Flashcards in Fluid Management Deck (74):
Between the ISF and the ICF, ____ is the main determinant of extracellular osmotic pressure
Between the ISF and the ICF, ____ is the main determinant of intracellular osmotic pressure
What is hematocrit?
It is also known as the packed cell value (PVC). It is measured by dividing the volume of RBCs in a centrifuged blood sample by the total volume of the sample.
What are some ways that we can assess fluid volume status?
Urine spec gav
Why are maintenance fluids given?
To replace insensible losses (from resp tract, GI tract, urine, feces, perspiration, etc)
What is the formula for maintenance fluids?
4cc/kg for the 1st 10kg
2cc/kg for the 2nd 10kg
1cc/kg for each additional kg
How to calculate fluid deficit
(Maintenance rate) x (number of hours NPO)
But remember to look at pt history! May have been NPO, but was probs receiving IV fluids if pre-admitted to the hospital (no deficit).
Also, if hypovolemic at baseline (ex- on ACE inhibitors, have been vomiting, have NG to suction, chest tube, etc.), they will have a larger than calculated fluid deficit.
Fluid should be replaced to restore HR, BP, and filling pressures prior to induction****
Normal UO is also desirable
Replacement strategy for fluid deficit
Replace over 3 hours
Replace 1/2 deficit in 1st hour
Replace 1/4 in the 2nd hour
Replace final 1/4 in the third hour
When should we begin fluid deficit replacement?
ASAP! Start fluids in the holding area. Want to make sure they aren't totally dry on induction.
A soaked 4x4 holds _____cc of blood
A soaked lap sponge (lap tape) holds ___cc of blood
100-150cc (soaked an dripping)
We tend to (over/under)estimate the amount of blood loss
Calculations for estimated blood volume (EBV)
Preemies = 95mL/kg
Term = 85mL/kg
Infants = 80mL/kg
Children = 70mL/kg
Men = 75mL/kg
Women = 65mL/kg
[EBV (Hct - allowable Hct)] / Hct
Remember that this is not the trigger for transfusion. Always look at your pt's condition (HR, BP, Sats, etc). You may need to transfuse earlier than expected.
Fluid loss due to third spacing may be caused by
Burns, trauma, infection.
Loss of intravascular volume due to massive redistribution of fluids.
Surgeries and their expected evaporative/3rd space loss
- Eye cases, lap chole, hernia, knee scope
- Open chole, appendectomy
- Bowel surgery, total hip replacement (THR)
- Gun shot, MVC
D5W has an osmolarity of
253 (these are called maintenance fluids)
Isotonic solutions have an osmolarity of
300 (these are called replacement fluids)
Examples of isotonic solutions
NS and LR
Examples of hypertonic solutions and their osmolarities
Used for hyponatremia or shock
3% NS (1026)
Advantages and disadvantages of crystalloids
Easily warmed and stored, non-allergenic
No O2 carrying or coagulation capacity, limited intravascular life (will be peed out by patient)
LR provides ____cc of free water per liter of fluid
This tends to lower Na+
This is the most physiologic crystalloid solution (most similar to ECF)
This fluid should not be give with blood
LR --> the calcium can cause the blood to clot
Electrolyte concentrations in LR
Na (130 mEq/--> results in hyponatremia
K (4 mEq/L) --> avoid in hemodialysis pts!!
Ca (2.7 mEq/L)
Cl (110 mEq/L)
Lactate (27 mEq/L) --> will be converted to bicarbonate
This can result from large volumes of .9%NS
High chloride-content hyperchloremic acidosis
This is the preferred solution for diluting PRBCs
D5W can cause these adverse effects
Free water intoxication and hyponatremia
What use does D5W have?
Really only used for diabetics who need just a little more glucose, and is used as a carrier for regular insulin
Half-life of colloid solutions
16 hours (but may be as short as 2-3 hours)
Benefits of colloids
Easy to store, inexpensive, safer to give than blood (no viral transmission, etc.)
Albumin is available in these concentrations
5% or 25%
We use 5% in the OR
What is IV albumin?
It's obtained from fractionated human plasma, however, does not contain antibodies or coagulation factors
What is dextran made of?
Water-soluble glucose polymers that are enzymatically degraded to glucose.
Two types of dextran and what they're used for
Dextran 40 - used on the pump for thrombosis prevention
Dextran 70 - used for volume expansion***
SE of dextran
Anaphylaxis (1 : 3,000 pts)
Platelet inhibition (causes increased bleeding. Max dose of 20mL/kg in 24 hours)
Noncardiac pulmonary edema (from volume expansion)
Interference with crossmatching
Benefits of hetastarch
It's as effective as albumin for volume expansion, but less expensive.
How is hetastarch stored and excreted within the body
Stored within the reticuloendothelial system (phagocytic system) and excreted via the kidneys.
Hetastarch and dextran can both cause bleeding problems, but differ in how they do it. What is the MOA for this in each and what is the max dose for each?
Dextran --> plt inhibition
Hetastarch --> dilutional thrombocytopenis
Max dose for both is 20mL/kg.
In renal failure, which should dextran or hetastarch be chosen?
Dextran** This is enzymatically degraded into glucose.
Hetastarch, however, is exreted via the kidneys.
Intravascular half-life for crystalloids
(colloids have half-life of 2-16 hours)
This type of fluid is preferred in hypoproteinemia
What is the only reason to transfuse blood?
To increase O2 carrying capacity
Transfusions are rarely indicated if Hgb > ____ and are almost always indicated if Hgb < ____
Transfusion between this range is based on the pt's risk for complications and inadequate oxygenation
What is cell saver?
Recovering blood lost during surgery and re-infusing it into the patient. It is a major form of autotransfusion.
T or F? Indications for transfusion are more liberal for autologous blood vs. blood bank blood
Risks of blood product administration
Hep B (1 : 269,000)
Hep C (1 : 600,000)
HIV (1 : 1,780,000)
Platelets (apheresis ) - 1 : 50,000
Platelets (in whole blood) 1 : 33,000
Platelets (untested) 1 : 2,500-13,400
1 Unit of PRBCs will increase Hgb by
What is the Hct of PRBCs
What are PRBCs reconstituted with?
5% dextrose in .9% NS
5% dextrose in .4% NS
Normosol-R (pH of 7.4)
Citrate toxicity and blood transfusions
Citrate is the anticoagulant used in blood products. Massive PRBC transfusion can cause citrate to accumulate. Citrate binds to calcium and magnesium, causing hypocalcemia and hypomagnesemia.
What is autologous blood transfusion?
Autologous blood transfusion is the collection of blood from a single patient and retransfusion back to the same patient when required. The pt is able to donate a unit of blood (450cc) of blood every few days in the weeks leading up to surgery (up to 4 units). The last collection should take place at least 48–72 h before surgery to allow for equilibration of blood volume.
Complications of autologous transfusion
Anemia (from collections) and resultant myocardial ischemia
Administration of the wrong unit (1 : 100,000)
Need for more frequent transfusion
Febrile and allergic reaction
Uses for plt transfusion
Having shitty platelets
One unit of plts will increase plt count by
7,000 - 10,000
Volume given when plts are transfused
Contamination risk with plts
Bacterial contamination 1 : 2,000
Plt related sepsis 1: 12,000 (be wary of this if pt spikes fever within 6 hours of administration)
Volume of FFP given
Does FFP have to be ABO compatible?
What is contained in FFP?
Clotting factors and plasma proteins. No cells!!
Uses for FFP
- Emergent reversal of warfarin
- To correct known coag factor deficiencies
- To correct microvascular bleeding in the presence of an increased PT or PTT
- To correct microvascular bleeding in someone who has been transfused with more than one blood volume when PT and PTT can't be obtained in a timely fashion
Each unit of FFP increases each clotting factor by ___%
What is FFP not used for?
NOT used to increase volume or albumin concentration
How is cryoprecipitate made and what does it contain?
It's derived from the precipitate remaining after FFP is thawed.
- Factor VIII and XIII
Is cryo ABO compatible?
What is cryo used for?
von Willenbrand's disease
How should cryo be given?
Rapidly and through a filter (200mL/hr).
Infusion must be complete within 6 hours.
Are plts given through a warmer or filter?
This colloid comes in two forms: 40 and 70
Which is more likely to cause pulmonary edema, crystalloids or colloids?
Are crystalloids just as effective as colloids in restoring intravascular volume as long as enough is given?
Which supports UO better, crystalloids or colloids?
More tissue edema occurs with (crystalloids/colloids)