Inhaled NO and markers of oxidant injury in infants with respiratory failure.

Inhaled nitric oxide (iNO) is an effective adjunct in the treatment of infants with respiratory failure. Although there are clear benefits to this therapy, potential toxicity could result from reactive nitrosylated species. To evaluate whether iNO therapy is associated with increased serum markers of oxidative stress. Multiple markers were prospectively evaluated in the serum of term infants with severe respiratory failure treated with iNO for 1 to 72 hours. These were compared to those of patients exposed to greater than 80% oxygen for more than 6 hours and room air controls. After 24 hours of exposure, the iNO-treated infants had increased serum lipid hydroperoxides (LPO), protein carbonyls and nitrotyrosine residues as well as increased serum total glutathione (GSH) content. The increase in LPO peaked at 24 hours and correlated with the cumulative dose of iNO whereas other markers did not. The presence of chronic lung disease (CLD) did not correlate with serum markers of oxidative injury. In term infants with respiratory failure, prolonged iNO exposure is associated with a transient increase in markers of oxidative stress, but this finding does not appear to predict the development of CLD.