Fluids

Question 1

What fraction of body water is intracellular?

Extracellular?

Answer 1

Intracellular: 2/3
Extracellular: 1/3

Question 2

The “first space” corresponds to?

Answer 2

Intravascular compartment

Question 3

The “second space” corresponds to?

Answer 3

Intracellular space

Question 4

The “third space” corresponds to?

Answer 4

Where fluid does normally accumulate (pleural cavity, peritoneal cavity, edema in extracellular space)

Question 5

T/F? Fluids, electrolytes, and medications are not bioavailable in the third space

Answer 5

True

Question 6

Define maintenance fluid therapy.

Answer 6

Replacement of ongoing losses of water and electrolytes under normal physiologic conditions

Question 7

Define fluid replacement therapy.

Answer 7

Correction of existing water and electrolyte deficits.

Question 8

Why do we care about a patients hydration status?

Answer 8

Dehydration causes decreased organ perfusion leading to organ damage

Question 9

What factors lead to hypovolemia in surgical patients?

Answer 9

Patients are NPO prior to and post surgery
Blood loss from surgery
Third spacing in surgery

Question 10

What fluid is the most physiologic replacement?

Answer 10

D5 1/2NS

Question 11

What is the maintenance dose for fluids for a 90 kg patient?

Answer 11

120ml/hr
100ml/kg for first 10kg = 1000ml
50ml/kg for second 10kg = 500ml
20mg/kg for each kg over 20 kgs = 20 x 70 = 1400
1000+500+1400 = 2900
2900/24 hours = 120.83

Question 12

Calculate the hourly maintenance dose of fluids for a 50 kg patient using the 4/2/1 rule.

Answer 12

4ml for kg 1-10 = 4x10 =40
2mk for kg 11-20 = 2x10=20
1ml/kg for each kg over 21
30x1 = 30
40+20+30 = 90ml/hour

Question 13

Dehydrated patients need fluid replacement. How do you calculate how much replacement they need?

Answer 13

Estimate deficit.
Calculate real weight
Calculate deficit in kg
Add to maintenance dose

Question 14

Estimate the fluid deficit for the following patients.
A man dehydrated to the point of tachycardia.
A woman dehydrated with dry skin and mucous membranes.
A man in hypovolemic shock.

Answer 14

Tachycardia = 6% fluid loss
Dry = 3% fluid loss
Shock = 9% fluid loss

Question 15

Calculate the total IVF rate for a 60kg man who is dehydrated to the point of tachycardia.

Answer 15

6% deficit.
Calculate real weight - 60kg/.94 = 63.8kg
Calculate deficit - 1L=1kg - patient needs 3.8L of replacement
Maintenance = 1000+500+800=2300
2300+3800=6100
6100/24 hours =254mL/hour

Question 16

When is a fluid bolus appropriate?

Answer 16

When you need to rapidly increase pressure –> sepsis, shock, ect.

Question 17

A patient is having high volumes of fluid lost from his NG tube. You know you have to replace those fluids. What fluid is a good option?

Answer 17

NG tube losses have high Cl levels, so replace with fluid that has chloride. NS and RL are good options

Question 18

What symptoms might you see in a patient whose fluid resuscitation was too vigorous?

Answer 18

Edema, dyspnea, JVD, lung crackles.

Question 19

You ordered IV fluid resuscitation at a rate of 50mL/hour. Someone fucks up and gives 500mL/hour. Your patient is volume overloaded. How do you treat them?

Answer 19

Fluid restriction, diuretics, and lower rate of infusion.

Question 20

What fluids are more commonly used, colloids or crystalloids?

Answer 20

Crystalloids

Question 21

What are crystalloids?

Colloids?

Answer 21

Crystalloids contain electrolytes as the solutes. They can be isotonic, hypertonic, or hypotonic.
Colloids contain large proteins such as albumin as the solutes. These molecules remain intravascular, increased to osmolality and drawing fluid in.

Question 22

Drawbacks to colloids?

Answer 22

Expensive, specific storage requirements, short shelf life

Question 23

When you have to give large volumes of fluid, what is the best fluid to use?

Answer 23

LRs

Question 24

Large volumes of NS can cause?

Answer 24

Hyperchloremic metabolic acidosis, hypernatremia

Question 25

What fluid is administered with blood products?

Answer 25

NS

Question 26

When is 1/2 NS a good choice?

Answer 26

Hypernatremic patients who do not need extra glucose. (diabetics)

Question 27

D5W should not be used in what patients?

Answer 27

Diabetics
or
Hypokalemic (dextrose causes insulin release, insulin stimulates K absorption into cells.)

Question 28

What is the most common postoperative fluid?

Answer 28

D5 1/2NS

Question 29

D5NS is ____(hyper/hypo)tonic. Watch for _____ when giving it.

Answer 29

Hypertonic

Volume overload

Question 30

Your patient is severely hyponatremic. What type of fluid are you going to give, how much?

Answer 30

3% saline in 50-100mL bolus up to 3 times to increase Na.

Then a slow IV infusion at 15-30mL/hour

Question 31

A 50-100mL 3% saline bolus raises serum Na by how much?

Answer 31

2-3mEq

Question 32

Is it very important to raise serum Na slowly to prevent?

Answer 32

Demyelination syndrome (central pontine myelinolysis)

Question 33

Ideal urine output in an adequately hydrated patient?

Answer 33

30-50mL/hour

Question 34

T/F? It is sufficient to start a patient on fluid replacement and check on them the next day.

Answer 34

False- you need to frequently monitor patient and adjust fluid accordingly.