An obese 57yr male presented with a deliberate self-harm attempt of 5 days’ worth of his blister pack medications at 10pm.=
Total doses ingested shown below:
(elemental iron 105mg per tab)
Here is his venous blood gas:
|pH 7.310||Na 139 mmol/L|
|pCO2 54.7||K 5.0 mmol/L|
|pO2 34.6||Cl 106 mmol/L|
|HCO3 26.7||Creatinine 73 mmol/L|
|Glucose 6.2 mmol/L|
|Lactate 2.4 mmol/L|
GCS 14. Iron levels 14micromol/L. BSL dropped to 3.7 then 3.1 at 0200.
What is the pH?
What is the primary process?
Is there compensation?
Expected bicarb = 24 + [(pCO2 – 40)/10] if acute.
Expected bicarb = 24 + 4[(pCO2 – 40)/10] if chronic.
24 + [(pCO2 – 40)/10] = 24 + 1.47 = 25.7, slightly higher than expected HCO3.
If chronic: 24 + (4 x 1.47) = 29.88.
Are there other clues to diagnosis?
Anion gap = Na – (HCO3 + Cl):
139 – (106 + 26.7) = 6.3 = low anion gap
Obese 57yr male with respiratory acidosis following polypharmacy overdose of several CNS depressants (lorazepam, zopiclone, quetiapine, valproate).
Hypoglycaemia from sulfonylurea overdose (300mg gliclazide) + coingestants sitagliptin and metformin.
Elevated lactate from 15g metformin.
Commenced octreotide infusion at 0200, ceased at 10am and observed for 12hr post octreotide cessation. Patients must have stable BSL for minimum 12hr post cessation of octreotide infusions due to risk of prolonged hypoglycaemia.