F&L Quick Notes: IV Solutions
Isotonic solutions
• Definition: when solutions on both sides of a selectively permeable membrane have
established equilibrium or are equal in concentration, they are isotonic.
• Human blood is isotonic thus very little osmosis occurs since isotonic solutions have
the same osmolality as body fluids & thus increase extracellular fluid volume.
Memory Trick:
• Iso-tonic Solutions
• I-so-Perfect (no fluid shift, “I’m so perfect” perfect balance)
• List of fluids:
• 0.9% sódio, chloride (normal saline)
• 5% dextrose in water (DWS)
• 5% dextrose in 0.225% saline (DSW/ 1/4 NS)
• Lactated Ringer’s (LR)
Hypotonic solutions
• Definition: when a solution contains a lower concentration of solute than another
more concentrated solution, then it is a hypotonic solution.
• These solutions have lower osmolality than body fluids.
• They cause the movement of water into cells by osmosis, swelling the cells like a BIG
fat hippo, and therefore should be administered slowly to prevent cellular edema
Memory Trick:
• HypO - tonic
• HippO - tonic = fluid swells the cell like a big hippo
• List of fluids:
• 0.45% sodium chloride (1/2 NS)
• 0.225% sodium chloride (1/4 NS)
• 0.33% sodium chloride (1.3 NS)
Hypertonic solutions
• Definition: when a solution contains a higher concentration of solutes than
another less concentrated solution, then it is a hypertonic solution.
• These solutions have higher osmolality than body fluids
• They cause the movement of water outside the cells by osmosis, making the
cells skinny like a hyper person.
Memory Trick:
• Hyper - tonic
• Hyper person = very skinny cells like a hyper person is skinny
• List of fluids:
• 3% sodium chloride (3% NS)
• 5% sodium chloride (5% NS)
• 10% dextrose in water (D10W)
• 5% dextrose in 0.9% sodium chloride (D5W/NS)
• 5% dextrose in 0.45% sodium chloride (D5W/ 1/2 NS)
• 5% dextrose in Lactated Ringer’s (D5LR)