SUMMARY

Perioperative nutritional support is indicated for malnourished patients, severely catabolic patients (e.g., trauma, burns, sepsis), cancer patients, and patients with organ failure. Special nutritional support is not indicated for well-nourished surgical patients with uncomplicated surgery who will have a limited period of fasting (i.e., 2 to 4 days). If nutritional support is indicated, it should be initiated as soon as possible. Many patients tolerate enteral nutritional support through gastric or jejunal feeding tubes. In the absence of contraindications for enteral feeding, it should be attempted with a willingness to rapidly switch to parenteral nutrition if the enteral route fails. Central venous administration of nutrition should be reserved for patients with a nonfunctioning gastrointestinal tract because of the complications of central venous catheterization. Septic patients with gastrointestinal tract dysfunction may have reduced intestinal complications with duodenal or jejunal administration of 5 to 10 mL/hour of glutamine-containing amino acid solutions.

The optimal nutritional prescription includes adequate protein intake (as amino acid solutions) in aiming to keep the patient in nitrogen equilibrium as well as calories in the form of glucose and fat to provide essential fatty acids at a rate equal to or slightly less than measured daily energy expenditure. Protein and energy requirements should be considered separately and monitored individually: nitrogen balance for protein, indirect calorimetry for energy. A convenient starting point for protein administration is 1.5 to 2.0 g/kg/day, with glucose adjusted to provide calculated or measured nonprotein calories per day. In the absence of indirect calorimetry, 25 kcal/kg/day is a useful starting point. The prescription must also include vitamins, minerals, and trace elements. Markers of muscle protein metabolism, such as serum 3-methylhistidine, transferrin, and prealbumin, are monitored to rule out extensive catabolic activity. Water balance is followed by daily weighing, and serum electrolyte levels, liver enzyme levels, and renal function test results are also monitored frequently. Properly administered, perioperative nutritional support can markedly enhance the care of selected surgical patients.