Effect of Recruitment Maneuver on Postoperative Atelectasis Assessed by Lung Ultrasound in Laparoscopic Cholecystectomy

Perioperative atelectasis is a frequent consequence of general anesthesia and represents a major contributor to postoperative pulmonary complications. Anesthesia-induced loss of functional residual capacity, impaired diaphragmatic movement, and altered ventilation-perfusion matching predispose dependent lung regions to alveolar collapse. These effects are further amplified during laparoscopic surgery due to pneumoperitoneum-induced increases in intra-abdominal pressure, patient positioning, and the routine use of high fractions of inspired oxygen. Even in patients without preexisting pulmonary disease, these factors may result in clinically significant atelectasis during and after surgery.

Laparoscopic cholecystectomy is one of the most commonly performed minimally invasive surgical procedures and serves as a standardized clinical model to investigate perioperative respiratory strategies. Pneumoperitoneum and reverse Trendelenburg positioning during this procedure lead to cephalad displacement of the diaphragm, reduced lung compliance, and regional ventilation heterogeneity, thereby increasing the risk of perioperative atelectasis.

Alveolar recruitment maneuvers are ventilation strategies aimed at reopening collapsed alveoli by temporarily increasing transpulmonary pressure. When applied appropriately, recruitment maneuvers may improve lung aeration, enhance oxygenation, and increase respiratory system compliance. Several studies have demonstrated the beneficial effects of recruitment maneuvers during laparoscopic surgery; however, the optimal timing of these maneuvers remains controversial. The period immediately before extubation is particularly vulnerable to lung derecruitment, and applying a recruitment maneuver at this time may help restore lung aeration and reduce early postoperative atelectasis.

Lung ultrasound has emerged as a reliable, noninvasive, and bedside imaging modality for the assessment of lung aeration. The Lung Ultrasound Score (LUS) allows semi-quantitative evaluation of aeration loss by systematically examining predefined thoracic regions. LUS has been validated against computed tomography and has demonstrated high sensitivity in detecting perioperative atelectasis, making it well suited for use in the intraoperative and immediate postoperative period.

In this prospective clinical study, adult patients scheduled for elective laparoscopic cholecystectomy under general anesthesia will be evaluated to determine the effect of an alveolar recruitment maneuver applied immediately before extubation on perioperative atelectasis. Lung aeration will be assessed using lung ultrasound at predefined time points, and changes in the Lung Ultrasound Score will be used as the primary indicator of atelectasis. Secondary outcomes will include oxygenation parameters and basic respiratory variables.

This study aims to provide objective ultrasound-based evidence regarding the effectiveness of pre-extubation recruitment maneuvers in reducing perioperative atelectasis. The findings may contribute to the optimization of lung-protective ventilation strategies in routine anesthetic practice and support the integration of lung ultrasound into perioperative respiratory monitoring.

Inclusion criteria

• Adult patients scheduled for elective laparoscopic cholecystectomy under general anesthesia
• Age between 18 and 65 years
• Body mass index (BMI) < 30 kg/m²
• American Society of Anesthesiologists (ASA) physical status classification I-III
• Provision of written informed consent

Exclusion criteria

• Refusal to participate in the study
• Emergency surgical procedures
• Body mass index (BMI) ≥ 30 kg/m²
• American Society of Anesthesiologists (ASA) physical status classification IV