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 83 mmHg (11.1 kPa) while the inspired oxygen is 30%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 83 mmHg (11.1 kPa)FiO₂ 30%
P/F = mmHg
2.Easy
pH7.357.457.54PaCO₂mmHg354529HCO₃⁻mmol/L222624respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.54, PaCO₂ 29 mmHg (3.9 kPa) and HCO₃⁻ 24 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.54PaCO₂ 29 mmHg (3.9 kPa)HCO₃⁻ 24 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
3.Medium

Practice values: Na⁺ 141 mmol/L, glucose 26.1 mmol/L and urea 5.5 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.

Na⁺ 141 mmol/Lglucose 26.1 mmol/Lurea 5.5 mmol/L
Osm = mOsm/kg
4.Medium

A practice gas shows PaCO₂ 21 mmHg (2.8 kPa). Use the rule that in chronic respiratory alkalosis HCO₃⁻ falls by 5 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
5.Hard

At sea level, a practice gas taken on 35% oxygen shows PaO₂ 87 mmHg (11.6 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 87 mmHg (11.6 kPa)PaCO₂ 59 mmHg (7.9 kPa)
A–a gradient = mmHg
6.Hard

Practice values: Na⁺ 140, Cl⁻ 109, HCO₃⁻ 13 mmol/L and albumin 32 g/L. Find the albumin-corrected anion gap AGc = AG + 0.25·(40 − albumin).

Na⁺ 140 mmol/LCl⁻ 109 mmol/LHCO₃⁻ 13 mmol/Lalbumin 32 g/L
AGc = mmol/L

Answer key

  1. 1. P/F = 276.7 mmHg
  2. 2. respiratory alkalosis
  3. 3. Osm = 314 mOsm/kg
  4. 4. HCO₃⁻ = 14.5 mmol/L
  5. 5. A–a gradient = 88.8 mmHg
  6. 6. AGc = 20 mmol/L

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