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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Name: ____________________   Date: ____________

1.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
2.Easy

A practice blood gas shows PaO₂ 79 mmHg (10.5 kPa) while the inspired oxygen is 70%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 79 mmHg (10.5 kPa)FiO₂ 70%
P/F = mmHg
3.Medium
pH7.357.457.25PaCO₂mmHg354577HCO₃⁻mmol/L222633uncompensatedpartially compensatedfully compensated

A practice arterial blood gas shows pH 7.25, PaCO₂ 77 mmHg (10.3 kPa) and HCO₃⁻ 33 mmol/L. The primary disorder is respiratory acidosis. How far is it compensated? Click your answer.

pH 7.25PaCO₂ 77 mmHg (10.3 kPa)HCO₃⁻ 33 mmol/L
  1. 1uncompensated
  2. 2partially compensated
  3. 3fully compensated
4.Medium

A practice gas shows PaCO₂ 61 mmHg (8.1 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 61 mmHg (8.1 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
5.Hard
pH7.357.457.26PaCO₂mmHg354574HCO₃⁻mmol/L222632acutechronicacute on chronic

A practice gas shows a respiratory acidosis: pH 7.26, PaCO₂ 74 mmHg (9.9 kPa), HCO₃⁻ 32 mmol/L. Use the rules ‘HCO₃⁻ rises 1 mmol/L per 10 mmHg (acute) or 3.5 mmol/L per 10 mmHg (chronic)’ to classify it. Click your answer.

pH 7.26PaCO₂ 74 mmHg (9.9 kPa)HCO₃⁻ 32 mmol/L
  1. 1acute
  2. 2chronic
  3. 3acute on chronic
6.Hard

At sea level, a practice gas taken on 24% oxygen shows PaO₂ 75 mmHg (10.0 kPa) and PaCO₂ 34 mmHg (4.5 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 24%PaO₂ 75 mmHg (10.0 kPa)PaCO₂ 34 mmHg (4.5 kPa)
A–a gradient = mmHg

Answer key

  1. 1. P/F = 170 mmHg
  2. 2. P/F = 112.9 mmHg
  3. 3. partially compensated
  4. 4. HCO₃⁻ = 26.1 mmol/L
  5. 5. acute on chronic
  6. 6. A–a gradient = 53.62 mmHg

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