QuestionSBA
QuestionChoice
This is incorrect; this ABG shows a metabolic alkalosis. This is indicated by the high pH value and the fact that the bicarbonate is high.
10025939
e
pH- 7.51, PaO2-12.0kPa, PaCO2- 6.1kPa, HCO3-35mmol/L
QuestionChoice
This is incorrect; this ABG shows respiratory **alkalosis** rather than acidosis. This is indicated by the alkaline (raised) pH and the low carbon dioxide.
10025936
b
pH- 7.48, PaO2-12.0kPa, PaCO2- 3.8kPa, HCO3-22mmol/L
QuestionChoice
This is incorrect; this ABG is normal.
10025937
c
pH- 7.36, PaO2-14.0kPa, PaCO2- 6.2kPa, HCO3-25mmol/L
QuestionChoice
This is incorrect. Whilst this ABG does show acidosis, this appears to have a metabolic rather than respiratory cause. This is indicated by a low/normal CO2 and a low bicarbonate. The low bicarbonate level indicates that more bicarbonate is being used to react with hydrogen ions to make carbonic acid, which makes the blood more acidic. The carbon dioxide being low/normal suggests the respiratory system is beginning to compensate for this decrease in pH by expelling more (acidic) CO2.
10025938
d
pH- 7.3, PaO2-12.0kPa, PaCO2- 4.5kPa, HCO3-14mmol/L
QuestionChoice
This is correct; these ABG results are in keeping with respiratory acidosis. Note there is a low pH, demonstrating acidosis, coupled with a high PaCO2, which indicates a respiratory cause. The slightly raised bicarbonate level also indicates some metabolic compensation. This in turn suggests a more chronic respiratory acidosis.
10025935
a
pH- 7.3, PaO2-10.5kPa, PaCO2- 7.0kPa, HCO3-32mmol/L
Concept
Chapter
2693
4015
Causes of respiratory acidosis
Topic
170
Clinical Chemistry
17585
A 45 year old man attends A&E with acute shortness of breath. He has been feeling generally unwell for the past 5 days, with a cough productive of green sputum. He is a long-term smoker with a known diagnosis of COPD. An arterial blood gas (ABG) is performed.

Which of the following ABG results are in keeping with respiratory acidosis?
a