What does PEF stand for and what is its primary use?

PEF stands for Peak Expiratory Flow, and its primary use is to measure airflow obstruction in the lungs. This measurement is particularly important for patients with respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD). By assessing how quickly a person can exhale air, healthcare providers can determine the severity of airway obstruction and monitor changes over time. This information can help guide treatment decisions and manage the patient's condition more effectively.

The other options focus on different aspects of respiratory assessment that do not relate directly to PEF. Assessing lung compliance involves measuring the lung's ability to expand, which is a different function than what PEF measures. Determining tidal volume refers to the amount of air inhaled and exhaled in a normal breath, which is unrelated to the peak flow measurements. Evaluating oxygen saturation involves measuring the amount of oxygen in the blood, which is also distinct from what PEF provides. Thus, the correct answer highlights the specific and critical role of PEF in the context of airway obstruction.