Arterial blood gas interpretation worksheet with answers

Free printable Arterial blood gas interpretation worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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Name: ____________________   Date: ____________

1.Easy
pH7.357.457.29PaCO₂mmHg354541HCO₃⁻mmol/L222619respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.29, PaCO₂ 41 mmHg (5.5 kPa) and HCO₃⁻ 19 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.29PaCO₂ 41 mmHg (5.5 kPa)HCO₃⁻ 19 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
2.Easy

Practice values: Na⁺ 145, K⁺ 5.0, Cl⁻ 104 and HCO₃⁻ 25 mmol/L. Calculate the anion gap AG = Na⁺ − (Cl⁻ + HCO₃⁻), without potassium.

Na⁺ 145 mmol/LK⁺ 5.0 mmol/LCl⁻ 104 mmol/LHCO₃⁻ 25 mmol/L
AG = mmol/L
3.Medium

A practice gas shows PaCO₂ 21 mmHg (2.8 kPa). Use the rule that in acute respiratory alkalosis HCO₃⁻ falls by 2 mmol/L for every 10 mmHg that PaCO₂ is below 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.

PaCO₂ 21 mmHg (2.8 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
4.Medium
pH7.357.457.52PaCO₂mmHg354552HCO₃⁻mmol/L222641uncompensatedpartially compensatedfully compensated

A practice arterial blood gas shows pH 7.52, PaCO₂ 52 mmHg (6.9 kPa) and HCO₃⁻ 41 mmol/L. The primary disorder is metabolic alkalosis. How far is it compensated? Click your answer.

pH 7.52PaCO₂ 52 mmHg (6.9 kPa)HCO₃⁻ 41 mmol/L
  1. 1uncompensated
  2. 2partially compensated
  3. 3fully compensated
5.Hard

At sea level, a practice gas taken on 24% oxygen shows PaO₂ 60 mmHg (8.0 kPa) and PaCO₂ 43 mmHg (5.7 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 24%PaO₂ 60 mmHg (8.0 kPa)PaCO₂ 43 mmHg (5.7 kPa)
A–a gradient = mmHg
6.Hard
pH7.357.457.32PaCO₂mmHg354570HCO₃⁻mmol/L222635acutechronicacute on chronic

A practice gas shows a respiratory acidosis: pH 7.32, PaCO₂ 70 mmHg (9.3 kPa), HCO₃⁻ 35 mmol/L. Use the rules ‘HCO₃⁻ rises 1 mmol/L per 10 mmHg (acute) or 3.5 mmol/L per 10 mmHg (chronic)’ to classify it. Click your answer.

pH 7.32PaCO₂ 70 mmHg (9.3 kPa)HCO₃⁻ 35 mmol/L
  1. 1acute
  2. 2chronic
  3. 3acute on chronic

Answer key

  1. 1. metabolic acidosis
  2. 2. AG = 16 mmol/L
  3. 3. HCO₃⁻ = 20.2 mmol/L
  4. 4. partially compensated
  5. 5. A–a gradient = 57.37 mmHg
  6. 6. chronic

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