Lung Ultrasound Evaluation of Individualized Versus Standard PEEP on Postoperative Atelectasis in Gynecological Laparoscopy

Evaluation of the Effect of Driving Pressure-Guided Individualized PEEP Titration Versus Standard PEEP on Early and Late Postoperative Atelectasis Development Using Lung Ultrasonography in Gynecological Laparoscopic Surgeries

The purpose of this study is to compare two different airway pressure (PEEP) strategies during gynecological laparoscopic surgery to see which one better prevents lung collapse (atelectasis). We will compare a 'standard' fixed pressure with a 'personalized' pressure adjusted according to the patient's own lung mechanics (driving pressure). We will use lung ultrasound to check the lungs before surgery, 1 hour after surgery, and 24 hours after surgery to evaluate the results.

In this prospective observational study, we investigate the impact of PEEP strategies on lung collapse (atelectasis) in patients undergoing gynecological laparoscopy. The Standard Group receives a routine clinical application of 5 cmH2O PEEP. The Individualized Group undergoes a PEEP titration protocol where PEEP starts at 20 cmH2O and is adjusted to reach the optimal level based on the lowest driving pressure. To measure the results, a 12-zone Lung Ultrasonography (LUS) scoring system (0-3 points per zone) is utilized. Evaluations are conducted preoperatively (baseline), 1 hour postoperatively (early phase), and 24 hours postoperatively (late phase) to track the development and resolution of atelectasis.

Inclusion Criteria:

• Female patients aged between 18 and 65 years.
• American Society of Anesthesiologists (ASA) physical status I, II, or III.
• Scheduled for elective laparoscopic gynecological surgery (e.g., hysterectomy, myomectomy, sacrocolpopexy).
• Planned to undergo general anesthesia with endotracheal intubation.
• Expected surgery duration of 2 hours or more.
• Body Mass Index (BMI) ≤ 35 kg/m².

Exclusion Criteria:

• History of moderate-to-severe Chronic Obstructive Pulmonary Disease (COPD), clinically significant interstitial lung disease, or severe restrictive lung disease.
• New York Heart Association (NYHA) class III-IV heart failure, Ejection Fraction (EF) < 35%, or severe valvular disease.
• Advanced arrhythmia or hemodynamic instability (requiring high-dose vasopressor support).
• History of respiratory failure requiring mechanical ventilation within the past 4 weeks.
• Clinically or radiologically confirmed lower respiratory tract infection (e.g., pneumonia) within the past 1 month.
• Presence of thoracic deformity, large surgical dressings, severe subcutaneous emphysema, or any condition that hinders lung ultrasound evaluation.
• Pre-existing significant atelectasis or lung consolidation (defined as a score of 3 for consolidation or ≥2 zones with a score of ≥2 on preoperative LUS).
• Expected inability to perform the 24-hour postoperative ultrasound measurement (e.g., due to early discharge).