A patient with chronic renal failure has tachypnea and widened QRS complexes with high blood pressure. Which acid-base imbalance should be suspected?

• A. Respiratory alkalosis
• B. Respiratory acidosis
• C. Metabolic acidosis
• D. Metabolic alkalosis

Answer: (C)

Chronic renal failure impairs the kidney’s ability to excrete acids and to generate bicarbonate, so hydrogen ions and organic acids accumulate. That drives a metabolic acidosis, lowering pH and bicarbonate levels. The body responds with rapid breathing to blow off CO2, a compensatory mechanism that shows up as tachypnea. The acidosis component also shifts potassium out of cells, leading to hyperkalemia, which can widen the QRS complexes on an ECG. All of this points to a metabolic acidosis pattern with respiratory compensation and electrolyte disturbance common in renal failure.