1. Recruitment-to-inflation ratio to assess response to PEEP during laparoscopic surgery: A physiologic study.
- Author
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Covotta, Marco, Claroni, Claudia, Torregiani, Giulia, Menga, Luca S., Venti, Emanuela, Gazzè, Gaetano, Anzellotti, Gian Marco, Ceccarelli, Valentina, Gaglioti, Pierpaolo, Orlando, Sara, Rosà, Tommaso, Forastiere, Ester, Antonelli, Massimo, and Grieco, Domenico L.
- Subjects
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LAPAROSCOPIC surgery , *RESPIRATORY mechanics , *PNEUMOPERITONEUM , *LUNG volume , *OPERATING rooms , *POSITIVE end-expiratory pressure - Abstract
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 2 O before and after pneumoperitoneum, at PEEP = 4 and 12 cmH 2 O during pneumoperitoneum. Pneumoperitoneum-induced derecruitment and PEEP-induced recruitment were assessed through a simplified method based on multiple pressure-volume curve. Dynamic and static strain changes were evaluated. R/I between 12 and 4 cmH 2 O was assessed from EELV. Inter-individual variability was rated with the ratio of standard deviation to mean (CoV). 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 2 O, PEEP = 12 cmH 2 O yielded variable amount of recruitment (139 mL [96–366] CoV = 101%), causing different extent of dynamic strain reduction (median decrease 0.02 [0.01–0.04], p = 0.002; CoV = 86%) and static strain increases (median increase 0.05 [0.04–0.07], p = 0.01, CoV = 33%). R/I (1.73 [0.58–3.35]) estimated the decrease in dynamic strain (p ≤0.001, r = −0.90) and the increase in static strain (p = 0.009, r = −0.73) induced by PEEP, while PEEP-induced changes in respiratory and lung mechanics did not. 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. • Optimal PEEP for laparoscopy is debated. Aeration loss and recruitment vary among patients, warranting personalized settings. • IIn this study, 17 patients undergoing robot-assisted prostatectomy during Trendelenburg pneumoperitoneum were studied. • Pneumoperitoneum variably reduced FRC. PEEP 12 cmH 2 0 yielded variable recruitment, leading to diverse effects on lung strain. • EELV-derived R/I well reflected the effect of PEEP on lung strain, identifying patients benefiting the most from higher PEEP. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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