CRNI Fluid and Electrolyte Balance 5

Question 1

A postoperative patient has decreased urine output, pulmonary crackles, and a serum sodium of 148 mEq/L. Which fluid overload pattern does this represent?

Accepted Answer

Hypertonic fluid excess

Answer

Elevated sodium with signs of fluid overload indicates hypertonic hypervolemia, often from excessive saline infusion.

Question 2

Which clinical sign best differentiates third-spacing from true dehydration?

Accepted Answer

Normal or elevated total body water with intravascular deficit

Answer

Third-spacing causes intravascular depletion despite normal or increased total body fluid, unlike true dehydration.

Question 3

A patient with SIADH has a urine osmolality of 600 mOsm/kg and serum osmolality of 260 mOsm/kg. What does this indicate?

Accepted Answer

Inappropriate ADH secretion causing concentrated urine despite dilute serum

Answer

In SIADH, urine is inappropriately concentrated relative to a dilute serum, reflecting unregulated ADH activity.

Question 4

Which fluid is considered the most physiologically balanced crystalloid for large-volume resuscitation?

Accepted Answer

Plasmalyte or Lactated Ringer's

Answer

Balanced crystalloids like Plasmalyte and Lactated Ringer's closely mimic plasma electrolyte composition and reduce hyperchloremic acidosis risk.

Question 5

A patient with Addison's disease presents with weakness, hypotension, and a serum sodium of 128 mEq/L with potassium of 6.0 mEq/L. What is the underlying fluid-electrolyte mechanism?

Accepted Answer

Aldosterone deficiency causing sodium loss and potassium retention

Answer

Aldosterone deficiency in Addison's disease impairs sodium retention and potassium excretion, causing hyponatremia and hyperkalemia.

CRNI Exam Practice Test

CRNI Exam Practice Test

CRNI Fluid and Electrolyte Balance 5