QuestionSBA
QuestionChoice
Remember ROME

Resp = Opposite

eg. low pH + high pco2 = acidosis OR high pH + low pco2 = alkalosis

Metabolic = Equal

eg. low pH + low bicarb = acidosis OR high pH + high bicarb = alkalosis

This patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis. This option is therefore incorrect.
10007034
d
Metabolic alkalosis
QuestionChoice
There is a 5 step process to interpreting ABGs:

1) How is the patient? (Clinical judgement is needed here but as preclinical medics it is still simple to interpret ABGs)

2) Is the patient hypoxaemic? The pO2 on air should be >10 kPa

3) Is the patient acidaemic (pH <7.35) or are they alkalaemic (pH >7.45)? This tells you whether this is an acidosis or alkalosis.

To ascertain metabolic or respiratory causes, steps 4 and 5 are key.

4) Respiratory - pCO2 reading. >6.0 kPa suggests respiratory acidosis (or compensating for metabolic alkalosis). <4.7kPa suggests respiratory alkalosis (or compensating for metabolic alkalosis).

5) Metabolic - bicarbonate reading. <22 mmol/L suggests metabolic acidosis (or compensating for respiratory alkalosis). >26 mmol/L suggests metabolic alkalosis (or compensating for respiratory acidosis).

This patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis.
10007031
a
Respiratory acidosis
QuestionChoice
Remember ROME

Resp = Opposite

eg. low pH + high pco2 = acidosis OR high pH + low pco2 = alkalosis

Metabolic = Equal

eg. low pH + low bicarb = acidosis OR high pH + high bicarb = alkalosis

This patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis. This option is therefore incorrect.
10007033
c
Metabolic acidosis
QuestionChoice
Remember ROME

Resp = Opposite

eg. low pH + high pco2 = acidosis OR high pH + low pco2 = alkalosis

Metabolic = Equal

eg. low pH + low bicarb = acidosis OR high pH + high bicarb = alkalosis

This patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis. This option is therefore incorrect.
10007032
b
Respiratory alkalosis
QuestionChoice
Remember ROME

Resp = Opposite

eg. low pH + high pco2 = acidosis OR high pH + low pco2 = alkalosis

Metabolic = Equal

eg. low pH + low bicarb = acidosis OR high pH + high bicarb = alkalosis

This indicates a normal anion gap, as seen in diarrhoea, addison's and gastrointestinal causes of bicarbonate loss.

The patient demonstrates a low pH and raised pCO2, in keeping with a respiratory acidosis. This option is therefore incorrect.
10007035
e
Hyperchloraemic metabolic acidosis
Concept
Chapter
2693
4485
Acid-Base Balance and the Arterial Blood Gas
Topic
150
Respiratory physiology
13953
A 41-year-old man presents to A&E feeling extremely unwell. An arterial blood gas is taken, which shows:


||||
|--------------|:-------:|------------------|
|pH|7.33|7.35 - 7.45|
|PaO₂|9.6 kPa|11 - 15|
|PaCO₂|6.7 kPa|4.6 - 6.4|
|Bicarbonate|32 mmol/L|22 - 30|

Which of the following correctly describes the acid-base imbalance?
a