What causes the prolonged expiratory phase during an asthma attack?

The prolonged expiratory phase during an asthma attack is primarily caused by bronchiole constriction. In asthma, the airways become inflamed and narrowed due to the contraction of smooth muscle around the bronchioles, leading to increased resistance during exhalation. This constriction restricts airflow and makes it more difficult for air to leave the lungs, resulting in a longer expiratory phase.

As the airflow is impeded, air becomes trapped in the lungs, causing difficulty in fully expelling breath. This is characteristic of asthma and highlights the impact of bronchial muscle tightening on respiratory dynamics. Understanding this mechanism is crucial for recognizing the physiological changes that occur during an asthma attack and the challenges the body faces in maintaining adequate ventilation.