Guide: Verified MCQ & ABG Rationale
(2026-2027 Edition)
Part 1: Fluid & Electrolyte Imbalances
1. A patient with heart failure is admitted with a potassium level of 6.5 mEq/L.
Which medication should the nurse anticipate administering to move
potassium into the intracellular space?
A) Furosemide
B) Regular Insulin and Dextrose 50%
C) Spironolactone
D) Magnesium Sulfate
Answer: B
Rationale: Insulin shifts potassium into cells by stimulating the Na⁺-K⁺ ATPase
pump. Dextrose is given simultaneously to prevent hypoglycemia. Furosemide and
spironolactone affect potassium excretion, not intracellular shifting .
2. A nurse is caring for a patient with a sodium level of 120 mEq/L. The
provider orders an infusion of 3% Sodium Chloride. What is the priority
nursing assessment?
A) Peripheral edema
B) Lung sounds (crackles) and neurological status
C) Hourly urine output
D) Skin turgor
Answer: B
Rationale: 3% NS is hypertonic and pulls fluid into the vascular space, risking
pulmonary edema and fluid overload. Neurological status must be monitored as
rapid sodium correction can cause central pontine myelinolysis .
,3. While assessing a patient with hypocalcemia, the nurse inflates a blood
pressure cuff on the patient's arm. The patient's hand develops a carpal
spasm. How should this be documented?
A) Positive Chvostek's sign
B) Positive Trousseau's sign
C) Positive Babinski sign
D) Negative Allen test
Answer: B
Rationale: Trousseau's sign is a carpal spasm induced by ischemia from a blood
pressure cuff, indicating neuromuscular irritability from low calcium .
4. A patient has a magnesium level of 1.1 mEq/L. Which assessment finding is
most consistent with this lab value?
A) Diminished deep tendon reflexes (DTRs)
B) Hyperactive deep tendon reflexes (DTRs) and tremors
C) Lethargy and bradycardia
D) Hypotension
Answer: B
Rationale: Low magnesium "speeds up" the nervous system by lowering the
seizure threshold, leading to hyperreflexia, tremors, and potential seizures .
5. A patient taking Furosemide (Lasix) reports muscle weakness and leg
cramps. The nurse suspects which electrolyte imbalance?
A) Hyperkalemia
B) Hypokalemia
C) Hypercalcemia
D) Hyponatremia
Answer: B
,Rationale: Loop diuretics are potassium-wasting; low potassium causes muscle
weakness, cramps, and fatigue .
6. A patient is admitted with hypernatremia (Sodium 158 mEq/L). Which IV
fluid is most appropriate?
A) 0.9% Normal Saline
B) 0.45% Normal Saline
C) 3% Normal Saline
D) Lactated Ringer's
Answer: B
Rationale: Hypernatremia requires a hypotonic solution to dilute the sodium and
rehydrate cells .
7. A patient with renal failure has a magnesium level of 3.8 mEq/L. Which
finding would cause the most concern?
A) Hyperactive bowel sounds
B) Absent deep tendon reflexes and respiratory depression
C) Tachycardia
D) Increased thirst
Answer: B
Rationale: High magnesium acts as a CNS depressant, suppressing reflexes and
potentially causing respiratory arrest .
8. A patient has been undergoing prolonged nasogastric (NG) suctioning.
Which electrolyte imbalance should the nurse prioritize?
A) Hyperkalemia
B) Hypokalemia
C) Hypermagnesemia
D) Hypernatremia
, Answer: B
Rationale: Gastric fluids are rich in potassium; suctioning removes it, leading to
hypokalemia .
9. A patient with hypocalcemia exhibits facial twitching when the nurse taps
the facial nerve. This is documented as:
A) Positive Trousseau's sign
B) Positive Chvostek's sign
C) Positive Babinski reflex
D) Positive Kernig's sign
Answer: B
Rationale: Chvostek's sign is twitching of facial muscles when the facial nerve is
tapped, indicating hypocalcemia .
10. Which IV fluid should the nurse question if ordered for a patient with
heart failure?
A) 0.9% Normal Saline
B) 0.45% Normal Saline
C) Lactated Ringer's
D) 5% Dextrose in Water
Answer: A
Rationale: 0.9% NS is isotonic and can worsen fluid volume overload in heart
failure patients .
11. A patient's lab results show calcium 8.0 mg/dL and albumin 3.0 g/dL. The
nurse calculates the corrected calcium. What is the approximate corrected
calcium?
A) 8.0 mg/dL
B) 8.4 mg/dL