Lecture 3: Fluid Management Flashcards
Steps in Acid Base interpretation
is it life threatening? acidemic or alkalemic? acute respiratory? chronic respiratory vs acute metabolic? if acute metabolic, resp compensation? anion gap present? is clinical presentation consistent with interpretation?
Anion gap equation
Na - (Cl + HCO3)
3-11 normal
>12 resp acidosis
Respiratory acidosis
PaCO2 > 45 pH < 7.35 compensated with renal retention of HCO3 decreased contractility, SVR increased PVR treatment: mech vent, HCO3, improve pulm function
Respiratory alkalosis
PaCO2 < 35 pH > 7.45
results in hypokalemia, hypocalcemia, dysrhythmias, bronchoconstriction, cerebrovascular constriction, hypotension
Metabolic acidosis
HCO3 < 21 pH < 7.35
decreased contractility, SVR
increased PVR
treatment: IV fluid, HCO3
Metabolic alkalosis
HCO3 > 27 pH > 7.45
treatment IV fluid, KCl
Base Excess
deviation of HCO3
0 normal
-2 - < 0 metabolic acidosis (base deficit)
> 0 - +2 metabolic alkalosis (base excess)
Who has more water weight?
Infants, men
Body fluid distribution
Of weight
60% TBW
40% intracellular
20% extracellular - 4% plasma, 16% interstitial
Most oncotically active part of ECV?
Albumin
healthy adult fluid requirements
2500ml/day
Maintenance fluid calculations
4 ml/kg/hr for 1st 10kg
2 ml/kg/hr for 2nd 10kg
1 ml/kg/hr for each additional kg
NPO fluid deficit calculation
maintenance fluid rate x hours NPO
Fluid deficit replacement strategy
1/2 in 1st hr
1/4 in 2nd hr
1/4 in 3rd hr
Blood soaked 4x4 volume
~10 ml
Blood soaked laparotomy pad
100-150 ml
Blood spill amounts
1 in = 5 ml
2 in = 20 ml
3 in = 45 ml
4 in = 80 ml
EBV for premature, term
95 ml/kg
85 ml/kg
EBV for infant, child
80 ml/kg
70 ml/kg
EBV for adult male, female
75 ml/kg
65 ml/kg
Allowable blood loss equation
ABL = EBV x (starting Hct - allowable Hct) / starting Hct
Evaporation loss estimations
Short case: 0-2 ml/kg/hr
moderate uncomplicated: 3-5 ml/kg
severe: 6-9 ml/kg
emergency 10-15 ml/kg
Blood loss replacement ratios
crystalloid 3: 1
colloid 1:1
Fluid therapy philosophy
avoidance of sodium and water overload
Goal directed fluid therapy
estimating based on changes to:
Stroke volume variation
pulse pressure variation
systolic pressure variation
Lactated Ringers components
closely resembles plasma
has lactate that converts to HCO3 to buffer
has Ca
Normal Saline large dose
should switch to something else due to chloride content = acidosis
Normosol-R
has Mg, acetate
no Ca
D5W calories
170-200/L
Hypertonic solution uses
used for slow resuscitation
Colloid half life
16 hrs, as short as 2-3 hrs
Albumin risks, sizes, oncotic pressure
allergic reaction, 5%/25% molecular size, 20 pressure
Dextran components
water soluble glucose polymers
Dextran 70 use
volume expansion
Dextran 40 use
prevents thrombosis
less viscosity, good for microvascular cases
Dextran side effects
anaphylactic reaction, platelet inhibition, pulm edema, crossmatching problems
Hetastarch components, problems, max dose, oncotic pressure
plant starch as effective as albumin, less expensive issues with coagulopathy w/ dilutional thrombocytopenia max dose < 20 mg/kg/day 30 oncotic pressure
Benefits of crystalloids
equally effective as colloid for volume
supports U/O better
less side effects
inexpensive
Benefits of colloids
better at restoring severe volume deficits
longer half life
better for low protein
less tissue edema
Blood therapy indication
Mainly to increase oxygen carrying capacity
ASA 2006 guidelines for blood transfusion
rarely indicated for Hgb > 10
always indicated for Hgb < 6
use of trigger not recommended
when appropriate use autologous blood, cell saver, normovolemic dilution
Normovolemic dilution
giving large volume before case to prevent loss of RBCs
Blood administration risks
Hep B, C, HIV, Sepsis, allergic reaction, lung injury, hemolytic reaction, pulm edema
PRBC type, Hct, toxicities
ABO Rh factor, 70% Hct, citrate toxicity - hypocalcemia
Autologous Blood requirement, risks
pt’s own blood, must have Hgb 11 to give
human error, infection
Platelet indication, volume, increased count, risk
<50k, 200-250 ml volume
increases count 7-10k
bacterial risk (not stored cold)
FFP indications, requirement, risk, increased count
replaces all coag factors except platelets must be ABO compatible reverses warfarin give after multiple PRBCs risk: acute lung injury 2-3% increased clotting factors per unit
Cryo components, administration
factor VII, XIII, fibrinogen, von Willebrands
quickly give 200ml/hr
