NMS. Surgery

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Chapter 1 ♦ Principles of Surgical Physiology

3. Fats: Administered either continuously or intermittently as lipid emulsion and are necessary to avoid essential fatty acid deficiency. a. Provide the most calories in the smallest volume which may be important in patients with volume restriction; produce less CO 2 . b. Can lead to hypertriglyceridemia; levels should be routinely monitored. 4. Electrolytes: Include the monovalent cations, sodium and potassium; the divalent cations, calcium and magnesium; and the anions, chloride and acetate (converted to bicarbonate in the liver), which can be adjusted as needed. 5. Vitamins and Trace Elements: Provide to avoid acquired deficiencies; specifically, the exogenous administration of B vitamins, vitamin E/ selenium (lipid peroxidation and free radical scavenging), zinc (wound healing, immunity), and chromium (insulin sensitivity) should be considered in patients receiving TPN. 6. Medications: May be incorporated into TPN; e.g., ulcer prophylaxis and insulin. B. Administration route: Usually via a percutaneously placed venous line with the tip located in the vena cava. C. Administration rate: TPN is typically provided continuously. 1. Patients are started at half goal rate for 12 hours to avoid severe hyperglycemia. 2. Decreasing the TPN rate by half prior to stopping may help avoid hypoglycemia. 3. Cycling to allow patients to be disconnected during the day can be accomplished but should only be prescribed on selected patients. D. Complications 1. Include those related to line placement (hemothorax, pneumothorax); infections (line sepsis, pneumonia, acalculous cholecystitis); hyperglycemia (associated with increased infection risk and death); hepatic dysfunction; and abnormalities in electrolytes, vitamins, fatty acids, and trace elements. 2. TPN is associated with higher morbidity and mortality than enteral nutrition.

TRUSTED SOURCE American Society for Parenteral and Enteral Nutrition: Parenteral Nutrition Resources. Available at https://www.nutritioncare.org/PNResources/

CUT TO CASEBOOK See NMS Surgery Casebook , 3rd edition, Case 12.24: Total Parenteral Nutrition.