (40). the float regulator (20) comprising an inverted upper cup (21) including a top projection (212), a lower cup (22) secured to the upper cup (21), and a suction cup (23) secured to an underside of the lower cup (22). An inner diameter of the upper cup (21) is greater than an outer diameter of the lower cup (22). The projection (212) contacts an underside of the filter (40) when blood from a blood bag (90) sufficiently fills the drip chamber (10). The suction cup (23) falls to permanently close the outlet (113) when blood in the drip chamber (10) completely drains.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The invention relates to blood transfusion devices and more particularly to a safety blood transfusion device which can be disposed after use. 
         [0003]    2. Description of Related Art 
         [0004]    U. S. Pat. No. 6,569,116 to Wang is directed to an intravenous (IV) flow controlling device comprising a flexible open container having a specific gravity less than one and an outer diameter smaller than that of the drip chamber, the container including a spherical bottom portion thinner than the shell upper portion thereof; a first plastic tube coupled to the bottom of the container being in communication with the exit; a flexible reservoir having one end coupled to the first tube; and a second plastic tube coupled to the other end of the reservoir being in communication therewith. The container is submerged as fluid filled in the drip chamber. Fluid flows through the exit, the first plastic tube, the reservoir, and the second plastic tube to cause the container to fall, thereby stopping fluid exiting when the bottom portion of the container closes the exit and fluid in the drip chamber is used up. The reservoir is capable of being squeezed to force solution stored in the reservoir to reverse flow through the first tube to disengage the container from the exit. The device functions normally when solution is used up, abnormal solution dropping, drip chamber shaken, or drip chamber slanted. 
         [0005]    The patent works well when the source is saline. However, it is no appropriate for blood transfusion as detailed below. In blood transfusion, red cells, plasma and platelets are separated into different containers and stored in appropriate conditions so that their use can be adapted to a patient&#39;s specific needs. Red cells work as oxygen transporters, plasma is used as a supplement of coagulation factors, and platelets are transfused when their number is very scarce or their function severely impaired. Platelets in the blood may coagulate to form clots which can adversely block the small bores of the tubes. This in turn can cause the IV flow controlling device to fail. Thus, the need for improvement still exists. 
       SUMMARY OF THE INVENTION 
       [0006]    It is therefore one object of the invention to provide a disposable safety blood transfusion device after use after considering the high viscosity of blood being liable to block the outlet of a typical drip chamber for IV infusion. Moreover, blood is prevented from entering a drip chamber of the blood transfusion device again via the outlet. 
         [0007]    One aspect of the invention is to provide a disposable safety blood transfusion device in which contact between a filter and a float regulator is greatly decreased so as to prevent them from being adhered together. Otherwise, it may be uneasily separated due to the high viscosity of the blood after blood transfusion. 
         [0008]    Another aspect of the invention is to provide a disposable safety blood transfusion device in which an outlet of a drip chamber is permanently closed by a suction cup after use. Thus, a second blood supply to the drip chamber via a blood bag cannot disengage the suction cup from the outlet even when blood accumulates in the drip chamber. Therefore, the blood transfusion device as well as the blood bag can be discarded. 
         [0009]    By utilizing the invention, a number of advantages can be obtained as follows: 
         [0010]    An inner diameter of an upper cup is slightly greater than an outer diameter of a lower cup and a float regulator is permitted to float between an outlet of a drip chamber and a filter in the drip chamber as blood fills the drip chamber from a blood bag. 
         [0011]    Top of a float regulator is shaped as a cross, a curve, or any of other protrusions so as to effect a point contact rather than an area contact with a filter thereabove. Advantageously, it can prevent the float regulator from being uneasily disengaged from the filter once engaging because the viscosity of blood is higher than that of saline for IV infusion. It in turn can decrease the adherence of the float regulator to the filter. It is understood that it may malfunction the blood transfusion device if the float regulator and the filter become hard to separate after engaging. 
         [0012]    A suction cup has a thicker sharp central portion and secured to a lower portion of a connector of a lower cup. The suction cup may permanently close the outlet of the drip chamber after use. Thus, a second blood supply to the drip chamber via a blood bag cannot disengage the suction cup from the outlet even when blood accumulates in the drip chamber. Therefore, the blood transfusion device as well as the blood bag can be discarded. 
         [0013]    The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is an exploded view of a float regulator of a drip chamber for a blood transfusion device according to a first preferred embodiment of the invention; 
           [0015]      FIG. 1A  is a longitudinal sectional view of the assembled float regulator of  FIG. 1 ; 
           [0016]      FIG. 2  is an exploded view of a float regulator of a drip chamber for a blood transfusion device according to a second preferred embodiment of the invention; 
           [0017]      FIG. 2A  is a longitudinal sectional view of the assembled float regulator of  FIG. 2 ; 
           [0018]      FIG. 3  is an exploded view of a blood transfusion device according to the first preferred embodiment of the invention and a blood bag to be assembled therewith; 
           [0019]      FIG. 4  is a perspective view of the assembled blood transfusion device and the blood bag; 
           [0020]      FIG. 5  is a longitudinal sectional view of the drip chamber and the blood bag of  FIG. 4  where blood begins to flow into the drip chamber for blood transfusion; 
           [0021]      FIG. 6  is a longitudinal sectional view of the drip chamber of  FIG. 5  where blood continues to flow into the drip chamber for blood transfusion; 
           [0022]      FIG. 7  is a view similar to  FIG. 6  where blood stops flowing at the end of blood transfusion; and 
           [0023]      FIG. 8  is a longitudinal sectional view showing an inversion of the components shown in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Referring to  FIGS. 1 and 1A , a float regulator  20  of a drip chamber for a blood transfusion device in accordance with a first preferred embodiment of the invention comprises the following components as discussed in detail below. 
         [0025]    The float regulator  20  comprises an inverted cylindrical upper cup  21  including a cross shaped projection  212  on a top center, and a peg  211  extending downward from a bottom center directly under the projection  212 ; a cylindrical lower cup  22  including a hollow connector  221  through a bottom center for complimentarily securing to the peg  211 ; and a suction cup  23  having a thicker sharp central portion and secured to a lower portion of the connector  221 . It is noted that the projection  212  may have other shapes in other preferred embodiments. An inner diameter of the upper cup  21  is slightly greater than an outer diameter of the lower cup  22 . 
         [0026]    Referring to  FIGS. 2 and 2A , a float regulator  20 A of a drip chamber for a blood transfusion device in accordance with a second preferred embodiment of the invention comprises the following components as discussed in detail below. 
         [0027]    The float regulator  20 A comprises an inverted substantially half spherical upper cup  21 A including a curved top  212 A and a peg  211 A extending downward from a bottom center; a lower cup  22  including a hollow connector  221  through a bottom center for complimentarily securing to the peg  211 A; and a suction cup  23  secured to a lower portion of the connector  221 . An inner diameter of the upper cup  21 A is slightly greater than an outer diameter of the lower cup  22 . 
         [0028]    Referring to  FIGS. 3 to 8 , a blood transfusion device in accordance with a first preferred embodiment of the invention comprises the following components as discussed in detail below. 
         [0029]    A drip chamber  10  comprises a rigid transparent cylindrical casing  11  slightly tapered toward bottom, an annular first flange  111  proximate to a top open end, an annular second flange  112  under the first flange  111 , and a cylindrical outlet  113  extending downward from a bottom center. 
         [0030]    A pointed member  30  is adapted to pierce through a fixed bottom plug  91  of a blood bag  90  and mount on top of the drip chamber  10  by snappingly securing to the first flange  111 . A needle  80  is adapted to pierce through the plug  91  to supply air into blood L stored in the blood bag  90 . 
         [0031]    A cylindrical filter  40  comprises a top mounting member  41  snappingly secured to the second flange  112 , a bottom support  42 , two opposite posts  44  provided between the mounting member  41  and the support  42 , and a mesh structure  44  having a great number of closely-spaced holes, the mesh structure  44  disposed between the mounting member  41  and the support  42  with the posts  44  being disposed on the outer surface of the mesh structure  44 . The filter  40  is disposed in the drip chamber  10  under the pointed member  30 . The filter  40  is fixedly disposed above the float regulator  20  in an assembled state of the drip chamber  10  with the suction cup  23  closing the outlet  113  due to weight. Note that the outer diameter of the float regulator  20  is slightly smaller than an inner diameter of the drip chamber  10  so that the float regulator  20  may slidingly float in a portion of the drip chamber  10  under the filter  40 . 
         [0032]    An infusion tube  50  has one end connected to the outlet  113 . A catheter  60  has its female fitting connected to the other end of the infusion tube  50 . A manual flow control device  70  is mounted on the infusion tube  50  between both ends of the infusion tube  50 . 
         [0033]    An operation of the blood transfusion device will now be described. Blood L from the blood bag  90  begins to fill the drip chamber  10  via the pointed member  30  which pierces through the blood bag  90 . Blood L then flows through the filter  40  with impurities being removed by the mesh structure  44 . Next, blood L drops into the lower portion of the drip chamber  10  to accumulate therein and in both the upper cup  21  and the lower cup  22 . The buoyancy of blood L accumulated in the drip chamber  10  is increased gradually to be greater than the weight of the float regulator  20 . Therefore, the float regulator  20  begins to move upward to disengage from the outlet  113  to submerge in the drip chamber  10  (see  FIG. 5 ). 
         [0034]    Also, an amount of blood L leaves the drip chamber  10  and enters the infusion tube  50  to transmit to the catheter  60  which inserts into circulatory system of a patient. Thus, blood transfusion can be done. It is noted that the amount of blood transmitted to the patient can be regulated by the manual flow control device  70 . 
         [0035]    The upward movement of the float regulator  20  will be stopped when the projection  212  contacts the underside of the support  42  (see  FIG. 6 ). That is, the contact between the float regulator  20  and the filter  40  is a point contact rather than an area contact. Advantageously, it can prevent the float regulator  20  from being uneasily disengaged from the filter  40  once engaging because the viscosity of blood is higher than that of saline for intravenous (IV) infusion and it in turn can decrease the adherence of the float regulator  20  to the filter  40  (i.e., the point contact can decrease the adherence). 
         [0036]    To the contrary, the projection  212  may disengage from the filter  40  when the weight of the float regulator  20  is greater than the buoyancy of the blood L in the lower portion of the drip chamber  10  is decreased as the blood L continues to leave the drip chamber  10  with blood L in the blood bag  90  being used up. That is, the float regulator  20  begins to fall. Finally, the suction cup  23  closes the outlet  113  at the end of blood transfusion (see  FIG. 7 ). 
         [0037]    Advantageously, the closing of the outlet  113  is permanent as evidenced by inverting the drip chamber  10  (see  FIG. 8 ). Thus, blood in the infusion tube  50  is prevented from entering the drip chamber  10  via the outlet  113 . Also, a second blood supply to the drip chamber  10  via the blood bag  90  will not disengage the suction cup  23  from the outlet  113  even when blood accumulates in the drip chamber  10  as described in the previous paragraphs. Therefore, the blood transfusion device including the drip chamber  10 , the float regulator  20 , the pointed member  30 , the filter  40 , the infusion tube  50 , the catheter  60 , the manual flow control device  70 , and the needle  80  as well as the blood bag  90  can be discarded after use (i.e., disposable). 
         [0038]    Referring to  FIGS. 2 and 2A  in conjunction with  FIGS. 3 to 8 , the curved top  212 A also has the effect of decreasing contact area of the float regulator  20  and the filter  40  (i.e., being point contact). Therefore, after blood transfusion, the closing of the outlet  113  by the suction cup  23  is permanent. Blood in the infusion tube  50  is prevented from entering the drip chamber  10  via the outlet  113 . Also, a second blood supply to the drip chamber  10  via the blood bag  90  will not disengage the suction cup  23  from the outlet  113  even when blood accumulates in the drip chamber  10  as described with respect to the first preferred embodiment above. Therefore, the blood transfusion device including the drip chamber  10 , the float regulator  20 A, the pointed member  30 , the filter  40 , the infusion tube  50 , the catheter  60 , the manual flow control device  70 , and the needle  80  as well as the blood bag  90  can be discarded after use (i.e., disposable). 
         [0039]    While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.