IRCT20150107020592N21 IRCT 2019-06-23 Vice chancellor for research, Shahid Beheshti University of Medical Sciences Effect of Nasal High-Flow oxygen therapy on respiratory performance in ICU after bariatric surgery Effect of Nasal High-Flow oxygen therapy on respiratory performance in ICU after bariatric surgery 2019-03-18 anticipated 116 Complete https://irct.ir/trial/38845 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: The randomization of the two groups is based on the even and the odd numbers, the even numbers belong to the intervention group and The odd numbers belong to patients in the control group, Blinding description: Laboratory, clinical and radiological evidence is collected by people who do not have the type of intervention.The analysis is done by someone else who does not have the type of intervention. 3 Patients undergoing laparoscopic surgery for gastrectomy. Intervention 1: First Intervention group: After recovery, the patients are immediately treated with CPAP mask (CmH2O) 8-12 and surgical ICU is continued for at least 8 hours. Intervention 2: Second intervention group: After recovery, the patients immediately receive oxygen therapy through HIGH FLOW NASAL (OPTIFLOW) with FIO2: 50% and FLOW45-55 L / MIN, and they continue to undergo surgery for at least 8 hours. No - There is not a plan to make this available Justification or reason for not sharing IPD is I do not have a program