Prolonged Alteration of Lung Mechanics in Kyphoscoliosis by Positive Pressure Hyperinflation1,2

The effects of a short period of large inflation pressures, delivered by intermittent positive pressure devices, on the abnormal lung mechanics of patients with kyphoscoliosis were studied. Their chronically decreased lung compliance was, on the average, increased by 70 per cent by this procedure and this increase was maintained for as long as 3 hours. Lung tissue resistance, but not the Plethysmographic airway resistance, also decreased after the hyperinflation. The large increases in lung compliance, without correspondingly large increases in functional residual capacity, suggested that a reorientation of alveolar surface forces might have been responsible for this phenomenon, although expansion of collapsed air spaces could not be excluded. The accompanying decreases in work of breathing after the brief period of hyperinflation suggest that this procedure might be of clinical use in the patient with kyphoscoliosis.