Abstract:
A vacuum assisted venous blood reservoir has a controller that can sense pressure within a sealed blood chamber. The controller regulates the amount of vacuum within the chamber to control the level of blood in the venous reservoir. A safety valve is included to prevent blood from entering the vacuum line.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a venous blood reservoir in extracorporeal circuit.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is known that many surgical procedures entail the need to divert the blood of the patient into an extracorporeal circuit that comprises blood accumulation reservoirs. One of the reservoirs is the so-called venous reservoir, which receives the blood, known as venous blood, from the patient before it is passed through an oxygenation apparatus, which is also included in the extracorporeal circuit. Another of the reservoirs is designed to contain blood collected in the operating field, which once appropriately filtered can be returned to the patient; this reservoir is known as a cardiotomy reservoir.  
           [0003]    The venous reservoirs of the prior art receive the blood that arrives from the patient by gravity, and this entails a forced placement of such reservoirs at a lower level than the operating field, which is often poorly compatible with the limited space available. It should also be noted that the blood circulation provided by gravity is not always as efficient as would be desirable. One way to increase the efficiency of drainage is to apply a vacuum to the interior of the reservoir. However, such vacuum assisted reservoirs have not, in the past, been combined with a cardiotomy reservoir to form a reservoir system having features desired by the user.  
         SUMMARY OF THE INVENTION  
         [0004]    The aim of the present invention is therefore to provide a venous reservoir that ensures intensive drainage of the blood of the patient without any limitation in selecting its location. Within this aim, an object of the invention is to devise a venous reservoir combined with a cardiotomy reservoir.  
           [0005]    The proposed aim is achieved by a venous blood reservoir according to the invention, comprising an inlet connector that is connected to a line for drawing blood from the patient, and an outlet connector for the outflow of the blood toward an oxygenation apparatus, characterized in that it comprises, at the upper lid, a connector that is adapted to be connected to a line that reaches a vacuum source. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    Further characteristics and advantages will become better apparent from the description of a preferred but not exclusive embodiment of the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein:  
         [0007]    [0007]FIG. 1 is a general sectional view of the device of this invention, taken along the line I-I of FIG. 2;  
         [0008]    [0008]FIG. 2 is a sectional view, taken along the line II-II of FIG. 1;  
         [0009]    [0009]FIG. 3 is an enlarged-scale view of the upper region of FIG. 2 in a different functional condition; and  
         [0010]    [0010]FIG. 4 is a detail view of the device of this invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]    With reference to the figures, reference number  1  designates the enclosure of the combined device. Enclosure  1  includes a first chamber or portion comprising a venous reservoir  2  and a second chamber or portion comprising a cardiotomy reservoir  4 . Venous reservoir  2  is positioned below cardiotomy reservoir  4  and the two reservoirs are separated by a generally horizontal partition  3 . It should be understood, however, that the concepts of the present invention disclosed herein are not limited to a venous reservoir combined with a cardiotomy reservoir but are equally applicable to stand-alone venous reservoirs.  
         [0012]    The venous reservoir  2  is provided with an inlet connector  5  for the inflow of the venous blood, into a central region  5   a  that is defined by a wall  6 . Wall  6  comprises a bubble rupturing substance and is surrounded by a filter  6   a . Venous reservoir  2  is also provided with an outlet connector  7  for the outflow of the blood. Thus, blood entering venous reservoir  2  through inlet connector  5  is directed to central region  5   a . Before the blood exits the venous reservoir, it passes through wall  6  and filter  6 a where bubbles and other undesirable materials are removed.  
         [0013]    The cardiotomy reservoir  4  is provided with an inlet connector  8  for the inflow of the blood that arrives from the operating field. Inlet connector  8  opens into a region  8 a that is defined by wall  9 , which comprises a bubble rupturing substance. Wall  9  is surrounded by a filter  9   a.    
         [0014]    The partition  3  has a central opening  10 , which connects the cardiotomy reservoir  4  to the venous reservoir  2 . Means are provided for closing central opening  10 . Manual action on tab  11  a will cause column  11  to slide between a lower stroke limit position (as shown in FIGS. 1 and 2), thus closing opening  10 , and an upper stroke limit position ( as shown in FIG. 3), in which opening  10  is open in order to allow emptying of the blood contained in the cardiotomy reservoir into the underlying venous reservoir.  
         [0015]    If it is necessary to empty the cardiotomy reservoir while opening  10  is closed, the duct  11   b  provided in the column  11  is used. Duct  11   b  is open at the lower end into the cardiotomy reservoir to allow aspiration through the open upper end.  
         [0016]    An important feature of the invention is that partition  3 , comprising the upper lid of the venous reservoir  2 , is provided with a connector  12 , which comprises a duct which communicates with a lower end of duct  13  formed within the upper structure of the enclosure  1 . As best seen in FIG. 4, an upper end of duct  13  joins coupling  14  which has a vacuum port comprising a connector  15  that is adapted to be connected to a line that is attached to a vacuum source.  
         [0017]    The connection of the coupling  14  to the upper end of the duct  13  is provided by means of the threaded ring  16 , which allows rotation of the coupling. A safety valve  17  contained within coupling  14  prevents vacuum from exceeding a desired level.  
         [0018]    During use of the device, vacuum is applied to venous reservoir  2  by connecting connector  15  to a vacuum source. The formation of vacuum in the venous reservoir  2  results in an effective drainage of the blood that arrives from the patient, and this occurs regardless of the level at which the venous reservoir is arranged with respect to the operating field.  
         [0019]    As best seen in FIG. 1, within the connector  12  there is a float  18 , which in the inactive or open position (shown in FIG. 1) rests on a frame  19 . Float  18  is provided with needle  18   a , which is adapted to close an opening  20  that connects the connector  12  to the duct  13  when float  18  is moved to the active or open position. If the blood contained in the venous reservoir  2  reaches a level where it enters connector  12  creating a situation that might lead to invasion of the vacuum line on the part of the blood, float  18  will be caused by the blood to move upwardly in turn moving needle  18   a  to a position which blocks opening  20  to duct  13 , thus preventing blood from entering the vacuum line.  
         [0020]    The return of the float  18  to the inactive position, once the emergency has ended, is facilitated by the temporary connection of the space within duct  13  that lies above the float to atmospheric pressure. This is accomplished by opening a small hole  21  provided in the coupling  14  by deformation of an elastic ring  22 , which normally keeps the hole closed, the deformation being caused by the operator by manually acting on a tab  22   a.    
         [0021]    A turret  23  opens into venous reservoir  2  and extends from partition  3 . It is joined by means of duct  23   a  to connectors  24   a  and  24   b  for connection to lines that are normally closed in order to maintain a desired amount of vacuum in the reservoir  2 . The turret is adapted for the introduction, when necessary, of medical liquids into the reservoir.  
         [0022]    The venous reservoir according to the invention is provided with a control system comprising a device capable of automatic adjustment of the level of the blood contained therein based upon pressure within the reservoir. The control system includes a computer schematically designated by the reference numeral  25 . The pressure at the base of the reservoir and the negative pressure at the top of the reservoir are continuously sensed and provided to the computer. The pressure at the top and bottom of the reservoir is sensed through ducts  25   a  and  25   b , respectively. The computer adjusts the amount or degree of vacuum that is present in the reservoir based on the sensed pressure data to maintain the proportion between the flow-rate of the incoming blood and the flow-rate of the outgoing blood, to keep the level of the blood in the venous reservoir substantially constant.  
         [0023]    The described invention is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; thus, for example, the device for automatic adjustment of the level of the blood in the reservoir can be provided in any manner and the cardiotomy reservoir can be omitted.  
         [0024]    Furthermore, connector  15  adapted to be connected to the vacuum line can branch out from the wall of the enclosure  1  proximate to the partition  3 .