Mechanical Power Normalized to Compliance in Patients With Acute Respiratory Distress Syndrome

In patients with acute respiratory distress syndrome (ARDS), undergoing mechanical ventilation (MV), each respiratory cycle transfers a specific amount of mechanical energy to the lung, aimed to expand and overcome airway resistance. The total mechanical energy multiplied by the respiratory rate (RR) defines the mechanical power (MP). It has been hypothesized that a smaller functional lung size, often referred to as "baby lung" (BL), increases mechanical energy transfer that exacerbates lung damage. Functional lung size (BL) is associated with respiratory system compliance (Crs). Whatever the size of this operational BL, protective ventilation strategies should be aimed at preserving its size and functionality, to avoid ventilator-induced lung injury (VILI). For this reason, MP normalized to Crs (MP/Crs) could be an important parameter to evaluate. Preclinical studies have found that VILI arises primarily from a combination of MP components and not from any of its components individually. We believe that MP/Crs should have the same behavior in relation to MP components as a whole. Therefore, the objectives of this study are to compare variables according to the MP/Crs cut-off point and to identify the MP components associated with MP/Crs.