Exam 2 Flashcards
What does P IP & P PL stand for?
Pleural Pressure
- What does P A stand for?
Alveolar pressure
- What does P EL & P ER stand for?
Elastic recoil pressure
- What does P TP stand for?
Transpulmonary pressure
- What is the normal pleural pressure & when is it measured?
-5 cm H2O & measured in between breaths
- What is the normal P A pressure?
- 0 cm H2O
- It oscillates between -1(inspiration) & +1(expiration) cm H2O
- What does P EL refer to & what is its normal pressure?
- It refers to stretched out lung wanting to recoil
- The pressure is +5 cm H2O (equal & opposite to intrathoracic pressure)
- What is the formula for Transpulmonary pressure?
P TP= P A – P IP
- What does transmural pressure refer to?
Pressure available to fill up the lungs
What does a (+) transmural pressure indicate?
Availability to put air into the lungs
What is the chest wall’s normal resting tone?
Outward
What do the following letters stand for; C, a, A, V, D?
- C= Content
- a= arterial
- A= Alveolar
- V= Ventilation per min
- D= Gas absorbed/expired per min
How much oxygen (mg) does 1 dL have?
20mg
What is the formula for compliance?
Compliance= Delta V / Delta P
What is the formula for Elastance?
Elastance= Delta P / Delta V
When is someone’s peak lung function?
At age 20
What is the normal VT?
500mL
What is the normal FRC?
Normal functional residual capacity is 3.0L
What volume or capacity helps keep the lungs from collapse?
RV
What makes up the FRC?
ERV= 1.5 L & RV= 1.5 L
What is the lung volume at the end of maximal expiration?
1.5L only the RV is left
What is used as a buffer when we do not breath for a bit but already exhaled?
RV
What is the total lung capacity (TLC)?
6.0 L
What makes up Vital capacity (VC)?
- IRV= 2.5 L,
- VT= 0.5 L
- ERV= 1.5 L
What is the max IRV?
2.5 L
In the supine position, which lung volume(s) do not change?
RV, VT
In the supine position, which volume(s) decrease?
ERV, FRC
In the supine position, which volume(s) increase?
IRV
How long is the normal breathing cycle?
5sec total
- Inspiration= 2sec
- expiration= 2sec
- 1 sec in between
What changes does the PA undergo during expiration?
PA goes to +1 cm H2O at 1sec then back to 0 @ the end of expiration
What is the P ER at the end of inspiration?
-7.5 cm H2O
When is the max inspiratory Delta P for the alveoli?
It is @ 1sec of the inspiratory cycle. PA pressure is @ -1 cm H2O
What makes up the PVR?
Alveolar & Extraalveolar BV’s
How does lower lung volumes affect PVR?
There is a higher increase in Extraalveolar resistance than decrease in Alveolar resistance resulting in a higher PVR
How does higher lung volumes affect PVR?
There is a small decrease in Extraalveolar resistance & big increase in Alveolar resistance resulting in a higher PVR.
Does an increase or decrease in lung volume lead to a higher PVR?
Decrease
What happens to alveolar capillaries during inspiration?
They increase in length & decrease in diameter –> higher resistance
What happens to Extraalveolar vessels during inspiration?
The negative pressure pulls on the vessel walls increasing diameter & decreasing resistance.
How much dead space volume is there?
150 mL
What is the normal RR?
12 bpm
What does V E stand for?
Total minute ventilation
What do most pulmonary tests look at?
At expired air
What action is the better option to increase O2 saturation?
Increase depth of breath rather than RR
What is the formula for calculating tidal volume?
VT= VDS + VA
Where is the apex of the lung?
It extends superior passed the 1st rib
Where is the most movement of the lungs & how much is it?
At the base & it’s about 2cm
What seals the thorax & abdomen?
The central tendon
What are the 3 diaphragm openings, anterior to posterior?
- Caval aperture
- Esophageal aperture
- aortic aperture
What is the caval aperture?
Opening for the inferior vena cava
What nerve is connected to the diaphragm?
The L & R phrenic nerves
What prevents inferior thorax movement during inspiration?
The scalene muscles
The anterior scalene muscle connects to what structures?
The 1st rib & to C3 - C6
The middle scalene muscle connects to what structures?
The 1st rib & to C3 – C7
The posterior scalene muscle connects to what structures?
The 2nd rib & to C5 – C7
What structures make up the dead space?
- Trachea
- Bronchi
- Bronchioles
- Terminal bronchioles
What structures play part in actual air exchange?
- Respiratory bronchioles
- alveolar ducts
- alveolar sacs
How many generations does the conducting zone have?
16 generations
How many generations does the respiratory zone have?
7 generations
17 - 23
What is stridor?
Noise from an obstruction in the airway
What is hyperpnea?
Hyperventilation in excess of metabolic needs
What is orthopnea?
Body position changes cause difficulty breathing
What is the difference between looking blue & looking grey?
- Blue means the Hgb does not have O2 attached.
- Grey means Hgb is low.
At what point does cyanosis occur?
When Deoxy Hgb is > 5 gm/dL
What is hypoxia?
Decreased O2 amount at tissue level
What is hypoxemia?
Decreased O2 in arterial blood
What is hyper/hypocapnia?
Excessive/deficiency of CO2 in arterial blood
Air passes through the nose or mouth, to the___, and then to the___ and then into the tracheobronchial tree.
Pharynx & larynx
What constitutes the transitional zone?
Generations 17-19, the respiratory bronchioles
What all entails an acinus?
An acinus includes respiratory bronchiole, alveolar ducts & alveolar sacs distal to a single terminal bronchiole
What are the air pathway structures after the larynx to gas exchange?
Trachea ->
bronchi ->
bronchioles ->
terminal bronchioles ->
respiratory bronchioles ->
alveolar ducts ->
alveolar sacs
What is the structural difference from bronchi and bronchioles?
Bronchioles do not contain cartilage.
Clara cells secrete what?
- Proteins (SpA, B, C & D)
- lipids
- glycoproteins
- inflammatory modulator
What are the other functions of Clara cells?
- Metabolize foreign materials
- participate in airway fluid balance
- act as progenitor cells
About how many alveoli are in a healthy human being?
~ 480 billion
What allows for interalveolar communications?
The pores of Kohn
What is the ratio of Type I to Type II cells?
1:2
Type I cells cover about___% of the alveolar surface due to__?
90-95% Due to the larger surface area
What are the purposes of Type I cells?
- They allow for easy gas exchange
- Help remove liquid from the alveolar surface by pumping sodium & water into the interstitium.
What generates spontaneous automatic breathing?
Neurons located in the medulla
What causes the resting negative intrathoracic pressure?
The mechanical interaction in opposite directions between the lung and chest wall
What is contained in the intrapleural space?
About 15-25mL of a serous liquid
During inspiration the transmural pressure difference___ & the alveoli are distended, ___ alveolar pressure?
Increases & Decreasing
Alveolar pressure is equal to intrapleural pressure + _____?
Alveolar elastic recoil pressure
What establishes the pressure gradient for air flow?
Increasing alveolar volume lowers alveolar pressure
What mechanically transmits the pressure difference across alveoli?
The alveolar septa
What are the accessory inspiratory muscles & when are they involved?
- The sternocleidmastoid, the trapezius, & vertebral column muscles.
- They are involved during exercise, coughing, sneezing or pathologic state such as asthma
The diaphragm is considered part of the___?
Chest wall
When supine the diaphragm is responsible for ___ of the air entering during eupnea? What about standing?
- Supine is 2/3 &
- Standing is 1/3
The diaphragm is innervated by the ____, which leave the spinal cord at the __ thru the ___ cervical segments?
- Phrenic nerves
- 3rd & 5th
What holds the diaphragm to the lower 6 ribs & the sternum?
By 2 crura
During eupnea the diaphragm descends __ cm & during deep breathing is descends __ cm?
1-2cm & 10cm
The scalene muscles are accessory muscles?
False, they contract during eupnea, therefore are not accessory muscles
What muscles contract during normal expiration?
None, expiration is passive
In obese people the inspiratory muscle may also contract, when?
During early part of expiration
When does active expiration occur?
During exercise, speech, signing, sneezing, coughing, bronchitis.
Contraction of the internal intercostal muscles move the ribcage___?
Downward, opposite of the external intercostals
What is the I:E ration in eupnea?
1:2 or 1:4
During inspiration the alveolar pressures ___?
Decrease (-1 cm H2O)
Compliance is the inverse of ____?
Elastance
Elastance refers to?
Tendency for something to oppose stretch & its ability to return to its original state.
Surfactant has a lesser effect on surface tension during___ due to?
- Inspiration.
- Due to movement of surfactant from interior of the liquid phase to the surface during inspiration.
Many pathologic states shift the compliance curve to the___?
Right ( for any increase in transpulmonary pressure there is less of an increase in lung volume)
Fibrosis, atelectasis & thermal injuries ___ alveolar elastic recoil?
Increase. Fibrosis decreases compliance, therefore elastance is increased
Emphysema ___ compliance due to the destruction of the ___ tissue?
- Increases
- septal tissue, which opposes lung expansion.
Compliance in obese people is ___?
- Decreased.
- Moving the diaphragm downward is much more difficult
Abdominal distension & scars from burn injuries cause ___ chest wall compliance?
Decreased
How does someone with emphysema compensate?
With a greater RR & smaller Vt
Compliance is ___ dependent. When is it lower & greater?
- Volume
- lower at high volumes & higher at low volume
What is the normal compliance of the lung, in L/cm H2O?
0.2L/cm H2O
When is Elastin more compliant & important?
At low or normal lung volumes
What is the unit of measure for surface tension?
Dyn/cm
What is the formula for calculating (T)ension?
T= (P x r) / 2
Do smaller or larger alveoli have lower surface tension?
Smaller
Surfactant consists of?
- 85-90% lipids(75% phosphatidylcholine)
- 10-15% proteins
What is the functions of SP-A & SP-D?
Host defense
(D) for Defense
When does fetal surfactant production begin?
Around the fourth month of gestation.
What are the functions of surfactant?
- Maintain the stability of small airways
- Decrease work of inspiration by lowering surface tension –> reducing elastic recoil –> increasing compliance
Hypoxia or hypoxemia may lead to?
A decrease in surfactant production, inactivation or an increase in surfactant destruction
A lack of surfactant can temporarily be overcome by?
Ventilating someone with positive pressure (PEEP)
A lack of surfactant will lead to?
Increased elastic recoil of alveoli & spontaneous atelectasis.
What is alveolar interdependence?
Alveoli are polygons held open by the chest wall pulling on the outer surface of the lung. If an alveolus stars to collapse the surrounding alveoli will hold it open.
What is FRC?
- Volume of gas in the lungs at the end of eupnea.
- No muscles are actively contracting.
When are the elastic recoil & chest wall recoil equal?
At FRC
At high lung volumes the chest wall recoil pressure is positive or negative?
Positive
What are the FRC’s, in a healthy person, when standing & supine & at 30degrees?
- Standing= 3L
- Supine= 2L
- 30°= 2.5L
What kind of airflow is present in the trachea & larger airways?
Either turbulent or transitional
With what can alveolar pressure be measured?
With a body ple/thys/mo/graph
(4 syllable)
What is vital capacity?
Volume of air one is able to expire after maximal inspiration
Describe a FVC (Forced Vital Capacity) test & what is it used for?
- A person max inhales to TLC then gives max effort to exhale. Only the RV is left.
- It is used as a good index of expiratory airways resistance.
Lung volume is measured with a ___ & airflow rate is determined by using a ___?
Spirometer & (pneumo)(tacho)(graph)
What muscle(s) tighten the vocal folds?
- Cricothyroid muscles
- Vocalis muscle
What muscle(s) adduct the vocal folds?
- Thyroarytenoid muscles
- Transverse arytenoid muscle
- Lateral cricoarytenoid muscle
- (3x arytenoid, + 1x thyro + 1x crico)
What muscle(s) abduct the vocal folds?
Posterior cricoarytenoid muscles
What is the only extrinsic laryngeal muscle?
The Cricothyroid muscle
Which lobe is the largest & the smallest?
- Largest= Left Superior lobe
- Smallest= Left inferior lobe
What is in-between the thyroid cartilage & the cricoid cartilage?
The median cricothyroid ligament
Increased interstitial pressure leads to____ PVR due to____?
- Increased
- due to compression of vessels
How does positive pressure ventilation affect alveolar vessels?
They are compressed and derecruited
What intrapleural vessels are affected by positive pressure ventilation?
Extraalveolar & vena cava are compressed
What active influences can decrease PVR?
- ACh is #1
- beta-adrenergic agonists
- bradykinin
- nitric oxide
- PGE1
- prostacyclin
- PSNS stimulation
A, B2, N, P3
What active influences can increase PVR?
- alveolar hypoxia & hypercapnia
- angiotensin
- Alpha adrenergic agonists
- Epinephrine/Norepinephrine
- endothelin
- histamine
- PGF & PGE2
- pH (low mixed venous)
- SNS stimulation
- thromboxane
What is the partial pressure & percentage of atmospheric N2?
- 600.3 mmHg
- 79%
What is the partial pressure & percentage of atmospheric O2?
- 159.0 mmHg
- 21%
What is the partial pressure & percentage of atmospheric CO2?
0.3 mmHg & 0.04%
Describe perfusion of Zone 1?
- No perfusion during any part of the cardiac cycle.
- Higher resistance
- less recruitment
- lower intravascular pressures.
Describe perfusion of Zone 3?
- Perfusion is continuous due to higher pressures.
- Lower resistance
- more recruitment & distention.
Describe ventilation of Zone 1?
- Alveolar pressure is > arterial pressure, which is > venous pressure.
- Alveoli are larger
- less compliant
- less ventilation.
Describe ventilation of Zone 3?
- Arterial pressure is > venous pressure, which is > arteriolar pressure.
- Smaller transmural pressure gradient.
- More compliant & smaller alveoli.
Describe ventilation of Zone 4?
Zone 4 has continuous blood flow but perfusion is a bit lower than Zone 3 due to compression of the lung’s weight.
What is the blood flow like in Zone 2?
It is more of a pulsatile flow
When is PVR at the lowest point?
At FRC
Increasing lung volume leads to?
Decreased extra alveolar resistance & a big increase in alveolar resistance
How is resistance affected by decreasing lung volume?
- High increase in extraalveolar resistance
- slight decreased alveolar resistance
How does a cardiac index of 1.5 affect PVR?
Low blood flow results in a very high PVR
What is the formula for Partial pressure?
Pp= total pressure x gas concentration [Pp= 760 mmHg x 0.21 (O2)]
What is the humidity level at sea level?
Trick question, there is non for our purposes
How much O2 is absorbed each breath & per min?
1) Calculate inspiration. Use Pio2 of 149 mmHg –> O2= 149 mmHg / 760 mmHg= 19.61%.
2) 350 mL x 19.61%= 68.62 mL
3) Calculate expiration of O2: PO2 is 104 mmHg –> O2= 104 mmHg / 760 mmHg= 13.68%.
4) 350 mL x 13.68%= 47.89 mL.
5) 68.62 mL – 47.89 mL= 20.73 mL O2/breath.
6) 20.73 mL O2/breath x 12 bpm= 248.76 mL O2/min
What is the standard PicCO2?
0.3 mm Hg
What is the standard PiN2?
564.0 mm Hg
What is the standard Pi H2O?
47 mm Hg
What is the formula for inspired humidified gas?
PiO2= FiO2 (Pb – PH2O)
What does PB stand for?
Atmospheric pressure
How many mL of O2 are absorbed per 1 dL?
Around 5 - 6 mL (depending on rounding)
Calculation:
- O2 inhaled per breath= 68.6 mL
- O2 exhaled per breath= 47.6 mL
- 21 mL absorbed per breath
- 21 mL x 12= 252 mL
- Minute ventilation is 4,200 mL
- 4,200 mL dived by 100 (dL)= 42 dL
- 252 mL divided by 42 dL= 6 mL
How much CO2 is discarded per 1 dL?
4.5 mL
CO2 is very ____ but O2 is not?
Water soluble
What are the values for deoxygenated venous blood & venous CO2?
PvO2= 40 mm Hg PvCO2= 45 mm Hg
What are the PAO2, PACO2 & PAN2 after equilibration?
- PAO2= 104 mm Hg
- PACO2= 40 mm Hg
- PAN2= 569 mm Hg
What is the normal Interstitial capillary hydrostatic pressure?
– 4 mmHg
Lange gives a range of -5 to -7 mmHg
What is the normal interstitial capillary oncotic pressure?
~ 8 mm Hg
What happens when we have decreased colloids or diluted blood?
Extra fluid will accumulate in the lungs
What is the Starling Capillary Equation?
Qf= [ Kf(Pc – Pis) – 𝞂(πpl – πis) ]
What does 𝞂 stand for?
Reflection coefficient (ability of membrane to prevent leakage.
What does Kf stand for?
Capillary filtration coefficient (permeability characteristics of the membrane to fluids)
What happens to small blood vessels during inspiration?
Their diameter is reduced & increased in length –> increased resistance
What happens to extra-alveolar vessels during inspiration?
The negative pressure pulls on them –> increased diameter –> decreased resistance.
At low lung volumes, alveolar vessel resistance ___?
Decreases
What is the minimum PAO2 someone can still be healthy at?
40 mm Hg
What is the formula for Alveolar ventilation?
VA= RR x VA (VA per min= 12 x 350 mL)
How does increased metabolism affect PAO2 & PCO2?
- PAO2 is reduced
- PCO2 is increased
What happens to alveolar capillaries in responds to elevated CO2?
They constrict –> O2 being absorbed but no new air coming in & CO2 will build up.
What is HPV?
- Hypoxic pulmonary vasoconstriction.
- Areas with low perfusion get “constricted” to move fresh air to well perfused areas
What & why should someone with HPV not receive?
- Increased inspired O2.
- This will lead to O2 entering low or none perfused alveoli, which were previously constricted & take air away from functional areas
What happens if someone receives 100% FiO2 over several days?
Inflammation throughout the lung
How do anesthetics affect HPV?
All anesthetics knock out the HPV function
Squeezing ones’ abdomen results in ____ thoracic pressure?
Increased
At RV the apex is more/less compliant than the base?
- More.
- Base is most likely collapsed and increased pressure is needed to recruit them first.
Calculate FRC with the following values: Spirometer= 20L + 15% of that is Helium, final He concentration is 14%?
1) 20 L x 0.15%= 3L
2) X= 3 L / 0.14% = 21.43 L –> FRC= 1.43 L
What should one living in a basement in Michigan test for?
Radon (Rn), which is the 2nd leading cause of lung cancer
-Emphysema is a/n ___disease due to the ___ of ___.
- Obstructive,
- Loss & recoil
What ventilator mode should not be used in emphysema Pt’s?
Positive pressure ventilation –> small airways collapse
Fibrosis is a/n ___ disease leading to ___ compliance?
- Restrictive
- Decreased
What is Radon’s atomic number & weight?
86 & 222
Filling lungs strictly with water results in?
- No surface tension
- increased compliance
Surface tension makes up how much of the recoil tension?
2/3
Increased surface tension leads to?
Increased work to inhale
What slows down intrinsic digestion of the lungs?
Alpha1 Antitrypsin
What is ⍺1 A/T & where is it produced & with what disease is it inhibited?
- It is a antiprotease & is produced in the liver.
- Inhibited in emphysema
What happens to TLC, IC, FRC, VC, IRV, VT, ERV & RV in restrictive diseases?
They all are reduced.
SP-D & SP-A are ___ & SP-C & SP-B are ____?
Hydrophilic & Hydrophobic
What are the functions of surfactant’s lipids?
- Lower surface tension
- change proliferation & cytotoxicity of lymphocytes.
What are the functions of surfactant’s proteins?
- Enhance chemotaxis & phagocytosis
- Aggregation & opsonization of micro-organisms
- Inhibit the growth of pathogens
What is a normal V/Q ratio & how is it calculated?
- 0.8 L/min
- Calculated by V= 4.2 L/min / Q= 5 L/min
Zone 3 has a higher V/Q ration than Zone 1?
False, the lower lung has a lower V/Q despite increased perfusion
Compare expired PO2 & CO2 of the upper & lower lung?
- Upper lung will have higher PO2 & lower CO2.
- Lower lung will have lower PO2 & higher CO2
An airway obstruction will cause a ___ V/Q ratio?
Low (Low ventilation= usually low V/Q ratio)
How much lung volume is lost in the supine position?
About 1L
What happens to TLC, FRC, VC, VT, ERV & RV in obstructive diseases?
TLC, FRC, VT & RV are increased. VC & ERV are reduced.
Why is the RV important in healthy people?
It prevents the lungs from collapsing
Explain ERV?
Volume of gas expelled during max force. It starts after normal Vt expiration
IRV is determined by?
Strength of inspiratory muscles, inward elastic recoil of the lung & chest wall
What would be a normal reason for FRC to be lower than usual?
Exercise
When does IC begin?
At the end of normal expiration
Explain VC?
- Volume of air expelled during max forced expiration.
- Starts after maximal forced inspiration
What happens to the FRC, ERV, IRV, VC, RV & TLC when going from standing to supine?
- FRC decreases due to gravity no longer pulling on diaphragm.
- VC, RV & TLC do not change significantly but may slightly decrease d/t venous blood collecting in the lower extremities.
- ERV decreases.
- IRV increases
What lung volumes can be measured with a spirometer?
VT
IRV
ERV
IC
VC
FEV1
FVC
What lung volumes cannot be determined with a spirometer?
RV
FRC
TLC
Why is Helium used in PFT?
It is not taken up by pulmonary capillary blood & it does not diffuse out of the blood.
At what exact moment is the Helium-dilution technique stopped?
At the end of normal tidal volume
What is a reasonable estimate for anatomic dead space?
1 mL of dead space per pound of ideal body weight
How much CO2 comes from dead space?
Trick question, none
When seated which alveolar regions receive more ventilation per unit volume?
The lower regions.
Where in the lung is most ERV, IRV & IC located?
- ERV= In the upper portions
- IRV & IC= in the lower regions
Explain the air path when starting to inhale from RV?
The initial air enters the nondependent upper alveoli then the lower alveoli fill.
Where would airway closure most likely happen & why?
- In the lower parts of the lungs.
- The alveoli are smaller & have less recoil pressure.
Kyphoscoliosis is what kind of disease in relation to airway?
- A restrictive disease.
- It results in decreased compliance of the rib cage with much less outward recoil at low thoracic volumes & much greater inward recoil at higher volumes.
Why is the RV important in healthy people?
It prevents the lungs from collapsing
Explain ERV?
Volume of gas expelled during max force. It starts after normal Vt expiration
IRV is determined by?
Strength of inspiratory muscles, inward elastic recoil of the lung & chest wall
What would be a normal reason for FRC to be lower than usual?
During exercise
When does IC begin?
At the end of normal expiration
Explain VC?
Volume of air expelled during max forced expiration. Starts after maximal forced inspiration
What happens to the FRC, ERV, IRV, VC, RV & TLC when going from standing to supine?
- FRC decreases due to gravity no longer pulling on diaphragm.
- VC, RV & TLC do not change significantly but may slightly decrease d/t venous blood collecting in the lower extremities.
- ERV decreases
- IRV increases
What lung volumes can be measured with a spirometer?
VT, IRV, ERV, IC, VC & FEV1, FVC
What lung volumes cannot be determined with a spirometer?
RV, FRC & TLC
Why is Helium used in PFT?
- It is not taken up by pulmonary capillary blood &
- it does not diffuse out of the blood.
At what exact moment is the Helium-dilution technique stopped?
At the end of normal tidal volume
What is a reasonable estimate for anatomic dead space?
1 mL of dead space per pound of ideal body weight
How much CO2 comes from dead space?
Trick question, none
When seated which alveolar regions receive more ventilation per unit volume?
The lower regions.
Where in the lung is most ERV, IRV & IC located?
- ERV= In the upper portions IRV &
- IC= in the lower regions
Explain the air path when starting at RV?
The initial air enters the nondependent upper alveoli then the lower alveoli fill.
Where would airway closure most likely happen & why?
- In the lower parts of the lungs.
- The alveoli are smaller & have less recoil pressure.
Kyphoscoliosis is what kind of disease in relation to airway?
- A restrictive disease.
- It results in decreased compliance of the rib cage with much less outward recoil at low thoracic volumes & much greater inward recoil at higher volumes.
Increasing transmural pressure difference leads to___ vessel diameter & ___ resistance?
Increased & Decreased
With high lung volumes, resistance to blood flow offered by the alveolar vessels ___?
Increases greatly
How does positive-pressure ventilation affect alveolar & intrapleural pressures?
- Both pressure will be positive during inspiration.
- Alveolar & extraalveolar vessels are compressed & resistance to blood flow increases.
When would alveolar & intrapleural pressures be positive during inspiration & expiration?
- During positive-pressure ventilation w/ PEEP –> increased PVR & decreased transmural pressure differences.
- CV reflexes should adjust. If not CO will fall dramatically.
How does tripled CO affect PVR?
PVR is decreases passively due to recruitment, distention or both
Neural effects innervate which pulmonary vessels?
- Larger vessels are innervated more than smaller vessels.
- No innervation of vessels smaller than 30µm
When does perfusion cease?
When alveolar pressure is equal to pulmonary artery pressure
How does exercise affect Zones 1-3?
Zone 1 will turn into Zone 2 & the zone boundaries will move upward
How does the CNS control HPV?
Trick question, it does not. (Pg 111 in Lange)
How is HPV regulated on a cellular level?
Hypoxia inhibits an outward K+ current, which causes pulmonary vascular smooth muscle to depolarization, allowing calcium to enter the cells leading to contraction.
The K+ channel is open when oxidized & closed when reduced.
Lange page 111 (Hypoxic HPV)
How does alkalosis affect HPV?
It can interfere with HPV & open up previously closed areas.
How do ARDS, O2 toxicity & inhaled toxins lead to pulmonary edema?
Increase capillary permeability (Kf, 𝞂)
How do increased LA pressure, MS & too much IVF lead to pulmonary edema?
Increase capillary hydrostatic pressure (Pc)
How do rapid hemo/pneumothorax evacuation or upper airway obstruction lead to pulmonary edema?
Decreasing interstitial hydrostatic pressure (Pis)
How do protein starvation, diluted blood proteins & proteinuria lead to pulmonary edema?
Decrease the colloid osmotic pressure (πpl)
Label # 1 thru 6
1) Tubular myelin
2) Type 1 cell
3) Type 2 cell
4) Macrophage
5) Multivesicular bodies
6) Lamellar bodies
What is the Bohr’s equation to calculate physiologic dead space?
Vd / Vt = (Paco2 - Peco2) / Paco2
Example: Vd / 500 mL = (44 mmHg - 30 mHg) / 44 mmHg
–> Vd = (14 mmHg / 44 mmHg) x 500 mL
–> Vd = 0.318 mmHg x 500 mL
–> Vd = 159.01 mL
What is the formula to calculate alveolar oxygen tension?
PAO2 = FiO2 (PB - PH2O) - (PaCO2 / R)
Example:
–> PAO2 = 0.70% (760 mmHg - 47 mmHg) - (40 mmHg / 0.8)
–> PAO2 = (0.70% x 711 mmHg) - 50 mmHg
–> PAO2 = 499.1 mmHg - 50 mmHg
–> PAO2 = 449.1 mmHg
PiO2 can be substituted with what?
PiO2 = FiO2 (PB - PH2O)
What is the formula to calculate A-a gradient?
PAO2 = PiO2 - ( PaCO2 / R )
PiO2 can be substituted with [ FiO2 x (PB - PH2O) ]