PEEP Titration Guided by Electrical Impedance Tomography in Laparoscopic Surgery The PEaRL Study

Overview

Background: Laparoscopic surgery has gained widespread adoption due to its minimally invasive nature, offering advantages such as reduced postoperative pain, shorter hospitalization, and faster functional recovery compared with traditional open surgery. Nevertheless, postoperative respiratory complications remain a major source of morbidity. Factors such as general anesthesia, the Trendelenburg position, and CO₂ pneumoperitoneum can impair respiratory mechanics, reduce total lung capacity, and promote atelectasis, leading to compromised gas exchange. Rationale: Positive end-expiratory pressure (PEEP) is routinely applied to prevent alveolar collapse and improve oxygenation during mechanical ventilation. However, the use of standardized, non-individualized PEEP levels may be suboptimal, as inappropriate settings can cause alveolar overdistension or persistent collapse. Personalized PEEP titration, tailored to patient-specific lung mechanics, has recently emerged as a promising strategy to minimize ventilator-induced lung injury (VILI). Methods and Tools: Electrical Impedance Tomography (EIT) is a non-invasive, bedside monitoring technique that enables real-time assessment of regional lung ventilation. By evaluating ventilated and non-ventilated lung areas, EIT can guide PEEP optimization and support individualized ventilatory management. Recent studies suggest that EIT-guided PEEP titration improves respiratory parameters and reduces atelectasis in patients undergoing major surgery. Objective: The present study aims to evaluate the efficacy of EIT-guided PEEP personalization in patients undergoing laparoscopic and robotic surgery. Primary endpoints include improvements in regional ventilation, respiratory system compliance, and intraoperative gas exchange, as well as postoperative pulmonary function.

Laparoscopic surgery has become an increasingly widespread surgical approach due to its minimally invasive nature, which allows for reduced postoperative pain, shorter hospital stays, and faster functional recovery compared to traditional open surgery. However, despite these advantages, laparoscopic procedures are not free from postoperative respiratory complications, which remain among the leading causes of postoperative morbidity. The combination of general anesthesia, the Trendelenburg position, and insufflation of CO₂ into the abdominal cavity can alter respiratory mechanics, reduce total lung capacity, and promote the development of atelectatic areas, resulting in impaired gas exchange (1-2). Positive end-expiratory pressure (PEEP) is a widely used strategy to prevent alveolar collapse and improve oxygenation during mechanical ventilation. Nevertheless, the application of a standardized, non-individualized PEEP level may not be optimal for all patients, and an inappropriate PEEP setting may lead to alveolar overdistension or persistence of collapsed areas (3). Recently, personalized PEEP titration has gained attention as a method to tailor ventilation settings to individual patient characteristics, thereby minimizing the risk of ventilator-induced lung injury (VILI) (4). Electrical Impedance Tomography (EIT) is a non-invasive, bedside imaging technique that enables real-time assessment of the regional distribution of pulmonary ventilation. EIT allows continuous monitoring of the effects of PEEP on both ventilated and non-ventilated lung regions and can guide the optimization of individualized PEEP levels to improve ventilation distribution and reduce the risk of respiratory complications (5-6). Recent studies have shown that the use of EIT-guided PEEP personalization in patients undergoing major surgery can improve respiratory parameters and reduce atelectasis formation (7-8). Specifically, EIT enables the performance of a PEEP trial, during which the device identifies areas of alveolar overdistension or collapse in response to PEEP changes, thereby guiding personalized ventilatory settings. However, the application of this technique in the context of laparoscopic surgery remains limited. This study aims to evaluate the effectiveness of EIT-guided PEEP personalization in patients undergoing laparoscopic and robotic procedures, with the goal of improving regional ventilation, respiratory system compliance, and intraoperative gas exchange, as well as postoperative pulmonary function.