Forced Expiratory Volume in 1 second (FEV₁) is a key spirometric measure used to assess lung function.
Clinical significance
- Diagnosis and staging: FEV₁ is commonly used in the diagnosis and staging of chronic obstructive pulmonary disease (COPD)
- Predictive value: Reduced FEV₁ is associated with an increased risk of premature death from all causes, including COPD, lung cancer, coronary artery disease, and stroke
- Lung function interpretation: FEV₁ is used in conjunction with other measures, such as forced vital capacity (FVC), to interpret lung function and detect airflow obstruction
- Impact of comorbidities: The rate of decline in FEV₁ can be influenced by comorbid respiratory diseases, such as asthma and COPD
Limitations
- Crude measure: FEV₁ is considered a crude measure and may be insensitive to changes over shorter periods of time
- Influence of birth weight: Lung function, as measured by FEV₁, can be reduced in infants with low birth weight for gestation, independent of somatic growth during infancy
Alternative measures
- FEV₆: Forced expiratory volume in six seconds (FEV₆) has been suggested as a substitute for FVC in certain contexts, such as workplace settings, to reduce test time and frustration . However, substituting FEV₆ for FVC may reduce the sensitivity of spirometry to detect airflow obstruction, especially in older individuals and those with lesser obstruction
In conclusion, FEV₁ is a vital measure in assessing lung function, with significant clinical utility in diagnosing and staging respiratory diseases, predicting mortality, and interpreting lung function. However, it has limitations and may be complemented by other measures in certain contexts.