Is abdomen release really necessary for prone ventilation in acute respiratory distress syndrome?

Prone ventilation for refractory acute respiratory distress syndrome (ARDS) mandates free abdomen by rolls in between chest wall and pelvic bones for better ventilation and control of airway pressure. We observed that, in patients with severe ARDS, prone ventilation with movable free abdomen produced high plateau pressure reduced by applying simple support to abdominal wall. Here, we have proposed a possible hypothesis to explain the paradoxical event in this particular group of patients. The increased alveolar volume in prone position is counteracted by reduction in rib cage diameter caused by weight of abdomen. In patients with severe ARDS in prone position, gravitational pressure transmits through abdominal support, resulting in better chest wall expansion and leading to more oxygenation and opening of the alveoli in ventral lung along with the dorsal lung portion that is usually better ventilated in prone position. There is no clinical trial regarding this particular observation. We suggest randomized trials to prove our observational findings.