Individualized PEEP without recruitment maneuvers improves intraoperative oxygenation: A randomized controlled study

Background: Individualized positive end-expiratory pressure (PEEP) combined with recruitment maneuvers improves intraoperative oxygenation in individuals undergoing robot-assisted prostatectomy. However, whether electrical impedance tomography (EIT)-guided individualized PEEP without recruitment maneuvers could also improve intraoperative oxygenation is unknown. Methods Fifty-six male patients undergoing elective robotic assisted laparoscopic prostatectomy were randomly assigned to either individualized PEEP (Group PEEP IND , n  = 28) or control with fixed PEEP of 5 cmH 2 O (Group PEEP 5 , n  = 28). Individualized PEEP was guided by EIT after placing the patients in Trendelenburg position and intraperitoneal insufflation. Patients in Group PEEP IND maintained the individualized PEEP without intermittent recruitment maneuvers and those in Group PEEP 5 maintained PEEP of 5 cmH 2 O intraoperatively. Both groups were extubated in a semi-sitting position once the extubation criteria was met. The primary outcome was the arterial oxygen partial pressure (PaO 2 ) / inspiratory oxygen fraction (FiO 2 ) prior to extubation. Other outcomes included intraoperative driving pressure, plateau pressure and dynamic respiratory system compliance, and the incidence of postoperative hypoxemia in post-operative care unit (PACU). Results The intraoperative median PEEP IND was 16 cmH 2 O (ranging from 12 to18 cmH 2 O). EIT-guided PEEP IND was associated with higher PaO 2 /FiO 2 before extubation compared to PEEP 5 (71.6 ± 10.7 vs . 56.8 ± 14.1, P  = 0.003). The improved oxygenation extended into the PACU with lower incidence of postoperative hypoxemia (3.8% vs. 26.9%, P  = 0.021). Additionally, PEEP IND was associated with lower driving pressures (12.0 ± 3.0 vs . 15.0 ± 4.4 cmH 2 O, P  = 0.044) and better compliance (44.5 ± 12.8 vs . 33.6 ± 9.1 ml/cmH 2 O, P  = 0.017). Conclusion Individualized PEEP guided by EIT without intraoperative recruitment maneuvers improved perioperative oxygenation in patients undergoing robot-assisted laparoscopic radical prostatectomy. Trial registration: China Clinical Trial Registration Center Identifier: ChiCTR2100053839. Registered 01/12/2021. First patient recruited on 15/12/2021. http://www.chictr.org.cn/showproj.aspx?proj=141373.