When Air Is Not an Emergency: Using Intraperitoneal Sevoflurane to Rule Out Perforation.

Idiopathic pneumoperitoneum (IP) is a rare diagnosis of exclusion typically discovered during imaging for unrelated concerns. Most pneumoperitoneum cases are secondary to visceral perforation, necessitating urgent surgical intervention. However, IP is a distinct, non-surgical condition that can present asymptomatically, complicating clinical decision-making. A 76-year-old female with multiple comorbidities presented to the emergency department after her Holter monitor detected intermittent, third-degree heart block. She was asymptomatic from a gastrointestinal standpoint, with a benign abdominal exam and normal inflammatory markers. However, chest imaging incidentally revealed pneumomediastinum and pneumoperitoneum, raising concern for gastrointestinal perforation. A diagnostic laparotomy was performed after temporary transvenous pacing was established. No visceral perforation was identified. Interestingly, sevoflurane administered through an endotracheal tube was detected in the abdominal cavity, suggesting a thoracoabdominal communication, possibly from a ruptured mediastinal bleb. She remained hemodynamically stable throughout hospitalization, had a permanent pacemaker placed, and was discharged in stable condition. This case highlights an unusual presentation of asymptomatic idiopathic pneumoperitoneum with suspected thoracoabdominal gas tracking, confirmed by intraoperative detection of sevoflurane. It underscores the importance of cautious interpretation of incidental pneumoperitoneum findings and the need to consider conservative management in the absence of peritonitis.