Stimulation at acupoints could be of beneficial effects during the perioperative period. In this study the investigators tend to verify the effect of dual acupoints stimulation on pulmonary complications after abdominal surgery in aged patients.

Postoperative pulmonary complications contributes to the high morbidity of aged patients. The incidence could be as high as 30~50% in those undergoing abdominal surgery. Stimulation at acupoints have been to alleviate inflammatory response,improve pain management and decrease consumption of opioids, indicating a beneficial effect on pulmonary complications. In this study the investigators tend to verify the effect of dual acupoints stimulation on pulmonary complications after abdominal surgery in aged patients.

Inclusion Criteria:

• Informed consented
• Scheduled for elective abdominal surgery under general anesthesia
• Age >=65 yrs

Exclusion Criteria:

• Patients with contraindications to transcutaneous electrical stimulation
• Patients with difficulty in communication that may confuse follow-up
• emergent surgeries
• Patients with pneumonia or needed ventilation before surgery
• Patients with history of pulmonary surgery
• Scheduled surgery involves thoracic manipulations
• Patients who attended clinical studies in the last 3 months