Which of the following should a nursing assistant observe for in a resident's vomit?

A nursing assistant should be particularly attentive to vomit that is red, contains blood, or resembles wet coffee grounds because these signs can indicate serious underlying medical conditions. The presence of blood in vomit (known as hematemesis) could suggest gastrointestinal bleeding, which requires immediate medical intervention. Vomit that looks like wet coffee grounds typically indicates that blood has been in the stomach for some time, where the stomach acids have altered its appearance. This can signify a bleeding ulcer or other severe condition that necessitates urgent care.

In contrast, while yellow or green vomit may suggest bile and could be assessed, it is less immediately alarming than the presence of blood. A pleasant odor in vomit is not typically a concern in the context of medical observation, and clear, watery vomit may not signal an urgent situation, especially if it is due to simple nausea without blood. Thus, the key focus should be on any signs of blood or altered blood in the vomit, as this can be indicative of a critical health issue that warrants prompt medical attention.