,NSG3850/NSG 3850 Exam 1 | Pathophysiology for
Nurses II | Galen | 26/27 Guaranteed(PDF)
1. A patient with chronic kidney disease develops metabolic acidosis. Which compensatory
mechanism does the body initiate first to restore acid-base balance?
A) Increased renal excretion of bicarbonate
B) Increased respiratory rate to blow off carbon dioxide
C) Decreased respiratory rate to retain carbon dioxide
D) Increased renal reabsorption of hydrogen ions
Correct Answer: Increased respiratory rate to blow off carbon dioxide
Rationale: In metabolic acidosis, the primary compensatory response is respiratory alkalosis through
hyperventilation, which lowers PaCO2. Renal compensation takes hours to days, not minutes.
Increased renal excretion of bicarbonate would worsen acidosis, and decreasing respiratory rate
would retain CO2 and further acidify the blood.
2. A patient's arterial blood gas reveals pH 7.32, PaCO2 48 mmHg, and HCO3- 24 mEq/L. Which
condition does this profile indicate?
A) Metabolic acidosis with full respiratory compensation
B) Respiratory acidosis with no renal compensation
C) Metabolic alkalosis with respiratory compensation
D) Respiratory alkalosis with metabolic compensation
Correct Answer: Respiratory acidosis with no renal compensation
Rationale: The pH is below normal (7.35-7.45), indicating acidosis. The elevated PaCO2 above 45
mmHg indicates a respiratory cause. The HCO3- is within normal range (22-26 mEq/L), showing that
renal compensation has not yet occurred. Metabolic acidosis would show a low HCO3-, and alkalosis
would show an elevated pH.
3. A patient with vomiting from pyloric stenosis loses large amounts of gastric acid. What acid-base
disturbance is most likely to develop?
A) Metabolic acidosis
,B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: Metabolic alkalosis
Rationale: Vomiting of gastric contents causes loss of hydrochloric acid (HCl) from the stomach,
leading to a net gain of bicarbonate in the extracellular fluid. This results in metabolic alkalosis.
Metabolic acidosis is associated with diarrhea or renal failure. Respiratory disturbances involve
changes in PaCO2, not direct loss of acid from the GI tract.
4. Which finding in a patient with diabetic ketoacidosis (DKA) indicates that the kidneys are
attempting to compensate for the acid-base imbalance?
A) Increased respiratory rate
B) Decreased serum potassium level
C) Increased urine pH
D) Increased renal excretion of ammonium
Correct Answer: Increased renal excretion of ammonium
Rationale: In metabolic acidosis, the kidneys compensate by increasing the excretion of hydrogen ions
and generating new bicarbonate. One mechanism is increased ammonium (NH4+) excretion.
Increased respiratory rate is respiratory compensation, not renal. Decreased serum potassium is not a
compensatory mechanism. Urine pH would decrease, not increase.
5. A patient with severe anxiety is breathing rapidly and reports tingling in the fingers and around the
mouth. Which acid-base disturbance is most likely?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: Respiratory alkalosis
, Rationale: Hyperventilation from anxiety causes excessive loss of carbon dioxide, leading to a
decrease in PaCO2 and an increase in pH, resulting in respiratory alkalosis. The tingling sensations are
due to hypocalcemia caused by the alkalotic state. Respiratory acidosis would result from
hypoventilation, and metabolic disturbances involve changes in bicarbonate.
6. A patient with renal failure has a serum potassium level of 6.8 mEq/L. Which electrocardiographic
change is most characteristic of this electrolyte imbalance?
A) Peaked T waves
B) Flattened T waves
C) Prolonged PR interval
D) ST segment depression
Correct Answer: Peaked T waves
Rationale: Hyperkalemia (serum K+ > 5.0 mEq/L) classically presents with tall, peaked, narrow-based T
waves on ECG. Flattened T waves and ST depression are characteristic of hypokalemia. Prolonged PR
interval can occur in both hyperkalemia and hypokalemia but is not the most specific finding for
hyperkalemia.
7. A patient with heart failure is receiving furosemide and develops muscle weakness, lethargy, and a
serum potassium of 2.9 mEq/L. Which pathophysiological mechanism explains the muscle weakness?
A) Hyperpolarization of skeletal muscle cell membranes
B) Depolarization block due to sodium channel inactivation
C) Decreased calcium release from the sarcoplasmic reticulum
D) Increased acetylcholine breakdown at the neuromuscular junction
Correct Answer: Hyperpolarization of skeletal muscle cell membranes
Rationale: Hypokalemia increases the resting membrane potential (makes it more negative), causing
hyperpolarization. This makes the muscle cell less excitable and more resistant to depolarization,
leading to muscle weakness. Depolarization block is associated with hyperkalemia. Calcium release
and acetylcholine breakdown are not directly affected by potassium levels.
8. A patient with syndrome of inappropriate antidiuretic hormone (SIADH) has a serum sodium of 118
mEq/L. Which assessment finding is most directly related to this electrolyte disturbance?
Nurses II | Galen | 26/27 Guaranteed(PDF)
1. A patient with chronic kidney disease develops metabolic acidosis. Which compensatory
mechanism does the body initiate first to restore acid-base balance?
A) Increased renal excretion of bicarbonate
B) Increased respiratory rate to blow off carbon dioxide
C) Decreased respiratory rate to retain carbon dioxide
D) Increased renal reabsorption of hydrogen ions
Correct Answer: Increased respiratory rate to blow off carbon dioxide
Rationale: In metabolic acidosis, the primary compensatory response is respiratory alkalosis through
hyperventilation, which lowers PaCO2. Renal compensation takes hours to days, not minutes.
Increased renal excretion of bicarbonate would worsen acidosis, and decreasing respiratory rate
would retain CO2 and further acidify the blood.
2. A patient's arterial blood gas reveals pH 7.32, PaCO2 48 mmHg, and HCO3- 24 mEq/L. Which
condition does this profile indicate?
A) Metabolic acidosis with full respiratory compensation
B) Respiratory acidosis with no renal compensation
C) Metabolic alkalosis with respiratory compensation
D) Respiratory alkalosis with metabolic compensation
Correct Answer: Respiratory acidosis with no renal compensation
Rationale: The pH is below normal (7.35-7.45), indicating acidosis. The elevated PaCO2 above 45
mmHg indicates a respiratory cause. The HCO3- is within normal range (22-26 mEq/L), showing that
renal compensation has not yet occurred. Metabolic acidosis would show a low HCO3-, and alkalosis
would show an elevated pH.
3. A patient with vomiting from pyloric stenosis loses large amounts of gastric acid. What acid-base
disturbance is most likely to develop?
A) Metabolic acidosis
,B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: Metabolic alkalosis
Rationale: Vomiting of gastric contents causes loss of hydrochloric acid (HCl) from the stomach,
leading to a net gain of bicarbonate in the extracellular fluid. This results in metabolic alkalosis.
Metabolic acidosis is associated with diarrhea or renal failure. Respiratory disturbances involve
changes in PaCO2, not direct loss of acid from the GI tract.
4. Which finding in a patient with diabetic ketoacidosis (DKA) indicates that the kidneys are
attempting to compensate for the acid-base imbalance?
A) Increased respiratory rate
B) Decreased serum potassium level
C) Increased urine pH
D) Increased renal excretion of ammonium
Correct Answer: Increased renal excretion of ammonium
Rationale: In metabolic acidosis, the kidneys compensate by increasing the excretion of hydrogen ions
and generating new bicarbonate. One mechanism is increased ammonium (NH4+) excretion.
Increased respiratory rate is respiratory compensation, not renal. Decreased serum potassium is not a
compensatory mechanism. Urine pH would decrease, not increase.
5. A patient with severe anxiety is breathing rapidly and reports tingling in the fingers and around the
mouth. Which acid-base disturbance is most likely?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
Correct Answer: Respiratory alkalosis
, Rationale: Hyperventilation from anxiety causes excessive loss of carbon dioxide, leading to a
decrease in PaCO2 and an increase in pH, resulting in respiratory alkalosis. The tingling sensations are
due to hypocalcemia caused by the alkalotic state. Respiratory acidosis would result from
hypoventilation, and metabolic disturbances involve changes in bicarbonate.
6. A patient with renal failure has a serum potassium level of 6.8 mEq/L. Which electrocardiographic
change is most characteristic of this electrolyte imbalance?
A) Peaked T waves
B) Flattened T waves
C) Prolonged PR interval
D) ST segment depression
Correct Answer: Peaked T waves
Rationale: Hyperkalemia (serum K+ > 5.0 mEq/L) classically presents with tall, peaked, narrow-based T
waves on ECG. Flattened T waves and ST depression are characteristic of hypokalemia. Prolonged PR
interval can occur in both hyperkalemia and hypokalemia but is not the most specific finding for
hyperkalemia.
7. A patient with heart failure is receiving furosemide and develops muscle weakness, lethargy, and a
serum potassium of 2.9 mEq/L. Which pathophysiological mechanism explains the muscle weakness?
A) Hyperpolarization of skeletal muscle cell membranes
B) Depolarization block due to sodium channel inactivation
C) Decreased calcium release from the sarcoplasmic reticulum
D) Increased acetylcholine breakdown at the neuromuscular junction
Correct Answer: Hyperpolarization of skeletal muscle cell membranes
Rationale: Hypokalemia increases the resting membrane potential (makes it more negative), causing
hyperpolarization. This makes the muscle cell less excitable and more resistant to depolarization,
leading to muscle weakness. Depolarization block is associated with hyperkalemia. Calcium release
and acetylcholine breakdown are not directly affected by potassium levels.
8. A patient with syndrome of inappropriate antidiuretic hormone (SIADH) has a serum sodium of 118
mEq/L. Which assessment finding is most directly related to this electrolyte disturbance?
