Lectures 9 & 10: Pulmonary (Exam II) Flashcards

1
Q

What is atmospheric pressure?

A

760mmHg or 1atm

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2
Q

What is PIP?

A
  • Pleural Pressure = -5cmH₂O
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3
Q

What is PA?
What does it normally measure?

A

Alveolar pressure = -1(inspiration) to +1(expiration) cmH₂O normally.

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4
Q

What is PEL ?

A

Elastic recoil pressure: the tendency of the inflated lung to recoil back from its inflated state to a deflated state.

(+5 cmH₂O)

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5
Q

What is another term for PEL?

A

PER

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6
Q

What is a transmural pressure?

A

The difference of two pressures that have a wall separating them.

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7
Q

What is the formula for PTP (Transpulmonary Pressure)?

A

PTP = PA - PIP

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8
Q

If cut, what would occur to the ribs? Why?

A

Ribs would pop out due to the elastic forces of the cartilage and intercostal muscles.

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9
Q

Given PA= 0 and PIP = -5, what would PTP be?

A

PTP = PA - PIP

PTP = 0 - (-5) = +5 cmH₂O

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10
Q

A pneumothorax would cause what pressure to disappear?

A

PIP

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11
Q

When do the lungs start to degrade?

A

At 20yrs old

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12
Q

Which of the following lung volume/capacity diagrams would be indicative of someone standing and which would be indicative of someone laying supine? Why?

A
  • Left is standing:
  • Right is supine: supine will ↑abdominal pressure on the diaphragm and reduce FRC.
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13
Q

Why is pre-oxygenation so important for induction?

A

Supine positioning decreases FRC. Pre-oxygenation counteracts this loss of FRC.

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14
Q

What would be indicated by 2 on the figure below?

A

VT = 0.5L

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15
Q

What would be indicated by 1 on the figure below?
What is this?

A
  • Inspiratory Reserve Volume (IRV) = 2.5L
  • The inspiratory capability of the patient beyond VT.
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16
Q

What would be indicated by 11 on the figure below?
How would this be calculated?

A
  • Inspiratory Capacity (IC) = 3L
  • IRV + VT = IC
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17
Q

What would be indicated by 5 on the figure below?

A

Maximal Inspiration

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18
Q

What would be indicated by 3 on the figure below?
What is this?

A
  • 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.
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19
Q

What would be indicated by 9 on the figure below?
What is this and how is it calculated?

A
  • 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).
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20
Q

What would be indicated by 6 on the figure below?

A

Point of maximal expiration

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21
Q

At what point would there no longer be any air in the lungs at all?

A

7

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22
Q

What would be indicated by 4 on the figure below?
What is this?

A
  • Residual Volume (RV) = 1.5L
  • Air left in the lungs after maximal expiration (This can’t be exhaled out)
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23
Q

What would be indicated by 10 on the figure below?
What is this and how is it calculated?

A
  • Functional Residual Capacity (FRC) = 3L
  • FRC = ERV + RV
  • This is the amount of air the lungs as a baseline
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24
Q

What lung volume/capacity keeps the lungs open and is a buffer against periods of apnea?

A

FRC

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25
Q

What would be indicated by 12 on the figure below?
What is this and how is it calculated?

A
  • Total Lung Capacity (TLC) = 6L
  • The total volume of both lungs at their max.
  • TLC = IC + FRC
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26
Q

As one gets older, the loss of ____ necessitates the increasing of expiratory time.

A

PER

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27
Q

How long is a typical respiratory cycle?
How long is inspiration?
Expiration?

A
  • 5 seconds
  • 2 seconds
  • 2 seconds

There’s supposed to be a 1 second pause in-between inspiration and expiration.

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28
Q

What is depicted below?

A

VT during a respiratory cycle

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29
Q

What is depicted in the figure below?

A

Intrapleural Pressure (PIP) in cmH₂O during the respiratory cycle.

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30
Q

What causes the change in chest pressure at 2 seconds in the figure below?

A

Diaphragm relaxation.

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31
Q

What is depicted in the figure below?

A

Airflow in L/s during the respiratory cycle

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32
Q

What is depicted in the figure below?

A

Alveolar pressure (PA) in cmH₂O during the respiratory cycle.

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33
Q

Describe what is occurring the figure below.

A

Changes in FRC according to positional change.

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34
Q

If during an expiration the PTP = -7 cmH₂O then what would PEL equal?

A

+ 7 cmH₂O

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35
Q

What will occur when PER is greater than PIP?

A

Lungs will recoil back to baseline

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36
Q

When is PA a positive number?

A

During expiration

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37
Q

When would PA = 0 cmH₂O ?

A

At the end of expiration

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38
Q

As PIP decreases (becomes increasingly negative) so does ______.
Why is this?

A
  • PA
  • Negative intrapleural pressure causes expansion, pulling out the alveoli and making the alveolar pressure negative as well, thus drawing in fresh air.
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39
Q

When does the most negative PA occur?
What is the the most negative PA?

A

PA = -1 cmH₂O at 1second of inspiration.

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40
Q

When does the fastest inspiratory airflow occur?

A

At 1 second of inspiration = most negative PA = greatest inspiratory flow.

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41
Q

What lung zone is depicted by 1 in the figure below?
What pressures would be exhibited by this lung?

A
  • Zone 1
  • PA > Pa > Pv
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42
Q

How much blood flow is seen in a Zone 1 lung? Who has Zone 1 lungs?

A
  • Very little to no blood flow. Zone 1 lungs are a pathologic condition.
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43
Q

What lung zone is depicted by 2 in the figure below?
What pressures would be exhibited by this lung?

A
  • Zone 2
  • Pa > PA > Pv
44
Q

What lung zone is depicted by 3 in the figure below?
What pressures would be exhibited by this lung?

A
  • Zone 3
  • Pa > Pv > PA
45
Q

What lung zone exhibits pulsatile blood flow?
What lung zone exhibits non-pulsatile continuous blood flow?
What is the reasoning for the difference?

A
  • Pulsatile = Zone 2
  • Continuous = Zone 3
  • Gravity: ↑ pressure = ↑ perfusion
46
Q

What lung zone is depicted by 1 in the figure below?

A

Zone 4

47
Q

What causes the decrease in blood flow at the very bottom of the lung depicted by the red circle in the figure below?

A
  • Zone 4 decreased blood flow occurs from compression from the lung above as well as the diaphragm.
48
Q

What would occur with alveolar capillaries during inspiration?

A

↑ capillary length & ↓ capillary diameter = ↑ alveolar vascular resistance

49
Q

What would occur with alveolar capillaries during expiration?

A

↓ capillary length & ↑ capillary diameter = ↓ alveolar capillary resistance.

50
Q

What would occur with extra-alveolar vessels during inspiration?

A

↑ vessel diameter = ↓ extra-alveolar vascular resistance

51
Q

What would occur with extra-alveolar vessels during expiration?

A

↓ vessel diameter = ↑ extra-alveolar vascular resistance.

52
Q

At what volume does the lowest pulmonary vascular resistance occur?

A

Lowest PVR occurs at FRC

53
Q

At what volume does the highest pulmonary vascular resistance occur?

A

Highest PVR occurs at Residual Volume (RV)

54
Q

At what volume is alveolar volume at its greatest?

A

TLC (Total lung capacity)

55
Q

At what volume is extra-alveolar volume at its greatest?

A

RV (Residual volume)

56
Q

What general relationship do pulmonary blood flow and PVR have?

A

Inverse (ex. ↑blood flow = ↓PVR)

57
Q

Which of the following graphics below is indicative of recruitment?
Distension?

A
58
Q

How do recruitment and distension of pulmonary vasculature result in decreased PVR?

A
  • Recruitment = more parallel pathways
  • Distension = ↑ vessel diameter
59
Q

What conditions/agents/hormones/etc will cause a increase in PVR?

A
  • SNS neurotransmitters (NE, Epi, α-agonists, etc.)
  • Inflammatory mediators
  • Alveolar hypoxia
  • Alveolar hypercapnia
  • Acidotic mixed venous blood
60
Q

What inflammatory mediators will increase PVR?

A
  • Thromboxane
  • Angiotensin
  • Histamine
61
Q

What conditions/agents/hormones/etc will decrease PVR?

A
  • PSNS activity
  • ACh
  • β-agonists
  • PGE1
  • PGI2
  • Nitric Oxide
  • Bradykinin
62
Q

What effect does acetylcholine have on the lungs?

A
  • Blood vessel dilation (↓PVR)
  • Airway constriction
63
Q

What is the partial pressure of O₂ in dry atmospheric air?

A

159mmHg

O₂ pressure = 760mmHg x [.21]

64
Q

What is the formula for partial pressure?

A

Partial pressure = total pressure x [gas]

65
Q

What is the partial pressure of 100% humidity? Why does this matter?

A

47 mmHg : important due to displacing effect on other gasses.

66
Q

Calculate the partial pressure of inspired humidified O₂ .

A

PIO₂ = FIO₂ (PB - PH₂O )

PIO₂ = 0.21 (760mmHg - 47mmHg)

PIO₂ = 150 mmHg

67
Q

What would occur with intra-alveolar O₂ and CO₂ levels if a blocked airway was overcome with 100% FiO₂ and positive pressure?

A

↑O₂ & ↑CO₂ from “trapping”.

68
Q

What would normal PAO₂ be?
Why not 150mmHg as this is what’s being delivered?

A

PAO₂ = 100mmHg due to O₂ absorption into the vasculature.

69
Q

What is normal PvCO₂?
What is normal PaCO₂?

A
  • PvCO₂ = 45mmHg
  • PaCO₂ = 40mmHg
70
Q

How much CO₂ is delivered to the alveolus via the airways?
What is normal PACO₂?
Why is this?

A
  • 0 mmHg
  • 40mmHg
  • CO₂ extraction from blood vessels to alveolus for exhalation.
71
Q

If normal O₂ delivery to the tissues is 20mLO₂/dL and the normal return is 15mLO₂/dL then ΔmLO₂ = 5 mLO₂/dL.

What would the the ΔmLCO₂ be in a normal healthy person?
Why the discrepancy?

A

4.5 mLCO₂ due to increased hydrophilicity of CO₂.

72
Q

What would occur with a very negative PISF in the pulmonary interstitium?

A

Flash Pulmonary Edema

73
Q

What conditions were discussed in class that can cause pulmonary edema?
Why would each do so?

A
  • LV failure causes ↑PCAP = pulm edema
  • Colloid loss causes ↓ πCAP = pulm edema
74
Q

What does Q typically mean?

A

Blood flow (perfusion)

75
Q

What is Kf?
What is it used for?

A
  • Capillary Filtration Coefficient.
    Describes how permeable the capillaries are.
  • Kf is used to convert mmHg to blood flow.
76
Q

What is the Starling Capillary Equation?

A

Qf = Kf [(PCAP - PISF) - σ(πCAP - πISF)]

77
Q

An increase in Kf would correlate with an increase in _______ _________.

A

capillary permeability

78
Q

What is HPV (hypoxic pulmonary vasoconstriction) ?

A

Mechanism by which poorly ventilation portions of the lung are vascularly bypassed through arterial constriction.

79
Q

Where in the figure below does HPV occur?

A
80
Q

How can HPV contribute to right ventricular heart failure?

A

HPV will vasoconstrict thus increasing PVR = increased RV afterload.

81
Q

What concept is being described with the diagram in the figure below?

A

Alveolar size contrasted with blood vessel dilation/perfusion.

82
Q

Where would we expect greater air flow to occur in the diagram below? (assume an inspiration from FRC)
Why?

A

Alveoli in apex are more full, therefore air will preferentially fill the bottom portion of the lung.

83
Q

Where would we expect greater air flow to occur in the diagram below? (assume an inspiration from RV)
Why?

A

Positive PTP at the base of the lungs would cause air to preferentially fill the apex of the lung prior to the base.

84
Q

What pulmonary homeostatic mechanism prevents underutilized perfusion to underventilated arteries?

A

HPV (Hypoxic Pulmonary Vasoconstriction)

85
Q

When exercising, is it better to increase respiratory rate or depth of breathing to ensure adequate O₂ inhalation?
Why?

A

Depth of breathing: this is because VA is increased with no wasted air on VD.

86
Q

In the picture below, what is denoted by:

  • 150mls?
  • 350mls?
A
  • VD = Dead space volume = 150 mLs
  • VA = Alveolar gas volume = 350mLs
87
Q

What does n represent in our pulmonary equations?

A

n = breaths per min

88
Q

How many breaths per minute are taken under normal conditions?

A

12bpm

89
Q

What is V̇T?

A
  • T = volume of air inhaled every minute by the lungs.
  • T = (n)VT = 6L
90
Q

How can alveolar minute volume be calculated?

A

A = V̇T - V̇D

4200mLs = 6000mLs - 1800mLs

91
Q

What is VE and what is it used for?

A

VE = minute expiration volume: used to approximate V̇T

92
Q

T = _____ = VT x n

A

VE

93
Q

What percentage of TLC is RV usually?

A

20%

94
Q

At which of the following transpulmonary pressures would you expect to find the easiest to fill alveolus (at FRC)?

A. PTP = 0-10 cmH₂O
B. PTP = 10-20 cmH₂O
C. PTP = 20-30 cmH₂O
D. PTP = 30-40 cmH₂O

A

A. PTP = 0-10 cmH₂O

95
Q

Where would you expect to find a more positive PIP in the lungs?

A

Base

96
Q

Where would you expect to find a more negative PIP in the lungs?

A

Apex

97
Q

Where would you expect to find a higher PTP in the lungs?

A

Apex

98
Q

Where would you expect to find a lower PTP in the lungs?

A

Base

99
Q

Two circles are indicated below, which of these would be indicative of a higher lung compliance?

A

Green circle (steeper curve)

100
Q

Would a PTP of 30 cmH₂O be more or less compliant than a PTP of 10 cmH₂O?

A

30 cmH₂O is less compliant than 10 cmH₂O.

101
Q

Inspiration from FRC means air goes to the _____ of the lung preferentially.

A

base

102
Q

Inspiration from RV means air goes to the _____ of the lung preferentially.

A

apex/top

103
Q

Where is the intrapleural pressure located?

If you were to point to an exact space where the negative PIP is located, where is that?

A

In-between the visceral and parietal pulmonary pleura.

104
Q

How is alveolar pressure calculated?

A

PA = PIP + PER

105
Q

How is transmural pressure calculated?

A

PTP = PA - PIP

Ex. PTP = 0 - (-5) = +5