Figure 1. Radiograph of the abdomen showing free air around the liver.
Figure 2. Contrast media in the retroperitoneal space inserted via draining catheters.
Free intra-abdominal air on radiography is an ominous sign, usually indicating perforation of a viscus. In the premature neonate, the cause is usually necrotizing enterocolitis.1,2 The term "free air" usually refers to air within the peritoneal cavity, but in this case, the air was in the retroperitoneal space along with extravasated parenteral nutrition fluid. Apparently, the UVC eroded the wall of the inferior vena cava, resulting in extravasation of total parenteral nutrition (TPN) fluid. The origin of free air was either direct catheter air embolus or represented accumulation of microbubbles from the TPN fluid. Biochemical analysis of the fluid aspirated confirmed it as lipid-containing TPN fluid.
A total of 700 mL of crystalloid and TPN was infused through the UVC during the 5-day period from its insertion to its removal. If the vena caval perforation occurred at the time of insertion of the UVC, a larger volume of fluid would have been expected on paracentesis. Therefore, there was likely gradual erosion of the vena cava wall after insertion of the UVC.
Complications previously recognized with UVC insertion include thrombosis, embolism, vasospasm, vessel perforation, hemorrhage, infection intestinal, and renal and limb damage.3 Small air emboli have been described following insertion of peripheral or central venous catheters.4,5 This report highlights an unusual hazard of umbilical vessel catheterization and a radiological sign: vena cava erosion and perforation with accumulation of retroperitoneal gas. To our knowledge, this cause of radiological diagnosed free intra-abdominal air in a neonate has not previously been described.
Accepted for publication May 10, 2000.
Reprints: C. Anthony Ryan, MD, MRCPCH, Neonatal Intensive Care Unit, Erinville Hospital, Western Road, Cork, Ireland (e-mail: firstname.lastname@example.org).
Radiological Case of the Month. Arch Pediatr Adolesc Med. 2001;155(4):524. doi:10.1001/archpedi.155.4.523