Red blood transfusion in preterm infants: changes in glucose, electrolytes and acid base balance.

BACKGROUND

Preterm neonates comprise the most heavily transfused group of patients, and about 85% of extremely low birth weight newborns receive a transfusion by the end of their hospital stay. The aim of this study was to assess the possible metabolic effects of RBC transfusion on preterm infants, especially during the first 2 weeks of life, and its relation to blood volume.

MATERIALS AND

METHODS

This study was conducted on 40 preterm neonates with gestational age of less than or equal to 34 weeks. They received RBCs transfusion during first 2 weeks of life. Venous blood samples of infants were collected 2 to 4 hours before and 1 hour after the end of transfusion to evaluate hemoglobin (Hb) level, hematocrit, acid-base, electrolytes, and glucose status. Then, infants were classified into two main groups: those who received RBCs volume less than or 20 ml/kg and those who received RBCs volume more than 20 ml/kg.

RESULTS

Infants received a mean volume of 20.38 ± 3.2 ml/kg RBCs (range, 10.9 - 26.6 ml/kg) at a median age of 9.8 ± 3.6 days. After transfusion, a significant increase of mean Hb (P<0.001), mean Hct (P<0.001), pH (P<0.001), pO(2) (P<0.05), and a significant decrease of the pCO2 (41.46 ± 8.8torr vs 35.4 ± 9.34 torr; P<0.001) were observed. In addition, there was a significant increase of serum K(+) (P<0.001), and a significant decrease of Ca(+2) (P<0.001). A positive correlation was found between the K(+) intake and the changes of kalemia (r = 0.99; P = 0.00). Furthermore, we observed an inverse correlation between the patients' calcium intake and the changes of calcemia (r = -0.35; P = 0.02). On comparing the changes in clinical and biochemical variables between two groups after transfusion, we observed a significant increase in mean Hb and Hct associated with a significant decrease in mean serum Ca(+2) (P<0.001) in the group receiving the larger blood volume.

CONCLUSION

RBC transfusion was effective in improving anemia, oxygenation, increasing pH, and decreasing CO(2) and Ca(+2). However, from a more clinically relevant point of view, we demonstrated the development of hyperkalemia, especially in infants with a previously borderline hyperkalemia.