Memory Joggers: Spirometry Interpretation

Obstructive Pattern
FVC reduced
FEV, reducedA
%FEV1 reduced (this especially)

Diagnosis: COPD, asthma, bronchitis, Cystic fibrosis, and small airway disease


Restrictive Pattern
FVC reduced
FEV1 normal or slightly reduced
%FEV1 normal or increased

Diagnosis: thoracic abnormalities, interstitial lung disease, space occupying lesions, and pleural effusions


Think about mixed Obstructive and Restrictive when:
FVC reduced
FEV1 reduced
%FEV1 reduced, but higher than FVC


Post Bronchodilator
FEV1 Increase of 12% or 200ml indicates significant improvement.
If less than 8% change or a change of less than 150ml the patient probably has not responded


FVC
80-120% normal
70-79% mild reduction
50-69% moderate reduction
<50% severe reduction


FEV1
>75% normal
60-75% mild obstruction
50-59% moderate obstruction
<49% severe obstruction