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MDC III Exam 1 (Rasmussen) — 100 Practice Questions with Answers (English)
Section 1: Acid-Base Balance (Questions 1–15)
1. A patient with a 3-day history of severe diarrhea is brought to the ED. ABG results: pH
7.30, PaCO₂ 35 mm Hg, HCO₃ 16 mEq/L. What is the acid-base disorder?
A) Respiratory acidosis
B) Metabolic acidosis
C) Metabolic alkalosis
D) Respiratory alkalosis
Answer: B
This patient has metabolic acidosis from loss of bicarbonate through diarrhea. pH is low
(acidemia), HCO₃ is below normal (22–26 mEq/L), indicating a primary metabolic process .
2. A patient with COPD presents with confusion and lethargy. ABG: pH 7.25, PaCO₂ 70 mm
Hg, HCO₃ 30 mEq/L. What is the interpretation?
A) Acute respiratory acidosis with full renal compensation
B) Chronic respiratory acidosis with full renal compensation
C) Acute respiratory alkalosis
D) Metabolic alkalosis with respiratory compensation
Answer: B
This is chronic respiratory acidosis with full renal compensation. The elevated HCO₃ (30)
indicates the kidneys have retained bicarbonate to buffer the acidosis, a process that takes
24–48 hours .
3. A patient is intubated and on a ventilator. The nurse notes the patient is fighting the
ventilator, with high pressure alarms. ABG shows pH 7.58, PaCO₂ 22, HCO₃ 24. What is the
likely cause?
A) Improper tube placement (mainstem bronchus)
B) Patient-ventilator asynchrony leading to hyperventilation
C) Mucus plug causing decreased compliance
D) Pneumothorax
Answer: B
The ABG shows severe respiratory alkalosis (high pH, low PaCO₂). Patient-ventilator
asynchrony causes hyperventilation. Intervention includes sedation, analgesia, or adjusting
ventilator settings .
4. A diabetic patient has been vomiting for 2 days. ABG: pH 7.31, PaCO₂ 55, HCO₃ 22.
Which acid-base disorder is present?
, 2
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Answer: A
Vomiting causes loss of gastric acid (HCl), but the ABG shows acidemia with a normal-ish
HCO₃. The elevated PaCO₂ suggests respiratory compensation is not fully effective. The
primary process is metabolic acidosis from dehydration and ketosis in a diabetic patient .
5. What are the normal ABG values?
A) pH 7.35–7.45, PaCO₂ 35–45, HCO₃ 22–26
B) pH 7.25–7.35, PaCO₂ 45–55, HCO₃ 18–22
C) pH 7.45–7.55, PaCO₂ 25–35, HCO₃ 26–30
D) pH 7.30–7.40, PaCO₂ 40–50, HCO₃ 20–28
Answer: A
Normal ABG values: pH 7.35–7.45, PaCO₂ 35–45 mm Hg, HCO₃ 22–26 mEq/L .
6. A patient with metabolic alkalosis would have which ABG values?
A) High pH, high HCO₃
B) Low pH, low HCO₃
C) High pH, low CO₂
D) Low pH, high CO₂
Answer: A
Metabolic alkalosis presents with high pH and high HCO₃ .
7. Respiratory alkalosis is characterized by:
A) High pH, low CO₂
B) Low pH, high CO₂
C) High pH, high HCO₃
D) Low pH, low HCO₃
Answer: A
Respiratory alkalosis: high pH, low CO₂ (hyperventilation) .
8. A patient with renal failure is likely to develop which acid-base imbalance?
A) Respiratory alkalosis
B) Metabolic acidosis
C) Metabolic alkalosis
D) Respiratory acidosis
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Answer: B
Renal failure impairs excretion of hydrogen ions and reabsorption of bicarbonate, leading to
metabolic acidosis .
9. A patient with prolonged vomiting is at risk for:
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Answer: B
Vomiting causes loss of gastric acid (HCl), leading to metabolic alkalosis .
10. A patient with anxiety and hyperventilation is likely to develop:
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Answer: D
Hyperventilation causes excessive loss of CO₂, leading to respiratory alkalosis.
11. What is the primary compensation for metabolic acidosis?
A) Kidneys retain bicarbonate
B) Lungs increase ventilation to blow off CO₂
C) Lungs decrease ventilation to retain CO₂
D) Kidneys excrete bicarbonate
Answer: B
The lungs compensate for metabolic acidosis by increasing ventilation to blow off CO₂
(Kussmaul respirations).
12. What is the primary compensation for respiratory acidosis?
A) Lungs increase ventilation
B) Kidneys retain bicarbonate
C) Kidneys excrete bicarbonate
D) Lungs decrease ventilation
Answer: B
The kidneys compensate for respiratory acidosis by retaining bicarbonate (takes 24–48
hours).
13. A patient with salicylate (aspirin) poisoning is likely to develop:
MDC III Exam 1 (Rasmussen) — 100 Practice Questions with Answers (English)
Section 1: Acid-Base Balance (Questions 1–15)
1. A patient with a 3-day history of severe diarrhea is brought to the ED. ABG results: pH
7.30, PaCO₂ 35 mm Hg, HCO₃ 16 mEq/L. What is the acid-base disorder?
A) Respiratory acidosis
B) Metabolic acidosis
C) Metabolic alkalosis
D) Respiratory alkalosis
Answer: B
This patient has metabolic acidosis from loss of bicarbonate through diarrhea. pH is low
(acidemia), HCO₃ is below normal (22–26 mEq/L), indicating a primary metabolic process .
2. A patient with COPD presents with confusion and lethargy. ABG: pH 7.25, PaCO₂ 70 mm
Hg, HCO₃ 30 mEq/L. What is the interpretation?
A) Acute respiratory acidosis with full renal compensation
B) Chronic respiratory acidosis with full renal compensation
C) Acute respiratory alkalosis
D) Metabolic alkalosis with respiratory compensation
Answer: B
This is chronic respiratory acidosis with full renal compensation. The elevated HCO₃ (30)
indicates the kidneys have retained bicarbonate to buffer the acidosis, a process that takes
24–48 hours .
3. A patient is intubated and on a ventilator. The nurse notes the patient is fighting the
ventilator, with high pressure alarms. ABG shows pH 7.58, PaCO₂ 22, HCO₃ 24. What is the
likely cause?
A) Improper tube placement (mainstem bronchus)
B) Patient-ventilator asynchrony leading to hyperventilation
C) Mucus plug causing decreased compliance
D) Pneumothorax
Answer: B
The ABG shows severe respiratory alkalosis (high pH, low PaCO₂). Patient-ventilator
asynchrony causes hyperventilation. Intervention includes sedation, analgesia, or adjusting
ventilator settings .
4. A diabetic patient has been vomiting for 2 days. ABG: pH 7.31, PaCO₂ 55, HCO₃ 22.
Which acid-base disorder is present?
, 2
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Answer: A
Vomiting causes loss of gastric acid (HCl), but the ABG shows acidemia with a normal-ish
HCO₃. The elevated PaCO₂ suggests respiratory compensation is not fully effective. The
primary process is metabolic acidosis from dehydration and ketosis in a diabetic patient .
5. What are the normal ABG values?
A) pH 7.35–7.45, PaCO₂ 35–45, HCO₃ 22–26
B) pH 7.25–7.35, PaCO₂ 45–55, HCO₃ 18–22
C) pH 7.45–7.55, PaCO₂ 25–35, HCO₃ 26–30
D) pH 7.30–7.40, PaCO₂ 40–50, HCO₃ 20–28
Answer: A
Normal ABG values: pH 7.35–7.45, PaCO₂ 35–45 mm Hg, HCO₃ 22–26 mEq/L .
6. A patient with metabolic alkalosis would have which ABG values?
A) High pH, high HCO₃
B) Low pH, low HCO₃
C) High pH, low CO₂
D) Low pH, high CO₂
Answer: A
Metabolic alkalosis presents with high pH and high HCO₃ .
7. Respiratory alkalosis is characterized by:
A) High pH, low CO₂
B) Low pH, high CO₂
C) High pH, high HCO₃
D) Low pH, low HCO₃
Answer: A
Respiratory alkalosis: high pH, low CO₂ (hyperventilation) .
8. A patient with renal failure is likely to develop which acid-base imbalance?
A) Respiratory alkalosis
B) Metabolic acidosis
C) Metabolic alkalosis
D) Respiratory acidosis
, 3
Answer: B
Renal failure impairs excretion of hydrogen ions and reabsorption of bicarbonate, leading to
metabolic acidosis .
9. A patient with prolonged vomiting is at risk for:
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Answer: B
Vomiting causes loss of gastric acid (HCl), leading to metabolic alkalosis .
10. A patient with anxiety and hyperventilation is likely to develop:
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Answer: D
Hyperventilation causes excessive loss of CO₂, leading to respiratory alkalosis.
11. What is the primary compensation for metabolic acidosis?
A) Kidneys retain bicarbonate
B) Lungs increase ventilation to blow off CO₂
C) Lungs decrease ventilation to retain CO₂
D) Kidneys excrete bicarbonate
Answer: B
The lungs compensate for metabolic acidosis by increasing ventilation to blow off CO₂
(Kussmaul respirations).
12. What is the primary compensation for respiratory acidosis?
A) Lungs increase ventilation
B) Kidneys retain bicarbonate
C) Kidneys excrete bicarbonate
D) Lungs decrease ventilation
Answer: B
The kidneys compensate for respiratory acidosis by retaining bicarbonate (takes 24–48
hours).
13. A patient with salicylate (aspirin) poisoning is likely to develop:
