This pressure draws water through semipermeable membranes, such as a cell membrane. Responding to osmotic pressure, fluid can move into or out of the cell. The amount of osmotic pressure depends on the ratio between the concentration of ions in the infused solution and the concentration of ions in cell fluid. Water moves from an area of low ion concentration a hypotonic solution to an area of higher ion concentration a hypertonic solution.
When the number of protein molecules in plasma is low, such as in proteinuria seen with uncontrolled diabetes or protein-calorie malnutrition known as kwashiorkor, fluid moves into and stays in the interstitial spaces, where it's unavailable to meet the body's hydration needs. This is a type of third-space fluid shift , also called third-spacing. This condition sequesters fluid in the interstitial and intracellular spaces and in a third-body space such as the intestinal lumen where it doesn't support circulation.
Parenteral solutions are classified according to their tonicity relative to normal blood plasma. Here's how the three fluid types act in the body. That's why isotonic solutions such as 0. Because these solutions expand the intravascular compartment, closely monitor the patient for signs and symptoms of fluid overload, especially if he has a history of hypertension or heart failure.
Although D 5 W is isotonic in the bag, it acts like a hypotonic solution once it enters the bloodstream because simple sugars such as dextrose are the preferred energy source for cells. The low concentration of dextrose in D 5 W is quickly consumed by the cells lining the vein and circulating in the bloodstream. Use this solution with caution in patients at risk for increased intracranial pressure ICP. The liver converts lactate to bicarbonate, so don't give lactated Ringer's solution if the patient has a serum blood pH above 7.
Potassium chloride may be added in low concentrations to replace losses from the gastrointestinal system. When a hypotonic solution is administered, it puts more water in the serum than is found inside cells. As a result, water moves into the cells, causing them to swell. Although hypotonic solutions help replace intracellular fluid, the extra water also moves into the cells of the tunica intima of the vein at the catheter insertion site. IV fluid restores fluid to the intravascular compartment, and some IV fluids are also used to facilitate the movement of fluid between compartments due to osmosis.
There are three types of IV fluids: isotonic, hypotonic, and hypertonic. Isotonic solutions are IV fluids that have a similar concentration of dissolved particles as blood.
An example of an isotonic IV solution is 0. Because the concentration of the IV fluid is similar to the blood, the fluid stays in the intravascular space and osmosis does not cause fluid movement between compartments. See Figure Isotonic solutions are used for patients with fluid volume deficit also called hypovolemia to raise their blood pressure.
However, infusion of too much isotonic fluid can cause excessive fluid volume also referred to as hypervolemia. Hypotonic solutions have a lower concentration of dissolved solutes than blood.
An example of a hypotonic IV solution is 0. When hypotonic IV solutions are infused, it results in a decreased concentration of dissolved solutes in the blood as compared to the intracellular space.
This imbalance causes osmotic movement of water from the intravascular compartment into the intracellular space. For this reason, hypotonic fluids are used to treat cellular dehydration. However, if too much fluid moves out of the intravascular compartment into cells, cerebral edema can occur.
It is also possible to cause worsening hypovolemia and hypotension if too much fluid moves out of the intravascular space and into the cells. Therefore, patient status should be monitored carefully when hypotonic solutions are infused.
Hypertonic solutions have a higher concentration of dissolved particles than blood. When infused, hypertonic fluids cause an increased concentration of dissolved solutes in the intravascular space compared to the cells. This causes the osmotic movement of water out of the cells and into the intravascular space to dilute the solutes in the blood. Disclosure and Privacy Policy This website provides entertainment value only, not medical advice or nursing protocols. By accessing any content on this site or its related media channels, you agree never to hold us liable for damages, harm, loss, or misinformation.
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