Fatal pneumoperitoneum caused by nasopharyngeal oxygen delivery after transoesophageal echocardiography for cardiac surgery.

We report a case of fatal post-operative pneumoperitoneum in a patient who had undergone urgent mitral valve surgery. In the absence of a proven cause of the pneumoperitoneum (refusal by the family of an autopsy), we can only propose a hypothesis for its origin. The most probable one is that forceful or sustained retrograde flexion of the transoesophageal echocardiographic probe created a lower oesophagus or gastric rupture and that oxygen flow administered by the nasal cannula went straight to the abdominal cavity, leading to tension pneumoperitoneum.