PASS CCRN Questions with Detailed Verified
Answers
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 Ans: 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 Ans: 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 Ans: 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. Ans: 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
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, 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 Ans: 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
© Get it right 2025 Getaway - Stuvia US All rights reserved
Answers
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 Ans: 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 Ans: 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 Ans: 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. Ans: 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
© Get it right 2025 Getaway - Stuvia US All rights reserved
, 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 Ans: 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
© Get it right 2025 Getaway - Stuvia US All rights reserved
