A 33 year old female has gram negative  bacteraemia  and septic shock. The following are data from blood gas analysis.

Test

Value

Normal Range

Barometric pressure

760 mmHg (100 kPa)

FiO2

0.3

pH

7.43

7.35 – 7.45

pCO2*

23 mmHg (3.1 kPa)

35 – 45  (4.6 – 5.9)

pO2

107 mmHg (14.3 kPa)

80 – 110  (10.5 – 14.5)

Bicarbonate*

15 mmol/L

24 – 32

Standard Base Excess*

-8.6 mmol/L

-2.0 – +2.0

Lactate*

23.0 mmol/L

0.2 – 2.5

Sodium*

147 mmol/L

137 – 145

Potassium*

6.7 mmol/L

3.2 – 4.5

Chloride*

95 mmol/L

100 – 110

a)  List the acid-base abnormalities.

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College Answer

a)  List the acid-base abnormalities.
Lactic acidosis
Anion gap elevation (37 mEq/L) Metabolic alkalosis
Respiratory alkalosis

Discussion

This question is frequently repeated. A list of duplicates can be found in a chapter on the causes of lactic acidosis in sepsis. Question 6.4 from the first paper of 2013 contains a detailed discussion of the answer.