Pediatric patients with dyspnea were seen in 31.1% out of 1366 admissions in 3 years. 17.2% of them were newborn infants. The most major causes of dyspnea were atelectasis and hyaline membrane disease in newborns, and dyspnea in infants other than newborns was mostly of pulmonary origin. On the other hand, metabolic dyspnea was also seen in the considerable number in children.
This paper reported the cause of respiratory distress syndrome of premature infants mainly on the basis of autopsy study on 149 cases. The characteristic morphological pattern of the lung in premature infants was studied from the view point of adaptation process. The clinical manifestations of hyaline membrane formation, characteristic atelectasis and bronchiolar emphysema were observed in relation to the birth weight and the survival time after birth. Furthermore, experimental studies were carried out on the autopsied cases. Morphological findings on the lung in premature infants were closely associated with cardio-pulmonary adaptation. Experimental studies on animals lead us to find the facts that the alveolar capillaries are filled with blood gradually after birth and the dilatation of the capillaries in the alveolar wall reaches its peak filled with enough blood after 2 or 3 days. These facts have relation to pulmonary hemorrhage which is most frequently seen 3 days after birth, and also have relation to hyaline membrane disease in which blood congestion is usually present. Thus dyspnea seen in newborn infants, especially in premature babies, seems to have close association with damage in cardio-pulmonary adaptation.
Besides above studies, chest X-rays of over 500 newborn infants were examined with the results that respiratory distress syndrome is seen not only in the infants showing abnormal shadows on the film but also in those who have no pathological findings on the chest X-ray. In the latter cases dyspnea is supposed to be of metabolic and/or abnormality of central nervous system.
