ABGs

Question 1

Kidneys compensate in respiratory acidosis by

Answer 1

retaining Bicarbonate (HCO3) - Metabolic alkalosis

Question 2

Kidneys compensate in respiratory alkalosis by retaining

Answer 2

excreting Bicarbonate (HCO3) - Metabolic acidosis

Question 3

The lungs compensate for metabolic acidosis by

Answer 3

hypoventilating (increasing CO2) - Respiratory acidosis

Question 4

The lungs compensate for metabolic alkalosis by

Answer 4

hyperventilating (decreasing CO2) - Respiratory alkalosis

Question 5

Normal PCO2 levels

Answer 5

4.7 - 6 kPa

35 - 45 mmHg

Question 6

Normal BE levels

HCO3 levels

Answer 6

Be: (-2) - (+2) mol/L
HCO3: 22 - 26 mEq/L

Question 7

Normal pH levels

Answer 7

7.35 - 7.45

Question 8

Normal PaO2 levels

Answer 8

9.3 - 13.3 kPa

Question 9

Steps of interpreting ABGs

Answer 9

1. Look at pH = acidosis/alkalosis
2. Look at pCO2 = agrees with pH (high pCO2) = respiratory problem
3. Look at HCO3 = agrees with pH (high HCO3) = metabolic problem
4. If both pCO2 and HCO3 agree with pH = Mixed (no compensation)
5. If metabolic but pCO2 doesn’t agree = partial compensation
6. If respiratory but HCO3 doesn’t agree = partial compensation
7. If pH is normal but there is a problem + compensation = full compensation

Question 10

Very high HCO3 suggests

Answer 10

Chronic acidosis

Question 11

Low pH + High PaCO2 =

Answer 11

Respiratory Acidosis

- Respiratory opposite

Question 12

High pH + Low PaCO2 =

Answer 12

Respiratory Alkalosis

- Respiratory opposite

Question 13

Low pH + Low HCO3 =

Answer 13

Metabolic Acidosis

- Metabolic equal

Question 14

High pH + High HCO3 =

Answer 14

Metabolic Alkalosis

- Metabolic equal

Question 15

ROME stands for

Answer 15

Respiratory opposite (low pH + high PaCO2)
Metabolic equal (low pH + low HCO)

Question 16

Normal anion gap =

Answer 16

8 - 14 mmol/L

Question 17

Anion gap =

Answer 17

(Na + K) - (HCO3 + Cl)

Question 18

Low pO2 + High pCO2

Answer 18

Type 2 Respiratory Failure (non-compensated)

- CO2 retention

Question 19

Low pO2 + Normal pCO2

Answer 19

Type 1 Respiratory Failure (hypoxia without hypercapnia)

- Increased RR to maintain 02

Question 20

Type 2 Respiratory failure

Answer 20

Non-compensated

Hypoxia with hypercapnia

Question 21

Type 1 Respiratory failure

Answer 21

Compensated

Hypoxia without hypercapnia

Question 22

Causes of Type 1 respiratory failure

Answer 22

Damage to lung tissue

• Pulmonary oedema
• Pneumonia
• Pneumothorax
• Pulmonary fibrosis
• ARDS

Question 23

Causes of Type 2 respiratory failure

Answer 23

Inadequate ventilation of alveoli

• Asthma
• COPD
• Resp muscle weakness

Question 24

Anion gaps are to do with

Answer 24

Metabolic acidosis

Question 25

Causes of a normal anion gap acidosis

Answer 25

HARD AF

Hyperchloraemia 
Addinson's 
Renal tubular acidosis 
Diarrhoea 
Acetazolamide
Fistulas

Question 26

Causes of a raised anion gap acidosis

Answer 26

KUMAL

Ketones (DKA, alcohol)
Urate (renal failure)
Methanol poisoning
Aspirin poisoning (late stage)
Lactate (shock, hypoxia, sepsis)

Question 27

Causes of Respiratory Acidosis

Answer 27

Not being able to breathe properly

Pneumonia
COPD
Neuromuscular disease 
Obesity 
Pulmonary oedema 
Asthma (severe)
Opiate OD
Benzodiazepines

Question 28

Causes of Respiratory Alkalosis

Answer 28

CAPHA

CNS: Stroke, SAH, encephalitis
Anxiety (hyperventilation)
Pregnancy
High altitude
Aspiring poisoning (early stage)

Question 29

Causes of Metabolic Alkalosis

Answer 29

DANG CAP HV

Diuretics
Antacids
NG suction

Cushing’s syndrome
Congenital adrenal hyperplasia
Aspiration
Primary hyperaldosteronism

Hypokalaemia
Vomiting

Question 30

3 pillars of anaesthesia

Answer 30

Hypnosis
Analgesia
Muscle relaxation