Transfusion has been a mainstay of patient care for years. It is identified as the #1 procedure performed in hospitals.1 The development and ultimate use of specific blood components has provided ways to tailor transfusion therapy to the patient’s clinical needs. Processing and storage of blood components, although allowing for more targeted and diverse therapy, also may have its attendant downside. Transfusion, of course, is certainly life-saving in many instances, however recent attention and scientific literature have highlighted the increased risk-to-benefit ratio associated with transfusion. The so-called “storage lesion” may play a part in some transfusion-associated adverse events.
There are well-documented changes that occur in vitro with stored blood, RBCs in particular. These include decreasing concentration of 2,3-DPG, release of free hemoglobin, formation of microparticles, and nitric oxide interactions, all of which may be pro-inflammatory or pro-thrombotic, thus affecting oxygen delivery to the tissues. 2-5 These changes may progress over the lifetime of the RBC unit; shelf-life currently being 42 days, refrigerated.
These current studies have encouraged many clinicians to cast doubt on the ability of “older” RBCs to provide adequate oxygen delivery for anemic patients. The difficult questions remain and indeed are not limited to the following:
1) Is there clear clinical evidence that “older” RBCs do not provide adequate tissue oxygenation in vivo?
2) What is the definition of “old” blood? Is this >7days, >14days, >21 days or somewhere in between?
3) Is there some recovery of older RBCs once transfused into the patients’ intravascular milieu?
4) Are only certain patient populations with specific comorbid conditions at risk?
5) If indeed the storage lesion is clearly identified and defined, how will this affect acquisition of whole blood donations throughout our communities, i.e. what are the implications for stewardship and inventory management that would be necessary to maintain our blood supply?
6) How does one currently deal with the ethical issue of providing “younger” units to certain subsets of patients and not others?
Several prospective randomized controlled trials are currently proposed and enrolling patients to study these exact questions. 6-8 These are single-center as well as multicenter studies, involve adult and pediatric populations, and interestingly have varied definitions of the “age” of RBCs. Until the time that these studies report their findings, it is unlikely that a paradigm shift to “younger and fresher” blood is necessary or even possible.
At this particular point, I would agree with Dr. Dzik in his 2008 Transfusion Medicine article:
“Given the fragile balance of blood supply and demand on which modern medicine depends, the decision to reduce the period of allowable storage is an important one that deserves data generated from carefully designed prospective RCTs. Let us do the studies and find out the truth.” 9
In other words…soldier on and stay tuned…
- The 2009 National Blood Collection and Utilization Survey Report. http://www.aabb.org/programs/biovigilance/nbcus/Documents/09-nbcus-report.pdf
- Roback J Vascular effects of the red blood cell storage lesion. Hematology: Transfusion Medicine: Adverse Complications of Stored Blood, Amer Soc Hematol, 2011.
- Yazdanbakhsh K et al. Immunoregulatory effects of stored red blood cells. Hematology: Transfusion Medicine: Adverse complications of Stored Blood, Amer Soc Hematol, 2011.
- Hovav T et al. alteration of red cell aggregability and shape during blood storage. Transf, 1999; 39: 277.
- Mini-Symposium on RBC Storage. Transf, 2011; 51: 844-900.
- Paxton A RBC storage duration: Is older riskier? CAP Today, 2011; 25:10.
- Pavenski K et al. Red blood cell storage lesions and related transfusion issues: A Canadian Blood Services research and development symposium. Transf Med Rev, 2012; 26: 68.
- Van de Watering L (for the BEST Collaborative) Pitfalls in current published observational literature on the effects of red blood cell storage. Transf, 2011; 51: 1847.
- Dzik W Fresh blood for everyone? Balancing availability and quality of stored RBCs. Transf Med, 2008; 18: 260.
- Hovav, et al. Transfusion. 1999;39:277-281