Favorable response of Eisenmenger syndrome to inhaled nitric oxide during pregnancy

Our goal was to evaluate the effectiveness of therapy with a specific pulmonary vasodilator, nitric oxide, in a woman with Eisenmenger syndrome during pregnancy.

Eisenmenger syndrome consists of a congenital communication between the systemic and pulmonary circulation with secondary pulmonary hypertension causing reversal of flow through the shunt. Maternal morbidity is approximately 50% with the greatest risk of death being in the peripartum period. Pharmacologic therapy to relieve worsening pulmonary hypertension is confounded by the undesired effects of vasodilators on the systemic circulation. Therapy with a specific pulmonary vasodilator, nitric oxide, was attempted.

A 27-year-old woman with Eisenmenger syndrome at 36 weeks' gestation was treated with inhaled nitric oxide during the second stage of labor and the postpartum period when she experienced progressive refractory hypoxemia. Administration of nitric oxide was followed by improved oxygenation and lowering of pulmonary artery pressures. A brief episode of methemoglobinemia responded to lowering of the nitric oxide concentration and administration of intravenous methylene blue. Nitric oxide was discontinued after 48 hours. The patient died 2 days later despite continued vasodilator therapy including intra-pulmonary artery prostacyclin.

Inhaled nitric oxide can be used to correct the hypoxemia of Eisenmenger syndrome. Nitric oxide inhalation is easily performed, and pulmonary vasodilatory effects commence within minutes after administration.