Fluids Flashcards
Normal Osmolality of a human
280 - 290 MOSM
Normal Saline: osmaolarity and E-lyte concentrations
OSM: 308 mOsmL
Na+: 154 meq
Cl: 154 meq
Ringers lactate: osmaolarity and E-lyte concentrations
OSM: 274 mOsmL
Na+: 130
K+: 4
Cl: 109
Lactate: 28
Plasmalyte : osmaolarity and E-lyte concentrations
OSM: 295 mOsmL
Na+: 140
K+: 5
Cl: 98
Acetate: 27
D5: osmaolarity and E-lyte concentrations
OSM: 252 mOsmL
Glucose: 5%
Albumin 5%: osmaolarity and E-lyte concentrations
OSM: 330 mOsmL
Na+: 145 +/-15
K+: <2.5
Cl: 100
Hetastarch 6%: osmaolarity and E-lyte concentrations
OSM: 310 mOsmL
Na+: 154
Cl: 154
What are the two fluids closest to physiological fluid balances?
Plasmalyte and LR
Drawbacks of fluid recessitating with crystalloids
- Tissue edema (lungs, soft tissues, gut)
- Hypercoagulable (clotting factors are diluted)
Drawback of fluid resusitating with NS
- Dilutes HCT
- Dilutes albumin
- Increases K and Cl
- hyperchloremic metabolic acidosis
- increased risk of AKI and RRT in critical care pts
Lactated ringers is a good choice except in what pathology? why?
Good unless pt has liver failure. Lactate is added as a buffer, but lactate relies on hepatic metabolism
- liver failure causes elevated lactate already - this can build up even more
Effects of colloids
- Increased CO because of increased plasma volume expansion
- Causes hemodilution (decreases plasma viscosity, and inhibits RBC aggregation)
- Uncertain immune, coag, and renal effects
Hydroxyethyl starch effects
- Derived from potato or maiz
- Renal dysfunction
- Can cause coagulopathy
- VWF, Factor VIII, and clot strength become compromised
What are Dextrans primarily used for?
Microvascular surgery
- inhibits factor VIII, VWF, and platelet aggregation
- coats RBC - may interfere with cross matching
Signs of low intravascular volume during anesthesia
- tachycardia
- decreased pulse pressure
- hypotension
- decreased cap. refill
- decreased UOP
- low CVP
Signs of high intravascular volume during anesthesia
- Excess fluid in lungs, bowel, muscle
- decreased gut motility
- reduced tissue oxygenation
- coag changes (could be hypo or hyper)
Classic fluid administration equation for NPO maintanence
4,2,1 rule:
- 1st 10kg = 4mL/Kg/hr
- 2nd 10kg = 2mL/kg/hr
- each 1kg additional = 1mL/kg/hr
How do you replace the fluid deficit?
1/2 the total fluid in the 1st hour of surgery
1/4 in the 2nd hour
1/4 in the 3rd hour
How much blood can a lap sponge, raytech, and 4x4s hold?
- Lap sponge: 100mL
- Raytech: 20mL
- 4x4: 10mL
Parkland burn formula
4mL/kg/%BSA
- 1/2 total volume in 8 hours
- other 1/2 the next 16 hours
We are moving away from the 4,2,1 equation and doing what instead?
Goal directed therapy:
- keep CO at a level that delivers the apropriate amounts of O2 to the tissues
Limitations on SVV mechanics for goal directed fluid therapy
LIMITS
- Low HR/RR (must have normal HR)
- Irregular heart beats (must have normal rhythm)
- Mechanical ventilation (with low Vt) (must have normal vent pattern)
- Increased abd pressure (muct have normal IAP)
- Thorax open (chest must be closed)
- Spontaneous breathing
Types of monitoring for fluid status
- SPV: looks at max systolic apex minus the minimum systolic pressure over the cycle of a mechanical breath (high peak - low peak)
- PP: subtracting high and low
- SVV: area under the curve (variation of SV in 30sec)
- 10-15% difference = normal sono treating with fluid
- use inotropes or vasoconstriction
- > 15% fluid bolus of 250cc
