FCCS FCCS Fluid and Electrolyte Management 2

Question 1

A patient with hyperkalemia (K+ = 6.8 mEq/L) shows peaked T-waves and widened QRS on ECG. What is the FIRST intervention?

Accepted Answer

Calcium gluconate IV

Answer

Calcium gluconate stabilizes the cardiac membrane and counteracts the cardiotoxic effects of hyperkalemia; it should be given first when ECG changes are present.

Question 2

A critically ill patient develops carpopedal spasm and a positive Chvostek's sign. Which electrolyte abnormality is most likely?

Accepted Answer

Hypocalcemia

Answer

Hypocalcemia causes neuromuscular excitability, manifesting as carpopedal spasm, Chvostek's sign (facial nerve tapping), and Trousseau's sign.

Question 3

Which electrolyte deficiency must be corrected before refractory hypokalemia can be successfully treated?

Accepted Answer

Magnesium

Answer

Hypomagnesemia impairs renal potassium conservation and cellular potassium uptake, making hypokalemia refractory to replacement until magnesium is corrected.

Question 4

What is the maximum recommended rate of sodium correction in chronic hyponatremia to prevent osmotic demyelination syndrome?

Accepted Answer

8–10 mEq/L per 24 hours

Answer

Correcting chronic hyponatremia faster than 8–10 mEq/L per 24 hours risks osmotic demyelination (central pontine myelinolysis), a devastating neurological complication.

Question 5

In diabetic ketoacidosis (DKA), why may serum potassium appear normal or elevated despite total body potassium depletion?

Accepted Answer

Acidosis shifts potassium from intracellular to extracellular fluid

Answer

Metabolic acidosis drives hydrogen ions into cells in exchange for potassium moving out, falsely elevating serum potassium despite total body depletion.

FCCS - Fundamentals of Critical Care Support Practice Test

FCCS - Fundamentals of Critical Care Support Practice Test

FCCS FCCS Fluid and Electrolyte Management 2