Prediction of mortality in newborn infants with severe congenital diaphragmatic hernia using the chest radiographic thoracic area

Abstract

Aims: To evaluate whether the pre-operative chest radiographic thoracic area (CRTA) in newborn infants with congenital diaphragmatic hernia (CDH) was related to the length of mechanical ventilation and the total length of stay and whether CRTA predicted survival to discharge from neonatal care. Methods: Retrospective observational cohort study at King’s College Hospital, London, UK. The CRTA was assessed by free-hand tracing of the perimeter of the thoracic area as outlined by the diaphragm and the rib cage and excluded the mediastinal structures and abdominal contents in the thorax (figure 1) and calculated using the Sectra PACS software in newborn infants admitted with CDH at KCH in a 10 year period (2007-2017). Results: 84 infants with CDH (70 left-sided) were included with a median (IQR) gestation of 36 (34 - 39) weeks. Fifty-four (64%) survived to discharge from neonatal care. In the infants who survived the CRTA was not related to the length of mechanical ventilation (r= 0.136, p=0.328) or the total duration of stay (r=0.095, p=0.495). The median (IQR) CRTA was higher in infants who survived [1780 (1446 – 2148) mm2] compared to in the deceased infants [1000 (663 – 1449) mm2] after correcting for confounders (adjusted p=0.01). Using receiver operator characteristics analysis, the CRTA predicted survival to discharge from neonatal care with an area under the curve of 0.826. A CRTA higher than 1299 mm2 predicted survival to discharge with 85 % sensitivity and 73 % specificity. Conclusions: The chest radiograph in infants with severe CDH can predict survival from neonatal care with high sensitivity and moderate specificity.