Go Back to QBank Table of Contents
10. A healthy 22-year-old man ascends to high altitude. After 48 hours, which of the following changes is most likely seen?
| Parameter | Change |
|---|---|
| pO₂ | ↓ |
| pCO₂ | ↓ |
| HCO₃⁻ | ↓ |
| Ventilation rate | ↑ |
A. Respiratory acidosis with renal compensation
B. Metabolic alkalosis with respiratory compensation
C. Respiratory alkalosis with renal compensation
D. Mixed respiratory and metabolic alkalosis
✅ Correct Answer: C
9. A 60-year-old man with COPD presents with worsening shortness of breath. ABG shows elevated pCO₂ and HCO₃⁻. Which of the following patterns is most likely?
| Parameter | Change |
|---|---|
| pCO₂ | ↑ |
| HCO₃⁻ | ↑ |
| pH | ~ |
A. Acute respiratory acidosis
B. Chronic respiratory acidosis with renal compensation
C. Metabolic acidosis
D. Respiratory alkalosis
✅ Correct Answer: B
8. A 35-year-old woman with anxiety has an episode of hyperventilation. What changes are expected?
| Parameter | Change |
|---|---|
| pCO₂ | ↓ |
| pH | ↑ |
| HCO₃⁻ | ~ |
A. Acute respiratory alkalosis
B. Chronic respiratory alkalosis
C. Metabolic acidosis
D. Mixed disorder
✅ Correct Answer: A
7. A patient develops diarrhea for 3 days. Which of the following changes is expected?
| Parameter | Change |
|---|---|
| HCO₃⁻ | ↓ |
| pH | ↓ |
| pCO₂ | ↓ |
| Anion gap | Normal |
A. Metabolic alkalosis
B. High anion gap metabolic acidosis
C. Non-anion gap metabolic acidosis
D. Respiratory alkalosis
✅ Correct Answer: C
6. A 28-year-old man is given a loop diuretic. What are the expected changes?
| Parameter | Change |
|---|---|
| H⁺ | ↓ |
| HCO₃⁻ | ↑ |
| K⁺ | ↓ |
| Aldosterone | ↑ |
A. Metabolic alkalosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Mixed disorder
✅ Correct Answer: A
5. A patient has uncontrolled diabetes mellitus and presents in DKA. Labs show:
| Parameter | Change |
|---|---|
| Glucose | ↑ |
| H⁺ | ↑ |
| HCO₃⁻ | ↓ |
| K⁺ (serum) | ↑ |
A. Metabolic alkalosis with hypokalemia
B. High anion gap metabolic acidosis with hyperkalemia
C. Respiratory alkalosis
D. Non-anion gap metabolic acidosis
✅ Correct Answer: B
4. A 65-year-old woman with renal failure shows the following labs:
| Parameter | Change |
|---|---|
| H⁺ | ↑ |
| HCO₃⁻ | ↓ |
| K⁺ | ↑ |
| pH | ↓ |
A. Respiratory acidosis
B. Non-anion gap metabolic acidosis
C. High anion gap metabolic acidosis
D. Metabolic alkalosis
✅ Correct Answer: C
3. A patient is found to have a pulmonary embolism. What immediate changes are expected?
| Parameter | Change |
|---|---|
| pO₂ | ↓ |
| pCO₂ | ↓ |
| pH | ↑ |
A. Respiratory alkalosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Normal ABG
✅ Correct Answer: A
2. A man is infused with a large amount of isotonic saline. What changes are expected?
| Parameter | Change |
|---|---|
| ECF volume | ↑ |
| ADH | ↓ |
| Aldosterone | ↓ |
| Serum Na⁺ | ~ |
A. Volume depletion with hyponatremia
B. Volume overload with hypernatremia
C. Isotonic volume expansion
D. Hypovolemic hyponatremia
✅ Correct Answer: C
1. A 25-year-old woman has been vomiting repeatedly for the past 2 days due to a gastrointestinal illness. Physical examination reveals dry mucous membranes and mild hypotension. Laboratory studies show the following changes:
| Parameter | Change |
|---|---|
| H⁺ (Hydrogen ion) | ↓ |
| HCO₃⁻ | ↑ |
| pCO₂ | ↑ |
| K⁺ (Potassium) | ↓ |
Which of the following best explains these findings?
A. Metabolic acidosis with respiratory compensation
B. Respiratory alkalosis with renal compensation
C. Metabolic alkalosis with respiratory compensation
D. Respiratory acidosis with renal compensation
Correct Answer: C. Metabolic alkalosis with respiratory compensation
Explanation:
- Vomiting leads to loss of gastric acid → metabolic alkalosis (↓ H⁺, ↑ HCO₃⁻).
- The body compensates by hypoventilation, leading to ↑ pCO₂.
- Hypokalemia (↓ K⁺) is common due to loss of K⁺ in vomit and secondary aldosterone effects.
Simon Downes, MD, PhD 