Clinical-pharmacological aspects, application and effectiveness of total parenteral nutrition in surgical patients

The term "total parenteral nutrition" (TPN) refers to the maintenance of an adequate nutritional status, normal body weight and positive nitrogen balance solely by intravenous means. It requires solutions providing calories, amino acids and other nutrients in amounts much greater than those indicated for maintenance of normal body weight. Nutrient solutions have been studied, selected and prepared in our Hospital Pharmacological Service utilizing a sterile closed system, which allows large-volume filtering, sterilizing and bottling devices. For maintenance of weight gain in adults, a basic formula is employed, which provides 1,100 Kcal/1 with pure crystalline amino acids mixed with 50% anhydrous dextrose in water in a ratio of 5.8:1 (160 Kcal:1 g nitrogen). Minerals and vitamins are added to the base solution prior to use and may be increased or decreased by simple addition or omission depending on the patient's condition. This paper is based on 192 surgical patients who received TPN and have been followed in strict cooperation between the Hospital Pharmacological Service and the Surgical Department. The patients, ranging from 23 to 79 years of age, with life threatening diseases and unable to maintain adequate nutrition by the oral route, received TPN through a central catheter inserted via subclavian puncture (146 cases) or through a surgically created internal A-V fistula (46 cases). The condition of the patients generally improved within a few days after starting TPN; and weight gain, wound healing, general improvement and a shorter period of hospitalization were observed. TPN could be efficiently combined with oncologic treatment, and a significant improvement of the patients' performance status and decrease of toxic side-effects due to chemotherapeutic agents were observed. TPN has been successfully applied also in patients with fistulas of the alimentary tract obtaining spontaneous closure and in patients with ulcerative colitis, showing its beneficial effect in allowing complete bowel rest for healing. No major complications or deaths could be attributed to TPN or to the route of administration.