What are complications of positive end-expiratory pressure (PEEP) in mechanical ventilation?

Updated: Sep 15, 2020
  • Author: Christopher D Jackson, MD; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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When used to treat patients with a diffuse lung disease, PEEP should improve compliance, decrease dead space, and decrease the intrapulmonary shunt effect. The most important benefit of the use of PEEP is that it enables the patient to maintain an adequate PaO2 at a low and safe concentration of oxygen (< 60%), reducing the risk of oxygen toxicity (see Complications of Mechanical Ventilation).

Because PEEP is not a benign mode of therapy and because it can lead to serious hemodynamic consequences, the ventilator operator should have a definite indication to use it. The addition of external PEEP is typically justified when a PaO2 of 60 mm Hg cannot be achieved with an FIO2 of 60% or if the estimated initial shunt fraction is greater than 25%. No evidence supports adding external PEEP during initial setup of the ventilator to satisfy misguided attempts to supply prophylactic PEEP or physiologic PEEP.

Many clinicians use the least-PEEP philosophy, which recommends using the lowest positive pressure that provides an adequate PaO2 with a safe FIO2. Another manner of selecting the optimal PEEP is based on identifying the low inflection point on the volume-pressure curve generated breath to breath by using modern mechanical ventilators. PEEP should be set 1-2 cm of water pressure above this measured low inflection point to obtain the optimal PEEP.

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