Continuous Positive Airway Pressure Decreased Lung Collapse During General Anesthesia Induction in Pediatric Patients

Patients will receive general anesthesia induction with CPAP at 5 cmH20 via face mask with a circular system. CPAP will use before extubation.The air-test will perform during anesthesia with transitory decreases inspired fraction of oxygen to 0.21 over a 5 min period. Recruitment maneuver will be perform if the air test is positive, ( SpO2 is ≤ 96%)