Understanding the setting of PEEP from esophageal pressure in patients with ARDS

Excerpt

The act of breathing during mechanical ventilation requires a driving force, which is generated, totally or in part, by contraction of the respiratory muscles and by the ventilator (controlled or assisted ventilation). This driving force must overcome the elastic and resistive properties of the respiratory system. Because the respiratory system is composed of lung and chest wall, in series, in order to know what pressure is distending the lung, it is necessary to measure the transpulmonary pressure [1]. The transpulmonary pressure is computed as the difference between airway and pleural pressures, where the distending force of the chest wall is the pleural pressure. Unfortunately, in clinical practice, the airway pressure is widely erroneously assumed to reflect the transpulmonary pressure, despite the fact that several studies have shown that the contribution of pleural pressure is often important and unpredictable [1]. …