Inhaled nitric oxide (iNO) therapy improves gas exchange and lowers pulmonary vascular resistance (PVR) in diverse diseases. Most studies have demonstrated the utility of iNO during treatment with mechanical ventilation or with brief face mask administration. However, the ability of iNO to lower PVR by pulsed nasal cannula delivery is uncertain. Therefore, to determine whether iNO has potential for long-term treatment of chronic pulmonary hypertension, we studied the acute hemodynamic effects of pulsed nasal delivery of NO gas in children with pulmonary hypertension. Eight children underwent cardiac catheterization for the evaluation of pulmonary hypertension. Diagnoses included postoperative atrial septal defect (3) and ventricular septal defect (3), altitude related pulmonary hypertension (1) and cardiomyopathy (1). Ages ranged from 8 months to 14 years (median 25.5 months). iNO (20 ppm) and 21% FiO2 were administered by mask or pulsed nasal cannula in random order. iNO was delivered through one prong on a split nasal cannula using an oxygen pulsing device or via a standard resuscitation mask connected to a t-piece. All patients effectively triggered the iNO pulsing device. Pulsed nasal delivery of iNO lowered mean pulmonary artery pressure(PAP) and PVR as effectively as iNO delivered by face mask. Cardiac index (CI) did not change (Table, * p<0.05, value vs. BASELINE). Arterial blood gas tensions did not change. We conclude that pulsed nasal cannula iNO is effective in acute treatment of pulmonary hypertension. We speculate that pulsed nasal iNO can potentially be used for the long-term domiciliary treatment of pulmonary hypertension in children.

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