You are looking at the laboratory results of a patient admitted 2 days ago and was in metabolic acidosis because of a drug overdose. Which of the following indications compensation is occurring. pH 7.33 PaO2 85 mm Hg PaCO2 30 mm Hg HCO3 20 mEq/L 02 saturation 96%

Rationale: A. CO2 30 mm Hg is correct because respiratory compensation occurs in metabolic acidosis through hyperventilation (Kussmaul respirations), which lowers PaCO2 to help raise pH toward normal. In this patient, the HCO3 is low (20 mEq/L) indicating metabolic acidosis, and the pH is slightly acidotic (7.33). The decreased PaCO2 (normal ~35–45 mm Hg) shows the lungs are compensating by blowing off CO2 to partially correct the acidosis. B. O2 saturation 96% is incorrect because oxygen saturation reflects oxygenation, not acid-base compensation. C. PaO2 85 mm Hg is incorrect because PaO2 reflects oxygenation status in arterial blood, not the compensatory response to metabolic acidosis. D. pH 7.33 is incorrect because while the pH shows acidemia, it does not directly indicate compensation. Compensation is reflected by changes in PaCO2 or HCO3 attempting to normalize pH.