NSG 4100 Exam 3: Complex Perfusion & Oxygenation Problems
150+ Questions with Correct Answers and Rationales 100%
PASS!
SECTION 1: ACID-BASE & ELECTROLYTE IMBALANCES (Questions
1-15)
Question 1
A patient with diabetic ketoacidosis (DKA) is exhibiting Kussmaul respirations. The nurse
understands that this respiratory pattern is a compensatory mechanism for which acid-base
imbalance?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: A
Rationale: Kussmaul respirations (deep, rapid breathing) are a compensatory mechanism for metabolic
acidosis. In DKA, the body attempts to blow off CO2 to increase pH and compensate for the acidosis.
Metabolic alkalosis (B) would cause hypoventilation. Respiratory acidosis (C) would cause
hypoventilation to retain CO2. Respiratory alkalosis (D) would be caused by hyperventilation.
Question 2
A patient with chronic obstructive pulmonary disease (COPD) has the following ABG results: pH
7.32, PaCO2 55, HCO3 30. The nurse interprets these results as:
A) Uncompensated respiratory acidosis
B) Partially compensated respiratory acidosis
C) Fully compensated respiratory acidosis
D) Metabolic acidosis with respiratory compensation
Correct Answer: C
,Rationale: In fully compensated respiratory acidosis, the pH is within normal range (7.35-7.45), PaCO2 is
elevated (>45), and HCO3 is elevated (>26). The kidneys have compensated for the respiratory acidosis
by retaining bicarbonate. In uncompensated (A), pH is abnormal. In partially compensated (B), pH is
abnormal but some compensation has occurred. Metabolic acidosis with respiratory compensation (D)
would show low pH, low HCO3, and low PaCO2.
Question 3
Which ABG result indicates metabolic alkalosis?
A) pH 7.30, PaCO2 50, HCO3 24
B) pH 7.48, PaCO2 48, HCO3 32
C) pH 7.48, PaCO2 32, HCO3 24
D) pH 7.30, PaCO2 32, HCO3 18
Correct Answer: B
Rationale: Metabolic alkalosis is characterized by elevated pH (>7.45) and elevated HCO3 (>26). The
PaCO2 may be elevated if respiratory compensation is occurring. Option A shows respiratory acidosis.
Option C shows respiratory alkalosis. Option D shows metabolic acidosis with respiratory compensation.
Question 4
A patient with renal failure has the following ABG results: pH 7.25, PaCO2 30, HCO3 14. The nurse
should interpret these results as:
A) Uncompensated metabolic acidosis
B) Partially compensated metabolic acidosis
C) Fully compensated metabolic acidosis
D) Respiratory acidosis with metabolic compensation
Correct Answer: B
Rationale: Metabolic acidosis is indicated by low pH (<7.35) and low HCO3 (<22). The PaCO2 is low
(30), indicating the respiratory system is attempting to compensate by blowing off CO2. Since the pH is
still abnormal, this is partially compensated metabolic acidosis. In fully compensated (C), the pH would be
normal. In uncompensated (A), the PaCO2 would be normal. Respiratory acidosis with metabolic
compensation (D) would show elevated PaCO2.
Question 5
,A patient with salicylate toxicity is hyperventilating. Which acid-base imbalance is most likely?
A) Metabolic acidosis
B) Respiratory acidosis
C) Respiratory alkalosis initially, then metabolic acidosis
D) Metabolic alkalosis
Correct Answer: C
Rationale: Salicylate toxicity initially stimulates the respiratory center, causing hyperventilation and
respiratory alkalosis. As toxicity progresses, it causes metabolic acidosis by uncoupling oxidative
phosphorylation. The combination results in a mixed acid-base disorder. Salicylates do not directly cause
metabolic alkalosis (D).
Question 6
The nurse is caring for a patient with a nasogastric tube to suction. Which acid-base imbalance is
the patient at risk for developing?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: B
Rationale: Nasogastric suction removes gastric acid (HCl), leading to a loss of hydrogen ions and
metabolic alkalosis. The kidneys attempt to compensate by retaining hydrogen ions and excreting
bicarbonate. Metabolic acidosis (A) would occur with loss of bicarbonate (e.g., diarrhea). Respiratory
imbalances (C, D) would be caused by ventilation issues.
Question 7
A patient with severe diarrhea is at risk for which acid-base imbalance?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: A
Rationale: Severe diarrhea causes loss of bicarbonate from the gastrointestinal tract, leading to
metabolic acidosis. The loss of bicarbonate reduces the body's buffering capacity, resulting in acidemia.
Metabolic alkalosis (B) occurs with loss of gastric acid (e.g., vomiting, NG suction).
, Question 8
The nurse is reviewing ABG results for a patient with chronic respiratory failure. Which finding is
expected?
A) pH 7.32, PaCO2 58, HCO3 32
B) pH 7.48, PaCO2 32, HCO3 24
C) pH 7.38, PaCO2 30, HCO3 18
D) pH 7.30, PaCO2 35, HCO3 18
**Correct Answer: A
Rationale: In chronic respiratory failure, the body compensates for elevated PaCO2 by retaining
bicarbonate. This results in an elevated HCO3 (>26) and a pH that may be near normal or slightly low.
Option A shows compensated respiratory acidosis. Option B shows respiratory alkalosis. Option C shows
metabolic acidosis with respiratory compensation. Option D shows uncompensated metabolic acidosis.
Question 9
A patient is receiving mechanical ventilation with hyperventilation settings. Which acid-base
imbalance should the nurse monitor for?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: D
Rationale: Hyperventilation causes excessive loss of CO2, leading to respiratory alkalosis. This can
occur with mechanical ventilation settings that deliver too many breaths per minute or too large tidal
volumes. Metabolic acidosis (A) would be caused by loss of bicarbonate or accumulation of acids.
Question 10
A patient has the following ABG results: pH 7.48, PaCO2 48, HCO3 32. The nurse interprets this
as:
A) Uncompensated metabolic alkalosis
B) Partially compensated metabolic alkalosis
150+ Questions with Correct Answers and Rationales 100%
PASS!
SECTION 1: ACID-BASE & ELECTROLYTE IMBALANCES (Questions
1-15)
Question 1
A patient with diabetic ketoacidosis (DKA) is exhibiting Kussmaul respirations. The nurse
understands that this respiratory pattern is a compensatory mechanism for which acid-base
imbalance?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: A
Rationale: Kussmaul respirations (deep, rapid breathing) are a compensatory mechanism for metabolic
acidosis. In DKA, the body attempts to blow off CO2 to increase pH and compensate for the acidosis.
Metabolic alkalosis (B) would cause hypoventilation. Respiratory acidosis (C) would cause
hypoventilation to retain CO2. Respiratory alkalosis (D) would be caused by hyperventilation.
Question 2
A patient with chronic obstructive pulmonary disease (COPD) has the following ABG results: pH
7.32, PaCO2 55, HCO3 30. The nurse interprets these results as:
A) Uncompensated respiratory acidosis
B) Partially compensated respiratory acidosis
C) Fully compensated respiratory acidosis
D) Metabolic acidosis with respiratory compensation
Correct Answer: C
,Rationale: In fully compensated respiratory acidosis, the pH is within normal range (7.35-7.45), PaCO2 is
elevated (>45), and HCO3 is elevated (>26). The kidneys have compensated for the respiratory acidosis
by retaining bicarbonate. In uncompensated (A), pH is abnormal. In partially compensated (B), pH is
abnormal but some compensation has occurred. Metabolic acidosis with respiratory compensation (D)
would show low pH, low HCO3, and low PaCO2.
Question 3
Which ABG result indicates metabolic alkalosis?
A) pH 7.30, PaCO2 50, HCO3 24
B) pH 7.48, PaCO2 48, HCO3 32
C) pH 7.48, PaCO2 32, HCO3 24
D) pH 7.30, PaCO2 32, HCO3 18
Correct Answer: B
Rationale: Metabolic alkalosis is characterized by elevated pH (>7.45) and elevated HCO3 (>26). The
PaCO2 may be elevated if respiratory compensation is occurring. Option A shows respiratory acidosis.
Option C shows respiratory alkalosis. Option D shows metabolic acidosis with respiratory compensation.
Question 4
A patient with renal failure has the following ABG results: pH 7.25, PaCO2 30, HCO3 14. The nurse
should interpret these results as:
A) Uncompensated metabolic acidosis
B) Partially compensated metabolic acidosis
C) Fully compensated metabolic acidosis
D) Respiratory acidosis with metabolic compensation
Correct Answer: B
Rationale: Metabolic acidosis is indicated by low pH (<7.35) and low HCO3 (<22). The PaCO2 is low
(30), indicating the respiratory system is attempting to compensate by blowing off CO2. Since the pH is
still abnormal, this is partially compensated metabolic acidosis. In fully compensated (C), the pH would be
normal. In uncompensated (A), the PaCO2 would be normal. Respiratory acidosis with metabolic
compensation (D) would show elevated PaCO2.
Question 5
,A patient with salicylate toxicity is hyperventilating. Which acid-base imbalance is most likely?
A) Metabolic acidosis
B) Respiratory acidosis
C) Respiratory alkalosis initially, then metabolic acidosis
D) Metabolic alkalosis
Correct Answer: C
Rationale: Salicylate toxicity initially stimulates the respiratory center, causing hyperventilation and
respiratory alkalosis. As toxicity progresses, it causes metabolic acidosis by uncoupling oxidative
phosphorylation. The combination results in a mixed acid-base disorder. Salicylates do not directly cause
metabolic alkalosis (D).
Question 6
The nurse is caring for a patient with a nasogastric tube to suction. Which acid-base imbalance is
the patient at risk for developing?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: B
Rationale: Nasogastric suction removes gastric acid (HCl), leading to a loss of hydrogen ions and
metabolic alkalosis. The kidneys attempt to compensate by retaining hydrogen ions and excreting
bicarbonate. Metabolic acidosis (A) would occur with loss of bicarbonate (e.g., diarrhea). Respiratory
imbalances (C, D) would be caused by ventilation issues.
Question 7
A patient with severe diarrhea is at risk for which acid-base imbalance?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: A
Rationale: Severe diarrhea causes loss of bicarbonate from the gastrointestinal tract, leading to
metabolic acidosis. The loss of bicarbonate reduces the body's buffering capacity, resulting in acidemia.
Metabolic alkalosis (B) occurs with loss of gastric acid (e.g., vomiting, NG suction).
, Question 8
The nurse is reviewing ABG results for a patient with chronic respiratory failure. Which finding is
expected?
A) pH 7.32, PaCO2 58, HCO3 32
B) pH 7.48, PaCO2 32, HCO3 24
C) pH 7.38, PaCO2 30, HCO3 18
D) pH 7.30, PaCO2 35, HCO3 18
**Correct Answer: A
Rationale: In chronic respiratory failure, the body compensates for elevated PaCO2 by retaining
bicarbonate. This results in an elevated HCO3 (>26) and a pH that may be near normal or slightly low.
Option A shows compensated respiratory acidosis. Option B shows respiratory alkalosis. Option C shows
metabolic acidosis with respiratory compensation. Option D shows uncompensated metabolic acidosis.
Question 9
A patient is receiving mechanical ventilation with hyperventilation settings. Which acid-base
imbalance should the nurse monitor for?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: D
Rationale: Hyperventilation causes excessive loss of CO2, leading to respiratory alkalosis. This can
occur with mechanical ventilation settings that deliver too many breaths per minute or too large tidal
volumes. Metabolic acidosis (A) would be caused by loss of bicarbonate or accumulation of acids.
Question 10
A patient has the following ABG results: pH 7.48, PaCO2 48, HCO3 32. The nurse interprets this
as:
A) Uncompensated metabolic alkalosis
B) Partially compensated metabolic alkalosis
