Recruitment-to-inflation ratio to assess response to PEEP during laparoscopic surgery: A physiologic study.

During laparoscopic surgery, the role of PEEP to improve outcome is controversial. Mechanistically, PEEP benefits depend on the extent of alveolar recruitment, which prevents ventilator-induced lung injury by reducing lung dynamic strain. The hypotheses of this study were that pneumoperitoneum-induced aeration loss and PEEP-induced recruitment are inter-individually variable, and that the recruitment-to-inflation ratio (R/I) can identify patients who benefit from PEEP in terms of strain reduction. Sequential study. Operating room. Seventeen ASA I-III patients receiving robot-assisted prostatectomy during Trendelenburg pneumoperitoneum. Patients underwent end-expiratory lung volume (EELV) and respiratory/lung/chest wall mechanics (esophageal manometry and inspiratory/expiratory occlusions) assessment at PEEP = 0 cmH Pneumoperitoneum reduced EELV by (median [IqR]) 410 mL [80-770] (p < 0.001) and increased dynamic strain by 0.04 [0.01-0.07] (p < 0.001), with high inter-individual variability (CoV = 70% and 88%, respectively). Compared to PEEP = 4 cmH Trendelenburg pneumoperitoneum yields variable derecruitment: PEEP capability to revert these phenomena varies significantly among individuals. High R/I identifies patients in whom higher PEEP mostly reduces dynamic strain with limited static strain increases, potentially allowing individualized settings.

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Déclaration de conflit d'intérêts

Declaration of competing interest DLG reports speaking fees or support for travel expenses by GE Healthcare, Intersurgical, Fisher and Paykel, Gilead and Pfizer. MA has received personal fees from Maquet, and a research grant by Toray. DLG and MA disclose a research grant by General Electric Healthcare.