45 year old woman presented to ED with unexplained confusion. Past medical history showed mild kidney impairment and chronic back pain. She has been taking regular paracetamol (1 gm QID) for the past 2 weeks for her back pain.

Her VBG shoed the following:

PH = 7.06

PaO2 = 45 mmHg

PCO2 = 22 mmHg

HCO3 = 8 mmol/L

Na = 140 mmol/L

K = 4.2 mmol/L

Cl = 98 mmol/L

Glucose = 5.6 mmol/L

Lactate = 1.6 mmol/L

Cr = 107 mmol/L

Ketones = 0.5

Questions:

• Interpret these blood gases results
• What are the potential causes
• By what mechanisms paracetamol can lead to metabolic acidosis?