Acid-Base Balance NCLEX Practice Questions PDF

**Acid-Base Balance NCLEX Practice Questions** Each question includes four answer choices, with one correct answer and a rationale. **General Acid-Base Concepts** 1. **Which of the following best describes the role of acids in the body?** - A\) Accepts H+ and raises pH - B\) Pr...

**Acid-Base Balance NCLEX Practice Questions** Each question includes four answer choices, with one correct answer and a rationale. **General Acid-Base Concepts** 1. **Which of the following best describes the role of acids in the body?** - A\) Accepts H+ and raises pH - B\) Produces H+ and lowers pH - C\) Neutralizes bases and maintains a high pH - D\) Prevents metabolic compensation - **Answer:** B) Produces H+ and lowers pH - **Rationale:** Acids donate hydrogen ions (H+), which decreases pH, making the environment more acidic. 2. **What is the normal pH range of arterial blood?** - A\) 6.8 -- 7.2 - B\) 7.0 -- 7.5 - C\) 7.35 -- 7.45 - D\) 7.5 -- 7.8 - **Answer:** C) 7.35 -- 7.45 - **Rationale:** The normal pH of arterial blood falls within this range, maintaining homeostasis. 3. **Which organ system primarily regulates bicarbonate (HCO3-)?** - A\) Respiratory system - B\) Renal system - C\) Digestive system - D\) Lymphatic system - **Answer:** B) Renal system - **Rationale:** The kidneys regulate bicarbonate (HCO3-) levels, which affect metabolic acid-base balance. **Respiratory Acidosis** 4. **A patient presents with hypoventilation, dizziness, and muscle twitching. ABG results show a low pH and high PaCO2. What is the likely diagnosis?** - A\) Respiratory acidosis - B\) Respiratory alkalosis - C\) Metabolic acidosis - D\) Metabolic alkalosis - **Answer:** A) Respiratory acidosis - **Rationale:** Hypoventilation leads to CO2 retention, increasing carbonic acid and lowering pH. 5. **Which of the following is a likely cause of respiratory acidosis?** - A\) Panic attack - B\) Chronic obstructive pulmonary disease (COPD) - C\) Prolonged vomiting - D\) Diabetic ketoacidosis - **Answer:** B) Chronic obstructive pulmonary disease (COPD) - **Rationale:** COPD causes hypoventilation and CO2 retention, leading to respiratory acidosis. 6. **Which intervention is most appropriate for a patient with respiratory acidosis?** - A\) Encourage hyperventilation - B\) Administer sodium bicarbonate - C\) Maintain a patent airway and provide oxygen cautiously - D\) Restrict fluid intake - **Answer:** C) Maintain a patent airway and provide oxygen cautiously - **Rationale:** Oxygen must be given cautiously in patients with chronic respiratory acidosis to avoid suppressing respiratory drive. **Respiratory Alkalosis** 7. **Which condition is most likely to result in respiratory alkalosis?** - A\) Diabetic ketoacidosis - B\) Renal failure - C\) Hyperventilation due to anxiety - D\) Severe dehydration - **Answer:** C) Hyperventilation due to anxiety - **Rationale:** Hyperventilation leads to excessive CO2 elimination, increasing pH. 8. **A patient experiencing respiratory alkalosis may exhibit which symptom?** - A\) Bradycardia - B\) Muscle twitching - C\) Tingling of extremities - D\) Kussmaul respirations - **Answer:** C) Tingling of extremities - **Rationale:** Hypocapnia (low CO2) can cause tingling, numbness, and tetany. 9. **A patient experiencing hyperventilation is advised to:** - A\) Take deep, slow breaths - B\) Breathe into a paper bag - C\) Increase fluid intake - D\) Lay flat on their back - **Answer:** B) Breathe into a paper bag - **Rationale:** Rebreathing exhaled CO2 helps correct respiratory alkalosis. **Metabolic Acidosis** 10. **Which of the following conditions can lead to metabolic acidosis?** - A\) COPD - B\) Kidney failure - C\) Panic attack - D\) NG suction - **Answer:** B) Kidney failure - **Rationale:** The kidneys fail to excrete H+, leading to metabolic acidosis. 11. **What is a hallmark sign of metabolic acidosis?** - A\) Shallow breathing - B\) Kussmaul respirations - C\) Decreased anion gap - D\) Bradycardia - **Answer:** B) Kussmaul respirations - **Rationale:** Kussmaul respirations are deep, rapid breaths that help eliminate CO2. 12. **A nurse is reviewing a patient's ABG results: pH 7.30, HCO3- 18, PaCO2 35. What is the diagnosis?** - A\) Respiratory acidosis - B\) Respiratory alkalosis - C\) Metabolic acidosis - D\) Metabolic alkalosis - **Answer:** C) Metabolic acidosis - **Rationale:** Low pH and low HCO3- indicate metabolic acidosis. **Metabolic Alkalosis** 13. **A patient with prolonged vomiting is at risk for which acid-base imbalance?** - A\) Respiratory acidosis - B\) Respiratory alkalosis - C\) Metabolic acidosis - D\) Metabolic alkalosis - **Answer:** D) Metabolic alkalosis - **Rationale:** Vomiting leads to loss of gastric acid, increasing pH. 14. **Which electrolyte imbalance is commonly associated with metabolic alkalosis?** - A\) Hyperkalemia - B\) Hypokalemia - C\) Hypernatremia - D\) Hypercalcemia - **Answer:** B) Hypokalemia - **Rationale:** Hydrogen ions shift into cells, leading to a decrease in serum potassium. 15. **A nurse is monitoring a patient with metabolic alkalosis. Which finding requires immediate intervention?** - A\) Muscle cramps - B\) Confusion - C\) Seizures - D\) Tingling in extremities - **Answer:** C) Seizures - **Rationale:** Severe alkalosis can cause neuromuscular excitability, increasing seizure risk. **Acid-Base Regulation & Compensation** 16. **Which system is the fastest in responding to acid-base imbalances?** - A\) Renal system - B\) Cardiovascular system - C\) Respiratory system - D\) Endocrine system - **Answer:** C) Respiratory system - **Rationale:** The respiratory system responds within minutes by adjusting CO₂ levels. 17. **A patient has an ABG result of pH 7.31, PaCO₂ 50, HCO₃⁻ 25. What type of imbalance is this?** - A\) Respiratory alkalosis - B\) Respiratory acidosis - C\) Metabolic acidosis - D\) Metabolic alkalosis - **Answer:** B) Respiratory acidosis - **Rationale:** Low pH and high PaCO₂ indicate respiratory acidosis. 18. **Which of the following ABG results suggest fully compensated metabolic acidosis?** - A\) pH 7.40, PaCO₂ 32, HCO₃⁻ 18 - B\) pH 7.30, PaCO₂ 50, HCO₃⁻ 24 - C\) pH 7.48, PaCO₂ 37, HCO₃⁻ 30 - D\) pH 7.27, PaCO₂ 33, HCO₃⁻ 17 - **Answer:** A) pH 7.40, PaCO₂ 32, HCO₃⁻ 18 - **Rationale:** A normal pH with abnormal PaCO₂ and HCO₃⁻ indicates full compensation. 19. **In metabolic acidosis, how does the body compensate?** - A\) Increasing bicarbonate excretion - B\) Decreasing respiratory rate - C\) Increasing CO₂ retention - D\) Increasing respiratory rate - **Answer:** D) Increasing respiratory rate - **Rationale:** The respiratory system compensates by eliminating CO₂ via hyperventilation. 20. **A patient's ABG values are pH 7.52, PaCO₂ 30, HCO₃⁻ 22. What is the interpretation?** - A\) Respiratory alkalosis - B\) Metabolic alkalosis - C\) Metabolic acidosis - D\) Respiratory acidosis - **Answer:** A) Respiratory alkalosis - **Rationale:** High pH and low PaCO₂ indicate respiratory alkalosis. **Respiratory Acidosis** 21. **A nurse is caring for a patient with respiratory acidosis. Which electrolyte imbalance should be monitored?** - A\) Hypokalemia - B\) Hyperkalemia - C\) Hypocalcemia - D\) Hypernatremia - **Answer:** B) Hyperkalemia - **Rationale:** Acidosis causes potassium to shift out of cells, increasing serum K⁺. 22. **Which of the following can lead to respiratory acidosis?** - A\) Anxiety - B\) Severe asthma - C\) Hyperventilation - D\) Excessive vomiting - **Answer:** B) Severe asthma - **Rationale:** Airway obstruction prevents CO₂ elimination, leading to acidosis. 23. **A patient with respiratory acidosis should be assessed for:** - A\) Hyperventilation - B\) Hypotension - C\) Muscle twitching - D\) Both B and C - **Answer:** D) Both B and C - **Rationale:** Hypoventilation increases CO₂, leading to decreased oxygenation and neuromuscular symptoms. **Respiratory Alkalosis** 24. **Which of the following is a priority intervention for respiratory alkalosis?** - A\) Increase oxygen delivery - B\) Have the patient breathe into a paper bag - C\) Administer sodium bicarbonate - D\) Encourage rapid breathing - **Answer:** B) Have the patient breathe into a paper bag - **Rationale:** Rebreathing CO₂ helps correct alkalosis caused by hyperventilation. 25. **A nurse assesses a patient with respiratory alkalosis. What symptom is expected?** - A\) Lethargy - B\) Muscle cramping - C\) Kussmaul respirations - D\) Bradypnea - **Answer:** B) Muscle cramping - **Rationale:** Alkalosis increases neuromuscular excitability, leading to cramps. **Metabolic Acidosis** 26. **Which of the following causes metabolic acidosis?** - A\) COPD - B\) Hyperventilation - C\) Diabetic ketoacidosis (DKA) - D\) Excessive antacid use - **Answer:** C) Diabetic ketoacidosis (DKA) - **Rationale:** DKA leads to excess acid accumulation. 27. **A patient with metabolic acidosis is likely to experience:** - A\) Kussmaul respirations - B\) Slow, shallow breathing - C\) Hypertension - D\) Decreased potassium levels - **Answer:** A) Kussmaul respirations - **Rationale:** Deep, rapid breathing compensates for acidosis. **Metabolic Alkalosis** 28. **Which condition increases the risk of metabolic alkalosis?** - A\) Renal failure - B\) Diarrhea - C\) Prolonged vomiting - D\) DKA - **Answer:** C) Prolonged vomiting - **Rationale:** Vomiting results in H⁺ loss, increasing pH. 29. **Which assessment finding is associated with metabolic alkalosis?** - A\) Hyperventilation - B\) Decreased LOC - C\) Bradycardia - D\) Increased urine acidity - **Answer:** B) Decreased LOC - **Rationale:** Alkalosis can decrease cerebral blood flow, leading to confusion. **Arterial Blood Gas (ABG) Analysis** 30. **What is the normal range for PaCO₂?** - A\) 22 -- 26 mmHg - B\) 35 -- 45 mmHg - C\) 80 -- 100 mmHg - D\) 50 -- 60 mmHg - **Answer:** B) 35 -- 45 mmHg 31. **Which ABG value primarily reflects metabolic function?** - A\) PaCO₂ - B\) HCO₃⁻ - C\) pH - D\) PaO₂ - **Answer:** B) HCO₃⁻ 32. **Which ABG value is most affected in respiratory conditions?** - A\) HCO₃⁻ - B\) PaCO₂ - C\) pH - D\) PaO₂ - **Answer:** B) PaCO₂ **Mixed Acid-Base Disorders** 33. **A patient with severe diarrhea is at risk for which imbalance?** - A\) Metabolic acidosis - B\) Metabolic alkalosis - C\) Respiratory acidosis - D\) Respiratory alkalosis - **Answer:** A) Metabolic acidosis 34. **A patient has a pH of 7.28, PaCO₂ of 55, and HCO₃⁻ of 20. How would you classify the imbalance?** - A\) Uncompensated Respiratory acidosis - B\) Uncompensated Metabolic acidosis - C\) Fully Compensated respiratory acidosis - D\) Partially Compensated respiratory acidosis - **Answer:** D) Partially Compensated respiratory acidosis 35. **Which compensatory mechanism occurs in response to metabolic alkalosis?** - A\) Increased CO₂ exhalation - B\) Hypoventilation - C\) Increased renal bicarbonate excretion - D\) Hyperventilation - **Answer:** B) Hypoventilation - **Rationale:** Hypoventilation retains CO₂, decreasing pH to compensate for alkalosis. 36. **Which of the following is an example of a mixed acid-base disorder?** - A\) COPD and vomiting - B\) Hyperventilation and metabolic acidosis - C\) Diarrhea and metabolic alkalosis - D\) Hyperkalemia and respiratory alkalosis - **Answer:** A) COPD and vomiting - **Rationale:** COPD causes respiratory acidosis, while vomiting leads to metabolic alkalosis. 37. **In an uncompensated acid-base imbalance, which value remains within the normal range?** - A\) pH - B\) PaCO₂ - C\) HCO₃⁻ - D\) Either PaCO₂ or HCO₃⁻, depending on the disorder - **Answer:** D) Either PaCO₂ or HCO₃⁻, depending on the disorder - **Rationale:** In uncompensated imbalances, one of the buffer systems has not yet responded. **Respiratory Acidosis** 38. **Which of the following is a long-term effect of untreated respiratory acidosis?** - A\) Hyperkalemia - B\) Increased bone density - C\) Muscle hyperexcitability - D\) Increased renal excretion of bicarbonate - **Answer:** A) Hyperkalemia - **Rationale:** Acidosis causes potassium to shift out of cells, leading to hyperkalemia. 39. **What is a key difference between acute and chronic respiratory acidosis?** - A\) Chronic respiratory acidosis has a normal bicarbonate level - B\) Acute respiratory acidosis is partially compensated - C\) Chronic respiratory acidosis is fully compensated - D\) Acute respiratory acidosis leads to a decrease in PaCO₂ - **Answer:** C) Chronic respiratory acidosis is fully compensated - **Rationale:** Over time, the kidneys compensate by retaining bicarbonate. **Respiratory Alkalosis** 40. **A nurse is assessing a patient with respiratory alkalosis. Which finding is expected?** - A\) Hyperkalemia - B\) Hypocalcemia - C\) Bradypnea - D\) Kussmaul respirations - **Answer:** B) Hypocalcemia - **Rationale:** Alkalosis increases calcium binding to albumin, reducing free calcium levels. 41. **Which lab result supports a diagnosis of respiratory alkalosis?** - A\) pH 7.30, PaCO₂ 50, HCO₃⁻ 22 - B\) pH 7.48, PaCO₂ 30, HCO₃⁻ 22 - C\) pH 7.33, PaCO₂ 35, HCO₃⁻ 18 - D\) pH 7.52, PaCO₂ 40, HCO₃⁻ 30 - **Answer:** B) pH 7.48, PaCO₂ 30, HCO₃⁻ 22 - **Rationale:** High pH and low PaCO₂ indicate respiratory alkalosis. **Metabolic Acidosis** 42. **A patient with renal failure is most likely to develop which imbalance?** - A\) Metabolic acidosis - B\) Metabolic alkalosis - C\) Respiratory acidosis - D\) Respiratory alkalosis - **Answer:** A) Metabolic acidosis - **Rationale:** The kidneys fail to excrete hydrogen ions, leading to acidosis. 43. **Which intervention is most appropriate for a patient with metabolic acidosis due to diabetic ketoacidosis (DKA)?** - A\) Administer sodium bicarbonate immediately - B\) Provide insulin and IV fluids - C\) Encourage hyperventilation - D\) Restrict fluid intake - **Answer:** B) Provide insulin and IV fluids - **Rationale:** Insulin corrects hyperglycemia and stops ketone production. **Metabolic Alkalosis** 44. **A patient receiving loop diuretics is at risk for which acid-base imbalance?** - A\) Respiratory acidosis - B\) Respiratory alkalosis - C\) Metabolic acidosis - D\) Metabolic alkalosis - **Answer:** D) Metabolic alkalosis - **Rationale:** Loop diuretics cause excessive loss of hydrogen and potassium. 45. **What is the priority nursing intervention for metabolic alkalosis?** - A\) Administer sodium bicarbonate - B\) Monitor for tetany and seizures - C\) Encourage hyperventilation - D\) Give potassium-wasting diuretics - **Answer:** B) Monitor for tetany and seizures - **Rationale:** Hypocalcemia and neuromuscular symptoms can occur with alkalosis.