Blood processing system
A blood processing system ( 2 ), includes a housing ( 4 ), to which a user control panel is mounted, having an access opening ( 47 ) therein. A cassette assembly ( 22 ), mounted to the housing for movement between a use position covering the access opening and a cassette-replacement position, includes a cassette holder and cassette ( 26 ) removably mounted to the holder. The cassette includes in part by tubing aligned with a through-hole ( 45 ) in the cassette. A door ( 34 ) is mounted to the housing for movement between a latched position, capturing the cassette between the panel and the door, and a released position. Independently-driven roller assemblies ( 46, 54, 72 ) pass part-way through the access opening to capture first tubing portions ( 44 A, 52 A, 68 A) between the roller tracks ( 100, 102, 104 ) and the roller assemblies for peristaltic pumping of fluid. A number of movable pinch elements ( 48, 80, 90, 96 ) are extendable through the front panel to selectively pinch the tubing against the door and thus seal the tubing.
1. A blood washing system comprising:
an endless recirculation loop, fluidly coupled to an inlet for a source of blood;
a blood separator, having an entrance port, an exit port and a removed fraction port, defining a portion of the recirculation loop between the entrance and exit ports;
a pump situated along the recirculation loop operable to pump blood from and through the recirculation loop;
the blood separator configured to separate blood entering the entrance port into a retained fraction, which passes through the exit port, and a removed fraction, which passes through the removed fraction port, at least a portion of the retained fraction passing through the blood separator at least a second time;
a replacement fluid source fluidly coupled to the recirculation loop, whereby the replacement fluid source is configured to replace at least a part of the removed fraction; and
control means programmed to control the addition of replacement fluid so as to regulate hematocrit of the fluid in the recirculation loop, wherein the hematocrit is determined by measuring resistance to flow within the blood separator.
2. The system according to claim 1 wherein the control means acts to maintain said hematocrit within a desired range.
3. The system according to claim 1 wherein the removed fraction comprises at least one of plasma, free plasma hemoglobin, leukocytes, and viral inactivation compounds.
4. The system according to claim 1 wherein the retained fraction comprises red blood cells.
5. The system according to claim 1 wherein the retained fraction comprises plasma.
6. The system according to claim 1 wherein the replacement fluid is saline.
7. The system according to claim 1 wherein the replacement fluid includes glucose.
8. The system according to claim 1 wherein the pump stops when the amount of blood taken from the source has reached a predetermined amount and then the blood separator stops when the hematocrit has reached a predetermined hematocrit.
9. The system according to claim 1 wherein the source of blood is a chosen one of a donor vein, a patient's surgery site, a container of concentrated red blood cells and a container of thawed blood.
10. A method for washing blood comprising:
accessing a source of blood;
pumping blood from the source of blood through a recirculation loop, the recirculation loop comprising a blood separator;
separating the blood passing through the blood separator into a removed fraction and a retained fraction;
removing the removed fraction from the recirculation loop;
said pumping step being carried out so that at least a portion of the retained fraction passes through the blood separator at least a second time;
adding a replacement fluid to the recirculation loop;
determining a desired hematocrit of the blood in the recirculation loop by measuring resistance to flow within the blood separator; and
the adding step comprising controlling the amount of the replacement fluid added according to the desired hematocrit of the blood in the recirculation loop.
11. The method according to claim 10 wherein the removed fraction comprises at least one of plasma, free plasma hemoglobin, leukocytes, and viral inactivation compounds.
12. The method according to claim 10 wherein the retained fraction comprises red blood cells.
13. The system according to claim 10 wherein the retained fraction comprises plasma.
14. The method according to claim 10 wherein the replacement fluid is saline.
15. The method according to claim 10 wherein the replacement fluid includes glucose.
16. The method according to claim 10 wherein the blood pumping step is stopped when the amount of blood taken from the source has reached a predetermined amount and then the blood separating step is stopped when the desired hematocrit has reached a predetermined hematocrit.
17. The method according to claim 10 wherein the accessing step is carried out by fluidly coupling the recirculation loop with an inlet for a source of blood, the source of blood being a chosen one of a donor vein, a patient's surgery site, a container of concentrated red blood cells and a container of thawed blood.
18. The system according to claim 10 wherein the desired hematocrit is at least about 45%.
19. The system according to claim 10 where in the desired hematocrit is about 60–80%.