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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1.Easy

A practice blood gas shows PaO₂ 78 mmHg (10.4 kPa) while the inspired oxygen is 28%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 78 mmHg (10.4 kPa)FiO₂ 28%
P/F = mmHg
2.Easy

A practice blood gas shows PaO₂ 105 mmHg (14.0 kPa) while the inspired oxygen is 70%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 105 mmHg (14.0 kPa)FiO₂ 70%
P/F = mmHg
3.Medium

Practice values: Na⁺ 146 mmol/L, glucose 17 mmol/L and urea 15.8 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.

Na⁺ 146 mmol/Lglucose 17 mmol/Lurea 15.8 mmol/L
Osm = mOsm/kg
4.Medium

A practice gas shows a metabolic acidosis with HCO₃⁻ 6 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.

HCO₃⁻ 6 mmol/L
PaCO₂ = mmHg
5.Hard

At sea level, a practice gas taken on 21% oxygen shows PaO₂ 64 mmHg (8.5 kPa) and PaCO₂ 29 mmHg (3.9 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 21%PaO₂ 64 mmHg (8.5 kPa)PaCO₂ 29 mmHg (3.9 kPa)
A–a gradient = mmHg
6.Hard

A practice gas shows a metabolic alkalosis with HCO₃⁻ 44 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.

HCO₃⁻ 44 mmol/L
PaCO₂ = mmHg

Answer key

  1. 1. P/F = 278.6 mmHg
  2. 2. P/F = 150 mmHg
  3. 3. Osm = 325 mOsm/kg
  4. 4. PaCO₂ = 17 mmHg
  5. 5. A–a gradient = 49.48 mmHg
  6. 6. PaCO₂ = 51.8 mmHg

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