3-13 Lecture Flashcards
Nitrogen Wash Out Test Continued, FVC, Closing Capacity
The Nitrogen washout test is easy to do but is dependent on what?
how even the ventilation is happening in the lungs in general
Sick lungs have a problem with even distribution of ________.
ventilation
Flow Volume Loops
FVL show both inspiration and expiration, but we are most interested in ________ curve.
Maximal Peak Expiratory Force
We will see theses or derivatives of this pulmonary function test in clinical because they are very common according to Dr. Schmidt
Flow Volume Loop
Flow Volume Loop
What is maximal peak expiratory flow?
What is FVC?
PEF measures the speed or flow rate of air during the initial phase of a forced expiration. It gives us an idea of how fast air can be expelled from the lungs but doesn’t tell us about the total volume of air exhaled.
FVC measures the total volume of air that can be forcibly exhaled after taking a deep breath, regardless of the speed of exhalation.
Flow Volume Loop
T/F: These loops are useful and we are typically looking at the Forced Vital Capacity
True
Flow Volume Loops
Peak expiratory flow rate will be ________ if we have a lung issue
lower
Flow Volume Loops
Restrictive diseases have ________ lung volumes and there is ________ elastic tissue
low; excess
Flow Volume Loops
Lung volume is related to what?
Airway resistance
A lung that is emptier than normal will make the small airways a lot more ________. Because the small airways are more ________, it’s easier to ________ them which limits the ________.
narrow; narrow; compress; expiratory flow rate
T/F: For obstructive diseases, if we force an expiration using a lot of effort, this effort will be useful early on to get some air out of the lung, and it will come out at a normal
pace.
F
the air it will not come out at a normal
pace; it will be much slower
To get air out of the lungs we rely on 2 things:
- A change in pleural pressure
- Recoil of the lung to help push air out of the lungs
How do we know if a breath is passive or forced?
If PIP is negative.
If it’s negative, this is NOT a forced breath
What force is holding the airways open?
- 8 mmHg
What areas of the respiratory tract have cartilage?
The upper respiratory tract and conducting zone
The small airways ability to stay open is entirely dependent on what 2 things?
the pressure inside the small airway and the pressure in the environment (the pleural pressure)
What are some things that can predispose airways to collapse?
- Narrow airways: increase likelihood of collapse because the walls are much closer together
- Low lung volumes
- Asthma
More elastic tissue (springs) = ________ recoil
more
T/F: Less elastic tissue = less recoil, resulting in a more compliant lung.
T
This is what happens with emphysema patients
The springy tissue of the alveoli also provides ________ on the small airways, helping to keep them open.
traction
In COPD, especially emphysema, there is a loss of ________ and ________, leading to difficulty in expelling air
from the lungs.
elastic recoil; airway traction
Does having more “springs” or elastic tissue around the airway make it easier or harder to collapse?
Harder to collapse (assuming the airway diameter is
normal)
A thicker wall would be harder to compress
The number one factor in getting air out of the lungs is having sufficient ________ in the lung tissue.Without this, it becomes hard to fully expel air and replace it with fresh air.
elastic recoil
What are the 3 types of obstructions that can be seen on a Flow Volume Loop?
- Fixed Obstruction (Intra or Extrathoracic)
- Variable Intrathoracic Obstruction
- Variable Extrathoracic Obstruction
A good example of a fixed obstruction would be an ________.
endotracheal tube
T/F: Regardless of the tube size, the inner lumen of an endotracheal tube will generally be narrower than the trachea
T
If you put a smaller diameter tube (like an ETT tube) in the trachea, why would this cause increased airway resistance?
What type of flow volume loop obstruction is this describing and how would it affect the appears of the flow volume loop?
The smaller diameter leads to higher resistance, making it harder to get air in or out of the lungs. This obstruction affects both inspiration and expiration.
This is a fixed obstruction (intra and extrathoracic).
The flow-volume loop will be cut off at the top (expiration) and the bottom (inspiration) due to upper airway resistance, limiting the rate of airflow.
What does intra-thoracic mean?
lower down or within the chest
What does extra-thoracic mean?
above or outside the chest
A fixed obstruction is fixed because it affects both ________ and ________ throughout the respiratory cycle.
inspiration and expiration
This type of obstruction only affects expiration only, inside the chest.
Variable intrathoracic obstruction
With a variable extra-thoracic obstriction, negative pressure during inspiration can cause ____________ to collapse if they are not supported properly.
upper airways
With a variable intra-thoracic obstruction, during expiration, the pressure inside the chest becomes positive, which may lead to ________________ if the small airways aren’t robust, lack support, traction, or elastic recoil
airway collapse
Negative pressure during inspiration can pull the ________________ together, obstructing the airway.
vocal cords
With variable extra-thoracic obstruction, on expiration, the obstruction is pushed out of the way due to _________________.
positive airway pressure
If a patient with a variable extra-thoracic obstruction is on a mechanical ventilator, the positive pressure from the ventilator will push the obstruction out of the way during inspiration or expirtation?
inspiration
What is an example of a variable extrathoracic obstruction?
Paralyzed vocal cords, tracheal tumor, goiter, etc
anything that obstructs airflow outside of the chest
What is an example of a variable extrathoracic obstruction?
COPD, asthma
anything that obstructs airflow in side of the chest
What does FEV1 stand for?
forced expiratory volume in 1 second (volume you can get
out of the lungs using maximal effort in 1 second)
What does FVC stand for?
a vital capacity that is being forced out from TLC
If you are healthy, you should be able to move ________ of your ________ out of the lungs within a period of 1 second during maximal (effort) forced expiration. This is about ________ L.
80%; vital capacity; 3.6 L
If you are healthy, you move < 80% of your vital capacity out of the lungs within a period of 1 second during maximal (effort) forced expiration, what does this mean?
Something is wrong with your lungs
What is a normal FVC in liters?
4.5 L
How long should it take to empty the lungs all the way down to RV from TLC in a normal, healthy patient?
8 seconds [ADD PICTURE]
What is a normal FEV1 in liters?
3.5 L
If the FEV1 / FVC ratio is < 70%, what lung disease does this indicate?
Obstructive lung disease
If the FEV1 / FVC ratio is > 70%, what lung disease does this indicate?
Normal lungs or restrictive lung disease
A patient comes in for pulmonary function testing, what is the first test that is run and why?
Flow volume loop, because it is cheap and easy
What is the partial pressure difference of nitrogen between apex and the base of the lung?
Trick question, there should not be a major difference
What is the partial pressure of alveolar/lung nitrogen?
569 mmHg
Closing Capacity Test
During Phase 3, expired air is primarily coming from what part of the lung?
base of the lung
Closing Capacity
The base of the lung has ________, N2 dilution compared to the top of the long
more
Closing Capacity Test
As the lung move towards lower volumes, the ___________ of the lung gets emptier, we should expect more expired air to come from the ___________ of the lung
base ; apex
Closing Capacity
Why isn’t Phase 3 flat?
Initially, air is coming from the BASE of the lu ng and as Phase 3 progresses, air starts to come from the APEX of the lung.
This mixture of air coming from different parts of the lung is why Phase 3 isn’t flat.
Closing Capacity
Where is air coming from in Phase 3?
A mixture of air from all parts of the lung
Beginning of Phase 3 = air is coming from the base of the lung
End of Phase 3 = air is coming from the apex of the lung
Closing Capacity
