Abstract

ABSTRACT Objective: To evaluate the impact of an ascending positive end-expiratory pressure titration strategy on respiratory mechanics and mechanical power in patients without lung injury. Methods: An incremental positive end-expiratory pressure titration was performed in 4cmH2O steps, starting from zero end-expiratory pressure and progressing to 16cmH2O. Differences (Δ) in respiratory system static compliance, plateau pressure, driving pressure, and mechanical power were assessed during lung-protective ventilation. Mechanical power formulas proposed by Gattinoni et al. and Costa et al. were used. Analyses were also performed on the static elastic components, dynamic elastic components, total elastic power, and resistive components. Results: Increasing positive end-expiratory pressure levels were associated with a progressive rise in mechanical power, plateau pressure, total and static elastic power, and a decline in compliance. Mechanical power showed strong positive correlations with: ΔPplat (p < 0.001); Δelastic dynamic power (p < 0.001); Δdriving pressure (p < 0.001); and Δtotal elastic power (p < 0.001). Δmechanical power correlated strongly with Δresistive power (p < 0.001), but not with other mechanical power components or mechanics. Conclusion: Progressive positive end-expiratory pressure increase in patients without lung disease significantly raises total mechanical power and its elastic components, particularly static elastic power. These changes may occur silently and without significant alterations in driving pressure or compliance.