<p><strong>OBJECTIVES: </strong>To determine which patients with congenital diaphragmatic hernia (CDH) and pulmonary hypertension (PH) benefit from inhaled nitric oxide (iNO) treatment by comparing characteristics and outcomes of iNO responders to nonresponders.</p>

<p><strong>STUDY DESIGN: </strong>We performed a retrospective chart review of infants with CDH treated at our center between 2011 and 2016. In a subset of patients, iNO was initiated for hypoxemia or echocardiographic evidence of extrapulmonary right to left shunting. Initial post-treatment blood gases were reviewed, and patients were classified as responders (increased PaO &gt;20&nbsp;mm Hg) or nonresponders. Baseline characteristics, echocardiograms and outcomes were compared between groups with Fisher exact tests and Mann-Whitney t tests, as appropriate.</p>

<p><strong>RESULTS: </strong>During the study period, 95 of 131 patients with CDH (73%) were treated with iNO. All patients with pretreatment echocardiograms (n&nbsp;=&nbsp;90) had echocardiographic evidence of PH. Thirty-eight (40%) patients met treatment response criteria. Responders had significant improvements in PaO (51&nbsp;±&nbsp;3 vs 123&nbsp;±&nbsp;7&nbsp;mm Hg, P &lt; .01), alveolar-arterial gradient (422&nbsp;±&nbsp;30 vs 327&nbsp;±&nbsp;27&nbsp;mm Hg, P &lt; .01), and PaO to FiO ratio (82&nbsp;±&nbsp;10 vs 199&nbsp;±&nbsp;15&nbsp;mm Hg, P &lt; .01). Nonresponders were more likely to have left ventricular systolic dysfunction (27% vs 8%, P&nbsp;=&nbsp;.03) on echocardiogram. Responders were less likely to require extracorporeal membrane support (50 vs 24%, P&nbsp;=&nbsp;.02).</p>

<p><strong>CONCLUSIONS: </strong>iNO treatment is associated with improved oxygenation and reduced need for ECMO in a subpopulation of patients with CDH with PH and normal left ventricular systolic function.</p>