<prompt> An 8 month female baby presented with 1 day ho lethargy. She had vomited several times. Her drug addict mother said she appeared intoxicated.OE: baby was obtunded but she was easily arousable and muscle tone was normal. RR 60min. Pupils are normal. BP was 11262.Ix: Na 135 K 4.2 ,Glucose 5.9 mmoll , Cl- 116 ,Urinalysis: pH 5.0; negative for glucose ketones, positive for calcium oxalate crystals. ABG: pH 7.19, pCO2 20, PO2 100 , HCO3 6.2 ?Metabolic acidosis compensatedMetabolic acidosis paially compensatedMetabolic alkalosis compensatedMetabolic alkalosis paially compensated  <response>: Impoant points in history: Drug addict mother Tachypnea Pupils normal - no CNS depression by opioids Calcium oxalate crystal - dt ethylene glycol poisoning Ethylene glycol poisoning - leads to - acute tubular necrosis ABG: pH 7.19, pCO2 20, PO2 100 , HCO3 6.2 Calculation: Anion gap: Na - Cl- HCO3 135-1166 135-122 13 pH is 7.19 acidic.normal pH 7.35-7.45 pCO2 is 16 low that cannot explain acidotic PH normal pco2 40 HCO3 is 6.2 which is low that explain low pH. therefore acidic pH is metabolic problem.i.e.metabolic acidosis in this CASE compensation is going on which is hyperventilation leading to CO2 washout.low PCo2 since is PH is not normalised so paial compensation From ABG: metabolic acidosis paially compensated. expected PCO2 15HCO315621 actual PCO2 is almost equal to expected value this implies compensation is going fine. 