ATI Pediatrics | Pediatric Fluid & Electrolyte Imbalances Practice Pack
2026/2027 Questions |Answers |Rationales
1. A 10-month-old infant is admitted with severe diarrhea. Which assessment
finding should the nurse prioritize as a sign of severe dehydration?
A. Tachycardia and bradypnea
B. Sunken fontanels and dry mucous membranes
C. Lethargy and hypotension
D. Capillary refill of 2 seconds
Answer: C
Rationale: Severe dehydration in infants is characterized by signs of shock, such as
hypotension, lethargy, and significantly delayed capillary refill.
2. When calculating the daily maintenance fluid requirement for a child
weighing 15 kg, what is the correct volume?
A. 1,250 mL
B. 1,000 mL
C. 1,500 mL
D. 750 mL
Answer: A
Rationale: Using the Holliday-Segar method: 100 mL/kg for the first 10 kg (1000 mL) + 50
mL/kg for the next 5 kg (250 mL) = 1,250 mL.
,3. A child is diagnosed with isotonic dehydration. Which of the following IV
fluids is most appropriate for initial bolus rehydration?
A. 0.45% Sodium Chloride
B. 5% Dextrose in Water (D5W)
C. 0.9% Sodium Chloride (Normal Saline)
D. D5 0.225% Sodium Chloride
Answer: C
Rationale: Isotonic solutions like 0.9% NaCl or Lactated Ringer’s are used for rapid volume
expansion in dehydration.
4. Which electrolyte imbalance is a nurse most likely to observe in a child with
prolonged vomiting due to pyloric stenosis?
A. Hyperkalemia
B. Metabolic acidosis
C. Hypernatremia
D. Hypochloremia
Answer: D
Rationale: Vomiting results in the loss of gastric hydrochloric acid, leading to
hypochloremia and metabolic alkalosis.
5. A school-age child has a serum potassium level of 6.2 mEq/L. Which of the
following is the priority nursing action?
A. Obtain an electrocardiogram (ECG)
B. Encourage intake of bananas
C. Administer a potassium supplement
D. Re-draw the lab in 4 hours
Answer: A
Rationale: Hyperkalemia (K > 5.5) can cause life-threatening cardiac arrhythmias.
Assessing cardiac rhythm via ECG is the priority.
, 6. What is the minimum recommended urine output for an infant weighing 8
kg?
A. 5 mL/hr
B. 8 mL/hr
C. 24 mL/hr
D. 16 mL/hr
Answer: D
Rationale: The minimum urine output for infants and toddlers is 2 mL/kg/hr. For an 8 kg
infant, 8 x 2 = 16 mL/hr.
7. A child presents with a serum sodium level of 128 mEq/L. Which symptom is
the nurse most likely to observe?
A. Increased thirst
B. Seizures
C. Sticky mucous membranes
D. Peripheral edema
Answer: B
Rationale: Hyponatremia (Na < 135) can cause cerebral edema, leading to neurological
symptoms like seizures, confusion, and lethargy.
8. A nurse is caring for a child with metabolic acidosis. Which compensatory
mechanism should the nurse expect to see?
A. Increased urinary pH
B. Hypoventilation
C. Kussmaul respirations
D. Bradycardia
Answer: C
Rationale: In metabolic acidosis, the lungs compensate by increasing the rate and depth of
respirations (Kussmaul) to blow off CO2.
2026/2027 Questions |Answers |Rationales
1. A 10-month-old infant is admitted with severe diarrhea. Which assessment
finding should the nurse prioritize as a sign of severe dehydration?
A. Tachycardia and bradypnea
B. Sunken fontanels and dry mucous membranes
C. Lethargy and hypotension
D. Capillary refill of 2 seconds
Answer: C
Rationale: Severe dehydration in infants is characterized by signs of shock, such as
hypotension, lethargy, and significantly delayed capillary refill.
2. When calculating the daily maintenance fluid requirement for a child
weighing 15 kg, what is the correct volume?
A. 1,250 mL
B. 1,000 mL
C. 1,500 mL
D. 750 mL
Answer: A
Rationale: Using the Holliday-Segar method: 100 mL/kg for the first 10 kg (1000 mL) + 50
mL/kg for the next 5 kg (250 mL) = 1,250 mL.
,3. A child is diagnosed with isotonic dehydration. Which of the following IV
fluids is most appropriate for initial bolus rehydration?
A. 0.45% Sodium Chloride
B. 5% Dextrose in Water (D5W)
C. 0.9% Sodium Chloride (Normal Saline)
D. D5 0.225% Sodium Chloride
Answer: C
Rationale: Isotonic solutions like 0.9% NaCl or Lactated Ringer’s are used for rapid volume
expansion in dehydration.
4. Which electrolyte imbalance is a nurse most likely to observe in a child with
prolonged vomiting due to pyloric stenosis?
A. Hyperkalemia
B. Metabolic acidosis
C. Hypernatremia
D. Hypochloremia
Answer: D
Rationale: Vomiting results in the loss of gastric hydrochloric acid, leading to
hypochloremia and metabolic alkalosis.
5. A school-age child has a serum potassium level of 6.2 mEq/L. Which of the
following is the priority nursing action?
A. Obtain an electrocardiogram (ECG)
B. Encourage intake of bananas
C. Administer a potassium supplement
D. Re-draw the lab in 4 hours
Answer: A
Rationale: Hyperkalemia (K > 5.5) can cause life-threatening cardiac arrhythmias.
Assessing cardiac rhythm via ECG is the priority.
, 6. What is the minimum recommended urine output for an infant weighing 8
kg?
A. 5 mL/hr
B. 8 mL/hr
C. 24 mL/hr
D. 16 mL/hr
Answer: D
Rationale: The minimum urine output for infants and toddlers is 2 mL/kg/hr. For an 8 kg
infant, 8 x 2 = 16 mL/hr.
7. A child presents with a serum sodium level of 128 mEq/L. Which symptom is
the nurse most likely to observe?
A. Increased thirst
B. Seizures
C. Sticky mucous membranes
D. Peripheral edema
Answer: B
Rationale: Hyponatremia (Na < 135) can cause cerebral edema, leading to neurological
symptoms like seizures, confusion, and lethargy.
8. A nurse is caring for a child with metabolic acidosis. Which compensatory
mechanism should the nurse expect to see?
A. Increased urinary pH
B. Hypoventilation
C. Kussmaul respirations
D. Bradycardia
Answer: C
Rationale: In metabolic acidosis, the lungs compensate by increasing the rate and depth of
respirations (Kussmaul) to blow off CO2.
