Parenteral nutritional support solutions can be designed to deliver adequate nutrients to most patients. The basic parenteral solution is composed of dextrose, amino acids, and water. Electrolytes, minerals, trace elements, vitamins, and medications can also be added. Most commercial solutions contain the monohydrate form of dextrose that provides 3.4 kcal/g. Crystalline amino acids are available in a variety of concentrations, so that a broad range of solutions can be made up that will contain specific amounts of dextrose and amino acids as required.
Typical solutions for central vein nutritional support contain 25–35% dextrose and 2.75–6% amino acids depending upon the patient's estimated nutrient and water requirements. These solutions typically have osmolalities in excess of 1800 mOsm/L and require infusion into a central vein. A typical formula for patients without organ failure is shown in Table 29–4.
Table 29–4.Typical parenteral nutrition solution (for stable patients without organ failure). ||Download (.pdf) Table 29–4. Typical parenteral nutrition solution (for stable patients without organ failure).
|Dextrose (3.4 kcal/g) ||25% |
|Amino acids (4 kcal/g) ||6% |
|Na+ ||50 mEq/L |
|K+ ||40 mEq/L |
|Ca2+ ||5 mEq/L |
|Mg2+ ||8 mEq/L |
|Cl– ||60 mEq/L |
|P ||12 mEq/L |
|Acetate ||Balance |
|MVI-12 (vitamins) ||10 mL/day |
|MTE (trace elements) ||5 mL/day |
|Fat emulsion 20% ||250 mL five times a week |
|Typical rate ||Day 1: 30 mL/h |
| ||Day 2: 60 mL/h |
|By day 2, solution provides: ||Calories: 1925 kcal total |
| ||Protein: 86 g |
| ||Fat: 19% of total kcal |
| ||Fluid: 1690 mL |
Solutions with lower osmolalities can also be designed for infusion into peripheral veins. Typical solutions for peripheral infusion contain 5–10% dextrose and 2.75–4.25% amino acids. These solutions have osmolalities between 800 and 1200 mOsm/L and result in a high incidence of thrombophlebitis and line infiltration. These solutions will provide adequate protein for most patients but inadequate energy. Additional energy must be provided in the form of emulsified soybean or safflower oil. Such intravenous fat solutions are currently available in 10% and 25% solutions providing 1.1 and 2.2 kcal/mL, respectively. Intravenous fat solutions are isosmotic and well tolerated by peripheral veins.
Typical patients are given 200–500 mL of a 20% solution each day. As much as 60% of total calories can be administered in this manner.
Intravenous fat can also be provided to patients receiving central vein nutritional support. In this instance, dextrose concentrations should be decreased to provide a fixed concentration of energy. Intravenous fat is associated with less glucose intolerance, less production of carbon dioxide, and less fatty infiltration of the liver and has been increasingly utilized in patients with hyperglycemia, respiratory failure, and liver disease. Intravenous fat has also been increasingly used in patients with large estimated energy requirements. The maximum glucose utilization rate is approximately 5–7 mg/min/kg. Patients who require additional calories can be given them as fat to prevent excess administration of dextrose. Intravenous fat can also be used to prevent essential fatty acid deficiency. The optimal ratio of carbohydrate and fat in parenteral nutritional support has not been determined.
Infusion of parenteral solutions should be started slowly to prevent hyperglycemia and other metabolic complications. Typical solutions are given initially at a rate of 50 mL/h and advanced by about the same amount every 24 hours until the desired final rate is reached.
et al. The impact of home parenteral nutrition on the burden of disease including morbidity, mortality and rate of hospitalisations. Clin Nutr ESPEN. 2018 Dec;28:222–7.
et al. Overview of home parenteral nutrition: an update. Nutr Clin Pract. 2017 Dec;32(6):739–52.
et al. American Society for Parenteral and Enteral Nutrition guidelines for the selection and care of central venous access devices for adult home parenteral nutrition administration. JPEN J Parenter Enteral Nutr. 2019 Jan;43(1):15–31.
et al. Supplemental parenteral nutrition: review of the literature and current nutrition guidelines. Nutr Clin Pract. 2018 Jun;33(3):359–69.