Normal FEV1 / FVC = _____

Normal FEV1 / FVC = 75% (drops with age)

In obstructive lung disease, FEV1 _____, FVC _____, and FEV1 / FVC _____

In obstructive lung disease, FEV1 decreases, FVC decreases or stays constant, and FEV1 / FVC decreases ( FEV1 / FVC \< 0.7 indicates obstructive lung disease)

Why does FEV1 / FVC decrease in obstructive lung disease?

FEV1 / FVC decreases in obstructive lung disease FEV1 decreases because of decreased lung elastic recoil pressure or increased airway resistance FVC may not fall as much because motivated patients may exhale over a longer period This time compensation results in less of a decrease in FVC relative to FEV1, which decreases FEV1 / FVC

In restrictive lung disease, FEV1 ______, FVC ______, and FEV1 / FVC ______

In restrictive lung disease, FEV1 decreases, FVC decreases, and FEV1 / FVC increases

Why does FEV1 / FVC increase in restrictive lung disease?

FEV1 / FVC increases in restrictive lung disease Airflow flow rates plotted at isovolume flow (absolute lung volume) may be higher than normal because elastic recoil pressure is higher and airway resistance is lower than normal Exhalation time may be shorter than normal

SM_174a-175a: Pulmonary Function Flashcards by Nathan Shlobin

Obstructive lung diseases include _____, _____, and _____

Obstructive lung diseases include emphysema, chronic bronchtis, and asthma

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In obstructive lung diseases, the lungs are _____ and may _____ gas

In obstructive lung diseases, the lungs are hyperinflated and may trap gas

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In emphysema, _____ elastic recoil pressure _____ resting lung volume, and _____ elastic recoil pressure and tendency of airways to collapse _____ exhalation

In emphsema, decreased elastic recoil pressure elevates resting lung volume, and decreased elastic recoil pressure along with the tendency of airways to collapse limits exhalation

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In chronic bronchitis and asthma, airflow obstruction occurs because of _____

In chronic bronchitis and asthma, airflow obstruction occurs because of increased airway resistance

(due to some combo of intraluminal mucus, airway wall edema, bronchospasm, and airway wall remodeling)

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An example of a restrictive lung disease is ____

An example of a restrictive lung disease is IPF

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Restrictive lung diseases are characterized by ______

Restrictive lung diseases are characterized by low lung volumes

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In pulmonary fibrosis, lung volume is decreased because of ______

In pulmonary fibrosis, lung volume is decreased because of increased elastic recoil pressure (decreased lung compliance)

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Spirometry measures _____

Spirometry measures expiratory flow rates

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FVC = _____ - _____

FVC = TLC - RV

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FEV₁ is defined as the ____

FEV₁ is defined as the forced expiratory volume in the first second of trying

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Normal FEV₁ / FVC = _____

Normal FEV₁ / FVC = 75%

(drops with age)

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In obstructive lung disease, FEV₁ _____, FVC _____, and FEV₁ / FVC _____

In obstructive lung disease, FEV₁ decreases, FVC decreases or stays constant, and FEV₁ / FVC decreases

( FEV₁ / FVC < 0.7 indicates obstructive lung disease)

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Why does FEV₁ / FVC decrease in obstructive lung disease?

FEV₁ / FVC decreases in obstructive lung disease

FEV₁ decreases because of decreased lung elastic recoil pressure or increased airway resistance
FVC may not fall as much because motivated patients may exhale over a longer period
This time compensation results in less of a decrease in FVC relative to FEV₁, which decreases FEV₁ / FVC

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In restrictive lung disease, FEV₁ ______, FVC ______, and FEV₁ / FVC ______

In restrictive lung disease, FEV₁ decreases, FVC decreases, and FEV₁ / FVC increases

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Why does FEV₁ / FVC increase in restrictive lung disease?

FEV₁ / FVC increases in restrictive lung disease

Airflow flow rates plotted at isovolume flow (absolute lung volume) may be higher than normal because elastic recoil pressure is higher and airway resistance is lower than normal
Exhalation time may be shorter than normal

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Normalization of FEV₁ and FVC following albuterol suggests the patient has _____

Normalization of FEV₁ and FVC following albuterol suggests the patient has asthma

(asthma patients can have normal pulmonary function when asymptomatic)

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In asthma patients, methacholine causes _____ in spirometric measures that _____ with rescue albuterol

In asthma patients, methacholine causes a drop in spirometric measures that improves with rescue albuterol

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Diffusing capacity for carbon monoxide (DLCO) measures the ______

Diffusing capacity for carbon monoxide (DLCO) measures the uptake of inhaled carbon monoxide by hemoglobin

DLCO is increased when _____

DLCO is increased when there is increased hemoglobin in areas of intact ventilation (alveolar hemorrhage, polycythemia)

(breathe in CO but exhale less CO than expected so CO was taken up)

DLCO is decreased when _____

DLCO is decreased when ventilation does not match perfusion (low V/Q) or when there is loss of blood (anemia, R->L shunt) or loss of functional blood vessels (pulmonary embolism, emphysema, interstitial lung disease)

(breathe in CO but exhale more CO so CO was not taken up)

Describe the lung volumes and capacities

FRC: resting lung volume (volume of lung at end of a quiet tidal breath), which is determined by inward elastic recoil of lung and outward elastic recoil of the chest wall
IC = TLC - FRC
TLC: amount of air present within lungs when they are maximally inflated
RV: amount of air present within lungs when they are maximally deflated
ERV = FRC - RV
IRV = IC - TV
TV: amount of air inspired during quiet breath

The width of the flow volume loop is ____

The width of the flow volume loop is FVC

Draw the flow-volume loop for an obstructive lung disease and for a restrictive lung disease

Obstructive lung disease: scooped / concave up
Restrictive lung disease: narrow

(note that curves may face right or left depending on software used)

The normal inspiratory loop on a flow-volume curve is _____

The normal inspiratory loop on a flow-volume curve is symmetric and U-shaped

Flattening of the inspiratory loop on the flow-volume curve suggests _____ or \_\_\_\_\_

Flattening of the inspiratory loop on the flow-volume curve suggests inadequate strength/effort/technique during the forced inhalation maneuver or upper airway obstruction (vocal cord dysfunction, epiglottitis, laryngeal edema, or laryngeal malignancy)

The normal expiratory loop on a flow-volume curve is ______ because \_\_\_\_\_\_\_

The normal expiratory loop on a flow-volume curve is asymmetric because higher expiratory flows are generated at larger lung volumes (this is because elastic recoil pressure is greater and airway resistance is lower via tethering effects of alveoli at higher lung volumes)

Normal expiratory loop on a flow-volume curve is asymmetric because higher expiratory flows are generated at larger lung volumes due to _____ and \_\_\_\_\_

Normal expiratory loop on a flow-volume curve is asymmetric because higher expiratory flows are generated at larger lung volumes due to: * greater elastic recoil pressure * lower airway resistance resulting from the inflated lung pulling the airways open via the tethering effects of alveoli

V·_max = _____ / \_\_\_\_\_

V·max = P_el / R_airway (maximal expiratory airflow = elastic recoil pressure / resistance upstream to the equal pressure point) P_alv is alveolar pressure, P_pl is pleural pressure

Once a certain threshold expiratory effort is generated, greater efforts _____ expiratory flow rates

Once a certain threshold expiratory effort is generated, greater efforts do not increase expiratory flow rates (this is called effort independence) (greater efforts countered by more airway compression)

Expiratory flow rates are greater at _____ lung volume, which is where P_el is _____ and R_airway is \_\_\_\_\_

Expiratory flow rates are greater at larger lung volume, which is where P_el is high and R_airway is low

Describe the volume-time curve for obstructive lung disease and restrictive lung disease

Volume-time curve * Obstructive lung disease: expire less air in first second, can reach same expired volume after much longer time * Restrictive lung disease: limit to the amount of air that can be expired

Expiratory airflow is decreased most by ____ and \_\_\_\_\_

Expiratory airflow is decreased most by low P_el and high R_airway

Emphysema is best characterized by \_\_\_\_\_\_

Emphysema is best characterized by hyperinflation with low DLCO

Isovolume airflow is high in \_\_\_\_\_\_

Isovolume airflow is high in pulmonary fibrosis (restrictive lung disease)

Which test result regarding FEV₁ / FVC suggests asthma?

Low FEV₁ / FVC that normalizes after albuterol

Flattening of the inspiratory loop can be caused by _______ obstruction

Flattening of the inspiratory loop can be caused by variable extra-thoracic (upper) airway obstruction (also by inadequate strength, effort, or technique during forced inhalation maneuver)

V·_max = ____ / \_\_\_\_\_

V·_max = P_el / R where P_el is elastic recoil pressure of lung and R is resistance of airway * Tethering of alveoli keeps airway open * Higher lung volumes increase P_el * At TLC, P_el is high and R is low, which helps generate high flow

In obstructive lung disease, lung volumes are \_\_\_\_\_

In obstructive lung disease, lung volumes are normal or increased

In restrictive lung disease, lung volumes are \_\_\_\_\_

In restrictive lung disease, lung volumes are decreased

In emphysema, the expiratory part of the flow-volume curve is \_\_\_\_\_

In emphysema, the expiratory part of the flow-volume curve is scooped out / concave (obstructive lung disease) * Damage to alveoli causes loss of elastic recoil * P_el decreases so peak flow decreases and flows are decreased at any given volume * Airways collapse due to loss of tethering of elastic structure

In chronic bronchitis, the expiratory part of the flow-volume curve is \_\_\_\_\_

In chronic bronchitis, the expiratory part of the flow-volume curve is scooped out / concave (obstructive lung disease) * Larger airways are narrowed so R increases

In asthma, the expiratory part of the flow-volume curve is \_\_\_\_\_\_

In asthma, the expiratory part of the flow-volume curve is scooped out / concave * Airways narrowed so R increases so V·_max decreases (flow decreases)

In obstructive lung disease, FEV₁ / FVC \_\_\_\_\_\_

In obstructive lung disease, FEV₁ / FVC decreases (FEV₁ and FVC decrease but the ratio decreases due to time compensation) (\< 0.7 is obstructive lung disease)

In restrictive lung disease, FEV₁ / FVC \_\_\_\_\_\_

In restrictive lung disease, FEV1 / FVC increases * Isovolume flow higher than health * Width on flow-volume curve is narrower: FVC decreases