Pneumoperitoneum in the newborn infant.

Fifty-three newborns with pneumoperitoneum were treated between July 1980 and July 1985. The birth weights of these infants ranged from 600 to 4350 grams; nearly 75 per cent weighed less than 1500 grams. The etiology of the pneumoperitoneum and the hospital survival were reviewed. All operative patients had exploratory surgery through an upper abdominal transverse incision extending across both rectus muscles. All gastric and duodenal perforations were closed primarily; the perforations in the remaining gastrointestinal tract were generally exteriorized through the lateral edge of the wound. The single leading cause of pneumoperitoneum in the newborn is necrotizing enterocolitis, accounting for 60 per cent of the patients in this series; 78 per cent of these infants survived. All infants with ("spontaneous") ileal perforations survived. The two patients with colon perforations (from meconium plug obstruction) died, one of congenital heart disease associated with Down's syndrome and the other of hyaline membrane disease. One patient who had mild hyaline membrane disease, who was not ventilated, and who did not have mediastinal emphysema also had pneumoperitoneum for which no cause was found at laparotomy ("spontaneous"). He survived. In six critically ill infants (11% of the series) pneumoperitoneum developed secondary to mediastinal dissection of air from ventilators. None of these infants was operated on because an intestinal perforation as a source of the pneumoperitoneum could reliably be excluded by the presence of pneumomediastinum and/or a negative paracentesis. This group of infants warrants special attention, because in them "negative" laparotomies performed in search of an intestinal perforation would certainly compromise their already precarious conditions.