pH is 7.2; PCO2 12; PO2 55 most likely cause is -

In this patient pH → Decreased (Normal 7.4) PCO2 → Decreased. First step Determine whether it is acidosis or alkalosis. The decrease in pH suggests acidosis. Second step Observed HCO3-/PCO2 to determine the cause of acidosis or alkalosis Only one value is mentioned and that too is not in sync with the pH PCO2 value of 12 indicates respiratory alkalosis But the pH of the serum indicates acidosis, this suggests the presence of some other disorder besides the respiratory alkalosis which must be producing acidosis Option 'a' appears to be appropriate because the coexisting metabolic acidosis will cause a decrease in pH.