Specimen Name Result Units Range
Plasma Sodium 150 mmol/L (135-145)
Potassium 2.5 mmol/L (3.5-5.5)
Chloride 59 mmol/L (100-109)
Bicarbonate 63 mmol/L (22-32)
Anion Gap 31 mmol/L (7-17)
Glucose 7.6 mmol/L (3.8-5.5)
Urea 22 mmol/L (2.7-7.2)
Creatinine 500 μmol/L (60-110)
Osmolality 312 mmol/kg (275-295)
ABG pH 7.56 (7.36-7.44)
PaO2 68 mmHg (70-100)
PaCO2 84 mmHg (35-45)

58yo male with abdominal pain and vomiting.
Gastric Outlet Obstruction
  • Hypokalaemic metabolic acidosis
  • Acute renal failure
  • Super-imposed raised AG metabolic acidosis
  • Severe vomiting >> marked loss of:
    1. HCl - hypochloraemic metabolic acidosis
    2. K+ - hypokalaemia and maintenance of alkalosis
    3. H20 - prerenal azotaemia and maintenance of alkalosis

In metabolic alkalosis:

  • PCO2 : increases 7 mmHg / 10 mmol/L rise in HCO3-
  • PCO2 : approximates last 2 digits of pH (up to 7.60)
  • pH / PCO2
    • PCO2 should be ≈ 64-72 mmHg
    • "correction" inaccurate due to underlying ARF & metabolic-acidosis