Total parenteral nutrition: clinical considerations

Nutritional support is recognized as an important therapeutic intervention to promote wound healing sustained traumatically, surgically, or caused by chronically debilitating illness, and as an adjunctive therapy in patients with life-threatening infectious diseases. The total parenteral nutrition (TPN) formulation should be carefully tailored to meet the needs of each individual patient. Factors important in determining the TPN formula include nutritional assessment; total volume; duration of therapy; solution compatibilities; and disease-specific clinical considerations. TPN should be employed for patients who are unable to or should not consume nutrients via the gastrointestinal tract and patients who cannot consume enough nutrients to sustain nutritional requirements. Patients need not be malnourished to qualify for TPN. The provision of nutritional support requires calculation of basic components of the normal diet, including water, carbohydrate, fat, protein, electrolytes, vitamins, and trace elements. The total daily expenditure of calories can be calculated as a multiple of the patient's basal energy expenditure. Disease-specific considerations may require alterations in the amount of protein provided and the percentage of dextrose and fat calories utilized.