Rehab Lectures Flashcards
Define spirometry and what it measures
Measurement of the individual’s ability to move air in and out of the lungs. It measures volume and flow rate
What does a diagnosis of a lung disease require?
Positive spirometry findings, a history of respiratory risk factors and/or respiratory symptoms
What is FEV1?
The volume of air expired forcefully during the first second - forced expiratory volume in one second
What is FVC?
The total volume of air exhaled forcefully after a full inspiration - forced vital capacity
How to calculate the forced expiratory volume and forced vital capacity ratio?
FEV1/FVC
Describe the volume flow loop for different diseases
- Obstructive = slow down really quickly = a concave appearance on expiratory part
- Restrictive = shape looks the same but just smaller
See lecture notes for diagrams :)
How much air should come out in the first second of forced expiration?
75%-80%
What are the predictive values of spirometry?
Sex, height, age (sometimes ethnicity)
Obstructive lung disease summary
Obstruction to airflow on expiration = air gets trapped in lungs = hyperinflation of lungs = flattening of diaphragm = SOB develops due to inability to increase tidal volume
Restrictive lung disease summary
Increased stiffness of lungs = restricted inspiratory volumes = total lung capacity is reduced = SOB develops due to an inability to increase tidal volume
What would you expect in spirometry if someone had an obstructive lung disease?
- FEV1 is reduced (brakes come on a bit soon) due to air being stuck in expiration
- FVC remains relatively unchanged
- FEV1/FVC ratio decreases (>70% = obstructive lung disease)
What does the new COPD scale display?
Severity of symptoms, hospital admissions, frequency of exacerbations
What would you expect in spirometry if someone had a restrictive lung disease?
- Total lung capacity and FVC are reduced as they aren’t able to inspire enough - so no problem with obstruction/airflow, they just can’t get a lot of air in
- FEV1/FVC ratio is the same or increased
What is peak expiratory flow rate and what are the normative/predictive values?
PEFR = the maximum speed of expiration. This is used to monitor pulmonary function over time for someone with a known lung pathology e.g. asthma
Values = age, sex, height and ethnicity
What determines the black and white on an X-ray?
X-ray absorption - if the X-ray pass through the body easily = black
What are the cobweb-like structures on a normal X-ray?
The pulmonary blood vessels which you can see right to the edge of the lungs - blood is fluid, hence, why it looks whiter on the X-ray
What is the common view for a chest X-ray and how should it be done?
Postero-anterior view
It should be completed with a breath in and hold, patient is standing, arms abducted to rotate scapulae away and X-ray is about 1.8 metres away from the patient
What are some things that should be seen on a normal chest X-ray (posteroanterior view)?
Air in trachea (shown by trachea being slightly darker), heart should take up ~50% of diameter of the chest, cobweb-like pulmonary vessels, dome shapes of diaphragm, right diaphragm is higher (due to liver), clavicles are the same distance away from the spine, can see 8-9 ANTERIOR ribs, trachea is in midline (in line with spinous processes)
Anterior view X-rays
- Used when patient is unable to stand i.e. unconscious or too unwell
- X-ray is ~40 inches away from patient = hazy/blurry X-ray
- Heart will appear bigger as X-ray machine is closer
How to tell if the X-ray is overexposed?
You can see the intervertebral discs clearly and the image appears really dark
How to tell if the X-ray is underexposed?
You cant see individual spinous processes and the X-ray looks ‘bright’
What would you expect in an X-ray for a patient with COPD?
Flattened diaphragm, wide spacing between ribs , blunted costophrenic angles, may appear blacker due to increased air in the lungs
What would you expect in an X-ray for a patient with consolidation (infection)?
White patchy appearance due to inflammation and secretions, no clear outline of the heart (known as the Silhouette sign)
What would you expect in an X-ray for a patient with heart failure?
Enlarged heart (cardiomegaly) i.e. above 50% of the chest diameter