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How much of the adult human body is made up of water? Older adult? Embryo?
- Adult- 60% 40L
- Older adult- 45-55%
- Embyro- 97%
- Newborn- 70-80%
How much of the water fluid is intracellular fluid and extracellular fluid?
- Intracellular: 40%
- Extracellular: 20%
What is Omolality:
- Osmotic pull exerted on all particles per unit of water. Number of osmoles per kg of water (mmol/kg or mOsm/kg. Number of particles dissolved in the serum, primarily sodium, urea (blood urea nitrogen BUN) and glucose. Also is a measure of concentration of solutes per kg in urine.
- Concentration of particles in a solution and is used in reference to body fluids
- Iso-osmolar fluid: Same proportion of weight of particles (Na, glucose) & water
- Hypo-osmolar fluid: Fewer particles than water
- Hyperosmolar fluid: More particles than water
What is the main function of sodium in the body?
The main extracellular electrolyte whose major function is to regulate body fluids; also promotes transmission and conduction of nerve impulses. Combines readily with chloride (Cl-) and bicarbonate (HCO3-) to promote acid-base balance. Also part of sodium/potassium pump
What is the normal serum osmolality related to sodium?
- 280-300 mOsm/kg
- Hypo-osmolar: Body fluid with <280 mOsm/kg
- Hyperosmolar: Body fluid with >300 mOsm/kg
What is tonicity and how does it affect osmolality?
- Used primarily as a measurement of the concentration of IV solutions compared with osmolality of body fluids
- Describes the ability of a solution to cause a cell to gain or lose water
When is fluid replacement indicated?
- IV fluids are ordered based on an evaluation of the patients fluid and electrolyte balance, fluid requirements and fluid needs.
- Illness and surgery increase the amount of fluids lost and affect fluid and electrolyte needs.
What is the isotonicity range of an IV solution?
280-300 mOsm/L; they have the same approximate osmolality as ECF or plasma; because of osmotic equilibrium water does not enter or llve cell-no effect on RBCs
What is an IV hypotonic solution? Hypertonic solution?
- Hypotonic solution: exert less osmotic pressure than ECF, which allows water to move into the cell.
- Hypertonic solution: exert greater osmotic pressure than ECF, resulting in higher solute concentration than the serum. Pulls water from interstitial space to ECF via osmosis ad cause cell shrinkage.
What IV solutions are considered isotonic and when would they be needed?
- D5W (5% Dextrose and water)
- Normal saline
- Lactated ringers
- Used for hydration and to expand ECF volume, because the fluid remains in intravascular space.
What are the four classifications of IV solutions?
- Crystalloids: contain fluids and electrolytes able to freely cross capillary wall
- Colloids: called volume expanders
- Blood and blood products
When would crystalloids be used and what IV solutions are included in this classification?
- Used to treat dehydration and electrolyte imbalances and as short-term maintenance fluids.
- 3 major classifications of crystalloid IVFs: isotonic, hypotonic & hypertonic
When would colloids be used and what IV solutions are included in this classification?
- Colloids contain protein or other large molecular substances that increase osmolarity w/out dissolving in the solution. Because of their size the particles are unable to pass though the semipermeable membranes of capillary walls and stay w/in intravascular compartments; so colloids are known as plasma expanders.
- They act by increasing colloidal oncotic pressure and pulling fluids from interstitial space into plasma, increasing blood volume.
- Solutions: high molecular weight dextran, low molecular weight dextran, hydocyethyl starch & albumin
What are the different types of blood products and when would each be used?
- Include whole blood and the components that can be processed through centrifugation methods. Include packed RBC, plasma, platelets, and cryoprecipitate.
- Plasma can be further processed into volume expanders, coagulation factor concentrates and immune globins
When would lipids be utilized for IV therapy? TPN?
- Indicated for patients who cannot tolerate enteral feedings for 7 days of more.
- PN provides proteins, carbs, electrolytes, trace minerals, and vitamins. TPN (Total nutrient admixture) includes lipids (pt must have a centrally or peripherally inserted vascular access device to receive PN formulas)
What are the daily water requirements of a normal adult?
3.7 L for man, 2.7 L for woman;
How would you calculate the daily water need for a person in kilograms? Pounds?
How much is the need for water increased in a person with a fever?
While administering water to a pt with fever, the water needs to be increased by 15 percent
How much fluid does a person lose each day by:
- Skin evaporation = 450 mL
- Breathing = 350 mL
- Feces = 200 mL
- Urine = 1400 mL
When a person is on IV fluids for over 24 hours what would be the need for more than one type of IV solution?
Different types and concentrations of IVFs are available to replace body fluid losses. Different types are used to balance the electrolyte needs of the pt