ARDS Also known as DAD (diffuse alveolar disease) or ALI (acute lung injury) a variety of acute and diffuse infiltrative lesions which cause severe refractory arterial hypoxemia and life-threatening arrhythmias
Mediastinal and heart contents place more pressure on lungs when in supine position than when in prone
Predisposes to atelectasis
Turn from supine to prone position
May be sufficient to reduce inspired O 2 or PEEP
Fluid pools in dependent regions of lung
Effect of prone position on ventilation distribution. In the supine position, the distribution of ventilation is preferentially distributed to the ventral regions. When the patient is prone, the stiffness of the dorsal chest wall favors the distribution of ventilation to the dorsal regions, facilitating reinflation in this area.
With position change to prone, previously nondependent air-filled alveoli become dependent, perfusion becomes greater to air-filled alveoli opposed to previously fluid-filled dependent alveoli, thereby improving ventilation-perfusion matching.
No benefit in mortality
Benefits to Proning Before proning After proning