PT - JOURNAL ARTICLE AU - Laura K Fredrickson AU - Edward F Bell AU - Gretchen A Cress AU - Karen J Johnson AU - M Bridget Zimmerman AU - Larry T Mahoney AU - John A Widness AU - Ronald G Strauss TI - Acute physiological effects of packed red blood cell transfusion in preterm infants with different degrees of anaemia AID - 10.1136/adc.2010.191023 DP - 2011 Jul 01 TA - Archives of Disease in Childhood - Fetal and Neonatal Edition PG - F249--F253 VI - 96 IP - 4 4099 - http://fn.bmj.com/content/96/4/F249.short 4100 - http://fn.bmj.com/content/96/4/F249.full SO - Arch Dis Child Fetal Neonatal Ed2011 Jul 01; 96 AB - Objective The safe lower limit of haematocrit or haemoglobin that should trigger a red blood cell (RBC) transfusion has not been defined. The objective of this study was to examine the physiological effects of anaemia and compare the acute responses to transfusion in preterm infants who were transfused at higher or lower haematocrit thresholds. Methods The authors studied 41 preterm infants with birth weights 500–1300 g, who were enrolled in a clinical trial comparing high (‘liberal’) and low (‘restrictive’) haematocrit thresholds for transfusion. Measurements were performed before and after a packed RBC transfusion of 15 ml/kg, which was administered because the infant's haematocrit had fallen below the threshold defined by study protocol. Haemoglobin, haematocrit, RBC count, reticulocyte count, lactic acid and erythropoietin were measured before and after transfusion using standard methods. Cardiac output was measured by echocardiography. Oxygen consumption was determined using indirect calorimetry. Systemic oxygen transport and fractional oxygen extraction were calculated. Results Systemic oxygen transport rose in both groups following transfusion. Lactic acid was lower after transfusion in both groups. Oxygen consumption did not change significantly in either group. Cardiac output and fractional oxygen extraction fell after transfusion in the low haematocrit group only. Conclusions These study's results demonstrate no acute physiological benefit of transfusion in the high haematocrit group. The fall in cardiac output with transfusion in the low haematocrit group shows that these infants had increased their cardiac output to maintain adequate tissue oxygen delivery in response to anaemia and, therefore, may have benefitted from transfusion.