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
pH7.357.457.25PaCO₂mmHg354557HCO₃⁻mmol/L222624respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.25, PaCO₂ 57 mmHg (7.6 kPa) and HCO₃⁻ 24 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.25PaCO₂ 57 mmHg (7.6 kPa)HCO₃⁻ 24 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
2.Easy
pH7.357.457.27PaCO₂mmHg354541HCO₃⁻mmol/L222618respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.27, PaCO₂ 41 mmHg (5.5 kPa) and HCO₃⁻ 18 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.27PaCO₂ 41 mmHg (5.5 kPa)HCO₃⁻ 18 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
3.Medium

A practice gas shows PaCO₂ 66 mmHg (8.8 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 66 mmHg (8.8 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
4.Medium

A practice gas shows a metabolic acidosis with HCO₃⁻ 6 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.

HCO₃⁻ 6 mmol/L
PaCO₂ = mmHg
5.Hard

At sea level, a practice gas taken on 50% oxygen shows PaO₂ 89 mmHg (11.9 kPa) and PaCO₂ 50 mmHg (6.7 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 50%PaO₂ 89 mmHg (11.9 kPa)PaCO₂ 50 mmHg (6.7 kPa)
A–a gradient = mmHg
6.Hard

At sea level, a practice gas taken on 30% oxygen shows PaO₂ 87 mmHg (11.6 kPa) and PaCO₂ 47 mmHg (6.3 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 30%PaO₂ 87 mmHg (11.6 kPa)PaCO₂ 47 mmHg (6.3 kPa)
A–a gradient = mmHg

Answer key

  1. 1. respiratory acidosis
  2. 2. metabolic acidosis
  3. 3. HCO₃⁻ = 33.1 mmol/L
  4. 4. PaCO₂ = 17 mmHg
  5. 5. A–a gradient = 205 mmHg
  6. 6. A–a gradient = 68.15 mmHg

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