MDC III FINAL EXAM AND STUDY GUIDE
NEWEST 2026 TEST BANK | COMPLETE 200 REAL EXAM
QUESTIONS
MDC 3 FINAL EXAM PREP (RASMUSSEN)
SECTION 1: FLUID, ELECTROLYTE, & ACID-BASE
BALANCE
Question 1
A patient with heart failure has a serum potassium level of 2.8 mEq/L. Which ECG
change should the nurse expect to observe?
A) Peaked T waves
B) U waves
C) Wide QRS complex
D) Absent P waves
Correct Answer: B
Rationale: Hypokalemia (potassium <3.5 mEq/L) is characterized by U waves, flat T
waves, and ST depression on ECG. Peaked T waves are characteristic of hyperkalemia.
Wide QRS complexes and absent P waves are also associated with hyperkalemia. The
nurse should monitor the patient for cardiac dysrhythmias and report potassium levels
below 3.5 promptly. Treatment includes oral or IV potassium replacement, and the nurse
should monitor for signs of hyperkalemia as replacement is administered.
,Question 2
A patient presents with muscle twitching, tetany, and a positive Chvostek's sign. Which
electrolyte imbalance is most likely?
A) Hypernatremia
B) Hypocalcemia
C) Hyperkalemia
D) Hypermagnesemia
Correct Answer: B
Rationale: Hypocalcemia (calcium <8.5 mg/dL) causes neuromuscular irritability,
including muscle twitching, tetany, Chvostek's sign (facial twitching when tapping the
facial nerve), and Trousseau's sign (carpal spasm with blood pressure cuff inflation).
Hypercalcemia causes lethargy, weakness, and shortened QT intervals. The nurse should
assess for these signs in patients at risk for hypocalcemia, such as those with pancreatitis
or chronic kidney disease.
Question 3
A nurse is caring for a patient with severe vomiting. Arterial blood gas results show pH
7.50, PaCO2 48, HCO3 32. Which condition does this represent?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: B
Rationale: Vomiting causes loss of gastric acid (HCl), leading to metabolic alkalosis. This
is characterized by pH >7.45 and elevated HCO3 (>26 mEq/L). The respiratory system
attempts to compensate by hypoventilating (retaining CO2), as reflected by the elevated
PaCO2. Metabolic acidosis presents with low pH and low HCO3. The nurse should
monitor the patient's electrolyte status, particularly potassium, which may be depleted
with prolonged vomiting.
,Question 4
A patient with acute kidney injury (AKI) has a potassium level of 6.8 mEq/L. Which
intervention should the nurse implement first?
A) Administer sodium polystyrene sulfonate (Kayexalate)
B) Prepare for hemodialysis
C) Administer IV calcium gluconate
D) Administer IV insulin with dextrose
Correct Answer: C
Rationale: In severe hyperkalemia (>6.5 mEq/L) with ECG changes, the first priority is
cardiac stabilization with IV calcium gluconate to protect the myocardium from the
effects of hyperkalemia. Insulin with dextrose shifts potassium into cells as a temporizing
measure. Kayexalate binds potassium in the GI tract for excretion. Hemodialysis is the
definitive treatment for severe hyperkalemia in AKI. The priority is to prevent life-
threatening cardiac arrhythmias.
Question 5
A patient with diabetic ketoacidosis (DKA) has a potassium level of 5.5 mEq/L on
admission. After starting insulin, the nurse should anticipate:
A) Potassium will rise further
B) Potassium will decrease (shift into cells)
C) No change in potassium
D) Potassium will convert to sodium
Correct Answer: B
Rationale: Insulin drives potassium into cells, which can lead to hypokalemia as
treatment progresses. Although initial potassium may be normal or elevated due to
acidosis shifting potassium out of cells, potassium levels will drop with insulin therapy.
The nurse should monitor potassium closely and be prepared to replace it. This is a
critical safety consideration in DKA management.
Question 6
Which ECG change is characteristic of hypercalcemia?
, A) Shortened QT interval
B) Prolonged QT interval
C) Peaked T waves
D) U waves
Correct Answer: A
Rationale: Hypercalcemia shortens the QT interval. Hypocalcemia prolongs the QT
interval. U waves are associated with hypokalemia. Peaked T waves indicate
hyperkalemia. The nurse should monitor ECG changes in patients with electrolyte
imbalances and report significant findings to the provider.
Question 7
A patient with pancreatitis has a calcium level of 6.8 mg/dL. The nurse should assess for:
A) Trousseau's sign
B) Positive Babinski
C) Hyperreflexia
D) Muscle flaccidity
Correct Answer: A
Rationale: Hypocalcemia (normal 8.5–10.2 mg/dL) causes tetany, Trousseau's sign, and
Chvostek's sign. Pancreatitis causes fat saponification, which binds calcium and leads to
hypocalcemia. Trousseau's sign is elicited by inflating a blood pressure cuff on the upper
arm, which causes carpal spasm in hypocalcemic patients. The nurse should assess for
signs of hypocalcemia in patients with pancreatitis.
Question 8
A patient's ABG shows: pH 7.48, PaCO2 30, HCO3 22. This represents:
A) Metabolic alkalosis
B) Respiratory alkalosis
C) Metabolic acidosis
D) Respiratory acidosis
Correct Answer: B
NEWEST 2026 TEST BANK | COMPLETE 200 REAL EXAM
QUESTIONS
MDC 3 FINAL EXAM PREP (RASMUSSEN)
SECTION 1: FLUID, ELECTROLYTE, & ACID-BASE
BALANCE
Question 1
A patient with heart failure has a serum potassium level of 2.8 mEq/L. Which ECG
change should the nurse expect to observe?
A) Peaked T waves
B) U waves
C) Wide QRS complex
D) Absent P waves
Correct Answer: B
Rationale: Hypokalemia (potassium <3.5 mEq/L) is characterized by U waves, flat T
waves, and ST depression on ECG. Peaked T waves are characteristic of hyperkalemia.
Wide QRS complexes and absent P waves are also associated with hyperkalemia. The
nurse should monitor the patient for cardiac dysrhythmias and report potassium levels
below 3.5 promptly. Treatment includes oral or IV potassium replacement, and the nurse
should monitor for signs of hyperkalemia as replacement is administered.
,Question 2
A patient presents with muscle twitching, tetany, and a positive Chvostek's sign. Which
electrolyte imbalance is most likely?
A) Hypernatremia
B) Hypocalcemia
C) Hyperkalemia
D) Hypermagnesemia
Correct Answer: B
Rationale: Hypocalcemia (calcium <8.5 mg/dL) causes neuromuscular irritability,
including muscle twitching, tetany, Chvostek's sign (facial twitching when tapping the
facial nerve), and Trousseau's sign (carpal spasm with blood pressure cuff inflation).
Hypercalcemia causes lethargy, weakness, and shortened QT intervals. The nurse should
assess for these signs in patients at risk for hypocalcemia, such as those with pancreatitis
or chronic kidney disease.
Question 3
A nurse is caring for a patient with severe vomiting. Arterial blood gas results show pH
7.50, PaCO2 48, HCO3 32. Which condition does this represent?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: B
Rationale: Vomiting causes loss of gastric acid (HCl), leading to metabolic alkalosis. This
is characterized by pH >7.45 and elevated HCO3 (>26 mEq/L). The respiratory system
attempts to compensate by hypoventilating (retaining CO2), as reflected by the elevated
PaCO2. Metabolic acidosis presents with low pH and low HCO3. The nurse should
monitor the patient's electrolyte status, particularly potassium, which may be depleted
with prolonged vomiting.
,Question 4
A patient with acute kidney injury (AKI) has a potassium level of 6.8 mEq/L. Which
intervention should the nurse implement first?
A) Administer sodium polystyrene sulfonate (Kayexalate)
B) Prepare for hemodialysis
C) Administer IV calcium gluconate
D) Administer IV insulin with dextrose
Correct Answer: C
Rationale: In severe hyperkalemia (>6.5 mEq/L) with ECG changes, the first priority is
cardiac stabilization with IV calcium gluconate to protect the myocardium from the
effects of hyperkalemia. Insulin with dextrose shifts potassium into cells as a temporizing
measure. Kayexalate binds potassium in the GI tract for excretion. Hemodialysis is the
definitive treatment for severe hyperkalemia in AKI. The priority is to prevent life-
threatening cardiac arrhythmias.
Question 5
A patient with diabetic ketoacidosis (DKA) has a potassium level of 5.5 mEq/L on
admission. After starting insulin, the nurse should anticipate:
A) Potassium will rise further
B) Potassium will decrease (shift into cells)
C) No change in potassium
D) Potassium will convert to sodium
Correct Answer: B
Rationale: Insulin drives potassium into cells, which can lead to hypokalemia as
treatment progresses. Although initial potassium may be normal or elevated due to
acidosis shifting potassium out of cells, potassium levels will drop with insulin therapy.
The nurse should monitor potassium closely and be prepared to replace it. This is a
critical safety consideration in DKA management.
Question 6
Which ECG change is characteristic of hypercalcemia?
, A) Shortened QT interval
B) Prolonged QT interval
C) Peaked T waves
D) U waves
Correct Answer: A
Rationale: Hypercalcemia shortens the QT interval. Hypocalcemia prolongs the QT
interval. U waves are associated with hypokalemia. Peaked T waves indicate
hyperkalemia. The nurse should monitor ECG changes in patients with electrolyte
imbalances and report significant findings to the provider.
Question 7
A patient with pancreatitis has a calcium level of 6.8 mg/dL. The nurse should assess for:
A) Trousseau's sign
B) Positive Babinski
C) Hyperreflexia
D) Muscle flaccidity
Correct Answer: A
Rationale: Hypocalcemia (normal 8.5–10.2 mg/dL) causes tetany, Trousseau's sign, and
Chvostek's sign. Pancreatitis causes fat saponification, which binds calcium and leads to
hypocalcemia. Trousseau's sign is elicited by inflating a blood pressure cuff on the upper
arm, which causes carpal spasm in hypocalcemic patients. The nurse should assess for
signs of hypocalcemia in patients with pancreatitis.
Question 8
A patient's ABG shows: pH 7.48, PaCO2 30, HCO3 22. This represents:
A) Metabolic alkalosis
B) Respiratory alkalosis
C) Metabolic acidosis
D) Respiratory acidosis
Correct Answer: B
