Hypercarbia is a potential complication during laparoscopic surgery. However, is more likely to occur in extraperitoneal surgery than in intraperitoneal surgery because insufflated CO2 gas can diffuse easily into the surrounding tissues. We report the anesthetic course and complications encountered during endoscopic harvesting of a saphenous vein with CO2 insufflation in coronary artery bypass surgery. Although the surgery was successful, the patient developed signs and symptom of CO2 absorption: tachycardia, hypertension, hypercarbia and acidosis. Possible mechanisms are presented, along with a discussion of the prompt diagnosis and treatment. For the management of laparoscopic extraperitoneal surgery, care must be taken to monitor the CO2 insufflation pressure, perform a routine examination and palpation of the chest wall, use of N2O with caution, increase the level of ventilation to eliminate CO2, and excluding other causes of subcutaneous emphysema and hypercarbia.