Which daily fistula output best defines high-output for PN indication?

• A. 450 mL/day
• B. 500 mL/day
• C. 400 mL/day
• D. 550 mL/day

Answer: (D)

High-output fistulas lose a lot of fluid each day, which drives the need for nutrition support to meet energy and electrolyte needs and to replace losses. The threshold commonly used to define high-output is more than 500 mL per day. So a fistula output of 550 mL/day clearly meets this criterion, while 500 mL/day is at the threshold and may be considered high-output in some settings but isn’t clearly above it. Outputs of 450 or 400 mL/day are below the cutoff. Therefore, 550 mL/day best defines high-output for PN indication.