Update on Blood Transfusion
Blood transfusion procedures have changed a lot during the past 10 years, not to mention the great developments in how blood was taken from donors, and given to patients, which already have taken great steps forward.
When was the first blood transfusion procedure?
Blood transfusion didn't start until 1492, when a Roman physician recommended blood transfusion as a treatment method for Pope Innocent VIII. Until then, no one could ever have imagined how fast and advanced blood transfusion could have reached as regards its potential for therapy, diversity and opportunity for further research. Blood transfusion practice has branched so much in treating diseases that it has passed the level of fame as a therapeutic option to the new level of increased awareness of its risks, and raising more knowledge to its potential harms and risks, in an attempt to drive health care providers to know about new policies that will highlight the importance of appropriate use of blood to stay away from its risks.
Have you ever heard before of "blood components" or "products"?
The term " blood " has now been replaced by " blood products ", which - for the sake of today's introduction - roughly means packed red cells, plasma and its derivatives, platelets, and some coagulation factors. For a long time it has been thought that blood was the magical treatment of a lot of diseases and conditions, simply because it contained the above ingredients. But as time went on, it became obvious that blood was a scarce asset because not so many donors wanted to give their blood for a lot of reasons. Blood banks thought of storing blood. With more experiments and research, it was discovered lately that the main (products) of (whole) blood could be separated from it by the power of centrifugation, that is, allowing whole blood bags to be spun in rotating cups of machines at certain speeds, which also made the different components of blood separate from each other according to their specific gravity. So, red blood cells, having the highest specific gravity, would settle at the bottom of the bag, while platelets, with the least specific gravity would stay on top, whereas plasma, having medium gravity, lies between red cells below and platelets above. This separation was done before the time of centrifuges by hanging blood bags overnight inside fridges in blood banks, but it took almost 24 hours to be done, besides the fact that it was not good practice for production of effective blood products, as we will know in later articles.
What are the ideal storage conditions for different blood products?
It has been discovered that in order to keep blood products with maximum therapeutic abilities, they have got to be stored at specific temperatures. According to the American Association of Blood Banks (AABB), it is recommended that red blood cells be kept in fridges with temperatures ranging between 2-6 oC. Plasma should be stored at below 0oC, whereas platelets should be kept at room temperatures between 20-22 oC. A lot of policies have been introduced by the AABB and the European Council of Blood Banks in order to make blood transfusion a much more risk-free practice with the least possible adverse reactions or transmitted infections to the recipients.
Is that all? No, not yet. We're just getting warmed up..
Not only were blood banks not willing to transmit infections with the received blood, they also introduced "special processing" of blood units through techniques like washing, filtration and irradiation of blood units. These techniques were introduced to free blood components from harmful proteins that are linked to white blood cells. These proteins - if not - removed, would lead to various body reactions that range from simple rash that may occur after transfusion, to the most dangerous of all transfusion reactions, which occurs as a result of a total whole body immune response, that leads to massive widening of the caliber of blood vessels throughout the body, which may - if not treated fast - lead to the inevitable.
How old is your blood bag? The doctor wants a fresh one.
One of the other major breakthroughs in blood transfusion was the determination of expiry dates for different blood products. After the expiry date, blood products become useless if not harmful and should never be given to patients. Whole blood and red bood cells has an average expiry date of 35 days when blood is collected in an anticoagulant preservative called CPDA-1 (Citrate-Phosphate-Dextrose-Adenosine), although that expiry date may be more or less with different other preservatives. Plasma can be kept in freezers for as long as 3 months if kept at -18 to -23 oC, and as much as 6 months if kept at -23 oC and above. Platelets become expired after only 5-7 days of storage.
Donate blood. Save a life!!
There have also been improvements in methods of blood donation, blood testing for infectious agents, as well as blood ordering policies and issuing of different blood components. For example, nowadays, most modern blood banks or those affiliated with higher US or European policies use selection criteria for blood donors, a requirement that was not there 10 years ago. These selection criteria raised the quality of blood donated at the expense of creating a much less donor pool for future healthcare needs. Blood banks now are trying to compensate for that by adopting "donor retention" policies, where voluntary non-remunerated blood donor pools are being created with the hope of convincing them to repeat their blood donations with the same blood bank again and again for the whole length of their healthy lifetime. More will be highlighted in future articles.
Are we efficiently using the blood products that we have?
No, I wouldn't say so. The most imminent challenges for blood transfusion services nowadays are matters of increasing blood donor pools for future crises, quality control over blood products, and raising the awareness of all members of the clinical team as regards what is known as the "appropriate use of blood". Except for very rare cases, it is considered obsolete nowadays to order whole blood for patients diagnosed with anemia. By providing these patients with only packed red blood cells (only one component of whole blood), their anemia will be gradually cured without loading up their circulation with more fluids (plasma and platelets) which actually they don't need. Within the following articles, we will be discussing the major features of blood and blood derivatives as therapeutic agents, together with highlighting some interesting therapeutic procedures done within modern blood transfusion services to provide therapy for different patients.
- Klein HG, Anstee DJ. Mollison's Blood Transfusion in Clinical Medicine, 11th edition. Oxford: Blackwell Publishing Ltd; 2005.
- Brecher ME, ed. Technical Manual, 15th Ed. Bethesda, MD: AABB Press; 2005.
- Popovsky MA, ed. Transfusion reactions, 3rd Ed. Bethesda, MD: AABB Press; 2007.