PH = 6.782, that is severe acidaemia.

HCO3 = 2.5 mmol/L, that is extremely low. So we have metabolic acidosis.

Next we need to calculate the compensation and find out what type of metabolic acidosis this patient has.

To calculate the compensation we use Winter’s formula. That is:

Expected CO2 = 1.5 x HCO3 + 8 (+/-2).

Accordingly, expected pCO2 for this patient is: 1.5 x 2.5 + 8 = 11.75 (We will say 12 mmHg). with expected range of 10 mmHg to 14 mmHg.

This patient’s pCO2 is 17 mmHg, so we have additional mild respiratory acidosis. (However, this sample is venous.  pCO2 is usually slightly higher in venous blood. Normal value of pCO2 is 40 mmHg in arterial blood and 48 mmHg in venous blood).

Next we will calculate the anion gap to find out what type of acidosis this patient has. Anion gap (AG) is calculated as Na – (Cl + HCO3) = 37.5, that is extremely high. So this patient has HAGMA.

Next, we need to calculate delta ratio to find out if there is an additional metabolic process. Delta ratio is calculated as:

Delta ratio = (AG – 12) / (24 – HCO3) = 1.18, so we have pure HAGMA.

Other abnormal findings:

K = 6.5, that is moderate hyperkalaemia. However, serum K level is usually elevated in the presence of acidosis due to transcellular electrolytes shift.

K level will increase by 0.6 mmol for every 0.1 PH below 7.4. Accordingly, corrected K level will be.  6.5 – (0.6 x6) = 2.9 mmol/L.

Lactate level = 19 mmol/L. This level is extremely high. Whenever the lactate level is very high (>7) we need to consider type – B (Non-hypoxic) hyperlactataemia.

Glucose = 13.2 mmol/L that is hyperglycaemia

Cr = 1191 umol/L that is extremely high. In region of ESRF.

this patient developed renal failure secondary to dehydration. Renal failure affected Metformin excretion. Metformin build up leads to mitochondrial dysfunction/failure and this leads to lactic acidosis.

Treatment is urgent dialysis to get rid of metformin.