Diagnostic Mechanisms Flashcards
What does it show on a CXR with COPD?
enlarged lungs( > 6 anterior ribs or >10 posterior ribs), air pockets (bullae), a flattened diaphragm or a hyper lucent lungs
What is the benefit of a CT scan over a CXR in those with emphysema?
It measures the extent of the emphysema within the lungs and also the enlarged arteries in the lungs.
What pulmonary function test is used in patients with COPD?
Spirometry -> measures how much air you can move by taking a deep breath in and out
What other tests can be used?
ABG, which measures how much oxygen and carbon dioxide are present in the lungs
What is seen on a chest x-ray with chronic bronchitis?
broncho vascular markings and cardiomegaly
What is seen on a CRX with emphysema?
flattened diaphragms, small heart and possible bullous changes
What is seen on a CT with chronic bronchitis?
Bronchial wall thickening, enlarged vessels, repeated inflammation -> scarring with broncho vascular irregularity and fibrosis
What is seen on a CT scan with an individual with emphysema?
diagnosed by alveolar septal destruction and airspace enlargement
What is the FVC?
The total volume of air that the patient can exhale in one breath
What is the FEV1?
The amount of air that the patient can exhale in the first second.
What happens to the FEV1 in COPD?
Decreases
What is the typical FEV1/FVC ratio in COPD?
<0.7 after bronchodilator
What is the TLC?
total lung capacity - volume of air contained in the lung after full inhalation
what is the residual volume?
volume of air left in the lung after full exhalation
what is the functional residual capacity?
volume of gas left in the lungs after a tidal breath
What diagnostic mechanism is the best way to calculate lung volumes for COPD?
body plethysmography
What happens to the RV in COPD patients?
Increases - causing trapping of the air in the lung
what happens to the TLC
Increases due to elastic recoil allowing the lungs to stretch to abnormal volumes
What is DLCO?
Measure of how easily carbon monoxide molecules transfer from the alveolar gas to the haemoglobin of the red cells in the pulmonary circulation.
How is DLCO measured?
The patient inhales a single breath containing a minute amount of CO and holds it for 10 seconds, breath is then exhaled and analysed for CO
How is the DLCO calculated?
Concentration of the CO is multiplied by the single breath TLC to calculate the DLCO
When the level of DLCO should the patient undergo oximetry during exercise to determine in oxygen is required?
<55%
