What defines a contraindication for enteral nutrition?

A complete obstruction of the small bowel indeed defines a contraindication for enteral nutrition. This situation arises because enteral nutrition involves the delivery of nutrients directly into the gastrointestinal tract. If there is a complete obstruction, food and nutrients cannot pass through the digestive system, making the use of enteral nutrition not only ineffective but potentially dangerous. If nutrition is introduced in the presence of an obstruction, it could lead to complications such as aspiration, infection, or increased bowel distension, which can worsen the patient's condition.

In contrast, the other options are not contraindications. Mild hypertension may require monitoring and possible lifestyle or dietary changes, but it does not prevent a person from receiving enteral nutrition. Similarly, a need for weight gain typically indicates that enteral nutrition might be beneficial, as it can help provide adequate caloric intake. A stable chronic illness does not usually contraindicate enteral nutrition; rather, it can often be managed effectively with appropriate nutritional support.