kristalloidi

Kristalloidi are aqueous solutions containing small molecules that readily cross semipermeable membranes. In medicine they are used primarily for intravenous fluid therapy to replace lost fluids and electrolytes. They are contrasted with colloids, which contain larger molecules that remain mainly within the intravascular space.

Common kristalloidi include isotonic solutions such as 0.9% saline and balanced salt solutions like lactated Ringer’s or Plasma-Lyte. Hypotonic and hypertonic crystalloids are also used in specific indications. Dextrose-containing solutions (for example D5W) are crystalloids that provide calories; after metabolism these solutions behave as hypotonic fluids.

Pharmacodynamics and distribution: kristalloidi distribute quickly from the intravascular compartment into the interstitial space. They typically have a shorter intravascular persistence than colloids and may require larger volumes to achieve sustained plasma expansion, which can contribute to edema or electrolyte imbalances if not monitored.

Indications and practice: they are used for volume resuscitation in hypovolemia, dehydration, and as maintenance fluids. In critical care, balanced crystalloids are often preferred over normal saline due to potential metabolic and clinical advantages, though evidence varies by context.

Safety and considerations: potential risks include hyponatremia with hypotonic solutions, hyperchloremic acidosis with some saline solutions, electrolyte disturbances, and fluid overload in susceptible patients such as those with kidney or heart disease. Careful selection and monitoring of type, volume, and rate of administration are essential.

Terminology: the term kristalloidi refers to solutions of small osmotically active particles that readily cross membranes, distinguishing them from colloids used in intravenous therapy.