L13: Principles Of Spirometry Flashcards
What is spirometry
Quantitative diagnostic test
What are the 2 ways of directly measuring
Piston spirometer
Water bell spirometer
What are the ways of indirect measurement
Peak expiratory flow
Pneumotachograph
What are the 3 variable that we can measure
Flow
Volume
Time
What tool measures the flow vs time
Peak expiratory flowmeter
What can peak flow be used for
Diurnal asthma to plot it into a diary
What is the peak flow biased to
The upper airways
What is peak flow dependent upon
Airway diameter
Tissue recoil
Effort
Which tool measures volume vs time
Spirometry
What is residual volume
The volume of air left in the lungs after a forced expiration
Which method measures residual volume
Helium dilution
What does a restrictive lung disease show with volume
Reduced lung volume
What does an obstructive lung disease do to airway resistance
Increase airway resistance
Examples of restrictive lung disease
Fibrosis
Pulmonary oedema
What would a restrictive lung disease show on a spirometry
Low vital capacity
Normal FEV1
What are the examples of obstructive lung disease
Asthma
Bronchitis
What does an obstructive lung disease show on a spirometry
Normal vital capacity
Low FEV1
What is FEV1
Forced expiration volume in 1st second (rate)
What is a normal FEV1
Greater than 80%
In an obstructive lung disease what would be the FEV1
Less than 80%
What would an obstructive lung disease show on a peak expiratory flow rate graph show
Reduced peak flow and descending limb
What would a restrictive lung disease show on a peak expiratory flow rate graph show
Reduced peak flow and area under the curve
Name a condition which is a restrictive and obstructive lung disease
COPD
How can COPD be classed as restrictive
Early stage of COPD has loss of alveolar elastic structure and therefore loss of diffusive area
How can COPD be classes as an obstructive lung disease
Inflammation in small airways gives increases resistance
