Types of IV Fluids

what do we never give intravenously?

free, straight water

why dont we give straight water via IV?

water will go into places with higher solute concentration (cells), which causes cells to swell and burst

what are crystalloids?

clear fluids

types of crystalloid IV therapy fluids

• isotonic

• hypotonic

• hypertonic

isotonic solutions

total osmolality ~ equal to ecf

• fluid stays in the vascular space

• no net water shift in/out of cells

what happens to the size of cells when giving isotonic solutions?

nothing

• it stays the same because flow inside and outside the cell is perfectly equal

common examples of isotonic solutions

0.9% NaCl (normal saline), lactated ringer’s (LR)

typical uses of isotonic solutions

• dehydration

• sodium depletion

• GI losses (vomiting/diarrhea)\

• blood loss

• surgery

• — good for volume replacement

hypotonic solutions

have a higher water concentration

• dilutes ECF and moves water into cells → cells swell

what happens to the size of cells when giving hypotonic solutions?

they swell/get bigger

what happens to the vascular system when taking hypotonic solutions via IV?

shifts blood volume out of the vascular space and into cells

what can happen if you take hypotonic solutions too fast/much?

the patient can become hypovolemic (not enough blood volume, because all the fluid is in the fattened cells)

why might a patient be on hypotonic solutions?

• dehydratio

• severe hypernatremia (lots of sodium) when oral water isn’t possible

what cellular space is diluted in hypotonic IV therapy?

extracellular fluid (fluid outside the cell)

who would we avoid giving hypotonic IV fluids to?

patients with increased intracranial pressure

• risk of fluid shift into brain (detrimental)

rcmaples of hypotonic solutions

• 0.45% NaCl (aka half normal saline)

• 0.33% nacl

hypertonic solutions

fluids that pull water out of cells, into ECF/blood

what happens to the size of cells when giving hypertonic solutions?

cells shrink

what might happen if too much fluid leaves the cells?

it can cause fluid volume overload

• hypervolemia, higher blood pressure

what kind of patients are already prone to fluid overload (and can be made worse by taking too much hypertonic solution)?

patients with congestive heart failure (CHF) or renal dysfunction

what issues can be caused by not being careful with giving hypertonic solutions?

higher blood pressure, fluid overload complications

what are hypertonic solutions used for?

• significant hyponatremia (dilutes salt outside cells)

• cerebral edema (to reduce brain swelling)

common hypertonic solutions

• 5% dextrose in lactated ringer solution (D5LR)

• 5% dextrose in 0.9% NaCl (D5NS)

how is a hypo or hypertonic solution chosen for a patient?

depends on the patient’s specific fluid/electrolyte status