FEV1 lower than 60% predicted is strongly suggestive of severe airway obstruction. Peak flow rate measurement is a simple bedside method to assess the severity of airway obstruction. A red zone indicates less than 50% of the usual or normal peak flow reading signifying a severe airway obstruction.
Status asthmaticus other diagnostic studies
Silicosis other diagnostic studies
Chronic obstructive pulmonary disease other diagnostic studies
Acute bronchitis risk factors
Esophagitis other diagnostic studies
Alpha 1-antitrypsin deficiency other diagnostic studies
Chronic bronchitis echocardiography or ultrasound
Chronic bronchitis risk factors