Driving Pressure-guided Tidal Volume Ventilation in the Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is associated with high mortality, some of which can be attributed to ventilator-induced lung injury (VILI) when artificial ventilation is not customized to the severity of lung injury. As ARDS is characterized by a decrease in aerated lung volume, reducing tidal volume (VT) from 12 to 6 mL/kg of predicted body weight (PBW) was shown to improve survival more than 20 years ago. Since then, the VT has been normalized to the PBW, meaning to the theoretical lung size (before the disease), rather than tailored to the severity of lung injury, i.e., to the size of aerated lung volume. During ARDS, the aerated lung volume is correlated to the respiratory system compliance (Crs). The driving pressure (ΔP), defined as the difference between the plateau pressure and the positive end expiratory pressure, represents the ratio between the VT and the Crs. Therefore, the ΔP normalizes the VT to a surrogate of the aerated lung available for ventilation of the diseased lung, rather than to the theoretical lung size of the healthy lung, and thus represents more accurately the actual strain applied to the lungs. In a post hoc analysis of 9 randomized controlled trials, Amato et al. found that higher ΔP was a better predictor of mortality than higher VT, with an increased risk of death when the ΔP \> 14 cm H2O. These findings have been confirmed in subsequent meta-analysis and large-scale observational data. In a prospective study including 50 patients, the investigators showed that a ΔPguided ventilation strategy targeting a ΔP between 12 and 14 cm H2O significantly reduced the mechanical power, a surrogate for the risk of VILI, compared to a conventional PBW-guided ventilation. In the present study, the investigators hypothesize that the physiological individualization of ventilation (ΔP-guided VT) may improve the outcome of patients with ARDS compared to traditional anthropometrical adjustment (PBW-guided VT)