6. Biomedical Importance of Water
Homeostasis (CES)
Water distribution
PH maintenance
Maintain Electrolyte Concentration
Set of Fluid Balance
Depletion (dehydration)
Intoxication (over-hydration)
Osmotic & non osmotic mechanism
7. Body Fluid Compartments:
2/3
X 50~70%
lean body weight
TBW
3/4
Male (60%) > female (50%)
TBW(Total Body Water)=0.6xBW
ICF:
55%~75%
1/3
ECF
ICF=0.4xBW
ECF=0.2xBW
1/4
Extravascular
àInterstitial
fluid
Intravascular
àplasma
8. Mr.Iron, 60-Kg male, he has......IVW
Ans:
60Kg x 60%(man) x
1/3(ECF) x 1/4(IV) =
3kg intravascular water
(about 3000 ml plasma)
16. Maintenance Fluid:
Water require, Rule:
100-50-20(60kg=2300ml/day)
100ml/kg/d(for 1st 10kg) +50ml/kg/d(for 2nd 10kg)+20ml/kg/d(per add 1 kg)
4-2-1(60kg=100ml/hr=2400ml/day)
4ml/kg/hr(for 1st 10kg) +2ml/kg/hr(for 2nd 10kg)+1ml/kg/hr(per add 1 kg)
1.5ml/kg/hr(60kg=90ml/hr=2160ml/day)
Electrolytes require:
- Na+: 2-3mmol/kg/day
- K+: 1~2mmol/kg/day
Glucose supplement(if NPO):
100~150g dextrose/per day
"Two stereoisomers (isomeric molecules
whose atomic connectivity is the same but
whose atomic arrangement in space is
different.) of the aldohexose sugars are
known as glucose, only one of which (Dglucose) is biologically active. This form
(D-glucose) is often referred to as dextrose
monohydrate, or, especially in the food
industry, simply dextrose (from
dextrorotatory glucose).
17. Mr.Iron, 60-Kg male, NPO
Maintenance Fluid......
1. Daily Na Requirement=3meq/kg ×60kg=180meq
Daily K Requirement=1meq/kg ×60kg=60meq
2. Maintenance water=2300ml=2.3L
3. 【Na】of fluid=180meq÷2.3L=
78meq/L≒1/2 normal saline
4. 0.9%NaCl=154meq/L
18. MAINTENANCE vs. REPLACEMENT
n Maintenance:
• Provide normal daily requirements:
• Water: 2.5 L
• Sodium ½ or ¼ NS
• KCl 40-60 meq
n Example:
D5 ½ NS with KCL 20 meq/L running at 100 ml/hr
21. Parenteral Fluid Therapy:
Crystalloids:
- contain Na as the main osmotically
active particle
- useful for volume expansion (mainly
interstitial space)
- for maintenance infusion
- correction of electrolyte abnormality
22. Crystalloids:
Isotonic crystalloids
- Lactated Ringer’s, 0.9% NaCl
- only 25% remain intravascularly
Hypertonic saline solutions
- 3% NaCl
Hypotonic solutions
- D5W, 0.45% NaCl
- less than 10% remain intravascularly, inadequate for fluid
resuscitation
23. Colloid Solutions:
Contain high molecular weight
substancesàdo not readily migrate across
capillary walls
Preparations
- Albumin: 5%, 25%
- Dextran
- Gelofusine
- Voluven
28. NPO and other deficits
• NPO deficit =number of hours NPO x
maintenance fluid requirement.
• Bowel prep may result in up to 1 L fluid
loss.
29. Third Space Losses
• Isotonic transfer of ECF from functional body
fluid compartments to non-functional
compartments.
• Depends on location and duration of surgical
procedure, amount of tissue trauma, ambient
temperature, room ventilation.
Department of Anesthesiology
Uniformed Services University of the Health Sciences
30. Replacing Third Space Losses
• Superficial surgical trauma: 1-2 ml/kg/hr
• Minimal Surgical Trauma: 3-4 ml/kg/hr
- head and neck, hernia, knee surgery
• Moderate Surgical Trauma: 5-6 ml/kg/hr
- hysterectomy, chest surgery
• Severe surgical trauma: 8-10 ml/kg/hr (or more)
- AAA repair, nehprectomy
Department of Anesthesiology
Uniformed Services University of the Health Sciences
34. Other factors
• Ongoing fluid losses from other sites:
- gastric drainage
- ostomy output
- diarrhea
- PTGBD, T-tube
• Replace volume per volume with crystalloid solutions
35. Blood Loss
• Replace 3 cc of crystalloid solution per cc of blood
loss (crystalloid solutions leave the intravascular
space)
• When using blood products or colloids replace blood
loss volume per volume
36. Example
• Mr.Michelin, 62 y/o male, 80 kg, for hemicolectomy
• NPO after 2200, surgery at 0800, received bowel prep
• 3 hr. procedure, 500 cc blood loss
• What are his estimated intraoperative fluid
requirements?
37. Example (cont.)
• Ans:
• Fluid deficit: 1.5 ml/kg/hr x 10 hrs = 1200 ml + 1000
ml for bowel prep = 2200 ml
• Maintenance: 1.5 ml/kg/hr x 3hrs = 360mls
• Third Space Losses: 6 ml/kg/hr x 3 hrs =1440 mls
• Blood Loss: 500ml x 3 = 1500ml
• Total = 2200+360+1440+1500=5500mls
41. Orthostatic Hypotension
• Systolic blood pressure decrease of greater than
20mmHg from supine to standing
• Indicates fluid deficit of 6-8% body weight
- Heart rate should increase as a compensatory
measure
- If no increase in heart rate, may indicate
autonomic dysfunction or antihypertensive drug
therapy
42. Clinical Diagnosis of Hypovolemia:
Thorough history taking: poor intake, GI
bleeding…etc
BUN : Creatinine > 20 : 1
- BUN↑: hyperalimentation, glucocorticoid
therapy, UGI bleeding
Increased specific gravity
Increased hematocrit
Electrolytes imbalance
Acid-base disorder
45. Management of Hypervolemia:
Prevention is the best way
Guide fluid therapy with CVP level or
pulmonary wedge pressure
Diuretics
Increase oncotic pressure: FFP or
albumin infusion (may followed by diuretics)
Dialysis
46.
47. Summary
• Fluid therapy is critically important during the
perioperative period.
• The most important goal is to maintain hemodynamic
stability and protect vital organs from hypoperfusion
(heart, liver, brain, kidneys).
• All sources of fluid losses must be accounted for.
• Good fluid management goes a long way toward
preventing problems.