Safety Study to Evaluate the Occurrence of EFAD in Pediatric Patients With PNAC Who Require More Than Eight Weeks of Omegaven Treatment

This study is monitoring whether children receiving a fish oil-based IV nutrition supplement called Omegaven for more than 8 weeks develop a condition called essential fatty acid deficiency (EFAD). These children have liver disease related to IV nutrition (called PNAC) and cannot tolerate regular feeding. **You may be eligible if...** - Your child is under 18 years old - Your child has been diagnosed with PNAC (liver injury from IV nutrition), shown by elevated liver bilirubin levels - Your child cannot tolerate oral or tube feeding and needs IV nutrition - Your child is expected to need Omegaven treatment for at least 8 weeks **You may NOT be eligible if...** - Your child received Omegaven within the past 4 weeks - Your child has another known cause of chronic liver disease (e.g., hepatitis C, cystic fibrosis, biliary atresia) - Your child has cirrhosis, a blood clot in the portal vein, or has had a liver transplant - Your child has major heart problems, multi-organ failure, or a life-threatening illness like sepsis Talk to your doctor to see if this trial is right for you.