The Sydney Morning Herald and Newcastle Herald have recently published coverage of a retrospective 10-year Hunter New England Health observational study involving more than 20,000 blood transfusions, which concluded that patients who receive blood older than 14 days are more likely to develop sepsis. The researchers have recommended a ban on blood older than 35 days. At this stage, this research has not been published or peer reviewed, except as an abstract for the 52nd American Society of Haematology Annual Meeting (4-7 December 2010, Orange County Convention Centre, Orlando, Florida) in the 19 November 2010 edition of Blood (1).
It is well documented that red cells undergo numerous, complex physical and chemical changes during refrigerated storage which impact on their function and survival. Although much is known about the “red cell storage lesion”, there is still a lot that is not well understood. In particular, the clinical relevance of these changes is not clear, prompting significant research and debate in this area.
Whilst a number of clinical studies undertaken to date suggest that transfusion of older red cells is associated with poorer outcomes for patients compared with fresher red cell units, particularly in certain patient groups, other studies have not supported these findings. Additionally, most of the studies have been retrospective observational studies, not specifically designed to address the question of age of blood at transfusion, with multiple confounding variables to consider.
A number of prospective, randomised controlled trials are, however, currently underway overseas to address this question, the results of which should be available in 2012. The Blood Service is working closely with other international blood services to monitor and contribute to research in this area.
The age at which blood components are transfused is dependent upon the age at which they are supplied by the Blood Service as well as hospital and laboratory inventory management practices and clinical transfusion practice.
In turn, the age at which red cell components are supplied by the Blood Service is directly influenced by the clinical demand for red cells, inventory holdings and donor attendance patterns.
Monitoring and improving the age at which blood is supplied has been a priority for the Blood Service for some time. The average age of red cells supplied by the Blood Service is currently less than 8 days, noting the internationally accepted 42 day shelf-life for red cells. There is, however, a delicate balance which must be maintained between having sufficient inventory to meet clinical demand but not having too much such that it negatively impacts on the age profile of the inventory and, hence, age at supply.
The Blood Service has implemented a number of measures over the last couple of years, including the following:
Supporting clinicians and transfusion laboratories:
1. Supporting the optimisation of inventory management practices within hospitals and transfusion laboratories, including balancing sufficiency of supply to meet clinical demand against the desirability of not having too much stock such that the age profile of the inventory is negatively impacted or that will result in unnecessary wastage.
2. Promoting the appropriate use of blood components.
3. Supporting and contributing to related research.
4. Actively engaging with the broader clinical community on this issue.
Adapting our inventory practices:
5. Implementation of ‘patient-focused’ supply planning (i.e. “aligning supply with demand”).
6. Regular review of red cell issue policies and procedures to ensure emerging evidence that particular patients may benefit from the provision of fresher red cells is taken into consideration.
7. Statistical supply forecasting to enable timely adjustment of collection and production activities in response to fluctuations in clinical demand.
8. Use of planning strategies to align inventory blood group mix with patient need.
9. Use of a national inventory framework and the setting of upper and lower limits for red cell inventory by ABO and Rh (D) blood group (i.e. inventory sufficiency bands) to drive the average age at supply target.
10. Optimisation of inventory management practices.
11. Deployment of temporary strategies during periods of high inventory levels. These include:
• selective use of a “last-in-first-out” (LIFO) issue policy for particular blood groups e.g. B and AB when inventory exceeds target levels
• quarantining of red cells greater than 28 days old when inventory exceeds target levels
• changes to the age mix of red cells supplied to transfusion laboratories
Adapting our product:
12. Introduction of measures to ameliorate the storage lesion. Strategies to date include implementation of leucodepletion of all red cells and platelets, evaluation of alternative blood storage bags and options for blood components transport and storage.
The Blood Service supports the need for further data, including carefully designed, prospective controlled trials, to determine whether there are any patient groups who may benefit from the provision of fresher red cells; and will continue to closely monitor the discussions and debate and actively engage with the broader clinical community on this issue.
Reference
1. O'Mara SK et al. Blood Transfusion Increases Hospital Acquired Septicaemia. Blood (ASH Annual Meeting Abstracts) 2010; 116: Abstract 3346.
