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

Practice values: Na⁺ 137, K⁺ 4.3, Cl⁻ 107 and HCO₃⁻ 15 mmol/L. Calculate the anion gap AG = Na⁺ − (Cl⁻ + HCO₃⁻), without potassium.

Na⁺ 137 mmol/LK⁺ 4.3 mmol/LCl⁻ 107 mmol/LHCO₃⁻ 15 mmol/L
AG = mmol/L
2.Easy
pH7.357.457.30PaCO₂mmHg354571HCO₃⁻mmol/L222634respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.30, PaCO₂ 71 mmHg (9.5 kPa) and HCO₃⁻ 34 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.30PaCO₂ 71 mmHg (9.5 kPa)HCO₃⁻ 34 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
3.Medium

Practice values: Na⁺ 131 mmol/L, glucose 28 mmol/L and urea 20.2 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.

Na⁺ 131 mmol/Lglucose 28 mmol/Lurea 20.2 mmol/L
Osm = mOsm/kg
4.Medium

A practice gas shows a metabolic acidosis with HCO₃⁻ 8 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.

HCO₃⁻ 8 mmol/L
PaCO₂ = mmHg
5.Hard

At sea level, a practice gas taken on 35% oxygen shows PaO₂ 94 mmHg (12.5 kPa) and PaCO₂ 59 mmHg (7.9 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 35%PaO₂ 94 mmHg (12.5 kPa)PaCO₂ 59 mmHg (7.9 kPa)
A–a gradient = mmHg
6.Hard

At sea level, a practice gas taken on 40% oxygen shows PaO₂ 91 mmHg (12.1 kPa) and PaCO₂ 48 mmHg (6.4 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 40%PaO₂ 91 mmHg (12.1 kPa)PaCO₂ 48 mmHg (6.4 kPa)
A–a gradient = mmHg

Answer key

  1. 1. AG = 15 mmol/L
  2. 2. respiratory acidosis
  3. 3. Osm = 310 mOsm/kg
  4. 4. PaCO₂ = 20 mmHg
  5. 5. A–a gradient = 81.8 mmHg
  6. 6. A–a gradient = 134.2 mmHg

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