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
pH7.357.457.24PaCO₂mmHg354567HCO₃⁻mmol/L222628respiratorymetabolicacidosisalkalosis

A practice arterial blood gas shows pH 7.24, PaCO₂ 67 mmHg (8.9 kPa) and HCO₃⁻ 28 mmol/L. Which primary disorder is it? Click the cell in the grid.

pH 7.24PaCO₂ 67 mmHg (8.9 kPa)HCO₃⁻ 28 mmol/L
  1. 1respiratory acidosis
  2. 2metabolic acidosis
  3. 3respiratory alkalosis
  4. 4metabolic alkalosis
2.Easy

Practice values: Na⁺ 138, K⁺ 4.6, Cl⁻ 100 and HCO₃⁻ 23 mmol/L. Calculate the anion gap AG = Na⁺ − (Cl⁻ + HCO₃⁻), without potassium.

Na⁺ 138 mmol/LK⁺ 4.6 mmol/LCl⁻ 100 mmol/LHCO₃⁻ 23 mmol/L
AG = mmol/L
3.Medium

A practice gas shows PaCO₂ 55 mmHg (7.3 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 55 mmHg (7.3 kPa)baseline: 40 mmHg, 24 mmol/L
HCO₃⁻ = mmol/L
4.Medium

Practice values: Na⁺ 128 mmol/L, glucose 11.8 mmol/L and urea 21.6 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.

Na⁺ 128 mmol/Lglucose 11.8 mmol/Lurea 21.6 mmol/L
Osm = mOsm/kg
5.Hard
pH7.357.457.17PaCO₂mmHg354517HCO₃⁻mmol/L22266appropriate compensationadded respiratory acidosisadded respiratory alkalosis

A practice gas shows a metabolic acidosis: pH 7.17, PaCO₂ 17 mmHg (2.3 kPa), HCO₃⁻ 6 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.

pH 7.17PaCO₂ 17 mmHg (2.3 kPa)HCO₃⁻ 6 mmol/L
  1. 1appropriate compensation
  2. 2added respiratory acidosis
  3. 3added respiratory alkalosis
6.Hard

A practice gas shows a metabolic alkalosis with HCO₃⁻ 32 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.

HCO₃⁻ 32 mmol/L
PaCO₂ = mmHg

Answer key

  1. 1. respiratory acidosis
  2. 2. AG = 15 mmol/L
  3. 3. HCO₃⁻ = 25.5 mmol/L
  4. 4. Osm = 289 mOsm/kg
  5. 5. appropriate compensation
  6. 6. PaCO₂ = 43.4 mmHg

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