Transpulmonary Driving Pressure in ARDS COVID19 Patients

A majority (65-85%) of critically ill patients admitted in intensive care units with a confirmed diagnostic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) developed an acute respiratory distress syndrome (ARDS) according to BERLIN criteria. Gattinoni et al. recently described that the ARDS related to SARS-CoV-2 was not a "Typical" ARDS. Patients affected by this infection present indeed a major hypoxemia, which was surprisingly associated in early phase with a high compliance of respiratory system, more than 50 ml/cm H2O in most cases. The cornerstone of current treatment in case of ARDS is the use of "lung protective" ventilation, including limited tidal volumes (VT), low end-inspiratory plateau pressures while maintaining sufficiently-high positive end-expiratory pressures (PEEP). However, high levels of PEEP in patients may have detrimental effects on hemodynamic status and fluid retention, particularly when the respiratory system compliance is normal. High PEEP may also lead to overdistension and an increase of alveolar dead space. The airway pressures commonly monitored does not reliably reflect the impact of pressures on the lung parenchyma. Elastance of chest wall may indeed largely influence values of airways pressions. In contrast, transpulmonary pressure obtained using esophageal pressure (Pes) directly reflect lung overdistension risk and lung properties. In order to better understand this new kind of ARDS characterized by modest recruitable profile and to better personalize mechanical ventilation setting and therapy it is obvious to precise transpulmonary pressure.