Certified Respiratory Therapist Practice Exam

If a patient's spirometry results show decreased FVC, normal FEV1, and increased FEV1%, what condition is likely present?

1. Obstructive disorder

2. Restrictive disorder

3. Asthma

4. Chronic obstructive pulmonary disease (COPD)

The correct answer is: Restrictive disorder

The scenario described indicates a pattern consistent with a restrictive pulmonary disorder. In this case, a decreased forced vital capacity (FVC) signifies that the total amount of air a patient can forcibly exhale after taking a deep breath is reduced, which is characteristic of restrictive lung conditions. Additionally, normal forced expiratory volume in one second (FEV1) suggests that while the volume of air expelled is reduced overall, the ability to exhale a substantial portion of that volume in the first second is preserved. This situation leads to an increased FEV1%, which is the ratio of FEV1 to FVC. In restrictive disorders, since the FVC is lower but FEV1 remains normal, the ratio can appear increased, reflecting a relatively preserved expiratory capacity in comparison to the reduced lung volume. In contrast, obstructive disorders would typically show a decreased FEV1 alongside a decreased FEV1%, due to significant airflow limitation. Conditions like asthma and COPD, which are examples of obstructive disorders, would not match the spirometry findings presented. Therefore, the spirometry results clearly indicate a restrictive disorder, which aligns with the answer provided.