Apex- fluids, lytes, acid-base Flashcards
(113 cards)
How many L of total body water in a 70kg person
what’s the equation to remember
42L
60/40/20 (15/5)
60% TBW = 42L
40% ICV = 28L (40% x 70kg = 28L)
20% ECV= 14L
15% of ECV is intersistal fluid - 11L
5% of ECV is plasma - 3L
Major intracellular (3) vs extracellular (4) ions
intracellular = K, Mag, Phosphate
extracellular = Na, CA, Cl, HCO3-
What populations have the highest TBW (1)
vs lowest TBW (3)
Highest = neonates
Lowest = olds, fats, females
Think low muscle mass = less body water = less total body water
What forms a protective layer on the interior wall of the blood vessel
what happens when this is disrupted and what could distrupt it
glycocalyx
disruption > capillary leak (sepsis)
What does the lymphatic system do?
It pretty much filters out proteins, fluids, bacteria, and debris that have entered the intersistium (fluid filled space between structures such as cell membranes)
takes the extra fluid thats lost in the capillary exchange going on in the tissue and mops it up and returns it to the lymphatic ducts
-returns about 3L/day of fblood fluid per day to your ciruclatory system; without it functioning well, all that fluid is going to be outside the vasculature and in the interestial spaces
>swelling, hypotension
How does staph from your skin get into your blood stream from a scrape - outside of direct exposure to vessels
tissue is full of intersistal fluid that drains into your lymphatics which then drain to your heart
What is lymph?
how does it get cleared out from the tissues?
it’s essentally plamsa that leaks out of the capillaries
-see your circulatory system is a pressurized system, so everytime blood circulates through the capillaries, the capillaries have small holes in them that plasma (ECF) will leak out of the vessels and into the surrounding tissues
-small holes allows for larger molecules to get into the cells that are too big to diffuse through the walls of the capillaries like o2 and co2 can (like nutrients such as glucose from the RBCs and other waste products like nitrogen to get back into the vessels)
there are lymph vessels that clear it from the tissues
-build up of lymph fluid in the tissues, compresses the lymphatic vessels which have pressurized valves that open once lymph reaches a certain presssure in the tissues, then gets forced into the lymphatic vessels ; then when the pressure accumulates inside, it forces the valves shut and it cant escape back out
jobs of lymphatic system
- clears lymph from tissues and gets it back into the circulatory system via the veins
- immunity- lymph nodes serve as check points throughout the lymphatic system that will filter out any bacteria that may be in the lymph so it’s not deposited into your bloodstream
- transfers fat - carbs and proteins can leave the intestines and enter the capillaries; but fat cannot, the lymph picks it up and drops it off into the blood stream
your lymphnodes get big as an early sign of infection because once it has bacteria , it recruits RBCs to those lymph nodes to help destroy the bacteria
which pushes vs pulls fluid: onctoic vs hydrostatic
hydrostatic PUSHES fluid out
oncotic PULLS fluid in
The intracellular compartment is what % plasma and what % blood?
what is hematocrit?
what increases/decreases it?
60% plasma , 40% blood
the fraction of blood volume that is occupied by erythrocytes
increased hct = increased # of RBCs (chronic hypoxia) or decreased plasma volume (dehydration)
decreased hct = decreased # RBCs (anemia) or increased plasma volume (hemodilution)
Where is the thoracic duct?
at the juncture of the internal jugular vein and subclavian veins
*left = larger (risk of chylothorax during left IJ placement)
thoracic duct is where lymph is returned to venous circulation
What is fluid that accumulates in a potential space called?
an effusion
Label
Osmolarity vs Osmolality
OsmolaRity = # of osmoles per liteR of a solution
Osmolality- # of osmoles per kg of a solution
What is osmosis
the movement of water across a semipermeable membrane
not solute
T/F- osmotic pressure is a function of molecular weights
false - it’s a function of the number of osmotically active particles in a solution
Calculate the plasma osmolarity:
Sodium= 150 mEq/L
Glucose = 108g/dL
BUN= 14mg/dL
311 mOsm/L
(NA+ x 2) + (Glucose/18) + (BUN/2.8)
so youre adding everything
just remember
NA x 2
Glucose / 18
BUN / 2.8
*from the image you can see sodium is most important determinant and that hyperglycemia nad uremia can also increase the plasma os
Normal Plasma osmolarity
280-290 mOsm/L
What is the most important determinant of plasama osmolarity
Sodium
3 conditions that increase plasma osmolarity
hypernatremia, hyperglycemia, uremia
Rank the tonicity for each fluid, 1 being highest and 4 being lowest:
Albumin 5%
D5 0.45%
D5W
NaCl 3%
- NaCl3%
- D5 0.45%NS
- Albumin 5%
- D5W
Hypo (2) vs Iso (3) vs hypertonic solutions (4)
Hypotonic - lower osmolarity than plasma/cells (cells swell)
→ D5W & NaCl 0.45%
Isotonic- similar osmolarity to plasma/cells (no change)
→ 0.9% NaCl, LR, Plasmalyte
Hypertonic- higher os than plasma/cells
→ 3%NaCl, D5NS, D51/2NS, D5LR
so pretty much the only hypotonic ones are D5W and 0.45%NaCl by themselves
-add them together and its hypertonic
T/F: Albumin 5%, Voluven 6%, and Hespan 6% are all isotonic solutions
True
T/F: Dextran 10% is considered hypertonic
True