by gnomey

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What are the normal ranges of TBW by sex?
Females- 46-52%
Males- 52-60%
Infants  70-80%
Why do men have more TBW than females?
On average men have more muscle mass than women.

Muscle, 70%,is composed of more water than fat,10%.
What contains more fluid the intracellular or extracellular compartments?
Intracellular-66%  28L
Extracellular-33%  14L
Plasma 20%            3L
Interstitial 80%        11L
What are the normal blood volumes by sex?
Men 75ml/kg
Women 65ml/kg
Infants  80ml/kg
Neonates 85-95ml/kg
The blood volume is made up of how much plasma and cells?
Whole blood= 3parts cells +4parts plasma

cells to blood=3/7, 48%hematocrit
What is the normal water intake?
Liquids+750ml solid food+350mL genterated metabolcally=
approx 2500-2700/day
What is the normal water loss?
Urine (1400mL, 60%)+feces 100ml+sweat 100ml+insensible=approx 2300ml/day
When is a patient expected to be hypovolemic?
Pt will be hypovolemic pre-op r/t NPO status
What will cause a pt to be hypervolemic?
*uncommon perioperative*

Co-morbidities: RF, CHF, cirrhosis of liver

Other causes, excess IVF, steroids, elevated Na intake
Na concentrations/values
Plasma: 138-146mEq/L

Hyponatremia: <135mEq/L
Hypernatremia: >150mEq/L
K concentrations/values
Plasma: 4mEq/L

Hypokalemia: <3.5mEq/L
Hyperkalemia: >5.5mEq/L
Ca concentrations/values
Plasma: 5mEq/L
Hypercalcemia:iCa>5.6mg/dL, serum Ca>10.5mg/dL
Hypocalcemia: iCa<4.6mg/dL, serum Ca<8.9mg/dl
Types of isotonic solutions?

Intravascular 1/2 life
Types: LR, 0.9Ns, plasmalyte
1/2 life: 20-30min
Types of hypotonic solutions?
1/2 NS, D5W
types of hypertonic solutions?
3% NaCl
D5NS,D5LR,D5 0.45 NS
How do colloids differ from crystalloids?
1. the molecules are too large to pass through intravascular membrane

2. stay in the place they were infused

3. longer half-life, 3-6 hours
what are the 3 types of commonly used colloids?
1. Albumin (5 & 25%)
2. Dextran (40 or 70)
3. Hetastarch
16 hours
how does albumin 5% compare to endogenous albumin's colloid osmotic pressure?
20mmHg (near normal)
What are the indications to use Dextran 40 or 70%?
volume expansion
venous thrombus prophylaxis
What is the max dose for hetastarch?
What are the indications for Hetastarch?
plasma volume expansion
acute isovolemic hemodilution
What are the advantages of using crystalloid?
inexpensive, replace 3rd loss space deficit, promotes urinary flow, extracellular fluid depletion
What are the advantages of using a colloid?
remains in intravascular longer, requires smaller volume for resusiction, used with altered vascular permeability
what are the disadvantages of using a crystalloid?
doesn't remain in the intravascular space long, short half-life, dilutes plasma proteins therefore dilutes capillary osmotic pressure, causes perph edema, increase risk of pulmonary edema
what are the disadvantages of using colloids?
expensive, coagulopathic, allergies (dextran), decrease Ca(albumin), renal failure (dextran), osmotic diuresis, impaired immune response
what is the 4-2-1 rule?
It helps to calculate the intraoperative maintenance fluid requirements for a pt:
4ml/kg/hr for first 10kg
2ml/kg/hr for nest 10kg   so 60ml/20kg/hr
then 1ml/kg/hr
what type of fluid losses does maintenace fluid replacement cover?
GI losses (stool), urine, insensible loss (lung and skin)
How do u calculate NPO deficit? and how do u replace it?
Maintenance fluid rate x npo hours

you give half the amount the first hour, then divide the rest over the next two hours
WHat are the replacement values for intraoperative fluid requirements?
Minimal-cysto,ear,breast biopsy: 0-2ml/kg/hr
Moderate-choley, colostomy, total hip:
Severe-CABG, AAA, surgical trauma
Train wrecks-massive trauma
What are the replacement amounts for blood loss when using colloid or crystalloid?
Coloid 1ml: Blood 1ml
Crystalloid 3ml: Blood 3ml

given after the hour preceding the hour the blood was lost
What factors can help you to assess the patients tolerance of anemia due to surgery and blood loss?
1. How well were you able to maintain intravascular volume
2. Ability to increase CO
3. Increase in 2,3DPG to deliever more 02 to tissues
When should you transfuse blood?
Pt's with normal HCT should only be transfused after losses greater than 10-20% of blood volume

Below Hgb7gm/dl if resting CO has to increase greatly to maintain oxygen delivery

Below Hgb 10gm/dl if pt is elderly or has a significant cardiac or pulmonary disease
How much of an increase in Hct and Hgb levels should you see after blood transfusion?
If patient is given 1PRBC: 1gm Hgb, 2-3%HCT

10ml/kg transfusion of PRBC: 3gm Hgb, 10%Hct
What are interventions are done to monitor clinical evaluation of fluid replacement?
CV: look at BP and HR for changes
Renal: 0.5-1ml/kg/hour of urine
Skin: tugor and musus membranes
Hemodynamic: CVP or PCWP
Lab: Hct and Hgb
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