Term
| a capacity is the combination of 2 or more_________? |
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Definition
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Term
| how is the residual volume calculated? |
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Definition
| the functional reserve capacity minus the expiratory reserve volume |
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Term
| how many tracings should be done for a PFT? how much variation should be between them? |
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Definition
| at least 3 tracings should be done (to get best effort) w/less than a 5% or 100 ml variation between the best 2 of 3 tracings. |
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Term
| what allows pulmonologists to test for residual volume? |
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Definition
| boyles law (VP = VP) and charles's law (V/T = V/T) and solve for V, using a body box with fixed temp and pressure |
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Term
| if functional reserve capacity is increased, what does it represent? |
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Definition
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Term
| when is hyperinflation seen? |
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Definition
| structural changes (emphysema), compensatory overinflation (postop pneumonectomy), deformity of the chest wall, and partial obstruction of the airway as w/asthma |
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Term
| what is forced vital capacity? |
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Definition
| the max amount of air that can be expired after max inspiration *quickly* |
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Term
| what does testing for forced vital capacity r/o? |
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Definition
| restrictive lung disease, (can be caused by abdominal fat, large breasts, sarcoid, fibrosis or scar tissue) |
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Term
| what does testing for forced vital capacity assess? |
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Definition
| forced vital capacity tests expansion of the chest wall and lung to forcefully exhale, which would be reduced in restrictive lung disease, (can be caused by abdominal fat, large breasts, sarcoid, fibrosis or scar tissue) |
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Term
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Definition
| the amount of air that can be forcible exhaled in *1 second* |
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Term
| what does what is FEV1 test for? |
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Definition
| the diameter/patency of the airway, which will be reduced in obstructive lung disease (asthma, COPD, emphysema) |
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Term
| how does the forced expiratory volume of restrictive disease pts compare to pts w/no disease? |
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Definition
| restrictive lung disease people don't have any trouble getting air out, they just can't get it in. therefore, their total intake and exhalation will mimic normal, but it will just be a little smaller |
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Term
| how does the forced expiratory volume of restrictive disease pts compare to pts w/no disease? |
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Definition
| pts w/obstructive disease have no trouble getting air in, they just breathe out much slower - ie over 10 sec as opposed to 3 |
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Term
| how is obstructive airway disease defined?FEV1/FVC |
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Definition
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Term
| what diseases cause obstructive patterns? |
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Definition
| chronic bronchitis, bronchiectasis, aspiration (stomach acid burns lungs), retained secretions, foreign body, asthma, emphysema, neoplasm, enlarged lymph nodes, and peribronchial edema |
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Term
| when comparing various results for obstructive lung disease, what needs to be kept in mind? |
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Definition
| compare numbers, like FVC =/= FVC rather than FEV1/FVC =/= FEV1/FVC, b/c the ratios can throw you off |
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Term
| which lung volumes are decreased in restrictive lung disease? |
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Definition
| all - restrictive is defined by inability to get air into the lungs |
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Term
| what are diseases that can cause restrictive lung disease? |
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Definition
| kyphoscoliosis, polio, myasthenia gravis, guillian-barre, lung fibrosis, sarcoidosis, and fibrocalcific changes to the pleura |
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Term
| what does the diffusion of lung using CO test? |
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Definition
| the rate at which O2/CO2 can diffuse across the alveoloar/capillary membrane - which is decreased in lung fibrosis/excessive lung fluid (restrictive lung disease) |
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Term
| what is the diffusion capacity as tested in the 'diffusion of lung using CO test' related to? what are factors that would affect this? |
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Definition
| diffusion capacity is directly related to surface area and inversely related to thickness. for example - emphysema pts have lost surface area due to hyperinflation and destruction of alveoli and sx pts w/removal of lung will also lose surface area. increased fluid or fibrosis will increase thickness. |
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Term
| how does CO affect pts with O2 diffusion abnormalities? |
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Definition
| normally, RBCs pick up O2 in the lungs and move out in 3/4 of a sec, while in pts w/diffusion abnormalities, the RBCs are oxygenated much slower. both a normal pt and one w/a diffusion abnormality such as emphysema may thus have normal oxygenation on sitting, but the emphysema pt may have much lower O2 diffusion w/a higher CO output (exertion, fever) b/c the blood is then moving quicker through the lungs |
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Term
| what is the difference between midflow and peak flow? |
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Definition
| peak flow (speed of air leaving the lungs at the beginning of a breath) is effort dependent and midflow (speed of air leaving the lungs in the middle of a breath) is effort independent. peak flow is much easier to procure and is used to dx/tx asthma pts |
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Term
| you cannot r/o restriction unless you see ___________? |
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Definition
| residual volume. if the FRC is low (like 50%), then you can dx restrictive disease. remember, the slope is normal looking, everything is just minaturized |
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