50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 5

 41. Which of the following laboratory findings is consistent with respiratory alkalosis?

a) pH 7.48, PCO₂ 20 mmHg, HCO₃⁻ 15 mEq/L

b) pH 7.32, PCO₂ 50 mmHg, HCO₃⁻ 28 mEq/L

c) pH 7.40, PCO₂ 40 mmHg, HCO₃⁻ 24 mEq/L

d) pH 7.30, PCO₂ 60 mmHg, HCO₃⁻ 20 mEq/L

Answer: a) pH 7.48, PCO₂ 20 mmHg, HCO₃⁻ 15 mEq/L

Explanation: Respiratory alkalosis is characterized by an elevated pH and decreased PCO₂ due to hyperventilation. The decrease in bicarbonate is a compensatory response to maintain acid-base balance.

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42. Which of the following conditions is least likely to cause metabolic acidosis?

a) Severe diarrhea

b) Renal failure

c) Aspirin overdose

d) Prolonged vomiting

Answer: d) Prolonged vomiting

Explanation: Prolonged vomiting typically leads to the loss of stomach acid (hydrochloric acid), causing metabolic alkalosis rather than metabolic acidosis. Severe diarrhea, renal failure, and aspirin overdose can cause metabolic acidosis.

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43. In a case of metabolic acidosis with a normal anion gap, which electrolyte imbalance is most commonly observed?

a) Hyperkalemia

b) Hypokalemia

c) Hyponatremia

d) Hypernatremia

Answer: a) Hyperkalemia

Explanation: In metabolic acidosis with a normal anion gap, such as in renal tubular acidosis, hyperkalemia is commonly observed due to the impaired excretion of hydrogen ions and potassium by the kidneys.

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44. Which of the following best describes the renal compensation for chronic respiratory alkalosis?

a) Increased excretion of bicarbonate

b) Increased reabsorption of bicarbonate

c) Increased secretion of hydrogen ions

d) Increased reabsorption of chloride

Answer: a) Increased excretion of bicarbonate

Explanation: In chronic respiratory alkalosis, the kidneys compensate by increasing the excretion of bicarbonate to lower the blood pH towards normal.

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45. How does an increase in arterial carbon dioxide pressure (PaCO₂) affect the acid-base balance?

a) Causes respiratory alkalosis

b) Causes metabolic alkalosis

c) Causes respiratory acidosis

d) Causes metabolic acidosis

Answer: c) Causes respiratory acidosis

Explanation: An increase in PaCO₂ indicates hypoventilation or inadequate CO₂ exhalation, leading to the accumulation of carbonic acid in the blood and resulting in respiratory acidosis.

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46. Which of the following mechanisms is most responsible for the development of lactic acidosis?

a) Excessive excretion of bicarbonate

b) Impaired renal hydrogen ion excretion

c) Tissue hypoxia leading to anaerobic metabolism

d) Overproduction of ketone bodies

Answer: c) Tissue hypoxia leading to anaerobic metabolism

Explanation: Lactic acidosis occurs when there is insufficient oxygen for aerobic metabolism, leading to anaerobic glycolysis and the accumulation of lactic acid in the blood.

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47. What is the expected compensatory response to metabolic alkalosis?

a) Increased respiratory rate

b) Decreased respiratory rate

c) Increased renal excretion of hydrogen ions

d) Decreased renal reabsorption of bicarbonate

Answer: b) Decreased respiratory rate

Explanation: In metabolic alkalosis, the body compensates by decreasing the respiratory rate to retain CO₂, which helps to increase carbonic acid levels and lower the pH towards normal.

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48. Which of the following is a common cause of mixed metabolic and respiratory acidosis?

a) Sepsis with respiratory failure

b) Anxiety with hyperventilation

c) Diabetic ketoacidosis with vomiting

d) Renal failure with hypoventilation

Answer: a) Sepsis with respiratory failure

Explanation: Sepsis can lead to metabolic acidosis due to lactic acid production, while respiratory failure can cause respiratory acidosis due to CO₂ retention, resulting in a mixed acid-base disorder.

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49. In the context of acid-base balance, what is the primary role of the kidneys in the excretion of hydrogen ions?

a) Converting CO₂ into bicarbonate

b) Excreting ammonia as a buffer

c) Reabsorbing bicarbonate from the urine

d) Producing new bicarbonate ions

Answer: d) Producing new bicarbonate ions

Explanation: The kidneys play a crucial role in acid-base balance by producing new bicarbonate ions to replace those lost in buffering hydrogen ions. This helps maintain the bicarbonate buffer system and overall pH balance.

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50. Which of the following ABG results would you expect in a patient with chronic renal failure?

a) pH 7.48, PCO₂ 32 mmHg, HCO₃⁻ 28 mEq/L

b) pH 7.30, PCO₂ 45 mmHg, HCO₃⁻ 18 mEq/L

c) pH 7.25, PCO₂ 50 mmHg, HCO₃⁻ 30 mEq/L

d) pH 7.40, PCO₂ 40 mmHg, HCO₃⁻ 24 mEq/L

Answer: b) pH 7.30, PCO₂ 45 mmHg, HCO₃⁻ 18 mEq/L

Explanation: Chronic renal failure often leads to metabolic acidosis due to the kidneys' inability to excrete hydrogen ions and produce bicarbonate, resulting in a low pH and low bicarbonate levels with a compensatory increase in PCO₂.

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 1

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 2 

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 3

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 4 

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 5