Indications TPN may be the only feasible option for patients who do not have a functioning GI tract or who have disorders requiring complete bowel rest, such as the following: Some stages of ulcerative colitis Bowel obstruction Certain pediatric GI disorders (eg, congenital GI anomalies, prolonged diarrhea regardless of its cause) Short bowel syndrome due to surgery Nutritional content TPN requires water (30 to 40 mL / kg / day), energy (30 to 35 kcal / kg / day, depending on energy expenditure; up to 45 kcal / kg / day for critically ill patients), amino acids (1.0 to 2.0 g / kg / day, depending on the degree of catabolism), essential fatty acids, vitamins, and minerals (see table Basic Adult Daily Requirements for Total Parenteral Nutrition).