Carbon monoxide (CO) is produced by the oxidative degradation of haem and diffuses into the alveolar spaces. Oxidative stress and inflammation increase the rate of CO production and both of these are features of respiratory distress syndrome in very preterm infants. In such infants, increased end-tidal concentrations of CO, corrected for inhaled CO (ETCOc), have been found to be predictive of bronchopulmonary dysplasia which in turn is associated with brain pathology and poor neurodevelopmental outcome. Investigators in The Netherlands (Cornelie A Blok …