Which of the following is NOT among the elements excreted at higher rates in urine during the flow phase after burn injury?

• A. Nitrogen
• B. Magnesium
• C. Calcium
• D. Potassium

Answer: (C)

The flow phase after a burn is a highly catabolic state where the body rapidly breaks down protein and loses electrolytes in the urine. Nitrogen appears in higher amounts in urine because of increased proteolysis and nitrogen disposal from amino acids. Potassium and magnesium are also lost in greater quantities in this phase due to cellular injury, hormonal shifts, and renal wasting. Calcium, however, does not show a consistent rise in urinary excretion during the flow phase; calcium balance is more influenced by bone turnover and other factors rather than a straightforward increase in urinary loss in this stage. So, calcium is not among the elements excreted at higher rates in urine during the flow phase after burn injury.