Three hundred aged(age>65y) patients were randomized to Commom group(C group). Qualitative TOF monitoring (TOF group). Qualitative TOF and transcutaneous partial pressure of carbon dioxide monitoring(Unite group). Anesthetic management was standardized in all subjects .The patients of C group were extubated when standard criteria were met; T group patients had a TOF ratio of greater than 0.90 as an additional extubation criterion;and U group patiens were extubated when TOF ratio is greater than 0.90 and meanwhile transcutaneous partial pressure of carbon dioxide recovered to preoperative ±5mmHg .All the patients were transport to the PACU after extubation.Compare the adverse respiratory events at the moment of extubation, on the arrival of PACU, at 30min and 60min moment in the PACU respectively.

Three hundred aged(age>65y) patients were rondomized to acceleromyographic monitoring unit transcutaneous CO2 partial pressure(TcPCO2) monitoring(U group)or acceleromyographic monitering(T group)or conventional(C group).Anesthethic management was standardized.U patients were extubated when TOF ratio greater than 0.9 and transcutaneous CO2 partial pressure recover to preoprative (±5mmHg).T patients were extubated when TOF ratio greater than 0.9.C patients were extubated when standard criteria were met.Anesthesia monitoring, including ECG, invasive arterial pressure, pulse oxygen saturation, the BIS, nasopharyngeal temperature.The anesthesia induction with propofol 1 ~ 2 mg/kg, rocuronium 0.6 mg/kg, fentanyl 2 ug/kg, anesthesia maintained using propofol, fentanyl and the rocuronium 0.3 mg/kg. continuous pumping, maintain circulation stabilization and BIS value in 40 ~ 60, about 30 minutes before the end of surgery to stop rocuronium infusion, at the end of sewing leather to stop propofol and fentanyl infusion. Adjust Respiratory parameters, maintain breathe out co2 partial pressure at the scope of the 30 ~ 35 MMHG, using the variable temperature blanket insulation. All patients are monitored and give the muscle relaxant antagonists, pulling out endotracheal intubation, recording the TOF and TcPCO2 data when leaving the operating room . But during anesthesia management in group C, shielding TOF and TcPCO2 data to the anesthesiologists; T group during anesthesia management, shielding TcPCO2 data to the anesthesiologist; U set during anesthesia management, can according to the TOF and TcPCO2 data to management. All postoperative patients are sent into PACU, giving oxygen mask 3L/min, they can leave PACU Aldrete score nine points or more. By blind method principle, physicians of PACU,who is responsible for the patients with postoperative index records and statistics are blind to the staff for grouping, intraoperative management and BiBa tube drawing situation , in order to avoid bias. Statistical analysis: all the data represented as mean + / - standard deviation, using SPSS statistical software, measuring data comparison using analysis of variance between groups, count data using chi-square test, P < 0.05 that was statistically significant

Inclusion Criteria:

• Elective general anesthesia surgery elderly patients (age > 65 years), gastrointestinal surgery

Exclusion Criteria:

• ASA grade III or IV level, merging, bronchial asthma, chronic obstructive pulmonary disease, severe liver and kidney function is not complete (liver and kidney function corresponding biochemical index 50% above the normal level), neuromuscular disease, and use effect of neuromuscular transmission drugs or severe obesity (BMI > 35) of the patients