Progressive Care Nursing Certification (PCCN) Practice Exam

Which of the following does PEEP therapy specifically NOT improve?

1. Oxygenation

2. Atelectasis resolution

3. CO2 elimination

4. FiO2 support reduction

The correct answer is: CO2 elimination

PEEP, or Positive End-Expiratory Pressure, is a mode of mechanical ventilation that improves oxygenation and helps maintain the end-expiratory lung volume. This helps prevent alveolar collapse (atelectasis) and enhances overall lung function. When PEEP is applied, it increases the volume of air left in the lungs after exhalation, which improves the surface area available for gas exchange and effectively enhances oxygenation. It allows for better ventilation-perfusion matching and can significantly aid in resolving atelectasis by keeping the alveoli open, facilitating better oxygenation and reducing the need for a higher fraction of inspired oxygen (FiO2). However, while PEEP can improve oxygenation and reduce the work of breathing, it does not specifically improve the elimination of carbon dioxide (CO2). In fact, in some patients, especially those with certain conditions like COPD or those who are already hypercapnic, applying higher levels of PEEP may impair CO2 clearance due to reduced tidal volume and ventilation efficiency. This is because PEEP can hinder the ability to fully exhale, potentially leading to CO2 retention rather than elimination. Understanding this helps clarify the role of PEEP in respiratory therapy and its impact on the different aspects of pulmonary function