Which of the following is true about positive end expiratory pressure (PEEP)?

AIIMS BBSR SNO - 2019

Medical Surgical Nursing

Easy

Appeared in: AIIMS BBSR SNO - 2019

Explanation

The primary mechanism of Positive End-Expiratory Pressure (PEEP) is to apply pressure at the end of exhalation, which acts as a splint to keep the alveoli open.
This action directly prevents the alveoli from collapsing, a condition known as atelectasis.
By preventing collapse and recruiting more alveoli, PEEP increases the functional residual capacity (FRC) and the surface area available for gas exchange, which is its main therapeutic goal.

Option A: While it is true that PEEP reduces venous return, this is considered a major adverse effect, not its primary therapeutic purpose. The question asks for a true statement, and in the context of multiple true options, the primary mechanism is the best answer.
Option B: Although PEEP does improve alveolar gas exchange, this is a therapeutic outcome that occurs as a direct result of preventing alveolar collapse. Preventing collapse is the more fundamental mechanism of action.
Option D: This statement is factually incorrect. PEEP establishes a baseline pressure that is above atmospheric pressure at the end of expiration. This elevates the pressure throughout the respiratory cycle, thereby increasing, not decreasing, the mean airway pressure.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physiology and effects of Positive End-Expiratory Pressure (PEEP) as background academic context rather than a clinical decision trigger.
Nurses are responsible for monitoring patients on mechanical ventilation with PEEP for both its therapeutic effects (improved oxygen saturation) and adverse effects.
A key nursing assessment is monitoring for signs of decreased cardiac output, such as hypotension, tachycardia, and reduced urine output, which can result from the reduced venous return caused by PEEP.
The level of PEEP is a critical setting that is carefully titrated by the healthcare team to maximize oxygenation while minimizing the risk of hemodynamic compromise and lung injury (barotrauma).

How to Approach the Question

First, read the question carefully to understand what it's asking. This question asks for a 'true' statement about PEEP.
Next, evaluate each option based on your knowledge of respiratory physiology and mechanical ventilation.
Recognize that in some nursing questions, multiple options may be factually correct. In such cases, you must identify the best or most correct answer.
Differentiate between a therapy's primary mechanism of action, its therapeutic outcome, and its side effects.
Option (C) describes the fundamental mechanism of how PEEP works. Option (B) is the desired result of that mechanism. Option (A) is a known side effect. Option (D) is factually incorrect.
Conclude that the primary mechanism of action is the most fundamental and therefore the best answer among the given choices.

Concept Tested & Keywords

Concept Tested: Physiology and effects of Positive End-Expiratory Pressure (PEEP)
Stem keywords: positive end expiratory pressure, PEEP
Lead-in keywords: true about

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