PEEP is best described as which of the following?

PEEP is best described as which of the following?

• A. Negative pressure to improve venous return
• B. Positive pressure to keep alveoli open
• C. Pressure used during exhalation
• D. Ventilator alarm threshold

Answer: (B)

PEEP is positive pressure applied at the end of expiration to keep alveoli open. By holding airway pressure above atmospheric level at the end of exhalation, PEEP prevents small airways and alveoli from collapsing, which helps recruit more lung units, increases functional residual capacity, and improves oxygenation. It can enhance gas exchange by reducing intrapulmonary shunting, making it especially helpful in conditions like acute respiratory distress or other causes of hypoxemia. However, pushing the pressure too high can reduce venous return and cardiac output or risk overdistension, so the level is carefully titrated. The other options don’t capture the defining feature of PEEP: maintaining positive pressure at end expiration to keep alveoli open.

PEEP is positive pressure applied at the end of expiration to keep alveoli open. By holding airway pressure above atmospheric level at the end of exhalation, PEEP prevents small airways and alveoli from collapsing, which helps recruit more lung units, increases functional residual capacity, and improves oxygenation. It can enhance gas exchange by reducing intrapulmonary shunting, making it especially helpful in conditions like acute respiratory distress or other causes of hypoxemia. However, pushing the pressure too high can reduce venous return and cardiac output or risk overdistension, so the level is carefully titrated. The other options don’t capture the defining feature of PEEP: maintaining positive pressure at end expiration to keep alveoli open.