ATI Fluid, Electrolyte & Acid-Base Proctored Exam | 2026/2027
ATI FLUID, ELECTROLYTE, AND
ACID-BASE PROCTORED EXAM
2026/2027 Edition
NCLEX-RN Readiness Assessment
ATI Nursing Education
Comprehensive Questions with Verified Answers
110 Questions | Graded A+
Academic Year 2026-2027
Page 1
, ATI Fluid, Electrolyte & Acid-Base Proctored Exam | 2026/2027
Table of Contents
Section 1: Acid-Base Disorders & ABG Interpretation
Section 2: Sodium Imbalances (Hyponatremia / Hypernatremia)
Section 3: Potassium Imbalances (Hypokalemia / Hyperkalemia)
Section 4: Calcium Imbalances (Hypocalcemia / Hypercalcemia)
Section 5: Magnesium & Phosphorus Imbalances
Section 6: IV Fluid Therapy (Isotonic, Hypotonic, Hypertonic)
Section 7: Electrolyte Replacement & Pharmacologic Management
Section 8: Priority Nursing Interventions & Safety
Section 9: Patient Education & Prevention Strategies
Section 10: NGN-Style Case Scenarios & Integrated Questions
Page 2
, ATI Fluid, Electrolyte & Acid-Base Proctored Exam | 2026/2027
Section 1: Acid-Base Disorders & ABG Interpretation
1. A patient presents with pH 7.30, PaCO₂ 50 mmHg, HCO₃⁻ 24 mEq/L. What is the acid-base
disorder?
A. Uncompensated respiratory acidosis
B. Partially compensated respiratory acidosis
C. Uncompensated metabolic acidosis
D. Fully compensated respiratory acidosis
Rationale: Low pH (7.30 < 7.35) indicates acidosis. Elevated PaCO₂ (50 > 45) indicates
a respiratory cause. Normal HCO₃⁻ (24 within 22-26) indicates the kidneys have not yet
compensated. This is uncompensated respiratory acidosis, commonly caused by
hypoventilation from COPD, pneumonia, or opioid overdose.
2. What does the ROME mnemonic indicate for acid-base interpretation?
A. Respiratory Opposite, Metabolic Equal
B. Respiratory Originates, Metabolic Eliminates
C. Respiratory Out, Metabolic Exchange
D. Respiratory Overcompensates, Metabolic Undercompensates
Rationale: The ROME mnemonic states: Respiratory Opposite (pH and PaCO₂ move in
opposite directions) and Metabolic Equal (pH and HCO₃⁻ move in the same direction).
When pH is low and PaCO₂ is high, it is respiratory acidosis. When pH is low and HCO₃⁻
is low, it is metabolic acidosis. This is the foundation of ABG interpretation.
3. Which ABG values indicate uncompensated metabolic alkalosis?
A. pH 7.50, PaCO₂ 45, HCO₃⁻ 32
B. pH 7.48, PaCO₂ 48, HCO₃⁻ 30
C. pH 7.32, PaCO₂ 30, HCO₃⁻ 18
D. pH 7.50, PaCO₂ 50, HCO₃⁻ 26
Rationale: pH 7.50 (> 7.45) indicates alkalosis. HCO₃⁻ 32 (> 26) elevated in the same
direction as pH, indicating a metabolic cause per the ROME mnemonic. PaCO₂ 45 is
within normal range (35-45), indicating no respiratory compensation has occurred yet.
This pattern is seen with vomiting, NG suction, or diuretic therapy.
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, ATI Fluid, Electrolyte & Acid-Base Proctored Exam | 2026/2027
4. A patient with DKA has the following ABG: pH 7.25, PaCO₂ 30, HCO₃⁻ 16. What is the acid-
base interpretation?
A. Uncompensated metabolic acidosis
B. Partially compensated metabolic acidosis
C. Uncompensated respiratory alkalosis
D. Fully compensated metabolic acidosis
Rationale: Low pH (7.25 < 7.35) indicates acidosis. Low HCO₃⁻ (16 < 22) indicates
metabolic cause (ROME: pH and HCO₃⁻ move together). Low PaCO₂ (30 < 35) indicates
the lungs are compensating by blowing off CO₂. Since pH is still abnormal (not
normalized), this is partially compensated metabolic acidosis, consistent with DKA
causing ketone accumulation.
5. A patient with anxiety attacks is hyperventilating. What ABG pattern is expected?
A. pH 7.32, PaCO₂ 50, HCO₃⁻ 24
B. pH 7.50, PaCO₂ 30, HCO₃⁻ 24
C. pH 7.30, PaCO₂ 25, HCO₃⁻ 18
D. pH 7.48, PaCO₂ 48, HCO₃⁻ 30
Rationale: Hyperventilation causes excessive CO₂ elimination, leading to respiratory
alkalosis: high pH (> 7.45) with low PaCO₂ (< 35). The HCO₃⁻ remains normal (24)
because metabolic compensation takes days to develop through renal mechanisms. This
is uncompensated respiratory alkalosis. Treatment involves addressing the underlying
cause (anxiety, pain, fever).
6. What ABG pattern indicates fully compensated respiratory acidosis?
A. pH 7.30, PaCO₂ 55, HCO₃⁻ 24
B. pH 7.38, PaCO₂ 55, HCO₃⁻ 32
C. pH 7.48, PaCO₂ 30, HCO₃⁻ 20
D. pH 7.35, PaCO₂ 35, HCO₃⁻ 22
Page 4
ATI FLUID, ELECTROLYTE, AND
ACID-BASE PROCTORED EXAM
2026/2027 Edition
NCLEX-RN Readiness Assessment
ATI Nursing Education
Comprehensive Questions with Verified Answers
110 Questions | Graded A+
Academic Year 2026-2027
Page 1
, ATI Fluid, Electrolyte & Acid-Base Proctored Exam | 2026/2027
Table of Contents
Section 1: Acid-Base Disorders & ABG Interpretation
Section 2: Sodium Imbalances (Hyponatremia / Hypernatremia)
Section 3: Potassium Imbalances (Hypokalemia / Hyperkalemia)
Section 4: Calcium Imbalances (Hypocalcemia / Hypercalcemia)
Section 5: Magnesium & Phosphorus Imbalances
Section 6: IV Fluid Therapy (Isotonic, Hypotonic, Hypertonic)
Section 7: Electrolyte Replacement & Pharmacologic Management
Section 8: Priority Nursing Interventions & Safety
Section 9: Patient Education & Prevention Strategies
Section 10: NGN-Style Case Scenarios & Integrated Questions
Page 2
, ATI Fluid, Electrolyte & Acid-Base Proctored Exam | 2026/2027
Section 1: Acid-Base Disorders & ABG Interpretation
1. A patient presents with pH 7.30, PaCO₂ 50 mmHg, HCO₃⁻ 24 mEq/L. What is the acid-base
disorder?
A. Uncompensated respiratory acidosis
B. Partially compensated respiratory acidosis
C. Uncompensated metabolic acidosis
D. Fully compensated respiratory acidosis
Rationale: Low pH (7.30 < 7.35) indicates acidosis. Elevated PaCO₂ (50 > 45) indicates
a respiratory cause. Normal HCO₃⁻ (24 within 22-26) indicates the kidneys have not yet
compensated. This is uncompensated respiratory acidosis, commonly caused by
hypoventilation from COPD, pneumonia, or opioid overdose.
2. What does the ROME mnemonic indicate for acid-base interpretation?
A. Respiratory Opposite, Metabolic Equal
B. Respiratory Originates, Metabolic Eliminates
C. Respiratory Out, Metabolic Exchange
D. Respiratory Overcompensates, Metabolic Undercompensates
Rationale: The ROME mnemonic states: Respiratory Opposite (pH and PaCO₂ move in
opposite directions) and Metabolic Equal (pH and HCO₃⁻ move in the same direction).
When pH is low and PaCO₂ is high, it is respiratory acidosis. When pH is low and HCO₃⁻
is low, it is metabolic acidosis. This is the foundation of ABG interpretation.
3. Which ABG values indicate uncompensated metabolic alkalosis?
A. pH 7.50, PaCO₂ 45, HCO₃⁻ 32
B. pH 7.48, PaCO₂ 48, HCO₃⁻ 30
C. pH 7.32, PaCO₂ 30, HCO₃⁻ 18
D. pH 7.50, PaCO₂ 50, HCO₃⁻ 26
Rationale: pH 7.50 (> 7.45) indicates alkalosis. HCO₃⁻ 32 (> 26) elevated in the same
direction as pH, indicating a metabolic cause per the ROME mnemonic. PaCO₂ 45 is
within normal range (35-45), indicating no respiratory compensation has occurred yet.
This pattern is seen with vomiting, NG suction, or diuretic therapy.
Page 3
, ATI Fluid, Electrolyte & Acid-Base Proctored Exam | 2026/2027
4. A patient with DKA has the following ABG: pH 7.25, PaCO₂ 30, HCO₃⁻ 16. What is the acid-
base interpretation?
A. Uncompensated metabolic acidosis
B. Partially compensated metabolic acidosis
C. Uncompensated respiratory alkalosis
D. Fully compensated metabolic acidosis
Rationale: Low pH (7.25 < 7.35) indicates acidosis. Low HCO₃⁻ (16 < 22) indicates
metabolic cause (ROME: pH and HCO₃⁻ move together). Low PaCO₂ (30 < 35) indicates
the lungs are compensating by blowing off CO₂. Since pH is still abnormal (not
normalized), this is partially compensated metabolic acidosis, consistent with DKA
causing ketone accumulation.
5. A patient with anxiety attacks is hyperventilating. What ABG pattern is expected?
A. pH 7.32, PaCO₂ 50, HCO₃⁻ 24
B. pH 7.50, PaCO₂ 30, HCO₃⁻ 24
C. pH 7.30, PaCO₂ 25, HCO₃⁻ 18
D. pH 7.48, PaCO₂ 48, HCO₃⁻ 30
Rationale: Hyperventilation causes excessive CO₂ elimination, leading to respiratory
alkalosis: high pH (> 7.45) with low PaCO₂ (< 35). The HCO₃⁻ remains normal (24)
because metabolic compensation takes days to develop through renal mechanisms. This
is uncompensated respiratory alkalosis. Treatment involves addressing the underlying
cause (anxiety, pain, fever).
6. What ABG pattern indicates fully compensated respiratory acidosis?
A. pH 7.30, PaCO₂ 55, HCO₃⁻ 24
B. pH 7.38, PaCO₂ 55, HCO₃⁻ 32
C. pH 7.48, PaCO₂ 30, HCO₃⁻ 20
D. pH 7.35, PaCO₂ 35, HCO₃⁻ 22
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