Inter‐Individual Variation in LUNG Mechanics Assessed by the Non‐Invasive PEEP ‐Step Method During Laparoscopic and Robotic Surgery Indicates Need for Individualized Ventilatory Settings

Background During laparoscopic surgery, abdominal carbon dioxide (CO 2 ) insufflation in the supine position and with head‐down tilt for robotic surgery increases abdominal pressure and pushes the diaphragm cranially. This causes a decrease in end‐expiratory lung volume and in lung and chest wall compliance. These effects can be counteracted by the application of PEEP. Our study aimed to measure lung and chest wall mechanics during laparoscopic surgery using a non‐invasive method (PEEP‐step method) and to determine the optimal PEEP level for each patient. Methods Thirty‐two patients scheduled for abdominal surgery participated in this observational study with pneumoperitoneum. Fourteen patients underwent surgery for pelvic conditions in head‐down position and 18 in supine position. Data from the ventilator was collected and analysed with a dedicated software, which calculated lung compliance and transpulmonary pressure from a two‐step PEEP increase. Measurements were performed after induction, after pneumoperitoneum in supine/tilt head‐down and before emergence. Results Lung and chest wall compliance decreased during CO 2 insufflation with high individual variation, and we observed a≈90% increase in transpulmonary driving pressure. After CO 2 ‐desufflation, lung and chest wall compliance returned to near baseline levels on a group level. However, 19 patients had a remaining reduction in lung compliance, six with 20%–50%. Optimal PEEP level calculated by the software was twice the clinical routine level. Conclusions The study found substantial individual variation in lung compliance during laparoscopic surgery in patients without evident lung disease. This variability does not align well with respiratory system compliance. The findings highlight the need for individualized ventilator settings based on lung‐ rather than respiratory system mechanics. The PEEP‐step method may be a non‐invasive, real‐time bedside tool to identify patients who would benefit from higher PEEP to preserve lung volume and possibly prevent postoperative complications. Editorial Comment Laparascopic surgical conditions can affect lung mechanics, though not always predictably. This study examined how a test of higher or lower PEEP directly after anaesthesia induction might inform PEEP optimization in the same cases undergoing laparoscopic surgery. Trial Registration ClinicalTrials.gov (NCT04484727, 2022‐05‐01)