Blood Gas # 28


A 42yr female was brought to ED as a priority 1 trauma after she was found on the floor at home.  History of alcohol abuse drinking at least 2 bottles of wine per day.  GCS12 (E3 V4 M5), confused.  Bilateral raccoon eyes.

pH 7.59 Na 105 mmol/L
pCO2 45 K 2.6 mmol/L
pO2 50 Cl 49 mmol/L
HCO3 43 Creatinine 152 mmol/L
Ethanol <0.01% Glucose 6.2 mmol/L
Lactate 1.1 mmol/L

[expand title=”Interpretation”]

What is the pH?


What is the primary process?

Metabolic alkalosis.

Is there compensation?

Expected pCO2 = (0.7 x HCO3) +/- 5:

0.7 x 43 = 30.1 +/- 5

Higher than expected pCO2.  Coexisting respiratory acidosis.


Are there other clues to diagnosis?

Anion gap = Na – (HCO3 + Cl): 

105 – 92 = 13

Negative delta gap due to profound alkalosis.


Electrolyte clues:

Profound hyponatraemia, hypokalaemia, hypochloraemia.

Renal impairment.



Profound metabolic alkalosis: Causes of metabolic alkalosis : CLEVERRR

(Contraction, Licorice, Endocrine, Vomiting, Excess alkalis, Refeeding alkalosis, Renal Retention of bicarb).

Coexisting resp acidosis from altered mental state, drowsy and hypoventilation.

Needs to assess urine and serum osmolality and electrolytes.

Case Resolution:

Patient was admitted to ICU.  Slow correction of hyponatraemia.  Correction of hypokalaemia.  Patient had CT abdo due to lipase 1160 in the context of “fall” and “trauma”.  Noted to have SBO / ileus.  General surgical consultation and dietitian input.  Slow initiation of enteral feeds.  Monitored for refeeding syndrome.  Phos was 1.23, Mag 0.98.


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