Acid-Base Disorders — Interpretation and Diagrams

A 58-year-old man with chronic obstructive pulmonary disease (COPD) presents to the emergency department with acute exacerbation. Arterial blood gas analysis shows: pH 7.28, PaCO₂ 65 mmHg, HCO₃⁻ 28 mEq/L, PaO₂ 55 mmHg. What is the most common cause of this acid-base disturbance?

A 35-year-old man with poorly controlled diabetes presents to the emergency department with severe dyspnea, fruity-smelling breath, and altered mental status. Arterial blood gas shows pH 7.15, pCO2 28 mmHg, HCO3- 10 mEq/L, and serum electrolytes reveal Na+ 138, Cl- 102, HCO3- 10. The acid-base disorder marked **A** in the Davenport diagram is confirmed. Which of the following is the PRIMARY pathophysiologic mechanism responsible for the low bicarbonate concentration in this patient's presentation?

A 72-year-old woman with severe diarrhea for 10 days is brought to the hospital. Laboratory findings show: pH 7.32, PaCO₂ 32 mmHg, HCO₃⁻ 16 mEq/L, anion gap 10 mEq/L. What is the most common cause of the primary acid-base disturbance in this patient?

A 52-year-old man with COPD presents to the emergency department with dyspnea. Arterial blood gas analysis shows: pH 7.32, PaCO₂ 65 mmHg, HCO₃⁻ 32 mEq/L, PaO₂ 55 mmHg. Which of the following statements about this acid-base disorder is NOT true?

A 38-year-old man with COPD presents with dyspnea. ABG shows pH 7.32, PaCO₂ 58 mmHg, HCO₃⁻ 28 mEq/L. A 42-year-old woman with aspirin overdose presents with tachypnea. ABG shows pH 7.38, PaCO₂ 28 mmHg, HCO₃⁻ 16 mEq/L. Which feature best distinguishes respiratory acidosis from primary respiratory alkalosis with concurrent metabolic acidosis?