What is the primary purpose of the flow proportional assist in PAV?

• A. To provide constant volume regardless of patient effort
• B. To help overcome work of breathing due to resistance
• C. To maintain high respiratory rates
• D. To deliver random tidal volumes

Answer: (B)

The flow proportional assist in Pressure Assist Ventilation (PAV) primarily serves to help overcome the work of breathing due to resistance. In this ventilation mode, the delivered airflow correlates with the patient's efforts, thereby providing assistance in a manner that adjusts to the patient's inspiratory needs. By adapting to the patient's respiratory effort, the ventilator can offer support during inhalation, which directly aids in reducing the work of breathing that a patient must exert, especially in situations where lung mechanics might present increased resistance. This tailored assistance is essential in making it easier for patients to take deeper breaths while minimizing the overall workload required for respiration.

The other options present ideas that do not align with the targeted mechanism of flow proportional assist. Maintaining constant volume or delivering random tidal volumes does not reflect the adaptive nature of this technique. Instead, PAV aims to provide variable assistance based on real-time patient effort, facilitating a more natural breathing pattern. Similarly, high respiratory rates are not a primary focus of flow proportional assist; instead, the emphasis is on enhancing the quality and efficiency of the patient’s own breaths rather than forcing an increase in respiratory rate.