IV Maintenance Flashcards
Body fluid breakdown
-Body is 60% water
-In two compartments (ICF, ECF)
-2/3rds of all fluid within body in cells (ICF)
-1/3rd outside cells (ECF)
ECF 3 compartments
-Interstitial (fluid between cells and outside blood vessels)
-Intravascular (blood plasma)
-Transcellular (fluid separated from other fluid by epithelium = a thin tissue forming outer layer of structure)
Example of transcellular fluid
-Include CSF, pleural, peritoneal, synovial, and fluids in GI tract, intraocular, pericardial fluid
Osmosis
-The movement of water through a semipermeable membrane from an area of lesser solute concentration to an area of greater solute concentration
-A semipermeable membrane allows water (solvent) to flow through but not salt (solute)
-Fluid will continue to shift until an equilibrium is reached
Osmotic Pressure
-Pressure needed to counter the movement of water across a semi permeable membrane from a low to high concentration of solutes
-Force opposing osmosis
Colloid osmotic (Oncotic) Pressure
-Pressure in the body that keeps fluid in the intravascular compartments by pull water from interstitial space back into the capillaries
-Plasma proteins (albumin, globulin, fibrinogen) affect the bloods osmotic pressure
-Low albumin will get leaking of fluid into the interstitial space = edema
Hydrostatic Pressure
-The opposing pressure to Oncotic pressure
-It is the force within a fluid compartment that pushes water out of the vascular system at the capillary level
-In the blood vessels, hydrostatic pressure is the blood pressure generated by the contraction of the heart
1st Spacing
-Is the normal distribution of fluid in the ICF and ECF compartments
-Fluid moves freely between these spaces to maintain fluid balance
2nd spacing
-An abnormal accumulation of interstitial fluid
-Eg. Edema
-Fluid is still in contact with the area it’s suppose to be in so fluid can easily move back into 1st spacing areas through osmosis, hydrostatic pressure, & diffusion
3rd Spacing
-Fluid accumulates in a portion of the body from which it is not easily exchanged with the rest of ECF =fluid is trapped and unavailable
-Eg. Fluid shifting associated with burns and ascites
What are IV Infusions
-Instillation of fluid, electrolytes, medications, blood, or nutrients into a vein
-May be ordered to supply supplemental or complete fluid, electrolytes, nutrition, administer blood or blood products, provide vitamins and medications or establish a lifeline for rapidly needed medications
NS
-Normal Saline
-0.9% NaCl
1/2 NS
-Half strength normal saline
-0.45% NaCl
1/3 NS
-One third strength normal saline
-0.33% NaCl
LR or RL
-Lactated ringers or Ringers lactate
D5W
-5% dextrose in water
D5NS
-5% dextrose and normal saline
-5% dextrose & 0.9% NaCl
D51/2NS
-5% dextrose and half strength normal saline
-5% dextrose & 0.45% NaCl
2/31/3
-Two thirds dextrose and one third normal saline
-3.3% dextrose & 0.3% NaCl
IV Solutions: Crystalloids
-Contains solutes that cross semipermeable membranes
-They have 3 different tonicities: hypotonic, isotonic, hypertonic
-Can also be categorized by purpose (ie. electrolytes or nutrient)
IV Solutions: Colloids
-Contain a protein or starch which does not cross the semipermeable membrane so it remains in the intravascular space
-Colloids are used to increase osmotic pressure to increase vascular volume (they draw fluid in and keep it in the vein so the patient has more circulating volume for the heart to pump)
-Also called a volume or plasma expander
Examples of Colloids
-Albumin, pentaspan, voluven
When are colloids used
-Used short term in critically ill patients
-For conditions such as hemorrhaging, or burns which draw large amounts of plasma from the bloodstream to the burn site
Osmolarity
-Term used to refer to the concentration or the amount of solute in fluids outside of body (such as IV solutions)
-Measured in milliosmoles per litre (MOsm/L)
Osmolality
-Refers to the concentration of fluids inside the body (blood plasma)
-Measureed in millimoles per kilogram (mmol/Kg)
-Measures concentration of plasma and tells us about fluid/electrolyte balance
-Normal serum osmolality is 280-320mmol/kg
-If increased that means the blood is concentrated and there is a state of dehydration
-If decreased that means the blood is dilute and there is a state of over hydration
If you compare the concentration of an IV solution to the concentration of blood serum…
-Will tell you if/how fluid will shift once it’s infused into the body through IV catheter
Isotonic IV solutions
-Have the same concentration of solutes as the blood plasma
-Osmolarity ranges from 250-375
-So fluid stays in intravascular space
-Used to restore vascular volume, more fluid for heart to pump around and more fluid for kidneys to filter so watch for hypervolemia
Examples of Isotonic Solutions
-NS
-LR
-D5W
D5W ..
-Is chemically (in the bag) isotonic, but clinically (in the body) hypotonic
-D5W fluid quickly becomes hypotonic as the dextrose is metabolized
-Insulin pulls the glucose into the cell leaving free water in the intravascular space
-The water then quickly shifts from the intravascular space to the cells by osmosis like any other hypotonic solution
Hypotonic IV Solutions
-Have a lesser concentration of solutes than plasma
-Osmolarity is less than 250 mOsm/L
-Lower the Osmolarity/osmotic pressure within the intravascular space so fluid shifts out of the intravascular space into intracellular/interstitial space (cells enlarge)
Hypotonic Solutions are Used for
-To provide free water
-To treat cellular dehydration
-Dilute excess electrolytes as in hyperglycemia (because solvent > solute)
Examples of Hypotonic Solutions
-1/2 NS
-1/3 NS
Do not give hypotonic solutions to …
-Patients with increased ICP or 3rd space fluid shifting
What to watch for when giving Hypotonic solutions
-Watch BP as fluid is pulled out of the intravascular space and monitor for edema
Hypertonic IV Solutions
-Have a greater concentration of solutes than plasma
-Osmolarity is >375 mOsm/L
-Cause a higher osmotic pressure in the plasma which pulls fluid from the intracellular/interstitial space (cells shrink) into the intravascular space expanding vascular volume
What are hypertonic solutions used for
-Used to correct electrolyte imbalances as in loss from excess vomiting or diarrhea
Examples of hypertonic solutions
-D10
-3% NS
-D5NS
-D51/2NS
-D5LR
Caution: Hypertonic solutions
-Use caution with patients with kidney or heart disease or who are dehydrated (giving fluid into vascular space but drying out the cells)
-Watch for hypervolemia
-Because of elevated Osmolarity in comparison to normal blood serum, hypertonic solutions can be very irritating to veins
D5NS
-chemically hypertonic becomes just NS (which is isotonic) once the dextrose is metabolized
D51/2NS
-Chemically hypertonic, becomes just 1/2 NS (which is hypotonic) once the dextrose is metabolized