Postoperative Pulmonary Complications Between Patients Undergoing Abdominal Surgery in Plateau and Plain Areas

Exclusion Criteria

• •1. Patients and their family members refused to be enrolled；
• •2. patients were unable to communicate because of language disorders such as dementia and hearing impairment；
• •3. patients were admitted to ICU 48 hours before operation；
• •4. preoperative diagnosis of ARDS, aspiration pneumonia, pulmonary embolism or pulmonary edema or other acute respiratory diseases；
• •5. mechanical ventilation within one week before operation；
• •6. death or discharge within 24 hours after operation；
• •7. second operation due to postoperative complications