[A study of the perfusion of the ventilated alveolar areas in hyaline membrane disease].

Thirty-three neonates presenting with hyaline membrane disease were investigated with simultaneous measurements of PACO2 and PaCO2, in order to establish the percentage (q) of the ventilated alveolar areas with little or no perfusion. Results show that during the acute phase of the disease, mean values for q are 40%. Highest figures are related with the most severe distress. In such cases, major pulmonary hypoperfusion is associated with extrapulmonary right to left shunts, as shown by a PO2 gradient between a pulmonary vein and the aorta. Later on, q values improve progressively. The importance of the reduction of the perfusion of the ventilated alveolar areas and its hemodynamic consequences suggest that in severe cases with hyaline membrane disease a pulmonary vasodilatator treatment could be prescribed, before the stage of refractory hypoxemia.