Fluids and electrolytes
This fluid is associated with metabolic hyperchloremia
0.9% NaCl because the concentration of Cl in the fluid is higher than that in the plasma. May cause need for CRRT
Daily water requirements (L)
1.5-2.5L
Colloid half life is this long
2-16 hours
Extracellular fluid makes up this percentage of total body weight; this percent of total body water
20% TBWt; 33% TBWater
The extracellular fluid accounts for this much (%) of the total body weight
20% of the total body weight is contributed by this fluid compartment. Interstitial makes up 75% of this percentage, and intravascular makes up 25% of this percentage.
Intravascular half life of crystalloids is this long
20-30 minutes
Daily water requirements
20-30 ml/kg/day
HES max dose
20ml/kg
Normal plasma osmolality
280-290 mOsm/kg
Intracellular fluid makes up this percentage of total body weight; this percent of total body water
40% TBWt; 66% TBWater
The intracellular fluid accounts for this much (%) of the total body weight
40% of the total body weight is contributed by this fluid compartment
Daily potassium requirements
40-80 mEq
EBL: Soaked 4x4 Soaked lap
4x4 = 10ml lost lap = 110-150ml lost
Plasma volume constitutes this percentage of total body weight
5% of total body weight is this compartment
Compensatory intravascular volume expansion administration guideline is this. CVE criticism includes these points
5-7ml/kg Hypotension is due to vasodilation - treat with pressors not fluid. Vasodilation and myocardial depression subside quickly after surgery. May end up with hypervolemia.
By age 50, what percentage of total body weight accounts for water in the human body?
50% of total body weight consists of water in the 50-year old.
Daily sodium requirements
50-100 mEq
Daily glucose requirements
50-100g
This percentage of total body weight is made up of water in the adult male; adult female.
60% of total body weight is made up of water in this population; 50% in this population.
Blood*** volume accounts for this percentage of total body weight; percentage broken down by components
7.5% of total body weight ---2.5% red cell mass ---5% plasma mass
Blood volume is estimated in this manner
70 ml/kg is the estimation for this patient characteristic
Neonates have this percentage of their total body weight as water
70-80% of a newborn's TOTAL BODY WEIGHT is made up of this
This percentage of blood volume is distributed in the venous system; arterial system
85% venous 15% arterial
Argument against classical urine loss consideration
ADH hormone is secreted during surgery, so urine output may not be an accurate or dependable guide for fluid management
4-2-1 rule
Add 40ml to the weight - isotonic Only if patient is over 20kg
Side effects of dextran (colloid)
Anaphylactic reaction*** Increased bleeding times at 20mL/kg Rouleaux formation (interferes with blood xm)
Argument against classical vasodilation consideration
Anesthetic-induced vasodilation is better managed with vasopressor and/or lighter anesthesia to maintain peripheral vascular resistance
Dextran provides this function due to this mechanism
Antithrombosis function Reduces factor VIII and vWF - decreases platelet aggregation and function Acts as plasminogen activator
NS is preferred in these types of patients
Brain injury Hyperkalemic hyponatremia Hypochloremic metabolic alkalosis
Hydroxyethyl starch side effects include these
Coagulation disturbance Renal toxicity - large molecules get stuck Anaphylactoid reactions Interferes with vWF, Factor VIII, and platelet function.
Tonicity is defined as this
Compares osmolarity of the solution to osmolarity of plasma Plasma is isotonic to cells
HES should be avoided in these patients
Critically ill patients Renal patients Patients with sepsis Bleeding risk patients
Crystalloid should replace blood loss at this ratio Colloid at this ratio
Crystalloid 3:1 replacement Colloid 1:1
Extracellular fluid is divided into these two compartments and they make up this percentage of ECF** by total body water (%)
Divided into: 1) Plasma volume - 25% TBWater 2) Interstitial volume - 75% TBWater
Argument against classical NPO status consideration
Fluid deficit in elective surgery is negligible, especially because fasting guidelines allow water ingestion right up until 2 hours before surgery.
Replacement calculation from NPO
Hours NPO x hourly maintenance requirement 1st hour: replace 50% of the deficit 2nd hour: replace 25% of the deficit 3rd hour: replace 25% of the deficit Or give deficit volume at 4x maintenance rate until all deficit is given
Purpose of hypotonic solutions Isotonic Hypertonic
Hypo - free water loss (DI), large water loss Iso - maintenance and replacement fluid Hyper - hyponatremia treatment
These are the three classifications of fluids with explanations
Hypotonic - lower osmolarity Isotonic - balanced osmolarity Hypertonic - high osmolarity
List fluid compartments as their percent of body weight
Intracellular - 40% Extracellular - 20% TOTAL 60% of total body wt. ---Interstitial 15%*** ---Intravascular 5%***
List fluid compartments as percent of total body water
Intracellular 67% Extracellular 33% TOTAL 100% total water ---Interstitial 25%*** ---Intravascular 8%***
Argument against classical 3rd space consideration
It is unlikely that the third space exists
These electrolytes are primarily intracellular
K Mg PO4 Proteins
This fluid should not be run with blood
LR - citrate in blood mixes with Ca in the LR and causes thrombosis
This fluid should not be given to renal failure patients
LR - includes potassium
Fluid calculations are based on this type of body weight for this reason
Lean body weight is used to calculate replacement, this is because fat is anhydrous
Isotonic solutions include these
Lr Normosol Plasma-lyte 0.9% NaCl
MABL
MABL = EBV x (start HCT - target HCT) ___________________________________________ Starting HCT
Evaporative loss guidelines include these
Minimal (craniotomy): 2 ml/kg/hr Moderate (thoracotomy): 4 ml/kg/hr Severe (bowel resection): 6 ml/kg/hr
These are the five classical surgical considerations for fluid status evaluation
NPO status Vasodilation from general or regional anesthesia Evaporative losses 3rd spacing (redistribution IVs --> IS) Blood loss
These electrolytes are primarily extracellular
Na Ca Cl HCO3
These are plasma fluid concentrations of electrolytes
Na - 142 K - 4 Mg - 2 Ca - 5 Cl - 103 HCO3 - 25
Body fluid osmolarity is roughly equal to this
Osmolality is roughly equal to this
These are the three methods of categorizing body water in the patient
Percent of total body weight Percent of total body water Fluid volume in liters
Plasma volume makes up this percentage of ECF weight; interstitial volume (%) of ECF weight
Plasma 75% weight of ECF Interstitial 25% weight of ECF
This compartment is made up a high protein content; example; purpose of protein
Plasma volume compartment is made up of this high molecule content. Albumin is an example. The purpose of this molecule is to provide an oncotic pressure of 20mmHg greater than the interstitial fluid
Preterm EBV Newborn Infant Adult male Adult female
Preterm 95 ml/kg Newborn 85 ml/kg Infant 80 ml/kg Adult male 70 ml/kg
HES side effect that is caused by tissue storage is this
Pruritis - large molecules get stuck in the skin
Blood volume is defined as this
Red blood cell volume + plasma volume = X
This compartment has a low protein content
The interstitial fluid has a low content of this
Argument against classical blood loss consideration - that loss should be replaced with three to four times the amount of crystalloid
There should be an assessment of fluid responsiveness to guide administration of fluid after blood loss
Interstitial fluid makes up this percent of total body weight; this percent of ECF
This compartment makes up 15% of the total body weight This compartment makes up 75% of the ECF
Argument against classical evaporative (insensible) losses consideration
With laparoscopic and other minimally invasive surgery, there is little insensible loss
Osmolarity; osmolality
# osmoles/L # osmoles/kg
