Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pathophysiology (RESP 212) > Module 3 Respiratory Mechanics > Flashcards

Module 3 Respiratory Mechanics Flashcards

1
Q

What is Tidal Volume (Vt)

A

A relaxed breath.

Normal volume of both inhalation and exhalation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Total Lung Capacity?
(TLC)

A

Volume of air in your lungs at max inhalation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is Vital Capacity (VC)?

A

Volume of air breathed out from max inhalation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is Residual Volume (RV)?

A

Air left in the lungs after exhalation

(they never fully empty or collapse when normal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Functional Residual Capacity (FRC)?

A

The volume of air left after a relaxed Vt exhalation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Inspiratory Capacity (IC)?

A

What you can inhale from FRC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Expiratory Reserve Volume (ERV)?

A

what you maximally exhale from after Vt

everything you can exhale after a normal exhale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Inspiratory Reserve Volume (IRV)?

A

What you can inhale above your Vt
(everything you can take in after a normal breath)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the min volumes required for capacities?

A

2 or more volumes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

diagram of volume capacities.

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Pressure Gradients?

A

Idk slide was blank, check later.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

when there is no air movement (Static state)? Why is it considered FRC or why does it happen?

hint consider Hooke’s Law

A

FRC occurs because lungs recoil and the thorax pulls open in the opposite direction.

2 forces balance at FRC

  • Hooke’s law + elastic recoil =
    As elastic material is pulled, the recoil force increases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Elasticity?

A

The tendency of a stretched object to return to its original shape.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are examples of elastic properties and relationships in the thorax?

Insert image of the lungs

A
  1. Elastic recoil of chest wall
    • Pleural pressure - pressure at surface of chest
  2. Elastic recoil of lung
    • Alveolar pressure - pleural pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the value for Airway opening pressure (Pao) and pleural pressure?

A

760 and 755 respectively.

note Pleural pressure is sub atmospheric;is determined from esophageal pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Do the thorax and lungs have a relationship regarding elasticity?

A

Yerp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Aside from lung/thorax interaction, What element helps keep the lungs open?

A

Surfactant.

It keeps the lungs open by decreasing surface tension. Decrease in ST prevents alveoli from sticking together so that they actually expand)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What needs to happen in the lungs to move air?

A

There needs to be a interaction with pressure, to be specific: Pressure gradients (work)

(air (fluids?) moves from high pressure to low pressure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a dynamic condition in pressure gradients?

A

When airflow is present.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are 3 types of pressure gradients?

A

Prs = Transairway/Transrespiratory pressure

PL = Transpulmonary pressure

Pw = Transthoracic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Review slides regarding Respiratory system mechanics (2 slides).

“egans: Chapter 11, pg 227”

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Lung - Thorax Pressure Gradients

What is Prs and why is it important?

A

Transairway pressure (Prs) is the difference between Alveolar pressure (PA) and ATM (Pao, pbs)

Prs = PA - Pao

This gradient is important because it causes air flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Lung Thorax Pressure Gradients:

What is PL, and what is its function?

A

Transpulmonary pressure (PL) describes the difference between Alveolar pressure (AP) and Pleural pressure (Ppl)

PL = PA - Ppl

Distending pressure across the alveolar walls

from google reps pressure that promotes air flow and distends (enlarge/swell by pressure) lungs*

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Lung - Thorax Pressure Gradients

What is Pw, and why is it important?

A

Transthoracic/ Transmural pressure (Pw) is the pressure difference between the pleural space (Ppl) and atm pressure at body surface (Pbs)

Pw - Ppl - Pbs

Pressure difference across the thoracic wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What happens when Pw increases/decreases?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is PO2?

A

Partial pressure of Oxygen

It reps the amount of oxygen gas dissolved in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why is PO2 important in abgs?

A

It primarily measures the effectiveness of the lungs in pulling oxygen into the blood stream from the atmosphere.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What formula best describes TLC?

A

TLC = RV + ERV + Vt + IRV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Equation for VC?

A

VC = ERV + Vt + IRV

measures only what you blow out.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Formula for FRC

A

RV + ERV

Residual volume and expiration reserve volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Equation for IC

A

Vt + IRV

Tidal volume and inspiratory reserve volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Expiration reserve volume (ERV)

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the difference between volume and capacity?

A

Capacities are made up of 2 or more volumes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Why do we have FRC?

A

We have FRC because lungs recoil and your thorax pulls open in the opposite direction.

2 forces balance at FRC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What aids FRC to keep the lungs open?

A

Surfactant. it keeps the lungs open by reducing surface tension.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

At FRC, what state are the lungs in?

A

Static state. there is no air flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What needs to happen in the lungs to move air?

A

Thorax needs to have a pressure gradients work to move air (work).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How do pressure gradients help lungs move air?

A

Air (fluids) move from a state of high to low pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What state is it when airflow is present

A

dynamic condition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

ATM?

A

Pao

Pressure at the airway opening of the resp system airway.

i.e mouth, nose, tracheostomy opening, tubes, etc.

41
Q

Barometric pressure?

A

Pbs

Pressure measured at the body surface.

-body surface pressure

42
Q

pleural pressure

A

Ppl

Pressure measured in the pleural space.

43
Q

how do you measure changes in pleural measure?

A

they’re estimated by measuring pressure changes in esophagus

44
Q

Alveolar Pressure

A

PA

Pressure in the alveolar (gas space) regions of the lungs

45
Q

Transairway/Tranrespiratory pressure.

what does this gradient describe and cause?

A

PRS = PA - PAO

The difference between ATM and alveolar pressure

This gradient causes air flow

46
Q

Transpulmonary pressure.

what does it describe?

A

PL = PA - Ppl

The pressure difference between alveolar pressure and pleural space

-distending pressure across alveolar walls.

47
Q

Transthoracic pressure

A

Pw = Ppl - Pbs

Pressure difference across the thoracic wall (chest wall)

48
Q

Pao/pbs

A

ATM pressure around the body

49
Q

Pao

A

pressure at airway opening

50
Q

Pbs

A

Pressure at the body surface

51
Q

PA

A

Alveolar pressure

52
Q

Ppl

A

Pressure within the pleural space

53
Q

Prs

A

Transairway/transrespiratory pressure

54
Q

PL

A

Transpulmonary pressure

55
Q

Pw

A

Transthoracic/transmural pressure

56
Q

What happens during inspiration?

A

Active contractions of ventilators muscles

-Ppl decreases
-PL (Pa-Ppl) decreases
-Pa drops below Pao (boyles law)

At end inspiration Prs = 0
-air flow ceases

57
Q

What happens to Ppl during inspiration?

A

It decreases.

Thoracic expansion (diaphragm drops) causes a increase in volume, which in turn, causes pressure to decrease

58
Q

Why is a drop below Pao related to boyles law?

A

The pressure in lungs drop below ATM and air moves into the lungs.

Pressure drops, volume (air) increases.

59
Q

What happens during exhalation

A

ventilators muscles relax and diaphragm moves back up - passive recoil forces cause lungs to shrink

PA increase
PA increases above Pao

Air flows out lungs down pressure gradient

At end expiration Prs = 0
-air flow ceases

60
Q

Exhalation: describe the PA change.

A

PA increases and lung volume decreases.

When volume decreases, there’s a increase in pressure.

61
Q

Exhalation, what does boyles law sugggest?

A

The pressure in lungs is higher than atmosphere forcing air out.

62
Q

What happens to Transthoracic pressure (Pw) during inspiration?

A

Overall, its always under negative pressure. It becomes more negative during inspiration than comes back.

63
Q

Describe thoracic pressure during inspiration?

A

When pressure increases in the thoracic cavity (inspiration), it pushes the chest wall out even more and causes a increase in pressure in the pleural space making it negative.

64
Q

What forces are needed need to be overcome so air can move in and out of the lungs?

A

Elastance
Compliance
Resistance

65
Q

Compliance (CL)

A

Measure of how easy it is to change lunge volume

Basically, How likely is something to inflate when you put pressure on it

66
Q

CL FORMULA?

A

Change in volume/ change in pressure

Normal CL = 0.2L

67
Q

What is the opposite of CL?

A

Elastance (1/elastance)

68
Q

Do ventilators change compliance numbers?

A

no.

69
Q

What does high compliance infer?

A

Lungs are easier to inflate.

ventilators don’t put enough pressure to reach tidal volume

70
Q

What does low compliance infer?

A

Lungs are harder to inflate.

Ventilators are putting in a lot of pressure to reach tidal volume

71
Q

What relation does pulmonary fibrosis have to compliance?

A

Pulmonary fibrosis causes the lungs to be stiff and thus harder to inflate

72
Q

What forces are needed to overcome for air to move in and out of the lungs?

A
  1. Elastance/Compliance
  2. Airway Resistance
73
Q

If Elastance = lung recoil force.

What does compliance (CL) imply if it is high or low?

A

Compliance = how stiff
(change in lung volume by the change in pressure, in the presence of flow.)

Increased = too pliable

Decreased = too stiff

74
Q

Dynamic vs static compliance?

A

Dynamic = compliance during breathing (airflow)

Static = compliance when airflow is absent.
(like inspiratory pause).

75
Q

Low lung elasticity requires what to change the volume of the lungs?

A

Greater than average intrapleural pressure

76
Q

High lung compliance would indicate what to change the volume of the lungs?

A

little pressure difference in intrapleural pressure.

77
Q

Lung compliance is defined as?

A

The ability of the lungs and pleural cavity to change in volume based on changes in pressure.

78
Q

Two factors that determine lung complinace?

A

Elasticity of the lung tissue and surface tension at air water interfaces

79
Q

Which lung diseases would be associated with low lung compliance?

A

Restrictive lung diseases.

Anything that makes it harder for the lungs to expand/deflate, or where gas exchange is impaired.

i.e pulmonary fibrosis.

80
Q

Which diseases would you associate with high lung compliance?

A

Obstructive diseases

i.e emphysema = destruction of elastic tissue of lungs

81
Q

Elastance/compliance is effected by?

A
  1. Elastic recoil from elastin/collagen
  2. surface tension affected by surfactant.
  3. conditions of the thorax
  4. volume in the lungs
82
Q

Resistance (Raw) is produced by frictional resistance to gas flow, where specifically would this be seen?

A

Friction between:
-gas molecules
-gas and tube walls

83
Q

2 types of flow

A

Laminar flow (less resistance)

Turbulent flow (more resistance)

84
Q

Where would you find Laminar flow?

A

smaller airways

(bronchioles and distal airspaces)

85
Q

Where would you find Turbulent flow?

A

Upper airways

(trachea and bronchi)

86
Q

Is Laminar or Turbulent flow faster?

A

Laminar is faster due to lower resistance

87
Q

Poiseuille’s law pertains to what?

V = ∆Pπ r^4 / 8Ln

A

Laminar flow

If you reduce your radius by half, you would need a 16 fold increase in pressure to maintain flow.

88
Q

Factors of Poiseuille’s law?

A

Change in pressure
Radius of the tube
Length of the tube
Viscosity of the fluid

89
Q

How to calculate resistance?

A

Resistance = change in pressure/flow rate

90
Q

How to calculate compliance?

A

Change in volume/change in pressure

91
Q

When is positive pressure and negative pressure seen in relation to mechanical ventilation?

A

Positive pressure is used to deliver a breath, whereas normal physiological breath requires negative pressure to draw air in.

92
Q

Left off at slide 58

A
93
Q

What does Poiseuille’s law depict on airways during inspiration?

A

airways are pulled open, availing wider radius within airways.

94
Q

Exhalation mechanics: what happens?

A

Airways narrow, requiring faster airflow.

95
Q

What is cephalad airflow bias?

A

When flow increases in speed because of narrowing airways.

It aids in secretion clearance.

96
Q

What is Equal pressure point (EPP)

A

Basically collapse of airways.

When airways cannot keep themselves open as a result of the pleural pressure equating with intra-airway pressure.

97
Q

What is a primary sign of concern with obstructive lung diseases like asthma or emphysema?

A

Air trapping.

98
Q

What is air trapping?

A

The inability to exhale air that is trapped secondary to resistance/compliance change.

99
Q

How to improve work of breathing (WOB)

A
  1. improve pulmonary mechanics (via meds, cpap)
  2. Take over the WOB (mechanical ventilation)

Pathophysiology (RESP 212) (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions