Robotic prostate surgery is commonly performed under general anesthesia with carbon dioxide pneumoperitoneum and steep Trendelenburg positioning. These conditions may reduce lung volumes, impair respiratory mechanics, and increase the risk of atelectasis and postoperative pulmonary complications. Recruitment maneuvers combined with individualized positive end-expiratory pressure may improve intraoperative oxygenation and lung compliance; however, the optimal timing of recruitment maneuver application in robotic prostate surgery remains unclear.

This prospective randomized study aims to compare the effects of recruitment maneuver timing on postoperative pulmonary complications in adult patients undergoing elective robotic prostate surgery. Participants will be randomized into two groups. In the Supine Recruitment Group, the recruitment maneuver will be performed before carbon dioxide insufflation while the patient is in the supine position, followed by individualized PEEP determination. In the Trendelenburg Recruitment Group, the recruitment maneuver will be performed after pneumoperitoneum and Trendelenburg positioning, followed by individualized PEEP determination. Patients will be evaluated for postoperative pulmonary complications up to postoperative 72 hours or until discharge, whichever occurs first.

Laparoscopic and robotic surgeries performed with carbon dioxide insufflation may cause clinically relevant physiological changes affecting pulmonary function. Pneumoperitoneum increases intra-abdominal pressure and, together with Trendelenburg positioning, may reduce functional residual capacity, decrease lung compliance, and promote atelectasis. These changes may contribute to hypoxemia and postoperative pulmonary complications.

Recruitment maneuvers are used to reopen collapsed alveolar units and may improve oxygenation and respiratory mechanics when combined with appropriate PEEP. Decremental PEEP titration is one method used to determine an individualized PEEP level after a recruitment maneuver by gradually reducing PEEP while monitoring oxygenation, respiratory compliance, and hemodynamic parameters.

The present study will evaluate whether the timing of recruitment maneuver application affects postoperative pulmonary outcomes in patients undergoing robotic prostate surgery. The study will compare recruitment maneuver performed before insufflation in the supine position with recruitment maneuver performed after insufflation and Trendelenburg positioning. Both groups will undergo individualized PEEP determination after the recruitment maneuver.

Inclusion Criteria:

• Patients scheduled for elective robotic prostate surgery
• Age 18 years or older
• Body mass index between 18 and 35 kg/m²
• No cognitive impairment
• Ability to provide written informed consent

Exclusion Criteria:

• Age younger than 18 years
• Emergency surgery
• Preoperative oxygen requirement
• Cognitive impairment
• Refusal to participate in the study

Individual participant data will not be shared due to institutional data privacy regulations and participant confidentiality.

Participants and outcome assessors were masked to group allocation. The anesthesiologist performing the recruitment maneuver was not masked because of the nature of the intervention.