Below is the interpretation for Lab Case 1
45M, AMS
room air
pH 6.9 – severe acidaemia
HCO3 4.0
BE < -30 severe metabolic acidosis
1. compensation
expected pCO2 = 1.5XHCO3 + 8 = 14
actual CO2 = 21 poorly compensated, additional resp acidosis
2. Anion Gap = 40 very high
causes – CATMUDPILES
3. Osmolar gap
calculated osmolality (show calculation 2Na+U+glucose) = 316.7
osmolar gap = 28.7 high => causes – likely toxic alcohol ingestion (ethanol low)
4. normal CO, glucose, urea, Cl
5. K normal but corrected for pH = severe total body depletion requires careful monitoring and replacement (will decrease quickly as acidosis resolves)
6. mod – severe hyperNa – N/Saline resuscitation
7. A-a gradient
(760-47)X0.21 = 150 – 1.25X20 = 125
gradient = 125 -115 = 10 (normal)
8. pO2 115 – high, appropriate for hyperventilation on room air
Interpretation
45 year with life threatening HAGMA, elevated osmolar gap and total body depletion of K. Likely due to toxic alcohol ingestion. Requires immediate resuscitation, temporizing with ethanol, (ivi – AMS), temporizing HCO3 if intubation required (apnoea will worsen acidosis), urgent toxicology and ICU consultation for haemodialysis.
Read up on methanol and ethylene glycol toxicity