Expired nitric oxide in the newborn with high risk of perinatal infection.

The objective of this study is to determine expired nitric oxide (expNO) in the first 3 days of life in relation to: hours of life, gestational age, type of labor, and risk of perinatal infection. Our hypothesis has been that expNO increases in newborns with high risk of perinatal infection. Total expNO was measured in 166 newborns: 108 healthy (63 full-term and 45 preterm), 30 with low risk of perinatal infection, and 28 with high risk of perinatal infection treated with antibiotics but without positive hemoculture. Expired gas was collected using a face mask and NO concentration was determined by chemiluminescence. Total expNO neither correlated with gestational age, birth weight or serum NOx, nor changed after cesarean section, but was related to hours of life. Total expNO in the < or = 36-hour subgroups (median, interquartile range) was higher in the high-risk perinatal infection newborns ( n = 8; 5.33 (4.5-7.2) nL/min*Kg) than in healthy newborns ( n = 59; 4.13 (3.5-4.7) nL/min*kg) or low-risk perinatal infection newborns ( n = 18; 3.99 (3.4-4.7) nL/min*kg). In the 37 to 72-hour subgroups there were also differences between healthy newborns ( n = 49; 4.68 (4.1-5.3) nL/min*kg) or low-risk perinatal infection newborns on the one hand ( n = 12, 4.55 (3.9-5.2) nL/min*kg) and high risk perinatal infection newborns on the other ( n = 20; 9.69 (7.6-11.1) nL/min*kg). Then, total expNO increased in newborns with high risk of perinatal infection, regardless of hours of life.