Abstract Rationale Robot assisted laparoscopic prostatectomy (RALP) involves steep trendelenburg positioning and pneumoperitoneum, which can impair pulmonary mechanics and gas exchange. Optimal positive end-expiratory pressure (PEEP) may mitigate these effects, but standardized settings may not reflect individual lung physiology. This study evaluated the impact of individualized PEEP guided by electrical impedance tomography (EIT) on intraoperative ventilation and gas exchange. Methods In this single-center randomized controlled trial, 42 patients undergoing RALP were included in the final analysis to either a control group with fixed PEEP of 5 cmH2O or an intervention group with individualized PEEP determined by EIT. General anesthesia was maintained with desflurane in both groups. All patients were ventilated using pressure-controlled ventilation with autoflow (PCV-AF) mode, targeting a tidal volume of 7 mL/kg of predicted body weight and FiO2 fixed at 0.4. Pneumoperitoneum was maintained at 12 mmHg and steep Trendelenburg positioning (∼40°) was applied uniformly. In the intervention group, individualized PEEP was titrated after Trendelenburg positioning with pneumoperitoneum and applied throughout that period. Primary outcome was the PaO2/FiO2 ratio (P/F ratio) at the end of the surgery (T3). Secondary outcomes included driving pressure (extracted from the ventilator at T1, T2-1, T2-2, and T3), PaCO2, oxygen reserve index (ORI), and global inhomogeneity index (GI) (each measured at three time points: T1, T2, and T3). Data were analyzed using linear mixed models with post-hoc comparisons. Results The intervention group showed significantly higher P/F ratios across time points (P = 0.037), with improved oxygenation at T3. Driving pressure was markedly lower in the intervention group during pneumoperitoneum, with peak driving pressures of 14.6 ± 2.3 cmH2O in the intervention group vs. 22.1 ± 2.3 cmH2O in controls (P 0.001). PaCO2 was transiently elevated in the intervention group at T2 (42.9 ± 3.5 vs. 38.2 ± 3.1 mmHg, P 0.01), but decreased by T3, while control values continued to rise (group × time interaction P 0.001). ORI showed overall significance (P = 0.029), without pairwise differences. GI was significantly lower in the intervention group (P = 0.041), indicating improved homogeneity at T3 (P = 0.046). Median individualized PEEP was 17 cmH2O (IQR: 16-18). Conclusions EIT-guided Individualized PEEP improves intraoperative oxygenation and reduces driving pressure during RALP. These findings support personalized ventilation strategies to minimize mechanical stress and enhance gas exchange under steep Trendelenburg positioning and pneumoperitoneum. This abstract is funded by: None
Lee et al. (Fri,) studied this question.
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