17. A 67-year-old female with a history of Chronic Kidney Disease is admitted to the medical unit. She reports headache, fatigue, and nausea. The nurse reviews her arterial blood gas (ABG) results:
pH: 7.25.
PaCO₂: 38 mmHg.
HCO₃⁻: 16 mEq/L.
PaO₂: 90 mmHg.
Based on the ABG findings, which of the following is the most appropriate interpretation?
Correct Answer: C. Uncompensated metabolic acidosis
Rationale:
The ABG shows low pH (acidemia), low HCO₃⁻ (indicating metabolic cause), and normal PaCO₂ (no respiratory compensation yet), consistent with uncompensated metabolic acidosis. This is common in CKD due to the kidneys’ inability to excrete hydrogen ions and regenerate bicarbonate.