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
pH7.357.457.53PaCO₂mmHg354530HCO₃⁻mmol/L222624respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.53, PaCO₂ 30 mmHg (4.0 kPa) and HCO₃⁻ 24 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.53PaCO₂ 30 mmHg (4.0 kPa)HCO₃⁻ 24 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
2.Easy

A practice blood gas shows PaO₂ 98 mmHg (13.1 kPa) while the inspired oxygen is 30%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 98 mmHg (13.1 kPa)FiO₂ 30%
P/F = mmHg
3.Medium
pH7.357.457.36PaCO₂mmHg354533HCO₃⁻mmol/L222618uncompensatedpartially compensatedfully compensated

A practice arterial blood gas shows pH 7.36, PaCO₂ 33 mmHg (4.4 kPa) and HCO₃⁻ 18 mmol/L. The primary disorder is metabolic acidosis. How far is it compensated? Click your answer.

pH 7.36PaCO₂ 33 mmHg (4.4 kPa)HCO₃⁻ 18 mmol/L
  1. 1uncompensated
  2. 2partially compensated
  3. 3fully compensated
4.Medium

A practice gas shows PaCO₂ 20 mmHg (2.7 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 20 mmHg (2.7 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
5.Hard

A practice gas shows a metabolic alkalosis with HCO₃⁻ 31 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.

HCO₃⁻ 31 mmol/L
PaCO₂ = mmHg
6.Hard

At sea level, a practice gas taken on 21% oxygen shows PaO₂ 73 mmHg (9.7 kPa) and PaCO₂ 50 mmHg (6.7 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 21%PaO₂ 73 mmHg (9.7 kPa)PaCO₂ 50 mmHg (6.7 kPa)
A–a gradient = mmHg

Answer key

  1. 1. respiratory alkalosis
  2. 2. P/F = 326.7 mmHg
  3. 3. fully compensated
  4. 4. HCO₃⁻ = 14 mmol/L
  5. 5. PaCO₂ = 42.7 mmHg
  6. 6. A–a gradient = 14.23 mmHg

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