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

Condition(s) studied

Investigational drug(s) / intervention(s)

A PEEP trial performed with the PulmoVista® 500 (Dräger, Lübeck, Germany) is a procedure designed to identify the optimal level of positive end-expiratory pressure: During the trial, stepwise adjustments of PEEP are made while EIT provides real-time, bedside visualization of ventilation distribution across different lung regions. Typically, the protocol involves a recruitment maneuver followed by incremental and/or decremental PEEP steps (for example, in 2-3 cmH₂O intervals). At each step, EIT measures changes in regional impedance, which reflect variations in local lung aeration and ventilation. By analyzing these parameters, clinicians can determine the individualized "best PEEP", defined as the point at which alveolar collapse is minimized without causing significant overdistension. The optimal PEEP is then set for subsequent ventilation management.

Study summary

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.

Eligibility

Primary outcome measure(s)

• Static respiratory system compliance — - Baseline (after anesthesia induction) - T1 (After Trendelemburg position and induction of pneumoperitoneum) - T2 (After PEEP trial) - T3 (90 minutes after PEEP trial) - T4 (180 minutes after PEEP trial) - T5 (Before end of anesthesia)
  Respiratory system compliance is equivalent to tidal volume divided by the diiference between plateau and PEEP pressure. Unit of measurement is cmH2O/mL

Trial sites (1)

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