Blood bank
A blood bank is a center where blood gathered as a result of blood donation is stored and preserved for later use in blood transfusion. The term "blood bank" typically refers to a division of a hospital where the storage of blood product occurs and where proper testing is performed (to reduce the risk of transfusion related adverse events). However, it sometimes refers to a collection center, and indeed some hospitals also perform collection.
Storage and management[edit]
Routine blood storage is 42 days or 6 weeks for stored packed red blood cells (also called "StRBC" or "pRBC"), by far the most commonly transfused blood product, and involves refrigeration but usually not freezing. There has been increasing controversy about whether a given product unit's age is a factor in transfusion efficacy, specifically on whether "older" blood directly or indirectly increases risks of complications.[15][16] Studies have not been consistent on answering this question,[17] with some showing that older blood is indeed less effective but with others showing no such difference; nevertheless, as storage time remains the only available way to estimate quality status or loss, a first-in-first-out inventory management approach is standard presently.[18] It is also important to consider that there is large variability in storage results for different donors, which combined with limited available quality testing, poses challenges to clinicians and regulators seeking reliable indicators of quality for blood products and storage systems.[19]
Transfusions of platelets are comparatively far less numerous, but they present unique storage/management issues. Platelets may only be stored for 7 days,[20] due largely to their greater potential for contamination, which is in turn due largely to a higher storage temperature.
RBC storage lesion[edit]
Insufficient transfusion efficacy can result from red blood cell (RBC) blood product units damaged by so-called storage lesion—a set of biochemical and biomechanical changes which occur during storage. With red cells, this can decrease viability and ability for tissue oxygenation.[21] Although some of the biochemical changes are reversible after the blood is transfused,[22] the biomechanical changes are less so,[23] and rejuvenation products are not yet able to adequately reverse this phenomenon.[24]
Current regulatory measures are in place to minimize RBC storage lesion—including a maximum shelf life (currently 42 days), a maximum auto-hemolysis threshold (currently 1% in the US), and a minimum level of post-transfusion RBC survival in vivo (currently 75% after 24 hours).[25] However, all of these criteria are applied in a universal manner that does not account for differences among units of product;[19] for example, testing for the post-transfusion RBC survival in vivo is done on a sample of healthy volunteers, and then compliance is presumed for all RBC units based on universal (GMP) processing standards. RBC survival does not guarantee efficacy, but it is a necessary prerequisite for cell function, and hence serves as a regulatory proxy. Opinions vary as to the best way to determine transfusion efficacy in a patient in vivo.[26] In general, there are not yet any in vitro tests to assess quality deterioration or preservation for specific units of RBC blood product prior to their transfusion, though there is exploration of potentially relevant tests based on RBC membrane properties such as erythrocyte deformability[27] and erythrocyte fragility (mechanical).[28]
Platelet storage lesion[edit]
Platelet storage lesion is a very different phenomenon from RBC storage lesion, due largely to the different functions of the products and purposes of the respective transfusions, along with different processing issues and inventory management considerations.[31]
Alternative inventory and release practices[edit]
Although as noted the primary inventory-management approach is first in, first out (FIFO) to minimize product expiration, there are some deviations from this policy—both in current practice as well as under research. For example, exchange transfusion of RBC in neonates calls for use of blood product that is five days old or less, to "ensure" optimal cell function.[32] Also, some hospital blood banks will attempt to accommodate physicians' requests to provide low-aged RBC product for certain kinds of patients (e.g. cardiac surgery).[33]
Blood Banking and Donation
Blood banking refers to the process of collecting, separating, and storing blood. The first U.S. blood bank was established in 1936. Today, blood banks collect blood and separate it into its various components so they can be used most effectively according to the needs of the patient. Red blood cells carry oxygen, platelets help the blood clot, and plasma has specific proteins that allow proper regulation of coagulation and healing. Although research has yielded drugs that help people's bone marrow produce new blood cells more rapidly, the body's response time can still take weeks, thus donated blood remains an important and more immediate life-saving resource.
Blood is the vital connection to having a healthy body, and according to the American Red Cross, nearly 5 million people receive blood transfusions each year. Thanks to years of research, much progress has been made towards making transfusions safer and more effective.
No comments:
Post a Comment