Which condition is characterized by an obstructive ventilatory defect?

An obstructive ventilatory defect is characterized by difficulty in expelling air from the lungs, leading to a decreased airflow rate. In conditions such as severe asthma and bronchitis, this defect is evident.

Severe asthma causes episodes of airway constriction and inflammation, leading to increased airway resistance. During an asthma attack, the air passages narrow, which makes it challenging for air to exit the lungs efficiently, resulting in symptoms like wheezing, shortness of breath, and chest tightness.

Bronchitis, particularly chronic bronchitis, involves inflammation and thickening of the bronchial tubes. The production of excess mucus can obstruct the airflow, further contributing to difficulties in breathing and reduced airflow capacity during expiration.

Both severe asthma and bronchitis exhibit similar obstructive patterns in pulmonary function tests, such as a reduced FEV1/FVC ratio, which is characteristic of obstructive lung diseases. Therefore, choosing the option that includes both severe asthma and bronchitis reflects the understanding that both conditions lead to an obstructive ventilatory defect.