Lab case 443 interpretation


PH = 6.9, that is severe acidaemia/

pCO2 = 72 mmHg. o, we have respiratory acidosis.

Usually the next step is to calculate the compensation. Usually for the respiratory compensation we expect HCO3 to increase. However. For this patient HCO3 is low.

HCO3 = 11 mmol/L. This patient has additional metabolic acidosis.

Next, we need to find to what type of metabolic acidosis this patient has. For that we need to calculate the anion gap.

Anion Gap = Na – (Cl + HCO3) = 28. So we have HAGMA.

Next we need to calculate the Delta Ratio. That is calculated as:

(AG – 12) / (24 – HCO3) = 1.2. So, we have pure HAGMA.

Other abnormal findings:

K = 3.1 mmol/L, that is mild hypokalaima. However, K level is affected by PH.

We expect K level to increase by 0.6 for every 0.1 of PH below 7.35.

Accordingly, corrected K level should be 3.1 – 2,7 = 0.4…that is extremely low.

Glucose = 12.2 mmol/L. that is hyperglycemia. Can be due to acute stress reaction.

Lactate = 17 mmol/L, that is extremely high. (Severe hyperlactataemia).

Creatinine = 126 umol/L, that is high.

Hb = 115 g/L, that is low/

So this patient has severe combined respiratory acidosis and HAGMA with associated severe hypokalaemia.

Respiratory acidosis is due to hypoventilation. That might have different reasons after car accident. Could be due to respiratory suppression, Nerve or diaphragm injuries or lung injuries.

Metabolic acidosis for this patient is caused by the severe hyperlactataemia.