Fibrobronchoscopy; hypoxemia; mask After thoracic surgery, patients often require fibronectomy aspiration, but fibronectomy aspiration can decrease the patient’s oxygen saturation, aggravate hypoxia and lead to arrhythmias and ST-T segment changes, which can lead to death in severe cases [1], therefore, fibronectomy aspiration in elderly patients is greatly limited. In order to prevent the occurrence of severe acute hypoxia and improve the safety of fibronectomy aspiration, this study intends to evaluate the effect of using a self-designed modified reservoir mask in fibronectomy aspiration in elderly patients and provide a basis for its clinical application. I. Clinical data 1. General data: 40 patients after thoracic surgery from January 2006 to August 2006, 28 males and 12 females, aged 65-76 years old, average 69 years old, underwent 74 times of fibronectomy aspiration, randomly divided into two groups, 36 times in the nasal catheter oxygenation group and 38 times in the mask oxygenation group. 2. Homemade modified mask: A cross of about 5 mm radius was cut with a scalpel on the nasal side of the reservoir mask (Model 1202, Intersurgical, UK) for the tracheoscope to pass through. 3. Operation method: nasal catheter oxygen administration group was administered by nasal catheter at 10 L/min, and the mask oxygen administration group was administered by homemade modified mask at 10 L/min. Cardiac monitoring and transcutaneous oxygen saturation monitoring (IntellivueMP4, PHILIPS, The Netherlands) were performed during the fibronectomy aspiration. Fiberoptic bronchoscopy (XZ-3 type, Shanghai Medical Equipment Group Medical Optical Instrument Factory, Shanghai, China) was used for aspiration and/or lavage. 4. Statistical methods: t-test for numerical variables, χ2 test for categorical variables.