Ventilation Flashcards
What is the definition of ventilation
the amount of air entering and leaving the lungs per minute
What is tidal volume
amount of air inspired and expired in routine breathing
Usually about 500 ml
What is total lung volume and how do we calculate it?
usually about 4000 ml
V(t) = V(d) + V(a)
total volume equals dead space volume plus alveolar volume
What is total lung capacity
about 7000 ml (if take really deep breath)
What is vital capacity
the maximum volume of air that can be exhaled after a maximum inspiration; Usually about 6000 ml; Used for testing
What is the residual volume in lungs and can we measure it?
the amount remaining in the lungs after a maximal expiration, Usually about 1500 ml; No
What is functional residual capacity?
the amount remaining after a typical exhalation; Represents the “set point” of the lung and chest; Usually about 2500 ml; Can’t measure this directly but can calculate it; functional residual volumes, as well as, tidal and vital capacity
How do you calculate lung dilution?
10%*Constant amount of helium; (constant amount of helium+amount of air in lungs)
What is normal lung capacity on lung dilution test?
6.7%
What causes higher than normal lung size on dilution test?
COPD, you get huge lungs
How large is the anatomic dead space?
About 150ml
How large is the alveolar gas?
about 3000 ml
How do you calculate alveolar ventilation?
(Tidal volume 500ml - Anatomic Dead Space 150ml)*Breath frequency 15/mn
Which portion of the lung is ventilated better?
Lower portions of the lung are ventilated better than apical regions
What is normal total breath?
500 mL
