Lung Volumes Flashcards
(24 cards)
Make sure you know all the lung volumes/capacities on the spirometry graph, Can you draw the graph right now and label them all?
Yes? DO IT! ;-)
What’s the Tidal Volume (TV)?
the volume of air moved in and out of the respiratory tract (breathed) during each ventilatory cycle. Normal adult 500cc
What’s the Inspiratory Reserve Volume (IRV)?
the additional volume of air that can be forcibly inhaled following a normal inspiration. It can be accessed simply by inspiring maximally, to the Maximal Inspiratory Level. Normal adult 3000cc
What’s the Expiratory Reserve Volume (ERV)?
the additional volume of air that can be forcibly exhaled following a normal expiration. It can be accessed simply by expiring maximally to the Maximal Expiratory Level. Normal adult 1100cc
What’s Vital Capacity (VC)?
the maximal volume of air that can be forcibly exhaled after a Maximal Inspiration. VC = TV + IRV + ERV
What’s Residual Volume (RV)?
that volume of air remaining in the lungs after a Maximal Expiration. It cannot be expired no matter how vigorous or long the effort. RV = FRC - ERV. Normal adult 1200cc
What’s Functional Residual Capacity (FRC) ?
the volume of air remaining in the lungs at the end of a normal expiration. FRC = RV + ERV. Normal adult 2300cc
What’s Total Lung Capacity (TLC)?
the volume of air in the lungs at the end of a Maximal Inspiration. TLC = FRC + TV + IRV = VC + RV. Normal adult 5800cc
Maximal Breathing Capacity (also called “Maximal Voluntary Ventilation”) is ______
the maximum volume of air that can be exhaled by voluntary effort in a 15 second interval. This volume is multiplied by 4 and expressed as liters per minute.
Maximal Voluntary Ventilation is to have pt breathe as deeply and as quickly as they can to test pt’s pulmonary motor ability. Y/N?
Y
What’s closing capacity?
The volume in the lungs where airways and alveoli start to collapse. It’s usually in between FRC and RV on the graph
What affects closing capacity:
Age, Smoking History, Intrinsic Lung Disease, Body Position
Small airways lack cartilage and rely on radial traction to maintain patency, Volume at which small airways close in the base of the lung is closing capacity, Leads to shunting of blood, Increased work of breathing. Y/N?
Y
What affects FRC?
Body Habitus , Sex, Posture, Age, Lung Disease, Diaphragmatic Tone
FRC 10% less in females than males. Y/N?
Y
trendelenburg decreases FRC the most; pt in sitting position has less FRC than pt standing up. Y/N?
Y and Y
Anesthesia ______(decreases/increases?) FRC, ______(decreases/increases?) Total lung capacity, ______(decreases/increases?) airway resistance
Decreases, Decreases, Increases
Based on Poiseuille’s Law, which factor increases airway resistance the most?
Airway diameter
Where do you see the highest airway resistance?
Bronchus. 80% airway resistance come from bronchi.
Why do pts who only breathes 3 VC of 100% O2 desat quicker than pts who breathe normal tidal volume for 3min?
3min helps saturate the venous blood and tissue O2 whereas 3VC only saturates the arterial blood.
When closing capacity is larger than FRC, it can lead to atelectasis, hypoxemia, and shunting. Y/N?
Y
Most of the ventilation goes to the middle part of the lung. Y/N?
Y. apex area alveoli are almost all the way expanded, they can’t take much more volume; alveoli at the bottom part of the lung are small and has more surface tension, they tend to collapse
COPD pt has less elastic/fibrous tissue that attaches alveoli to other lung components; they don’t get the radial traction, thus semi-collapsed lung to start with, and obstructive for pt to get air outward. Y/N?
Y
Airway resistance increases at lower lung volume due to less radial traction and more surface tension. Y/N?
Y
