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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1.Easy
pH7.357.457.31PaCO₂mmHg354539HCO₃⁻mmol/L222619respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.31, PaCO₂ 39 mmHg (5.2 kPa) and HCO₃⁻ 19 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.31PaCO₂ 39 mmHg (5.2 kPa)HCO₃⁻ 19 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
2.Easy

A practice blood gas shows PaO₂ 61 mmHg (8.1 kPa) while the inspired oxygen is 80%. Calculate the ratio P/F = PaO₂/FiO₂ in mmHg.

PaO₂ 61 mmHg (8.1 kPa)FiO₂ 80%
P/F = mmHg
3.Medium

Practice values: Na⁺ 151 mmol/L, glucose 13 mmol/L and urea 7.9 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.

Na⁺ 151 mmol/Lglucose 13 mmol/Lurea 7.9 mmol/L
Osm = mOsm/kg
4.Medium

A practice gas shows PaCO₂ 27 mmHg (3.6 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 27 mmHg (3.6 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
5.Hard
pH7.357.457.22PaCO₂mmHg354520HCO₃⁻mmol/L22268appropriate compensationadded respiratory acidosisadded respiratory alkalosis

A practice gas shows a metabolic acidosis: pH 7.22, PaCO₂ 20 mmHg (2.7 kPa), HCO₃⁻ 8 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.

pH 7.22PaCO₂ 20 mmHg (2.7 kPa)HCO₃⁻ 8 mmol/L
  1. 1appropriate compensation
  2. 2added respiratory acidosis
  3. 3added respiratory alkalosis
6.Hard

A practice gas shows a metabolic alkalosis with HCO₃⁻ 38 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.

HCO₃⁻ 38 mmol/L
PaCO₂ = mmHg

Answer key

  1. 1. metabolic acidosis
  2. 2. P/F = 76.25 mmHg
  3. 3. Osm = 323 mOsm/kg
  4. 4. HCO₃⁻ = 21.4 mmol/L
  5. 5. appropriate compensation
  6. 6. PaCO₂ = 47.6 mmHg

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