Card Set Information
BC Boston College CRNA fluids lecture
BC Boston College CRNA fluids lecture
What is the total body water volume?
40 - 42 L
What is the volume of the intracellular fluid?
28-30 L or about 64%
What is the volume of the Extra cellular fluid?
14 L or about 33%
What percentage of our weight is fluid?
Volume of plasma?
Volume of interstitial fluid?
What stuff is in the plasma compartment?
plasma and cells
What is the non-cellular component of blood?
What is the difference between the composition of plasma and interstitial fluid?
concentration of proteins
Where are proteins confined?
What creates the osmotic gradient in plasma?
How much greater is the osmolarity of plasma than the interstitial fluid?
20 mmHg greater, this is what keeps fluid in the intravascular space
What is the lyte composition of plasma in mEq/L?
What is the lyte composition of the interstitial fluid in mEq/L?
What is the lyte composition of the intracellular fluid in mEq/L?
What is the donnan effect?
describes the effect that lytes (not protein) have on the overall oncotic pressure. Overall it raises the pressure.
What is the avg colloid pressure?
How much of the 28 mmHg in colloid oncotic pressure is due to plasma proteins?
How much of the 28 mmHg in colloid oncotic pressure is due to the lytes?
Why the cations that make up the donnan effect stay in the plasma?
They are electrically attracted to the - charged Proteins.
Are lyte concentrations similar or not in between the plasma and the interstitial fluids?
Na+, Cl-, Ca++ and HCO3 are found more prominently in the extracellular or intracellular?
Where are the greatest concentrations of Ca++, Mg++, PO4-, and organic acid ions (lactate, pyruvate)?
Do the cells or the plasma contain more protein?
What is the regulating organ of the composition of extracellular fluid?
What nonelectrolytes are found in the plasma?
glucose - 100 mg/dl
urea - 15mg/dl
lactic acid - 10mg/dl
uric acid - 3mg/dl
creatinine - 1.5 mg/dl
bilirubin - 0.5 mg/dl
bile salts - trace
About how much water/day does oxidation of food particles release?
About how much water do we lose/day through generation of urine?
What volume do we usually sweat/day? (not including presentations Brenna) ;)
100 ml, can increase to 5L with heavy exercise
What is Sue going to do while her 70 year old cousin runs the Boston marathon?
What is the total insensible fluid loss?
How much fluid do we lose/day in the GI tract?
Do the kidney help to maintain our water balance and if so by what?
yes, the action of ADH ( where is it secreted?)
Where are the osmoreceptors located that measure the osmolarity of our blood?
Can a small change of 3% stimulate ADH secretion?
How does ADH allow for more water reabsorbtion?
Signals the insertion of aquaporins.
What are three hormones (mentioned in the fluids lecture) that controll the balance of water?
What is osmolarity?
# of osmotically active particles per L of solvent
What is osmolality?
# of osmotically active particles/ Kg solvent
How can we approximate osmolarity?
= 2[Na+] + [Glucose]/18 + [ BUN ]/2.8
What is tonicity?
Term that compares osmotic pressure of IVF's to that of plasma
What is the normal osmolality of the blood?
278 - 300
When we administer an isotonic fluid what occurs in relation to the fluid compartments?
ECF increases but ICF stays the same
No change in osmolarity of the compartments
When we administer a hypotonic fluid what occurs in relation to the fluid compartments?
Some of the ECF fluid will go to the ICF, but ECF volume will be expanded as well
The ICF receives fluid from the ECF
: a greater increase than the ECF is experienced
Both ICF and ECF osmolarity decrease
When we administer an hypertonic fluid what occurs in relation to the fluid compartments?
Water leaves the ICF and goes to the ECF
In the ECF the volume is enlarged by both the influx of ICF, and the administration of the fluid.
Both compartments increase in osmolarity
What is an Isotonic fluid's tonicity?
What is a hyptonic fluid's tonicity?
What is a hypertonic fluid's tonicity?
What are isotonic fluid used for?
Expanding the Extra cellular fluid compartment. Very little will move into the cell
How much (in percentage) of an Isotonic fluid moves into the interstitium?
How much (in percentage) of an isotonic fluid stays in the plasma?
Why does so much of an Iso IVF move to the interstitium?
The interstitium is about three times the volume of the plasma
What is the tonicity of D5W?
Isotonic initially but after the dextrose is metabolized all that is left is the free water
What is the effect of the free water left behind an administration of of D5W?
The cells will swell until equilibration occurs.
What are the relative ratio's of ICF and ECF?
When we give a liter of D%W, how much in volume goes to ICF, interstitial, and plasma?
ICF 670 ml's or 2/3
Why do we give dextrose in solutions?
to provide calories, this:
-spares the breakdown of proteins
-and prevent ketosis from oxidation of fat
-can help to move K+ from ECF to ICF
What is the maximum rate of dextrose that can be given?
0.5 gram/kg/hr rates exceeding this will precipitate glycosuria
or 700 ml/hr for the average 70 kg male
Why do we use LR?
they are near physiologic in their electrolyte concentration
Isotonic and surgical losses are isotonic
Why is lactate added to LR?
to buffer the solution: It is metabolized to HCO3
Giving too much NS can result in what?
hyperchloremic metabolic acidosis
What acid base imbalance can metabolized lactate in LR precipitate?
metabolic alkalosis with large infusions
If the patient has renal failure or hyperkalemia should you use LR?
LR has K+ so we would need to be cautious in these pt's
If we are doing a case where large volumes of crystaloid need to be given, how might we choose the fluids?
we may need to alternate bags of LR and NS.
If our 70 kg pt loses 2L during surgery and his total predicted blood volume is 5L, what is his percent blood loss?
How much crystaloid would we give our 70 kg pt with 5L predicted blood volume who lost 2L?
What is the blood loss replacement equation?
How do we figure normal plasma volume?
Volume of cells in plasma=TPV*hct%
With isotonic crystaloids for every 1ml of blood loss how much fluid are we going to replace?
3mls for every 1 of blood
What patients are at risk for hypoglycemia?
Infants and pt's who are on insulin
Osmotic diuresis can occur when we?
administer too much glucose in our fluid in surgery
Why would we want to avoid Glycosuria?
it would have the opposite effect of hydration
What are some cases that we would need to replace specific lytes as opposed to general crystaloids?
fluid loss from wounds, gastric suctioning, ascities
When making a fluid plan what types of losses will we replace?
3rd spacing/tissue trauma
What it the 4-2-1 rule?
When figuring maintenance fluids we base it on Kg's:
-4 ml/kg for the first 10 kg +
-2 ml/kg for the second 10 kg +
-1 ml/kg for the rest of the kg's Equals total hourly dose
How do we figure NPO deficit?
maintenance dose X#of hours NPO
How do we figure replacement for tissue trauma:
4-6 ml/kg/hr minimal
6-8 ml/kg/hr moderate
8-10 ml/kg/hr extreme
What is the general rule when replacing NPO deficit?
half of total deficit in first hour
quarter of total deficit in second hour
quarter of total deficit in third hour
When replacing blood loss with cells what is the ratio?
What do they estimate fluid loss for a pt that has taken bowel prep?
additional 2 liters
When we adminster anesthesia what happens to the overal volume of the vasculature?
Does ADH and aldosterone secretion decrease or increase with surgery?
What vasoactive hormone does mechanical ventilation effect and how does it effect (increase or decrease).
ANP and decreases
What does an decrease in ANP do to the kidneys?
makes them conserve sodium
How much Na+ and K+ does a healthy person require each day?
Na+ 70 mEq/day
K+ 40 mEq/day
How much albumin is in a container of albumin?
12.5 grams regardless of weather it is the:
5% in 250 ml, isotonic to plasma, has Na+ and little K+
25% on 50 ml
How much does 25% albumin expand the blood vilume?
4-5 X its own volume so, 200-250 ml's but can be unpredictable.
Hespan has been associated with?
and a decrease in factor IIX
decrease in vonwilderbrands factor
decreased platelet function
What is the proposed reason by which the antiplatelet activity of hespan is induced?
coats the surface of the platelets which causes the clotting factors to precipitate so they aren't available for clotting
What is Dextran 70?
water soluble glucose molecule, 70 refers to the molecular weight
What is dextran 40?
low molecular weight dextran
How long will dextran 70 stay in the plasma?
Does dextran 70 interfere with coagulation?
What are the two main actions of dextran?
plasma expansion and anticoagulation
Of Dextran or hespan which one is more likely to precipitate in an anaphylactic reaction?
Dextran has a low, but still greater chance to precipitate allergies than any of the other colloids in use.
What is the antibody that causes the reaction to dextran?
circulating dextran igG antibodies that most people have
about 1 in 3000 administrations will have a reaction
What is most commonly associated with administration of > 1500 ml of dextran?
increased bleeding times-decreased platelet adhesion
impaired coagulation may not be apparent until 6-9 hrs following dosing
In what situation would dextran gain access to our pt's without our administration?
It is sometimes used as irrigation in hysteroscopies.
What fluids, that we don't control, might cause cerebral edema or noncardiogenic pulmonary edema?
Irrigation used in certain procedures
In what situations would you use a colloid?
To preferentially expand plasma
In what specific situation would crystalloid be preferred?
What is the most commonly used colloid?
Greater than 20ml/kg/day of hespan has been associated with what?
What are the advantages of colloid solutions?
Smaller infused volume
Prolonged ↑ PV
Less peripheral edema
What are the disadvantages of Colloid?
Coagulopathy (dextran > Hespan)
Pulmonary edema (capillary leak states)
Osmotic diuresis (LMWD)
> Duration of excessive volume expansion
What are the advantages of crystalloids?
Greater urine flow
Interstitial fluid replacement
What are the disadvantages of crystalloids?
Transient ↑ intravasc volume
Transient hemodynamic improvement
Peripheral edema (protein dilution)
Pulmonary edema (protein dilution plus high PCWP)