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 65 mmHg (8.7 kPa) while the inspired oxygen is 24%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 65 mmHg (8.7 kPa)FiO₂ 24%
P/F = mmHg
2.Easy

A practice blood gas shows PaO₂ 108 mmHg (14.4 kPa) while the inspired oxygen is 50%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 108 mmHg (14.4 kPa)FiO₂ 50%
P/F = mmHg
3.Medium

Practice values: Na⁺ 141 mmol/L, glucose 31.9 mmol/L and urea 12.2 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.

Na⁺ 141 mmol/Lglucose 31.9 mmol/Lurea 12.2 mmol/L
Osm = mOsm/kg
4.Medium

A practice gas shows PaCO₂ 48 mmHg (6.4 kPa). Use the rule that in chronic respiratory acidosis HCO₃⁻ rises by 3.5 mmol/L for every 10 mmHg that PaCO₂ is above 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.

PaCO₂ 48 mmHg (6.4 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
5.Hard
pH7.357.457.31PaCO₂mmHg354529HCO₃⁻mmol/L222614appropriate compensationadded respiratory acidosisadded respiratory alkalosis

A practice gas shows a metabolic acidosis: pH 7.31, PaCO₂ 29 mmHg (3.9 kPa), HCO₃⁻ 14 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.

pH 7.31PaCO₂ 29 mmHg (3.9 kPa)HCO₃⁻ 14 mmol/L
  1. 1appropriate compensation
  2. 2added respiratory acidosis
  3. 3added respiratory alkalosis
6.Hard

Practice values: Na⁺ 144, Cl⁻ 112, HCO₃⁻ 18 mmol/L and albumin 23 g/L. Find the albumin-corrected anion gap AGc = AG + 0.25·(40 − albumin).

Na⁺ 144 mmol/LCl⁻ 112 mmol/LHCO₃⁻ 18 mmol/Lalbumin 23 g/L
AGc = mmol/L

Answer key

  1. 1. P/F = 270.8 mmHg
  2. 2. P/F = 216 mmHg
  3. 3. Osm = 326 mOsm/kg
  4. 4. HCO₃⁻ = 26.8 mmol/L
  5. 5. appropriate compensation
  6. 6. AGc = 18.25 mmol/L

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