Resp - Respiratory Mechanics Flashcards

1
Q

muscles of inspiration

A
diaphragm (75%)
external intercostals (25%)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

accessory inspiration muscles

A

scalenes (raise rib 1/2)

sternocleidomastoid (raise sternum)

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

muscles of expiration (active)

A

abdominal wall

internal intercostals

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

causes for difficulty inspiring

A

scar tissue
reduced surfactant
mucous
fluid

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

causes for difficulty expiring

A

emphysema

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

point where laminar –> turbulent

A

reynolds # > 2000

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

conditions where turbulence likely occurs

A

velocity high

radius high

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

Reynold’s number

A

Re = 2rvd/n

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

Ohm’s law (airflow)

A

F = delta P/R

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

Poiseuille’s law

A

R = 8L(viscocity)/pi(radius^4)

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

Poiseulle’s law take away

A

smaller the airway, greater the R (reduce r by 50% increase R x 16)

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

site of most airway R (+why)

A

medium sized bronchi

smaller than large (up R) and in series rather than parallel (smaller ones in parallel)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

factors increasing resistance

A
turbulent flow
small radius
lung volume decreasing
bronchial SM contraction
gas density elevated (SCUBA)
forced expiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

causes of bronchoconstriction

A

allergy
mucous, airway collapse
PNS during relaxed state (Ach on muscarinic)
low CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

causes of bronchodilation

A

SNS

  • Epi (beta-2)
  • CO2 up
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

forced exhalation

A
PA drives air out
PA = Pip + P elastic recoil
further from alveoli, less recoil
exhaling air hits R, loses P
EPP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

equal pressure point

A

when Pairway = Pip
if Pip > Pairway –> collapse
(EPP @ cartilage for healthy people)

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

emphysema and forced expiration

A

alveoli have lost elastic recoil

PA is lower, EPP happens closer to alveoli, compression of airway

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

chronic obstructive pulmonary disease (diseases)

A

asthma
chronic bronchitis
emphysema

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

emphysema mech

A
  1. irritation –> many macs, release trypsin
    usually alveoli release antitrypsin (but too many macs to fight)
  2. breakdown of alveolar walls
  3. down recoil, collapse smaller airways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

pulmonary function tests

A

spirometry
lung vol measurement
diffusion capacity for CO
arterial blood gases

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

tidal volume (TV)

A

V in or out in quiet resp

~500 ml

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

inspiratory reserve volume (IRV)

A

extra V can be inspired after quiet inspiration

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

expiratory reserve volume (ERV)

A

extra V can be expired after quiet expiration

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

inspiratory capacity (IC)

A

max V in after quiet expiration (TV + IRV)

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

vital capacity (VC)

A

max V in after max expiration (IRV + TV + ERV)

~ 4800 ml

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

residual volume (RV)

A

min air remaining in lungs after max expiration

28
Q

functional residual capacity (FRC)

A

V in lungs after quiet expiration (ERV + RV)

29
Q

total lung capacity (TLC)

A

max V lungs can hold (VC + RV) ~6000 ml

30
Q

abnormal spirometry results (obstructive)

A

can’t get air out
RV up
up RV, FRC, TLC
–> slow flow, hyperinflation, down recoil

31
Q

abnormal spirometry results (restricted)

A

cant get air in
TLC down
down VC, RV, FRC, VT
–> up recoil, down V

32
Q

spirogram measurements

A

FVC: (V forcibly blown out after full breath)
FEV1: V forced out in 1 second
FEV1/FVC: proportion

33
Q

normal FVC

A

80%

34
Q

abnormal spirogram (obstructive)

A
FEV1 down (a lot)
FVC down
FEV1/FVC down (42%)
35
Q

abnormal spirogram (restrictive)

A

FEV1 down
FVC down
FEV1/FVC normal or higher

36
Q

flow volume loop action

A
  1. inhale to TLC
  2. exhale to RV as forcefully and quickly as possible
  3. forcefully inspire to TLC
37
Q

flow volume loop: forced expiration

A

compression of airways from Pip up –> high flow then slow down
early = pt dependent
late = pt independent

38
Q

flow volume loop: forced inspiration

A

muscle force down as V up
lung recoil up as V up
airway R down as V up

39
Q

abnormal flow volume loop (obstructive)

A

scooped
peak is lower but quick
slow expiration flow

40
Q

abnormal flow volume loop (restrictive)

A

witch’s hat

TLC, FVC is lower

41
Q

Diffusion capacity action

A
  1. exhale to RV
  2. inhale gas (w/ small CO) to TLC
  3. hold breath 10 s
  4. measure exhaled gas for CO
42
Q

diffusion capacity (obstructive)

A

hyperinflation and DLCO down –> emphysema
hyperinflation and DLCO normal –> asthma
normal lung volume and DLCO normal –>. chronic bronchitis

43
Q

DLCO results

A

DLCO down in any condition affecting alveolar surface area

lung resection, emphysema

44
Q

diffusion capacity (restrictive)

A

low RV and low DLCO –> scarring diseases

normal (or high) RV and normal DLCO = neuromuscular diseases, kyphosis, scoliosis

45
Q

lung compliance

A

delta V/delta P

46
Q

things that affect compliance

A

apex vs base
inspiration vs expiration (hysteresis)
disease
amount of CT

47
Q

compliance (regional)

A

compliance greatest at base

gravity pulls on alveoli in apex, makes them more expanded

48
Q

compliance (hysteresis)

A

PV curve diff for inspiration and expiration (not linear)

scoop for inspire, bump for expire

49
Q

compliance (disease)

A

low compliance: stiff - pulmonary fibrosis - large transmural P needed to expand
high compliance: low recoil - emphysema

50
Q

elastic recoil relations

A

directly related to stiffness (low compliance)

inversely related to distensibility (high compliance)

51
Q

things affecting elastic recoil

A

elastin/collagen

*alveolar surface tension (2/3)

52
Q

surface tension actions

A

increases recoil
decreases compliance
responsible for diffs in inspiration/expiration curves

53
Q

surface tension relative to size

A

smaller alveoli more likely to collapse than larger

54
Q

LaPlace’s Law

A
P = 2T/r
T = surface tension
55
Q

DPPC

A
dipalmitoyl phosphatidylchloline
hydrophilic head (go in fluid)
hydrophobic tail (go in air)
attenuate cohesion (act as detergent)
56
Q

surfactant and alveoli size

A

most effective when DPPC close together –>

small alveoli have lower ST

57
Q

surfactant fxns

A
  1. lower surface tension (increase compliance)
  2. stabilize alveoli
  3. keep alveoli dry (avoid edema)
58
Q

how surfactant keeps alveoli dry

A

ST usually lowers interstitial hydrostatic P (pulls fluid in)
surfactant reduces this

59
Q

neonatal resp distress syndrome mech

A

abnormally low production of surfactant
up ST
collapse alveoli (atelectasis)
hypoxemia

60
Q

neonatal resp distress syndrome Sx

A

cyanosis
pronounced hysteresis
high inflation P to ventilate
pulmonary edema

61
Q

alveoli stabilizing factors

A

elastin/collagen (against overdistension)
surfactant
interdependence (tethering effect)
transmural pressure gradient

62
Q

forces promoting alveolar collapse

A

elasticity (elastin)

alveolar surface tension

63
Q

forces keeping alveoli open

A

transmural P gradient
pulmonary surfactant
alveolar interdependence

64
Q

chest volume equilibrium

A

equilibrium @ ~70% TLC
< 70: recoil force out
> 70: recoil force in

65
Q

lung/chest combined equilibrium volume

A

chest compressed below equilibrium
lung expanded above
chest force out is equal to lung force in
occurs @ FRC