Lab case 414 interpretation

PH = 7.30, that is mild acidaemia.

HCO3 = 16.6 mmol/L. So, we have metabolic acidosis.

Next, we need to calculate the anion gap and the compensation for this patient.

Anion gap is calculated as: AG = Na – (Cl + HCO3) = 11.4 for this patient. This is within the acceptable normal range.

Expected respiratory compensation is calculated using Winter’s formula, that is:

Expected CO2 = 1.5 x HCO3 + 8 (+/- 2) = 32.9 (accepted range of 30.9 – 34.9 – (33-35). This patient’s pCO2 is with in the accepted range.

So far, this patient has HAGMA – (according to these calculations).

Other abnormal findings,

The most striking abnormality is lactate level of 8.4 mmol/L.This lactate level doesn’t fit with NAGMA, Whenever lactate level is more than 5 mmol/L then that patient has HAGMA. ( Hyperlactataemia more than 5 = HAGMA).

Na = 132 mmol/L, that is mild hyponatraemia.

Cl = 104 mmol/L, that is to the high side of the normal range.

Usually, Na and Cl levels move in the same direction. When we have unusually elevated Cl level compared to Na. that might reflect a sign of seriousness as a compensatory mechanism (Usually dehydration).

Creatinine level = 340 umol/L, that was acute for that patient. That support the conclusion of dehydration.

This patient actually had combined HAGMA and metabolic alcalosis.

HAGMA was due to elevated lactate level while the metabolic acidosis was due to contraction alkalosis.

His condition improved after hydration and Intravenous 5% dextrose.