Does Positive Pressure Extubation Reduce Postoperative Desaturation?

This study tests a technique called positive pressure extubation — removing a breathing tube while briefly applying positive pressure — to reduce episodes of low oxygen levels (desaturation) immediately after surgery. This is a simple maneuver that could improve safety during post-surgical wakeup. You may be eligible if: - You are 18 to 75 years old - You are having scheduled (non-emergency) abdominal or urological surgery - You will need an arterial catheter for monitoring during surgery - You will be lying on your back during surgery - You are planned to be taken off the breathing tube in the operating room after surgery You may NOT be eligible if: - You have a BMI above 35 (severe obesity) - You are pregnant - You have a chronic or acute lung condition, or sleep apnea - You have had a difficult intubation or prior intubation problems - You cannot understand French Talk to your doctor to see if this trial is right for you.