What term describes the greatest rate of airflow achievable during forced expiration when lungs are fully inflated?

The term that describes the greatest rate of airflow achievable during forced expiration when the lungs are fully inflated is Peak Expiratory Flow Rate (PEFR). PEFR is a measure of how quickly air can be expelled from the lungs when a person forcefully exhales after taking a deep breath. This measurement is particularly important in assessing and monitoring conditions such as asthma, where airflow obstruction can significantly affect breathing.

In contrast, Forced Vital Capacity (FVC) refers to the total volume of air that can be forcibly exhaled after taking the deepest breath possible. It does not represent the maximum flow rate but rather the total amount of air exhaled.

Residual Volume (RV) is the amount of air remaining in the lungs after a forced exhalation and does not pertain to airflow rates during forced expiration.

Inspiratory Capacity (IC) is the maximum volume of air that can be inhaled after expiration and, again, does not relate to the rate of airflow during expiration.

Thus, PEFR is specifically focused on the rate of flow during expiration, making it the correct term in this context.