Exam III- Spring 2024 Flashcards
What is the formula to calculate Transpulmonary Pressures (PTP)? What other pressure does this formula work for?
- PTP= Aveolar Pressure (PA) - Pleural Pressure (PIP)
- Elastic Pressure (PEL)
What is the formula for Tidal Volume?
What is the formula in minute ventilation?
What are the normal values for each?
- VT= VDS + VA
- Minute Vent= VT x (RR)
- Resp. Rate= 12 bpm
- Tidal Volume= 500 mL; 6 L/min
- Dead Space Volume= 150 mL; 1.8 L/ min
- Aveolar Volume= 350 mL; 4.2 L/ min
What are the normal volumes for:
Tidal Volume
Residual Volume
Expiratory Reserve Volume
Inspiratory Reserve Volume
- TV= 500 mL
- RV= 1.5 L
- ERV= 1.5 L
- IRV= 2.5 L
Which volumes make up the following capacities and their normal values:
Total Lung Capacity
Inspiratory Capacity
Functional Residual Capacity
Working/ Vital Capacity
- TLC= 6 L
- IC= IRV+VT= 3.0 L
- FRC= ERV+RV= 3.0 L
- VC= IRV+VT+ERV= 4.5 L
PA>Pv>Pa
- West Perfusion Zone 1
- no blood flow
- In a healthy lung, there should not be a zone 1
Pa>PA>Pv
- West Perfusion Zone 2
- Pulsatile flow; “In between”
- Pulsatile blood flow during higer pressures times of the cardiac cycle and tapers off with a lower pulm blood pressure
- top portions of the lung
Pa>Pv>PA
- West Perfusion Zone 3
- Continuous flow; “always on”
- Normally in the bottom 1/2 of the lung
The effects of the weight of the lung on blood flow at the very base of the lung that sits on the diaphragm
- West Perfusion Zone 4
- A subset of Zone 3; reduces the amount of blood flow in the very bottom portion of the base
- the weight of the lungs compress the easily collapsable pulm vein and arteries
When does cyanosis occur as it pertains to deoxyhemoglobin?
When deoxyhemoglobin >5 g/ dL
What is the Fick Equation for C.O.?
CO= O2 absorbed per min (mL/ min)/ Arteriovenous O2 difference (ml/ L)
What is Guyton’s formula for calculating PVR?
What is normal?
PVR= MPAP-LAP/ C.O.
Normal= .14 PRU
What is Miller’s Formula for calculating PVR?
What is normal?
PVR= MPAP- PAWP/ C.O. (x 80 converts units to CGS)
Normal= 96 mmHg/L/min
What is a CGS?
What are its units?
What is the equivalent PRU?
- Centimeters Gram Second
- mmHg/ L/ min or dyne x sec/ cm^5
- 1 CGS= 1333 x PRU
What volumes make up the vital capacity?
Expiratory Reserve Volume (ERV), Tidal Volume (TV), and Inspiratory Reserve Volume (IRV)
What volumes make up functional residual capacity (FRC)?
ERV, RV
Alveolar resistance gets higher ___ , gets lower ___
Lung volumes get higer; as lung volume gets lower
The higher the pulmonary blood flow, the lower the ______.
PVR
What are the two ways that our body reduces PVR when C.O. increases?
Recruitment and distension
What happens with right heart failure?
With decreased C.O., lungs decruit and vessels narrow, increasing PVR, increasing afterload for RH
What would increase PVR?
- Decreased/ Increased lung volume (above FRC)
- Decreased RH C.O.
- PPV
- Loss of alveoli
- Increased Interstitial pressure
What would decrease PVR?
- Increased C.O.
- Increased PAP
- Increased LAP
What are the pulmonary capillary pressures?
- Pc= 7 mmHg
- ∏p= 28 mmHg
- Pic= -8 mmHg
- ∏if= 14 mmHg
What is the formula for calculating net filtration and net flow?
- Net filtration= Pc-Pif-∏p+∏if
- Net flow= Kf x (Pc-Pif) - (∏p-∏if)
HPV is primarily an effect of what gas?
Primarily O2; secondarily CO2
2/3 of lungs elastic recoil pressure is ____ ____ and 1/3 is from the ____ itself.
Which is more important?
Surface tension; Tissue
The behavior of the tissue is most important because as long as the lungs are healthy, there should always be enough surfactant.
Top of lung doesnt get emptier than ?
Bottom lung doesn’t get emptier than ?
Top: 30%
Bottom: 20%
FRC intrapleural pressure:
RV intrapleural pressure:
FRC: -5 cm H2O (-8.5; -1.5)
RV: +2 cm H2O (-2.2; +4.8)
Functions of Club Cells
- Found in the bronchioles, produces surfactant at much lower rate than alveoli type II cells
- Progenitor cell for damaged areas of lungs
Type 1 and Type 2 alveolar cell percentage
- Type 1: 90-95% of alveolar surface area
- Type 2: 5-10% of alveolar surface area
Increasing lung volume does what to PVR? Why?
Increases
At very high lung volumes Total PVR is elevated because Alveolar resistance is elevated
Decreasing lung volume does what to PVR? Why?
Increases
At very low lung volumes Total PVR is elevated because extraalveolar resistance is elevated
Decreasing lung volume does what to airway resistance?
Decreases
FRC volumes standing v supine
Standing- 3 L
Supine- 2 L
FRC drops in supine pt because of?
reduction in ERV
“…diaphragm is getting pushed up from all the mass of the stuff that’s in your abdomen. So the volume that gets squeezed out is the ERV. “
What is the normal airway compliance value for the lungs?
200 mL/ per cm H20
____% of expired air should be CO2
5%
At what transpulmonary pressure is TLC?
25-30 cm H2O
What are the effects on volumes and capacities with Restrictive Lung Disease?
- Decrease: RV, ERV, TV, VC, FRC, and TLC
- IRV may be low to normal depending on how the stage of disease
What are the effects on volumes and capacties with Obstructive Lung Disease?
- Large increase in TLC
- Increase RV –> decrease in ERV and IRV
- VC decreases and is almost equal to TLC as the disease worsens
Which of the following conditions are reasonable explanations for a patient’s decreased static pulmonary compliance (the pressure-volume curve for the lungs shifted to the right)?
- Decreased functional pulmonary surfactant
- Fibrosis of the lungs
- Surgical removal of one lobe
- Pulmonary vascular congestion
Which of the following tend to increase airways resistance?
- Stimulation of the parasympathetic postganglionic fibers innervating the bronchial and bronchiolar smooth muscle
- Low lung volumes
- Forced expirations
- Breathing through the nose instead of the mouth
Which of the following statements concerning alveolar pressure
is/are correct?
a. Alveolar pressure is lower than atmospheric pressure during a
normal negative-pressure inspiration.
b. Alveolar pressure is greater than atmospheric pressure during
a forced expiration.
c. Alveolar pressure equals the sum of the intrapleural pressure
plus the alveolar elastic recoil pressure.
d. Alveolar pressure equals atmospheric pressure at the end of a
normal tidal expiration.