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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy

A practice blood gas shows PaO₂ 69 mmHg (9.2 kPa) while the inspired oxygen is 50%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 69 mmHg (9.2 kPa)FiO₂ 50%
P/F = mmHg
2.Easy

Practice values: Na⁺ 139, K⁺ 4.7, Cl⁻ 111 and HCO₃⁻ 19 mmol/L. Calculate the anion gap AG = Na⁺ − (Cl⁻ + HCO₃⁻), without potassium.

Na⁺ 139 mmol/LK⁺ 4.7 mmol/LCl⁻ 111 mmol/LHCO₃⁻ 19 mmol/L
AG = mmol/L
3.Medium

A practice gas shows a metabolic acidosis with HCO₃⁻ 14 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.

HCO₃⁻ 14 mmol/L
PaCO₂ = mmHg
4.Medium

A practice gas shows PaCO₂ 25 mmHg (3.3 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 25 mmHg (3.3 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
5.Hard

Practice values: Na⁺ 141, Cl⁻ 108, HCO₃⁻ 13 mmol/L and albumin 15 g/L. Find the albumin-corrected anion gap AGc = AG + 0.25·(40 − albumin).

Na⁺ 141 mmol/LCl⁻ 108 mmol/LHCO₃⁻ 13 mmol/Lalbumin 15 g/L
AGc = mmol/L
6.Hard
pH7.357.457.16PaCO₂mmHg354541HCO₃⁻mmol/L222614appropriate compensationadded respiratory acidosisadded respiratory alkalosis

A practice gas shows a metabolic acidosis: pH 7.16, PaCO₂ 41 mmHg (5.5 kPa), HCO₃⁻ 14 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.

pH 7.16PaCO₂ 41 mmHg (5.5 kPa)HCO₃⁻ 14 mmol/L
  1. 1appropriate compensation
  2. 2added respiratory acidosis
  3. 3added respiratory alkalosis

Answer key

  1. 1. P/F = 138 mmHg
  2. 2. AG = 9 mmol/L
  3. 3. PaCO₂ = 29 mmHg
  4. 4. HCO₃⁻ = 16.5 mmol/L
  5. 5. AGc = 26.25 mmol/L
  6. 6. added respiratory acidosis

Full step-by-step solutions: practise this topic on examproblems.com.