NRS 322 Lecture Notes - Lecture 5: Kidney Disease, Oncotic Pressure, Ascites
27 May 2018
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• Diffusion vs Osmosis
o Diffusion: movement of molecules from high to low concentration
o Osmosis: movement of water from an area of less concentrated molecules to higher
concentration of molecules
• Fluids in our body
o 1st space: Intravascular (blood stream)
o 2nd Space: intracellular
o 3rd space: sits outside the cell: interstitial space
• Three types of fluids
o Isotonic: equal. Tonicity of the fluid is equal to what we have in our blood.
▪ Normal Saline (NS) 0.9% saline.
▪ Really useful to us. It help can replace volume without shifting electrolytes around.
▪ Helps with volume issues
▪ LR: lactated Ringers solution. Na+, K+, Cl-, Ca++ and lactate similar to what we have in
our blood. We can use it if we have a lactate issue and want to give more.
▪ Ringers: same as LR without lactate. Older not used as often
▪ D5W: 5% dextrose in water. Starts out isotonic. Once the dextrose is used, all that is
left is water. The water is a hypotonic solution. We have to be cautious in how we use
it knowing it is going to change.
• We cant give large volumes of it
o Hypotonic: I have more solution than solutes
▪ Increase solution decreased solutes.
▪ Think of where the water is going to go to.
▪ Think osmosis: if injected into Intravascular space, it is going to go into the cell. This is
fine if the cells are dehydrated.
▪ Water moves into cells and they begin to swell.
▪ 1/2 NS: 0.45% saline. Water will move into the cells.
▪ 1/4 NS: 0.225% saline.
▪ D51/2 normal Saline sits in between isotonic and hypotonic. Very common solution
• You can always add electrolytes to this
o Hypertonic
▪ More solutes than H20
▪ Fluid will move out of the cells to the IV space. This causes the cell to shrink.
▪ Used when our brain is swelling.
▪ 3% saline-5% saline solution. We don’t use this ery often and hen e do e need to
monitor it very closely
▪ D10: 10% dextrose. It will pull water to it. Used when we are helping to regulate
sugars. More information when we get into nutrition.
• Hydrostatic
o Pushing pressure.
o Blood pressure.
o Force within fluid compartment
• Oncotic
o Pulling pressure
o Coloidal osmotic pressure
o What proteins do: pulls water to do it
• We want the two pressures to be equals
o If we have too much H and not enough O, we have swelling in the ___
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Document Summary
Diffusion vs osmosis, diffusion: movement of molecules from high to low concentration, osmosis: movement of water from an area of less concentrated molecules to higher concentration of molecules. Fluids in our body: 1st space: intravascular (blood stream, 2nd space: intracellular, 3rd space: sits outside the cell: interstitial space, three types of fluids. Tonicity of the fluid is equal to what we have in our blood: normal saline (ns) 0. 9% saline, really useful to us. It help can replace volume without shifting electrolytes around: helps with volume issues. Na+, k+, cl-, ca++ and lactate similar to what we have in our blood. We can use it if we have a lactate issue and want to give more: ringers: same as lr without lactate. Older not used as often: d5w: 5% dextrose in water. Once the dextrose is used, all that is left is water.
