Lectures 9 & 10: Pulmonary (Exam II) Flashcards
What is atmospheric pressure?
760mmHg or 1atm
What is PIP?
- Pleural Pressure = -5cmH₂O
What is PA?
What does it normally measure?
Alveolar pressure = -1(inspiration) to +1(expiration) cmH₂O normally.
What is PEL ?
Elastic recoil pressure: the tendency of the inflated lung to recoil back from its inflated state to a deflated state.
(+5 cmH₂O)
What is another term for PEL?
PER
What is a transmural pressure?
The difference of two pressures that have a wall separating them.
What is the formula for PTP (Transpulmonary Pressure)?
PTP = PA - PIP
If cut, what would occur to the ribs? Why?
Ribs would pop out due to the elastic forces of the cartilage and intercostal muscles.
Given PA= 0 and PIP = -5, what would PTP be?
PTP = PA - PIP
PTP = 0 - (-5) = +5 cmH₂O
A pneumothorax would cause what pressure to disappear?
PIP
When do the lungs start to degrade?
At 20yrs old
Which of the following lung volume/capacity diagrams would be indicative of someone standing and which would be indicative of someone laying supine? Why?
- Left is standing:
- Right is supine: supine will ↑abdominal pressure on the diaphragm and reduce FRC.
Why is pre-oxygenation so important for induction?
Supine positioning decreases FRC. Pre-oxygenation counteracts this loss of FRC.
What would be indicated by 2 on the figure below?
VT = 0.5L
What would be indicated by 1 on the figure below?
What is this?
- Inspiratory Reserve Volume (IRV) = 2.5L
- The inspiratory capability of the patient beyond VT.
What would be indicated by 11 on the figure below?
How would this be calculated?
- Inspiratory Capacity (IC) = 3L
- IRV + VT = IC
What would be indicated by 5 on the figure below?
Maximal Inspiration
What would be indicated by 3 on the figure below?
What is this?
- Expiratory Reserve Volume (ERV) = 1.5L
- The amount of air that can be exhaled purposefully by using the abdominal muscles to push up on the diaphragm.
What would be indicated by 9 on the figure below?
What is this and how is it calculated?
- Vital Capacity (VC) = 4.5L
- VC = IRV + VT + ERV
- This is the “working volume” of the lungs (the total amount of air we are capable of moving).
What would be indicated by 6 on the figure below?
Point of maximal expiration
At what point would there no longer be any air in the lungs at all?
7
What would be indicated by 4 on the figure below?
What is this?
- Residual Volume (RV) = 1.5L
- Air left in the lungs after maximal expiration (This can’t be exhaled out)
What would be indicated by 10 on the figure below?
What is this and how is it calculated?
- Functional Residual Capacity (FRC) = 3L
- FRC = ERV + RV
- This is the amount of air the lungs as a baseline
What lung volume/capacity keeps the lungs open and is a buffer against periods of apnea?
FRC
What would be indicated by 12 on the figure below?
What is this and how is it calculated?
- Total Lung Capacity (TLC) = 6L
- The total volume of both lungs at their max.
- TLC = IC + FRC
As one gets older, the loss of ____ necessitates the increasing of expiratory time.
PER
How long is a typical respiratory cycle?
How long is inspiration?
Expiration?
- 5 seconds
- 2 seconds
- 2 seconds
There’s supposed to be a 1 second pause in-between inspiration and expiration.
What is depicted below?
VT during a respiratory cycle
What is depicted in the figure below?
Intrapleural Pressure (PIP) in cmH₂O during the respiratory cycle.
What causes the change in chest pressure at 2 seconds in the figure below?
Diaphragm relaxation.
What is depicted in the figure below?
Airflow in L/s during the respiratory cycle
What is depicted in the figure below?
Alveolar pressure (PA) in cmH₂O during the respiratory cycle.
Describe what is occurring the figure below.
Changes in FRC according to positional change.
If during an expiration the PTP = -7 cmH₂O then what would PEL equal?
+ 7 cmH₂O
What will occur when PER is greater than PIP?
Lungs will recoil back to baseline
When is PA a positive number?
During expiration
When would PA = 0 cmH₂O ?
At the end of expiration
As PIP decreases (becomes increasingly negative) so does ______.
Why is this?
- PA
- Negative intrapleural pressure causes expansion, pulling out the alveoli and making the alveolar pressure negative as well, thus drawing in fresh air.
When does the most negative PA occur?
What is the the most negative PA?
PA = -1 cmH₂O at 1second of inspiration.
When does the fastest inspiratory airflow occur?
At 1 second of inspiration = most negative PA = greatest inspiratory flow.
What lung zone is depicted by 1 in the figure below?
What pressures would be exhibited by this lung?
- Zone 1
- PA > Pa > Pv
How much blood flow is seen in a Zone 1 lung? Who has Zone 1 lungs?
- Very little to no blood flow. Zone 1 lungs are a pathologic condition.