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10 Cards in this Set
- Front
- Back
What is normal airway resistance?
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1-2 cm H2O/L/second of flow
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What causes increased airway resistance?
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tracheal obstruction (tounge), bronchitis, emphysema, asthma
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What is closing volume?
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The volume at which the pressure in the lungs is greater than in the small airways, causing their collapse. [not including RV]
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How is closing volume determined?
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N2 concentration is measured. In stage III, N2 concentration rises as Zone 1 is exhaled, and this marks airway closure
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What is closing capacity?
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Closing volume+residual volume
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What increases closing volume?
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Small airway disease, chronic bronchitis, emphysema, interstitial edema, CHF
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Describe the formula for diffusion/uptake of gas
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Vgas = (Area/Thickness) x D x (P1-P2)
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When may PFTs be warranted in surgical patients?
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Hx of COPD, smoker w/ persistent cough, Hx of wheezing/DOE, Chest wall or spinal abnormalities, morbid obesity, thoracic surgery, Age > 70, upper abd surgery
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What are the effects of smoking?
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Decrease cilliary motility, increase sputum production -> V/Q mismatch, bronchotis ds, airway hyperreacivity, gas trapping
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What are the effects of smoking cessation for 12-24 hours?
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decreases CO level
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