FEV1 in restrictive and obstructive diseases
the forced expiratory volume in one second(FEV1) is the volume of air exhaled by the lungs during the first second of a forced expiration,after maximal inspiration(Kon et al,2008).it is an important tool in lung disease diagnosis and classification.
in normal respiratory health,the maximum forced expiration volume that a person can expire in one second is approximately 80 percent of the total forced vital capacity(FVC).
in obstructive lung diseases,however,the FVC is reduced.furthermore,as a result of the increase in airway resistance,patients with an obstructive disease also have a reduced expiratory flow rate.therefore,a patient with an obstructive disease might have a FVC of only 3 litres,and in the first second of forced expiration exhale only 50 percent (1.5 litres of FEV1 divided by 3 litres of FVC).in obstructive lung diseases the FEV1/FVC ratio decreases.
in restrictive lung diseases,FVC is also reduced.however,owing to the low compliance in restrictive lung diseases,and the high lung recoil,the FEV1/FVC ratio may be normal or even high.in restrictive lung diseases the FEV1/FVC ratio can be normal or higher than normal (figure2).
pulmonary rehabilitation,bronchodilators,and even surgery can be of benefit to patients with emphysema.
FEV1 in restrictive and obstructive diseases
the forced expiratory volume in one second(FEV1) is the volume of air exhaled by the lungs during the first second of a forced expiration,after maximal inspiration(Kon et al,2008).it is an important tool in lung disease diagnosis and classification.
in normal respiratory health,the maximum forced expiration volume that a person can expire in one second is approximately 80 percent of the total forced vital capacity(FVC).
in obstructive lung diseases,however,the FVC is reduced.furthermore,as a result of the increase in airway resistance,patients with an obstructive disease also have a reduced expiratory flow rate.therefore,a patient with an obstructive disease might have a FVC of only 3 litres,and in the first second of forced expiration exhale only 50 percent (1.5 litres of FEV1 divided by 3 litres of FVC).in obstructive lung diseases the FEV1/FVC ratio decreases.
in restrictive lung diseases,FVC is also reduced.however,owing to the low compliance in restrictive lung diseases,and the high lung recoil,the FEV1/FVC ratio may be normal or even high.in restrictive lung diseases the FEV1/FVC ratio can be normal or higher than normal (figure2).
pulmonary rehabilitation,bronchodilators,and even surgery can be of benefit to patients with emphysema.
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