Acid-base and Blood Gases Flashcards

1
Q

What happens in an oxygen deficit?

A

Haemoglobin gives up O
Takes in CO2
HCO3- given up + exchanged for Cl-

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

What happens when its oxygen rich?

A

Large shunt of O into RBC
High affinity for O
CO2 out = gives up H+
Cl- exchanged for HCO3-

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

What happens if there is an injury in the lungs?

A

Acute problem = chest can’t respond fast = can’t get rid of gas = RBC becomes saturated

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

What normal metabolic processes are involved in the production of hydrogen?

A

Digestion of food
Metabolism of drugs
Errors with within metabolism

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

Which organ is responsible for the secretion of hydrogen?

A

Kidney

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

Why can anaerobic metabolism produce H?

A

Produces lactate = an acid = H+

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

How is CO2 produced?

A

Oxidative metabolism

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

How is CO2 excreted?

A

By ventilation

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

What is the normal pH within the body?

A

7.35-7.46

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

Describe renal filtration
1. maintain acid-base balance

A

Na+ + HCO3- filtered in glomerulus
Renal tubule cells secrete H+ in exchange for Na+
CO2 is formed by reaction of H+ + HCO3- + diffuses into tubule cell = impermeable to bicarbonate
CO2 converted back to HCO3- in cell
Na+/HCO3- symporter carries Na+ + HCO3- across membrane

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

What do renal cells do?

A

Secrete H+ in exchange for Na+

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

Describe renal filtration
2. maintain acid-base balance

A

Na+/H+ antiport secretes H+
H+ in filtrate combines with filtered HCO3- to form CO2 + H2O
CO2 diffuses into cell + combines with H2O to form H+ + HCO3-
H+ is secreted again + excreted
HCO3- is reabsorbed
Glutamine is metabolised to ammonium ion + HCO3-
NH4+ is secreted + excreted
HCO3- is reabsorbed

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

What are buffering systems in intracellular fluid?

A

Phosphate buffer system
Protein buffer

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

What are buffering systems in extracellular fluid?

A

Protein buffer
Carbonic acid-bicarbonate system

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

What is involved in protein buffering system?

A

Haemoglobin
Amino acid (all proteins)
Plasma protein

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

What is the concentration of H+:
directly proportional to?
inversely proportional to?

A

[CO2]
[HCO3-]

17
Q

What is the renal system dependent on?

A

Na+
= no sufficient Na+
= H+ can’t get out

18
Q

What is acidosis?

A

High [H+] = low pH

19
Q

What is alkalosis?

A

Low [H+] = high pH

20
Q

What is non-respiratory acidosis caused by?

A

Increased [H+] = poisons
Decreased excretion = renal failure
Decreased [HCO3-] = diarrhoea

21
Q

What are the reasons for increased [H+]?

A

Diabetic ketoacidosis = absolute lack of insulin = metabolism of fatty acids

22
Q

What are the reasons for decreased H+ excretion?

A

Decreased GFR reduces filtration of Na+ = less available to be exchanged with H = H accumulates

23
Q

Describe non-respiratory acidosis

A

H+ rises = buffered by bicarbonate
Carbonic acid produced + dissociates
Non-respiratory acidosis develops = stimulates respiratory centre to remove CO2 = producing compensatory respiratory alkalosis
= rapid breathing rate

24
Q

How do you treat non-respiratory acidosis?

A

Removal of underlying problem
BUT renal function must be maintained
Bicarbonate used in patients with pH <7

25
Q

Summary of non-respiratory acidosis

A

pH decrease
H+ increase
CO2 decrease = rapid breathing rate
HCO3- decrease = bicarbonate used to neutralise H+

26
Q

What are the causes of respiratory acidosis?

A

Airway obstruction
Depression of respiratory centre = drugs + illness
Neuromuscular disease
Pulmonary disease

27
Q

What happens in acute respiratory acidosis?

A

pH decreases
H+ increases
CO2 increases =respiratory system can’t function normally
HCO3- slight increase = some used to neutralise BUT reaction pushed right

28
Q

What happens in chronic respiratory acidosis?

A

pH slight decrease/normal
H+ slight increase/normal
CO2 increase
HCO3- increase

29
Q

What is respiratory response to metabolic change?

A

FAST

30
Q

What is metabolic response to respiratory change?

A

SLOW

31
Q

How do you treat respiratory acidosis?

A

Restore O = ventilation + high conc of O
= O prime issue = die from hypoxemia 1st

32
Q

What are the causes of non-respiratory alkalosis?

A

Excess alkali administration
Overcorrection of acidosis
Loss of free H

33
Q

How is free H lost?

A

GI loss
Mineralocorticoid steroid
Diuretic therapy

34
Q

What happens in non-respiratory alkalosis?

A

pH increases
H+ decreases
CO2 increases
HCO3- increases

35
Q

How do you treat non-respiratory alkalosis?

A

Normal saline infusion
Potassium supplements

36
Q

What causes respiratory alkalosis?

A

Hypoxia = COPD, altitude
Increased drive = infection, respiratory stimulants

37
Q

What happens in acute respiratory alkalosis?

A

pH increases
H+ decrease
CO2 decreases
HCO3- slight decrease

38
Q

What happens in chronic respiratory alkalosis?

A

pH slight increase/normal
H+ slight decrease/normal
CO2 decreases
HCO3- decreases

39
Q

What is the treatment for respiratory alkalosis?

A

Remove underlying cause
Hyperventilation = rebreathe CO2 = brown paper bag