Covering of the alveoli and the finest branches of the air passages with a deposit of fluid and protein which impairs oxygen absorption and carbon dioxide removal. The abnormality is linked with shortage of surfactant, which normally reduces surface tension in the mucous layer of the lung and makes respiration possible. The condition occurs principally in premature babies of mothers suffering from diabetes mellitus, and in infants delivered by Caesarean section. At birth the child seems to be breathing well, but within minutes or hours respiratory frequency increases, the baby becomes short of breath, gasps, groans and becomes increasingly blue. Without treatment the child can easily die. Diagnosis is confirmed by X-ray and laboratory tests; the baby is kept in an incubator. Treatment is by administration of oxygen, sometimes by a nasal tube, sometimes by artificial ventilation. Because the child is not breathing out carbon dioxide properly, the blood becomes acidic; this is controlled by the infusion of drugs. Treatment usually lasts for a few days until the child has produced enough surfactant himself to permit normal respiration, but treatment is not always successful.