In vitro effect of furosemide on the chemiluminescence of polymorphonuclear neutrophils in preterm infants.

We tested the hypothesis that the phagocytic activity of polymorphonuclear neutrophils (PMNs) of neonates is more sensitive to furosemide (FU) in vitro than that of adults. Phagocytosis was monitored by chemiluminescence of PMNs in cord blood of full-term (n = 10) and preterm (n = 8) neonates in the presence of 0, 6, 9, and 12 micrograms/ml of FU. Venous blood from adults (n = 10) was used for comparison. Random motility and chemotaxis were also determined in the three groups. The peak chemiluminescence of PMNs in preterm neonates was significantly decreased at a FU concentration of either 6, 9, or 12 micrograms/ml when compared to full-term infants. In contrast, no difference was observed between full-term infants and adults. Random motility and chemotaxis were comparable in all groups, regardless of the FU concentration. The results of this study suggest that preterm infants may be more sensitive to FU, as indicated by the adverse effect of this drug on chemiluminescence activity of their PMNs, in vitro.