E4- Perioperative Fluid Mgmt Flashcards
What percentage of total body weight is water?
Who has lower TBW %?
- 60%
- Elderly + Obese patients = lower percent of TBW
Elderly + Obese patients = lower percent of TBW
Pediatrics = HIGHER TBW
What are the two main compartments fluid compartments?
- ICF = 2/3 TBW
- ECF = 1/3 TBW
What are 3 different compartments of the ECF?
- Interstitial = lymphatics + protein-poor fluid around the cell.
- Intravascular = plasma volume
- Transcellular = GI Tract, Urine, CSF, Joint fluid, aqueous humor.
What is diffusion?
- Solute particles moving or filling solvent volume
- High to Low concentration
- Speed is proportional to the distance square
- Can occur across permeable membranes
- Can relate to electrical gradients
What are examples of the type of solutes that are in our body?
- Glucose
- Protein (Albumin)
- Electrolytes
What is the primary extracellular cation?
- Sodium (Na+)
What is the primary intracellular cation?
- Potassium (K+)
What is osmosis?
- Semipermeable membrane separates pure water from water with solute
- Osmosis is just movement of WATER
- Diffuses from low to high solute concentration
What is osmotic pressure?
- Pressure that resists the movement of water through osmosis
What is osmotic pressure affected by?
Formula?
- Directly related = temp + # molecules
- Indirectly related = Volume
- P = nRT/V
PV = nRT
What is osmolarity?
- Number of osmotically active particles per L of solvent
- Higher osmolarity = higher “pulling power”
Patient A has serum glucose of 600mg/dl
Patient B has serum glucose of 250mg/dl
Who has higher osmolarity?
- Patient A
What is osmolality?
- Number of osmotically active particles per Kg of solvent
What is normal osmolality?
- 280-290 mOsm
What is oncotic pressure?
- The component of total osmotic pressure due to colloids
List examples of colloids
- Albumin
- Globulins
- Fibrinogen
What percentage of oncotic pressure is due to albumin?
- 65-75%
What makes up our daily intake?
Normal Daily Balance
- Solids = 750 mL
- Liquids = 1400 mL
- Metabolism = 350 mL
What makes up our daily output?
Normal Daily Balance
- Insensible Loss = 1000 mL
- GI loss = 100 mL
- Urine output = 0.5-1 mL/kg/hr
Urine secretion accounts for ____-% of daily water loss.
- 60%
What 3 hormones regulate urine output?
- ADH
- ANP
- Aldosterone
How does ADH regulate urine output?
- Renal H2O excretion in response to plasma tonicity
How does ANP regulate urine output?
- ANP is activated by ↑ fluid volume
- ↑ Atrial Stretch = ↑ Renal Excretion
How does Aldosterone regulate urine output?
- Regulates Na + K levels
- Aldosterone is released if sodium + fluid volume decreases»_space; Na + H2O conservation
What are the 3 sensors for fluid balance?
Locations?
- Hypothalamic osmoreceptors
- Low-pressure baroreceptors = large veins and RA
- High-pressure baroreceptors = carotid sinus and aortic arch
What are 2 trigger for fluid balance?
- Increased thirst
- Increase ADH
What are the 5 compensatory mechanisms for acute disturbances in circulating volume?
When do they occur?
- Venoconstriction
- Mobilization of venous reservoir
- Autotransfusion from ISF to plasma
- Reduced urine production
- Maintenance of CO = tachycardia + inotropy
MINUTES TO HOURS
What are the 3 sensors to acute disturbances in circulating volume?
o LOW + high pressure baroreceptors
o RAA axis
primarily low
Where is Renin released?
What does Renin do to angiotensinogen?
- Released from juxtaglomerular cells
- Cleaves angiotensinogen to make angiotensin I
When ANG I → ANG II, what will this cause?
- Vasoconstriction and aldosterone release
Where is aldosterone released from?
What does it do?
- adrenal cortex
- causes salt and water retention
In the absence of ongoing fluid loss, loss volume should be restored within ______- hours (range).
- 12-72 hours
In the absence of ongoing fluid loss, RBC should be restored through ______________ in ______ weeks (range).
- erythropoeisis
- 4-8 weeks.
What are the Electrolytes and Osmolarity of Normal Saline (0.9%)?
Na = 154 mEq/L
K = 0
Chlorid = 154 mEq/L
Osmolarity = 308 mOsm/L
What are the 4 Electrolytes and Osmolarity of LR?
Na = 130 mEq/L
K = 4 mEq/L
Chloride = 109 mEq/L
Lactate = 28 mEq/L
Osmolarity = 274 mOsm/L
NOT LIVER PTS
What are the 4 Electrolytes and Osmolarity of Plasmalyte?
Na = 140 mEq/L
K = 5 mEq/L
Cl = 98 mEq/L
Acetate = 27 mEq/L
Osmolarity = 295 mOsm/L
What are the Electrolytes and Osmolarity of Albumin 5%?
Na+: 145 +/- 15 mEq/L
K+: <2.5 mEq/L
Cl-: 100 mEq/L
Osmolarity: 330 mOsm/L
What are the Electrolytes and Osmolarity of Hetastarch 6%?
Na+: 154 mEq/L
Cl-: 154 mEq/L
Osmolarity: 310 mOsm/L
What are crystalloids?
- Solutions of electrolytes in water
- The are called balanced solutions (not really though, misnomer)
- LR/plasmalyte = probably considered the most “balanced” crystalloid
What are 2 indications of using crystalloids?
- Replacement of free water and electrolytes
- Volume expansion
Distribution of crysatlloid through entire _______.
what percentage will be in the intravascular space after 20 minutes?
What about after 30 minutes?
- ECF
- 70% in the intravascular space after 20 minutes
- 50% in the intravascular space after 30 minutes
What are the negative effects of crystalloids?
- Tissue Edema (Lungs, GI Tract, Soft Tissues)
- Hypercoagulability (Anticoagulant factors diluted)- micro emboli
NS 0.9% is the most commonly fluid, but what are 5 negative consequence of this fluid?
- Dilutes Hct and Albumin
- Late onset of diuresis
- Increase AKI and dialysis in ICU patients
- Causes hyperchloremic metabolic acidosis if too much is given
- increase in Cl and K concentrations.
What fluid will pull water out of the ICF to the ECF including the plasma?
What does this fluid treat?
- Hypertonic Saline 3%
- hypo-osmolar hyponatremia , inc ICP , TUR syndrome
What is added to LR to act as a buffer?
- Lactate
You want to avoid using this fluid for patients with liver insufficiency.
- LR
- Impair hepatic metabolism will have a hard time metabolism the lactate that is in LR.
- This can cause an increase build of lactate in the patient.
Which fluid will excrete excess water faster than NS d/t the transient decrease in plasma tonicity which suppresses ADH secretion and allow diuresis?
- LR
What happens to dextrose solution when the glucose is metabolized?
- Dextrose becomes a hypotonic solution
* A source of free water - Does not say in the vascular space
- **NOT suitable for volume expansion
- Water moves freely between all compartments**
What fluid could be used for caloric intake in diabetic patients?
- Dextrose 10%
- Better options out there
What are colloids?
- Large molecules of a homogeneous, non-crystalline substance that is dispersed in a second substance (usually a balanced crystalloid).
- Particles cannot be separated (through filtration or centrifuge)
What are two main types of colloids?
- Semisynthetic colloids (Starches)
- Human plasma derivatives (FFP, Albumin)
How do colloids work?
- Increasing colloid oncotic pressure (pulling force),»_space;> increases potential plasma volume expansion
What are 4 negative effects of colloids?
- Causes hemodilution
- Decreases plasma viscosity
- Inhibit RBC aggregation
- Uncertain effect on immune, coag, + renal system - maximum recommended ddoses
What colloid is derived from potatoes or maize (polymers of amylopectin)?
- Hydroxyethyl Starch
The metabolism of hydroxyethyl starch is dependent on ______________.
- Molecular weight of molecules (small, medium, large)
- 70 to 80% of larger molecules are still in the intravascular space at 90 minutes.
- Plasma volume effect last longer
What are the S/E of Hydroxyethyl Starch?
- Coagulopathy through dilution effects
- leading to reduction in VWF, Factor VIII, Clot Strength.
- Renal Dysfunction
DONT give to renal pt or bleeding pt
The dextran is a highly branched __________ produced by a bacteria called _______________.
- polysacchrides
- Leuconostoc Mesenteroides
Dextran have a plasma volume effect similar to that of starches, with a duration of _______ hours (range).
- 6-12 hours
According to lecture, what is Dextran-40 used for?
Why?
- Microvascular Surgery
- Inhibits factor VIII, VWF, Platelet Aggregation prevent coagulation
- coat the RBC and may interfere with cross-matching
What are 3 examples of human plasma derivative colloids?
- Albumin 5%
- FFP
- Immunoglobulin Solution
Indications for human plasma derivatives
- volume replacement
- trauma
- sepsis
- paracentesis
Fluid alterations in the preoperative settings (9).
- Na+ distribution disorder
- Dialysis requirement
- Chronic use of diuretics
- Dx of HTN
- Fasting
- Bowel Prep
- Acute Hemorrhage
- NVD, Suction
- 3rd spacing
Fluid alterations in the intraoperative settings (6).
- Vasodilation from anesthetics
- Sympathetic blockade (narcotics)
- Autoregulatory response
- Acute Hemorrhage
- Insensible Loss
- Inflammation related redistribution
Assessment of Low Intravascular Volume
- Hypovolemia - ↑HR, ↓Pulse Pressure, ↓BP, ↓Cap Refill
- 25% of volume must be lost
- Decreased Urine Output d/t RAA axis
- CVP
- Tissue Perfusion = Lactate, Mixed venous O2
Assessment of High Intravascular Volume (6)
- Increase capillary hydrostatic pressure
- Excess fluids in lungs, bowels, muscle
- Edema
- Reduced tissue oxygenation
- Poor wound healing
- Hypo/Hyper Coagulation
What factors do you need to consider as a CRNA when assessing urine output for intravascular volume?
- Low UO can be d/t stress hormone (cortisol) release from anesthetic
- Low UO can be d/t low intravascular volume and** inadequate perfusion** to the kidney
- Low UO can be d/t the patient’s position, Steep Trendelenburg
When would you use the “classic” fluid therapy?
What’s another name?
- NPO Deficit
- Ongoing maintenance
- Anticipated surgical loss
4-2-1 Rule
NPO Status for Clear Liquids
- 2 hours
NPO Status for Breast Milk
- 4 hours
NPO Status for Infant Formula
- 6 hours
NPO Status for a Light Meal (scramble egg w/toast, coffee w/milk)
- 6 hours
NPO Status for Meat/Fatty, Fried Food, Full Meal
- 8 hours
Formula for Classic Fluid Therapy.
- 1st 10 kg = 4 mL/kg/hr
- 2nd 10kg = 2 mL/kg/hr
- Each kg over 20 kg = 1 mL/kg/hr
4-2-1 RULE
Mr. Cartman’s Weight is 80 kg. Calculate Total NPO deficit using the classic fluid therapy.
Cartman is 80kg, using the 4-2-1 Rule.
4 mL/kg for 1st 10 kg = 40 mL
2 mL/kg for 2nd 10 kg= 20 mL
1 mL/kg for last 60 kg = 60 mL
120 mL/ hr x 8 hours = 960 mL deficit
If Cartman’s fluid deficit is 960 mL and fluid maintenance is 120 mL/hour, what is the fluid plan for this patient?
How much blood would the following hold when estimating blood loss in surgery:
Lap Sponge:
Raytech:
4x4 Gauze:
What to remmeber with suction?
Lap Sponge (packs of 5): 100 mL
Raytech (pack of 10): 20 mL
4x4 Gauze: 10 mL
adding irrigant
%%%
What is the traditional crystalloid replacement ratio for a unit of blood loss preoperatively?
- 3L to 1 unit of blood loss
%%%
How much fluid can be loss with a bowel prep?
- 2000 mL
%%%
What is the fluid deficit for a fever?
- 10% fluid deficit for every 1 degree Celsius above 38C
What are the different categories of evaporative/ redistribution losses?
- Minimal: 0-2 mL/kg/hr (robotics case)
- Moderate: 2-4 mL/kg/hr
- Severe: 4-8 mL/kg/hr (open belly)
evaporative = gut outside body
What is the Parkland Burn Formula?
Adjusted for?
RULE OF 9s
* * 4 mL x kg x TBSA% (whole number) = Fluids to replaced
* 1/2 over the first 8 hours
* 1/2 over the next 16 hours
Formula adjusted for obese + pediatrics patients.
What is the percent body surface area of the entire head and neck?
- 9%
4.5% ea anterior + posterior
What is the percent body surface area of the entire right arm?
Entire Left arm?
- 9%
- 9%
4.5% anterior + posterior !
What is the percent body surface area of the anterior trunk?
Posterior trunk?
- 18%
- 18%
9% ea for upper + lower
What is the percent body surface area of the entire right leg?
Entire left leg?
- 18%
- 18%
9% ea anterior + posterior
What is the percent body surface area of the groin?
- 1%
What fluid is used to replace burn patients?
- Lactated Ringers
When is the Parkland Burn formula used?
- 20% of TBSA is burned
- 2nd and 3rd degree burns only
If an 80kg patient has 20% of their TBSA burned, what would be the total fluid needed to be replaced in this patient?
- 4mL x kg x TBSA (%)
- 4 x 80 x 20 =6400 mL total
- 3200 mL replaced in the first 8 hours
- 3200 mL replaced in the next 16 hours
For goal directed therapy, fluid administration is based on:
- CVP
- CO
- SV
- SVV
Patient will either be fluid responsive or unresponsive. If fluid responsive, a bolus will be administered. Fluid replacement is individualized.
Goal directed therapy fluid admin is based on?
o CVP – not super specific bc distensible
o Swan – use declining - indirect measurement
o Svo2 – measures o2 extraction
o TEE – quantify LV cavity size/EF
o CO
o Lactate levels – decreasing level signals successful resuscitation
o SV machines
o SVV machines – pulse ox/art line use
What have studies shown about the results of goal directed therapy?
- Less AKI
- Less Respiratory Failure
- Decrease Wound Infection
- Decrease Mortality
Goal directed therapy allows decisions to use?
- more fluids
- vasopressors
- inotropes
- blood products
What is the maintenance dose for goal directed therapy?
- 1-3 mL/kg/hr of crystalloid
For goal directed therapy, a fluid challenge of ___________ mL will be used to increase SV.
- 250 mL
What is used in goal directed therapy with blood loss or blood products?
- More likely to replace with colloid or blood products 1:1, rather crystalloids (3:1)
What are the LIMITS to arterial waveform pressure monitoring (SVV Monitoring)?
- Low HR/RR
- Irregular rhythms
- Mechanical Ventilation w/ Low Vt
- Increased Abdominal Pressure
- Thorax Open
- Spontaneous Breathing
Any of these factors will result in an inaccurate reading on the monitor.
What three factors does the arterial waveform pressure monitor take into account to calculate the Stroke Volume Variance?
- Systolic Pressure Variation: difference between lowest systolic peak and highest systolic peak.
- during one cycle of mechanical breath
- Pulse Pressure Variation: difference bw systolic + diastolic bps
- Stroke Volume Variation: The area under the “curve”
What is SVV?
What is normal Stroke Volume Variance (SVV)?
- The variation of SV in 30 seconds
- 10-15%
- If above 15% = fluid (give fluid bolus)
- below 15% = pressors
