Overview

The purpose of this study is to evaluate whether an intraoperative positive end-expiratory pressures (PEEP) setting strategy aimed at minimizing the mechanical power delivered to the lungs via transpulmonary pressure improves postoperative outcomes in obese patients undergoing conventional laparoscopic or robotic-assisted surgery. The objectives are to determine whether this strategy reduces immediate postoperative hypoxemia, and to assess whether it mitigates lung injury as reflected by relevant blood biomarkers.

Eligibility

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