Which value represents an increase in airway resistance and is measured during a forced expiratory effort?

Which value represents an increase in airway resistance and is measured during a forced expiratory effort?

• A. FVC
• B. RV
• C. FEV1
• D. TLC

Answer: (C)

An increase in airway resistance is primarily assessed through the measurement of FEV1, which stands for Forced Expiratory Volume in the first second of a forced expiratory maneuver. In conditions characterized by increased airway resistance, such as asthma or chronic obstructive pulmonary disease (COPD), the ability to exhale forcefully and rapidly is diminished, resulting in a lower FEV1 value. This occurs because the narrowed airways resist the flow of air, leading to a reduced volume of air being expelled in the first second of a forced expiration. In contrast, FVC (Forced Vital Capacity) measures the total volume of air that can be forcibly exhaled after taking a deep breath and does not directly indicate airway resistance. RV (Residual Volume) measures the volume of air remaining in the lungs after a full exhalation, and TLC (Total Lung Capacity) is the total volume of air in the lungs at maximum inflation. While these last two values can provide insight into lung mechanics and capacity, they do not specifically reflect changes in airway resistance during a forced expiratory effort. Thus, the correct choice, which showcases the impact of increased resistance in the airways, is FEV1.

An increase in airway resistance is primarily assessed through the measurement of FEV1, which stands for Forced Expiratory Volume in the first second of a forced expiratory maneuver. In conditions characterized by increased airway resistance, such as asthma or chronic obstructive pulmonary disease (COPD), the ability to exhale forcefully and rapidly is diminished, resulting in a lower FEV1 value. This occurs because the narrowed airways resist the flow of air, leading to a reduced volume of air being expelled in the first second of a forced expiration.

In contrast, FVC (Forced Vital Capacity) measures the total volume of air that can be forcibly exhaled after taking a deep breath and does not directly indicate airway resistance. RV (Residual Volume) measures the volume of air remaining in the lungs after a full exhalation, and TLC (Total Lung Capacity) is the total volume of air in the lungs at maximum inflation. While these last two values can provide insight into lung mechanics and capacity, they do not specifically reflect changes in airway resistance during a forced expiratory effort. Thus, the correct choice, which showcases the impact of increased resistance in the airways, is FEV1.