Nitric oxide levels in preterm and term infants and in premature infants with bacteremia

Objective: To determine the serum nitric oxide levels in healthy neonates and in infants with bacteremia. Methods: We performed a prospective study in a tertiary neonatal intensive care unit. The serum nitric oxide levels were measured in all infants at birth (basal) and in the infected neonates also on the first 2 days of bacteremia. Results: Thirty-three neonates (10 term, 23 preterm) were included. Eleven preterm infants (mean gestational age 27 weeks) had bacteremia. The main blood culture isolates included coagulase-negative staphylococci (n = 4), Klebsiella pneumoniae (n = 3), and Escherichia coli (n = 3). The serum nitric oxide levels increased during infection in 10 infants (p < 0.008). The mean nitric oxide level before infection was 44 μM and during infection 96 μM (p = 0.008). In the healthy babies, the mean nitric oxide level was 26 μM in those with a gestational age <27 weeks, 44 μM in those born between 28 and 36 weeks of gestation, and 63 μM in term infants. Conclusions: Bacteremic preterm infants produce significantly higher amounts of nitric oxide. The basal nitric oxide levels at birth may be correlated with gestational age.