Proximal high-output fistulas are associated with what systemic risk?

• A. Increased risk of metabolic derangements
• B. No significant metabolic risk
• C. Decreased risk of electrolyte loss
• D. Reduced risk of dehydration

Answer: (A)

Proximal high-output fistulas drain large volumes of fluid that carry bicarbonate and electrolytes with them. This rapid loss disrupts systemic balance, causing metabolic derangements such as metabolic acidosis and electrolyte disturbances (for example, electrolyte depletion and acid-base imbalance). Patients can also become dehydrated and hypovolemic due to ongoing losses. So the main systemic risk is the development of metabolic derangements from substantial bicarbonate and electrolyte loss. The idea that there’s no significant metabolic risk or that electrolyte loss and dehydration are reduced does not fit with the physiology of high-output fistulas.