Nonocclusive mesenteric ischemia: A rare but lethal complication of enteral nutrition in critically ill patients.

Background: The American Society for Parenteral and Enteral Nutrition (ASPEN)/ Society of Critical Care Medicine and the European Society for Clinical Nutrition and Metabolism guidelines recognize that critically ill patients receiving stable, low doses of vasopressors have experienced the advantages of early initiation of enteral nutrition (EN). However, clinical questions remained unanswered including vasopressor combinations associated with complications, the advent of other therapies during hypotensive states, as well as the volume and content of EN that might contribute to the development of a nonocclusive mesenteric ischemia (NOMI).

Presentation: A 68-year old male with a history of hypertension, hyperlipidemia, atrial fibrillation, coronary artery disease with two-vessel bypass grafting, and peripheral vascular disease underwent subtotal excision of an infected right axillofemoral-femoral bypass graft. Postoperatively, EN was held because of hemodynamic instability and postsurgical complications. A fiber-free, high-protein, and low-residue formula was started at 10 ml/h while the patient was receiving stable doses of midodrine, norepinephrine, and vasopressin. Despite advancement of tube-feed rates to goal, nasogastric output never exceeded 300 ml. Computerized tomography of the abdomen showed diffuse bowel distention with pneumatosis, concerning for bowel ischemia. No surgical interventions were pursued, and the patient died.

Conclusions: Our patient developed NOMI postoperatively while receiving EN. Further studies addressing EN route, trophic vs full EN, recommended formula, the safety of vasoactive agents, the addition of fiber to EN, and continuous venovenous hemodiafiltration in relation to NOMI are needed, as there continues to be clinical controversy regarding these topics.