Effects of Different Types of Anesthesia on Stress Response in Laparoscopic Gastric Bypass for Type 2 Diabetes Mellitus

General anesthesia can be considered as a combination of hypnosis, antinociception and immobility. Explore the effect of three kinds of anesthesia,that is the total intravenous anesthesia, inhalation anesthesia and inhalation and intravenous anesthesia on stress reactions generated by patients with diabetes conducted gastric - bypass surgery , and choose a best way from three kinds of anesthesia to control stress reaction of diabetics. After selecting the appropriate anesthesia method, assess the effect of dexmedetomidine on controlling stress response from diabetics undergoing laparoscopic gastric-bypass surgical.