What is PEEP, and why is it used in mechanical ventilation?

PEEP, or Positive End-Expiratory Pressure, is a mechanical ventilation strategy employed to prevent alveolar collapse at the end of expiration. By maintaining a certain level of pressure in the airways during this phase, PEEP helps keep the alveoli open, improving oxygenation and ventilation efficiency. This is particularly beneficial in conditions such as Acute Respiratory Distress Syndrome (ARDS) or other forms of respiratory failure where alveolar recruitment is necessary.

An important aspect of PEEP is its role in enhancing functional residual capacity (FRC) within the lungs, which contributes to better gas exchange and increases the surface area available for oxygen absorption. By preventing the collapse of alveoli, PEEP can help improve oxygenation without requiring higher inspired oxygen concentrations, thereby reducing the risk of oxygen toxicity.

While maintaining airway patency and influencing lung inflation times are related concepts, the primary purpose of PEEP is specifically aimed at preventing the collapse of alveoli, rather than enhancing exhalation or managing inflation times directly. Thus, the use of PEEP effectively addresses significant issues in mechanical ventilation and respiratory care by sustaining lung function and improving outcomes for patients.