Pumpless arteriovenous extracorporeal membrane oxygenation: A novel mode of respiratory support in a lamb model of congenital diaphragmatic hernia

Background: Extracorporeal membrane oxygenation (ECMO) is commonly required in neonates with congenital diaphragmatic hernia (CDH) complicated by pulmonary hypertension (PH). ECMO carries significant risk, and is contraindicated in the setting of extreme prematurity or intracranial hemorrhage. Pumpless arteriovenous ECMO (P-ECMO) may represent an alternative for respiratory support. The present study summarizes our initial experience with P-ECMO in a lamb model of CDH.

Study design: Surgical creation of CDH was performed at 65-75days' gestation. At term (135-145days), lambs were delivered into the P-ECMO circuit. Three animals were maintained on a low-heparin infusion protocol (target ACT 160-180) and three animals were maintained with no systemic heparinization.

Results: Animals were supported by the circuit for 380.7 +/- 145.6h (range, 102-504h). Circuit flow rates ranged from 97 to 208ml/kg/min, with adequacy of organ perfusion demonstrated by stable serum lactate levels (3.0 +/- 1.7) and pH (7.4 +/- 0.3). Necropsy demonstrated no evidence of thrombogenic complications.

Conclusion: Pumpless extracorporeal membrane oxygenation achieved support of CDH model lambs for up to three weeks. This therapy has the potential to bridge neonates with decompensated respiratory failure to CDH repair with no requirement for systemic anticoagulation, and may be applicable to patients currently precluded from conventional ECMO support.