Diagnosing Asthma Spirometry Test lung function when diagnosing asthma
Diagnosing Asthma: Spirometry Test lung function when diagnosing asthma
Spirometric Indicies o FEV,- Forced expiratory volume in one second The volume of air expired in the first second of the blow FVC-Forced vita/ capacity The total volume of air that can be forcibly exhaled in one breath FEV,/FVC ratio: The fraction of air exhaled in the first second relative to the total volume exhaled
Spirometric Indicies • FEV1 - Forced expiratory volume in one second: The volume of air expired in the first second of the blow • FVC - Forced vital capacity: The total volume of air that can be forcibly exhaled in one breath • FEV1 /FVC ratio: The fraction of air exhaled in the first second relative to the total volume exhaled
SPIROMETRY OBSTRUCTIVE DISEASE
SPIROMETRY OBSTRUCTIVE DISEASE
obstructive disease Decrease in expiratory flow rates 5 Normal 4 s FEV,=18L 2 FVC =3.2L obstructive FEV,/FVC=0.56 V 123456 Time seconds
Obstructive Disease Decrease in expiratory flow rates Volume, liters Time, seconds 5 4 3 2 1 1 2 3 4 5 6 FEV1 = 1.8L FVC = 3.2L FEV1 /FVC = 0.56 ↓ Normal Obstructive
Bronchodilator Reversibility Testing Provides the best achievable FEV1 (and Fvc) Helps to differentiate coPd from asthma
Bronchodilator Reversibility Testing • Provides the best achievable FEV1 (and FVC) • Helps to differentiate COPD from asthma