Pneumoperitoneum Pressure and Lung Ultrasound Atelectasis

Effects of Different Pneumoperitoneum Pressures on Perioperative Atelectasis Assessed by Lung Ultrasound in Laparoscopic Cholecystectomy: A Prospective Randomized Single-Blind Controlled Trial

Elective laparoscopic cholecystectomy may lead to perioperative atelectasis due to pneumoperitoneum-related diaphragmatic elevation and impaired respiratory mechanics. Lung ultrasound (LUS) provides a noninvasive bedside method for evaluating perioperative aeration loss. This prospective randomized controlled study aims to compare the effects of low-pressure (10 mmHg) and standard-pressure (14 mmHg) pneumoperitoneum on perioperative atelectasis assessed by LUS in patients undergoing laparoscopic cholecystectomy under general anesthesia. Changes in LUS scores, respiratory mechanics, oxygenation, and postoperative clinical outcomes will also be evaluated.

Elective laparoscopic cholecystectomy may cause perioperative atelectasis due to pneumoperitoneum-related impairment of respiratory mechanics. Lung ultrasound (LUS) is a noninvasive bedside tool that can evaluate perioperative lung aeration loss and atelectasis.

This prospective randomized single-blind controlled trial aims to compare the effects of low-pressure (10 mmHg) and standard-pressure (14 mmHg) pneumoperitoneum on perioperative atelectasis assessed by LUS in patients undergoing elective laparoscopic cholecystectomy under general anesthesia. Patients will be randomized into two groups according to pneumoperitoneum pressure level.

LUS assessments will be performed before pneumoperitoneum, at the end of surgery before extubation, and at the postoperative first hour. The primary outcome will be the change in LUS score from baseline to the end of surgery. Secondary outcomes will include respiratory mechanics, oxygenation parameters, postoperative oxygen requirement, postoperative pain, nausea-vomiting, and recovery outcomes.

Inclusion Criteria:

• Patients aged between 18 and 65 years
• ASA physical status I-II
• Scheduled for elective laparoscopic cholecystectomy under general anesthesia
• Body mass index (BMI) <30 kg/m²
• Ability to provide written informed consent

Exclusion Criteria:

• Chronic pulmonary disease
• Recent respiratory tract infection
• Thoracic deformity or previous thoracic surgery
• Preoperative pulmonary pathology
• Morbid obesity
• Pregnancy
• Emergency surgery
• Conversion to open surgery
• Requirement for protocol-violating pneumoperitoneum pressure modification
• Refusal to participate in the study