What is the primary purpose of parenteral nutrition?

The primary purpose of parenteral nutrition is to provide calories and restore nitrogen balance. This form of nutrition is administered intravenously and serves individuals who are unable to obtain adequate nutrition through oral or enteral routes due to various medical conditions, such as gastrointestinal disorders, surgical recovery, or malabsorption issues.

In parenteral nutrition, a carefully formulated mixture of carbohydrates, proteins (in the form of amino acids), and fats is delivered directly into the bloodstream to ensure that the patient's nutritional needs are met. This is crucial not just for energy, but also for maintaining an appropriate nitrogen balance, which is important for tissue repair and growth, especially in clinical settings where patients may be in a catabolic state due to illness or injury.

Other options are not aligned with the primary purposes of parenteral nutrition. For instance, replacing physical therapy does not address nutritional needs directly and is more focused on rehabilitation. Administering medications effectively may be a component of some patients' care, but it is not the primary function of parenteral nutrition. Enhancing patient social interactions is also not related to the nutritional goals of this therapy. Therefore, option B accurately reflects the essential role that parenteral nutrition plays in patient care.