The aim of this prospective, randomized, comparative, controlled clinical study is to compare laryngeal mask airway ProtectorTM with the endotracheal tube, regarding to the respiratory mechanical parameters during controlled mechanical ventilation and the prevalence of aspiration. Aspiration will be evaluated by detecting and quantifying pepsin (a marker of gastric aspiration) and α-amylase (a marker of salivary aspiration) in the bronchoalveolar lavage ( mini BAL) of patients ≥18 years old, ASA 1-2, undergoing selective low-risk surgery under general anesthesia in a lithotomy position.

Inclusion Criteria:

• Patients aged ≥18 years ASA1-2 who are to undergo planned urological surgery of low or intermediate severity, under general anesthesia in the lithotomy position.

Exclusion Criteria:

• patients < 18 years old.
• Patients who are going to undergo an emergency/urgent operation/ trauma patients.
• Maternal population.
• Patients who are not scheduled to receive general anesthesia, but some other type of anesthesia.
• Patients in whom LMA placement is contraindicated, such as patients at high risk for reflux and aspiration of gastric contents (eg, history of gastroesophageal reflux, hiatal hernia, pyloric stenosis, gastrointestinal obstruction, morbid obesity).
• Patients who meet at least one of the four RODS difficulty criteria.
• Contraindicated patients: administration of neuromuscular blockade, suppression of spontaneous respiration, and those with an indication for awake intubation or surgical airway.
• Patients who refuse to participate in the study.