What is the interpretation of a spirometry result showing a Forced Vital Capacity (FVC) of 58%, a Forced Expiratory Volume in one second to Forced Vital Capacity ratio (FEV1/FVC) of 80%, and a Forced Expiratory Volume in one second (FEV1) of 76%?

From the Guidelines

The spirometry results indicate a restrictive lung pattern with a significantly reduced FVC of 58% of predicted, a normal FEV1/FVC ratio of 80%, and a moderately reduced FEV1 of 76% of predicted, suggesting a restrictive lung disorder rather than obstructive disease. This interpretation is based on the most recent and highest quality study available, which emphasizes the importance of interpreting spirometry results in the context of restrictive lung diseases 1. The preserved FEV1/FVC ratio is a key distinguishing feature from obstructive disorders like asthma or COPD, which typically show a reduced ratio.

Some key points to consider in the interpretation of these results include:

• The FVC is significantly reduced, indicating a reduction in total lung volume, which is consistent with a restrictive lung disorder.
• The FEV1/FVC ratio is normal, which suggests that the airflow is preserved, and the reduction in FVC is not due to an obstructive process.
• The FEV1 is moderately reduced, which is consistent with a restrictive lung disorder.

The diagnosis and management of restrictive lung disorders require a comprehensive approach, including:

• Complete pulmonary function tests with lung volumes and diffusion capacity to further characterize the lung function.
• Chest imaging to evaluate for any underlying lung disease or other conditions that may be contributing to the restrictive pattern.
• Clinical correlation with symptoms and medical history to determine the underlying cause of the restriction and guide treatment.

It is essential to note that the interpretation of spirometry results should be done in the context of the individual patient's clinical presentation and medical history, and that a comprehensive evaluation is necessary to determine the underlying cause of the restrictive lung pattern 1. Additionally, the use of arm span as an alternative to height in patients with osteogenesis imperfecta or other conditions that affect stature may be necessary to accurately interpret spirometry results 1.

From the Research

Spirometer Interpretation

The given spirometer values are:

• FVC (Forced Vital Capacity): 58
• FEV1/FVC (Forced Expiratory Volume in 1 second to Forced Vital Capacity ratio): 80
• FEV1 (Forced Expiratory Volume in 1 second): 76

Pattern Identification

Based on the values, the FEV1/FVC ratio is 80, which is within the normal range (typically > 70-80%) [ 2 ]. However, the FVC value is 58, which is lower than the normal range. This suggests a restrictive pattern, as the total lung volume is reduced.

Clinical Implications

Restrictive lung diseases are characterized by a reduction in total lung volume, and the given spirometer values support this diagnosis [ 2 ]. The patient may have an underlying condition such as interstitial lung disease, obesity, or neuromuscular disorders, which can cause a restrictive pattern on spirometry. Further evaluation and management may be necessary to determine the underlying cause and develop an appropriate treatment plan.