PASS CCRN TEST EXAM QUESTIONS AND ANSWERS
(VERIFIED AND WELL DETAILED ANSWERS) LATEST
UPDATE 2025/2026
The electrolyte imbalance that is a frequent cause of postoperative paralytic ileus is which of the
following?
A. Hypocalcemia
B. Hypokalemia
C. Hypomagnesemia
D. Hyponatremia - CORRECT ANSWER Hypokalemia decreases gastric motility and often
occurs after surgery, primarily because of the action of aldosterone. Nasogastric suctioning,
vomiting, and diuresis also may contribute to perioperative potassium loss.
A patient receiving an angiotensin-converting enzyme (ACE) inhibitor and spironolactone for
heart failure is at risk for which electrolyte imbalance?
A. Hypernatremia
B. Hyperkalemia
C. Hypocalcemia
D. Hypophosphatemia - CORRECT ANSWER Hyperkalemia. Because ACE inhibitors block
the release of aldosterone, and spironolactone is an aldosterone antagonist, the action of
aldosterone is diminished. Because aldosterone causes the retention of sodium and water and the
excretion of potassium, the patient is at risk for hyperkalemia.
Remember that spironolactone traditionally has been called a potassium-sparing diuretic. Thus it
would cause the retention of potassium.
A patient with an electrical burn develops brown urine. The urinalysis confirms myoglobinuria.
Which of the following interventions would you anticipate to prevent the development of acute
tubular necrosis and kidney injury in this patient?
A. Saline, mannitol, and bicarbonate
B. Colloids, furosemide, and dopamine
,C. Blood, furosemide, and dobutamine
D. Lactated Ringer solution, hydrochlorothiazide, and dopamine - CORRECT ANSWER
Saline, mannitol, and bicarbonate. The destruction of muscle by the electricity has caused
myoglobin to appear in the urine. Myoglobin is a heavy pigment that can cause acute tubular
necrosis and kidney injury. The treatment for myoglobinuria is to flush the pigments through
with fluids, usually saline, and diuretics, usually mannitol. Alkalinization of the urine using
sodium bicarbonate intravenously also may be prescribed to increase the excretion of the
myoglobin.
A patient with diabetic ketoacidosis was admitted to the critical care unit from the emergency
department. His initial laboratory results included serum glucose 660 mg/dl, pH 7.0, and serum
potassium of 5 mEq/L. As the pH is corrected with insulin and fluids, what would be the
anticipated change in his potassium?
A. The potassium would decrease to approximately 3 mEq/L.
B. The potassium would decrease to approximately 4 mEq/L.
C. The potassium would remain at approximately 5 mEq/L.
D. The potassium would increase to approximately 6 mEq/L. - CORRECT ANSWER The
potassium would decrease to approximately 3 mEq/L.
Changes in pH causes potassium to move either into or out of the cell. Acidosis causes potassium
to leave the cell and increases serum potassium levels, whereas alkalosis causes potassium to
enter the cell and decreases serum potassium. For every change in pH of 0.1, the potassium
moves 0.5 mEq/L in the opposite direction. In this patient the pH has changed 4 × 0.1 from the
midline normal pH of 7.4 so the serum potassium is expected to decrease by 2 mEq/L (0.5 × 4)
when the pH is corrected. So 5 minus 2 mEq/L is 3 mEq/L and this is what the potassium would
be expected to fall to with correction of the pH. Potassium replacement is indicated now even
though his potassium is currently at a high normal level. The potassium level will plummet as
insulin and fluids correct the blood glucose and pH.
If you remember there is a change in serum potassium level with pH changes, you eliminate 5
mEq/L. Also, remember the change in pH and the change in serum potassium is inverse, do you
eliminate 6 mEq/L. To choose between 3 mEq/L and 4 mEq/L, you need to know how significant
a change is expected.
Magnesium is being administered to a patient admitted with acute myocardial infarction. Which
of the following would not be an indication that magnesium levels are too high?
A. Diminished deep tendon reflexes
B. Hypotension
,C. Tetany
D. Muscle weakness - CORRECT ANSWER Tetany.
High levels of magnesium cause smooth muscle relaxation, resulting in hypotension, diminished
deep tendon reflexes, and muscle weakness, potentially resulting in respiratory muscle paralysis
and respiratory arrest. Tetany occurs with hypomagnesemia.
Notice that "Diminished deep tendon reflexes, Hypotension," and "Muscle weakness" indicate a
relaxant effect or weakness. Option "Tetany" is an increase in irritability. Choose "Tetany"
because the question asks what would not be an indication of high magnesium.
A 77-year-old woman reports explosive diarrhea for 48 hours. She is extremely lethargic.
Mucous membranes are dry and sticky, and the urine is dark amber with a specific gravity of
1.035. Vital signs are temperature 38.2° C orally; heart rate 130 beats/min and regular;
respiratory rate 26 breaths/min and regular; and blood pressure 90/74 mm Hg. Which of the
following is of the most immediate concern?
A. Infection
B. Hypovolemia
C. Nutrition
D. Skin breakdown - CORRECT ANSWER Correction of hypovolemia is of immediate
concern. Sympathetic nervous system stimulation is evidenced by the narrowed pulse pressure
and tachycardia. Volume depletion is evidenced by the temperature elevation; dry, sticky mucous
membranes; and small volumes of dark, concentrated urine. Because the major function of the
large intestine is to absorb approximately 8 L of water per day, fluid loss is critical in ongoing
diarrhea. If not corrected, it may lead to hypovolemic shock and death.
If you have no idea of the correct answer, consider which option is potentially life threatening.
Hypovolemia, especially in an older adult, is the most life threatening of the options given.
Choose "Hypovolemia."
A 29-year-old woman has been a patient in the critical care unit for 2 weeks with acute tubular
necrosis (ATN) as a result of crush injuries experienced in a motor vehicle collision. She was
normotensive on admission. What would be the most common explanation for her ATN?
A. Rhabdomyolysis
B. Hemorrhage
C. Creatinine release
, D. Cardiac dysrhythmias - CORRECT ANSWER The most common cause for ATN in a
normotensive patient who has experienced crush injuries is rhabdomyolysis with resultant
myoglobinuria. Rhabdomyolysis is acute muscle destruction and is associated with
myoglobinuria. Myoglobin released from muscle cells may cause acute kidney injury by having
a direct toxic effect on tubule epithelial cells or inducing intratubular cast formation.
The key points in this question are that she had a crush injury and that she was not hypotensive.
Hemorrhage or dysrhythmias significant enough to cause ATN certainly would cause
hypotension, so eliminate "Hemorrhage and Cardiac Dysfunction." Creatinine is a normal waste
product that normal kidneys easily excrete, so eliminate option "Creatinine release."
Rhabdomyolysis causes myoglobin release, which is toxic to the renal tubules, especially in large
amounts as would occur in a crush injury. Choose the "Rhabdomyolysis" option.
A 30-year-old man was electrocuted with 440 volts of electrical current. An entry wound was
noted in his left hand, and a large exit wound was noted on the sole of his right foot. Eight hours
after admission into the critical care unit, the nurse observes that the urine is brownish. A
specimen is sent to the laboratory. What intervention is anticipated?
A. Rapid fluid administration and dopamine at 2 mcg/kg/min
B. Furosemide (Lasix) 10 mg IV and dopamine at 2 mcg/kg/min
C. Rapid fluid administration and 25 g of 20% mannitol
D. Insertion of a double-lumen vascular catheter and hemodialysis - CORRECT ANSWER
Myoglobin is muscle protein that is seen in the urine after extensive muscle injury such as
electrical burns, status epilepticus, and crush injuries. Myoglobin may cause acute tubular
necrosis. To prevent damage to the tubules, forced diuresis with fluids and osmotic diuretics
usually is initiated. Alkalinization of the urine through intravenous administration of sodium
bicarbonate also may be initiated.
The single most important intervention when any renal toxin (e.g., nephrotoxic antibiotics,
nephrotoxic dyes, and myoglobin) is present is to flush the toxins through the renal tubules with
lots of fluids. Because "Rapid fluid administration and dopamine at 2 mcg/kg/min" and "Rapid
fluid administration and 25 g of 20% mannitol" options include rapid fluid administration,
narrow your choices to these options. Next, consider all that fluid may be a problem and a
diuretic is likely appropriate to help eliminate the excess fluid. Also, low-dose dopamine no
longer is recommended to increase renal flow.
A patient admitted with Goodpasture syndrome has developed acute tubular necrosis. The
patient's phosphorus level is 6.5 mg/dl. Control of the phosphorus is important to avoid
complications from which of the following?
A. Hyponatremia
(VERIFIED AND WELL DETAILED ANSWERS) LATEST
UPDATE 2025/2026
The electrolyte imbalance that is a frequent cause of postoperative paralytic ileus is which of the
following?
A. Hypocalcemia
B. Hypokalemia
C. Hypomagnesemia
D. Hyponatremia - CORRECT ANSWER Hypokalemia decreases gastric motility and often
occurs after surgery, primarily because of the action of aldosterone. Nasogastric suctioning,
vomiting, and diuresis also may contribute to perioperative potassium loss.
A patient receiving an angiotensin-converting enzyme (ACE) inhibitor and spironolactone for
heart failure is at risk for which electrolyte imbalance?
A. Hypernatremia
B. Hyperkalemia
C. Hypocalcemia
D. Hypophosphatemia - CORRECT ANSWER Hyperkalemia. Because ACE inhibitors block
the release of aldosterone, and spironolactone is an aldosterone antagonist, the action of
aldosterone is diminished. Because aldosterone causes the retention of sodium and water and the
excretion of potassium, the patient is at risk for hyperkalemia.
Remember that spironolactone traditionally has been called a potassium-sparing diuretic. Thus it
would cause the retention of potassium.
A patient with an electrical burn develops brown urine. The urinalysis confirms myoglobinuria.
Which of the following interventions would you anticipate to prevent the development of acute
tubular necrosis and kidney injury in this patient?
A. Saline, mannitol, and bicarbonate
B. Colloids, furosemide, and dopamine
,C. Blood, furosemide, and dobutamine
D. Lactated Ringer solution, hydrochlorothiazide, and dopamine - CORRECT ANSWER
Saline, mannitol, and bicarbonate. The destruction of muscle by the electricity has caused
myoglobin to appear in the urine. Myoglobin is a heavy pigment that can cause acute tubular
necrosis and kidney injury. The treatment for myoglobinuria is to flush the pigments through
with fluids, usually saline, and diuretics, usually mannitol. Alkalinization of the urine using
sodium bicarbonate intravenously also may be prescribed to increase the excretion of the
myoglobin.
A patient with diabetic ketoacidosis was admitted to the critical care unit from the emergency
department. His initial laboratory results included serum glucose 660 mg/dl, pH 7.0, and serum
potassium of 5 mEq/L. As the pH is corrected with insulin and fluids, what would be the
anticipated change in his potassium?
A. The potassium would decrease to approximately 3 mEq/L.
B. The potassium would decrease to approximately 4 mEq/L.
C. The potassium would remain at approximately 5 mEq/L.
D. The potassium would increase to approximately 6 mEq/L. - CORRECT ANSWER The
potassium would decrease to approximately 3 mEq/L.
Changes in pH causes potassium to move either into or out of the cell. Acidosis causes potassium
to leave the cell and increases serum potassium levels, whereas alkalosis causes potassium to
enter the cell and decreases serum potassium. For every change in pH of 0.1, the potassium
moves 0.5 mEq/L in the opposite direction. In this patient the pH has changed 4 × 0.1 from the
midline normal pH of 7.4 so the serum potassium is expected to decrease by 2 mEq/L (0.5 × 4)
when the pH is corrected. So 5 minus 2 mEq/L is 3 mEq/L and this is what the potassium would
be expected to fall to with correction of the pH. Potassium replacement is indicated now even
though his potassium is currently at a high normal level. The potassium level will plummet as
insulin and fluids correct the blood glucose and pH.
If you remember there is a change in serum potassium level with pH changes, you eliminate 5
mEq/L. Also, remember the change in pH and the change in serum potassium is inverse, do you
eliminate 6 mEq/L. To choose between 3 mEq/L and 4 mEq/L, you need to know how significant
a change is expected.
Magnesium is being administered to a patient admitted with acute myocardial infarction. Which
of the following would not be an indication that magnesium levels are too high?
A. Diminished deep tendon reflexes
B. Hypotension
,C. Tetany
D. Muscle weakness - CORRECT ANSWER Tetany.
High levels of magnesium cause smooth muscle relaxation, resulting in hypotension, diminished
deep tendon reflexes, and muscle weakness, potentially resulting in respiratory muscle paralysis
and respiratory arrest. Tetany occurs with hypomagnesemia.
Notice that "Diminished deep tendon reflexes, Hypotension," and "Muscle weakness" indicate a
relaxant effect or weakness. Option "Tetany" is an increase in irritability. Choose "Tetany"
because the question asks what would not be an indication of high magnesium.
A 77-year-old woman reports explosive diarrhea for 48 hours. She is extremely lethargic.
Mucous membranes are dry and sticky, and the urine is dark amber with a specific gravity of
1.035. Vital signs are temperature 38.2° C orally; heart rate 130 beats/min and regular;
respiratory rate 26 breaths/min and regular; and blood pressure 90/74 mm Hg. Which of the
following is of the most immediate concern?
A. Infection
B. Hypovolemia
C. Nutrition
D. Skin breakdown - CORRECT ANSWER Correction of hypovolemia is of immediate
concern. Sympathetic nervous system stimulation is evidenced by the narrowed pulse pressure
and tachycardia. Volume depletion is evidenced by the temperature elevation; dry, sticky mucous
membranes; and small volumes of dark, concentrated urine. Because the major function of the
large intestine is to absorb approximately 8 L of water per day, fluid loss is critical in ongoing
diarrhea. If not corrected, it may lead to hypovolemic shock and death.
If you have no idea of the correct answer, consider which option is potentially life threatening.
Hypovolemia, especially in an older adult, is the most life threatening of the options given.
Choose "Hypovolemia."
A 29-year-old woman has been a patient in the critical care unit for 2 weeks with acute tubular
necrosis (ATN) as a result of crush injuries experienced in a motor vehicle collision. She was
normotensive on admission. What would be the most common explanation for her ATN?
A. Rhabdomyolysis
B. Hemorrhage
C. Creatinine release
, D. Cardiac dysrhythmias - CORRECT ANSWER The most common cause for ATN in a
normotensive patient who has experienced crush injuries is rhabdomyolysis with resultant
myoglobinuria. Rhabdomyolysis is acute muscle destruction and is associated with
myoglobinuria. Myoglobin released from muscle cells may cause acute kidney injury by having
a direct toxic effect on tubule epithelial cells or inducing intratubular cast formation.
The key points in this question are that she had a crush injury and that she was not hypotensive.
Hemorrhage or dysrhythmias significant enough to cause ATN certainly would cause
hypotension, so eliminate "Hemorrhage and Cardiac Dysfunction." Creatinine is a normal waste
product that normal kidneys easily excrete, so eliminate option "Creatinine release."
Rhabdomyolysis causes myoglobin release, which is toxic to the renal tubules, especially in large
amounts as would occur in a crush injury. Choose the "Rhabdomyolysis" option.
A 30-year-old man was electrocuted with 440 volts of electrical current. An entry wound was
noted in his left hand, and a large exit wound was noted on the sole of his right foot. Eight hours
after admission into the critical care unit, the nurse observes that the urine is brownish. A
specimen is sent to the laboratory. What intervention is anticipated?
A. Rapid fluid administration and dopamine at 2 mcg/kg/min
B. Furosemide (Lasix) 10 mg IV and dopamine at 2 mcg/kg/min
C. Rapid fluid administration and 25 g of 20% mannitol
D. Insertion of a double-lumen vascular catheter and hemodialysis - CORRECT ANSWER
Myoglobin is muscle protein that is seen in the urine after extensive muscle injury such as
electrical burns, status epilepticus, and crush injuries. Myoglobin may cause acute tubular
necrosis. To prevent damage to the tubules, forced diuresis with fluids and osmotic diuretics
usually is initiated. Alkalinization of the urine through intravenous administration of sodium
bicarbonate also may be initiated.
The single most important intervention when any renal toxin (e.g., nephrotoxic antibiotics,
nephrotoxic dyes, and myoglobin) is present is to flush the toxins through the renal tubules with
lots of fluids. Because "Rapid fluid administration and dopamine at 2 mcg/kg/min" and "Rapid
fluid administration and 25 g of 20% mannitol" options include rapid fluid administration,
narrow your choices to these options. Next, consider all that fluid may be a problem and a
diuretic is likely appropriate to help eliminate the excess fluid. Also, low-dose dopamine no
longer is recommended to increase renal flow.
A patient admitted with Goodpasture syndrome has developed acute tubular necrosis. The
patient's phosphorus level is 6.5 mg/dl. Control of the phosphorus is important to avoid
complications from which of the following?
A. Hyponatremia
