Enteroatmospheric Fistula

An enteroatmospheric fistula is an abnormal opening of exposed bowel directly into an open abdominal wound.

Unlike a conventional enterocutaneous fistula, there is no mature soft tissue tract between bowel and skin. The exposed bowel communicates directly with the atmosphere.

This distinction is critical because spontaneous closure is exceptionally uncommon. The surrounding open abdomen is often inflamed, densely adherent and unsuitable for early definitive surgery.

Common settings include prolonged open abdomen management, abdominal sepsis, repeated laparotomy, bowel injury and direct trauma to exposed bowel.

Enteric fluid appears directly from exposed bowel within the abdominal wound.

Output should be measured daily and described as low, moderate or high. High output above 500 mL per day produces major sodium, fluid and nutritional losses.

The wound may develop severe chemical irritation, tissue maceration, infection and difficulty maintaining temporary abdominal closure.

Associated sepsis, abscesses and intestinal failure are common.

Diagnosis is clinical.

Define the bowel segment involved, daily output, whether distal bowel remains accessible for feeding and whether unresolved intra abdominal sepsis persists.

CT abdomen and pelvis with IV contrast: use when deep abscess, ongoing contamination or another intra abdominal complication is suspected.

Monitor renal function, electrolytes, magnesium, phosphate, nutritional markers and fluid balance closely.

The initial objective is control, not closure.

Isolate fistula effluent completely from the surrounding wound using a dedicated pouch, fistula isolation device or compartmentalised wound system.

Negative pressure wound therapy can be used around an isolated fistula to facilitate wound granulation and effluent management, but negative pressure foam must not be applied directly to exposed bowel or directly over the fistula opening. WSES specifically recommends protecting exposed viscera and isolating fistula effluent.

Correct fluid and electrolyte losses according to measured output.

Nutrition must begin early. These patients are markedly catabolic and have additional nitrogen loss through abdominal fluid and fistula output. WSES recommends immediate nutritional optimisation. Where the gastrointestinal tract is functional, enteral feeding should be used, including feeding distal to the fistula when technically possible. Parenteral nutrition is required when high output prevents adequate enteral feeding or distal access is unavailable.

A typical nutritional target in an open abdomen with major enteric losses is approximately 20 to 30 kcal/kg/day of nonprotein energy and 1.5 to 2.5 g/kg/day of protein, adjusted to clinical condition, renal function and measured nitrogen loss.

Treat intra abdominal sepsis with drainage or operative source control when required. Antibiotics should be directed at active infection rather than continued simply because the fistula remains open.

Do not attempt early fistula takedown in a frozen open abdomen unless uncontrolled sepsis or another life threatening surgical indication forces intervention.

Allow granulation and eventual epithelial coverage or skin grafting where appropriate. The fistula can often be converted functionally into a controlled stoma before reconstruction.

Definitive fistula resection and abdominal wall reconstruction should be delayed until systemic recovery, nutritional restoration and complete maturation of the abdominal wound. WSES recommends delaying definitive treatment until the patient and wound have healed, usually at least 6 months in complex cases.