Occurrence of hyperoxia during iNO treatment for persistent pulmonary hypertension of the newborn: a cohort study

High concentrations of oxygen are often needed to optimize oxygenation in infants with persistent pulmonary hypertension (PPHN), but this can also increase the risk of hyperoxemia. We determined the occurrence of hyperoxemia in infants treated for PPHN. Medical records of infants ≥ 34 + 0 weeks gestational age (GA) who received inhaled nitric oxide (iNO) were retrospectively reviewed for oxygenation parameters during iNO therapy. Oxygen was manually titrated to target arterial oxygen tension (PaO₂) 10–13 kPa and peripheral oxygen saturation (SpO₂) 92–98%. The main study outcomes were the incidence and duration of hyperoxemia and hypoxemia and the fraction of inspired oxygen (FiO₂). A total of 181 infants were included. The median FiO₂ was 0.43 (IQR 0.34–0.56) and the maximum FiO₂ was 1.0 in 156/181 (86%) infants, resulting in at least one PaO₂ > 13 kPa in 149/181 (82%) infants, of which 46/149 (31%) infants had minimal one PaO₂ > 30 kPa. SpO₂ was > 98% in 179/181 (99%) infants for 17.7% (8.2–35.6%) of the iNO time. PaO₂ < 10 kPa occurred in 160/181 (88%) infants, of which 81/160 (51%) infants had minimal one PaO₂ < 6.7 kPa. SpO₂ was < 92% in 169/181 (93%) infants for 1.6% (0.5–4.3%) of the iNO time.

    Conclusion: While treatment of PPHN is focused on preventing and reversing hypoxemia, hyperoxemia occurs inadvertently in most patients.