INHALED NITRIC-OXIDE AND HIGH-FREQUENCY OSCILLATORY VENTILATION IN PERSISTENT PULMONARY-HYPERTENSION OF THE NEWBORN

Inhaled nitric oxide (iNO) improves oxygenation in near-term and term newborns with persistent pulmonary hypertension of the newborn (PPHN), and decreases the need far treatment with extracorporeal membrane oxy genation. However, some patients with PPHN either do not respond or ha ve only transient improvements in oxygenation during iNO therapy. Extr apulmonary shunting associated with high pulmonary vascular resistance in PPHN can cause critical hypoxaemia; however, the syndrome of PPHN is often associated with severe parenchymal lung disease (e.g., meconi um aspiration pneumonitis, bacterial pneumonia, and surfactant deficie ncy) which causes intrapulmonary shunting. It is increasingly recogniz ed that the effective use of iNO requires adequate lung inflation to o ptimize delivery of the drug within the lung. High frequency oscillato ry ventilation (HFOV) causes safe and effective lung recruitment when an appropriate strategy is applied and has recently been shown to impr ove the response to iNO when parenchymal lung disease occurs in associ ation with PPHN. Conclusion Recent studies have shown that HFOV augmen ts the response to iNO in PPHN associated with meconium aspiration syn drome or diffuse parenchymal lung disease (pneumonia, respiratory dist ress syndrome). Suboptimal lung inflation compromises the efficacy of iNO in PPHN, and may in part explain the reported differences in iNO r esponse rates.