Abstract:
An intraoperative autotransfusion system and method of use. The system includes an autotransfusion device, a removable cassette, a cardiotomy reservoir, a container for holding washing fluid, and a reservoir for containing processed blood. The removable cassette includes a centrifugal cell, a peristaltic pump, and multiple clamps, each having fixed and sliding elements. The cassette has a housing and multiple ducts for connection to the cardiotomy reservoir.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to an intraoperative autotransfusion device.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is known that the technique of intraoperative autotransfusion is becoming increasingly widespread. This technique allows a patient to be reinfused with the patient&#39;s own blood, recovered in the operating field during the procedure. The blood is recovered by using devices that comprise a blood collection cardiotomy reservoir, a centrifugal cell in which the red cells are concentrated and washed with a suitable solution, and a reinfusion pouch in which the washed and concentrated red cells are made available for reinfusion to the patient.  
           [0003]    Known devices have less than fully satisfactory characteristics, and accordingly the aim of the present invention is to provide an intraoperative autotransfusion device which is easily managed by assigned operators and is highly reliable in operation.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention provides an intraoperative autotransfusion device having a centrifugal cell, a peristaltic pump and first, second, and third clamps, each clamp having a fixed element and a sliding element, as well as first, second and third channels defined between their respective fixed and sliding elements. Each clamp includes a sliding element and a fixed element defining a channel therebetween. The first channel is configured to accommodate a first duct having a first lumen connected between the centrifugal cell and a source of unprocessed blood. The second channel is configured to accommodate a second duct connected between the centrifugal cell and a reservoir for holding processed blood. The third channel is configured to accommodate a third duct connected between the centrifugal cell and a washing liquid container. Each of the sliding elements are configured to move from a first position which impinges upon the duct to substantially close the lumen, to a second position which does not impinge upon the duct so the lumen is substantially open.  
           [0005]    Also provided is a removable cassette that can be attached in an operational position on an intraoperative autotransfusion device having a centrifugal cell, a peristaltic pump and first, second, and third clamps, each clamp having a fixed element and a sliding element, as well as first, second and third channels defined between their respective fixed and sliding elements. The cassette includes a housing, first, second, and third ducts at least partially contained within the housing and each duct having a lumen. One end of the first duct is adapted for connection to a cardiotomy reservoir. One end of the second duct is adapted for connection to a container for holding washing liquid. One end of the third duct is adapted for connection to a reservoir for containing blood processed by the autotransfusion device. These ducts are secured within the housing at a location such that when the cassette is attached to the autotransfusion device in the operational position, the first, second and third ducts are positioned within the first, second and third channels, respectively. On the other ends of the ducts, a tube partially contained within the housing is fluidly connected. The tube&#39;s second end is adapted for connection to the centrifugal cell pf the autotransfusion device.  
           [0006]    In a further aspect of the invention, an intraoperative autotransfusion system is provided that comprises the autotransfusion device, the removable cassette, a cardiotomy reservoir for receiving blood from a patient, a container for holding washing fluid, and a reservoir for containing processed blood.  
           [0007]    In yet another aspect of the invention, a method of using the intraoperative autotransfusion system is provided. A method of processing and re-infusing a patient&#39;s blood comprising: providing an intraoperative autotransfusion device which includes a centrifugal cell, a peristaltic pump and first, second, and third clamps, each clamp having a fixed element and a sliding element, defining first, second and third channels therebetween through the first, second and third clamps, respectively; providing a cassette including a housing, first, second, and third ducts at least partially contained within the housing, and a tube at least partially contained within the housing and fluidly connected to second ends of the first, second, and thirds ducts, the tube having an end adapted for connection to the centrifugal cell, a first end of the first duct being connected to a cardiotomy reservoir suitable for receiving blood from the patient, a first end of the second duct being connected to a container suitable for holding washing fluid; installing the cassette into the autotransfusion device such that the first, second and third ducts are positioned within the first, second and third channels, respectively; a first end of the third duct being connected to a reservoir suitable for containing processed blood; fitting the tube around a raceway of the peristaltic pump; connecting the tube to the centrifugal cell; operating the pump in a first direction; moving the first sliding element from a first position to a second position to allow blood to flow through the first duct from the cardiotomy reservoir into the cell; filling the centrifugal cell with blood; operating the centrifugal cell to concentrate the cells of the blood; moving the first sliding element from the second position to the first position to stop blood flow in the first duct; moving the second sliding element of the second duct from a first position to a second position to allow washing liquid to flow into the centrifugal cell to wash the blood; discontinuing the operation of the centrifugal cell; moving the second sliding element from the second position to the first position to stop blood flow in the second duct; operating the pump in a second direction; and moving the third sliding element of the third duct from a first position to a second position to allow washed blood to flow to the processed blood container for reinfusion to the patient. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    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:  
         [0009]    [0009]FIG. 1 is a perspective view of a preferred embodiment of the invention;  
         [0010]    [0010]FIG. 2 is a blown up view of detail “A” of FIG. 1;  
         [0011]    [0011]FIG. 3 is a front view of a preferred embodiment of a cassette;  
         [0012]    [0012]FIG. 4 is a side view of a preferred embodiment of a cassette;  
         [0013]    [0013]FIG. 5 is a blown up view of a portion of the device;  
         [0014]    [0014]FIG. 6 is a sectional view, taken along line  6 - 6  of FIG. 5;  
         [0015]    [0015]FIG. 7 is a sectional view, taken along line  6 - 6  of FIG. 5, in a different step of operation than in FIG. 6;  
         [0016]    [0016]FIG. 8 is an exploded view of a motor assembly of the invention;  
         [0017]    [0017]FIGS. 9, 10 and  11  are views of three steps of the insertion of a supporting cassette in a preferred embodiment of the device. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    Referring now to the figures, cardiotomy reservoir  1  receives blood from the operating field, pouch  2  contains concentrated washed blood for reinfusion to the patient, and container  3  contains washing liquid. Reservoir  1 , pouch  2  and container  3  are connected by ducts  4 ,  5  and  6 , respectively, to cassette  7 .  
         [0019]    Within cassette  7 , ducts  4 ,  5  and  6  are connected, as shown in particular in FIG. 3, to a single tube  8 , of which a portion is preferably noose-shaped by virtue of the particular shape of the end  7   a  of a tab  7   b  of cassette  7 , as best seen in FIGS. 1 and 2. Tube  8  is inserted in peristaltic pump  9  and extends to centrifugal cell  10 , which is meant to be turned by conventional means not shown in the figure. A duct  11   a  for connection to a waste pouch  11  leads out from centrifugal cell  10 .  
         [0020]    Again referring to FIG. 3, end portions  4   a ,  5   a , and  6   a  of the ducts  4 ,  5  and  6 , respectively, before coupling to the tube  8 , are accommodated in the cassette  7  so that they are co-planar. When cassette  7  is inserted in an autotransfusion device (as shown in FIGS. 1 and 2), the portions  4   a ,  5   a  and  6   a  lie within three channels designated by the reference numerals  12 ,  13  and  14 , respectively, as shown in FIG. 5, with insertion criteria described hereinafter.  
         [0021]    The channel  12  is provided with a clamp which comprises movable sliding element  15 . Sliding element  15  is preferably kept in a closed position, as shown in FIGS. 5 and 6, where ridge  15   a  can be held against fixed element  16 , by the action of springs  17   a ,  17   b  as best seen in FIGS. 6 and 7.  
         [0022]    Likewise, channel  13  is provided with a clamp which comprises a movable sliding element  18  that is preferably kept in a closed position, as shown in FIGS. 5, 6 and  7 . In this closed position, ridge  18   a  preferably rests against fixed element  19 , by virtue of the action of springs  20   a  and  20   b.  Channel  14  is provided with a clamp comprising a movable sliding element  21  with a ridge  21   a  which is preferably kept in a closed position by the action of springs  22   a,    22   b  as seen in FIG. 8.  
         [0023]    Fixed safety pins, such as pin  23  for sliding element  15  and pin  24  for sliding element  18 , are provided to limit the movement of the sliding elements in both directions.  
         [0024]    Knob  25  is preferably operated manually by gripping handle  25   a . Knob  25  passes through cassette  7  within an opening  26  provided therein, and is connected by a grub screw  27  to a pivot  28 , which is monolithically coupled to a triple cam  29 . As seen in FIG. 8, cam  29  comprises elements  29   a,    29   b,    29   c,  which make contact preferably with sliding element portions  15   b,    18   b,    21   b,  respectively, for simultaneous actuation in a direction opposite the action of the previously mentioned springs.  
         [0025]    The knob  25  is provided with a lock for securing cassette  7  when it is inserted in the device. The lock may comprise a gradually sloping tooth  30 . Tooth  30  is preferably shaped complementarily with respect to notch  26   a  provided at the rim of opening  26  of the cassette  7 . A second tooth formed by portions  31   a  and  31   b,  which is shaped complementarily with respect to the notch which is formed by the two portions  26   b,    26   c  is provided at the rim of the opening  26 . At the rim of opening  26  there is also a notch  26   d,  which allows easy passage of handle  25   a  with a wide clearance.  
         [0026]    As seen in FIGS. 6 and 7, a motorized cam  32  can be monolithically connected to the pivot  33 . Pivot  33  is associated with an output shaft  34   a  of an electric motor  34  and can be locked thereon by virtue of a grub screw  35 .  
         [0027]    Cam  32  is preferably inserted in the device coaxially to pivot  28  of triple cam  29  that rests thereon so that it is centered and can rotate freely. Cam  32  is suitable to make contact with one sliding element at a time, according to an operating logic of the device described hereinafter, at the portions  15   c,    18   c,    21   c  of the sliders to cause them to move in contrast with the action of the springs.  
         [0028]    A rod  36 , which is coaxial to the pivots  28  and  33 , passes inside them and is rigidly coupled, at its lower end, to pivot  33  for the manual actuation of motorized cam  32  if electric motor  34  fails to operate.  
         [0029]    Referring again to FIG. 2, a hematocrit sensor  37  comprised within block  37   a  can be provided for accommodating terminal  7   a  and the corresponding tab  7   b  of the cassette  7 . Referring to FIG. 6, optical sensors  38  working in combination with phonic wheel  39  on pivot  33  can detect the position of the motorized cam. Optionally, additional sensors can be provided within the device if desired.  
         [0030]    The operation of the invention generally begins with the insertion of cassette  7  in the device (shown in FIGS. 5 and 6) with knob  25  at its first stroke limit and cam  32  in a neutral position, so as to not actuate any sliding elements. Cassette  7  is positioned so that the opening  26  lies at knob  25 , accommodating terminal  7   a  with tab  7   b  in the block  37   a.  Tube  8  is then connected to centrifugal cell  10  and inserted in the peristaltic pump  9 . Cassette  7  preferably is prohibited from moving downward by having the sliding elements  15 ,  18 ,  21  in their closed positions, so as to prevent the passage of the ducts, and also by having teeth  30  and  31   a,    31   b  interfere with the plane of the cassette. This condition is shown in FIG. 9.  
         [0031]    Knob  25  is then turned to bring it to its second stroke limit as shown in FIG. 10, keeping it motionless in the position that it has reached in order to overcome the action of the springs that act on the sliding elements  15 ,  18  and  21  in contact with the triple cam  29  connected thereto. This results in the dual effect of simultaneously moving the sliding elements, by virtue of the action of the triple cam, into the open position, and of arranging the teeth  30  and  31   a,    31   b,  at the notches  26   a  and  26   b,    26   c,  respectively, provided at the rim of the opening  26  of the cassette.  
         [0032]    Cassette  7  can then be moved downward to a working position by inserting the duct portions  4   a ,  5   a  and  6   a  respectively in channels  12 ,  13 ,  14 . Correctness of the operation can be ensured by the presence of the reference tooth  31   b  inserted in the corresponding notch  26   c.    
         [0033]    When knob  25  is released, and by virtue of the thrust applied by sliding elements  15 ,  18  and  21  due to the action of the corresponding springs against triple cam  29 , the knob returns to the initial position, as shown in FIG. 11, with the cassette  7  locked by teeth  30  and  31   a,    31   b  and with the duct portions  4   a ,  5   a ,  6   a  closed by the respective clamps. This is the position shown in FIGS. 1, 2,  5 ,  6 ,  8  and  11 .  
         [0034]    After starting the rotation of centrifugal cell  10  and starting peristaltic pump  9 , the controller of the device activates electric motor  34  which moves cam  32  from the neutral position, shown in FIGS. 6 and 8, to the position shown in FIG. 7, with a movement of sliding element  15  which produces the opening of the portion  4   a , as shown in the FIG. 7, of the duct  4  that arrives from the cardiotomy reservoir  1 . Blood can thus flow from cardiotomy reservoir  1  into centrifugal cell  10 , and the step for filling the cell and concentrating the red cells can be performed. Upon completion of filling and concentrating, the motor is caused to turn cam  32  to close sliding element  15  and actuate sliding element  21  to open portion  6   a  of duct  6  that arrives from the washing liquid container  3 . This opens duct  6  to allow washing liquid to flow into centrifugal cell  10 . The centrifugal cell  10  and peristaltic pump  9  continue to turn and the step for washing the concentrated red cells is completed. The waste is sent to pouch  11 .  
         [0035]    Once washing has been completed, cell  10  stops, cam  32  is caused to rotate to actuate sliding element  18 . This results in the closure of duct portion  6   a  and the opening of portion  5   a  of duct  5  which is connected to the pouch  2 . The peristaltic pump  9  then reverses the direction of its rotation and sends the concentrated and cleaned blood to the pouch  2  for reinfusion to the patient. The process is thus complete, and cassette  7  can then be released by actuating the knob  25 .  
         [0036]    The described invention is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may furthermore be replaced with other technically equivalent elements.