Mechanical Ventilation in Obese Surgical Patients

Inclusion Criteria: 1. Age ≥ 18 years; 2. Body Mass Index (BMI) ≥ 35 kg/m2; 3. Scheduled for laparoscopic surgery expected to exceed 2h (from incision to closure) under general anesthesia, as determined pre-operatively by the attending surgeon and surgical team based on typical scheduling estimates, prior experience, procedure type, planned surgical approach, and patient-specific factors. Exclusion Criteria: 1. Previous lung surgery; 2. Invasive mechanical ventilation for \>30 minutes within the last 30 days prior to surgery; 3. Receipt of immunosuppressive medication (chemotherapy or radiotherapy) up to two months prior to surgery; 4. Neurological procedures or cardiac surgery; 5. Need for one-lung ventilation or planned re-intubation following surgery; 6. Requirement for intraoperative prone or lateral decubitus positioning; 7. Enrollment in another interventional study or refusal to give written informed consent; 8. Pregnancy, determined by anamnesis and/or laboratory testing; 9. Persistent hemodynamic instability or intractable shock, considered hemodynamically unsuitable for the study by the patient's managing physician; 10. Severe chronic obstructive pulmonary disease (COPD, defined as non-invasive ventilation and/or oxygen therapy at home or repeated systemic corticosteroid therapy for acute exacerbations of COPD); 11. Severe cardiac disease (defined as New York Heart Association class III or IV, acute coronary syndrome or persistent ventricular tachyarrhythmia); 12. Acute respiratory distress syndrome (according to the Berlin definition 2) expected to require prolonged postoperative mechanical ventilation; 13. Severe pulmonary arterial hypertension (defined as systolic pulmonary artery pressure \> 40 mmHg) 14. Intracranial injury, intracranial tumor, or neuromuscular disease; 15. Known esophageal disease or anatomy that would preclude the safe placement of a standard orogastric tube