Surgical Positions and Postoperative Atelectasis: A Lung Ultrasound Study

The aim of this study is to prospectively evaluate the effect of surgical position on the development of postoperative atelectasis in patients undergoing surgery in supine, prone, lateral decubitus, and lithotomy positions using lung ultrasonography (LUS), and to investigate whether there is a difference between these positions.

Inclusion Criteria: * Being between 18-65 years of age * Having ASA I-III status * Planning elective surgery under general anesthesia * Agreeing to participate in the study and signing the consent form Exclusion Criteria: * Patients requiring emergency surgery * Patients with ASA IV or higher * Presence of a known serious preoperative lung disease (COPD, Asthma, Pneumonia, Pleural effusion, Pneumothorax, Interstitial lung disease, Bronchiectasis, etc.) * History of neuromuscular disease * Body Mass Index (BMI) \> 35 kg/m² (Morbid obesity) * Presence of chest wall deformity or skin lesions that would obstruct LUS imaging * Cases with an operative duration of less than 60 minutes or more than 300 minutes * Patients with a history of thoracotomy, sternotomy, or prior open thoracic surgery * Patients with alcohol or drug dependence * Patients with significant anemia * Patients who are pregnant or lactating * Patients who develop laryngospasm following extubation * Refusal to provide consent or inability to cooperate