one embodiment of the device of the present invention is depicted in fig1 - 4 . regarding fig2 and 3 , and for the sake of clarity , a view of the device taken along plane ii — ii of fig1 is shown . in fig2 and 3 , the column 16 has been rotated 90 ° into the page with respect to its position shown in fig1 . with reference to the above figures , the reference numeral 1 designates a housing of the device and the reference numeral 2 designates a partition which divides the space enclosed by the housing 1 into a venous reservoir 3 , and a cardiotomy reservoir 4 . the housing is preferably formed of a transparent polymer to allow the interior of the device to be viewed by an operator . numerous transparent , medically useful polymers are known to those having ordinary skill in the art . the venous reservoir 3 is provided with an venous inlet connector 5 , terminating at 5 a , for the venous blood . venous blood entering the venous reservoir 3 through the venous inlet connector 5 enters a distribution chamber 22 where it is passed outward , in a substantially uniform manner , into a central region of the venous reservoir through a plurality of slotted apertures 23 formed in the distribution chamber 22 . the central region of the venous reservoir is defined by a generally cylindrical wall 6 of a defoaming material . the defoaming material is surrounded by a filter 6 a through which the blood must also pass as it enters the venous reservoir 3 . blood exits the venous reservoir 3 through a venous outlet connector 7 . in one embodiment , the defoaming material comprises a porous polymeric material such as a polyurethane foam . in one preferred embodiment , the defoaming material is a polyurethane foam having a pore size of approximately 5 to 50 pores per inch , more preferably approximately 20 to 30 pores per inch . the defoaming material may optionally be treated with a medically acceptable antifoaming agent such as a silicone antifoaming agent . the filter is a screen , preferably formed of a polyester , having an aperture size in the range of about 20 to 50 microns . the top of the venous reservoir 3 is defined by a partition 2 which separates the venous reservoir 3 from the cardiotomy reservoir 4 . the cardiotomy reservoir 4 is provided with a cardiotomy inlet connector 8 for receiving blood arriving from the operating field , and an air outlet connector 10 . blood entering the cardiotomy reservoir 4 through the cardiotomy inlet 8 first encounters a flow distributor 24 , which distributes the blood outwardly in a substantially uniform manner . as with the blood entering the venous reservoir , the blood next encounters a generally cylindrical wall 9 of a defoaming material . the defoaming material is surrounded by a filter 9 a through which the blood must also pass as it enters the cardiotomy reservoir 4 . the defoaming material is as described above , namely , a porous polymeric material such as a polyurethane foam . as before , in one preferred embodiment , the defoaming material is a polyurethane foam having a pore size of approximately 5 to 50 pores per inch , more preferably approximately 20 to 30 pores per inch , and the filter is a screen , preferably formed of a polyester , having an aperture size in the range of about 20 to 50 microns . the partition 2 which separates the venous and cardiotomy reservoirs is typically a substantially flat plate . when the device is in operation , it is positioned in a manner that maintains the partition in a substantially horizontal orientation . the partition 2 is provided with a plurality of apertures that provide for operation of the device in the manner discussed below . in one embodiment , shown in fig1 - 3 , the partition 2 includes two apertures 11 and 12 , from which extend two ducts 13 and 14 . the ducts preferably extend substantially at right angles to partition 2 and therefore are maintained in a vertical orientation when the device is oriented in its proper operating position . the ducts 13 and 14 extend into the cardiotomy reservoir 4 and reach approximately the same elevation . the upper edge of each duct is typically provided with a plurality of axial notches 15 . an axially moveable column 16 is positioned preferably in the center of the cardiotomy reservoir 4 and extends upward through the housing 1 . the column 16 includes a first passageway 17 and a second passageway 18 . in the first passageway 17 , a lower end 17 a communicates with the venous reservoir 3 through a central aperture 20 in the partition 2 , and an upper end 17 b communicates with the cardiotomy reservoir 4 . likewise , in the second passageway 18 , a lower end 18 a communicates with the cardiotomy reservoir 4 and an upper end 18 b communicates with the exterior of the housing . column 16 can be caused to move axially by manual action on tab 19 . as such , the column can be moved between a lower stroke limit position , illustrated in fig1 and 2 , and an upper stroke limit position , shown in fig3 . while in the lower stroke position , the lower end 17 a of the first passageway is sealingly inserted into a central aperture 20 provided preferably at the center of the partition 2 . the seal may optionally be enhanced through the use of an o - ring 25 positioned around the exterior of the lower end 17 a of the first passageway . the seal , when engaged , serves to prevent blood in the cardiotomy reservoir from entering the venous reservoir . when the seal is engaged , the upper end 17 b of the first passageway is caused to be positioned at an elevation which is above that of the upper edges of the ducts 13 and 14 . alternatively , when the column 16 is moved into its upper stroke position , the lower end 17 a of the first passageway 17 is extracted from the central aperture 20 , thereby disengaging the seal and allowing blood in the cardiotomy reservoir 4 to flow directly into the venous reservoir 3 . it should be noted that regardless of the position of the column 16 , fluid communication through the second passageway 18 is substantially unaffected . a second o - ring 27 may optionally be provided around the exterior of an upper portion of the column 16 . the second o - ring 27 serves to provide a seal between the upper portion of the column and the portion of the housing 1 through which the column passes . when the column 16 is at the lower stroke limit , i . e ., in the position shown in fig1 and 2 , blood flowing into venous inlet connector 5 enters the venous reservoir 3 . if the amount of blood entering the venous reservoir is greater than the amount exiting through the venous outlet connector 7 , the level of blood inside the venous reservoir 3 is caused to rise . it is possible that the rising level of blood can lead to the complete filling of the venous reservoir . at this point , one advantage of the present invention becomes apparent , since an additional accumulation of blood is allowed because the blood can enter the ducts 13 and 14 , as well as the first passageway 17 . such excess blood can then rise in the ducts and passageway until it overflows into the cardiotomy reservoir 4 through the ducts 13 and 14 . by integrating the venous reservoir 3 and the cardiotomy reservoir 4 , the device , whenever necessary , allows the accumulation of an amount of venous blood which is far greater than the capacity of the venous reservoir alone . integration of the venous and cardiotomy reservoirs also allows air and other gaseous emboli entrained in the venous blood , resulting for example from poor cannulation , to be released from the device by passing through the ducts 13 , 14 and the first passageway 17 and allowing it to collect in the upper portion of the cardiotomy reservoir 4 , from which it may exit or be withdrawn through the air outlet connector 10 . likewise , the functionality of the cardiotomy reservoir 4 is also enhanced . specifically , blood entering the cardiotomy reservoir 4 through the cardiotomy inlet connector 8 gradually rises in that reservoir until it is almost filled . rather than completely filling the cardiotomy reservoir , however , once the blood reaches a certain level , it is caused to enter the ducts 13 and 14 and flow downward therethrough , accumulating in the venous reservoir 3 . as such , the device is configured to allow excess accumulation of either venous or cardiotomy blood . even if excess cardiotomy blood is flowing into the venous reservoir , air and other gaseous emboli present in the venous blood can still be removed from the device . since the upper end 17 b of the passageway 17 is configured to remain above the upper edges of the ducts 13 and 14 , even if the ducts are communicating blood into the venous reservoir , the passageway 17 remains blood - free and capable of communicating air from the venous reservoir into the cardiotomy reservoir , and ultimately , to the exterior of the housing through the air outlet connector 10 . when the column 16 is positioned at its upper stroke limit , as shown in fig3 all of the blood contained in the cardiotomy reservoir 4 will flow into the underlying venous reservoir 3 through the central aperture 20 . as such , in this configuration , the central aperture 20 acts as a drainage port which may be plugged and unplugged by the column 16 . finally , it should be noted that a situation can arise in which the operator does not wish to mix blood contained in the cardiotomy reservoir 4 with blood contained in the venous reservoir 3 . this can occur , for example , if undesirable substances are present in the cardiotomy blood . in that situation , the blood contained in the cardiotomy reservoir is effectively isolated from the blood in the venous reservoir and can be completely removed from the device through passageway 18 . it should be noted that the advantages of the device of the present invention are not intended to be strictly limited to those described above . for example , in the embodiments of the device shown in fig1 - 4 , the amount of blood contact with the internal surfaces of the device has been minimized , as has the possibility of reverse filtration of blood contained within the device . furthermore , due to the relatively non - complex design and operation of the device , the device will respond rapidly to control manipulations by the operator . of course , the described invention is amenable to numerous modifications and variations , all of which are intended to be within the scope of the inventive concept . thus , for example , the number of ducts provided on the partition can be different from the configuration described . likewise , the invention is not intended to be limited to the particular materials employed , nor to the shapes or any dimensions employed . rather , the device may be made according to the specific requirements of a particular application for which its use is intended . various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention . it should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows .
a combined device having a reservoir for venous blood and a reservoir for cardiotomy blood is disclosed . the device is characterized in that the venous reservoir is separated from the cardiotomy reservoir by a partition which includes a plurality of apertures . the apertures are in fluid communication with a plurality of ducts and passageways which are configured to provide various modes of operation depending upon whether , for the particular surgical conditions , it is desired to mix venous and cardiotomy blood , or to isolate those blood pools from each other .