Inhaled Nitric Oxide Is Associated with Improved Oxygenation in a Subpopulation of Infants with Congenital Diaphragmatic Hernia and Pulmonary Hypertension

Abstract

Objectives: 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.

Study design: 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 PaO₂ >20 mm Hg) or nonresponders. Baseline characteristics, echocardiograms and outcomes were compared between groups with Fisher exact tests and Mann-Whitney t tests, as appropriate.

Results: During the study period, 95 of 131 patients with CDH (73%) were treated with iNO. All patients with pretreatment echocardiograms (n = 90) had echocardiographic evidence of PH. Thirty-eight (40%) patients met treatment response criteria. Responders had significant improvements in PaO₂ (51 ± 3 vs 123 ± 7 mm Hg, P < .01), alveolar-arterial gradient (422 ± 30 vs 327 ± 27 mm Hg, P < .01), and PaO₂ to FiO₂ ratio (82 ± 10 vs 199 ± 15 mm Hg, P < .01). Nonresponders were more likely to have left ventricular systolic dysfunction (27% vs 8%, P = .03) on echocardiogram. Responders were less likely to require extracorporeal membrane support (50 vs 24%, P = .02).

Conclusions: 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.

Keywords: ECMO.