Intraperitoneal malpositioning of an extracorporeal membrane oxygenation cannula: a case report

Venovenous extracorporeal membrane oxygenation is an advanced life support modality used in cases of severe respiratory failure when conventional ventilation is no longer effective. While ultrasound and echocardiographic guidance have improved the safety of cannulation, malposition of extracorporeal membrane oxygenation cannulas remains a rare but potentially life-threatening complication. This case presents an unusual instance of intraperitoneal cannula misplacement during venovenous extracorporeal membrane oxygenation initiation, despite the use of standard imaging guidance techniques.

A 39-year-old Italian woman with no significant prior medical history developed Staphylococcus aureus pneumonia that rapidly progressed to acute respiratory distress syndrome. She was intubated and managed with lung-protective mechanical ventilation and prone positioning. Despite these interventions, she developed refractory hypoxemia and hypercapnia, with a PaO₂/FiO₂ ratio dropping to 30 on 100% FiO₂. Venovenous extracorporeal membrane oxygenation support was initiated. Vascular access was obtained under surface ultrasound and transesophageal echocardiographic guidance. A 19-French return cannula was successfully inserted into the right internal jugular vein. A 25-French drainage cannula was introduced into the left femoral vein without resistance. However, instead of blood, a yellow translucent fluid returned from the femoral cannula, raising suspicion of malposition. The cannula was clamped and left in situ while an alternative cannula was inserted in the right femoral vein to commence extracorporeal membrane oxygenation support. Urgent contrast-enhanced computed tomography (CT) revealed that, although the guidewire had initially tracked correctly, a kink in its path led to the cannula entering the peritoneal cavity, forming a loop within the Douglas pouch. The misplaced cannula was safely removed without complications. The patient remained on extracorporeal membrane oxygenation for 11 days and required an additional 6 days of mechanical ventilation before successful extubation. She was eventually discharged without further issues.

This case underscores that, even with appropriate imaging guidance, extracorporeal membrane oxygenation cannula malposition can still occur. A high index of suspicion, careful interpretation of procedural cues, and prompt diagnostic imaging are essential to prevent serious complications. Early recognition and intervention not only preserve the safety and efficacy of extracorporeal membrane oxygenation therapy but also can lead to favorable patient outcomes.