Fluid Therapy Flashcards
The body is made of 65% of water. There are TWO main compartments in which this water is contained. What are these compartments and how much water is within each?
- Intracellular (2/3)
- Extracellular (1/3)
- interstitial (75%)
- intravascular (25%)
How do you calculate total body water?
TBW = BW x 0.65
because the body is 65% water.
What is the general electrolyte composition of intracellular fluid?
LOW sodium
HIGH potassium
What is the general electrolyte composition of EXTRAcellular fluid?
HIGH sodium
LOW potassium
What electrolyte determines hydration status?
Total body sodium!
the Na concentration determines IV volume. Water follows sodium.
T/F: the serum sodium concentration reflects total body water NOT total body sodium content
true
water is freely moveable across cell membranes and sodium is not. therefore, if you see high Na on bloodwork, this means there is LOW body water (dehydration), does NOT tell you that there is too much sodium.
If you see low Na on bloodwork, it can be a relative excess of water and not truly a hyponatremia.
You have a patient that presented for anorexia. You run a CBC/Chem and see hyponatremia. How would you interpret this hyponatremia?
Relative water excess.
This patient is losing water and sodium through normal losses, but continuing to drink without replacing the sodium via food. This is causing a water excess and making it appear that there is no sodium.
You run a CBC/Chem on a patient that presented with polyuria. The results show a hypernatremia. What do you interpret from this?
There is a water deficit.
What would be the outcome of a patient losing the following fluid types:
- Hypotonic
- Hypertonic
- Isotonic
- Hypotonic: losing more water than solute could lead to hypernatremia
- Hypertonic: losing more solute than water could lead to hyponatremia
- Isotonic: unchanges Na
What is the difference between dehydration and hypovolemia?
Deydration is loss of fluid from the interstitial space. this occurs slowly over days-weeks and should/can be replaced slowly.
Hypovolemia is loss of fluid from the intravascular space and occurs much more rapidly, requiring a rapid restoration of blood volume.
T/F: the replacement fluid type for dehydration and hypovolemia is the same
True
high in Na, low in K
What are indications to give a patient fluids?
- dehydration
- hypovolemia
- anorexia (>12-24 hr and expected to stay that way)
- severe losses
- general anesthesia
- as a vehicle for other stuff (drugs)
What is the biggest difference between crystalloids and collids?
crystalloids are essentially just salt water which gives them the ability to freely move within the extracellular space and redistribute into the interstitium very rapidly. You can very safely give a larger volume at a quicker rate.
colloids contain molecules that do not leave the intravascular space, and thus they will stay in the IV space longer.
what are 4 downsides to using colloids?
- potential for interstitial leak and edema formation
- changes coagulation (dec vWF, platelet aggregation and fibrin clot stability)
- kidney injury
- cost $$$
What are 4 examples of ISOTONIC fluids (fluids that have similar tonicity to the ECF)?
- LRS
- Normal saline (0.9% NaCl)
- Normosol R
- Plasmalyte A / 148
T/F: hypotonic fluids can be safely bolused.
FALSE
never bolus hypotonic fluids. This will cause cellular edema and lysis.
They must be given slowly.
What are 3 examples of hypotonic fluids?
- Normosol-M
- 0.45% NaCl
- sterile water
What are contraindications to using hypertonic saline?
- hypernatremia
- dehydration
this is because hypertonic fluids pull free water from the interstitial and intracellular spaces to increase IV volume.
A good indication for this fluid type would be when you want to decrease cellular edema (ex. cerebral edema)
What is the difference between a balanced and unbalanced fluid?
balanced = major electrolytes (Na and Cl) are in similar proportion to the ECF. Meaning Cl is LOWER than Na. Examples of balanced fluids are: LRS, normosol-R, and plasmalyte A/148
unbalanced = electrolytes are not in proportion with the ECF, so Na and Cl are closer in value. Examples of unbalanced fluids are normal saline (0.9% NaCl) and 5% dextrose in water (D5W)
What is the difference between replacement versus maintenance fluids?
replacement - mimics ECF because we are REPLACING what is lost. These fluids are HIGH in Na.
maintenance - mimics daily requirements for electrolytes (LOW Na/Cl, HIGH in K)
What are examples of replacement fluid types?
LRS
Normal saline
Normosol-R
Plasmalyte A / 148
What are examples of maintenance fluid types?
- Normosol M
- 0.45% NaCl saline
- D5W (5% dextrose in water)
- home-made
- plasmalyte B / 56
T/F: oral fluids are best whenever possible
true!
although if not possible, IV is best.
T/F: anything you can give IV, you can give IO.
true – IO admin is good for neonates or cardiovascularly collapsed patients.
