Ventilator triggering in presence of intrinsic positive end-expiratory pressure (PEEPi)

Recordings of tidal volume, flow, airway pressure (P_aw), and esophageal pressure (P_es) in a patient with chronic obstructive pulmonary disease receiving pressure support ventilation. Approximately half of the patient's inspiratory efforts do not succeed in triggering the ventilator. Triggering occurred only when the patient generated a P_es ≤8 cm H₂O (indicated by the horizontal line), which was equal in magnitude to the opposing elastic recoil pressure.