Which substance is often combined with 5% dextrose in water for total parenteral nutrition?

In total parenteral nutrition (TPN), the goal is to provide essential nutrients directly into the bloodstream, bypassing the digestive system. The combination of 5% dextrose in water serves primarily as a source of carbohydrates to provide energy. However, to meet the comprehensive nutritional needs of a patient, particularly for those who cannot consume food orally or have absorption issues, it is necessary to include proteins in the form of amino acids.

Amino acids are the building blocks of proteins and are crucial for numerous bodily functions, including muscle repair, immune function, and hormone production. In a TPN solution, amino acids are often mixed with 5% dextrose to ensure that all macronutrients – carbohydrates, proteins, and fats – are supplied to the patient. This mixture helps maintain an adequate nutritional status, supports metabolic functions, and aids in recovery.

While lipid emulsions are also a component of TPN, they are typically given as a separate infusion because they serve as a source of essential fatty acids and additional calories. Therefore, amino acids are the most common substance combined with dextrose in TPN formulations, making this the correct answer.