Background: Extreme preterm neonates are at high risk for requiring blood transfusions, with rates over 90% in this population (6). Each transfusion exposes the infant to risks including metabolic (hypoglycaemia, hyperkalaemia, hypocalcaemia), immunologic (transfusion reactions, transfusion related acute lung injury (TRALI), immune mediated platelet destruction) and infectious (6). Phlebotomy losses are a significant contributor to early anaemia in this population. The largest single blood draw is generally at admission to the neonatal unit, when haemodynamic stability is key for optimal transition. Alternatively, new guidance from the American Academy of Paediatrics recommends taking admission samples (culture, FBC, biochemistry, CRP, Group and Direct agglutination test) from the umbilical cord1. Benefits of postnatal cord blood sampling include improved blood pressures and haemodynamic stability, higher haemoglobin at 24 hours and reduced vasopressor and erythrocyte transfusion requirements in the first week1. Bensouda et al have demonstrated superior sensitivity of umbilical cord blood culture to neonatal blood culture, postulated to be secondary to greater volume samples 2. We wanted to assess the potential impact of this practice on our own extreme preterm population. Method: All infants under 28 weeks of gestation admitted to a UK tertiary neonatal unit over a 12-month period were included. We estimated admission bloods (culture, FBC, CRP, Blood group & DAT, biochemistry) to be a minimum of 2.5ml. We looked at phlebotomy loss as a percentage of circulating blood volume (80ml/kg)2 and need for transfusion in first week of life. We also calculated the volume of blood taken at admission as ml/kg to allow this to be quantified relative to our standard blood transfusion dose of 15ml/kg. Results: 74 babies included with birth weight ranges 351g – 1220g. Admission bloods comprised 2.6 – 8.9% of infants' circulating blood volume (CBV), mean 3.9ml/kg (range 2.1 – 7.1ml/kg). There was a statistically significant correlation between the percentage of CBV taken at admission and transfusion requirement in the first week of life (p = 0.001). All below 25 weeks required transfusion in the first week. Overall, 53% of survivors beyond 24 hours (excluding babies with Grade 3-4 IVH) were transfused in the first week of life, with an average Haemoglobin drop of 20% at day 7 (despite transfusion). (image) Conclusion: Standard admission bloods comprise a significant volume in the extreme preterm population, with a mean of 3.9ml/kg. For every 3.8 extreme preterm infants admitted to our unit, we take the equivalent of one 15ml/kg blood transfusion on admission bloods alone. Taking these samples from the cord will reduce phlebotomy losses which may then reduce the need for transfusion and improve haemodynamic stability at the time of transition. Evidence exists of feasibility and validity, with endorsement from national bodies such as the AAP1,3,4,5. Designing QI projects based on these recommendations and exploring their potential to reduce transfusions could benefit our patients.
Bradley et al. (Thu,) studied this question.