Positive end expiratory pressure (PEEP) is used in COPD patients to counteract the intrinsic PEEP (PEEPi), which represents the end expiratory recoil pressure of the total respiratory system due to the presence of dynamic hyperinflation (DH).
DH commonly occurs in COPD, where the presence of expiratory flow-limitation (EFL) requires the patient to breath at higher lung volumes to produce the necessary after appropriate leak correction, showed a sensitivity and specificity in detecting EFL expiratory flow. To be effective, the PEEP level applied to the patient should be equal to PEEPi.
The continuous monitoring of EFL could be a useful tool to select the minimum PEEP level required to abolish it.
EFL can be detected using the forced oscillation technique (FOT) by an index which quantifies, for each breath, the within-breath variations of respiratory reactance (delta Xrs) at 5Hz.
