Abstract
Mixing and transcapillary loss of the plasma label Evans blue was studied in 84 preterm and term neonates and equilibration of both Evans blue and 99m-Tc-labelled red blood cells (99m-Tc-RBC) was investigated in 35 severely sick neonates with informed consent of the parents. Blood samples were taken 5, 10, 20, 30 and 45 min after injection of the indicators. Mixing time of Evans blue was complete within 10 min in 76 out of 84 neonates. Mixing of 99m-Tc-RBC was delayed to 20-30 min in 14 out of 35 infants. Prolongation of mixing time was related to low blood pressure and to low peripheral blood flow (plethysmography). Disappearance rate of Evans blue increased with increasing blood volume and with decreasing pH. The disappearance rate averaged 17±9%/h in 21 neonates without serious disorder, 24±10%/h in 48 neonates with RDS (P<0.05) and 28±7 %/h in 15 neonates with septicaemia (P < 0.001). The ratio of the body haematocrit (RBC mass/blood volume) to the venous haematocrit averaged 0.85±0.04 in 35 neonates. This ratio tended to decrease in severely sick neonates. We conclude that both plasma and RBC indicators may yield incorrect results when only one label is used or when only one blood sample is taken after injection of the indicators.
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Linderkamp, O., Lorenzen, K., Schmid, C. et al. BLOOD VOLUME ESTIMATION IN NEONATES USING 99m-TC-LABELLED ERYTHROCYTES AND EVANS BLUE. Pediatr Res 22, 219 (1987). https://doi.org/10.1203/00006450-198708000-00036
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DOI: https://doi.org/10.1203/00006450-198708000-00036