Inhaled nitric oxide and gentle ventilation in the treatment of pulmonary hypertension of the newborn — A single-center, 5-year experience

Objective. To evaluate the effect of inhaled nitric oxide (INO) in pulmonary hypertension of the newborn (PH) in a single center over 5 years using gentle ventilation (GV), without hyperventilation or induced alkalosis. Methods: Data from 229 consecutive infants with PH of varied etiology treated with INO and GV, and from 67 infants with meconium aspiration syndrome (MAS) and primary PH (PPHN) treated with GV alone were reviewed over a 5-year period (86% outborn). INO was initiated at 25 ppm when PH and severe hypoxemia persisted despite maximal optimal ventilation. Hyper-ventilation or systemic alkalosis were not attempted. Results: Mean duration of ventilation was 9.9 ± 14 days (median 6.5 days). Average mean airway pressure (MAP) dropped from 17.7 ± 4.3 cm H₂O at the referral hospital to 13.2 ± 2.5 cm H₂O (p < 0.001) following admission to our unit using conventional settings and GV, before starting INO. Mean oxygenation index (OI) dropped from 46.8 ± 24.5 to 22.7 ± 21.4 within 24 hours of INO therapy (p < 0.001). Infants with higher baseline pH and lower baseline OI responded better to INO (p < 0.02). Overall survival was 72%. Patients with MAS and PPHN had the best response, 92% survived and there was a 46% reduction in need for extracorporeal membrane oxygenation (ECMO) compared to historical pre-INO period controls (23.9% vs. 12.8%, p < 0.01). In the infants treated with GV alone, the MAP dropped from 17.2 ± 4.3 cm H2O at the referral hospital to 12.6 ± 2.4 after GV was started in our unit. Conclusions: We conclude that INO is an effective and well-tolerated therapy for PH in infants receiving GV.