A 975-g birth weight, white male infant was delivered by spontaneous vaginal delivery to a 17-year-old mother at 26 weeks' gestation. Upon delivery, the infant presented with cyanosis, good heart rate, and poor respiratory effort. The infant was then intubated and stabilized. Apgar scores of 5 and 6 were assigned at 1 and 5 minutes, respectively. During the first 72 hours of life, the infant received four doses of surfactant for respiratory distress syndrome. On day 3, an echocardiogram revealed a patent ductus arteriosus for which he received four doses of indomethacin. During this time the infant received lowdose pressor support for mild hypotension. The initial cranial ultrasound on day 9 revealed a small germinal matrix hemorrhage with a questionable parenchymal cyst. The infant was initiated on feeds by day 8 and advanced to full feeds over 3 days. On day 10, the infant was found to have necrotizing enterocolitis for which he received surgically placed bilateral abdominal drains without an open laparotomy procedure. A blood culture drawn on day 10 was subsequently positive for Escherichia coli. During the next 24 hours the infant's condition began to deteriorate prompting an exploratory laparotomy, which revealed a perforation in the proximal jejunum adjacent to the ligament of Treitz. The position of the perforation prevented ostomy placement; therefore, a primary closure was performed. Perioperatively, the infant presented with severe hypotension for which he received multiple pressor drips and fluid boluses. Ventilator settings were greatly increased to compensate for worsening respiratory status. Although the infant was being treated with vancomycin, gentamicin, and metronidazole, his white blood count decreased to 1670/mm. Postoperatively, the infant was placed on a fentanyl infusion for pain control. On day 12, the infant weighed 1334 g, 359 g above birth weight. The infant's umbilical venous line began leaking on day 13, necessitating the surgical placement of a silicon 2.7 Fr. Broviac catheter into the right saphenous vein through a subcutaneous tunnel. The catheter was advanced into the right iliac vein and was sutured at the cuff. Aspiration on the catheter revealed good blood return and placement was reported to be in the inferior vena cava, at the level of the fourth-lumbar vertebrae, by abdominal anteroposterior radiograph.Blood return through the catheter became sluggish and could not be obtained on the second day after placement, day of life 15. At this time the infant was on minimal ventilator settings but continued pressor support. The infant exhibited anasarca at a weight of 1678 g, 703 g above his birth weight. Currently the infant was receiving total parenteral nutrition (TPN) consisting of 9% dextrose hyperalimentation with 3 g/kg/d of intralipid through the central line. All other antibiotics and inotropic drugs were infused through the peripheral site. On day 15 and 16, the infant's serum sodium ranged between 140 and 149 mEq/l and potassium between 2.6 and 3.4 mEq/l. His serum glucos...