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
pH7.357.457.18PaCO₂mmHg354566HCO₃⁻mmol/L222624respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.18, PaCO₂ 66 mmHg (8.8 kPa) and HCO₃⁻ 24 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.18PaCO₂ 66 mmHg (8.8 kPa)HCO₃⁻ 24 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
2.Easy
pH7.357.457.55PaCO₂mmHg354540HCO₃⁻mmol/L222634respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.55, PaCO₂ 40 mmHg (5.3 kPa) and HCO₃⁻ 34 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.55PaCO₂ 40 mmHg (5.3 kPa)HCO₃⁻ 34 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
3.Medium

A practice gas shows PaCO₂ 22 mmHg (2.9 kPa). Use the rule that in acute respiratory alkalosis HCO₃⁻ falls by 2 mmol/L for every 10 mmHg that PaCO₂ is below 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.

PaCO₂ 22 mmHg (2.9 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
4.Medium

A practice gas shows PaCO₂ 49 mmHg (6.5 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 49 mmHg (6.5 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
5.Hard
pH7.357.457.13PaCO₂mmHg354531HCO₃⁻mmol/L222610appropriate compensationadded respiratory acidosisadded respiratory alkalosis

A practice gas shows a metabolic acidosis: pH 7.13, PaCO₂ 31 mmHg (4.1 kPa), HCO₃⁻ 10 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.

pH 7.13PaCO₂ 31 mmHg (4.1 kPa)HCO₃⁻ 10 mmol/L
  1. 1appropriate compensation
  2. 2added respiratory acidosis
  3. 3added respiratory alkalosis
6.Hard

At sea level, a practice gas taken on 24% oxygen shows PaO₂ 82 mmHg (10.9 kPa) and PaCO₂ 42 mmHg (5.6 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.

FiO₂ 24%PaO₂ 82 mmHg (10.9 kPa)PaCO₂ 42 mmHg (5.6 kPa)
A–a gradient = mmHg

Answer key

  1. 1. respiratory acidosis
  2. 2. metabolic alkalosis
  3. 3. HCO₃⁻ = 20.4 mmol/L
  4. 4. HCO₃⁻ = 24.9 mmol/L
  5. 5. added respiratory acidosis
  6. 6. A–a gradient = 36.62 mmHg

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