Supplementary Material for: Gas Embolism Caused by Portal Vein Gas: Case Report and Literature Review

<i>Introduction:</i> We describe a case of pulmonary gas embolism caused by portal vein gas (PVG) observed using echocardiography. Echography revealed gas flowing through the hepatic vein, inferior vena cava, right atrium, and right ventricle, as well as pulmonary hypertension. The patient was diagnosed as having pulmonary gas embolism caused by PVG. <i>Objective:</i> We consider PVG routes to pulmonary circulation, diagnosis of gas embolism caused by PVG, and treatment of gas embolism caused by PVG.<i>Methods:</i> We reviewed reports of eight cases of gas embolism caused by PVG and compared these cases to cases of gas embolism without PVG. <i>Results:</i> Mortality of gas embolism caused by PVG was 67%, positive blood culture was observed in six cases, and pulmonary edema was seen in three cases. PVG initially excites microbubble formation, which causes tissue damage in the liver and liver abscess. A large volume of PVG causes portal obstruction. As a result, portal hypertension, a portosystemic shunt or gastrointestinal congestion can occur. PVG can travel to the systemic vein through the liver or portosystemic shunt without anomaly and cause pulmonary gas embolism, followed by arterial embolism. In this environment, sepsis easily occurs. Echocardiography is useful for diagnosis of gas embolism caused by PVG, but the gas can be seen intermittently. The view of pulmonary edema is important for pulmonary gas embolism caused by PVG. <i>Conclusion:</i> It is important to treat the underlying disease, but PVG must be considered and treated as the gas embolism’s source.