Effect of feeding on ventilation and respiratory mechanics in newborn infants.

Measurements of ventilation and respiratory mechanics were made before and after tube feeding in 24 infants. In 12 infants with the respiratory distresssyndrome tidal volume tended to fall after feeding; as the respiratory rate increased after feeding; as the respiratory rate increased after feeding, minute ventilation remained unchanged. Hypoventilation is therefore unlikely to be the cause of hypoxaemia after feeding. Compliance, resistance, and the work of breathing showed no changes after feeding. In 12 healthy infants feeding had no effects on pulmonary function. There was a slight rise in compliance and a tendency for work of breathing to fall after feeding. Respiratory rate, tidal volume, and minute ventilation remained unchanged. There was therefore no evidence of adverse effects of feeding on any of the factors measured. It is suggested that hypoxaemia without hypoventilation after feeding in infants with pre-existing respiratory distress syndrome might be attributable to a reduction in functional residual capacity associated with a greater extent of airways closure than before feeding.