What is intrinsic positive end-expiratory pressure (PEEP), or auto-PEEP, in mechanical ventilation?

Updated: Apr 11, 2019
  • Author: Christopher D Jackson, MD; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Answer

Answer

Intrinsic positive end-expiratory pressure (PEEP) or auto-PEEP is a complication of mechanical ventilation that most frequently occurs in patients with COPD or asthma who require prolonged expiratory phase of respiration. These patients may have difficulty in totally exhaling the ventilator-delivered tidal volume before the next machine breath is delivered. When this problem occurs, a portion of each subsequent tidal volume may be retained in the patient's lungs, a phenomenon sometimes referred to as breath stacking (see image below). If this goes unrecognized, the patient's peak airway pressure may increase to a level that results in barotrauma, volutrauma, hypotension, patient-ventilator dyssynchrony, or death.

The flow to time waveform demonstrating auto–posit The flow to time waveform demonstrating auto–positive end-expiratory pressure (auto-PEEP).

Manometry performed by using an esophageal balloon to record changes in pleural pressure is the most accurate way to recognize intrinsic PEEP. However, this technology is not available at most institutions. Therefore, clinicians must anticipate this complication and carefully monitor the measured peak airway pressure. When intrinsic PEEP is diagnosed, the patient should temporarily be released from mechanical ventilation to allow for full expiration. The ventilator can then be adjusted to shorten inspiration by decreasing the set tidal volume, increasing the inspiratory flow rate, or reducing the frequency of respirations. These maneuvers, if performed properly, can increase the expiratory time. The normal inspiratory to expiratory ratio (I:E ratio) is 1:2. In patients with obstructive airway disease, the target I:E ratio should be 1:3 to 1:4.


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