F101 Arch Dis Child Fetal Neonatal Ed: first published as 10.1136/adc.2002.019760 on 1 March 2004. Downloaded from PERSONAL PRACTICE Neonatal transfusion practice N A Murray, I A G Roberts ............................................................................................................................... Arch Dis Child Fetal Neonatal Ed 2004;89:F101–F107. doi: 10.1136/adc.2002.019760 Many previously widely accepted neonatal transfusion However, neither clinical situation is straight- forward to define. practices are changing as neonatologists become more aware of the risks to their patients of multiple blood product Tissue oxygenation Ensuring adequate tissue oxygen delivery transfusions. Recent literature and research on neonatal Tissue oxygenation is influenced by the concen- transfusion practice are here reviewed, and practical tration and type of haemoglobin (Hb), the guidelines and trigger thresholds for blood products concentration of 2,3-diphosphoglycerate within RBCs (both factors affect the Hb-oxygen dis- commonly used in neonatal medicine are proposed. sociation curve and thus the oxygen unloading ........................................................................... capacity of the blood), and the cardiopulmonary function of the neonate. Apart from Hb concen- ick neonates are one of the most heavily tration, none of these variables are easily transfused groups of patients in modern measurable in everyday neonatal practice. In Smedicine. However, despite considerable addition, assuming optimised cardiopulmonary research, most neonatal transfusion practice function during intensive care, apart from alter- remains opinion based rather than truly evidence ing Hb concentration by transfusion (and based. Most neonatologists would not prescribe thereby Hb type and 2,3-diphosphoglycerate drugs to their patients unless there was a concentration by exchanging HbF for HbA reasonable expectation of benefit. RBCs), little can be done to influence these Unfortunately, this rigour does not translate to variables on an hour to hour or day to day basis. the prescription of blood products, and as a result Thus RBC transfusion remains the only ‘‘haema- there exists a diversity of opinion and practice tological’’ treatment option available that has the copyright. between different clinicians1 and different insti- potential to significantly influence tissue oxygen tutions.2–6 Clearly the administration of blood delivery. However, the question remains how to products conveys a finite risk of transmitting recognise when a neonate is developing Hb potentially serious infections7–9 and is not with- limited oxygen unloading capacity to the tissues out risk and cost.78 It therefore remains a and how to measure this accurately in everyday continuing task to define and refine the most practice? clinically appropriate protocols for blood product use in neonates, within the constraints of the Methods of assessing tissue oxygenation available evidence. With these goals in mind this Peripheral fractional oxygen extraction (FOE) paper reviews recent literature and research on Direct measurement of tissue oxygenation is not possible. However, surrogate measures have been neonatal transfusion practice and proposes prac- 12 tical transfusion guidelines and trigger thresh- attempted. Recently, Wardle et al measured olds for commonly used blood products in peripheral FOE by near infrared spectroscopy as http://fn.bmj.com/ neonatal medicine. a surrogate measure of the adequacy of tissue oxygen delivery in 74 neonates , 1500 g under- going standard neonatal care. High peripheral RED BLOOD CELLS FOE (. 0.47) was taken as a cut off point Packed red blood cells (RBCs) are the most suggesting inadequate tissue oxygen delivery and common blood product administered to sick thereby the potential for inadequate tissue neonates. Many previous studies (reviewed in oxygenation. This parameter was used as an on September 29, 2021 by guest. Protected refs10 11) have attempted to define their optimal RBC transfusion trigger in 37 neonates, with the use in neonates. However, rapidly changing remaining 37 neonates receiving RBC transfu- patient populations and characteristics over sion guided by a conventional Hb based protocol. the last decade, coupled with the introduction Although there was a trend towards fewer RBC of increasingly rigorous transfusion protocols, transfusions in the FOE group, this was not See end of article for have reduced the relevance of much of this significant. However, neonates in the FOE group authors’ affiliations ....................... previous work to modern neonatal practice. had lower median Hb during the study, and time Progress in RBC transfusion practice therefore Correspondence to: requires a fundamental re-evaluation of its basic Dr Murray, Imperial aims. ................................................... College, Faculty of Medicine, Hammersmith At the most basic level, RBC transfusions are Abbreviations: BCSH, British Committee for Standards in Campus, Hammersmith required for two reasons: Haematology; CLD, chronic lung disease of prematurity; Hospital, Du Cane Road, DIC, disseminated intravascular coagulation; FFP, fresh London W12 0NN, UK; N to ensure adequate tissue oxygenation during frozen plasma; FOE, fractional oxygen extraction; HAS, [email protected] intensive care periods human albumin solution; Hb, haemoglobin; IVH, intraventricular haemorrhage; NEC, necrotising Accepted 12 July 2003 N after intensive care, to treat clinically signifi- enterocolitis; NHI, normal human immunoglobulin; RBC, ....................... cant symptomatic anaemia red blood cell; rhEPO, recombinant human erythropoietin www.archdischild.com F102 Murray, Roberts Arch Dis Child Fetal Neonatal Ed: first published as 10.1136/adc.2002.019760 on 1 March 2004. Downloaded from to first transfusion from study entry was also longer. No Guidelines for transfusion of RBCs difference in major neonatal complications was seen between Taking into consideration the available evidence, we use the the two groups, suggesting that no clinical compromise following RBC transfusion practice in neonates. occurred in the neonates in the FOE group. Interestingly, two thirds of transfusions in the FOE group were given because of Packed RBC product clinical concerns about low Hb or symptoms and not because The British Committee for Standards in Haematology (BCSH) of high FOE. Thus, this method of assessing trigger thresh- Transfusion Task Force23 recommends the following. olds for RBC transfusion in preterm neonates deserves further assessment, as sticking closely to high FOE as a N Components for transfusion in utero or to children under transfusion trigger may prove to be a practical method to 1 year of age must be prepared from donors who have further reduce RBC transfusions and donor exposure without given at least one donation within the previous two years adversely affecting outcome. that was negative for all mandatory microbiological markers. Capillary whole blood lactate N Dedicating aliquots from a single donation to allow Lactate concentration has also been assessed as an indicator sequential transfusions from the same donor for neo- of tissue oxygenation and/or the need for RBC transfusion.13– nates/small children who are likely to be repeatedly 16 In the intensive care period, lactate concentrations are transfused is considered good practice. highly variable, probably reflecting variations in tissue N Components transfused in the first year of life should be perfusion rather than Hb limited oxygen unloading capacity cytomegalovirus seronegative (since November 2001 all to the tissues. Therefore, during intensive care, lactate cellular blood products in the United Kingdom have been concentrations are not useful in deciding the need for RBC leucocyte depleted before hospital issue and are widely transfusion. In stable neonates, these concentrations have regarded as cytomegalovirus safe; nevertheless, in the been shown to decrease after RBC transfusions given for 13 15 16 absence of controlled trials, the BCSH continues to ‘‘symptomatic’’ anaemia. However, even in stable recommend cytomegalovirus negative products for preterm neonates, lactate concentrations show considerable infants). variation during a 24 hour period,13 and before transfusion they do not correlate with Hb or packed cell volume.13 Thus, For a full discussion of recommendations for blood peripheral blood lactate concentrations may be useful in the components for use in the newborn, the reader is referred overall assessment of tissue perfusion/oxygenation, but on to the BCSH guidelines web site.23 their own are not a reliable indicator of the need for RBC transfusion. Dose (volume) of RBCs In summary, with currently available techniques, there is In preterm neonates the small amount of research available no practical method applicable to everyday neonatal practice suggests that large volume (20 ml/kg) RBC transfusions lead copyright. that accurately and reproducibly assesses tissue oxygenation. to larger rises in Hb and fewer overall transfusions than small volume transfusions (10 ml/kg).24 This volume of packed Trends in clinical practice RBCs is well tolerated in the vast majority of preterm As high quality methods for assessing tissue oxygenation are neonates.24 not available, observational clinical studies of RBC transfu- sion practice represent the best available evidence to guide Triggers for RBC transfusion future developments. Over the past 15 years, a number of Adhering