Which agent is commonly associated with emergence reactions during arousal from general anesthesia?

The correct choice is ketamine, which is known for its association with emergence reactions during the recovery phase from general anesthesia. Emergence reactions are characterized by vivid dreams, hallucinations, delusions, and confusion, which can occur as the patient begins to regain consciousness after the anesthetic effects wear off.

Ketamine is a dissociative anesthetic that works mainly as an NMDA receptor antagonist. Its unique mechanism affects sensation and perception, leading to a disconnect between the senses and the environment during both the anesthetic state and recovery. This property contributes to the potential for emergence reactions, particularly if used in higher doses or in individuals who may be sensitive to its effects.

In contrast, agents like diazepam, propofol, and midazolam are generally associated with smoother arousal and a lower incidence of emergence reactions. Diazepam and midazolam are benzodiazepines that provide sedation and anxiolysis without the dissociative effects seen with ketamine. Propofol, known for rapid onset and recovery, also tends to lead to a more straightforward recovery experience, minimizing the risk of complex emergence phenomena.