Arterial Blood Gases & Acid Base Regulation Flashcards

1
Q

What should be in equilibrium with pCO2 (theoretical)?

A

Bicarbonate

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

What is FMetHb?

A

ferritin NOT ferrous in the haem- molecule that is unable to bind O2

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

What does acidosis need to correct?

A

alkalosis

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

What does hyperventilation result in?

A

increased CO2 clearance

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

What are the 4 key aspects found from an ABG?

A
  • what is the type of imbalance?
  • what is the aetiology of imbalance?
  • any homeostatic compensation?
  • oxygenation?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How to assess compensation?

A
  • both values should change
  • only one indicates it is UNcompensated
  • changes in pH suggest partial compensation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is base excess?

A

the difference between the actual bicarbonate and the expected bicarbonate

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

How do you calculate pH?

A

-log10[H+]

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

How do you calculate [H+]?

A

10^-pH

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

What is an acid?

A

any molecule that has a loosely bound H+ ion that it can donate

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

What is an base?

A

an anionic (-ive) molecule that can reversibly bind protons

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

What proportion of acid is respiratory (CO2) or metabolic (lactic, HCl…)?

A

about 95:5

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

What does alkalosis need to correct?

A

acidosis

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

What can cause a rapid compensation?

A

changes in ventilation change CO2 ventilation, altering pH

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

What can cause a slow compensation?

A

Changes in HCO3- and H+ retention/secretion in the kidneys, lead to changes in pH

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

How long does slow consumption take?

A

up to days

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

What is acidosis/alkalosis?

A

conditions that cause a change in pH

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

What is alkalaemia/acidaemia?

A

whether pH is above/below 7.35-7.45.

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

What are the different types of imbalance?

A
  • acidosis
  • alkalosis
  • normal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the different aetiologies of an imbalance?

A
  • respiratory (acidosis/alkalosis)
  • metabolic (acidosis/alkalosis)
  • mixed (respiratory and metabolic)
  • nroaml
21
Q

What are the different forms of homeostatic compensation?

A
  • uncompensated
  • partially compensated
  • fully compensated
22
Q

What are the different forms of oxygenation?

A
  • Hypoxaemia
  • Normoxaemia
  • Hyperoxaemia
23
Q

How do you differentiate between respiratory and metabolic causes?

A

look at the CO2 level

24
Q

What would indicate compensation?

A
  • changes in PaO2 and PaCO2

- changes in pH (if not normal, partial)

25
Q

What do changes in BE indicate?

A

decrease if in respiratory alkalosis - for compensation (or vice versa)

26
Q

What is a normal PaCO2?

A

4.7-6.4 kPa

27
Q

What is a normal base excess?

A

-2 - 2

28
Q

What is a normal PaO2?

A

10-13.5kPa

29
Q

What can indicated partial compensation?

A

changes in PaCO2 or BE that would help with alkalosis/acidosis but no change in pH yet

30
Q

What is seen in uncompensated respiratory acidosis?

A
  • low pH
  • high PaCO2
  • normal BE
31
Q

What is seen in partially compensated respiratory acidosis?

A
  • low pH
  • high PaCO2
  • high BE
32
Q

What is seen in fully compensated respiratory acidosis?

A
  • normal pH
  • high PaCO2
  • high BE
33
Q

What is seen in uncompensated respiratory alkalosis?

A
  • high pH
  • low PCO2
  • normal BE
34
Q

What is seen in partially compensated respiratory alkalosis?

A
  • high pH
  • low PCO2
  • low BE
35
Q

What is seen in fully compensated respiratory alkalosis?

A
  • normal pH
  • low PCO2
  • low BE
36
Q

What is seen in uncompensated metabolic acidosis?

A
  • low pH
  • normal PaCO2
  • low BE
37
Q

What is seen in partially compensated metabolic acidosis?

A
  • low pH
  • low PaCO2
  • low BE
38
Q

What is seen in fully compensated metabolic acidosis?

A
  • normal pH
  • low PaCO2
  • low BE
39
Q

What is seen in uncompensated metabolic alkalosis?

A
  • high pH
  • normal PCO2
  • high BE
40
Q

What is seen in partially compensated metabolic alkalosis?

A
  • high pH
  • high PCO2
  • high BE
41
Q

What is seen in fully compensated metabolic alkalosis?

A
  • normal pH
  • high PCO2
  • high BE
42
Q

What mechanism is used to compensate for respiratory acidosis?

A

chronic: increased HCO3- retention

43
Q

What can cause respiratory acidosis?

A

hypoventilation

44
Q

What can cause respiratory alkalosis?

A

hyperventilation

45
Q

What mechanism is used to compensate for respiratory alkalosis?

A

chronic phase: reduced HCO3- retention/reabsorption

46
Q

What can cause metabolic acidosis?

A
  • diarrhoea

- H+ gaining/HCO3- losing conditions

47
Q

What mechanism is used to compensate for metabolic acidosis?

A

hyperventilation

48
Q

What can cause metabolic alkalosis?

A
  • vomiting

- H+ losing/HCO3- gaining conditions

49
Q

What mechanism is used to compensate for metabolic alkalosis?

A

hypoventilation