Fluid Therapy

Question 1

How do you calculate total body water?

Answer 1

TBW= BW X 0.65
because the body is 65% water.

Question 2

The body is made of 65% water. There are two main compartments in which this water is contained. What are these compartments and how much water is within each?

Answer 2

1) intracellular (2/3)
2) extracellular (1/3)
- interstitial (75%)
- intravascular (24%)

Question 3

What is the general electrolyte composition of intracellular fluid?

Answer 3

LOW sodium
HIGH potassium

Question 4

What is the general electrolyte composition of extracellular fluid?

Answer 4

HIGH sodium
LOW potassium

Question 5

What electrolyte determines hydration status?

Answer 5

Total body sodium
the Na concentration determines IV volume. Water follows sodium

Question 6

T/F the serum sodium concentration reflect total body water NOT total body sodium content?

Answer 6

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.

Question 7

You have a patient that presented for anorexia. You run a CBC/Chem and see hyponatremia. How would you interpret this?

Answer 7

Releative water excess.
This patient is losing water and sodium through normal losses, but continuing to drink W/O replacing the sodium via food. This is causing water excess and making it appear that there is no sodium.

Question 8

You run a CBC/Chem that presented with polyuria. The results show a hypernatremia. What do you interpret from this?

Answer 8

There is a water deficit.

Question 9

What would be the outcome of a patient losing the following fluid types:
-Hypotonic
-Hypertonic
-Isotonic

Answer 9

-Hypotonic- Losing more water than solute could lead to hypernatremia
-Hypertonic: losing more solute than water could lead to hyponatremia
-Isotonic: unchanges Na

Question 10

What is the difference between dehydration and hypovolemia?

Answer 10

Dehydration 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.

Question 11

T/F the replacement fluid type for dehydration and hypovolemia is the same

Answer 11

True
High in NA, low in K

Question 12

What are indications to give a patient fluids?

Answer 12

1) dehydration
2) hypovolemia
3) Anorexia (<12-24 hr and expected to stay that way)
4) severe losses
5) general anesthesia
6) As a vehicle for other stuff like drugs

Question 13

What is the biggest difference between crystalloids and collids?

Answer 13

Crystalloids are essentially just salt water which gives them the ability to freely move within the extracellular space and redistribute into the interstitium rapidly. You can very safely give a large amount at a quicker rate.

Colloids contain molecules taht do not leave the intravascular space, and thus they will stay in teh IV space longer

Question 14

What are the 4 downsides to using colloids?

Answer 14

1) potential for interstitial leak and edema formation
2) changes coagulation (dec vWF, platelet aggregation and fibrin clot stability)
3) Kidney injury
4) Cost

Question 15

What are 4 examples of ISOTONIC fluids (fluids that have similar tonicity to the ECF)

Answer 15

1) LRS
2) Normal Saline ().9% NaCl)
3) Normosol R
4) Plasmalyte A/148

Question 16

T/F hypotonic fluids can be safely bolused.

Answer 16

False
Never bolus hypotonic fluids this will cause cellular edema and lysis.
They must be given slowly

Question 17

What are 3 examples of hypotonic fluids?

Answer 17

1) Normosol-M
2) 0.45% NaCl
3) Sterile water

Question 18

What are contraindications to using hypertonic saline?

Answer 18

1) hypernatremia
2) 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 (Cerebral edema)

Question 19

What is the difference between a balanced and unbalanced fluid?

Answer 19

balanced= major electrolytes (Na and Cl) are in similar proportion to the ECF. Meaning Cl is LOWER than Na. Examples are: LRS, Normosol-R, and Plasmalyte A/148

Unbalalanced= electrolytes are not in proportion with the ECF, so Na and Cl are closer in value. examples are Normal saline and 5% dextrose in water

Question 20

What is the difference between replacement vs maintenance fluids?

Answer 20

replacement mimics ECF becasue we are REPLACING what is lost, These fluids are HIGH in NA

Maintenance mimics daily requirements for electrolytes (LOW Na/Cl and HIGH K)

Question 21

What are examples of replacement fluid types?

Answer 21

LRS
Normal Sline
Normosol-R
Plasmalyte A/148

Question 22

What are examples of maintenance fluid types?

Answer 22

Normosol M
-.45% NaCl Saline
- D5W (5% dextrose in water)
- Home made
- plasmalyte B/56

Question 23

T/F oral fluids are best whenever possible

Answer 23

True if not possible IV is best

Question 24

T/F anything you can give IV you can give IO

Answer 24

True- IO admin is good for neonates or cardiovasularly collapsed patients.

Question 25

T/F subcutaneous fluids are appropriate in any situation there just less effective.

Answer 25

False- only appropriate in stable patients.

Question 26

What is the shock rate for crystalloids vs colloids?

Answer 26

Crystalloids – 10-20 mL/kG bolus
Colloids – 5-10 mL/kg Bolus

Question 27

What is the fluid rate for a dehydrated patient?

Answer 27

% dehydrated X BW (kg)= fluid deficit in L replace over 6-48 hours.

Once replaced add in maintenance fluids 30-60mL/kg/day

Question 28

T/F you should use a large diameter short length catheter for fluid boluses?

Answer 28

True- flow is proportional to the radius of the catheter and inversely proportional to the viscosity of the fluid and the length of the catheter.
For fast boluses want a large bolus and short catheter.

Question 29

What is the maintenace fluid rate?

Answer 29

BW x 30 +70= mL/day
Large breed= 40 mL/kg/day
Med= 50
Small= 60
Nenates= 80-100

Question 30

What are6 “complications” to fluid therapy?

Answer 30

1) electrolyte imbalances
2) fluid overload (edema)
3) iatrogenic heart failure
4) phlebitis
5) extra cost
6) prolonged hospitalization

Question 31

When should you discontinue fluids (3 scenarios).

Answer 31

when rehydration is complete
when patient is eating
when ongoing losses are undercontrol

Question 32

Which electrolytes can be supplemented in fluid therapy?

Answer 32

K
P
Mg

Question 33

How can we monitor a patient on fluid therapy to ensure we are not overloading them?

Answer 33

1) weight
2) USG

less sensitive:
3) PE
4) ins and outs
5) central venous pressure
6) left ventricular end-diastolic diameter
7) electrolytes