Hypertonicity

Definition

Hypertonicity refers to solutions with a higher solute concentration (higher osmotic pressure) than plasma, causing cells to shrink as water moves OUT of cells into the hypertonic solution. It can also describe increased muscle tone (spasticity).

Hypertonic IV Solutions

• 3% NS (used for severe hyponatremia)
• D5NS (after being in body, D5 metabolizes)
• D10W
• TPN

Clinical Indications

Severe hyponatremia, cerebral edema, fluid shifts. Administer slowly, monitor for fluid overload, pulmonary edema, and central line placement usually required.

Contraindications

Cardiac/renal disease with risk of overload. Avoid rapid sodium correction (cerebral demyelination risk).

Nursing Considerations

Monitor electrolytes, vital signs, lung sounds, never use hypertonic saline peripherally for extended periods (vein irritation).

NCLEX Relevance

Hypertonic fluids: use central line; monitor for overload.