Postoperative Nutritional Support in Pediatric Patients
Endogenous carbohydrate stores are limited, and, while muscle amino acids are available for gluconeogenesis in the stressed state, protein should not be considered a viable energy source under any clinical condition. Thus, fat is the only macronutrient stored in sufficient quantity so as to represent a useful endogenous energy source in the perioperative period. The metabolic response to major surgery is not unlike the response to major trauma. In the fasting postoperative patient, skeletal muscle protein is mobilized to provide protein for acute-phase reactants and wound healing. Energy is supplied mainly by mobilizing fat stores. In this situation, total parenteral nutrition (TPN) supplies needed energy to limit the breakdown of body fat and protein, and this nutritional therapy prevents depletion of skeletal muscle by providing sufficient protein to maintain the circulating amino acid pool and to aid in tissue repair.
Although withholding oral feeding after GI surgery is common, no proven benefit is noted. The dictum is, “If the gut works, use it.” Early refeeding is beneficial, in part, by stimulating enteric digestive enzyme synthesis. Enteral nutrients are also required to maintain intestinal mucosal integrity and local immunity, since the gut derives roughly 50% of its overall nutritional requirements from luminal sources. Postoperative parenteral nutritional support should be considered if the patient has been or is expected to be restricted to a nothing-by-mouth diet for more than 2 days in term neonates and infants or more than 5 days in older children. As stated, the enteral route should be used whenever possible (eg, following esophageal atresia repair via a trans-anastomotic feeding tube or gastrostomy).