Sample Questions and Answers
Which of the following represents normal arterial blood gas (ABG) values?
pH 7.25, PaCO₂ 55 mmHg, HCO₃⁻ 30 mEq/L
B. pH 7.45, PaCO₂ 35 mmHg, HCO₃⁻ 22 mEq/L
C. pH 7.35, PaCO₂ 45 mmHg, HCO₃⁻ 28 mEq/L
D. pH 7.50, PaCO₂ 20 mmHg, HCO₃⁻ 15 mEq/L
Answer: B
A pH of 7.30, PaCO₂ of 50 mmHg, and HCO₃⁻ of 24 mEq/L indicates:
Metabolic acidosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Respiratory alkalosis
Answer: B
The term “compensated respiratory acidosis” means:
pH < 7.35, PaCO₂ ↑, HCO₃⁻ ↑
B. pH normal, PaCO₂ ↑, HCO₃⁻ ↑
C. pH > 7.45, PaCO₂ ↑, HCO₃⁻ ↓
D. pH normal, PaCO₂ ↓, HCO₃⁻ ↓
Answer: B
Which of the following can cause metabolic acidosis?
Vomiting
B. Hypoventilation
C. Diarrhea
D. Hyperventilation
Answer: C
What compensatory mechanism occurs in metabolic alkalosis?
Hyperventilation
B. Hypoventilation
C. Increased bicarbonate excretion
D. Increased bicarbonate reabsorption
Answer: B
A patient has pH 7.50, PaCO₂ 30 mmHg, and HCO₃⁻ 24 mEq/L. This is indicative of:
Respiratory acidosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Metabolic alkalosis
Answer: B
The anion gap is useful in diagnosing:
Respiratory alkalosis
B. Non-anion gap metabolic acidosis
C. High-anion gap metabolic acidosis
D. Compensated respiratory acidosis
Answer: C
A pH of 7.20, PaCO₂ 60 mmHg, and HCO₃⁻ 28 mEq/L indicates:
Uncompensated metabolic acidosis
B. Partially compensated respiratory acidosis
C. Fully compensated respiratory acidosis
D. Mixed acidosis
Answer: B
Which ABG abnormality is commonly seen in sepsis?
Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis
Answer: A
A patient with an opioid overdose is likely to present with:
Metabolic alkalosis
B. Respiratory alkalosis
C. Respiratory acidosis
D. Metabolic acidosis
Answer: C
PaO₂ levels below 60 mmHg are classified as:
Hypercapnia
B. Hypoxia
C. Hypoxemia
D. Hyperventilation
Answer: C
Which of the following represents uncompensated metabolic acidosis?
pH 7.25, PaCO₂ 35 mmHg, HCO₃⁻ 18 mEq/L
B. pH 7.36, PaCO₂ 40 mmHg, HCO₃⁻ 24 mEq/L
C. pH 7.45, PaCO₂ 25 mmHg, HCO₃⁻ 18 mEq/L
D. pH 7.30, PaCO₂ 50 mmHg, HCO₃⁻ 26 mEq/L
Answer: A
Respiratory alkalosis is commonly caused by:
Hypoventilation
B. Diabetic ketoacidosis
C. Hyperventilation
D. Kidney failure
Answer: C
A patient with chronic obstructive pulmonary disease (COPD) is most likely to have:
Respiratory alkalosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Metabolic acidosis
Answer: C
If PaCO₂ increases, what happens to the pH?
It increases
B. It decreases
C. It remains unchanged
D. It fluctuates
Answer: B
A patient with pH 7.38, PaCO₂ 48 mmHg, and HCO₃⁻ 29 mEq/L has:
Fully compensated metabolic alkalosis
B. Fully compensated respiratory acidosis
C. Mixed acidosis
D. Normal ABG
Answer: B
Hyperventilation during a panic attack results in:
Respiratory acidosis
B. Metabolic acidosis
C. Respiratory alkalosis
D. Metabolic alkalosis
Answer: C
Which electrolyte imbalance often accompanies metabolic alkalosis?
Hyperkalemia
B. Hypokalemia
C. Hypernatremia
D. Hyponatremia
Answer: B
An ABG shows pH 7.55, PaCO₂ 25 mmHg, HCO₃⁻ 24 mEq/L. The interpretation is:
Metabolic alkalosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Respiratory acidosis
Answer: B
What is the primary buffer system in the body?
Phosphate buffer system
B. Bicarbonate buffer system
C. Protein buffer system
D. Hemoglobin buffer system
Answer: B
Hypoxemia is defined as:
PaO₂ < 80 mmHg
B. PaO₂ < 60 mmHg
C. PaO₂ > 100 mmHg
D. PaO₂ < 50 mmHg
Answer: B
Diabetic ketoacidosis typically results in:
Metabolic acidosis with high anion gap
B. Metabolic alkalosis with normal anion gap
C. Respiratory acidosis
D. Respiratory alkalosis
Answer: A
Which ABG finding is most consistent with acute asthma exacerbation?
Respiratory alkalosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Mixed alkalosis
Answer: C
Prolonged vomiting results in:
Metabolic acidosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Respiratory alkalosis
Answer: C
Which compensatory mechanism is expected in respiratory acidosis?
Increased bicarbonate retention
B. Increased CO₂ excretion
C. Decreased bicarbonate reabsorption
D. Increased hydrogen ion excretion
Answer: A
The kidneys regulate pH by:
Adjusting PaO₂ levels
B. Adjusting PaCO₂ levels
C. Retaining or excreting bicarbonate
D. Retaining or excreting CO₂
Answer: C
A pH of 7.28, PaCO₂ of 55 mmHg, and HCO₃⁻ of 26 mEq/L suggests:
Respiratory acidosis
B. Metabolic acidosis
C. Mixed acidosis
D. Compensated respiratory acidosis
Answer: A
In which condition is PaCO₂ likely to decrease?
Hypoventilation
B. Pneumonia
C. Hyperventilation
D. COPD
Answer: C
Mixed metabolic acidosis and respiratory alkalosis may occur in:
Sepsis
B. Chronic renal failure
C. Diabetic ketoacidosis
D. Pulmonary embolism
Answer: A
What is the normal range for HCO₃⁻ in ABG analysis?
20-25 mEq/L
B. 22-28 mEq/L
C. 24-30 mEq/L
D. 25-35 mEq/L
Answer: B
Emily Parker –
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