Lowering blood platelet transfusion threshold can prevent major bleeding in premature babies

Many premature babies are born with too few blood platelets, the cells that help blood to clot, and are given blood platelet transfusions to prevent major bleeding. But it has been unclear how low a baby's platelet counts need to be before a blood platelet transfusion should be given.

Now a study co-led by Oxford researchers, which included babies at the John Radcliffe Hospital, has found that, surprisingly, giving this transfusion when the baby's platelets are lower actually works better: babies given the transfusion when their platelet counts fell below 25 x109 per litre were less likely to die or suffer from major bleeding, compared to those who were given the transfusion when their platelet count was higher, at 50 x109 per litre. 

The results are published in the New England Journal of Medicine, and describe the results of the international PlaNet-2/MATISSE clinical study, which looked at platelet transfusions in premature babies over six years at 43 paediatric/neonatal units across the UK, Ireland and Netherlands: the study included 660 babies, making it the largest study of premature babies with very low blood platelet counts.  

One group of babies included in the study were either given the platelet transfusion when their platelet count fell below 50 while another group was given the transfusion when their platelet count fell lower, to 25.

The researcher found that giving the transfusion when babies' platelet counts fell below 25 rather than 50 would result in in seven fewer babies (out of every 100) suffering from major bleeding, or dying.  

Professor Simon Stanworth, Co-Chief Investigator and researcher at the Radcliffe Department of Medicine at Oxford University, said: "Studies like this are only possible with the huge support and dedication of parents and staff across many hospitals and in NHS Blood and Transplant, and with help from many colleagues in the Netherlands and Ireland." 

Prof Stanworth, who is also a Consultant Haematologist at the John Radcliffe Hospital in Oxford and NHS Blood and Transplant, added: "The findings have major implications for how neonatologists use platelet transfusions for sick premature babies with low platelets. We need to remember that platelet transfusions are biological products, and they do have risks. This study also raises questions about using platelet transfusions routinely in other patient groups with very low platelets."

Dr Anna Curley, Co-Chief Investigator for the study and consultant neonatologist in the Neonatal Intensive Care Unit at the National Maternity Hospital, Dublin, Ireland said: "Research is essential if we are to provide the best possible evidence-based care and improve outcomes for premature babies. I am very proud to have been part of the PlaNet-2 study, where the results will help improve how we treat babies with low platelets. This study was only possible because of the funding we received, the hard working clinical and research staff who took part and most importantly the parents who allowed their babies to take part in our study. I would like to thank the clinicians and families involved in the study and let them know that their efforts will make a real difference to the care of babies worldwide."

Doctor Andrew Cox, consultant neonatologist at East Lancashire Hospitals NHS Trust, said: "We often see premature babies in our unit with low platelets, and the result of the PlaNet-2 trial will guide us in managing these babies more safely and effectively. Babies and their families beyond those who so generously took part in the trial will benefit, and it is likely that more premature babies will survive because of them. This is a wonderful legacy, for which all those who care for sick babies should be thankful."

The study was funded by NHS Blood and Transplant (NHSBT), Sanquin Research, Amsterdam, and Addenbrooke's Charitable Trust Neonatal Breath of Life Fund.

It was supported by the NHSBT Clinical Trials Unit and was adopted on the NIHR portfolio of clinical trials.