Partial liquid ventilation and nitric oxide in congenital diaphragmatic hernia

Purpose: In congenital diaphragmatic hernia (CDH) there is immature lung development with a resulting clinical picture of pulmonary hypoplasia, surfactant deficiency, and pulmonary hypertension. Pulmonary hypoplasia and surfactant deficiency both have been successfully treated using partial liquid ventilation (PLV). Pulmonary hypertension associated with CDH has proven difficult to treat, but inhaled nitric oxide, which is a potent highly selective pulmonary vasodilator, may have potential. The aim of this study was to assess PLV in CDH and to document the effect of nitric oxide when administered through perfluorocarbon. Methods: This study using the lamb CDH model consisted of two groups; a conventional mechanically ventilated (CMV) group and a PLV group. At 1 and 3 hours, nitric oxide (80 ppm) was given for 15 minutes. Data collected included blood gases, pulmonary function tests, pulmonary and systemic blood pressure. Results: After 30 minutes of ventilation, blood gases in the PLV group were all significantly improved (P < .001): pH, CMV 6.92 ± 0.15 versus PLV 7.24 ± 0.11; PCO₂, CMV 139 ± 26 mmHg versus PLV 52 ± 11 mmHg; PO₂, CMV 26 ± 15 mmHg versus PLY 184 ± 60 mmHg. In addition, there was a significant increase in dynamic compliance and a reduction in pulmonary hypertension. Nitric oxide was only efficacious in the PLY group, causing a further increase in oxygenation and a decrease in pulmonary hypertension. These effects were reversed when the nitric oxide was stopped. Conclusion: This study shows that PLV both improves gas exchange and pulmonary mechanics in CDH and allows the effective delivery of nitric oxide to reduce the pulmonary hypertension associated with CDH.