Page 1 of 158
PASS CCRN EXAM THIS YEAR WITH COMPLETE
500 QUESTIONS AND CORRECT SOLUTIONS JUST
RELEASED
QUESTION: 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 - 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.
QUESTION: 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.
, Page 2 of 158
C. The potassium would remain at approximately 5 mEq/L.
D. The potassium would increase to approximately 6 mEq/L. - 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.
QUESTION: 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 - ANSWER✔✔Tetany.
, Page 3 of 158
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.
QUESTION: 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 - 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."
, Page 4 of 158
QUESTION: 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 - 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.
QUESTION: 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?
PASS CCRN EXAM THIS YEAR WITH COMPLETE
500 QUESTIONS AND CORRECT SOLUTIONS JUST
RELEASED
QUESTION: 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 - 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.
QUESTION: 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.
, Page 2 of 158
C. The potassium would remain at approximately 5 mEq/L.
D. The potassium would increase to approximately 6 mEq/L. - 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.
QUESTION: 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 - ANSWER✔✔Tetany.
, Page 3 of 158
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.
QUESTION: 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 - 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."
, Page 4 of 158
QUESTION: 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 - 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.
QUESTION: 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?
