DrillRNDownload

Physiological Adaptation

NCLEX Fluid and Electrolyte Practice Questions

Quick answer

Fluid and electrolyte questions test whether you can match a lab value to the signs at the bedside and act on it. They sit inside Physiological Adaptation (11 to 17 percent of the exam) and also show up in Reduction of Risk Potential, so expect several of them on your test.

  • 10 practice questions
  • Full rationales
  • Free

Most students memorize the normal ranges and stop there. The exam does not ask you what a normal potassium is. It gives you a client with a potassium of 6.4 mEq/L, a tall T wave on the monitor, and four things you could do, and it wants the one you do first. The trap on this topic is reading the lab value and jumping to the drug fix before you have checked the client. A peaked T wave, a weak pulse, or a positive Chvostek sign tells you more about urgency than the number alone. Work through these 10 questions with that habit in mind: value, sign, then action.

Practice questions

1

A client receiving dialysis has a serum potassium of 6.8 mEq/L. The nurse notes tall, peaked T waves and a widened QRS on the cardiac monitor. Which action should the nurse take first?

  1. AAdminister the scheduled oral sodium polystyrene sulfonate
  2. BPrepare to give IV calcium gluconate as prescribed
  3. CPlace the client on a low potassium diet
  4. DEncourage the client to ambulate in the hallway
Show answer

Answer: B

Peaked T waves and a widening QRS mean the heart muscle is already irritable, and the next step can be ventricular fibrillation or asystole. IV calcium gluconate does not lower potassium, but it stabilizes the cardiac membrane within minutes and buys time for insulin with dextrose or dialysis to move potassium out of the blood.

Why the others are wrong

Sodium polystyrene sulfonate works over hours through the gut and will not protect the heart right now. A low potassium diet matters for prevention, not for an acute rhythm change. Ambulation adds cardiac workload to a client who could arrest.

2

A client has been taking furosemide for two weeks and reports leg cramps. The nurse should recognize which group of findings as consistent with hypokalemia?

  1. AMuscle weakness, decreased bowel sounds, flattened T waves and a U wave
  2. BDiarrhea, hyperactive bowel sounds, tall peaked T waves
  3. CMuscle twitching, hyperreflexia, positive Trousseau sign
  4. DFlushed skin, thirst, dry sticky mucous membranes
Show answer

Answer: A

Low potassium slows muscle and nerve activity, so the client gets weakness, cramps, a sluggish gut with reduced bowel sounds, and on the ECG a flattened T wave with a U wave after it. Loop diuretics are the most common cause of hypokalemia in a test question.

Why the others are wrong

Diarrhea, hyperactive bowel sounds and peaked T waves describe hyperkalemia. Twitching, hyperreflexia and a positive Trousseau sign point to low calcium or low magnesium. Flushed skin, thirst and dry sticky membranes are classic hypernatremia.

3

A client with small cell lung cancer is admitted with a serum sodium of 121 mEq/L, concentrated urine, and no edema. The provider diagnoses syndrome of inappropriate antidiuretic hormone (SIADH). Which intervention should the nurse expect to implement?

  1. AEncourage oral fluids to at least 3 L per day
  2. BRestrict fluids to 800 to 1,000 mL per day
  3. CAdminister a rapid 1 L bolus of 0.9 percent sodium chloride
  4. DGive a stool softener and a high fiber diet
Show answer

Answer: B

In SIADH the body holds on to water, which dilutes the sodium. The core treatment is fluid restriction, usually around 800 to 1,000 mL a day, along with seizure precautions and neuro checks, because sodium this low can cause confusion and seizures.

Why the others are wrong

Pushing fluids drives the sodium even lower. A rapid saline bolus adds volume the client is already retaining, and sodium must be corrected slowly to avoid osmotic demyelination. A stool softener does nothing for the sodium problem.

4

A client with hypernatremia (serum sodium 158 mEq/L) is receiving IV fluids to correct the level. The nurse should monitor the client most closely for which complication of treatment?

  1. ACerebral edema from correcting the sodium too quickly
  2. BHypertension from the volume of fluid given
  3. CMuscle cramps from falling calcium
  4. DHyperkalemia from the IV solution
Show answer

Answer: A

When sodium has been high, brain cells have adapted by building up solutes. If the serum sodium drops fast, water rushes into those cells and the brain swells. Sodium is lowered slowly, no more than about 8 to 10 mEq/L in 24 hours, with frequent neuro checks for headache, confusion or a drop in level of consciousness.

Why the others are wrong

Hypertension from fluid is possible but is not the specific danger of sodium correction. Calcium does not fall as a direct result of correcting sodium. Hypotonic fluids used for hypernatremia do not carry a potassium load.

5

A client is 8 hours post thyroidectomy. The nurse taps the facial nerve in front of the ear and the client's upper lip and cheek twitch. Which action should the nurse take?

  1. ADocument the finding as a normal postoperative response
  2. BApply a warm compress to the surgical site
  3. CReport the finding and prepare to give IV calcium gluconate
  4. DAssist the client to turn, cough and deep breathe
Show answer

Answer: C

Facial twitching when the nerve is tapped is a positive Chvostek sign, an early warning of hypocalcemia. After thyroidectomy the parathyroid glands may have been bruised or removed, so calcium can drop within the first 24 to 72 hours. The nurse reports it and expects IV calcium gluconate to be ordered, and should also watch for tingling around the mouth, a positive Trousseau sign, and laryngospasm.

Why the others are wrong

It is not a normal finding and should never simply be charted. A warm compress treats nothing here. Turning, coughing and deep breathing are routine post-op care and ignore the emerging problem.

6

A client with multiple myeloma has a serum calcium of 13.2 mg/dL. Which assessment finding would the nurse expect?

  1. ANumbness and tingling of the fingers and around the mouth
  2. BLethargy, constipation and increased thirst
  3. CCarpal spasm when a blood pressure cuff is inflated
  4. DHyperactive deep tendon reflexes
Show answer

Answer: B

High calcium slows nerve and muscle activity, so the client becomes drowsy and confused, the gut slows down causing constipation, and the kidneys lose water, bringing thirst and polyuria. Bone cancer and hyperparathyroidism are the usual causes in exam questions, and the nurse should push fluids as prescribed and watch for kidney stones and dysrhythmias.

Why the others are wrong

Tingling of the fingers and mouth, carpal spasm with a cuff (Trousseau sign) and hyperactive reflexes are all signs of low calcium, not high.

7

A client with a long history of alcohol use disorder is admitted with a serum magnesium of 1.1 mg/dL. Which finding should the nurse report to the provider immediately?

  1. ASerum potassium of 4.0 mEq/L
  2. BBlood pressure of 128/80 mm Hg
  3. CIrregular pulse with a prolonged QT interval on the ECG
  4. DMild tremor of both hands
Show answer

Answer: C

Low magnesium makes the heart electrically unstable. A prolonged QT interval with an irregular rhythm can progress to torsades de pointes, a form of ventricular tachycardia that can kill the client. IV magnesium sulfate is the treatment, and the nurse monitors reflexes and respirations while it runs.

Why the others are wrong

A potassium of 4.0 mEq/L and a blood pressure of 128/80 mm Hg are both normal. Tremor is expected with hypomagnesemia and is worth charting, but it is not the finding that threatens life.

8

The nurse is assessing two clients. Client A has dry mucous membranes, a heart rate of 112 beats per minute, blood pressure of 92/58 mm Hg, and urine output of 20 mL per hour. Client B has crackles in both lung bases, 2+ pitting edema of the ankles, and a bounding pulse. Which conclusion by the nurse is correct?

  1. AClient A has fluid volume excess and Client B has fluid volume deficit
  2. BClient A has fluid volume deficit and Client B has fluid volume excess
  3. CBoth clients have fluid volume deficit
  4. DBoth clients have fluid volume excess
Show answer

Answer: B

Deficit shows up as a fast heart rate, low blood pressure, dry membranes, poor skin turgor, concentrated low urine output, and a rising hematocrit and BUN. Excess shows up as crackles, edema, a bounding pulse, distended neck veins, weight gain and a diluted hematocrit. Client A matches deficit and Client B matches excess.

Why the others are wrong

Option A reverses the two. Options C and D assign the same problem to both clients when their findings point in opposite directions.

9

An 82 year old client who lives alone is brought to the clinic by a family member who says the client has been "confused since yesterday." The client has dry, furrowed tongue, a temperature of 100.2 F, and reports drinking "very little" during a recent heat wave. Which statement by the nurse to the family member shows the best understanding of dehydration in older adults?

  1. A"Confusion is the first sign we look for, since older adults rarely lose skin turgor."
  2. B"We check skin turgor on the back of the hand because it is the most reliable sign at this age."
  3. C"Thirst will tell her when to drink, so we just need to make water available."
  4. D"Her kidneys will hold on to water, so dehydration is less likely at her age."
Show answer

Answer: A

In older adults the thirst reflex is blunted, the kidneys concentrate urine less well, and total body water is lower, so dehydration develops faster and often shows first as a change in mental status. Skin turgor on the hand is unreliable because skin loses elasticity with age; the sternum or forehead is a better site, and a dry furrowed tongue is a stronger clue.

Why the others are wrong

Hand turgor is one of the least reliable signs in an older adult. Thirst cannot be trusted because the reflex fades with age. Aging kidneys are worse at conserving water, not better.

10

A client with type 1 diabetes is admitted with nausea, deep rapid respirations and a fruity breath odor. Arterial blood gas results are pH 7.24, PaCO2 28 mm Hg, HCO3 14 mEq/L, PaO2 94 mm Hg. How should the nurse interpret these results?

  1. AMetabolic alkalosis, uncompensated
  2. BRespiratory acidosis, partially compensated
  3. CMetabolic acidosis, partially compensated
  4. DRespiratory alkalosis, fully compensated
Show answer

Answer: C

The pH is below 7.35, so the client is acidotic. The bicarbonate of 14 mEq/L is low (normal 22 to 26), which matches the acidosis, so the problem is metabolic. The PaCO2 of 28 mm Hg is low because the client is blowing off carbon dioxide to raise the pH; that is the Kussmaul breathing you see in diabetic ketoacidosis. The pH is still abnormal, so compensation is partial, not full.

Why the others are wrong

Alkalosis requires a pH above 7.45. Respiratory acidosis would show a high PaCO2, not a low one. Respiratory alkalosis would have a high pH caused by the low PaCO2, and a fully compensated gas would have a pH back in the normal range.

Quick tips

  • Daily weight on the same scale, same time, same clothing is the single best indicator of fluid status. A gain or loss of 1 kg (2.2 lb) in 24 hours is about 1 L of fluid. Intake and output charts are useful but far less accurate.
  • Potassium and calcium are the two electrolytes that kill fast. If a potassium or calcium question offers an ECG change, a weak pulse or airway spasm as an option, that option is almost always the one to act on first.
  • Pair the opposites. Hypokalemia and hypercalcemia both slow things down (weakness, constipation, lethargy). Hyperkalemia, hypocalcemia and hypomagnesemia all make things twitchy and irritable (cramps, diarrhea, spasm, dysrhythmias).
  • For any ABG, go in the same order every time: pH first, then PaCO2 (respiratory), then HCO3 (metabolic). Whichever value points the same way as the pH is the cause, the other one is compensation.
  • Sodium corrections are slow in both directions. A fast fix for either hyponatremia or hypernatremia damages the brain, so when a question offers a rapid bolus or a large fluid push for a sodium problem, be suspicious of it.

Related topics

FAQ

what is the first thing you do for high potassium on the nclex

Check the client and the monitor first. If there are ECG changes (peaked T waves, wide QRS) or a weak irregular pulse, the first action is to protect the heart with IV calcium gluconate, then move potassium into cells with insulin and dextrose, then remove it with a binder or dialysis.

how do you remember chvostek vs trousseau

Chvostek is the cheek: tap the facial nerve and the face twitches. Trousseau is the tourniquet: inflate a blood pressure cuff above systolic for about 3 minutes and the hand curls into carpal spasm. Both mean low calcium (and sometimes low magnesium).

is daily weight or intake and output more accurate for fluid balance

Daily weight. One liter of retained or lost fluid is about 1 kg, and the scale catches fluid that never shows up on an I and O sheet, like sweat, wound drainage or fluid shifting into tissue. If a question asks for the best indicator of fluid status, pick daily weight.

Practice 10 free NCLEX questions every day in the DrillRN app

Every question comes with a full rationale that explains the right answer and why each wrong option is wrong.

Download on the App Store