FEV1
volume of air expelled in the first second of a forced expiration
can determine the effects of bronchodilators on the airways
FVC (forced vital capacity)
total volume of air exhaled with maximum effort
FEV1/FVC
The ratio of the forced expiratory volume in the first one second to the forced vital capacity of the lungs
grade 1 MRC dyspnoea scale
not troubled except on strenuous exercise
grade 2 MRC dyspnoea scale
short of breath when hurrying on the flat or walking up a slight hill
grade 3 MRC dyspnoea scale
walks slower than most on the flat, stops after about a mile, or stops after 15min at own pace
grade 4 dyspnoea scale
stops for breath after walking 100 yards or a few min of the level
grade 5 MRC dyspnoea scale
too breathless to leave the house, or when undressing
spirometry is used in people with asthma or COPD to…
- diagnose airflow obstruction in patients with respiratory symptoms
- monitor disease progression, rehabilitation and treatment gains
SVC (slow vital capacity)
maximal amount of air exhaled steadily from fill inspiration to maximal expiration
not time-dependent
can help differentiate between restrictive and obstructive pulmonary disease
FEV1/FVC ratio
spirometry values for obstructive disorder
FEV1 reduced <80% predicted
FEV1/FVC reduced <0.7
spirometry values for restrictive disorder
FEV1 reduced <80%
FVC reduced <80%
FEV1/FVC normal >0.7
PEFR (peak expiratory flow rate)
volume of air forcefully expelled from the lungs in one quick inhalation
used for asthma only but spirometry preferred for diagnosis
