Fluid and Electrolyte Balance Flashcards
7 cards from real CRNI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Fluid and Electrolyte Balance flashcards as text
A postoperative patient has decreased urine output, pulmonary crackles, and a serum sodium of 148 mEq/L. Which fluid overload pattern does this represent?
Answer: Hypertonic fluid excess
Elevated sodium with signs of fluid overload indicates hypertonic hypervolemia, often from excessive saline infusion.
Which clinical sign best differentiates third-spacing from true dehydration?
Answer: Normal or elevated total body water with intravascular deficit
Third-spacing causes intravascular depletion despite normal or increased total body fluid, unlike true dehydration.
A patient with SIADH has a urine osmolality of 600 mOsm/kg and serum osmolality of 260 mOsm/kg. What does this indicate?
Answer: Inappropriate ADH secretion causing concentrated urine despite dilute serum
In SIADH, urine is inappropriately concentrated relative to a dilute serum, reflecting unregulated ADH activity.
Which fluid is considered the most physiologically balanced crystalloid for large-volume resuscitation?
Answer: Plasmalyte or Lactated Ringer's
Balanced crystalloids like Plasmalyte and Lactated Ringer's closely mimic plasma electrolyte composition and reduce hyperchloremic acidosis risk.
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?
Answer: Aldosterone deficiency causing sodium loss and potassium retention
Aldosterone deficiency in Addison's disease impairs sodium retention and potassium excretion, causing hyponatremia and hyperkalemia.
A patient receiving 0.9% NaCl at 200 mL/hr for 12 hours develops a pH of 7.28, HCO3 of 18, and Cl of 116. What has occurred?
Answer: Hyperchloremic metabolic acidosis
Large volumes of normal saline cause dilutional hyperchloremic (non-anion gap) metabolic acidosis by lowering bicarbonate relative to chloride.
Which assessment parameter is MOST useful for evaluating fluid status in a patient with severe hypoalbuminemia?
Answer: Daily weight measurement
Daily weight is the most reliable indicator of fluid balance, as hypoalbuminemia causes edema that masks clinical signs of dehydration.