MCQ on Fluid and Electrolyte Imbalance

Fluid & Electrolyte Mastery Quiz

Test your knowledge of nursing fundamentals

Score: 0/100

Question 1/100

Category 1: Fluid Compartments & Homeostasis

1. What percentage of the adult body is composed of water?

30% 40% 60% 80%

Answer: 60%

Explanation: In a healthy adult, about 60% of total body weight is water.

2. The majority of body fluid is located in which compartment?

Intravascular Interstitial Intracellular Transcellular

Answer: Intracellular

Explanation: Approximately two-thirds of body water is located inside the cells, in the intracellular space.

3. Which hormone regulates water reabsorption in the kidneys?

Aldosterone ADH (Antidiuretic hormone) Renin ANP

Answer: ADH (Antidiuretic hormone)

Explanation: ADH acts on the kidneys to promote water reabsorption and maintain fluid balance.

4. Which pressure pulls fluid into capillaries from interstitial space?

Hydrostatic pressure Osmotic pressure Oncotic pressure Filtration pressure

Answer: Oncotic pressure

Explanation: Oncotic pressure, caused by plasma proteins, pulls water into the circulatory system.

5. Which electrolyte has the highest concentration in the intracellular fluid?

Sodium Potassium Calcium Chloride

Answer: Potassium

Explanation: Potassium is the major cation in intracellular fluid and essential for cell function.

6. What mechanism is responsible for movement of water between compartments?

Active transport Diffusion Filtration Osmosis

Answer: Osmosis

Explanation: Osmosis moves water from areas of low solute concentration to high solute concentration across membranes.

7. Aldosterone primarily affects which electrolyte balance?

Calcium Potassium Sodium Phosphate

Answer: Sodium

Explanation: Aldosterone increases sodium reabsorption and potassium excretion in the renal tubules.

8. The thirst mechanism is primarily controlled by:

Pituitary gland Adrenal cortex Hypothalamus Medulla

Answer: Hypothalamus

Explanation: The hypothalamus detects increased osmolality and triggers thirst to restore fluid balance.

9. Which of the following is a transcellular fluid?

Synovial fluid Interstitial fluid Plasma Lymph

Answer: Synovial fluid

Explanation: Transcellular fluids include synovial, cerebrospinal, and pleural fluids, separate from interstitial or plasma compartments.

10. Which fluid compartment is plasma a part of?

Intracellular Interstitial Intravascular Transcellular

Answer: Intravascular

Explanation: Plasma is the fluid portion of blood found within the intravascular space.

Category 2: Edema and Fluid Movement

11. What is edema?

Dehydration of tissues Excess fluid in the intracellular space Excess fluid in the interstitial space Fluid accumulation in blood vessels

Answer: Excess fluid in the interstitial space

Explanation: Edema is caused by accumulation of fluid in the interstitial tissue spaces.

12. Which of the following contributes to edema formation?

Increased plasma oncotic pressure Increased capillary hydrostatic pressure Decreased capillary permeability Lymphatic drainage increase

Answer: Increased capillary hydrostatic pressure

Explanation: Edema occurs when hydrostatic pressure pushes fluid out of capillaries into the interstitial space.

13. Which condition commonly causes edema due to low oncotic pressure?

Liver failure Hypertension Diabetes insipidus Hyperkalemia

Answer: Liver failure

Explanation: Liver failure reduces albumin production, lowering plasma oncotic pressure and causing edema.

14. What type of edema is seen in heart failure?

Pitting edema Non-pitting edema Cerebral edema Pulmonary edema

Answer: Pitting edema

Explanation: Right-sided heart failure leads to increased venous pressure and pitting edema in dependent areas.

15. What is a key characteristic of non-pitting edema?

Leaves a depression when pressed Common in protein-deficient states Often associated with lymphatic obstruction Caused by increased sodium

Answer: Often associated with lymphatic obstruction

Explanation: Non-pitting edema occurs when lymphatic drainage is impaired and does not indent when pressed.

16. Which electrolyte is most involved in fluid shift and edema?

Calcium Potassium Sodium Magnesium

Answer: Sodium

Explanation: Sodium attracts water, and its retention causes fluid accumulation in extracellular compartments.

17. Which of the following reduces edema?

Decreased plasma proteins Increased capillary permeability Diuretics Vasodilation

Answer: Diuretics

Explanation: Diuretics increase fluid excretion, helping to reduce fluid accumulation in the tissues.

18. Which type of fluid shift occurs in burns?

Intravascular to interstitial Interstitial to intracellular Interstitial to intravascular Intracellular to intravascular

Answer: Intravascular to interstitial

Explanation: Burn injuries increase capillary permeability, causing fluid to leak into interstitial spaces.

19. Which plasma protein helps maintain oncotic pressure?

Hemoglobin Fibrinogen Albumin Globulin

Answer: Albumin

Explanation: Albumin is the most abundant plasma protein that pulls fluid into the bloodstream via oncotic pressure.

20. A decrease in which factor will worsen edema?

Hydrostatic pressure Capillary permeability Plasma protein level Interstitial fluid volume

Answer: Plasma protein level

Explanation: Low plasma proteins like albumin reduce oncotic pressure, promoting fluid shift into interstitial spaces.

Category 3: Fluid Volume Deficit and Excess

21. Which of the following is a sign of fluid volume deficit?

Edema Jugular vein distension Tachycardia Weight gain

Answer: Tachycardia

Explanation: Tachycardia is a compensatory response to hypovolemia to maintain blood pressure and perfusion.

22. Which condition most commonly leads to fluid volume excess?

Burns Heart failure Vomiting Diarrhea

Answer: Heart failure

Explanation: Heart failure causes fluid retention due to poor cardiac output and activation of the RAAS system.

23. Which laboratory value is likely increased in dehydration?

Hematocrit Sodium Albumin Potassium

Answer: Hematocrit

Explanation: Hemoconcentration during dehydration leads to increased hematocrit and hemoglobin levels.

24. What is the best indicator of fluid volume status?

Blood pressure Urine output Body weight Serum sodium

Answer: Body weight

Explanation: Daily weight changes are the most accurate, non-invasive measure of fluid gain or loss.

25. Which symptom indicates hypovolemia?

Bounding pulse Crackles in lungs Postural hypotension Jugular vein distension

Answer: Postural hypotension

Explanation: Postural hypotension is a drop in BP when standing, often seen in volume depletion.

26. Which hormone helps conserve water in hypovolemia?

ANP ADH Calcitonin Insulin

Answer: ADH

Explanation: Antidiuretic hormone increases water reabsorption in the kidneys during hypovolemia.

27. Which of the following is NOT a symptom of fluid overload?

Dyspnea Crackles Dry mucous membranes Hypertension

Answer: Dry mucous membranes

Explanation: Dry mucous membranes suggest dehydration, not fluid overload.

28. Fluid volume excess can cause which complication?

Renal stones Pulmonary edema Hypotension Bradycardia

Answer: Pulmonary edema

Explanation: Excess fluid can accumulate in the lungs, leading to pulmonary edema and respiratory distress.

29. What is the treatment for severe hypovolemia?

Diuretics Fluid restriction IV fluid replacement Sodium restriction

Answer: IV fluid replacement

Explanation: Rapid IV fluid replacement restores circulating volume in hypovolemia.

30. Which lab finding supports diagnosis of fluid overload?

Elevated hematocrit Decreased BUN High serum osmolality Hypernatremia

Answer: Decreased BUN

Explanation: Hemodilution in fluid overload may lower BUN and hematocrit values.

Category 4: Sodium Imbalance

31. What is the normal serum sodium level?

120–130 mEq/L 135–145 mEq/L 150–160 mEq/L 125–135 mEq/L

Answer: 135–145 mEq/L

Explanation: Normal sodium levels range from 135 to 145 mEq/L and are vital for nerve and muscle function.

32. What is a major cause of hyponatremia?

Dehydration Diuretic use Excess salt intake Kidney stones

Answer: Diuretic use

Explanation: Diuretics can increase sodium loss in urine, leading to hyponatremia.

33. Which symptom is most commonly associated with hyponatremia?

Hypertension Confusion Polyuria Bradycardia

Answer: Confusion

Explanation: Low sodium affects brain function, causing confusion, lethargy, and seizures.

34. What is the most dangerous complication of severe hyponatremia?

Cardiac arrest Cerebral edema Pulmonary edema Hypotension

Answer: Cerebral edema

Explanation: Severe hyponatremia can cause brain cells to swell, leading to cerebral edema and herniation.

35. What is a cause of hypernatremia?

Excess water intake Diabetes insipidus SIADH Heart failure

Answer: Diabetes insipidus

Explanation: Diabetes insipidus causes excessive water loss, leading to concentrated sodium in the blood.

36. Which symptom is consistent with hypernatremia?

Muscle cramps Thirst Bradycardia Increased urination

Answer: Thirst

Explanation: Thirst is an early and primary symptom of hypernatremia as the body tries to correct water imbalance.

37. What is the safest treatment for mild hypernatremia?

Rapid IV saline Diuretics Gradual oral water intake Glucose infusion

Answer: Gradual oral water intake

Explanation: Gradual replacement of free water prevents cerebral edema caused by too-rapid correction.

38. Which hormone is primarily responsible for sodium retention?

ADH Aldosterone Cortisol Renin

Answer: Aldosterone

Explanation: Aldosterone promotes sodium retention in the distal renal tubules to maintain fluid balance.

39. Which of the following can cause dilutional hyponatremia?

Excessive sweating Diabetic ketoacidosis Syndrome of inappropriate ADH (SIADH) Vomiting

Answer: Syndrome of inappropriate ADH (SIADH)

Explanation: SIADH causes water retention, diluting serum sodium concentration.

40. Which complication can occur if hypernatremia is corrected too rapidly?

Cerebral edema Renal failure Hypokalemia Cardiac arrhythmia

Answer: Cerebral edema

Explanation: Rapid correction of hypernatremia allows water to rush into brain cells, causing swelling and potentially fatal cerebral edema.

Category 5: Potassium Imbalance

41. What is the normal serum potassium range?

2.5–3.5 mEq/L 3.5–5.0 mEq/L 4.5–6.0 mEq/L 5.0–6.5 mEq/L

Answer: 3.5–5.0 mEq/L

Explanation: Potassium is essential for neuromuscular function and cardiac rhythm regulation.

42. Which condition is a common cause of hypokalemia?

Renal failure Diarrhea Burns SIADH

Answer: Diarrhea

Explanation: Potassium is lost through the GI tract in cases of diarrhea, leading to hypokalemia.

43. Which symptom is associated with hypokalemia?

Muscle weakness Bradycardia Tetany Seizures

Answer: Muscle weakness

Explanation: Hypokalemia impairs muscle function, often leading to generalized weakness and fatigue.

44. What is the ECG change seen in hypokalemia?

Peaked T waves U waves Prolonged QT interval ST elevation

Answer: U waves

Explanation: U waves are an ECG hallmark of hypokalemia, reflecting delayed ventricular repolarization.

45. What is a major risk of hypokalemia?

Seizures Cardiac arrhythmias Liver failure Hyperthermia

Answer: Cardiac arrhythmias

Explanation: Hypokalemia alters cardiac conduction, increasing the risk for dangerous arrhythmias.

46. Which food is highest in potassium?

Apple Banana Rice Cheese

Answer: Banana

Explanation: Bananas are rich in potassium and often recommended to correct or prevent hypokalemia.

47. What is the danger of IV potassium given too quickly?

Liver toxicity Cardiac arrest Respiratory alkalosis Skin necrosis

Answer: Cardiac arrest

Explanation: Rapid IV potassium can cause fatal cardiac arrhythmias or arrest; it must be diluted and infused slowly.

48. What is a key cause of hyperkalemia?

Diuretics Vomiting Renal failure Diarrhea

Answer: Renal failure

Explanation: The kidneys excrete potassium, so impaired function leads to accumulation and hyperkalemia.

49. What ECG change is typical in hyperkalemia?

Flattened T waves Peaked T waves U waves ST depression

Answer: Peaked T waves

Explanation: Peaked or tented T waves reflect early repolarization changes seen in hyperkalemia.

50. Which medication is used to lower potassium in emergencies?

Calcium gluconate Furosemide Kayexalate All of the above

Answer: All of the above

Explanation: Calcium gluconate protects the heart, furosemide increases excretion, and Kayexalate binds potassium in the gut.

Category 6: Calcium Imbalance

51. What is the normal serum calcium range?

6–8 mg/dL 8.5–10.5 mg/dL 11–13 mg/dL 4.5–5.5 mg/dL

Answer: 8.5–10.5 mg/dL

Explanation: Normal calcium is tightly regulated and essential for muscle contraction, blood clotting, and nerve transmission.

52. What is a common cause of hypocalcemia?

Hyperparathyroidism Vitamin D deficiency Immobilization Excess dairy intake

Answer: Vitamin D deficiency

Explanation: Vitamin D is needed for calcium absorption in the gut; its deficiency leads to hypocalcemia.

53. Which symptom is characteristic of hypocalcemia?

Muscle weakness Constipation Tetany Hypertension

Answer: Tetany

Explanation: Low calcium levels increase neuromuscular excitability, causing spasms and tetany.

54. Which sign indicates hypocalcemia?

Murphy's sign Trousseau's sign McBurney's sign Babinski sign

Answer: Trousseau's sign

Explanation: Trousseau's sign (carpal spasm with BP cuff inflation) is a classic indicator of hypocalcemia.

55. What is a typical ECG finding in hypocalcemia?

Shortened QT interval Prolonged QT interval Tall T wave U wave

Answer: Prolonged QT interval

Explanation: Hypocalcemia lengthens the ST segment and QT interval, increasing risk of arrhythmia.

56. What is the main hormone that increases serum calcium levels?

Calcitonin Parathyroid hormone (PTH) Insulin Cortisol

Answer: Parathyroid hormone (PTH)

Explanation: PTH increases calcium by stimulating bone resorption, kidney reabsorption, and activating vitamin D.

57. What is a common cause of hypercalcemia?

Hypoparathyroidism Renal failure Hyperparathyroidism SIADH

Answer: Hyperparathyroidism

Explanation: Overproduction of PTH increases calcium levels through bone resorption and kidney reabsorption.

58. Which symptom is associated with hypercalcemia?

Diarrhea Seizures Bone pain Muscle twitching

Answer: Bone pain

Explanation: High calcium levels from bone resorption may cause weakness and bone pain.

59. What ECG finding is typical in hypercalcemia?

Prolonged QT interval Peaked T waves Shortened QT interval ST elevation

Answer: Shortened QT interval

Explanation: Hypercalcemia shortens the repolarization phase, leading to a shorter QT interval.

60. Which intervention is appropriate for severe hypercalcemia?

Fluid restriction IV saline with loop diuretics Calcium supplements High calcium diet

Answer: IV saline with loop diuretics

Explanation: Hydration with saline promotes calcium excretion; loop diuretics (not thiazides) enhance renal loss.

Category 7: Magnesium Imbalance

61. What is the normal range of serum magnesium?

1.0–2.0 mg/dL 1.5–2.5 mg/dL 2.5–4.0 mg/dL 3.5–5.0 mg/dL

Answer: 1.5–2.5 mg/dL

Explanation: Normal serum magnesium levels are 1.5–2.5 mg/dL and are essential for enzyme function and neuromuscular activity.

62. Which condition commonly causes hypomagnesemia?

Renal failure Chronic alcoholism Hyperthyroidism Hypertension

Answer: Chronic alcoholism

Explanation: Chronic alcohol use leads to poor dietary intake and increased renal magnesium loss.

63. Which symptom is associated with hypomagnesemia?

Lethargy Muscle tremors Constipation Confusion

Answer: Muscle tremors

Explanation: Hypomagnesemia increases neuromuscular excitability, causing tremors, twitching, and seizures.

64. What ECG change is seen with hypomagnesemia?

Short QT interval Peaked T wave Prolonged QT interval ST elevation

Answer: Prolonged QT interval

Explanation: Hypomagnesemia can prolong the QT interval, increasing the risk of arrhythmias like torsades de pointes.

65. What is a primary cause of hypermagnesemia?

Chronic alcoholism Renal failure Diuretic use Malnutrition

Answer: Renal failure

Explanation: Impaired renal function reduces magnesium excretion, leading to accumulation and hypermagnesemia.

66. Which symptom is associated with hypermagnesemia?

Seizures Lethargy Muscle cramps Tachycardia

Answer: Lethargy

Explanation: High magnesium levels depress the nervous system, causing lethargy, weakness, and respiratory depression.

67. What is a treatment for hypermagnesemia?

Magnesium sulfate IV Calcium gluconate Potassium chloride Sodium bicarbonate

Answer: Calcium gluconate

Explanation: Calcium gluconate antagonizes magnesium's effects, stabilizing cardiac and neuromuscular function.

68. Which ECG change is seen in hypermagnesemia?

Peaked T waves Prolonged PR interval U waves Shortened QT interval

Answer: Prolonged PR interval

Explanation: Hypermagnesemia slows cardiac conduction, often causing a prolonged PR interval and bradycardia.

69. Which medication can contribute to hypomagnesemia?

ACE inhibitors Loop diuretics Beta-blockers Calcium channel blockers

Answer: Loop diuretics

Explanation: Loop diuretics increase magnesium excretion in urine, contributing to hypomagnesemia.

70. Which food is a good source of magnesium?

White bread Spinach Red meat Soda

Answer: Spinach

Explanation: Leafy greens like spinach are rich in magnesium, aiding in correcting deficiencies.

Category 8: Phosphate Imbalance

71. What is the normal serum phosphate range?

0.5–1.5 mg/dL 2.5–4.5 mg/dL 5.0–6.0 mg/dL 6.5–8.0 mg/dL

Answer: 2.5–4.5 mg/dL

Explanation: Phosphate is essential for bone health, energy production, and acid-base balance.

72. What is a common cause of hypophosphatemia?

Renal failure Alcoholism Hyperparathyroidism Hypothyroidism

Answer: Alcoholism

Explanation: Chronic alcoholism causes poor intake, malabsorption, and increased renal loss of phosphate.

73. Which symptom is associated with hypophosphatemia?

Muscle weakness Hypertension Seizures Bradycardia

Answer: Muscle weakness

Explanation: Low phosphate impairs ATP production, leading to muscle weakness and fatigue.

74. What is a cause of hyperphosphatemia?

Malnutrition Renal failure Diuretic use Diarrhea

Answer: Renal failure

Explanation: Impaired kidneys cannot excrete phosphate, leading to accumulation in the blood.

75. Which treatment is used for hyperphosphatemia?

Phosphate supplements Phosphate binders IV saline Vitamin D

Answer: Phosphate binders

Explanation: Phosphate binders reduce absorption of dietary phosphate in the gut, lowering serum levels.

76. Which hormone decreases serum phosphate levels?

Calcitonin Parathyroid hormone (PTH) Aldosterone ADH

Answer: Parathyroid hormone (PTH)

Explanation: PTH increases renal phosphate excretion, lowering serum phosphate levels.

77. Which condition is associated with hyperphosphatemia?

Hypoparathyroidism Hyperthyroidism Malnutrition Alcoholism

Answer: Hypoparathyroidism

Explanation: Low PTH reduces phosphate excretion, causing serum phosphate to rise.

78. What is a complication of severe hypophosphatemia?

Cardiac arrhythmias Renal stones Pulmonary edema Seizures

Answer: Cardiac arrhythmias

Explanation: Severe hypophosphatemia impairs cardiac function, increasing arrhythmia risk due to low ATP.

79. Which food is high in phosphate?

Bananas Dairy products White rice Apples

Answer: Dairy products

Explanation: Dairy products like milk and cheese are rich in phosphate, aiding in deficiency correction.

80. What is a risk of rapid phosphate correction?

Hypocalcemia Hyperkalemia Hypomagnesemia Hypernatremia

Answer: Hypocalcemia

Explanation: Rapid phosphate infusion can bind calcium, causing hypocalcemia and related complications.

Category 9: Acid-Base Balance

81. What is the normal arterial blood pH range?

7.25–7.35 7.35–7.45 7.45–7.55 7.15–7.25

Answer: 7.35–7.45

Explanation: Normal arterial pH is tightly regulated to maintain homeostasis and support metabolic functions.

82. Which condition causes metabolic acidosis?

Hyperventilation Diabetic ketoacidosis Vomiting Hypoventilation

Answer: Diabetic ketoacidosis

Explanation: DKA produces excess ketones, lowering blood pH and causing metabolic acidosis.

83. What is a compensatory mechanism for metabolic acidosis?

Hypoventilation Hyperventilation Increased urine output Sodium retention

Answer: Hyperventilation

Explanation: The lungs compensate by exhaling more CO2, reducing carbonic acid and raising pH.

84. Which condition leads to respiratory acidosis?

Anxiety COPD Fever Aspirin overdose

Answer: COPD

Explanation: Chronic obstructive pulmonary disease causes CO2 retention, increasing carbonic acid and lowering pH.

85. What is a hallmark sign of respiratory acidosis?

Tachypnea Hyperventilation Hypoventilation Polyuria

Answer: Hypoventilation

Explanation: Hypoventilation reduces CO2 exhalation, leading to acid accumulation and respiratory acidosis.

86. Which condition causes metabolic alkalosis?

Diarrhea Prolonged vomiting Renal failure Hypoventilation

Answer: Prolonged vomiting

Explanation: Vomiting causes loss of HCl, increasing blood pH and leading to metabolic alkalosis.

87. What compensates for respiratory alkalosis?

Increased CO2 retention Increased bicarbonate excretion Sodium retention Potassium excretion

Answer: Increased bicarbonate excretion

Explanation: Kidneys excrete bicarbonate to lower pH in response to low CO2 from hyperventilation.

88. Which lab value indicates metabolic acidosis?

Low pH, low bicarbonate High pH, high bicarbonate Low pH, high PCO2 High pH, low PCO2

Answer: Low pH, low bicarbonate

Explanation: Metabolic acidosis is marked by low pH and reduced bicarbonate due to acid accumulation.

89. Which condition causes respiratory alkalosis?

Pneumonia Anxiety-induced hyperventilation COPD Pulmonary edema

Answer: Anxiety-induced hyperventilation

Explanation: Hyperventilation reduces CO2, decreasing carbonic acid and raising pH.

90. What is a treatment for metabolic alkalosis?

Sodium bicarbonate Ammonium chloride Loop diuretics Hyperventilation

Answer: Ammonium chloride

Explanation: Ammonium chloride provides acid to correct the excess base in metabolic alkalosis.

Category 10: Clinical Applications

91. Which IV fluid is isotonic and used for fluid replacement?

D5W 0.9% NaCl 3% NaCl 0.45% NaCl

Answer: 0.9% NaCl

Explanation: Normal saline (0.9% NaCl) is isotonic, ideal for restoring intravascular volume without shifting fluids.

92. Which electrolyte imbalance is a risk with rapid IV saline infusion?

Hypokalemia Hypernatremia Hypocalcemia Hypermagnesemia

Answer: Hypernatremia

Explanation: Rapid infusion of 0.9% NaCl can increase sodium levels, risking hypernatremia if not monitored.

93. Which assessment is critical before administering IV potassium?

Blood pressure Urine output Heart rate Respiratory rate

Answer: Urine output

Explanation: Adequate renal function (urine output) is essential to prevent hyperkalemia during potassium infusion.

94. Which condition requires careful fluid restriction?

Dehydration SIADH Burns Hemorrhage

Answer: SIADH

Explanation: SIADH causes water retention, so fluid restriction is used to prevent dilutional hyponatremia.

95. What is a priority nursing action for a patient with hyperkalemia?

Administer insulin Monitor ECG Encourage oral fluids Restrict sodium

Answer: Monitor ECG

Explanation: Hyperkalemia can cause life-threatening arrhythmias, making ECG monitoring critical.

96. What is the treatment for severe hyponatremia?

D5W 0.45% NaCl 3% NaCl Lactated Ringer's

Answer: 3% NaCl

Explanation: Hypertonic 3% NaCl is used cautiously to correct severe hyponatremia, preventing rapid fluid shifts.

97. Which electrolyte imbalance is a risk with prolonged nasogastric suction?

Hyperkalemia Hypomagnesemia Hypercalcemia Hyponatremia

Answer: Hyponatremia

Explanation: NG suction removes sodium-rich gastric fluid, increasing the risk of hyponatremia.

98. Which symptom indicates severe hypocalcemia in a postoperative patient?

Bradycardia Laryngeal spasm Hypertension Lethargy

Answer: Laryngeal spasm

Explanation: Severe hypocalcemia can cause life-threatening laryngeal spasms.

99. Which lab value should be monitored during diuretic therapy?

Serum sodium Serum potassium Serum calcium All of the above

Answer: All of the above

Explanation: Diuretics can alter sodium, potassium, and calcium levels, requiring comprehensive monitoring.

100. What is the priority action for a patient with suspected fluid overload?

Administer IV fluids Assess lung sounds Encourage ambulation Measure blood pressure

Answer: Assess lung sounds

Explanation: Lung sounds can reveal crackles indicating pulmonary edema, a critical complication of fluid overload.