Perioperative Fluid Therapy (Exam IV)

Question 1

What is the formula for osmotic pressure?

Answer 1

P = (NRT) / V

P = pressure
N = # of molecules
R = constant
T= temp
V= volume

Question 2

What is osmolarity?

Answer 2

particles / Liter of solvent

Question 3

Higher osmolarity = _______ “pulling power”.

Answer 3

higher

Question 4

What is osmolality?

Answer 4

particles / kg of solvent

Question 5

What is normal serum osmolality?

Answer 5

280 - 290 mOsm

Question 6

What three components produce oncotic pressure?

Answer 6

1. Albumin
2. Globulins
3. Fibrinogen

Question 7

What is the normal daily fluid intake?

Answer 7

• 750 mL from solids
• 350 mL from metabolism
• 1400 mL liquid intake

Question 8

What is the normal daily fluid output?

Answer 8

• 1000 mL insensible loss
• 100 mL GI loss
• 0.5 - 1 mL/kg/hr UO

Question 9

Urine output makes up approximately ___% of daily water loss.

Answer 9

60%

Question 10

What sensors does the body have for fluid balance?

Answer 10

• Hypothalamic osmoreceptors
• Low pressure baroreceptors
• High pressure baroreceptors

Question 11

Where are high pressure baroreceptors located?
Low pressure baroreceptors?

Answer 11

• High pressure → carotid sinus & aorta
• Low pressure → large veins & RA

Question 12

Where is renin release from?
What does it do?

Answer 12

Renin (released from juxtaglomerular cells) cleaves angiotensinogen to make angiotensin I.

Question 13

How long does RBC replacement via erythpoiesis take?

Answer 13

4-8 weeks

Question 14

Where is aldosterone released from?
What does it do?

Answer 14

• Adrenal Cortex
• Na⁺ and H₂O retention

Question 15

What issues are associated with normal saline use?

Answer 15

• Hemodilution
• ↑ Cl⁻ and K⁺
• Hyperchloremic metabolic acidosis
• ↑AKI & RRT in critical care patients

Question 16

How does lactated ringers osmolarity compare to that of NS?

Answer 16

LR osmolarity is lower than NS.

Question 17

Why is lactate added to LR?

Answer 17

Buffering capacity

Question 18

___ will excrete excess water faster than NS.

Answer 18

LR

Suppresses ADH secretion, allows for diuresis.

Question 19

Lactate formation relies on what?

Answer 19

Hepatic metabolism

Question 21

Colloid particles are separated via a centrifuge. T/F?

Answer 21

False. Colloid particles cannot be separated from crystalloid solution (via centrifuge or filtration).

Question 21

What are the hemodilutionary effects of colloid administration?

Answer 21

• ↓ plasma viscosity
• ↓ RBC aggregation

Question 22

What fluid “class” can have adverse effects on the immune, coagulation, and renal systems?

Answer 22

Colloids

Question 23

What is Hetastarch?
What is it derived from?

Answer 23

Modified natural polymers of amylopectin derived potato or corn/maize.

Question 24

How much of intravascular volume expansion from hetastarch is still present in the system 90 minutes later?

Answer 24

70-80%

Question 25

What are side effects of hetastarch?

Answer 25

- Coagulopathy - Renal dysfunction

Question 26

What is Dextran?

Answer 26

Highly branched polysaccharide

Question 27

What type of surgery is dextran useful for? Why?

Answer 27

Microvascular surgery due to inhibition of clotting cascade.

Question 28

What can dextran interfere with? (besides the clotting cascade)

Answer 28

Blood crossmatching due to coating of RBCs

Question 29

What are signs/symptoms of high intravascular volume?

Answer 29

- ↑ capillary hydrostatic pressure - Edema - ↓ tissue O₂ - Poor wound healing - Dysfunctional coagulation

Question 30

What are standards for NPO status?

Answer 30

Question 31

What is the classic formula for NPO/maintenance fluid replacement? **4-2-1 Rule**

Answer 31

1st 10kg = 4 mL/kg/hr → 40mL/hr 2ⁿᵈ 10kg = 2 mL/kg/hr → 20mL/hr Each 1kg over 20kg = 1mL/kg/hr

Question 32

What would the maintenance fluid rate (4-2-1 rule) be for a 110kg patient?

Answer 32

40 mL + 20 mL + (90 x 1mL/kg/hr) → **150 mL/hr**

Question 33

What would the maintenance fluid rate be for a 18kg toddler?

Answer 33

1st 10kg → 40 mL 2ⁿᵈ 8kg → 16 mL = **56 mL/hr**

Question 34

How is fluid deficit replaced in a surgery?

Answer 34

½ calculated volume in 1st hour ¼ volume in 2ⁿᵈ hour ¼ volume in the 3rd hour

Question 35

How is fluid deficit calculated?

Answer 35

hours NPO x 4-2-1 maintenance rate

Question 36

How is hourly intraoperative volume replacement calculated?

Answer 36

Deficit + Maintenance + EBL

Question 37

How much blood do lap sponges hold?

Answer 37

100 mL

Question 38

How much blood do Raytech's hold?

Answer 38

20 mL

Question 39

How much blood does a 4x4 hold?

Answer 39

10mL

Question 40

What would the replacement volume rate be for a surgical case that exhibits minimal (robotic, toe pin, cataract, etc.) evaporative/redistributive volume loss?

Answer 40

0-2 mL/kg/hr

Question 41

What would the replacement volume rate be for a surgical case that exhibits moderate evaporative/redistributive volume loss?

Answer 41

2-4 mL/kg/hr

Question 42

What would the replacement volume rate be for a surgical case that exhibits severe evaporative/redistributive volume loss?

Answer 42

4-8 mL/kg/hr

Question 43

How is the Parkland burn resuscitation formula calculated?

Answer 43

4 mL/kg/ %BSA burned

Question 44

How is the volume calculated via the parkland formula given?

Answer 44

½ in the 1st 8 hours ½ in the next 16 hours

Question 45

What are the general characteristics of goal directed therapy?

Answer 45

- Volume administration based on hemodynamics - 1-3 mL/kg/hr crystalloid - 250cc fluid challenges for ↓SV - 1:1 colloids for blood loss

Question 46

What is normal SVV? (PPV, SPV as well)

Answer 46

10 - 15 %

Question 47

What are the limits to assessment of volume via arterial waveform monitoring?

Answer 47

**L**ow HR and/or RR **I**rregular HR **M**echanical ventilation **I**ncreased abdominal pressure **T**horax open **S**pontaneous ventilation