Intraoperative Pulmonary Thromboembolism due to Unknown Causes

A 55-year-old woman with a history of uneventful laparoscopic chorecystectomy was scheduled to undergo right hemithyroidectomy for thyroid tumor under general anesthesia. Her thyroid function was normal. About 20 minutes after skin incision, intratracheal pressure suddenly increased from 15 to 40 cmH2O, blood pressure and heart rate decreased, and cardiac arrest occurred. Cardio-pulmonary resuscitation was immediately and successfully performed and hemodynamics returned to normal, but the operation was postponed. Pulmonary embolism was suspected and heparine and urokinase were administered, although the patient did not have suspected risk factor for thromboembolism. The patient's condition improved gradually. The diagnosis was established by pulmonary scintigram on the 16th day after the cardiac arrest. When sudden changes in respiratory and circulatory states are observed during anesthesia, pulmonary embolism should be considered as a possible cause, even if the patient does not have risk factor for embolism.