MCQ Quiz: Fluid

Fluid and electrolyte balance is a fundamental aspect of patient care, particularly in the critically ill. Pharmacists play a crucial role in the selection, dosing, and monitoring of intravenous fluids and electrolyte replacement therapies to ensure patient safety and optimize outcomes. This quiz for PharmD students will test your knowledge of basic physiology, types of IV fluids, management of common electrolyte disorders, and the clinical application of these principles in various practice settings.


1. The majority of the body’s total water is located in which compartment?

  • Intravascular
  • Interstitial
  • Intracellular
  • Transcellular

Answer: Intracellular


2. The primary cation in the extracellular fluid (ECF) is __________, while the primary cation in the intracellular fluid (ICF) is __________.

  • Potassium; Sodium
  • Sodium; Potassium
  • Calcium; Magnesium
  • Magnesium; Calcium

Answer: Sodium; Potassium


3. Which of the following IV fluids is considered an isotonic crystalloid?

  • 0.45% Sodium Chloride (1/2 NS)
  • Dextrose 5% in Water (D5W)
  • 0.9% Sodium Chloride (Normal Saline)
  • 3% Sodium Chloride

Answer: 0.9% Sodium Chloride (Normal Saline)


4. Dextrose 5% in Water (D5W) is considered isotonic in the bag, but after administration it becomes effectively _________ because the dextrose is rapidly metabolized.

  • Isotonic
  • Hypertonic
  • Hypotonic
  • A colloid

Answer: Hypotonic


5. A patient presents with severe dehydration and hypotension due to septic shock. Which type of IV fluid is most appropriate for initial, rapid volume resuscitation?

  • D5W
  • 0.45% NaCl
  • An isotonic crystalloid like 0.9% NaCl or Lactated Ringer’s.
  • 3% NaCl

Answer: An isotonic crystalloid like 0.9% NaCl or Lactated Ringer’s.


6. Lactated Ringer’s solution is often preferred over Normal Saline for large-volume resuscitation because it is a balanced solution that is less likely to cause:

  • Hyperkalemia
  • Hyponatremia
  • Hyperchloremic metabolic acidosis
  • Metabolic alkalosis

Answer: Hyperchloremic metabolic acidosis


7. Colloid solutions, like albumin, are different from crystalloids because they:

  • Freely distribute throughout the total body water.
  • Contain large molecules that primarily remain in the intravascular space, increasing oncotic pressure.
  • Are used for correcting free water deficits.
  • Are the first-line choice for maintenance fluids.

Answer: Contain large molecules that primarily remain in the intravascular space, increasing oncotic pressure.


8. A patient has a serum sodium level of 125 mEq/L and is experiencing symptoms of confusion and headache. This condition is known as:

  • Hypernatremia
  • Hyponatremia
  • Hyperkalemia
  • Hypokalemia

Answer: Hyponatremia


9. Rapid correction of chronic hyponatremia can lead to a severe neurological complication known as:

  • Cerebral edema
  • Osmotic demyelination syndrome.
  • A seizure.
  • A stroke.

Answer: Osmotic demyelination syndrome.


10. A patient with euvolemic, symptomatic hyponatremia might be treated with:

  • Aggressive IV fluid resuscitation with 0.9% NaCl.
  • A vasopressin receptor antagonist like tolvaptan.
  • Free water administration.
  • An insulin infusion.

Answer: A vasopressin receptor antagonist like tolvaptan.


11. A patient with a serum sodium of 158 mEq/L due to dehydration has hypernatremia. The primary goal of treatment is to correct the:

  • Total body sodium excess.
  • Free water deficit.
  • Total body potassium deficit.
  • Serum chloride level.

Answer: Free water deficit.


12. A patient has a serum potassium of 2.8 mEq/L. A common sign of this condition, hypokalemia, on an electrocardiogram (ECG) is:

  • Peaked T waves
  • A shortened QT interval
  • The presence of U waves
  • ST-segment elevation

Answer: The presence of U waves


13. A general rule of thumb for intravenous potassium repletion is that 10 mEq of KCl will raise the serum potassium by approximately:

  • 0.1 mEq/L
  • 0.5 mEq/L
  • 1.0 mEq/L
  • 1.5 mEq/L

Answer: 0.1 mEq/L


14. A patient with a serum potassium of 6.8 mEq/L and peaked T waves on their ECG has severe hyperkalemia. What is the most important first step to stabilize the cardiac membrane?

  • Administer intravenous calcium gluconate or calcium chloride.
  • Administer intravenous insulin and dextrose.
  • Administer sodium polystyrene sulfonate.
  • Administer a loop diuretic.

Answer: Administer intravenous calcium gluconate or calcium chloride.


15. Which of the following is a medication that can cause hyperkalemia?

  • Furosemide
  • Hydrochlorothiazide
  • Lisinopril
  • Amlodipine

Answer: Lisinopril


16. The “4/2/1 rule” is a common method for calculating:

  • A patient’s creatinine clearance.
  • The rate for maintenance IV fluids.
  • The dose of an antibiotic.
  • The risk of VTE.

Answer: The rate for maintenance IV fluids.


17. Using the 4/2/1 rule for a 70 kg patient, what would be the hourly maintenance fluid rate?

  • 70 mL/hr
  • 90 mL/hr
  • 110 mL/hr
  • 130 mL/hr

Answer: 110 mL/hr


18. A patient has a serum calcium of 7.5 mg/dL. This is known as hypocalcemia. It is important to also check which lab value, as it can affect the interpretation of the calcium level?

  • Sodium
  • Albumin
  • Glucose
  • Hemoglobin

Answer: Albumin


19. A positive Chvostek’s sign (facial muscle twitching) is a clinical sign of:

  • Hypercalcemia
  • Hypocalcemia
  • Hyperkalemia
  • Hypokalemia

Answer: Hypocalcemia


20. A patient has a serum magnesium of 1.1 mg/dL (hypomagnesemia). This electrolyte abnormality can make it difficult to correct which other electrolyte imbalance?

  • Sodium
  • Chloride
  • Potassium
  • Phosphate

Answer: Potassium


21. Torsades de pointes is a life-threatening cardiac arrhythmia that can be caused by severe hypomagnesemia. The treatment of choice is:

  • Intravenous calcium gluconate.
  • Intravenous magnesium sulfate.
  • Intravenous potassium chloride.
  • A bolus of normal saline.

Answer: Intravenous magnesium sulfate.


22. An arterial blood gas (ABG) shows: pH 7.25, PCO₂ 60 mmHg, HCO₃ 24 mEq/L. This is consistent with:

  • Metabolic acidosis
  • Metabolic alkalosis
  • Respiratory acidosis
  • Respiratory alkalosis

Answer: Respiratory acidosis


23. An ABG shows: pH 7.50, PCO₂ 30 mmHg, HCO₃ 23 mEq/L. This is consistent with:

  • Metabolic acidosis
  • Metabolic alkalosis
  • Respiratory acidosis
  • Respiratory alkalosis

Answer: Respiratory alkalosis


24. An ABG shows: pH 7.20, PCO₂ 40 mmHg, HCO₃ 15 mEq/L. This is consistent with:

  • Metabolic acidosis
  • Metabolic alkalosis
  • Respiratory acidosis
  • Respiratory alkalosis

Answer: Metabolic acidosis


25. A patient with diabetic ketoacidosis (DKA) is likely to have which type of acid-base disorder?

  • Anion gap metabolic acidosis
  • Non-anion gap metabolic acidosis
  • Respiratory acidosis
  • Metabolic alkalosis

Answer: Anion gap metabolic acidosis


26. The pharmacist’s role in fluid and electrolyte management includes:

  • Recommending the appropriate type and rate of IV fluids.
  • Calculating doses for electrolyte repletion.
  • Monitoring for signs of fluid overload or dehydration.
  • All of the above.

Answer: All of the above.


27. A patient in the ICU is receiving large volumes of IV fluids. Which of the following is a sign of fluid overload?

  • Tachycardia and hypotension.
  • Dry mucous membranes.
  • The development of pulmonary edema and peripheral edema.
  • A decrease in body weight.

Answer: The development of pulmonary edema and peripheral edema.


28. Why is it dangerous to administer intravenous potassium chloride as a rapid IV push?

  • It can cause a fatal cardiac arrhythmia.
  • It is very painful.
  • It is not effective when given rapidly.
  • It can cause severe hypertension.

Answer: It can cause a fatal cardiac arrhythmia.


29. A patient with severe heart failure is admitted to the hospital. Their fluid management strategy will likely involve:

  • Aggressive fluid administration.
  • Fluid restriction and the use of diuretics.
  • The use of colloid solutions only.
  • A high-sodium diet.

Answer: Fluid restriction and the use of diuretics.


30. The term “osmolarity” refers to the concentration of:

  • Solute particles per kilogram of solvent.
  • Solute particles per liter of solution.
  • Only sodium and chloride ions in a solution.
  • Only large molecules like albumin.

Answer: Solute particles per liter of solution.


31. Administration of a hypertonic solution like 3% NaCl would cause water to move:

  • From the intravascular space into the cells.
  • From the cells into the intravascular space.
  • There would be no net movement of water.
  • From the interstitial space into the cells.

Answer: From the cells into the intravascular space.


32. A patient with a traumatic brain injury and increased intracranial pressure may be treated with which type of fluid to reduce cerebral edema?

  • 0.45% NaCl
  • D5W
  • Lactated Ringer’s
  • Hypertonic saline (e.g., 3% NaCl)

Answer: Hypertonic saline (e.g., 3% NaCl)


33. The primary reason for using a “balanced” crystalloid like Lactated Ringer’s is that its composition more closely resembles:

  • Intracellular fluid.
  • The blood plasma.
  • Pure water.
  • Gastric fluid.

Answer: The blood plasma.


34. A patient is receiving Total Parenteral Nutrition (TPN). The pharmacist is responsible for ensuring the TPN formulation:

  • Is calorically dense enough to meet the patient’s needs.
  • Contains the correct amount of electrolytes.
  • Is stable and compatible.
  • All of the above.

Answer: All of the above.


35. A patient with a high nasogastric tube output is losing stomach acid. They are at risk for developing which acid-base disorder?

  • Metabolic acidosis
  • Metabolic alkalosis
  • Respiratory acidosis
  • Respiratory alkalosis

Answer: Metabolic alkalosis


36. The body’s primary buffer system to maintain a stable pH is the:

  • Phosphate buffer system.
  • Protein buffer system.
  • Hemoglobin buffer system.
  • Carbonic acid-bicarbonate buffer system.

Answer: Carbonic acid-bicarbonate buffer system.


37. Insulin and dextrose are used to treat hyperkalemia because they:

  • Increase the renal excretion of potassium.
  • Cause an intracellular shift of potassium from the blood into the cells.
  • Bind potassium in the gut.
  • Stabilize the cardiac membrane.

Answer: Cause an intracellular shift of potassium from the blood into the cells.


38. A pharmacist’s knowledge of _________ is essential for adjusting drug doses in a patient with acute kidney injury and fluid imbalance.

  • Pharmacokinetics
  • Medicinal chemistry
  • Pharmacy law
  • Marketing

Answer: Pharmacokinetics


39. A patient receiving large volumes of 0.9% NaCl is at risk for developing hyperchloremia and:

  • Hypernatremia.
  • Hyponatremia.
  • Hyperkalemia.
  • Hypokalemia.

Answer: Hypernatremia.


40. The main difference between crystalloids and colloids is that crystalloids contain:

  • Large molecules that do not easily cross capillary membranes.
  • Water and small-molecule solutes like electrolytes and dextrose that can pass freely out of the intravascular space.
  • Only pure water.
  • Red blood cells.

Answer: Water and small-molecule solutes like electrolytes and dextrose that can pass freely out of the intravascular space.


41. A patient with symptomatic hypercalcemia may be treated with:

  • IV calcium gluconate.
  • IV fluids and a bisphosphonate.
  • Oral calcium supplements.
  • Vitamin D.

Answer: IV fluids and a bisphosphonate.


42. The pharmacist in the ICU is a critical member of the interprofessional team for managing fluids and electrolytes because of their expertise in:

  • Pharmacology and pharmacokinetics.
  • Sterile compounding of IV admixtures.
  • Drug information.
  • All of the above.

Answer: All of the above.


43. A patient with severe diarrhea is losing large amounts of bicarbonate. They are at risk for developing which acid-base disorder?

  • Non-anion gap metabolic acidosis
  • Anion gap metabolic acidosis
  • Metabolic alkalosis
  • Respiratory alkalosis

Answer: Non-anion gap metabolic acidosis


44. A patient’s fluid status can be assessed by monitoring:

  • Daily weights.
  • Urine output.
  • Blood pressure and heart rate.
  • All of the above.

Answer: All of the above.


45. Which of the following is a potassium-sparing diuretic?

  • Furosemide
  • Hydrochlorothiazide
  • Spironolactone
  • Bumetanide

Answer: Spironolactone


46. The use of a “smart pump” with a drug library for IV electrolyte infusions is a safety measure to prevent:

  • Dosing and infusion rate errors.
  • Drug shortages.
  • Incompatibilities.
  • The need for pharmacist verification.

Answer: Dosing and infusion rate errors.


47. A pharmacist should recommend that a patient taking a loop diuretic like furosemide also be monitored for:

  • Hyperkalemia
  • Hypokalemia
  • Hypernatremia
  • Hypercalcemia

Answer: Hypokalemia


48. Why is it important to consider the sodium content of IV antibiotic admixtures in a fluid-restricted patient?

  • The extra sodium can contribute significantly to the patient’s daily fluid and sodium load.
  • It is not an important consideration.
  • All IV antibiotics are sodium-free.
  • It only matters if the patient has a high fever.

Answer: The extra sodium can contribute significantly to the patient’s daily fluid and sodium load.


49. A key leadership role for a critical care pharmacist is to:

  • Develop and implement evidence-based protocols for fluid and electrolyte management.
  • Make all patient care decisions independently.
  • Manage the ICU nursing schedule.
  • Order all lab tests.

Answer: Develop and implement evidence-based protocols for fluid and electrolyte management.


50. The ultimate goal of fluid and electrolyte therapy is to:

  • Normalize all lab values, regardless of the patient’s clinical status.
  • Restore and maintain physiologic homeostasis and ensure adequate organ perfusion.
  • Use the most expensive IV fluid products available.
  • Administer as much IV fluid as possible.

Answer: Restore and maintain physiologic homeostasis and ensure adequate organ perfusion.

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