Abstract:
The present invention is a blood separation system that is fully mechanized to collect blood from a patient, separate waste portions of the blood, wash the blood, and redirect the usable portions to a device for reinjecting the usable portions into the patient. The present invention prevents accidental activation of an improper operation that could cause harm to a patient or a shut down of the system by requiring confirmation of each step by an operator. The invention provides screen displays with detailed setup instructions, eliminating the need for secondary documentation that might not be allowed in a surgical environment. The invention also instructs the operator at the appropriate times to do certain manual steps such as opening and closing clamps. Since the opening and closing of clamps is a highly critical operation, confirmation of these steps is also required. A method and suitable apparatus is also disclosed for sequestration of platelet rich plasma whereby a blood sample is spun at a high speed sufficient to separate solid cells from the blood sample and spun at a lower speed for a predetermined time to allow platelets to elute from the solid cells.

Description:
This application is a division of Ser. No. 08/791,179, filed Jan. 31, 1997 now U.S. Pat. No. 5,964,734, and claims the benefit under 35 U.S.C. § 119(e) of the U.S. provisional patent application No. 60/010,939 filed Jan. 31, 1996. 
    
    
     TECHNICAL FIELD 
     The present invention relates to blood separation devices and methods in general and more particularly to blood separation devices and methods suitable for autotransfusion. 
     BACKGROUND ART 
     Surgical operations, including more complex operations where a substantial amount of bleeding may occur, may require transfusions during the course of the surgery to maintain a sufficient blood volume and blood pressure. Since many blood-borne diseases may exist including hepatitis, cancer and HIV, it is desirable to not require transfusion from another person. Also, if blood or blood components from the same person can be used, the necessity to match blood factors can be eliminated. 
     These disadvantages of receiving transfusions from donors are overcome by self-donation prior to operations. However, operations involving transfusions are not always identified in advance and few patients take the time and effort to go through the procedure. Additionally, a patient may be weakened by removal of blood prior to an operation. 
     Autotransfusion, whereby blood retrieved from the patient during the operation is separated so that reusable portions can be reinserted into the patient, is an effective method of overcoming the problems with transfusions. Various autotransfusion type systems currently exist but are somewhat complex to operate. For example, some autotransfusion systems require the operator to memorize a series of system steps to insure that the operator performs operations in the proper sequential order. Failure to perform the step or to perform the step in the proper sequence may cause the system to shut down or may cause morbidity in the patient. 
     Additionally, it is highly useful to have a blood separation system that can efficiently separate platelet and plasma from waste products in the blood. A high degree of efficiency in obtaining platelets has not been previously achieved. 
     It is therefore desirable to have a blood separation system that is highly efficient in extracting platelets from the blood, extracting waste products from the blood, allowing performance of operations in a simple and easy manner that does not require extensive knowledge of the system and processes, and preventing inadvertent or accidental operation of the blood separation device. 
     DISCLOSURE OF THE INVENTION 
     The present invention provides a blood separation system suitable for autotransfusion that displays instructions to guide the operator of the autotranfusion system to perform predetermined operation at predetermined times. In this manner, the operator of the system can be assured that the proper sequence of operations is being performed without a great degree of experience and knowledge of the system. 
     The present invention additionally requires confirmation of each operational step that is entered in the blood separation system by the operator to prevent the system from inadvertently being activated or performing an unintended operation that would necessitate the system being shut down or cause harm to the patient. 
     The present invention also is capable of separating blood platelets in a highly efficient manner from the blood sample by spinning the blood sample at a hard rate of approximately 5,600 rpm until the solid cells are separated from the blood sample, and then slowing the spin rate to a soft rate of about 2,400 rpm to allow the platelets to elute from the solid cells. The spin rate of 2,400 rpm is maintained for a period of approximately 60 seconds which allows the platelets to elute in a highly efficient manner. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Details of this invention are described in connection with the accompanying drawings that bear similar reference numerals in which: 
     FIG. 1 is a perspective view of a blood separation system embodying the present invention. 
     FIG. 2 is a diagram showing the sterile, disposable components of a blood separation system embodying the present invention. 
     FIG. 3 is control system diagram of a blood separation system embodying the present invention. 
     FIGS. 4A,  4 B,  4 C &amp;  4 D are representative views of screen displays of a blood separation system embodying the present invention. 
     FIG. 5 is a diagram showing the sterile, disposable components for platelet rich plasma sequestration for a blood separation system embodying the present invention. 
     FIGS. 6A,  6 B,  6 C,  6 D,  6 E,  6 F,  6 G, &amp;  6 H,  6 I,  6 J,  6 K,  6 L and  6 M are flow charts of a software program for a central processing unit for a blood separation system embodying the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1 there is shown a blood separation system embodying features of the present invention including a housing  1 , a peristaltic pump  2 , first, second, third clamps  3 ,  4 ,  5 , an air bubble sensor  6 , a centrifuge  7 , and a touch sensitive control screen  8 . The housing  1  is in general hexahedral or block shaped with vertical front wall, back wall, right side wall and left side wall, horizontal bottom wall, and top wall sloping downward from back to front. 
     The centrifuge  7  includes a centrifuge housing  9 , a centrifuge cover  10 , centrifuge drive means  11 , a centrifuge latch  12 , an upper centrifuge bowl clamp  13  and a drain port  13 . The centrifuge  7  is mounted within the right half of housing  1  and is vibrationally isolated from housing  1 . The top edge of centrifuge housing  9  slopes downwardly and forwardly so that the top edge is planar with the top surface of housing  1  when centrifuge  7  is installed in housing  1 . Centrifuge cover  10  is a shatter resistant transparent dome, convex up, pivotally attached to the back of centrifuge housing  9 , shaped so that the lower edge of centrifuge cover  10  covers the exterior of the top edge of centrifuge housing  9  forming a baffle and seals centrifuge  7  when centrifuge cover  10  is closed. Centrifuge latch  12  is attached to the front of centrifuge housing  9  and centrifuge cover  10 , and retains centrifuge cover  10  in a closed position whenever centrifuge  7  is operating. 
     Centrifuge drive means  11  is mounted in the bottom of centrifuge housing  9  and is variable speed, rotating between about 1000 rpm and 6000 rpm in 100 rpm increments. Upper centrifuge bowl clamp  13  is rigidly attached to the back wall of centrifuge housing  9 . Drain port  14  exits the centrifuge housing  9  at the lower right side, extending to the right side of housing  1 , providing drainage of washing/cleaning liquid during maintenance and drainage of blood component if the centrifuge bowl breaks. 
     Pump  2  is rigidly attached to left, forward portion of the top of housing  1  with the inlet and outlet of pump  2  generally directed away from the front, left corner of the top of housing  1 . Pump  2  is reversible and variable speed with capacity to pump between about 10 ml/min. and 1000 ml/min. 
     First, second, third clamps  3 ,  4 ,  5  are rigidly attached to the top of housing  1  adjacent to the inlet to pump  2 . Clamps  3 ,  4 ,  5  are color coded, first clamp  3  blue, second clamp  4  yellow and third clamp  5  red. Air bubble sensor  6  is rigidly attached to the top of housing  1  adjacent to the outlet to pump  2 . 
     Touch sensitive control screen  8  is mounted in housing  1  at the rear, left portion of the top of housing  1 , facing toward the front of housing  1 . 
     Referring to FIG. 2, a blood processing kit includes the disposable components of the blood separation system, including blood source tubing  21 , saline wash tubing  22 , processed blood tubing  23 , processed blood holding bag  24 , a first 4-way connector  25 , pump header tubing  26 , a centrifuge bowl  27 , centrifuge exit tubing  28  and waste bag  29 . Blood source tubing  21  is color coded blue, connecting to the source of the blood to be processed at a first end, passing through third clamp  5 , and connecting to the first 4-way connector  25  at the second end. Saline wash tubing  22  is color coded yellow, connecting to a saline source at a first end, passing through second clamp  4 , and connecting to the first 4-way connector  25  at the second end. Processed blood tubing  23  is color coded red, connecting to processed blood holding bag  24  at a first end, passing through first clamp  3 , and connecting to the first 4-way connector  25  at the second end. Pump tubing header connects to first 4-way connector at a first end, passes through pump  2 , air bubble sensor  6  and the left edge of centrifuge cover  10 , and connects to centrifuge bowl  27  at the second end. 
     Centrifuge bowl  27  is installed in centrifuge  7 , the base of centrifuge bowl  27  being held and rotated by centrifuge drive means  11  and the top of centrifuge bowl  27  being stabilized by upper centrifuge bowl clamp  13 . Centrifuge exit tubing  28  connects to centrifuge bowl  27  at a first end, passes through the right edge of centrifuge cover  10 , and connects at a second end to waste bag  29  which hang on the right side of housing  1 . 
     FIG. 3 shows the control system for a blood separation system embodying the present invention. The control system includes centrifuge control  39 , pump control  49 , clamp control  59 , operator interface  63  and system controller that is central processing unit  35 . 
     Centrifuge control  39  has a centrifuge motor  40  that rotates the centrifuge drive means  11 , a centrifuge motor controller  43  and centrifuge brake controller  42  that control the speed of rotation of centrifuge motor  40 , a centrifuge hall sensor  41  and a centrifuge encoder  44  that independently monitor the speed of rotation of centrifuge motor  40 , a centrifuge cover sensor  46  that senses whether centrifuge cover  10  is closed, and a centrifuge cover lock  45  that locks centrifuge latch  12  whenever centrifuge motor  40  is rotating above about 60 rpm. 
     Pump control  49  includes pump motor  50  that drives pump  2 , pump relay  51  that supplies power to pump motor  50 , pump motor controller  52  that controls the speed and direction of pump motor  50 , pump hall sensor  57  and pump encoder  56  that independently monitor the speed and direction of rotation of pump motor  50 , pump lid sensor  53  that senses whether the pump cover is closed, air bubble sensor  6  that senses whether fluid or air is flowing through pump header  26 , and level sensor  55  which signals when centrifuge bowl  27  is full of red cells. 
     Clamp control  59  includes clamp motor  60  which opens and closes first, second and third clamps  3 ,  4 ,  5 , clamp motor controller  61  which controls clamp motor  60 , and clamp position sensor  62  that determines the position of first, second and third clamps  3 ,  4 ,  5 . 
     The operator interface  63  includes a speaker  67  and the touch sensitive control screen d which has a display  64 , touch screen  65  and touch screen controller  66 . T ouch screen  65  is transparent, physically mounts over the display  64 , and provides operator input to the blood separation system. Display  64  is a 40 character by 6 line green fluorescent screen, and provides output and operator instructions. FIG. 4 shows examples of screen displays. Speaker  67  sounds an alarm signal when an alarm condition occurs in the blood separation system. 
     Central processing unit  35  coordinates the operation of the blood separation system, operating the pump  2 , clamps  3 ,  4 ,  5 , and centrifuge  7  in the proper sequence, direction and speeds, preventing pump  2  operation if the pump cover is open, preventing centrifuge  7  operation if the centrifuge cover  10  is open, locking centrifuge latch  12  when centrifuge  7  is rotating above about 60 rpm, monitoring fluid flow through air bubble sensor  6 , and displaying system status, pump volume and centrifuge speed during operation. Referring to FIGS. 4C and 4D, central processing unit  35  also provides a series of tutorial screens that guide the operator, step by step, through the setup of the disposable components of a blood processing kit, and screens showing the details of each alarm condition when such alarm condition occurs. Referring to FIG. 4A and 4B, after an operator selects an operation on touchscreen  65 , central processing unit  35  requires the operator to “accept” the selection by touching the ACCEPT position on touchscreen  65  before the blood separation system will proceed. 
     Central processing unit  35  has six preprogrammed software programs in ROM (Read Only Memory) including a Standard Program, Program A/trauma type applications, Program B/orthopedic applications, Program C/small volume applications, Program D/salvage type applications, and CONPLT/Concentrated Platelet Rich Plasma Sequestration. Programs A, B, C, D and CONPLT may be permanently reprogrammed by the operator, changes being stored in non-volatile RAM (Random Access Memory) maintained by battery back-up. The Standard Program and Programs A, B, C, D, CONPLT may be temporarily changed, the changes being lost when the blood separation system is turned off. 
     The Standard Program and Programs A, B, C, D may be run in “Automatic” mode. When “Automatic” mode is selected the blood separation system will proceed through the following steps without operator input. The first cycle is the fill cycle which starts with closing first clamp  3  and second clamp  4 , and opening third clamp  5 . The centrifuge drive means  11  begins to rotate, spinning centrifuge bowl  27 . When centrifuge  7  reaches about 5100 rpm pump  2  starts to pump unprocessed blood into centrifuge bowl  27 . As the centrifuge bowl  27  fills with blood, the heavier red cells are forced to the outside of centrifuge bowl  27  by centrifugal force while the lighter, undesirable components of the blood are forced inward, up and out of centrifuge bowl  27  through centrifuge exit tubing  28  to waste bag  29 . When level sensor  55  detects that centrifuge bowl  27  is full of red cells the fill cycle ends. 
     The wash cycle starts with third clamp  5  closing, second clamp  4  opening and pump  2  beginning to pump saline wash into centrifuge bowl  27 . After a predetermined period of time the wash cycle terminates, and pump  2  and centrifuge  7  stop. The empty cycle begins and pump  2  begins to pump fluid out of centrifuge bowl  27 . A small predetermined volume of fluid is backflushed into saline tubing  22 , then second clamp  4  closes and first clamp  3  opens so that the remaining washed red cells are pumped through the processed blood tubing  23  to holding bag  24  to await transfer to a transfer bag for reinjection into the patient. 
     The Standard Program and Programs A, B, C, D may also be run in “Semi-Automatic” mode. The blood separation system in “Semi-Automatic” mode follows the above sequence of steps but enters a standby mode at the end of the fill cycle and the end of the wash cycle, requiring operator selection of the next cycle before proceeding. 
     The blood separation system embodying features of the present invention will efficiently provide platelet rich plasma sequestration with the CONPLT Program. Referring to FIG. 5, the setup of the disposable components for platelet rich plasma sequestration is similar to the setup for red cell separation and washing but further includes a second 4-way connector  70 , platelet rich plasma tubing  71  connecting to second 4-way connector  70  at a first end, connecting to a platelet rich plasma (PRP) bag  72  at a second end and having a first manual clamp  77  in the middle which is closed during setup, platelet poor plasma tubing  73  connecting to second 4-way connector  70  at a first end, connecting to a platelet poor plasma (PPP) bag  74  at a second end and having a second manual clamp  78  in the middle which is closed during setup, and waste tubing  75  connecting to second 4-way connector  70  at a first end, connecting to waste bag  29  at a second end and having a third manual clamp  79  in the middle which is opened during setup. For platelet rich plasma sequestration the second end of centrifuge exit tubing  28  connects to 4-way connector  70  instead connecting to the waste bag  29  as in the standard setup. 
     Platelet rich plasma sequestration begins with a fill cycle identical to the fill cycle described above for the standard blood processing procedure. The fill cycle starts with closing first clamp  3  and second clamp  4 , and opening third clamp  5 . The centrifuge drive means  11  begins to rotate, spinning centrifuge bowl  27 . When centrifuge  7  reaches about 5100 rpm pump  2  starts to pump unprocessed blood into centrifuge bowl  27 . As the centrifuge bowl  27  fills with blood, the heavier red cells are forced to the outside of centrifuge bowl  27  by centrifugal force while the lighter, undesirable components of the blood are forced inward, up and out of centrifuge bowl  27  through centrifuge exit tubing  28  to waste bag  29 . If conservation of platelet poor plasma is desired, when the effluent reaches the first end of centrifuge exit tubing  28 , the operator places the blood separation system in “STANDBY” mode, opens second manual clamp  78 , closes third manual clamp  79  and releases “STANDBY” mode. When level sensor  55  detects that centrifuge bowl  27  is full of red cells the fill cycle ends. 
     At the end of the fill cycle the autotranfusion system automatically goes into “STANDBY” mode, slows the centrifuge  7  speed to about 2400 rpm, and displays the messages “Wait 60 seconds to loosen platelets” and “Unclamp PRP bag, then clamp PPP bag” on display  64 . The operator will manually open first manual clamp  77  and close second manual clamp  78 . After 60 seconds the platelet rich plasma separates from the red cells and moves to the inside top of centrifuge bowl  27 . The autotranfusion system displays the message “Have you unclamped the PRP bag and clamped the PPP bag?” on display  64 . When the operator confirms opening first manual clamp  77  and closing second manual clamp  78 , the autotranfusion system will again begin pumping blood into centrifuge bowl  27 , forcing the platelet rich plasma out of centrifuge bowl  27 , through centrifuge exit tubing  28 , second 4-way connector  70  and platelet rich plasma tubing  71 , to platelet rich plasma bag  72 . 
     When all of the platelet rich plasma has been pumped out of centrifuge bowl  27  and centrifuge exit tubing  28  begins to fill with red cells, the operator presses “EMPTY” then “ACCEPT” on touchscreen  65 . The blood separation system will display the message “Unclamp PPP bag and clamp PRP bag” and “Press STANDBY to continue” on display  64 . After the operator presses “STANDBY”, the blood separation system will display the message “Have you unclamped PPP bag and clamp PRP bag?” on display  64 . The operator opens second manual clamp  78 , closes first manual clamp  77  and presses “YES” on touchscreen  65 . The blood separation system pumps the red cells from the centrifuge bowl  27  and platelet poor plasma from platelet poor plasma bag  74  into holding bag  24 , completing the platelet rich plasma sequestration. 
     Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.