Surgery MCQ Answer 101

Answer: b, d



The degree of hypermetabolism is generally related to the severity of injury. Patients with long-bone fractures have a 15–25% increase in metabolic rate, whereas metabolic rates in patients with multiple injuries increases by 50%. These metabolic rates in trauma patients are contrasted with those in postoperative patients, who rarely increase their BMR by more than 10–15% following operation. Studies have shown that uninjured volunteers are able to dispose of exogenous glucose load much more readily than injured patients. Other studies have demonstrated a failure to suppress hepatic glucose production in trauma patients during glucose loading or insulin infusion. Thus, profound insulin resistance occurs in injured patients. Skeletal muscle is the major source of nitrogen that is lost in the urine following extensive injury. Although it is recognized that amino acids are released by muscle in increased quantities following injuries, it has only been recently appreciated that the composition of amino acid reflux does not reflect the composition of muscle protein. The release is skewed towards glutamine and alanine, each of which comprise about one-third of the total amino acids released by skeletal muscle. To support hypermetabolism, stored triglyceride is mobilized at an accelerated rate. Although mobilization and use of free fatty acids are accelerated in injured subjects, if unfed, severely injured patients rapidly deplete their fat and protein stores.

Category: Surgery MCQs