Paradoxical carbon dioxide embolism during laparoscopic unroofing of a recurrent nonparasitic liver cyst.

C arbon dioxide (CO2) embolism is a rare but severe complication of laparoscopic surgery. It has been reported during laparoscopic cholecystectomy and hepatic resections. In open hepatic surgery, patients with intrapulmonary or intracardiac arteriovenous communications (i.e., patent foramen ovale [PFO]) are at risk for paradoxical air embolism, as air can pass into the systemic circulation. We report the rare case of a patient with a paradoxical CO2 embolism (PCO2E) with elevated end-tidal CO2 concentrations due to an undiagnosed PFO occurring during the laparoscopic unroofing of a congenital liver cyst.