The participants will be randomly allocated to either SJOV or nasal cannula oxygen supply in a 1:1 ratio using block randomization with variable block sizes of four or six randomized. In the nasal cannula oxygen supply group, oxygen supplementation at 2 liters min-1 is delivered via a nasal cannula. In the SJOV group, SJOV is conducted using a Wei nasal jet tube (WNJ, Well Lead Medical Co. Ltd, Guangzhou, China) which is connected to a manual jet ventilator (Well Lead Medical Co. Ltd, Guangzhou, China) via its jet port.
This study aims to determine whether the use of SOJV could reduce the rate of hypoxia during gastrointestinal endoscopic procedures in deeply sedated patients sedated at high altitude comparing to the supplemental oxygen administration via nasal cannula.