Current Concepts in Parenteral Nutrition

Abstract

Surgical stress causes specific physiologic and biochemical alterations. Hypothalamic-pituitary stimulation leads to increased production of antidiuretic hormone, thyrotropin and adrenocorticotropin, affecting water balance, catabolism, renal reabsorption of sodium, and excretion of potassium. Gastrointestinal fluid loss in 24 hours may be more than twice the plasma volume. In addition to water, calories must be provided to meet the energy requirements of body metabolism and prevent excessive catabolism. Potassium loss must be replaced when parenteral feedings are the sole source of nutrition. An intravenous fat emulsion is available which provides a high caloric intake in a relatively small amount of fluid.