Perioperative Fluid Therapy (Exam IV) COPY Flashcards
What are the primary intracellular and extracellular cations?
Intra: K+
Extra: Na+
Difference between Diffusion and Osmosis:
Diffusion: Moves from higher to lower concentration
Osmosis: Moves from a lower to higher concentration
Osmotic pressure is affected by:
- Temperature
- Number of molecules
- Volume (inversely related)
What is the formula for osmotic pressure?
P = (NRT) / V
P = pressure
N = # of molecules
R = constant
T= temp
V= volume
What is osmolarity?
particles / Liter of solvent
Higher osmolarity = _______ “pulling power”.
higher
What is osmolality?
particles / kg of solvent
What is normal serum osmolality?
280 - 290 mOsm
What three components produce oncotic pressure?
- Albumin (65-75%)
- Globulins
- Fibrinogen
What is the normal daily fluid intake?
- 750 mL from solids
- 350 mL from metabolism
- 1400 mL liquid intake
What is the normal daily fluid output?
- 1000 mL insensible loss
- 100 mL GI loss
- 0.5 - 1 mL/kg/hr UO
Urine output makes up approximately ___% of daily water loss.
60%
This urine output regulator alters renal water excretion in response to plasma tonicity:
ADH
___ is activated with an increase in fluid volume.
ANP
Aldosterone regulates ___ and ___ levels.
Na and K
What sensors does the body have for fluid balance?
- Hypothalamic osmoreceptors
- Low pressure baroreceptors
- High pressure baroreceptors
Where are high pressure baroreceptors located?
Low pressure baroreceptors?
- High pressure → carotid sinus & aorta
- Low pressure → large veins & RA
Where is renin release from?
What does it do?
Renin (released from juxtaglomerular cells) cleaves angiotensinogen to make angiotensin I.
How long does RBC replacement via erythpoiesis take?
4-8 weeks
Where is aldosterone released from?
What does it do?
- Adrenal Cortex
- Na⁺ and H₂O retention
Describe the distribution of crystalloids through the ECF in 20 mins. What about 30 mins?
20 mins: 70% intravascular
30 mins: 50% intravascular
What issues are associated with normal saline use?
- Hemodilution
- ↑ Cl⁻ and K⁺
- Hyperchloremic metabolic acidosis
- ↑AKI & RRT in critical care patients