<prompt> A 72-year-old man undergoes resection of an abdominal aneurysm. He arrives in the ICU with a core temperature of 33degC 91.4degF and shivering. Which of the following is a physiologic consequence of the shivering?Rising mixed venous O2 saturationIncreased production of CO2Decreased consumption of O2Rising base excess  <response>: Shivering is the physiologic effo of the body to generate heat to maintain the core temperature. In healthy persons, shivering increases the metabolic rate by 3 to 5 times and results in increased O2 consumption and CO2 production. In critically ill patients, these metabolic consequences are almost always counterproductive and should be prevented with other means employed to correct systemic hypothermia. In the presence of vigorous shivering, O2 debt in the muscles and lactic acidemia develop. 