Affiliations: Division of Neonatology, University of Siena, Siena, Italy
Abstract: In order to evaluate changes in the rheological properties of whole blood during the first days of extrauterine life, determinations of flow rate were carried out in 22 healthy full term newborn infants with weight appropriate for gestational age. At birth and on 4th day of life, flow rate was measured by the method of Reid et al. along with Ht, MCV, MCH, MCHC, Hb content, WBC, RBC and platelet count, plasma fibrinogen and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) and glutathione-reductase (GR), the main erythrocyte oxygen radical scavenger enzymes. Erythrocyte flow rate was significantly lower on 4th day than in cord blood. Fibrinogen plasma content significantly increased from birth to the 4th day and no significant differences were detected in the other data with the exception of MCV, which was higher in cord blood. GSH-Px values in cord and 4th day blood correlated positively with flow rate. A multiple regression analysis between flow rate in cord blood as dependent variable and other parameters evaluated in both cord and 4th day blood revealed two significant correlations: with GSH-Px (positively in both cord and 4th day blood), with GR (negatively in cord blood). The data suggest that the red cell antioxidant system could account for the rheological properties of whole blood during the first days of life.
