Neonatal Nurse Practitioner Practice Exam

What mechanism is primarily responsible for breath delivery in HFJV?

1. Diaphragmatic contraction

2. Direct pulse of pressurized gas

3. Negative pressure ventilation

4. Active lung expansion

The correct answer is: Direct pulse of pressurized gas

In High-Frequency Jet Ventilation (HFJV), the primary mechanism for breath delivery is the direct pulse of pressurized gas. In this mode of ventilation, small jets of gas are delivered into the airway at a rapid rate, creating brief high-pressure pulses that effectively inflate the lungs. This technique utilizes rapid bursts of pressure to generate tidal volumes sufficient to maintain adequate ventilation. The use of pressurized gas allows for very quick inflation and deflation cycles, which is key to the physiological goals of HFJV, particularly in providing oxygenation while minimizing the risk of lung injury, as it reduces the need for larger tidal volumes. This method is particularly beneficial in certain clinical situations, such as in patients with compromised pulmonary mechanics or in scenarios where traditional mechanical ventilation might cause further lung damage. The advantages of this technique include improved oxygenation and reduced intrathoracic pressure disturbances, making it preferable in specific neonatal settings. Other mechanisms, such as diaphragmatic contraction, negative pressure ventilation, and active lung expansion, play roles in different forms of ventilation but are not the primary means of breath delivery in the context of HFJV.