Adult Critical Care Specialty (ACCS) Practice Exam

What is the deliberate limitation of ventilator support to avoid lung over-distension in ARDS patients called?

1. Tracheal gas insufflation

2. High frequency ventilation

3. Permissive hypercapnia

4. Airway pressure release ventilation

The correct answer is: Airway pressure release ventilation

The practice of deliberately limiting ventilator support to prevent lung over-distension in patients with Acute Respiratory Distress Syndrome (ARDS) is referred to as Airway Pressure Release Ventilation (APRV). APRV is a mode of mechanical ventilation that allows for spontaneous breathing at higher airway pressures while providing limited time at lower pressures. This approach helps to maintain open alveoli (recruitment) and ensures adequate oxygenation without causing barotrauma, which can occur with aggressive positive pressure ventilation. In APRV, the lung is kept in a state of recruitment by providing longer periods of elevated airway pressure, which enhances oxygenation and minimizes the risk of over-distension. This is crucial for ARDS patients who have stiff, non-compliant lungs, as it reduces the risk of ventilator-induced lung injury, a significant concern in this population. While other modes of ventilation like high frequency ventilation or strategies like permissive hypercapnia aim to protect the lungs, they do not specifically focus on the limitation of overall ventilator support in the same way that APRV does. High frequency ventilation emphasizes rapid breaths to minimize tidal volumes, while permissive hypercapnia allows for higher levels of carbon dioxide to achieve lung protective ventilation, yet both maintain a level of traditional