determine the effect of prone positioning on ventilation and perfusion distribution in adults with acute respiratory distress syndrome by electrical impedance tomography

By intravenous injection of a small amount of normal saline, electrical impedance tomography enables evaluation of the pulmonary blood flow. EIT might be helpful in establishing the hypoxemia etiology at bedside via combining regional ventilation and perfusion information. The objective of this study was to describe the physiological effects of prone position on respiratory mechanics, ventilation and pulmonary perfusion in patients with ARDS.

Inclusion Criteria:

• patients who were undergoing mechanical ventilation with moderate-to-severe ARDS (defined as a Pao2:Fio2 ratio < 150 mm Hg with a positive end-expiratory pressure ≥ 5 cm of water, and an Fio2 of ≥ 0.6) according to the Berlin definition

Exclusion Criteria:

• contraindications to the use of EIT (e.g., presence of pacemaker or chest surgical wounds dressing)

Patients requiring mechanical ventilation are recieved prone position ventilation who admitted to the surgical ICU.