Red cell volume and cardiac output in anaemic preterm infants.

Abstract

To test the hypothesis that haemoglobin concentration is a poor predictor of benefit from transfusion in preterm infants, and that red cell volume is the most important indicator of anaemia, 24 preterm infants receiving red cell transfusions had red cell volume, haemoglobin concentration, and cardiac output measured before and after transfusion. Red cell volume was measured either using dilution of autologous fetal haemoglobin with donor adult haemoglobin, or with a new technique using biotin as a red cell label. The two techniques give similar results. Mean (SD) values before transfusion were 27-4 (13.3), and after transfusion 45 0 (13.7) mI/kg. Cardiac output was measured using imaging and Doppler ultrasonography, and fell with transfusion from mean 286 (121) to 251 (95.6) ml/kg/min. The red cell volume before transfusion correlated well with changes in cardiac output following transfusion, infants with a red cell volume before transfusion of less than 25 ml/kg showing a fall in cardiac output, and those with a red cell volume of greater than 25 ml/kg not showing a significant fall. There was no correlation between haemoglobin concentration, packed cell volume, or change in packed cell volume with changes in cardiac output after transfusion.A red cell volume of 25 ml/kg seems to be critical in preterm infants with anaemia, and infants with values below this are those most likely to benefit from transfusion.

In Which Neonates Does Early Recombinant Human Erythropoietin Treatment Prevent Anemia of Prematurity? Results of a Randomized, Controlled Study

“…Probably with preventive EPO administration the neonates would not need any transfusion, because the end goal of EPO thcrapy is to reduce transfusions as much as possible because of their side effects. Such a goal is attractive, because 3% of infants who undergo transfusion have adverse effects (7). In our study, one of the three neonates in the uncomplicated EPO group who received transfusions had two transfusions after the end of EPO treatment.…”

“…vcry small premature neonates are among the most common of all patient groups to undergo extensive transfusion and the number of blood transfusions given in neonatal intensive care units has increased as the surviv;il of vcry in~nia-turc infants has improved (6). Red ccll transfusion entails a considerable risk to snlall babies (7). Recently.…”

Hematocrit Correlates Well with Circulating Red Blood Cell Volume in Very Low Birth Weight Infants

“…Using a variety of methods for measuring RBC volume and for obtaining the blood samples, other investigators (9,10,(12)(13)(14) have detected a poor correlation between circulating RBC volume and HCT in VLBW infants. Reported correlation coefficients varied between 0.3 and 0.7.…”

“…Although circulating RBC volume is a more accurate indicator of total body oxygen delivery capacity than whole blood HCT or Hb concentration (9,10), HCT and Hb concentration are used clinically because they are quick, inexpensive, and analytically reliable. To understand the limitations of HCT as a guide to transfusion decisions, the relationship between HCT and circulating RBC volume in VLBW infants should be elucidated, and the sources of the previously reported poor correlation (9 -14) should be segregated into methodologic artifacts and genuine characteristics of preterm physiology.…”

Treatment with erythropoietin in neonatology

“…The non-physiological anaemia of the preterm infant, better known as the anaemia of prematurity (4-12 weeks after birth) appears mostly in preterm infants with very low birth weight (1,500 g or less) and is a time-limited, hyporegenerative, normocytic normochromic anaemia with decreased erythropoiesis in the bone marrow reflected in very low reticulocyte values in peripheral blood (under 3.0 %), while leukocyte and thrombocyte values are generally normal. (15)(16)(17) Haemoglobin concentration is under 70-100 g/L, haematocrit is under 0.30; the child also has clinical signs of anaemia such as poor weight gain, tiredness at feeding, tachypneas, dyspneas, tachycardia, apnoea attacks and metabolic acidosis. Hypoperfusion of the intestines can cause necrotizing enterocolitis, BDP treatment is slowed down, as well as closing of the ductus Botalli.…”