Lecture 2/27 - Pulmonary Flashcards
Test 2
The pulmonary artery and vein are considered ________ blood
systemic
What is the alveolar pressure of O2?
PAO2 = 104 mmHg
What is the systemic pressure of O2 in the L atrium? Why?
100 mmHg
pulm venous blood is diluted with bronchiolar admixtures
Tissue in the lungs has its own ____________, which makes up ___% of CO. What is the function of this?
circulatory system
1%
Its function is to deliver nutrients to parts of lungs that cant get it from pulmonary blood.
How does age affect PAO2?
It should be 104 mmHg in someone who is in good health and 20 yrs old
This number starts to decrease EVEN WITH PERFECT HEALTH after the age of 20 yo
At what age do your organs start deteriorating?
40 yo
At what age does your PAO2 decrease?
20 yo
What is your PAN2 (nitrogen)?
569 mmHg
Increase minute ventilation = ________ in O2 & __________ in CO2 in regards to PA. How are these numbers for reflected
Increase
Decrease
Reflected in blood gases
T/F: if we increase blood flow to the lungs the alveolar gas pressures will be the same
F
The numbers will be different
What does the dot over an abbreviation mean?
Over a minute
What is the abbreviation for minute ventilation?
V̇E
Technically, what should minute ventilation be?
Tidal volume x RR
VT =
VD + VA
Tidal volume = Dead space ventilation + perfused Aveolar ventilation
Ex) 500 = 150 + 350
V̇E =
V̇D + V̇A
(VD x RR) + (VA x RR)
Ex) 6000 ml = (150ml x 12) + (350ml x 12)
What are the 3 types of dead space? Describe them
- Anatomical: conducting zone in upper airway
- Alveolar dead space: w/i lungs –> alveoli that are not perfused w/ ventilation
- Physiological: combo of anatomical & alveolar dead space
What is an example of Alveolar dead space?
PE
Which type of dead space occurs in unhealthy lungs?
alveolar dead space
When should you have alveolar dead space?
If over the age of 20 and/or bad health
You inhale/exhale 500 cc of indicator gas. What happens to it?
During inspiration:
-150 cc of that gas stays within the anatomical dead space
-350 cc is diluted in the 3L thats already
Expiration:
-150cc of gas (100% indicator) that was in dead space is pushed out
-350cc of diluted mixture from lungs is exhaled
Whats taken in/out are both diluted
In the ________ there is a small amount of gas exchange. This area consist of the ____________
Transitional zone
Respiratory bronchioles
T/F: anatomical dead space has no purpose
F
The 150 cc of air is used to push the other 350cc of air further into the lungs for gas exchange
What is normal V̇A
4200 ml/min
Increase ventilation = _________ PAO2
Increase
Decrease ventilation = _________ PAO2
decrease
Normal PACO2 is
40 mmHg
Increased ventilation = ______ PACO2
decreased
Decreased ventilation = ______ PACO2
increased
With increased ventilation PACO2 will be _________ more than normal
diluted
What is increasing ventilation good for and why? Decreasing?
Increasing ventilation –> decreases PACO2
–Good for respiratory/metabolic acidosis
Decreasing ventilation –> increases PACO2
–Good for temp correction of respiratory alkalosis
Pulmonary Capillary starling forces: Pis
-8 mmHg
(Pulmonary interstitum)
Pulmonary Capillary starling forces: Pc
7 mmHg
(Pulmonary Capillary)
Pulmonary Capillary starling forces: 𝝅is
14 mmHg
(interstitum protein oncotic/osmotic)
Pulmonary Capillary starling forces: 𝝅pl
28 mmHg
pulmonary blood oncotic
Which starling force is the only one that holds fluid in?
Pulmonary blood oncotic of 28 mmHg
What are the starling forces that favor filtration?
Pulm interstitum
interstitum protein oncotic
pulmonary cap
What is the net filtration in the pulmonary capilaries
+1 mmHg
Why is pulmonary interstitial pressure -8?
systemic: -3 from lymphatics
pleural pressure surrounding lungs -5
combine them both = -8mmHg
What can affect the lymphatic system in the lungs? What effects will this have?
Ventilation with increased pressure
-tumor
basically anything thats gonna compress the lymphatics similar to compressing the pulmonary vessels
Effects: Lymphatics unable to suck extra water from lungs –> pulm edema
T/F: O2 is very water soluble. What considerations should I have with this?
F
It is not, hence why its carried by hgb and lungs need to be dry to make sure O2 is absorbed.
What is L AP?
L atrial pressure = 2 mmHg
What does LAP increase to before we start to see pulm edema? What is this considered?
23 mmHg
A safety net before fluid builds up in the lungs
What pathologies can cause pulmonary edema?
L heart failure
-Blood loss dt decreased oncotic pressure
What is the pulmonary starling forces formula?
Qf = Kf[(Pc - Pis) - (𝝿pl - 𝝿is)]
Kf =
Capillary filtration coefficient
Describes the permeability of the membrane to fluids
What are pathologies that increase capillary permeabiliry (Kf) (4)? What does this cause?
ARDS
-Infection
-O2 toxicity
-Inhaled/circulating toxins
Caps more porous –> increase colloids in interstitum –> pulm edema
What are pathologies that increase capillary hydrostatic pressure (Pc) (4)? What does this cause?
Increased BP
-increased LAP
-left ventricle infarct
-mitral stenosis
Pulmonary edema
What are pathologies that decrease interstitial hydrostatic pressure (Pis) (1)? What does this cause?
Rapid evacuation of pneumothorax/hemothorax (“chest tube stripping”)
Pulmonary edema
What are pathologies that decrease colloid osmotic pressure (𝝿pl) (3)? What does this cause?
Protein starvation (not eating enough protein/amino acids)
-dilution of blood by IV fluids
-Renal problems, resulting in protein loss (proteinuria)
Pulmonary edema
What are you pathology that decrease pulmonary lymphatic drainage (3)? What can this lead to?
-pulmonary tumors
-interstitial fibrosis diseases
Pulmonary edema
What are pathology of unknown etiologies that cause pulmonary edema? (3)
-high altitude
-Head injuries
-drug overdose
What causes flash pulmonary edema? Give example.
Very negative pressures in the chest dt young/strong person trying to inspire against a closed airway.
What is the lowest PIP someone can get to?
-60 cmH2O
T/F: Flash pulmonary edema is easy to treat
F
hard to treat
T/F: we are more worried about flash pulmonary edema in older people than younger people
F
More worried about it in younger people because they are stronger and able to pull in a lower pleural pressure
Where is ventilation the greatest at in the lung? least? why?
Greatest: bottom of lung
Least: top of lung
This is bc theres more perfusion towards the base of the lung or in ZONE 3 of the lung
PLEASE REMEMBER:
base of the lung is the bottom of the lung which doesnt change
-zone 3 does change and ALWAYS has the highest blood flow
What is the definition of V/Q matching?
When Ventilation and perfusion ratios match in the lungs.
If Q increases then V shoud _______
increase
This is good V/Q matching
The lung is suspended in the chest and attached to what?
Hilum
At FRC, What is the pleural pressure gradient in an upright lung?
-1.5 cmH2O (bottom) to -8.5 cmH2O (top)
At FRC, How does pleural pressure gradient relate to Aveolar fullness? How does this affect compliance?
-8.5 cmH2O pressure at top of lungs stretches alveoli out and makes them more full –> less air accepted –> less compliant at FRC
-1.5 cmH2O pressure at bottom of lungs makes them less full –> more readily accepts air –> more compliant at FRC
At FRC, At the top of the lung the pleural pressure is about ______ and the alveoli are about ______% full
-8.5 cmH2O
60%
At FRC, At the bottom of the lung the pleural pressure is about ______ and the alveoli are about ______% full
-1.5 cmH2O
25%
At FRC, What is the lowest alveolar capacity in healthy lungs? What does this mean?
20%
Small airway will collapse if you try to empty alveoli less than 20% capacity
At FRC, There is _____ compliance at the base of the lung and _____compliance at the top of the lung.
increased
decreased
What is alveolar compliance based on?
How much air an alveolar will accept
At FRC, What is PTP at the base of the lung?
1.5 cmH2O
PA = PIP + PTP
0 = -1.5 + PTP
At FRC, A ______ amount of PTP is needed to put a large amount of volume in the bottom of the lung.
small
At FRC, What happens at the top of the lungs as PTP increases?
It becomes harder to put more volume into the top of the lungs –> compliance decreases
At FRC, A ______ amount of PTP is needed to put a small amount of volume in the top of the lung.
large
The lung is more compliant during _______. What is this concept called?
Expiration
Hysteresis
What is hysteresis in the lungs?
The difference in compliance with inspiration and expiration
expiration more compliant
What is RV?
1.5 L
We have force exhaled out all the air we can
We are left with 1.5 L
At RV, plural pressure is more _________, which allows us to have ________ lung volumes
Positive
Lower
At RV, what is the pleural pressure range?
Bottom: +4.8 cmH2O
Top: -2.2 cmH2O
At RV, what is the PTP at the top of the lung? Base? What does this mean?
Top: 2.2 cmH2O
Base: -4.8 cmH2O
The base of the lung has a negative transpulmonary pressure –> alveolar collapse
At RV, what is the slope of the V/PTP line at the base of the lung?
0
At RV, At the top of the lung the pleural pressure is about ______ and the alveoli are about ______% full
-2.2 cmH2O
30%
At RV, At the base of the lung the pleural pressure is about ______ and the alveoli are about ______% full
+4.8 cmH2O
20% – This is the MINIMUM amount of air an alveoli can have
At RV, the _______ is more compliant
apex/top of the lung
At RV, the 1st portion of inspired air goes to the ____ of the lung. Why?
top
Top of the lung is available to accept air & airways are actually open
Bottom airways are collapsed at the beginning of inspiration at RV
How do you get air in the base of the lungs at RV?
Air volume has to go to the top of the lung 1st –> stetches bottom lung alveoli open (walls are connected) –> opens airway to bottom alveoli –> air able to come in
At RV, what pathologies will prevent the base alveoli from being able to be stretched open by the top alveoli to recieve air?
Missing elastic/connective tissues –> fibrosis & COPD
What is an example of how V/Q mismatch happens?
At RV
Blood moving thru base but no fresh air –> messes up blood gasses
This is why our bodies dont hang out at RV –> hang out at FRC
What considerations should we have with GA regarding lung volume?
body position: pt on back –> decreases lung volume
NMB/Sedatives: relaxes muscles –> decreases lung volume
These values may look silimar to RV… REMEMBER we dont like to hang out here
This can cause a V/Q mismatch!!!!
Need increased pressures to maintain volumes
The top of the lung has a ______ PIP than the bottom of the lung
more negative
The top of the lung has a ______ PTP than the bottom of the lung
Greater
_______ will keep the alveoli more distended
Increased PTP
The alveoli are bigger in the ______ of the lung and the pulmonary vessels are bigger in the _____ of the lung. What is this dt?
apex
base
this is dt the fact that we are mostly in the upright position and the alveoli and vessels in the areas are mostly full and are physiologically bigger.
What is the most important lung perfusion technique?
HPV: hypoxic pulmonary vasoconstriction
What is HPV?
Hypoxic pulmonary vasoconstriction
decrease ventilation in a area of a lung –> blood vessels constrict upstream to hypoxia in alveoli –> direct blood to better parts of lung –> decreases flow to that area with decreased ventilation
What are the two mechanisms that help prevent V/Q mismatch?
HPV
Hyperoxia (airway smooth muscle contraction)
What are the two sets of smooth muscles in the lungs? What do they do?
- Pulmonary vessels: constrict/relax upstream of pulmonary caps.
- Airway smooth muscle: constricts/relax to direct ventilation or perfusion where it’s needed
Why do we supplement our GA with O2?
Most of our GA opens K+ channels –> relaxes vascular smooth muscle –> interfers w/ body’s ability to redirect blood to follow ventilation
What happens to PAO2 and PACO2 when you have a PE of a mismatch V/Q?
It will be identical to inspired humidified environment air
PAO2 = 149 mmHg
PACO2 = 0 mmHg
During a PE, what is happening?
We are ventilating an area of the lung w/ no alveolar blood flow –> PAO2 increases to 149 mmHg –> airway smooth muscles senses this –> constricts to prevent ventilation to an area thats not being perfused –> ventilation directed to other places in lung that are being perfused
What is a stimulant for airway smooth muscle constriction?
hyperoxia
Normal PAO2 = 104
________ is a stimulant for smooth muscle constriction. What does this help with?
Hyperoxia
Helps prevent alveolar dead space ventilation
What happens if you put a patient on FI02 100% for a day?
Increase PAO2 –> capillaries more porous –> airway smooth muscles constrict/more reactive
why we don’t want pt on 100% FI02 if they don’t need it
Increase O2 beyond a pts needs can cause what?
Airway reactivity
Porous capillaries
T/F: you are able to ventilate in ARDS
F
If you block the airway, what will happen to the gas pressures in the alveoli?
PAO2: decrease
PACO2: increase
What is the FRC when supine? How much was displaced? Why?
2L
1L
lay down on back –> abd/intestines slide up & push on inferior part of diaphragm –> push air out lungs
What other pathology can displace air volume at FRC when supine?
Obesity
Being top heavy
Pregnancy
How does volume/capacities change when going from upright/standing to supine?
IRV increased
-ERV decreased
VT, RV, VC unchanged
What does a spirometer do?
Measures lung volumes/capacities
The bell in the spirometer goes ______ with expiration
up
With spirometry: breathing normally
Tidal volume tracing
With spirometry: breathing all the way in
Vital capacity tracing
With spirometry: at the end of next breath push all air out
ERV tracing
With spirometry: at the end of normal inspiration keep inspiring
IRV tracing
