Neonatal pneumopericardium.

The clinical data and radiographs of 50 neonates with pneumopericardium (PPC) were reviewed. Most of these neonates were premature, low-birth-weight infants with hyaline membrane disease who required ventilatory assistance. The presence of other extraventilatory air prior to (or concurrent with) PPC, the use of cardiopulmonary resuscitation with intracardiac drug administration, and improper endotracheal tube placement were contributory factors. However, it was not possible to determine why some infants progressed to PPC and others, with similar disease and predisposing conditions, did not. The primary radiographic sign of PPC is the "halo" sign, which was apparent in 96% of these cases. When this sign was not present, other signs, such as the "pericardial line" sign, were helpful. The overall mortality was 72%. Thirty-three per cent of the fatalities were related to PPC; however, the long-term prognosis is probably more closely related to the severity of underlying lung disease or other complications than to PPC.