Auto-PEEP on Ventilator Waveforms

The waveform clue that matters most in obstructive ventilation may be the expiration that never finishes. When expiratory flow is still present as the next breath begins, gas remains trapped, end-expiratory alveolar pressure stays positive, and the next inspiration must overcome that pressure. This is auto-PEEP, also called intrinsic PEEP. Auto-PEEP can begin as a patient-ventilator synchrony problem and progress to dynamic hyperinflation, hypotension, or arrest. Read the flow tracing first, confirm the pressure only when the patient is passive, and correct the mismatch between delivered minute ventilation and available expiratory time. In Canada, ventilator-setting changes must follow provincial scope, prescriber orders, and institutional policy, with respiratory therapy involvement.