Evidence
Alert

Age of stored blood used for transfusions in critically ill children doesn’t affect outcomes

Using more recently-collected red blood cells for transfusions does not reduce organ dysfunction, infection or risk of death in critically ill children, compared with blood that has been stored for longer.

This large, international trial included more than 1,500 children in paediatric intensive care units.

The study provides robust evidence to support the continued practice of using the oldest compatible red blood cells within their use-by date. This is done to minimise the amount of donated blood becoming out of date before it is used, reducing waste and saving money. In the UK, blood can be stored for a maximum of 35 days after it has been donated.

Why was this study needed?

Blood transfusion is common in clinical practice. About 2.5 million units of blood are transfused in the UK each year. Most hospitals use blood closest to its use-by date first, to minimise waste. This means that most transfusions already use ‘older’ stored blood. But red blood cells change during storage, and some studies have suggested that transfusions using older stored blood might be associated with poor outcomes.

For critically ill adults and premature babies recent large trials have shown that the use of older blood is safe. But no studies have looked at the effects of the age of transfused blood in critically ill children.

This study aimed to compare outcomes after transfusions of blood selected according to usual practice, with transfusions using fresher red blood cells stored for a maximum of seven days.

What did this study do?

The ABC-PICU trial was carried out in 50 centres in five countries (US, Canada, France, Italy and Israel). A total of 1,538 critically-ill children aged between three days and sixteen years was recruited. Half were randomly assigned to the fresh red blood cell group (using blood stored for a median of five days [interquartile range 4–6 days]). The other half were assigned to the usual practice group (using the oldest compatible blood available, median storage duration 18 days [interquartile range 12–25 days]).

Participants were followed up for 28 days, or until hospital discharge or death.

Reason for ICU admission, age, and amount of blood transfusion did not differ between groups. As this was a large, robust study that included patients similar to those in paediatric intensive care units in the UK, the findings should be applicable.

What did it find?

  • The age of stored blood made no significant difference to the development of new or progressive multiple organ dysfunction. This occurred in 20.2% (147/728) patients of the fresh red blood cell group, and in 18.2% (133/732) of the usual practice group (unadjusted absolute risk difference [aRD] 2.0%, 95% confidence interval [CI] -2.0% to 6.1%).
  • There was no difference in the prevalence of sepsis between the groups, affecting 25.5% (160/619) of the fresh blood group, compared with 25.3% (154/608) patients of the usual practice group (unadjusted aRD 0.5%, 95% CI ‑4.4% to 5.4%).
  • There was also no difference in the numbers who died within 90 days or in intensive care between the groups.

What does current guidance say on this issue?

The Joint United Kingdom (UK) Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee produces guidelines for the preparation and storage of blood products in the UK.

The guideline for blood transfusion services states that red blood cells can be stored for a maximum of 35 days. It doesn’t recommend whether older or fresher blood products should be used first.

What are the implications?

This study did not show any benefit of using fresh red blood cells for transfusions in critically ill children. It supports the current practice of using the oldest compatible stored blood products first.

However, the median length of storage of red blood cells for the usual practice group was only 18 days. This means that the trial was unable to determine whether blood stored for the maximum length allowable in the UK of 35 days might influence clinical outcomes.

Citation and Funding

Spinella PC, Tucci M, Fergusson DA et al. Effect of fresh vs standard-issue red blood cell transfusions on multiple organ dysfunction syndrome in critically ill pediatric patients: a randomized clinical trial. JAMA. 2019;322(22):2179–90.

Bibliography

JPAC. Guidelines for the blood transfusion services. Chapter 7.5: red cells, leucocyte depleted. 8th edition. London: The Stationery Office; 2013.

NHS Blood and Transplant. Transfusion FAQs. Bristol: NHS Blood and Transplant; accessed January 2020.

NHS website. Blood transfusion. London: Department of Health and Social Care; 2018.

NICE. Blood transfusion. NG24. London: National Institute for Health and Care Excellence; 2015.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

All red blood cells used in the trial were leucocyte depleted (i.e. white blood cells were removed).

 

Commentaries

Expert commentary

It is well known that red blood cells undergo metabolic and structural changes during storage. The results of large, non-randomised studies comparing ‘fresh’ with stored blood raised concerns that patients may be harmed by the transfusion of older red blood cells.

However, several large multicentre randomised clinical trials in clinical settings including cardiac surgery, critical care, and premature infants found no differences in morbidity or mortality between patients who received fresher blood compared to older blood or blood issued as standard care.

This international multicentre randomised trial in a previously unstudied population of critically ill paediatric patients replicates those findings. The results of these trials, while not excluding that the transfusion of old blood may have a small adverse effect on patient outcomes, provide reassurance that the current transfusion practice to issue the oldest blood units to minimise wastage is safe.

Mike Murphy, Professor of Blood Transfusion Medicine, University of Oxford; Consultant Haematologist, NHS Blood and Transplant and Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital

The commentator declares no conflicting interests