MSNCB Fluid & Electrolyte Balance 3

Question 1

A patient develops confusion, muscle twitching, and seizures after receiving multiple blood transfusions. Which electrolyte imbalance is most likely responsible?

Accepted Answer

Hypocalcemia

Answer

Citrate preservatives in stored blood bind free calcium, causing hypocalcemia, which manifests as confusion, muscle twitching, and seizures during massive transfusions.

Question 2

Which set of findings would most clearly differentiate diabetes insipidus (DI) from SIADH?

Accepted Answer

Elevated serum sodium and dilute urine in DI

Answer

Diabetes insipidus results from deficient ADH, causing massive dilute urine output, dehydration, and hypernatremia — the opposite of SIADH's profile.

Question 3

A post-operative patient who underwent bowel resection develops third-spacing with hypotension and decreased urine output. Which IV fluid replacement is most appropriate?

Accepted Answer

Isotonic crystalloid such as 0.9% NaCl or lactated Ringer's

Answer

Third-spacing shifts fluid into non-functional spaces, depleting intravascular volume; isotonic crystalloids are first-line to restore functional circulating blood volume.

Question 4

A patient with chronic kidney disease has a serum potassium of 5.8 mEq/L. Which dietary instruction is the most important priority?

Accepted Answer

Avoid high-potassium foods such as bananas, oranges, and potatoes

Answer

CKD impairs renal potassium excretion; restricting high-potassium foods is essential to prevent hyperkalemia from rising to levels that cause fatal cardiac arrhythmias.

Question 5

Which arterial blood gas result indicates respiratory alkalosis?

Accepted Answer

pH 7.50, PaCO2 28, HCO3 22

Answer

Respiratory alkalosis is characterized by an elevated pH (>7.45) and decreased PaCO2 (<35 mmHg) from hyperventilation, with near-normal bicarbonate if uncompensated.

(MSNCB) Medical-Surgical Nursing Certification Board Practice Test

(MSNCB) Medical-Surgical Nursing Certification Board Practice Test

MSNCB Fluid & Electrolyte Balance 3