Lecture 5 - Spirometry Flashcards
What are some examples of obstructive airways diseases?
Asthma, COPD, chronic bronchitis, emphysema, bronchiectasis and cystic fibrosis
What are some examples of restrictive lung diseases?
Interstitial lung disease, musculoskeletal diseases, neuromuscular diseases, obesity and diaphragmatic weakness
What is bronchiectasis?
Mucus secretion, airways become more blocked
What is cystic fibrosis?
Excess production of the mucus
Define restrictive lung diseases
Affect the ability of the lungs to expand and contract
How many different types of interstitial lung diseases are there and what is the most common?
200 types and pulmonary fibrosis is the most common
What is musculoskeletal disease (MS)?
Muscles are affected by neurogenerative diseases and so don’t work as well e.g. the diaphragm
What is diaphragmatic paralysis?
Where the diaphragm gets stuck and can’t open the lungs properly
What is spirometry?
Measures airflow and can be used for athletes and also patients to diagnose asthma
What does spirometry measure?
Measures the responsiveness of airways to medication, measures the severity of airways disease and monitor disease progression
What is used for preparing the spirometer?
Calibration and verification, and infection control
What is calibrating?
When you check the vales are the reading values it is supposed to be reading
What can affect calibration?
BTPS - barometric, temperature and water saturation - the environment affects these things which is why calibration needs to take place
What is used for infection control?
A single use filter and a nose clip
What can stop a spirometer from taking place?
If you had recently had a pneumothorax, recent MI, any aneurysms, eye surgery or thoracic/ abdominal surgery and if you have been experiencing vomiting or nausea
What needs to happen pre-test of the spirometer?
Avoid smoking 24 hours, alcohol 4 hours, vigorous exercise (30 mins), large meal 2 hours and the use of an inhaler 4-12 hours
How is the procedure carried out - position of the patient?
Patient will be seated sitting upright
What does the physiologist need to know about the patient?
Needs to know age, height, birth sex and whether they are a smoker, non smoker or ex smoker
How do you reach resting vital capacity?
3 resting breathes
How is the test taken?
With a nose clip on during tidal breathing, inhale to maximal inspiration and forced expiration (really hard blows)
PEF =?
Peak expiratory flow
FEV1 =
Forced expiratory volume in one second - the max volume of air exhaled in the first second of a forced expiration from a position of full inspiration
FVC =
Forced vital capacity - the max volume of air exhaled with max forced effort from a max inspiration
What is a volume time graph?
Traditionally used in older more simple equipment which provides information on volume and time
What is a flow volume loop?
Found on most modern equipment - had extra information, had a peak flow and extra breathe in but also uses a differential pressure pnenomotachograph
What is Dynamic airway compression?
After the initial blast of air has been exhaled flow is then limited by dynamic airway compression
What determines the flow?
The elastic recoil force of the lung and the resistance of the airways upstream
Is peak flow dependent or independent?
Peak flow is entirely effort dependent
Is FEV1 independent or dependent?
FEV1 is relatively independent of expiratory effort
What is FEV1 reduced by?
By an increase in airway resistance e.g. asthma/COPD or a reduction in elastic recoil of the lung e.g. emphysema
What are the guidelines for spirometry?
Need a minimum of 2 acceptable results and the reproducibility of RVC, FVC and FEV1 need to be within 150ml of the next best value
What is the normal range calculated?
By the predicted value, standard deviations (z scores)
What is the equation for standard residuals (SR)
SR = (observed - predicted)/ SD
What does a positive SR indicate?
A value higher than predicted, a negative value indicates a value lower then predicted
What should the flow volume loop be in a normal person?
Shape should be vertical, smooth descent to baseline, the peak should be sharp
What is the normal for a volume time graph?
The shape should have a vertical rise, the plateau should be reaches within 6-15 seconds
In an obstructive disease what are the FEV1, FVC and FEV1/FVC ratio like?
FEV1 = reduced, FVC = normal, FEV1/FVC is reduced
In a restrictive disease what should the FEV1, FCV and FEV1/FVC ratio be?
FEV1 = reduced, FVC = reduced and FEV1/FVC ratio would be normal
