Background/Objectives: Acute hypoxemic respiratory failure (AHRF) is a frequent cause of pediatric ICU admission. Early treatment with inhaled nitric oxide (iNO) plus conventional mechanical ventilation (CMV) improves oxygenation, responsiveness being significantly influenced by alveolar recruitment level. High-frequency oscillatory ventilation (HFV) is conceptually very attractive as constant mean airway pressure optimizes lung recruitment; this could maximize iNO effects.