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Flashcards in 7. Ventilation Deck (13):

Minute ventilation (Ve)

total volume of gas that entering lungs per minute
Ve = tidal volume x respiratory rate


Alveolar ventilation (Va)

Volume of gas per uniy yime that REACHES ALVEOLI
Va= (tidal volume-physiological dead space) x repisratory rate


What is minute ventilation (VE)? How do you calculate it?

The total volume of gas entering the lungs each minute; VE = VT × respiratory rate


A patient with a tidal volume of 400 mL is breathing 20 times per minute. What is his minute ventilation?

8000 mL/min, as minute ventilation (VE) = 400 mL × 20 breaths/min


What is alveolar ventilation (VA)? How do you calculate it?

The volume of gas per unit time that reaches the alveoli; VA = (VT - VD) × respiratory rate


A patient is breathing naturally. Describe the natural tendency of movement of the lung and chest wall.

The lungs tend to collapse inward, and chest wall springs outward


At what point in the respiratory cycle is the inward pull of the lung equal to the outward pull of the chest wall?

At functional residual capacity


At the point of functional residual capacity, what is the value of the air pressure within the lungs?

At FRC, the pressure within the lungs is equal to atmospheric pressure


A patient takes in a deep breath. What determines the combined volume of the chest wall and lungs?

Elastic properties of both


In terms of lung pressures, explain how a pneumothorax is prevented.

At FRC, lung pressures are atmospheric, and opposing forces of the lung and chest wall create negative pressure in the intrapleural space


When is pulmonary vascular resistance at a minimum?

At functional residual capacity


A 43-y/o woman has pulmonary fibrosis. How does this affect her lung compliance? Other conditions that would affect compliance similarly?

Lung compliance decreases with pulmonary fibrosis, and in pulmonary edema and pneumonia


Lung compliance ____ (increases/decreases) in a patient with emphysema, and with natural aging.