input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A chronic opioid abuser undergoes emergency surgery. Following the operation, the man is started on a patient controlled analgesia (PCA) thought to be dosed adequately to control his pain in the face of his opioid tolerance. He reports intense pain 6 hours after the conclusion of the surgery. Which agent could have been given intraoperatively to reduce this patient's risk of developing postoperative hyperalgesia?   (A) Ketamine   (B) Midazolam   (C) Propofol   (D) Etomidate
output: ['(A) Ketamine <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Ketamine  (B) Midazolam  (C) Propofol  (D) Etomidate <> possible answers', "  A chronic opioid abuser undergoes emergency surgery. Following the operation, the man is started on a patient controlled analgesia (PCA) thought to be dosed adequately to control his pain in the face of his opioid tolerance. He reports intense pain 6 hours after the conclusion of the surgery. Which agent could have been given intraoperatively to reduce this patient's risk of developing postoperative hyperalgesia? <> context"]