Alterations in pulmonary mechanics after transfusion in anemic preterm infants.

Pulmonary mechanics were studied in ten anemic preterm infants using an esophageal balloon and mask, before and after transfusion with 10 ml/kg of packed RBC. Their mean birth weight was 1212 +/- 323 g and gestational age was 29.27 +/- 2.4 wk. Transfusions were carried out at a mean postnatal age of 41.9 +/- 21.8 days. The mean Hct increased from 28 +/- 3.1 to 38.3 +/- 3.3%. Dynamic lung compliance decreased in all infants after transfusion. There was a 33.8% increase in resistance; the work of breathing increased after transfusion. These changes might be due to volume overload or increased lung water content.