Brainscape's Knowledge GenomeTM

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


See full index

ESA 5 - Integrative > Hypoxia > Flashcards

Hypoxia Flashcards

1
Q

Define hypoxia

A

Oxygen deficiency at tissue level

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

Define hypoxaemia

A

Oxygen deficiency in the blood

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

Can you have hypoxia without hypoxaemia?

A

Yes, for example cyanide poisioning

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

What is the normal range of oxygen saturation?

A

94-98%

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

What is the normal range of pO2 in the blood?

A

11.1 - 14.4 kPa

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

At what oxygen saturation is tissue damage most likely to occur?

A

<90%

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

At what pO2 is tissue damage likely to occur?

A

< 8kPa

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

What is the diagnostic criteria of respiratory failure?

A

The levels where tissue damage is most likely to occur

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

What is usually the cause of central cyanosis?

A

Usually the lungs

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

What is cyanosis?

A

A purple discolouration in the skin and mucus membranes

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

What causes the purple discolouration in cyanosis?

A

More than 5g/L deoxygenated Hb in the blood

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

Where can central cyanosis be seen?

A

In the mucosal membranes of the mouth

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

Where can peripheral cyanosis be seen?

A
  • Fingers
  • Lips
  • Toes
  • Ears
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is usually the cause of peripheral cyanosis?

A

Perfusion problems

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

What are the two key organ systems involved in hypoxia?

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

What can cause poor local (regional) perfusion?

A

Arterial narrowing or occulsion

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

Where does arterial narrowing or occlusion commonly occur?

A
  • Abdominal aorta
  • Cerebral arteries
  • Coronary arteries
  • Legs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In what conditions is there arterial narrowing or occlusion?

A
  • Peripheral vascular disease
  • Ischaemic heart disease
  • Ischaemic stroke
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What causes arterial narrowing or occlusion?

A

Atheroma or embolism

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

What are the symptoms of arterial narrowing or occlusion?

A
  • Claudication
  • Angina
  • Neurological deficit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens in atheroma?

A

A plaque completely or partially occludes the lumen, and so there is compromised flow, particularly when demand is high

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

What is the presentation of claudiation?

A

Pain on exercise, relieved by rest

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

Where is the pain in claudication felt?

A

Usually in calf, can extend to thighs/buttocks

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

What is characteristic of the pain on exercise in claudication?

A

There is usually a standard distance the person can walk, and this distance is fairly constant over time

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

What will be found on examination of a patient with claudication?

A

Weak/absent femoral pulses

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

How is claudication assessed?

A

Doppler flow

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

How is claudication treated?

A

Can normally be treated conservatively, but sometimes requires revascularisation

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

What is shock?

A

When the arterial pressure is too low to perfuse all tissues

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

What are the types of shock?

A
  • Hypovolaemic shock
  • Cardiogenic shock
  • Mechanical shock
  • Distributive shock
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the types of distributive shock?

A
  • Septic shock
  • Anaphylactic shock
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the main categories of causes of shock?

A
  • Fall in cardiac output
  • Fall in peripheral resistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What can cause a fall in cardiac output?

A
  • Loss of blood volume
  • Pump failure
  • Mechanical problems - the pump cannot fill
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Give an example of something that can cause mechanical shock

A

Tamponade

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

How does tamponade cause shock?

A

It prevents venous return from filling the heart

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

What is the result of the fall in arterial pressure in shock?

A

It causes baroreceptor mediated sympathetic reflexes - pale, cold, clammy skin and tachycardia

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

What are the categories of shock?

A
  • Hypovolaemic shock
  • Cardiogenic shock
  • Distributive shock
  • Mechanical shock
37
Q

What happens in hypovolaemic shock?

A

Loss of volume leads to low venous return, which leads to low pre-load and low cardiac output

38
Q

What can cause a loss of blood volume?

A
  • Blood loss, e.g. trauma, post-partum haemorrhage
  • ECF loss, e.g. burns, severe diarrhoea and vomiting, diabetic ketoacidosis
39
Q

What causes cardiogenic shock?

A

Damage to the myocardium, most often due to MI, means that the heart pumps too little

40
Q

What is the treatment for cardiogenic shock?

A

Revascularisation of the heart

41
Q

What are the types of distributive shock?

A
  • Septic shock
  • Anaphylactic shock
42
Q

What causes septic shock?

A

Endotoxins released by bacteria cause overwhelming vasodilation, and so a dramatic fall in TPR that the cardiac output cannot keep up with

43
Q

How do the symptoms of distributive shock differ from other types of shock?

A

You get warm, red peripheries in the early stages

44
Q

What causes anaphylactic shock?

A

The release of histamine from mast cells causes overwhelming vasodilation, leading to a dramatic fall in TPR and a drop in blood pressure

45
Q

Other than vasodilation, what do the mediators in anaphylaxis cause?

A

Bronchoconstriction and laryngeal oedema

46
Q

How is anaphylactic shock treated?

A

Adrenaline

47
Q

What is the consequence of the poor perfusion in shock?

A

The poorly perfused tissues have less oxygen reaching the tissues, and so initially use aerobic metabolism producing lactic acid, which in turn causes metabolic acidosis. Tissue then begin to die, and the prolonged ischaemia causes the release of vasodilator mediators, causing circulatory collapse and organ failure

48
Q

What can cause a poor oxygen carrying capacity?

A
  • Anaemia
  • CO poisioning
49
Q

What is anaemia?

A

Not enough haemoglobin in the blood - the patient is hypoxic, but there arterial pO2 is normal (as this is the amount dissolved in the blood)

50
Q

What happens in CO poisioning?

A

CO binds Hb, which is then unavailable for oxygen binding

51
Q

What can cause poor oxygengation of blood in lungs?

A
  • Ventilatory failure
  • Poor diffusion across alveolar membrane
  • Mismatching of ventilation and perfusion
52
Q

What pO2 of blood is classified as respiratory failure?

A

<8kPa

53
Q

What is type 1 respiratory failure?

A

Only hypoxia - pCO2 is normal or low

54
Q

What is type 2 respiratory failure?

A

Hypoxia associated with CO2 retention

55
Q

How can oxygenation be measured?

A
  • Pulse oximetry
  • Arterial blood gas analysis
56
Q

What are the advantages of pulse oximetry?

A
  • Easy to use
  • Non-invasive
57
Q

What are the disadvantages of pulse oximetry?

A

Can’t really detect under a certain point

58
Q

What are the advantages of arterial blood gas analysis?

A
  • Give exact pO2
  • Gives CO2
59
Q

What is the hallmark of hypoventilation?

A

High CO2

60
Q

What happens in ventilatory failure?

A

Not enough oxygen enters the alveoli, and not enough CO2 leaves, and so you get type 2 respiratory failure and respiratory acidosis

61
Q

What treatment does ventilatory failure normally require?

A

Artificial ventilation

62
Q

What can cause ventilatory failure?

A
  • Poor respiratory effort
  • Chest wall problems
  • Stiff lungs
  • Hard to ventilate lungs
63
Q

What can cause poor respiratory effort?

A
  • Respiratory centre depression
  • Muscle weakness
64
Q

What can cause respiratory centre depression?

A

Narcoits

65
Q

What can cause muscle weakness in the respiratory muscles?

A
  • Upper motor neurone lesions
  • Lower motor neurone lesions
66
Q

What chest wall problems can cause ventilatory failure?

A
  • Scoliosis/kyphosis
  • Trauma (flail chest)
  • Pneumothorax
67
Q

What can cause stiff lungs?

A

End stage fibrosis

68
Q

What can cause hard to ventilate lungs?

A
  • High airway resistance
  • COPD (late stages)
  • Severe asthma
69
Q

Where does chronic type 2 respiratory failure occur?

A

In COPD

70
Q

What effect does chronic COPD have on the blood cases?

A

Causes chronic hypoxia and chronic CO2 retention

71
Q

What is the result of chronic CO2 retention in COPD?

A

CSF acidity is corrected by the choroid plexus, and so central chemoreceptors are ‘reset’ to a higher CO2 level. There is persisting hypoxia, and so the respiratory drive is now driven by hypoxia via peripheral chemoreceptors

72
Q

What is the clinical relevance of the change in respiratory drive in COPD?

A

If oxygen therapy is needed, should give low concentration of oxygen with monitoring of ABGs

73
Q

How is oxygen delivery increased in chronic hypoxia?

A
  • Increased EPO leads to raised Hb
  • Increased 2,3-DPG
74
Q

What are the effects of hypoxia on pulmonary arterioles?

A

Pulmonary hypertension, leading to right heart failure and cor pulmonale

75
Q

What is affected in diffusion problems?

A

Oxygen

76
Q

Why is only oxygen affected in poor diffusion across alveolar membrane?

A

Because CO2 is more soluble

77
Q

What kind of respiratory failure is produced by poor diffusion across the alveolar membrane?

A

Type 1

78
Q

What can cause diffusion impairment across the alveolar membrane?

A
  • Fibrotic lung disease
  • Pulmonary oedema
  • Emphysema
79
Q

What is fibrotic lung disease?

A

Any disease that deposits substances in the intersticium

80
Q

How does fibrotic lung disease cause diffusion impairment?

A

The alveolar membrane is thickened, and so slows gas exchange

81
Q

How does pulmonary oedema cause diffusion impairment?

A

Fluid in interstitial space increases diffusion distance

82
Q

How does emphysema cause diffusion impairment?

A

Destruction of alveoli reduces surface area for gas exchange

83
Q

What can cause diffuse lung fibrosis?

A
  • Fibrosing alveolitis
  • Asbestosis
  • Extrinsic allergic alveolitis
  • Pneumoconiosis
84
Q

Where does ventilation-perfusion mismatch occur?

A

In disorders where some alveoli are being poorly ventilated, or some alveoli are being poorly perfused

85
Q

What is the result of ventilation-perfusion mismatch?

A

Oxygen uptake is low in affected units, and overall CO2 removal is unaffected because CO2 is easily removed by hyperventilation. Therefore, it is type 1 respiratory failure

86
Q

What can cause some alveoli to be poorly ventilated?

A
  • Pneumonia
  • Acute asthma
  • RDS of newborn
87
Q

What can cause some alveoli to be poorly perfused?

A
  • Pulmonary embolism
88
Q

How does a pulmonary embolsim cause some alveoli to be poorly perfused?

A

Blood is redirected to other parts of the lung, and ventilation of the affected parts is wasted

89
Q

Other than ventilation perfusion mismatch, what are the consequences of a massive pulmonary embolism?

A

Increased resistance in pulmonary circulation, causing acute right heart failure

ESA 5 - Integrative (10 decks)

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