Background Pneumoperitoneum and extreme positioning during robotic surgery impose substantial mechanical load on the respiratory system. Whether bedside electrical impedance tomography (EIT) is beneficial for individualized positive end-expiratory pressure (PEEP) titration under routinely high-PEEP ventilation remains uncertain. We assessed the feasibility and benefits of EIT-guided PEEP titration during clinical routine and explored whether pre-EIT respiratory parameters or anthropometric variables can predict EIT-guided best PEEP and EIT endpoints: lung collapse reduction, overdistention reduction, and regional ventilation delay reduction in routine perioperative care. Materials and methods Prospective observational study in 177 patients undergoing elective robotic procedures spanning steep Trendelenburg (e.g., prostate/rectal) and non-Trendelenburg (e.g., adrenalectomy) positions with a laparoscopic pressure of 20 cmH2O. After establishing pneumoperitoneum and final positioning, EIT (OD–CL crossing-point method) was used to titrate PEEP. Primary endpoints were EIT-guided best PEEP and change in PEEP. Secondary endpoints were change in dynamic compliance (Cdyn), driving pressure (DP), and mechanical power (MP) normalized to Cdyn (MPadj), as well as EIT-derived endpoints: lung collapse reduction, overdistention reduction, and regional ventilation delay reduction. Associations between pre-EIT variables and outcomes were tested by correlations and ROC analysis. Results For the primary endpoints, EIT-guided PEEP increased pre-EIT PEEP from 12.0 ± 2.0 to 14.8 ± 2.1 cmH2O and, hence, by 2.8 ± 2.3 cmH2O. Of the secondary endpoints, Cdyn improved in 82% of the patients after EIT-guided PEEP titration. DP lowered in 31% of the patients, with post-EIT DP of ≤ 15 cmH2O. Despite mechanical gains, MPadj increased on average from 0.42 to 0.43 J·cmH2O·min−1ml−1. Concerning the EIT-derived endpoints, lung collapse reduction was 88%, overdistention reduction was 12%, and regional ventilation delay reduction was 30%. Proportions in secondary endpoints did not differ across surgical subgroups. Baseline anthropometrics showed poor predictive value for EIT-guided best PEEP (strongest correlation with MPadj: r = 0.33, R2 = 0.109) and change in PEEP (strongest correlation with the difference between laparoscopic pressure and PEEP (lap. pressure-PEEP), r = 0.38; R2 = 0.144). Pre-EIT Cdyn best signalled lung collapse reduction with an ROC-derived cutoff < 45.75 ml/H2O (accuracy 0.82, sensitivity 0.84, specificity 0.68). Discussion EIT-guided PEEP titration improved ventilation parameters in a heterogeneous robotic cohort with high abdominal pressure subject to high-PEEP, maintaining lung-protective ventilation. Pre-EIT respiratory data and anthropometric variables were insufficient for the reliable prediction of EIT-guided best PEEP. Our study demonstrates that EIT can be implemented in clinical routine and allows for individualization of respiratory treatment during robotic surgery, subject to high-PEEP ventilation. Clinical trial number Not applicable.

EIT-guided end-expiratory pressure individualization in robotic surgery with high PEEP ventilation: a prospective observational study

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2026年3月10日

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Lorenz L. Mihatsch,
Anja Gnadl,
Fiona Harzer,
Stefan Rederlechner,
Patrick Friederich

摘要

Background

Pneumoperitoneum and extreme positioning during robotic surgery impose substantial mechanical load on the respiratory system. Whether bedside electrical impedance tomography (EIT) is beneficial for individualized positive end-expiratory pressure (PEEP) titration under routinely high-PEEP ventilation remains uncertain. We assessed the feasibility and benefits of EIT-guided PEEP titration during clinical routine and explored whether pre-EIT respiratory parameters or anthropometric variables can predict EIT-guided best PEEP and EIT endpoints: lung collapse reduction, overdistention reduction, and regional ventilation delay reduction in routine perioperative care.

Materials and methods

Prospective observational study in 177 patients undergoing elective robotic procedures spanning steep Trendelenburg (e.g., prostate/rectal) and non-Trendelenburg (e.g., adrenalectomy) positions with a laparoscopic pressure of 20 cmH₂O. After establishing pneumoperitoneum and final positioning, EIT (OD–CL crossing-point method) was used to titrate PEEP. Primary endpoints were EIT-guided best PEEP and change in PEEP. Secondary endpoints were change in dynamic compliance (Cdyn), driving pressure (DP), and mechanical power (MP) normalized to Cdyn (MP_adj), as well as EIT-derived endpoints: lung collapse reduction, overdistention reduction, and regional ventilation delay reduction. Associations between pre-EIT variables and outcomes were tested by correlations and ROC analysis.

Results

For the primary endpoints, EIT-guided PEEP increased pre-EIT PEEP from 12.0 ± 2.0 to 14.8 ± 2.1 cmH₂O and, hence, by 2.8 ± 2.3 cmH₂O. Of the secondary endpoints, Cdyn improved in 82% of the patients after EIT-guided PEEP titration. DP lowered in 31% of the patients, with post-EIT DP of ≤ 15 cmH₂O. Despite mechanical gains, MP_adj increased on average from 0.42 to 0.43 J·cmH₂O·min⁻¹ml⁻¹. Concerning the EIT-derived endpoints, lung collapse reduction was 88%, overdistention reduction was 12%, and regional ventilation delay reduction was 30%. Proportions in secondary endpoints did not differ across surgical subgroups. Baseline anthropometrics showed poor predictive value for EIT-guided best PEEP (strongest correlation with MP_adj: r = 0.33, R² = 0.109) and change in PEEP (strongest correlation with the difference between laparoscopic pressure and PEEP (lap. pressure-PEEP), r = 0.38; R² = 0.144). Pre-EIT Cdyn best signalled lung collapse reduction with an ROC-derived cutoff < 45.75 ml/H₂O (accuracy 0.82, sensitivity 0.84, specificity 0.68).

Discussion

EIT-guided PEEP titration improved ventilation parameters in a heterogeneous robotic cohort with high abdominal pressure subject to high-PEEP, maintaining lung-protective ventilation. Pre-EIT respiratory data and anthropometric variables were insufficient for the reliable prediction of EIT-guided best PEEP. Our study demonstrates that EIT can be implemented in clinical routine and allows for individualization of respiratory treatment during robotic surgery, subject to high-PEEP ventilation.

Clinical trial number

Not applicable.