This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intravenous Anesthetic Agents, Subject name: Anaesthesia
Postoperative shivering in the perioperative period is associated with? 
Select and explain. 
A. Increase oxygen consumption, B. Decreased catecholamine release, C. Decreased hea rate and blood pressure, D. All
A: Increase oxygen consumption
Answer: A: Increase oxygen consumption 
Explanation: Postoperative shivering Primary cause of is perioperative hypothermia Postoperative shivering can greatly increase oxygen consumption, catecholamine release, cardiac output, hea rate and blood pressure, and intracerebral and intraocular pressure. Shivering is uncommon in elderly and hypoxic patients Many drugs, notably meperidine, clonidine, and tramadol, can be used to reduce postoperative shivering However, prevention of hypothermia is the most efficient strategy.