A 56 year old female patient was transferred to the operating room for the repair of anterior cruciate ligament under general anesthesia. Initial vital sign was stable, but there was gradual decreases of the blood pressure and end-tidal CO₂ after femur tourniquet application. We suspected the pulmonary thromboembolism, and started massive treatment of using ventilator with 100% O₂, various invasive monitors and many vasopressors. Because the patient's vital sign was so unstable, we finally made a decision of using emergency bypass system (Capiox EBS®, Terumo, Japan) by femoral artery and vein. After that, we transferred the patient to intensive care unit, and continued vigorous treatment. The patient was diagnosed as pulmonary thromboembolism by CT scan. We treated her with infusion of heparin and maintained ACT above 200 second. The 4th day at the intensive care unit, we removed the emergency bypass system. We transferred her to general ward without any complication after 12th day postoperatively.