What Is Positive End-Expiratory Pressure (PEEP)?

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Positive end-expiratory pressure (PEEP) is a treatment option for patients who are experiencing acute respiratory failure (having trouble breathing on their own). Acute respiratory failure can occur after surgery, a lung injury, as the result of an infection, or a blockage in the lungs caused by a pulmonary embolism (blood clot in the lungs).

Any of these causes can be serious enough to require intubation. In this procedure, a breathing tube is inserted in the mouth or nose and down the trachea (windpipe). The tube is connected to a machine to assist with breathing and ensure the blood is getting enough oxygen.

This article will explain what positive end-expiratory pressure is, how it works, when it is used, and the precautions that a healthcare provider will consider before recommending PEEP.

Close up of doctor wearing surgical gloves, holding oxygen mask over patient in operating theater

Caiaimage / Sam Edwards / Getty Images

Definition of Positive End-Expiratory Pressure

PEEP is used for patients supported by mechanical ventilation (breathing with the help of a machine). It provides positive pressure when a breath is exhaled to make sure that the air sacs in the lungs (alveoli) are getting enough oxygen.

Alveoli are small air spaces in the lungs where the exchange of oxygen and carbon dioxide (ventilation) occurs. When a person breathes normally, the lungs allow for the airways and alveoli to remain open. This occurs because a substance called a surfactant prevents alveoli from collapsing, allowing for proper oxygen exchange.

However, if the body's production of surfactants is interrupted, the lack of available surfactants causes the alveoli to collapse, leading to inadequate oxygen exchange. This is when mechanical ventilation is required.

PEEP is a function of mechanical ventilation that maintains pressure throughout the airways and alveoli to allow for oxygen exchange while giving the lungs the chance to heal.

How It Works

PEEP is available on most mechanical ventilators and is used for intubated people who require a machine to help them breathe and distribute oxygen to the blood. It is a ventilator setting designed to keep the smaller passages of the lungs, such as the alveoli, open during the expiratory, or breathing-out, phase.

PEEP is different from continuous positive airway pressure (CPAP), which is positive external pressure continuously administered through a face mask. CPAP mainly is used for people who have been diagnosed with obstructive sleep apnea and is designed to keep the windpipe open during sleep. PEEP works much further into the lungs than CPAP.

How It's Used

PEEP is used when a person needs mechanical ventilation because they are unable to breathe on their own. Healthcare providers often refer to this as acute respiratory failure. Common causes of acute respiratory failure include:

Depending on the severity of the respiratory failure, a person may need to be intubated and placed on a ventilator to distribute oxygen from the lungs to the blood while allowing the lungs to rest and heal.


PEEP can effectively manage acute respiratory failure and other lung conditions requiring breathing support. Keeping the airways and alveoli open is crucial for proper blood oxygenation and lung healing.

PEEP has potential complications and should be applied by a respiratory professional like a pulmonologist. The healthcare provider administering PEEP must balance the oxygenation needs against the amount of pressure required to keep the alveoli open without causing damage to the alveoli or lungs.

Complications of PEEP include:

  • Pneumothorax (a collapsed lung)
  • Increased pressure in the chest cavity, leading to additional ventilation complications
  • Reduced blood flow from the heart


Positive end-expiratory pressure (PEEP) keeps the airways and small lung spaces open to allow for adequate oxygenation when a person cannot breathe on their own. If the lungs cannot oxygenate properly, the individual may need to be intubated and placed on mechanical ventilation to allow the lungs time to heal. PEEP is a function of the mechanical ventilator that uses pressure to keep the airways and alveoli open to allow for proper oxygen exchange.

A Word From Verywell

It can be overwhelming and upsetting to be informed by your healthcare provider that you or a loved one has acute respiratory failure. It is important to consult with your healthcare provider to ensure proper management of your lung health. If you already have a lung condition, avoiding tobacco products and reducing alcohol use can improve lung health and prevent acute respiratory failure.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Gattinoni L, Collino F, Maiolo G, et al. Positive end-expiratory pressure: how to set it at the individual levelAnn Transl Med. 2017;5(14):288. doi:10.21037/atm.2017.06.64.

  2. American Lung Association. ARDS Treatment and Recovery.

  3. UpToDate. Positive end-expiratory pressure (PEEP).

  4. NIH National Cancer Institute. Alveoli.

  5. Critical Care Practitioner. Mechanical ventilation - PEEP (positive end expiratory pressure).

  6. StatPearls. Positive End Expiratory Pressure.

  7. National Heart, Lung, and Blood Institute. What is respiratory failure?

By Pamela Assid, DNP, RN
Pamela Assid, DNP, RN, is a board-certified nursing specialist with over 25 years of expertise in emergency, pediatric, and leadership roles.