| 摘要 |
Blood is taken in batches from a donor via needle 12 and fed by pump 10 to a cross-flow membrane filter 16, from which separated plasma is delivered to bag 18 and concentrated cells are drawn by another pump 14 and fed to a reservoir 20 in the form of a flexible bag. When bag 20 is full its contents are returned to the donor, by a third pump 22, through the same needle 12. Anti-coagulant is added to the blood by fourth pump 26. During the filtering step, pump 10 is run at constant speed while the speed of pump 14 is varied in response to signals from pressure monitors 42, 58 to maintain constant transmembrane pressure. A further sensor 32, however, will stop pump 10 if the pressure falls unduly in line 30 during filtering and will control pump 22 to prevent excess pressure during concentrate return, thus protecting the donor. <IMAGE> |
