ABG Basics Quiz

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1. A 68-year-old male with known COPD presents with increasing dyspnoea and drowsiness. His ABG on room air is as follows:

pH 7.28
PaCO₂ 8.0 kPa
HCO₃⁻ 28 mmol/L
PaO₂ 7.8 kPa
Base excess +3
SaO₂ 88%
Lactate 1.4 mmol/L

What is the most likely acid–base disorder? *
2. A 54-year-old female with sepsis secondary to pyelonephritis is hypotensive and tachypnoeic. Her ABG on 15L NRBM reads:

pH 7.21
PaCO₂ 4.9 kPa
HCO₃⁻ 15 mmol/L
PaO₂ 10.5 kPa
Base excess –8
SaO₂ 96%
Lactate 6.2 mmol/L

What is the most likely interpretation? *
3. A 23-year-old female presents to ED with chest tightness and paraesthesia following an anxiety episode. Her ABG on air is:

pH 7.52
PaCO₂ 3.8 kPa
HCO₃⁻ 24 mmol/L
PaO₂ 13.1 kPa
Base excess +1
SaO₂ 99%
Lactate 1.0 mmol/L

What is the acid–base disturbance? *
4. A 35-year-old male presents with profuse vomiting over 3 days. His ABG on room air is:

pH 7.48
PaCO₂ 6.1 kPa
HCO₃⁻ 30 mmol/L
PaO₂ 12.2 kPa
Base excess +6
SaO₂ 98%
Lactate 1.5 mmol/L

What is the likely acid–base diagnosis? *
5. A 27-year-old male with known type 1 diabetes presents with vomiting, abdominal pain, and lethargy. His ABG reads:

pH 7.12
PaCO₂ 3.5 kPa
HCO₃⁻ 10 mmol/L
PaO₂ 11.3 kPa
Base excess –15
SaO₂ 97%
Glucose 28 mmol/L

What is the most likely acid–base disorder? *
6. A 72-year-old female is admitted with pneumonia and hypotension. Her ABG on 4L nasal cannula reads:

pH 7.18
PaCO₂ 5.2 kPa
HCO₃⁻ 14 mmol/L
PaO₂ 9.6 kPa
Base excess –10
SaO₂ 93%
Lactate 3.8 mmol/L

What parameter indicates a red flag requiring escalation? *
7. A 65-year-old male on long-term oxygen therapy presents for routine review. ABG on 2L nasal cannula:

pH 7.35
PaCO₂ 6.5 kPa
HCO₃⁻ 30 mmol/L
PaO₂ 9.1 kPa
Base excess +4
SaO₂ 94%
Lactate 1.6 mmol/L

What is the interpretation of this ABG? *
8. A 45-year-old female with suspected PE is tachypnoeic. Her ABG on room air reads:

pH 7.49
PaCO₂ 3.6 kPa
HCO₃⁻ 22 mmol/L
PaO₂ 12.8 kPa
Base excess 0
SaO₂ 99%
Lactate 1.2 mmol/L

Which pattern best fits this gas? *
9. A 60-year-old female with congestive heart failure has the following ABG on 28% venturi:

pH 7.44
PaCO₂ 6.3 kPa
HCO₃⁻ 28 mmol/L
PaO₂ 10.9 kPa
Base excess +3
SaO₂ 95%
Lactate 1.8 mmol/L

What is the interpretation? *
10. A 78-year-old male presents with confusion and a productive cough. ABG on air:

pH 7.26
PaCO₂ 7.9 kPa
HCO₃⁻ 25 mmol/L
PaO₂ 6.8 kPa
Base excess +2
SaO₂ 85%
Lactate 2.0 mmol/L

What is the next best action? *