Spirometry Flashcards
Normal FEV/FVC
Greater than 0.7
A measure of airflow obstruction
FVC
Forced vital capacity
Vital= Lung volume - residual volume
Difference between obstructive and restrictive patterns?
Obstructive: Increase in residual volume due to loss of elastic recoil
Restrictive: Less elastic due to fibrosis. Like a used elastic band
2 common obstructive lung disease
Asthma
COPD
Bronchiestasis
CF
3 components of asthma pathophysiology?
Airway narrowing / obstruction
Airway hyper-responsivemess
Airway inflammation
COPD characteristics?
Persistent airflow limitation (then progressive)
+ enhanced chronic inflammatory response in the airways and the lung to noxious particles
Cause of COPD
Smoking AATD (alpha 1 antitrypsin deficiency)
Pathophysiology of COPD?
Inflammation + fibrosis of the bronchial wall –> Bronchiectasis
Hypertrophy of the submucosal glands and hypersecretion of mucous
Loss of elastic and parenchymal lung fibres -> Emphysema
Clinical presentation of COPD
- Insidious onset
- Usually 50s or 60s
- Chronic cough
- Sputum production ( typically worse in the morning)
- Increasing (over time) shortness of breath
- Diminishing exercise tolerance (specifics)
- History of exposure to risk factors
Residual volume =
((C1/C2)-1) * volume of the spirometer
C1: Conc of He in spirometer before inhalation
C2: He concentration after equilibrium is achieved by breathing
What is FRC?
Functional residual capacity
How is FRC measured
((C1/C2)-1) * volume of the spirometer
C1: Conc of He in spirometer before inhalation
C2: He concentration after equilibrium is achieved by breathing
BUT before inhaling the air-helium mixture, the subject is asked to breathe out normally
