Postoperative hypoxemia was persistent and common after surgery.Rapid diagnosis and subsequent therapeutic measures must be adopted by anesthesiologists.Lung ultrasound has been confirmed to be more sensitive and accurate for diagnosis of pulmonary ailment than chest radiography.The primary objective of the present study was to evaluate lung complications by bedside lung ultrasonography on patients suffered from hypoxemia after general anesthesia in the postoperative period.

Inclusion Criteria:

- at least 18 years of age, hypoxemia after general anesthesia ( definded as a SPO2 <92%,greater than 30s)

Exclusion Criteria:

• Covered with surgical dressings from opening thoracic and breast surgery, noncooperate from schizophrenia or delirium, a BMI higher than 40 kg/m2, unstable hemodynamics, dyspnea from residual opioids or muscle relaxants, hemoglobin of 8g/L or less, risk of bleeding, body temperature was more than 38℃ or less than 36℃

Parients in postoperative care unit(PACU) of 18 years at least and suffering from hypoxemia after general anesthesia and noncardiac surgeries were included in our study.