18 BLOOD VOLUME OF PRETERM NEONATES DURING FLUID RESTRICTION

Abstract

Fluid restriction in neonates reduces the incidence of patent ductus arteriosus and introcranial hemorrhage, enhances the elimination of excess lung water, but may cause hypovolemia with impaired renal and cerebral blood flow. We studied changes in blood volume (BV) during a loss of 10% of body weight in 10 AGA infants of 750-1500g after birth, at the time of minimal weight (3.2±1.3d) and when birth weight was regained (11±3d). Plasma volume (PV) was measured by the Evans Blue dilution technique, BV and RBC mass were calculated from PV and venous HCT. Results (mean±SD; *p<0.05) are given in the table: When weight decreased by 10%. BV decreased by 7.5%. This reduction of BV was not associated with hypotension or oliguria. It may not increase the risk of hypoxic ischemic encephalopathy. Amarked fall in RBC mass and O2 capacity, despite substitution of sampled RBC's, may be of clinical relevance. To maintain RBC mass, additional RBC transfusion appears necessary.