Background: Robot-assisted laparoscopic radical prostatectomy requires general anaesthesia, extreme Trendelenburg positioning and capnoperitoneum. Together these promote impaired pulmonary gas exchange caused by atelectasis and may contribute to postoperative pulmonary complications. In morbidly obese patients, a recruitment manoeuvre (RM) followed by individualised PEEP improves intraoperative oxygenation and end-expiratory lung volume (EELV). We hypothesised that individualised PEEP with initial RM similarly improves intraoperative oxygenation and EELV in nonobese individuals undergoing robot-assisted prostatectomy. Methods: Forty males (age, 49e76 yr; BMI <30 kg m À2 ) undergoing prostatectomy received volume-controlled ventilation (tidal volume 8 ml kg À1 predicted body weight). Participants were randomised to either (1) RM followed by individualised PEEP (RM/PEEP IND ) optimised using electrical impedance tomography or (2) no RM with 5 cm H 2 O PEEP. The primary outcome was the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO 2 /F i O 2 ) before the last RM before extubation. Secondary outcomes included regional ventilation distribution and EELV which were measured before, during, and after anaesthesia. The cardiovascular effects of RM/PEEP IND were also assessed. Results: In 20 males randomised to RM/PEEP IND , the median PEEP IND was 14 cm H 2 O [inter-quartile range, 8e20]. The PaO 2 / F i O 2 was 10.0 kPa higher with RM/PEEP IND before extubation (95% confidence interval [CI], 2.6e17.3 kPa; P¼0.001). RM/ PEEP IND increased end-expiratory lung volume by 1.49 L (95% CI, 1.09e1.89 L; P<0.001). RM/PEEP IND also improved the regional ventilation of dependent lung regions. Vasopressor and fluid therapy was similar between groups, although 13 patients randomised to RM/PEEP IND required pharmacological therapy for bradycardia. Conclusion: In non-obese males, an individualised ventilation strategy improved intraoperative oxygenation, which was associated with higher end-expiratory lung volumes during robot-assisted laparoscopic prostatectomy. Clinical trial registration: DRKS00004199 (German clinical trials registry)

(1) Background: Individual PEEP settings (PEEPIND) may improve intraoperative oxygenation and optimize lung mechanics. However, there is uncertainty concerning the optimal procedure to determine PEEPIND. In this secondary analysis of a randomized controlled clinical trial, we compared different methods for PEEPIND determination. (2) Methods: Offline analysis of decremental PEEP trials was performed and PEEPIND was retrospectively determined according to five different methods (EIT-based: RVDI method, Global Inhomogeneity Index [GI], distribution of tidal ventilation [EIT VT]; global dynamic and quasi-static compliance). (3) Results: In the 45 obese and non-obese patients included, PEEPIND using the RVDI method (PEEPRVD) was 16.3 ± 4.5 cm H2O. Determination of PEEPIND using the GI and EIT VT resulted in a mean difference of −2.4 cm H2O (95%CI: −1.2;−3.6 cm H2O, p = 0.01) and −2.3 cm H2O (95% CI: −0.9;3.7 cm H2O, p = 0.01) to PEEPRVD, respectively. PEEPIND selection according to quasi-static compliance showed the highest agreement with PEEPRVD (p = 0.67), with deviations > 4 cm H2O in 3/42 patients. PEEPRVD and PEEPIND according to dynamic compliance also showed a high level of agreement, with deviations > 4 cm H2O in 5/42 patients (p = 0.57). (4) Conclusions: High agreement of PEEPIND determined by the RVDI method and compliance-based methods suggests that, for routine clinical practice, PEEP selection based on best quasi-static or dynamic compliance is favorable.