IV fluid management

1. I. V. Fluid Therapy
Dr. Aruna Jain
Director Professor
Lady Hardinge Medical College, New Delhi

2. Terminology
1 mole = 6.02× 1023 molecules
(58gm NaCl, 180gm glucose)
Osmolarity = No. of osmoles of solute/ litre of solution
Osmolality = No. of osmoles of solutes/ kg of solvent
Confusion - ? Interchangeable
Numerical equivalence in body fluid.
• 280- 300 mosm/l or / kg
• Why ? - Negligible solute volume in biological fluid
- Water (Density – 1)
Osmosis / Osmotic pressure ( no. of particles, not type)
Osmoles = amount of osmotically active particles
(1 osmole= molecular weight in gram)
6.02× 1023
molecules

3. Differences between osmolality and tonicity
Osmolality (Chemical term)
• Compared to pure water
• All solute contribute to it.
• Azotemia(no water move)
• Calculated by
• Posm=2*(Na)+ + B. Glu. + Urea
• mmol/l mmol/l mmol/l
• *=Doubled to include osmotic
contribution of chloride.
• =2(140)+90/18 + 19/2.8
• = 290 mosm/kg of water.
Tonicity (Physiological term)
• Compared to plasma
• Only solute which do not cross
cell membrane. (Sodium +
glucose).
• Urea – easily passes
• Tonicity = Total osmolality –
Urea and alcohol
(Ethanol,methanol))
• P. tonicity= 2(Na)+ B.Glu.
• mmol/l mmol/l
• = 285 mosm/kg

4. Differences between osmolality and tonicity
Osmolality (Chemical term)
• Azotemia – Increased BUN –
Hyperosmotic not
hypertonic.
• Urea crosses- increases
osmolality of both I.C.F. and
E.C.F. thus no movement of
water.
Tonicity (Physiological term)
• Osmolal activity of solute
restricted to E. C. F.
(Osmotic force affecting
distribution between I.C.F.
and E.C.F
• Mannitol, Sorbitol
* Glucose – Not permeable through cell mebrane but enter the cell with the
help of carrier protein ( facilitated diffusion)
-Little contribution to total solute of E.C.F.- Sodium principle .
* Mannitol, Sorbitol – Restricted to E.C.F.- contribute to both tonicity and
osmolarity.

5. Distribution of T.B.W ( 70 kg male)

6. Solute composition
I.C.F.V.
• Na (10) HPO4
- (75)
• K+ (140) SO4
- (75)
• Mg+ (40) HCO3
- (10)
• Ca+(2) Cl – (4)
• Protein (16 gm)
E.C.F.V
I.V.
• Na+ (140) Cl- (105)
• K+ (4) HCO3(24)
• Mg+ (2) Protein (7g)
• Ca+ (3) HPO- } ( 8)
• SO4
-}
Int/S
(20)
(2)
(110)
Cellular Membrane
• Selectively permeable to ion
• Not to sodium
• Freely to water
Capillary Endothelium
• Permeable to water, cation, anion soluble
substance like urea, glucose.
• But not to protein
Osmolalities equal in I.C.F. and E.C.F.

7. • Na, Cl, HCO3 – water out of cell – Maintain ECFV
• Large macromolecules (proteins) and K – Determine ICFV
• Total Na content – Determine ECFV , reflects ICFV.
• I.V. I.S
• Plasma oncotic pressure --- Withdraw fluid inward.
• Plasma hydrostatic pressure – Drive fluid outward.
Difference:
• Peripheral – no. of macromolecules ( oncotic gradient)
• CNS – no. of active moles ( osmolar gradient)

8. Practical tips
• RULE 1
• All infused Na+ remains in E.C.F.
• RULE 2
• Water without Na+ expands T.B.W.
(Water crosses until osmolarity is equal on both sides.)

9. COMPARTMENTAL EXPANSION
Fluid ICF ECF Remarks
0.9%NS 0 1000+ Na remains in ECF
1.8%NS 0 1000+ Na remains in ECF
0.45%NS 333+ 666+ 33% TBF is ECF
5%Dex 666+ 333+ 66% TBF is ICF

10. Questions
1. Which I.V. solution would stay only in E.C.F.
2. Which I.V. solution would you give to expand
E.C.F. but to contract I.C.F.
3. Give examples of isotonic, hypotonic and
hypertonic solutions.
4. What proportion of 1 L of 5% Dextrose ends up
in the I.C.F. once the glucose is metabolized.
5. Why uncontrolled diabetics suffer from cellular
dehydration

11. Questions Contd.
6. What mechanism is responsible for excretion of
more water when Furosemide is given?
7. In a patient the plasma Sodium is 160 mmol/l
and he is unaware - ? Right or Wrong.
8. Can serum sodium alone give you idea about
patients volume status?
9. What happens when you give I.V. albumin
solution to
a) Healthy patient
b) Patient with septecimea.

12. Types of fluid
A. According to purpose of use.
i. Maintainence fluid –
a) Normal metabolic need.
b) Replace normal water loss through G.I.T., Kidney, lungs,
cutaneous evaporation+ lesser amount electrolytes.
c) Hypotonic with respect to Na+ . Examples
1) 5% Dextrose (278 mosm/l)
2) 5% Dextrose with small amount of Na+, K+, Ca2+ (less than
plasma) eg. Isolyte M and Isolyte P.
ii. Replacement Fluid –
a) For extra/abnormal losses/ third space loss.
b) Isotonic or slightly hypotonic. Examples
1) Normal Saline Osmolality (280-300 mosm/L) Normal – isotonic
iso osmolar.
2) Ringer Lactate –(278-280 msom/L) composition similar to E.C.F.
3) Balanced crystalloid solution. (K+,Ca2+, Mg2+, Acetate )

13. Types of fluid contd.
iii. Special purpose solution
• Hypertonic
 Containing one or several ingredients to correct specific
imbalance.
Examples
o Hypertonic saline (1.5%or 3%).-513mos/L or 1026mos/L
o Potassium Chloride 20 meq/10 ml-4000 mos/L
o MgSO4 (50%)-4000 mos/L
o Soda Bicarbonate (7.5%) – 1461 mos/L
o 10 % Calcium Chloride. – 2000 mos/L
o 10% calcium Gluconate -680 mos/L
o 10 % Mannitol. – 1000 mos/L.

14. Types of fluid contd.
B. According to effect on plasma volume
1. Plasma substitute. –
a) Crystalloid –Large volume, short half life, E.V. steal
effect.
b) Colloid – ( Iso oncotic Eg. tetra starch, Blood, 5 %
albumin), remain in circulation for sufficient length of
time to stabilize hemodynamics
2. Plasma expander-
(Augmentation of volume by a factor that is greater
than volume of colloid.)
a) Colloid with hyperoncotic property. Eg. Dextran, Heta
and Penta starch.

15. Types of fluid contd.
Crystalloid
i. Crystalline , small molecules
dissolved in water
ii. Aqueous solution of Low
Mol. Wt. with or without
glucose.
iii. Rapidly equilibrate and
redistribute in all
compartments. t1/2 20-30 mins.
iv. Higher volume required for
volume lost.( 3 times)
Colloid
i. Particles in suspension.
ii. High Mol. Wt., contain
proteins, glucose, gelatin,
starch.
iii. Maintains plasma oncotic
pressure and remains in
circulation for long.
iv. Smaller volume required.
C. According to particle size

16. Liquid Glucose Na Cl K Ca Mg Buffer Ph Osmolality
Plasma 140 103 4 5 2 HCO3 25 7.4 290-300
5% Dex 50 - - - - - - 4-4.5 258-278
0.9 % - 154 154 - - - -
5.0-
5.5
308
DNS 50 154 154 - - - - 586
R/L - 130 109 4 3 - L 28 6-6.5 274-280
ISO-P 50 25 22 20 -
A + P + B
( 23 + 3+ 3)
- 368
Plasmal
yte
- 140 98 5 0 3
A+G
( 27+23)
7.4 299
Sterofu
ndin
145 127 4 2.5 1
A + M
(24 + 5)
5.6 309

17. Properties of an ideal plasma substitute
1. Oncotic pr. pH, viscosity- comparable with plasma.
2. Contains Na+,K+ and Ca++ in similar conc. as plasma.
3. Optimal volume effect for clinically adequate (2-4h) length of time.
4. Improves microcirculation.
5. Restores or improves renal function.
6. Does not accumulate in tissues and cells.
7. No dosage limitation.
8. Do not overload CVS sytem.
9. Do not cause edema formation.
10. No interference with haemostasis/coagulation.
11. Do not interfere with or prevent subsequent blood transfusion.

18. Colloid solutions
• ? Oncotic pressure (Exerted by macromolecules)
• Determines movement of fluids across membranes
• Types of colloid.
• Natural colloid – blood
- plasma protein fraction
- fresh frozen plasma
Synthetic colloids – Albumin
- Gelatin
- Dextran
- Starches (HAES steril)

19. Crystalloid Son. Whole blood Albumin Gelatin Dextran HES
Preperati
on
Synthetic Natural
colloid
5% and 25%.
Purified protein
fraction
Synthetic
(Thermal
degradation
of
gelatin(bovin
e)
Modified
polysaccha
rides (End
product of
bacterial
synthesis)
Wax Corn
starch
pH 4.5-6.5 7.4 6.7-7.3 7.2-7.3 4.5-5.7 5.5-7.0/
7.0-7.2
Oncotic
pressure
Nil Iso Oncotic
22-28(25)
5%-Isoonc.
(20),25%-
hyperonc.
(70)
Succinylated
gelfusin Iso
(30)
Haemacel–
isoonc
Dextran-
70-(69)
lomodex
(169)
Heta and
Penta
Hyper(36).
Tetra- iso
(30)
I/V to I/S
fluid
balance
Tissue edema Restored or
maintained
Restored or
maintained
Restored or
maintained
Tissue
dehydratio
n
Tissue
dehydratio
n with heta
and penta
not with
tera
Cvs
overload
Unlikely Unlikely Unlikely Unlikely Potential
risk
Potential
risk(not

20. Crystalloid
Son.
Whole blood Albumin Gelatin Dextran HES
Plasma
½ life
Vol.
effect
Few hrs-days
30%
20-30min
100%
>24hrs- 5/10 d
70%
Upto 12h,
24
30 min -2 hrs
100% 4 h-s
70% 2h -u
6-12 hrs
D40- 200%
for 6-12 h
D70 – 24 h
12-48 hrs
0.7 , 0.5
<150%-
4-6hrs
0.4%
150%-
4-6hrs
Renal fn Not
impaired
Not impaired Not impaired Not
impaired
May be
impaired
Use with
caution in
renal ds.
Effect on
haemost
asis
Possible
factor
activation
Dilution only Dilution only Dilution only Impaired+
dilution
Impaired+
dilution
Accumul
ation in
mono
macro
system
Possible Unlikely Unlikely Unlikely Possible Possible

21. SUMMARY
• Molecular weight
• MW – Arithmetic mean
• Mn – no. of average molecular weight molecule
• Osmolality and oncotic pressure
• All same osmolality
• Oncotic pressure- iv expansion
• Plasma half life
• -Molecular weight
• Route of elimination
• Volume expansion
• Oncotic pressure
• Duration
• Rate of elimination (shortest – gelatin)
• Acid base composition
• Albumin, gelatin – physiological
• Others - acidic

22. SUMMARY
• Electrolyte content
Alb, dextran, heta, penta- Na (154) & Cl (154)
Gelatin- Succinylated- Ca 0.04, K 0.04
Urea link- Ca 6.0, K 5.1
HES- heta & penta- Na & Cl
tetra- balanced crystalloid

24. WATER HOMEOSTASIS
• Normal fluctuations < 0.2 %
• Balance controlled by Tonicity
• Input - ↑tonicity – thirst, ADH
• output – renal ADH system
• 5 L from GUT
- saliva
- bile
- gastric juice
- succus entericus
GIT diseases – NG suction, V & D, gut lumen (intestinal
obstruction)
E.C.F. = 14 L
Sources
Ingested fluid 1300
Solid food 800
Metabolic water 400
Total 2500 ml
Losses
Skin 500
Lungs 400
Urine 1500
Faeces 100
Total 2500 ml

25. Daily Fluid
Requirement(Maintainence)
A. For Adult For 70 kg
– Water 2 ml/kg/ hour 2x70x24 = 2500 ml
– Sodium 1 meq/kg/day = 70 meq
– Potassium 1 meq/kg/day =70 meq
• Fluid
i. 2000 ml of 5D + 500ml NS + KCl 20meq in each vac.
ii. Isolyte M in 5 D. – 2.5 L
Each L contains
Glucose 50 gms Chloride 38 mEq
Sodium 40 mEq Phosphate 15 mEq
Potassium 35 mEq Acetate 20 mEq

26. Paediatric - for 3 kg neonate
Water 4 ml/kg/hour 4X3X24= 300 ml
Na+ 3 mEq/kg/day 3X3 =9 mEq
K+ 2mEq/kg/day 2X3 =6 mEq
Each L of fluid = Supply Na+ 30 K+ 20 , Cl- 20mEq/L
a) Isolyte P in 5% Dextrose (350
mOsm)
Na+ 24 Acetate 21
K + 22 Cl- 22
Mg++ 3 Bisulphite 2
PO4 3
300 ml will supply 1/3rd
concentration of above. i.e. Na+ 8
mEq
b) N/5 in 4 % Dextrose with K+
20mEq/L.
Each L contains Na+ 30 mEq
4% Dextrose
K+ 20 mEq
300 ml will supply
Na+ 9mEq
K + 7 mEq.