Anaemia in the Premature Infant and Red Blood Cell Transfusion: New Approaches to an Age-Old Problem

Abstract

Opinion statementRed blood cell (RBC) transfusion is a common intervention in very preterm infants with variable utilisation between centres and individual clinicians. This variation likely reflects uncertainty about who, when and how much to transfuse. Most RBC transfusions are given in small volumes as "top-up" for anaemia or cumulative phlebotomy loss. Whilst the newly born infant may have a low haemoglobin (Hb) value, it is uncertain if this is of clinical or physiologic significance except at extreme values. Little attention has been given to the potentially favourable effect of RBC transfusion on oxygen kinetics, particularly in the interval after birth when the risk of hypoxic ischaemia is high. Later anaemia, at the time of likely Hb nadir, more typifies anaemia of prematurity. In this article, we will firstly review the conventional model of RBC transfusion based on haemoglobin [Hb] thresholds and secondly, we will propose an alternate, individualised, practice based on the oxygen physiology. This effectively reframes the potential role of RBC transfusion in the very preterm infant and demands a new generation of clinical trials.

Blood transfusion for anaemia of prematurity: Current practice in Australia and New Zealand

“…However, normative values for reticulocyte counts in preterm infants remain largely unknown and warrant further investigation. In Australasia, the lack of clarity about when to transfuse these infants adds urgency to the need for research into newer clinical adjuncts, such as the degree of tissue hypoxia detected by NIRS to determine timing and efficacy of transfusion for AOP …”

“…More recently, researchers have examined the clinical utility of the regional tissue oxygenation (rSO 2 ), measured non‐invasively by near‐infrared spectroscopy (NIRS), as an indicator of anaemia‐induced tissue hypoxia . As a mixed arteriolar, capillary and venular oxygenation index, rSO 2 may inform adequacy or otherwise of oxygen delivery relative to consumption at the tissue level.…”

Management of anaemia in pre‐term infants

“…The 2 hypothetical scenarios in Table highlight the limitation of Hb as a proxy for oxygen delivery (DO 2 , ml/kg/min). Furthermore, ‘adequacy’ of DO 2 must be considered in the context of oxygen consumption (VO 2 ) in a given infant at any given moment in time (Andersen et al , ). Crucially, in pre‐term infants, rates of oxygen consumption are dynamic and influenced by many factors, including post‐natal age, body temperature, pulmonary work of breathing and inflammatory process (e.g.…”

Cerebral oxygenation and cardiorespiratory stability following liberal transfusion in preterm neonates

“…Regional oxygenation (rSO 2 ) by near-infrared spectroscopy (NIRS) has the potential to inform vital organ oxygenation and has been advocated as a potential clinical adjunct to the current haemoglobin-based neonatal transfusion guidelines (1). Researchers have demonstrated that transfusion of red blood cells (RBCs) for anaemia of prematurity leads to increases in rSO 2 and/or decreases in fractional tissue oxygen extraction (FTOE) in the brain, kidney, gut and muscle up to 24 hours after transfusion (2)(3)(4).…”