Upper airway endoscopy (micro laryngoscopy (MLS), pan endoscopy) is a minor upper airway procedure needing short duration general anesthesia, small calibrate endotracheal tube and manipulation of the airway. Because of airway manipulation and the surgery involves the airway, which is being shared with the anesthesiologist, there is a risk of interruption of ventilation, oxygenation and loss of airway in addition to inherent complications of surgery.~Methods:~After the patients will receive information about the study and informed consent will be taken. The patients will be randomized. In the control group, (group A) ventilation will be performed according to the routine big endotracheal tube. In the treatment group (group B), the ultra-thin ventilation tube will be placed using laryngoscopy. All other treatment will be unchanged. Data collection will be started 5 min after the initiation of the study. Demographic data, Past medical history, and examinations data will be collected after acceptance of the patient to be enrolled into the study and other ventilation parameters will be collected 5 min after the start of the the study which is Skin incision Primary endpoint is; to evaluate whether the Flow Controlled Ventilation (FCV) can also achieve adequate oxygenation and ventilation through small tube or not.
Ventilation through the small endotracheal tube is not an uncommon situation. The indications for it differ from elective upper airway surgery to emergency ventilation through needle cricothyrotomy. Conventionally, ventilation through small endotracheal tubes has been challenging by jet ventilation with subsequent risk of barotrauma and inadequate gas exchange. Expiration during jet ventilation occurs passively.