Q: Patient in prone position should be given higher than usual Positive End Expiratory Pressure (PEEP) to correct ventilation/perfusion (V/Q) mismatch? (select one)
Higher PEEP in patients with prone position while on a ventilator, may make V/Q mismatch worse. Higher applied PEEP in prone position redistribute blood flow to the dependent portion of the lung which is ventral portion in prone position, causing out of proportion redistribution of ventilation, resulting in worsening of V/Q mismatch.
This is in contrast to regular supine patients where applied PEEP causes a homogeneous redistribution of ventilation and blood flow to the dependent portion, which is dorsal in this case.
Petersson J, Ax M, Frey J, et al. Positive end-expiratory pressure redistributes regional blood flow and ventilation differently in supine and prone humans. Anesthesiology 2010; 113:1361.