NCLEX IV Fluid Solutions: Side-by-Side Comparison & Quick-Lookup

Comprehensive vocabulary flashcards covering IV fluid tonicity categories, clinical indications, contraindications, fluid shifts, and nursing priorities based on NCLEX review guidelines.

Isotonic Solutions

IV solutions with an osmolality equal to normal blood plasma ($\sim 275\text{--}295\,\text{mOsm/L}$) that cause no net fluid shift, remaining inside the blood vessels (intravascular/extracellular space) and keeping cell size unchanged.

Hypotonic Solutions

IV solutions with a lower solute concentration than normal blood plasma ($< 275\,\text{mOsm/L}$) that drive water out of the blood vessels and into the cells, causing cells to swell with a risk of cellular lysis or bursting.

Hypertonic Solutions

IV solutions with a higher solute concentration than normal blood plasma ($> 295\,\text{mOsm/L}$) that pull water out of the cells and into the blood vessels, causing cells to shrink (crenate).

"Iso stays"

A memory trick for isotonic solutions indicating that the administered fluid stays where you put it (within the intravascular space).

"Hypo makes cells swell & break"

A memory trick for hypotonic solutions highlighting that lower extracellular osmolarity forces fluid into intracellular compartments, risking cell swelling and lysis.

"Hyper takes & cells shrink"

A memory trick for hypertonic solutions denoting that higher intravascular osmolarity draws fluid out of cells, causing them to shrink.

0.9% Sodium Chloride (Normal Saline / NS)

An isotonic solution indicated for dehydration, acute blood loss, hemorrhage, shock, trauma, and initial DKA resuscitation; it is the only fluid compatible with blood products, but massive infusions carry a risk of hyperchloremic acidosis.

Lactated Ringer's (LR)

An isotonic crystalloid used for burns, surgical fluid loss, trauma, and acute blood loss; contains potassium ($\sim 4\,\text{mEq/L}$) and lactate (converted to bicarbonate by the liver), and is contraindicated in renal failure, hyperkalemia, and severe liver disease.

D5W (5% Dextrose in Water)

A solution that is isotonic in the IV bag but acts hypotonic in the body once dextrose is metabolized; used for hypernatremia and free water replacement, but contraindicated in increased ICP, head trauma, fluid overload, and hyperglycemia.

0.45% Sodium Chloride (Half-NS)

A hypotonic IV solution used for cellular dehydration, hypernatremia, and DKA/HHS after initial $0.9\%\,\text{NS}$ stabilizes blood pressure; contraindicated in increased ICP, head trauma, burns, and acute hypovolemia.

0.33% or 0.225% Sodium Chloride

Very hypotonic IV solutions indicated for severe hypernatremia and maintenance fluids in specific pediatric or renal cases; carries a high risk of rapid intracellular fluid shifts and hemolysis.

3% or 5% Sodium Chloride

Hypertonic saline solutions used for severe symptomatic hyponatremia and acute cerebral edema; must be infused slowly via an IV pump (typically requiring a central line) while monitoring sodium closely.

D10W (10% Dextrose in Water)

A hypertonic solution used for hypoglycemia, parenteral nutrition, and caloric support; requires frequent blood glucose checks and must not be stopped abruptly to prevent rebound hypoglycemia.

D5 0.9% NaCl / D5 0.45% NaCl / D5LR

Hypertonic combination solutions used for maintenance fluids with calories and in DKA management once blood glucose drops to $\sim 250\,\text{mg/dL}$; contraindicated in severe hyperglycemia, renal failure, and heart failure.

Osmotic Demyelination Syndrome (ODS)

A severe neurological complication caused by the overly rapid correction of low serum sodium ($\text{Na}^+$) levels when administering hypertonic saline.