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Renal and IV fluid basics Study Guide
IV Fluids:
Define solute, solvent, and solution.
- Solute: a particle, usually a salt, could be glucose
- Solvent: liquid, usually water that a solute floats in
- Solution: solute and solvent mixed together – like bag of fluids
Define osmolality, Osmosis, and semi-permeable membrane.Normplasmaosmolality
- Osmolality: measurement of amount of solute mixed per volume of solvent
o Normal for plasma is 275-295 mOsm/kg
- Osmosis: process of water moving across a semi-permeable membrane
- Semi-permeable membrane: only allows solvent to pass through, NOT solute
What are the 3 methods of fluid resuscitation?
- Crystalloid, colloid, or blood products
hiisotonichypotonic hypertonic
What type of fluids are BEST for fluid replacement (trauma, hemorrhage, etc.)?
- Isotonic solutions
What are examples of isotonic fluids?
- Normal saline
dextrose in NS or D5
NS DS LR
O-- 5%
Lactated ringers
o 5% dextrose in water or D5W is technically isotonic until the dextrose is metabolized, then
it’s hypotonic.
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Where do isotonic fluids go?
- To the vascular and interstitial space
What are hypotonic fluids and what’re they good for? z
- Basically water to dilute the vascular space: moves water INTO cell bc water follows salt
- Good for rehydration: N/V/D, DKA
What are examples of hypotonic solutions? 4
- 0.45% saline or ½ NS
- 0.33% saline or 1/3 NS
- 0.225% saline or ¼ NS
o D5W is hypotonic after it’s metabolized
What is important to watch for a pt on hypotonic solutions?
- Watch them carefully because fluid going into the cell can cause cell lysis
What are hypertonic solutions?
- Much more concentrated – pulls water out of the cell and into extracellular space
o Remember bc higher numbers (%) and if too hyper à lose weight
What are examples of hypertonic solutions?
- 3% and 5% saline
- 10% dextrose in water
- 5% dextrose in NS, ½ NS, and LR
gmos
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What is important to watch for hypertonic solutions?Never
givethese
- Watch for fluid overload and swelling
- Never give these without an order
What are additives and examples?
- Replacement electrolytes – come from pharmacy depending on what pt needs and are put in
solution
- K, Mg, Ca, Phos, and Bicarb
What are colloids?Wheredo
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- Much thicker + expensive (colloids
sounds richer) molecules that stay in the vein
- Plasma expanders
What are some example Colloids and when are they usually used? Why
- Dxtran and Hespan used b4 vascular surgery to expand volume
- Albumin 5% and 25% from blood bank
o Albumin is hypertonic as well
RENAL:
ACUTE KIDNEY INJURY:
What are the characteristics of AKI?
- Sudden, within a day or 2
- Potentially reversible
- Buildup of Nitrogen waste is bad:
o Increased Creatinine, with or without oliguria
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What is the normal amount of urinary output we want per hour and day?
- 30 mL/hour
- .5 mL/kg/hour
- 400 mL/day
perkg Hr
How many stages are there and how are those classified?
- 3 stages classified with RIFLE criteria (risk, injury, failure) – after that it’s end stage
What will u/o look like at stage 3?Howlong
- < 0.3 mL/kg/hour for 24 hours
What is the goal with AKI? 3 Avoid
- Find the cause of it and treat it and prevent further injury (no contrast, avoid hypovolemia)
List and describe/give examples of the 3 causes of acute kidney injury.
- PRE-RENAL: prior to hitting kidney, there’s damage
o Fluid deficit: blood loss, DKA, dehydration, trauma, burn, third spacing
o Sepsis, shock, anaphylaxis
- INTRINSIC: problem in the kidney itself
o Cellular lysis: cholesterol buildup, rhabdo, stenosis, tumor lysis syndrome
o Nephrotoxic agents cause acute tubular necrosis: NSAIDs, contrast, Vancomycin, viral
infections, Lupus/autoimmune
- POST-RENAL: problem AFTER the kidney
o
Obstruction: Foley cath kinked/clotted, cancer, BPH
CHRONIC RENAL FAILURE:
What are the characteristics of chronic renal failure? 3
- After 3 months of acute
- Gradual and progressive (can be unresolved AKI)
- Irreversible
What are the 1st, 4th, and 5th stages of CRF like?
- 1: least bad
- 4: chronic renal failure
- 5: end stage renal disease
What will GFR look like in all the 5 stages?
1. GFR could still be normal
2. 60-90
3. 30-60
4. 15-30
5. < 15: dialysis or die
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What are the main causes of CRF? z S
- Old age: increased wear and tear, increased risk for cancer, chemo is nephrotoxic
- e Comorbidities: DM (diabetic nephropathy), high glucose, cardiac probs like atherosclerosis, HTN, HF
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What will electrolytes look like with CRF?Na K Phos
- Na: low (it’s actually just diluted)
- K: high
- Phosphate: high
- Magnesium: high
- Calcium: looks normal but Vitamin D is not activated so Ca not used properly à weak bones
MgCa
What will BUN, Creatinine and GFR look like?
- Elevated BUN and Creatinine
- Decreased GFR (GFR calculated based on age, gender, and race)
What are the other manifestations of CRF? 6
indicatorofCRFstage3
- Urinary output can vary: oliguria presentKey
or not, can also have anuria or a diuretic effect
- Fluid retention: the KEY INDICATOR of chronic renal, or at least stage 3 failure
- HTN: caused by retention
- Fatigue/lethargy: electrolytes are messed up
- Acidosis: Bicarb not produced
- Anemia and platelet dysfunction: kidneys make erythropoietin but that’s ruined so decreased Hgb
AND dialysis can cause loss of blood à confusion and neuro symptoms occur if pt skips dialysis
What labs/diagnostics will you do and what might they show? 4
- BUN/C: high, GFR low
- Urinalysis: may see protein in urine and specific gravity + osmolality are increased
- Renal u/s: shows size, shape, and blood flow of kidneys
- Pyelogram and CT: both use contrast so you’d better have a good reason to do (blockage maybe)
What is the first way to treat CRF?
- Find the cause.
o Stop nephrotoxic meds
How else can it be treated? 6
- Adjust the dose with known renal clearance
- Discontinue K orders: treat DKA, but know K is already high
- Target euvolemia: don’t overuse diuretics but know they’re fluid overloaded
- Treat acidosis and hyperkalemia: give Bicarb
NaHC03
- Consider phosphate binders to lower phosphate
- Consider dialysis: small fixes won’t work forever. Low GFR won’t kill you; it’s the electrolyte
imbalance that’ll do it
What will dialysis do for CRF pts?
2things
- Improve GFR and lower Creatinine
How could you treat potassium?
4
- Change diet if hyperkalemia is not urgent
- Cation-exchange resin: Kayexolate is a diuretic for K so it’ll treat it quickly
- Insulin/glucose (for the insulin), Ca, and Bicarb: pushes K back into the cell to lower the effects of K
and Bicarb fixes acidosis
- Dialysis
if
How can H&H be fixed? What
give necessary
might
- Replace Hgb: know a transfusion is contraindicated bc it makes the body stop making erythropoietin
o Only do transfusion if necessary – give Procrit (basically erythro.) to stimulate body to make
RBCs AND give iron supps
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Describe a renal diet. 5 Howshouldsuppsbe
given
- Na < 2 grams daily
- Take Calcium supplements like Tums and Ca Acetate (aka Phoslo)
o Give Phoslo 3x/day with meals
- Avoid Mg in diet and in meds
- Keep phosphate < 1,000 in diet
- Keep K < 40 mEq
How does Phoslo work and what happens with it?
- Binds to phosphate and excretes phosphate through the stool
- Turns poop white and makes you constipated sometimes
DIALYSIS:
What are some signs you should progress to dialysis? 4
- High K+ or acidosis present even with interventions
- If bicarb is contraindicated and cannot fix acidosis
- Uremic state with neuro symptoms
- Excessive fluid overload
or GFR
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There are 3 types of dialysis: hemo, peritoneal, and CRRT. What’s the purpose of dialysis?
- To excrete the bad stuff and filter the electrolytes we don’t need. It won’t fix their kidneys, but
without it they will die so it’s supportive tx.
how
pions
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Describe continuous renal replacement therapy (CRRT) – who, how it runs, and considerations.
- For acute renal pts – it’s slower and gentler, requires vascular access. However, bc it’s slower, it can
clot off so keep the pt anticoagulated. If it does clot, try to return as much blood as possible because
it can drop Hgb.
- Considerations: watch BP and clotting
- Can run over 12 hours – be sure to wean off
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What is an important consideration about Heparin and pts with CRRT dialysis lines?
- The red and blue lines are locked with Heparin, so you need to draw that off before anything is put in
those lines. Therefore, it’s not really used to push meds.
done
Where
How does hemodialysis work? How long is it? Who
is it best for? What to watch for?Usedas
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- Blood filtered thru semi-permeable membrane and exposed to Dialysate then goes back in
- Not done at home d/t BP and clotting risks
- Takes 30 minutes – 4 hours, used as long-term tx plan
How does peritoneal dialysis work? Where is it done? Considerations? risk
- Fluid in the peritoneal cavity is drawn off which pulls off the toxins and bad stuff
- Can be done at home – may have to rotate to get the fluid off
- Cath is placed in the abdomen = risk for peritonitis (infection)
What should be done with all types of dialysis?
- Weight before and after
What’re the 2 types of peritoneal dialysis?
- Continuous ambulatory peritoneal dialysis: outpatient, they’re able to ambulate
- Continuous cycler-assisted peritoneal dialysis: @ night with a pump
What are the 2 types of short term vascular access???Whichcan
w t cannot
gohome
- Shiley: name brand dialysis cath where red is arterial and blue is venous
– can’t go home with
- Tunnelled cath: for longer use: pt can go home with it
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What are the considerations?
- Placement: may put pt at risk for infection, especially femoral
- Watch for infection, do sterile dressing changes, and use clear dressings
What will be done for long-term vascular access? How does it work?
- Surgery to form an AV fistula or AV graft – these create turbulent flow to pull blood off easily
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What are the post-op considerations for fistulas/grafts?
- Assess site for infection, cap refill, color (may not feel if they had a block bc anesthesia is avoided
- Feel for thrill and listen for bruit – notify HCP if you can’t hear it
- Keep extremity elevated, watch for bleeding
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What is good education for dialysis pts?
p (proteins are hard for kidney to filter)
- Renal diet: low Na, K, phos, fluid, and proteins
- Access site care and clean
- Schedule appts, follow up on labs, and seek support