Abstract

The results of mechanical ventilation for severe hyaline membrane disease (HMD), and the changes in technique which took place, during the 6-year period 1967-72 are described. A pilot study of the effect of hydrocortisone among the most severely affected infants showed no benefit. After the introduction at the beginning of 1970 of a regimen for ventilating the infants at low peak airway pressures, slow respiratory frequencies, and high inspiration: expiration ratios, there was a sudden increase in survival rate which was largely accounted for by a reduction in the incidence of bronchopulmonary dysplasia. Evidence is presented that in infants with HMD mechanical factors are more important than oxygen toxicity in the pathogenesis of this condition.