Exam 4 (Fluid therapy) Flashcards
What are the parts (5) of the transcellular compartment?
- GI tract
- Urine
- CSF
- Joint fluid
- Aqueous humor
What are the parts of the interstitial compartment?
- Lymphatics & protein- poor fluid around cells
What is the speed solutes move at?
Proportional to distance squared
What is osmosis?
- Semipermeable membrane separate pure water from water with solute
- Diffuses from low to high concentration
What is osmotic pressure?
Pressure that resists the movement of water through osmosis
What is the formula for osmotic pressure?
P= (NRT) / V
- N= # of molecules
- R= constant
- T= temperature
- V= volume
What is osmolarity?
Number of active particles per Liter of solvent
What is osmolality?
Number of active particles per Kilogram of Solvent
What is the normal osmolality?
280 - 290 mosm
What does a higher osmolarity refer to?
Higher “Pulling power”
What makes up oncotic pressure?
- Albumin
- Globulins
- Fibrinogen
Most of our daily average fluid output comes from?
Insensible loss (sweat, tears, breath vapor)
What does Aldosterone regulate?
- Sodium & Potassium levels
- If Na⁺ & fluid drops the aldosterone is released causing Na⁺ & H₂O retention
What do the hypothalamic osmoreceptors do?
Figure out osmolality vs osmolarity
What are the acute compensators (5) for volume loss?
- venoconstriction
- Mobilization of venous reservoir
- Autotransfusion from ISF to plasma
- Reduced urine production
- Maintenance of cardiac output
What does Renin do/ where does it come from?
- Cleaves Angiotensinogen to make Angiotensin 1
- Released from Juxtaglomerular cells
How long does it take to restore an RBC count?
4 - 8 weeks
How long does it take the RAA Axis to restore volume?
12 - 72 hours
Aldosterone is released from the?
Adrenal cortex
Which IV fluids have the highest & lowest osmolarity?
- Highest: Albumin
- Lowest: D5
What is the most “balanced” crystalloid?
LR
What are the indications for crystalloids?
- Replacement of free water & electrolytes
- Volume expansion
What is the distribution of volume of crystalloids over time?
- After 20 mins 70% is intravascular
- After 30 mins 50% is intravascular
What are the possible side effects of crystalloids?
- tissue edema
- hypercoagulability
What are downsides of normal saline?
- Increases Cl⁻ & K⁺ concentrations
- Late onset of diuresis
- causes hyperchloremic metabolic acidosis
- Increases AKI & RRT in critical care Pts
What are the uses for 3% saline?
- Treats hypoosmolar hyponatremia
- Treats increased ICP
Who should not receive LR?
Liver impaired Pts
Which crystalloid excretes excess water faster? How?
- LR > NS
- Supresses ADH secretion
Colloids do what to RBC’s?
Inhibit RBC aggregation
How much hydroxyethyl starch is intravascular after 90 mins?
70 - 80%
What are the side effects of hydroxyethyl starch?
- Renal dysfunction
- Coagulopathy (vWF, Factor VIII & clot strength)
When is Dextran-40 use appropriate?
- How does it work?
- For microvascular surgeries
- Inhibits Factor VIII, vWF & Plt aggregation
What does Dextran possibly interfere with?
- Cross-matching due to it coating the RBC’s
What are the signs of low intravascular volume?
- tachycardia
- Decreased pulse pressure
- Hypotension
- Decreased capillary refill
How much volume must be lost to show S/S of volume depletion?
25%
How do anesthetics relate to urine output?
Anesthetics release stress hormones, which leads to increased volume retention. Therefore decreased urine output
What can excessive crystalloids or colloids lead to?
- Edema (lungs, bowel, muscle
- Increased capillary hydrostatic pressure
- Reduced tissue oxygenation
- poor wound healing
- hypo/hyper coagulation
What is the classic fluid therapy used for?
- NPO deficit
- Ongoing maintenance
- Anticipated surgical loss
What is the basic formula for NPO deficit?
- 1st 10 Kg= 4 mL/kg/hr
- 2nd 10 Kg= 2 mL/kg/hr
- Each 1 Kg > 20 Kg= 1 mL/kg/hr
How is a volume deficit replaced?
- 1/2 of the volume in the 1st hour of Sx
- 1/4 of the volume in the 2nd hour of Sx
- 1/4 of the volume in the 3rd hour of Sx
How much blood can a saturated lap sponge hold?
100mL
How much blood can a raytech hold?
20mL
How much blood does a saturated 4x4 hold?
10mL
What is the traditional method of replacing preoperative bleeding?
3 : 1 with crystalloids
A septic Pt with a 40 degree Celcius fever, has how much deficit?
30%
A bowel Prep results in how much volume deficit?
~ 2,000 mL
How are the evaporative/redistribution losses calculated?
- Minimal: 0 - 2 mL/kg/hr
- Moderate: 2 - 4 mL/kg/hr
- Severe: 4 - 8 mL/kg/hr
When is the Parkland formula used?
Only if 20% of TBSA has 2nd &/or 3rd degree burns
What fluid is used in burns?
- At what rate?
- LR
- 4 mL/kg/% BSA burn (1/2 over first 8hrs & rest over 16hrs)
What body surfaces count as 4.5%?
- Each arm
- Front of the head (face)
- Rear of the head
What does SPV measure/look at?
Lowest systolic peak vs highest systolic peak
What does SVV look at?
Area under the curve
What is a normal SVV?
10 - 15%
What are the Limits to SVV monitoring?
- Low HR/RR
- Irregular heart beats
- Mechanical ventilation w/ low Vt
- Increased abdominal pressure
- Thorax open
- Spontaneous breathing
