[Experimental studies on extracorporeal membrane oxygenation (ECMO) perfusion for respiratory insufficiency...

Some types of neonatal respiratory insufficiency may be associated with severe pulmonary hypertension. This paper evaluates two methodologies of ECMO perfusion in the treatment of such serious respiratory insufficiency. Pulmonary hypertension was prepared in dogs by administering small pieces of gelatin sponge into the main pulmonary artery. The two methodologies of perfusion were venoarterial bypass (VAB) and venovenous bypass (VVB). Prior to ECMO perfusion, oxygen supplementation during perfusion and hemodynamics were examined. Oxygen supplementation was satisfactory in both VAB and VVB. With VAB, the mean pulmonary artery pressure (mPAP) was significantly dropped from 33.8 +/- 3.1 mmHg to 28.4 +/- 6.2 mmHg, the pulmonary blood flow (PBF) being significantly declined from 1.39 +/- 0.21 L/min to 1.07 +/- 0.15 L/min. With VVB, mPAP was significantly dropped from 33.9 +/- 6.2 mmHg to 29.1 +/- 5.1 mmHg, the pulmonary vascular resistance (PVR) being significantly decreased from 1983.1 +/- 656.0 dynes.sec.cm-5 to 1740.4 +/- 635.9 dynes.sec.cm-5. It is considered that VAB renders PBF decline, which induces a drop in PAP, while VVB accelerates a flow of well-oxygenated blood in the pulmonary artery, which results in a decline in PVR and then a drop in PAP. VVB as well as VAB is useful in the treatment of neonates with respiratory insufficiency who present with pulmonary hypertension.