Total nutrient admixtures (3-in-1): pros vs cons for adults.

Total nutrient admixture (TNA) is a complete parenteral nutrition (PN) formulation composed of all macronutrients, including dextrose, amino acids, and intravenous fat emulsions (IVFE), in one bag. The TNA may be safely administered to the patient, with all components aseptically compounded and minimal administration manipulation required, lending itself to decreases in risks of catheter contamination and patient infections. The TNA is compatible and stable at recommended concentrations, and since the IVFE is in the TNA, it is infused at slower rates, allowing for better fat clearance. The TNA offers convenience of administration and a potential cost savings to the healthcare institution both directly and indirectly. Unfortunately, the TNA is not without concerns. At low macronutrient concentrations (lower than recommended), the formulation is compromised. Greater divalent and monovalent cation amounts and increased concentrations of phosphate and calcium may destabilize the TNA or result in precipitation, respectively. With the addition of IVFE in the TNA, catheter occlusion is greater and larger pore size filters are necessary, resulting in less microbial elimination. Determining if the implementation of the TNA is appropriate for an institution requires a recognition of the advantages and disadvantages of the TNA as well as an understanding of the institution's patient population and their nutrition requirements.