When are serum glucose levels the highest?

• A. Cooling phase of CPB
• B. Rewarding phase of CPB
• C. Rewarming phase of CPB
• D. Weaning from CPB

Answer: (B)

During rewarming, the body's stress response ramps up and metabolism speeds back up as normothermia returns. This involves a surge of catecholamines and cortisol and a rise in inflammatory mediators, which increases hepatic glucose production (glycogenolysis and gluconeogenesis) and reduces insulin sensitivity. The result is a rapid rise in blood glucose, often reaching its highest levels during this rewarming phase. Cooling lowers metabolic demand, so glucose use stays relatively lower, and weaning from CPB follows after glucose has already peaked during rewarming.