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 76 mmHg (10.1 kPa) while the inspired oxygen is 70%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 76 mmHg (10.1 kPa)FiO₂ 70%
P/F = mmHg
2.Easy

A practice blood gas shows PaO₂ 85 mmHg (11.3 kPa) while the inspired oxygen is 50%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 85 mmHg (11.3 kPa)FiO₂ 50%
P/F = mmHg
3.Medium

A practice gas shows PaCO₂ 51 mmHg (6.8 kPa). Use the rule that in acute respiratory acidosis HCO₃⁻ rises by 1 mmol/L for every 10 mmHg that PaCO₂ is above 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.

PaCO₂ 51 mmHg (6.8 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
4.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
5.Hard

At sea level, a practice gas taken on 40% oxygen shows PaO₂ 89 mmHg (11.9 kPa) and PaCO₂ 29 mmHg (3.9 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 40%PaO₂ 89 mmHg (11.9 kPa)PaCO₂ 29 mmHg (3.9 kPa)
A–a gradient = mmHg
6.Hard
pH7.357.457.06PaCO₂mmHg354533HCO₃⁻mmol/L22269appropriate compensationadded respiratory acidosisadded respiratory alkalosis

A practice gas shows a metabolic acidosis: pH 7.06, PaCO₂ 33 mmHg (4.4 kPa), HCO₃⁻ 9 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.

pH 7.06PaCO₂ 33 mmHg (4.4 kPa)HCO₃⁻ 9 mmol/L
  1. 1appropriate compensation
  2. 2added respiratory acidosis
  3. 3added respiratory alkalosis

Answer key

  1. 1. P/F = 108.6 mmHg
  2. 2. P/F = 170 mmHg
  3. 3. HCO₃⁻ = 25.1 mmol/L
  4. 4. PaCO₂ = 29 mmHg
  5. 5. A–a gradient = 159.9 mmHg
  6. 6. added respiratory acidosis

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