Term
| why is FVC measured as expiratory flow rather than inspiratory flow? |
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Definition
| expiratory flow is more reproducible (effort-independent) at lower lung volumes; EPP location does not depend on effort and this accounts for the reproducibility |
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Term
| FVC test is valid only if... |
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Definition
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Term
| range for normal spirometry values |
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Definition
|
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Term
|
Definition
| >80% for healthy young adults; >75% for elderly |
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Term
| PV loop shows flattened inspiratory limb; dx? |
|
Definition
| upper airway obstruction, specifically extrathoracic |
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Term
| PV loops shows "scooped tail" at lower lung volumes; graph is shifted to the left; dx? |
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Definition
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Term
| PV loop shows slightly reduced PEF and is shifted to the right; dx? |
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Definition
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Term
| requirements for a positive bronchodilator test |
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Definition
| >12% or >200ml increase in FEV1 or FVC |
|
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Term
| requirements for a positive bronchoconstrictor test |
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Definition
| >20% decrease in FEV1 at 0.8mg/ml histamine or methacholine |
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Term
| positive bronchodilator test; dx? |
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Definition
|
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Term
| how is lung volume measured? |
|
Definition
| inert gas dilution or body plethysmography |
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Term
| what information does DLCO give about respiratory mechanics? |
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Definition
| surface area for gas exchange, inhalation of CO, diffusion of CO, binding of CO to Hb |
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Term
| why does DLCO increase in exercise? |
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Definition
| increased recruitment of capillaries, increased tidal volume |
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Term
| would you expect DLCO to be bigger in Matt or Bev? |
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Definition
| Matt--DLCO increases with lung size (body size) |
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Term
| how does air trapping and hyperinflation change PFTs in obstructive lung disease? |
|
Definition
| air trapping increases RV; hyperinflation increases FRC and TLC |
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Term
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Definition
| caused by increased compliance -> higher lung volumes at rest |
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Term
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Definition
| caused by inability to fully expire due to obstructed airways; increases RV and forces tidal breathing to occur at a lower compliance, higher workload point |
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Term
| how would morbid obesity affect PFTs? |
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Definition
| restrictive "lung" disease -> decrease TLC, FRC; increase RV |
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Term
| what would spirometry show in a pt with sarcoidosis/asbestosis/silicosis with PMF/cardiogenic pulmonary edema |
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Definition
| mixed lung disease = decreased TLC, decreased FEV1/FVC |
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Term
| what is a cause of hypercapnia that does not require pulmonary therapy? |
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Definition
|
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Term
|
Definition
| atelectasis, pulmonary edema, respiratory distress, hypoxemia, functional shunt; possible PDA |
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Term
|
Definition
| noncardiogenic pulmonary edema, loss of surfactant, decreased compliance |
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