Fluids Flashcards
Why do we replace fluids
to maintain homeostasis
What is total body water
60% of total body weight
2/3 ICF, 1/3 ECF (of the ECF, 3/4 is interstitial, 1/4 is plasma)
Newborns have the most (80%)
In adults, M>W (more adipose= less water)
How do we remember fluid levels
TIE 60 40 20
What ions are intracellular
Potassium
PO4
protein
magnesium
What ions are extracellular
Sodium
Chloride
HCO3
What do we need to know about daily water balance
Input should equal output (Euvolemia)
Output is usual insensible loss (lungs, skin NOT sweat), sweat, feces, urine
What causes hypovolemia
GI loss (vomit, bleeding, diarrhea) Renal loss (diuretics, diabetes insipidus) Skin loss Sequestered w/ loss (rhabdo, pancreatitis)
What are symptoms of Hypovolemia
thirst decreased sweating/skin turgor DMM Oliguria (concentrated pee) CNS depression weakness, muscle cramps Hypotension Tachycardia
What is third spacing
fluid in the interstitium (where it shouldn't be) AKA edema (ascites, burns, pleural effusion)
What is significant about third spacing
They can still be hypovolemic
What are the types of fluids
Crystalloid (electrolytes, pass thru endothelial membrane, water follows) Colloid (lytes and org. molecules, don't pass endothelium, stay in intravascular space) Blood products (like colloids, stay in vascular space)
What is the most common fluid used
Crystalloid- it’s isotonic
What are types of crystalloids
Isotonic (name Na as normal cells): LR, 0.9% NS, plasma-lyte- distribute evenly thru ECF
Hypertonic (higher salt than our cells): 3% NS
Hypotonic (lower salt): 0.5%, 0.25% NS
Dextrose 5% in water (D5W)/ D5 1/2NS
What is in isotonic crystalloids
LR: lactate, K+, Ca, NaCl
plasma lyte: less Chloride to prevent acidosis (more physiologic)
What are Isotonic crystalloids used for
dehydration
hypovolemia
hypovolemic shock (CAN IV BOLUS)
What are hypertonic crystalloids used for
life threatening hyponatremia (causing seizure)
To decrease cerebral edema in neurosurg patients
Why do we need to be careful with hypertonic crystalloids
If administered too quickly can cause CPM
What are hypotonic crystalloids used for
maintenance fluid- they distribute thru TBW so not good for replacing INTRAvascular fluid deficit, dehydration, or hypovolemia
What is D5W used for
hypoglycemia
hypernatremia w/ free water deficit
(distributes like hypotonic- caution in DM patients)
Colloids are basically
likely to expand vascular compartment- use them when crystalloids fail to sustain plasma volume 2/2 decreased osmotic pressure
Who would colloids be beneficial in
burn pts
peritonitis (protein loss)
malnourished
(NOT for severe hypovolemia)
What are the types of colloids
Albumin (5%, 25%)
Dextran and Hetastarch (not used a lot)
When is albumin used
In edematous patients, to mobilize interstitial fluid (NOT if albumin >2.5 mg)
Liver disease
peritonitis
burns
3rd spacing
–AKA, we want to try to shift fluid to intravascular space from the interstitium
What are blood products
Packed RBC*
platelets
FFP
cryoprecipitate
What are packed RBC and when are they used
Made from whole blood, they stay in vascular space
Used for transfusion to increase oxygen to tissues (hemorrhage or severe anemia)
1 PRBC unit will increase Hgb by 1g
What do patients need if they get packed RBC
Type and screen (blood type)
Type and cross (at time of transfusion to specifically check for a reaction)
When are platelets used
to prevent or treat bleeding In patients with:
thrombocytopenia
bad platelet function (on ASA/plavix)
What is FFP and when is it used
Has all factors of soluble coagulation system.
Used to correct major bleeding if patient is on warfarin OR hypokalemic
Also in hereditary angioedema
What is the difference between FFP and vitamin K
FFP works right away but is only effective for a short time
Vitamin K takes a while to be effective but lasts way longer
What is cryoprecipitate and when is it used
Thawed FFP and collect precipitate- has higher fibrinogen and factor 8, factor 10, and VWF
Use if low fibrinogen d/t massive hemorrhage, liver failure, or consumptive coagulopathy
What is a bolus
1 large amount (250mL-1L) isotonic crystalloids (2/2 hypovolemia) Packed RBC (2/2 massive hemorrhage)
Who do we need to use caution in when giving a bolus
Heart Failure patients (may already be fluid overloaded)
What are maintenance IV fluids
they account for ongoing water and electrolyte loss, under normal physiologic conditions (urine, feces, sweating, respirations)
- we give them when patients are not eating or drinking normally, to maintain balance
- NS, plasma lyte, LR, D5 1/2NS +/- 20mEq KCl
How do we calculate rate at which to give maintenance fluids (adults)
based on the clinical scenario! usually:
1st 10kg= 100 mL/kg
2nd 10kg= 50 mL/kg
rest= 20 mL/kg
divide all by 24 hours and you get your average hourly infusion rate
Most hourly infusion rates are
75 ml, 100 ml, 125 ml
if you get a weird number thru calculation, ROUND
What can you add to maintenance IV fluids
K to treat hypokalemia (potassium is osmotically like Na)
BUT, you cant bolus potassium. so if you add K to 0.9% NS, you can no longer bolus
also, use caution with K in renal disease patients
How are replacement IV fluids used
to correct existing water/electrolyte deficiency d/t pathologic conditions
must monitor vitals, UO, and clinical picture
use CAUTION if very hypo or hypernatremic (correcting too fast can lead to CPM)
Who often needs replacement fluids
surgical patients (low UO, 3 spacing, blood loss, etc.)
What is parkland formula (burn patients)
total fluid needed in first hour= (% of 2-3 degree burn) x (kg) x 4mL replace with LR! first 8 hr: 1/2 of total fluid 8 hr: 1/4 of total 8 hr: 1/4 of total
What is the rule of 9’s
Head: 9 Arms: 9 each legs: 18 each front torso: 18 back: 18 perineum: 1
