How does the location of a fistula in the GI tract affect its output and metabolic risk?

• A. Higher fistula location leads to lower output
• B. Lower fistula location leads to higher output
• C. The higher the fistula location, the greater the output and the risk of metabolic derangements
• D. Location does not affect output

Answer: (C)

Proximal fistulas tend to produce higher volumes of drainage because they bypass much of the absorptive length of the small intestine. The GI tract secretions from the stomach, pancreas, bile, and intestinal mucosa are substantial; when a fistula is located high, those secretions are lost through the fistula instead of being reabsorbed, leading to large fluid and electrolyte losses. This drives dehydration and metabolic disturbances, such as electrolyte imbalances and acid-base shifts. If the fistula is located further down the tract, there is more opportunity for absorption before reaching the fistula, so daily output is usually lower and metabolic risk is reduced. Thus, the higher the fistula location, the greater the output and the risk of metabolic derangements.