Exocrine pancreatic insufficiency (EPI) is the inability to properly digest food due to a lack of digestive enzymes made by the pancreas.EPI is found in humans afflicted with cystic fibrosis and Shwachman-Diamond Syndrome, and is common in dogs.xocrine pancreatic insufficiency (EPI) is the inability to properly digest food due to a lack of digestive enzymes made by the pancreas.