CRNI Fluid and Electrolyte Balance 3 — Questions and Answers

Question 1: A patient receiving IV normal saline at 150 mL/hr develops crackles, jugular vein distension, and dyspnea. What is the priority nursing intervention?

Increase the head of bed elevation and continue monitoring
Slow or stop the infusion and notify the provider (Correct answer)
Switch to a hypotonic solution
Administer a fluid bolus to improve cardiac output

Correct answer: Slow or stop the infusion and notify the provider

These signs indicate fluid volume overload, requiring immediate reduction or cessation of the IV infusion and provider notification for diuretic orders.

Crackles (pulmonary edema), jugular vein distension, and dyspnea are hallmark signs of fluid volume overload (hypervolemia). The priority intervention is to slow or stop the IV infusion to prevent further fluid accumulation, then immediately notify the provider. Additional interventions include elevating the head of bed to 45 degrees, monitoring oxygen saturation, and preparing for potential diuretic administration (furosemide). The CRNI must calculate intake and output meticulously and recognize that elderly patients and those with cardiac or renal disease are particularly susceptible to fluid overload, even at standard infusion rates.

Question 2: Which electrolyte imbalance is MOST dangerous when administering potassium chloride IV?

Hypokalemia from too-rapid correction
Hyperkalemia from infusion rate exceeding renal excretion (Correct answer)
Hyponatremia from dilutional effect
Hypocalcemia from potassium-calcium antagonism

Correct answer: Hyperkalemia from infusion rate exceeding renal excretion

Hyperkalemia from excessive IV potassium infusion can cause fatal cardiac arrhythmias, making infusion rate monitoring critical.

IV potassium chloride carries a high-alert medication designation because hyperkalemia can cause lethal cardiac arrhythmias including ventricular fibrillation and asystole. The maximum recommended peripheral infusion rate is typically 10 mEq/hour (up to 20 mEq/hour via central line with cardiac monitoring). Concentrations exceeding 40 mEq/L peripherally cause phlebitis and pain. The CRNI must verify the rate, concentration, and route before infusion; never give IV push potassium; ensure adequate renal function; monitor ECG for peaked T waves, widened QRS, and prolonged PR intervals; and verify serum potassium levels during replacement therapy.

Question 3: What is the primary purpose of using an isotonic crystalloid solution for IV fluid replacement?

To shift fluid from the intracellular to the intravascular space
To expand the intravascular volume without shifting fluid between compartments (Correct answer)
To provide nutrition and caloric support
To promote cellular hydration through osmosis

Correct answer: To expand the intravascular volume without shifting fluid between compartments

Isotonic crystalloids have the same osmolality as plasma, expanding intravascular volume without causing osmotic fluid shifts between compartments.

Isotonic crystalloid solutions (0.9% NaCl, Lactated Ringer's) have an osmolality approximately equal to plasma (275-295 mOsm/L). When infused, they remain primarily in the extracellular fluid compartment without creating osmotic gradients that would shift water into or out of cells. Approximately 25% remains in the intravascular space while 75% distributes to the interstitial space. This makes them ideal for volume replacement in dehydration, hemorrhage, and surgical fluid losses. Hypotonic solutions (0.45% NaCl) shift fluid intracellularly, while hypertonic solutions (3% NaCl) draw fluid from cells into the vasculature.

Question 4: A patient's serum sodium is 118 mEq/L. What is the maximum safe correction rate to prevent neurological complications?

4-6 mEq/L per 24 hours
8-12 mEq/L per 24 hours (Correct answer)
15-20 mEq/L per 24 hours
Correct to normal as fast as possible

Correct answer: 8-12 mEq/L per 24 hours

Sodium correction should not exceed 8-12 mEq/L in 24 hours to prevent osmotic demyelination syndrome, a devastating neurological complication.

Osmotic demyelination syndrome (formerly central pontine myelinolysis) occurs when chronic hyponatremia is corrected too rapidly. Brain cells adapt to hyponatremia by expelling organic osmolytes; rapid sodium correction creates an acute hypertonic state in the brain, causing myelin destruction. The safe correction rate is 8-12 mEq/L per 24 hours (some guidelines recommend 8 mEq/L or less per 24 hours for high-risk patients). Treatment typically involves hypertonic saline (3% NaCl) administered via infusion pump with serum sodium monitoring every 2-4 hours. If correction occurs too quickly, the infusion must be slowed or desmopressin administered to prevent further correction.

Question 5: Which assessment finding indicates the patient is experiencing third-spacing of fluid?

Peripheral edema with low urine output and hypotension (Correct answer)
Hypertension with bounding pulses
Polyuria with increased specific gravity
Weight loss with dry mucous membranes

Correct answer: Peripheral edema with low urine output and hypotension

Third-spacing causes fluid to shift from the intravascular space into interstitial tissues, resulting in edema, intravascular depletion (hypotension), and decreased urine output.

Third-spacing refers to the pathological shift of fluid from the intravascular space into the interstitial (third) space where it becomes physiologically unavailable. This paradoxical state presents with visible edema (fluid accumulation in tissues) alongside signs of intravascular depletion: hypotension, tachycardia, decreased urine output, and elevated BUN/creatinine. Common causes include burns, pancreatitis, bowel obstruction, major surgery, and sepsis. The CRNI must recognize that despite apparent fluid excess (edema), these patients need intravascular volume replacement. Albumin infusion may be used to increase oncotic pressure and draw fluid back into the vasculature.

Question 6: What is the nursing implication of infusing hypertonic saline (3% NaCl)?

It can be safely administered through a peripheral IV
It requires central venous access and continuous cardiac monitoring (Correct answer)
It should be infused as a rapid bolus for maximum effect
It requires co-infusion with potassium replacement

Correct answer: It requires central venous access and continuous cardiac monitoring

Hypertonic saline is a high-risk infusion requiring central venous access to prevent phlebitis and continuous cardiac monitoring due to risk of rapid electrolyte shifts.

Hypertonic saline (3% NaCl, osmolality approximately 1026 mOsm/L) is a high-alert medication requiring stringent safety measures. It must be administered via central venous access because peripheral infusion causes severe phlebitis and potential tissue necrosis due to its hyperosmolality. Continuous cardiac monitoring is required because rapid sodium shifts can cause arrhythmias. An infusion pump is mandatory for precise rate control. Serum sodium must be checked every 2-4 hours during infusion, and the rate must not exceed the safe correction rate (8-12 mEq/L per 24 hours). Only ICU-level monitoring is appropriate for this therapy.

CRNI Fluid and Electrolyte Balance 3

A patient receiving IV normal saline at 150 mL/hr develops crackles, jugular vein distension, and dyspnea.
What is the priority nursing intervention?