2. Components of
Body Water
ECF
Intravascular fluid: within blood vessels (5%)
Interstitial fluid: between cells - blood vessels (15%)
Transcellular fluid: cerebrospinal, pericardial,
synovial
ICF
Inside cell
Most of body fluid here - 40% weight
Decreased in elderly
3.
4. Body Fluid Composition
Electrolyte :
…is a substance capable of conducting
electric current in solution.
They exist in ions
> Cations : Na+
, K+
, Ca++
etc.
> Anions : Cl-
, HCO3
-
Conc. of electrolytes – expressed in mEq/L
Equivalent weight: wt. of the substance in grams that can combine with or
displace 1 gram of hydrogen.
= atomic weight / valance
For monovalent ions, 1 equivalent = 1 mole
For divalent ions, 1 Eq = 0.5 mol
For trivalent ions, 1 Eq = 0.333 mol
5. Body Fluid Composition
Osmolality :
…is a count of the total number of osmotically
active particles in a solution and is equal to the
sum of the molalities of all the solutes present
in that solution.
Normal = 290 mOsm/Kg
Molarity is the number of particles of a particular
substance in a volume of fluid (mmol / L)
&
Molality is the number of particles disolved in a mass
weight of fluid (mmol / kg)
6. ELECTROLYTE BALANCE
The exchange of interstitial and
intracellular fluid is controlled mainly by the
presence of the electrolytes sodium and
potassium
NaNa++
KK++
NaNa++
KK++
NaNa++
KK++
NaNa++
KK++
8. ELECTROLYTE BALANCE
Potassium is the chief intracellular cation
and sodium the chief extracellular cation
Because the osmotic pressure of the
interstitial space and the ICF are generally
equal, water typically does not enter or
leave the cell
KK++
NaNa++
9. Water is …
At Birth
75% of body wt.
By 2 years
60 % of body wt.
40% ICF
20% ECF
5% Intravascular (plasma)
15% Interstitial
Adult
55% - Males
51% - Females
10. Regulation of Body Water & Electrolytes
For every 100 Cal metabolized, body ..
Loses Gains
65 ml water in urine
40 ml by sweating
15 ml from lungs
5 ml in feces
15 ml from metabolism
Net loss of water = 110 ml per 100 Cal metabolized
11. Fluid Loss
Absolute deficit of ECF
Diarrhoea
Vomiting
Polyuria
Decreased intake
Decrease in effective circulation
Nephrotic syndrome
Cirrhosis of liver
Portal hypertension
14. ELECTROLYTE BALANCE
A change in the concentration of either
electrolyte will cause water to move into or
out of the cell via osmosis
A drop in potassium will cause fluid to
leave the cell whilst a drop in sodium will
cause fluid to enter the cell
KK++
H2O
H2O
H2O
H2O
H2O
H2O
H2O H2O
KK++
KK++
KK++
NaNa++
NaNa++
NaNa++
NaNa++
15. Why Infants are more vulnerable to water loss
Physiological inability of
their renal tubules to
concentrate
Higher metabolic rate
Larger body surface
area
Poorly developed thirst
mechanism
Larger turnover water
exchange
(50% of ECF every day)
16. Dehydration
Water isn’t replaced in body
Fluid shifts from cells to EC space
Cells lose water
Happens in confused, comatose, bedridden
persons along with infants & elderly
19. Signs of Dehydration
Tachycardia
Oliguria
Irritable / lethargic
Sunken eyes and fontanel
Decreased tears
Dry mucus membranes
Mile tenting of skin
Delay in CFT
Cool & pale
Moderate:
20. Signs of Dehydration
Rapid & weak pulse
Decreased BP
No urine output
Very sunken eyes &
fontanel
No tears
Tenting of skin
CFT – very delayed
Cold & mottled skin
Parched mucus
membranes
Severe:
21. Degrees of Dehydration
From treatment point of view, dehydration is
usually classified as :
No dehydration,
Some dehydration and
Severe dehydration.
Some Dehydration
When symptoms and/or signs of dehydration are present.
Severe Dehydration
In the presence of shock and lethargy it is referred to as severe
IMNCI System
23. Oral Rehydration Therapy
ORT is the cheap, simple and effective way to treat
dehydration caused by diarrhoea.
Many of the millions of children who die every year
in developing countries from diarrhoea could be
saved if they were given ORT promptly.
This includes giving extra fluids at home such as
tea, soups, rice water and fruit juices to prevent
dehydration, and the use of Oral Rehydration salts
(ORS) solutions to treat dehydration
24. Physiologic Basis For ORS
Sodium passes into these outermost cells by
co-transport facilitated diffusion via the SGLT1
protein.
The co-transport of sodium into the epithelial
cells via the SGLT1 protein requires glucose.
Two sodium ions and one molecule of
glucose/galactose are transported together
across the cell membrane through the SGLT1
protein.
26. Advantages of Low Osmolar ORS
• Reduces stool output by about 25% when
compared to the standard WHO ORS.
• Reduces vomiting by almost 30%
• Reduces the need for IV therapy by > 30%.
• Results in reduced hospitalization
27. Super ORS
… are the special types of ORS which instead of mono-sugars
contain more complex sugars. They may be Food- based ( as
rice-based ) or otherwise be starch-free (Glycine / alanine based
or Glucose polymer based
Advantages of Super-ORS
Provides rehydration.
Helps in reducing the stool output, frequency of stools and
duration of diarrhea.
Furnishes increased amount of calories (180 kcal/ litre)
Contributes to weight gain, as it provides additional nutrition (thus
is especially useful for those who are malnourished).
With gradual release of glucose, prevents secondary disaccharide
intolerance.
Disadvantages
Short shelf-life (not exceeding 10 hours)
28. Resomal
An oral rehydration salt (ORS) adapted to the needs of
the severely malnourished patients.
Ingredient Amount
Water (boiled & cooled) 2 litres
WHO-ORS One 1 litre-packet
Sugar 50 g
Electrolyte/mineral solution 40 ml
(K, Mg and Zn)
ReSoMal contains approximately 45 mmol Na, 40 mmol K
and 3 mmol Mg/litre
ReSoMal solution must only be given orally in small sips / by NG tube.
29.
30. Management of Diarrhoea
Plan A: Treat Diarrhoea at Home
Plan B: Treat Some Dehydration with ORS
Plan C: Treat Severe Dehydration Quickly
31. ORT to prevent Dehydration – Plan A
Counsel the mother 4 rules of Home Treatment
1. Give Extra fluid (as much as the child takes)
2. Give Zinc supplements
3. Continue Feeding
4. When to Return
32. ORT to prevent Dehydration – Plan A
1. Give Extra fluid (as much as the child takes)
1. Tell mother to breast feed, give ORS, food based fluids
(soup, rice water, yoghurt drinks), or clean water
2. Teach mother how to mix and give ORS
3. Show how much extra fluid to give in addition to usual
fluid intake
1. Upto 2 yrs : 50 – 100 ml after each loose stool
2. 2 yrs or more : 100 – 200 ml
33. ORT to prevent Dehydration – Plan A
2. Give Zinc Supplements
1. Tell mother how much zinc to give
1. Up to 6 mo : ½ tab per day for 14 days
2. 6 mo and > : 1 tab per day for 14 days
2. Show mother how to give zinc supplements
3. Remind mother to give zinc for full 14 days
34. ORT to prevent Dehydration – Plan A
3. Continue Feeding
4. When to Return
1. Immediately :
1. Child is not able to drink or breastfeed
2. Child becomes sicker
3. if blood per stool or
4. drinking poorly
2. After 5 days : if diarrhoea persists
35. Prevention of dehydration – Plan A
Age Amt of ORS after
each stool
< 24mo 50 - 100ml
2yr -10yr 100 - 200ml
> 10yrs As much as wanted
How much ORS ?
36. ORT to prevent Dehydration – Plan B
for Patients with physical signs of Dehydration
a) Correction of existing water and electrolyte
deficit as indicated by the presence of signs of
dehydration
b) Replacement of ongoing losses due to
continuing diarrhoea to prevent recurrence of
dehydration
c) Provision of normal daily fluid requirement
37. Weight Wt 6 kg 6 – 10 kg 10 – 12 lg 12 – 19 kg
Use child’s age only when you do not know the weight.
Approx amt of ORS required (ml) = Child’s Wt. in Kg. X 75
38. SOME DEHYDRATION: PLAN B
ORS: 75ml/kg plus
for ongoing losses
(50ml/stool)
one liter of potable
water + one full
sachet of ORS to be
dissolved & kept in a
container with lid.
39. When is ORT ineffective ?
High stool purge rate ( > 5 ml/kg/hr)
Persistent vomitings ( > 3 / hr)
Incorrect preparation of ORS
Abdominal distension
Glucose malabsorption
40. Children with Severe Dehydration – Plan C
Start IV fluids immediately
While drip is being set up give ORS
of child can drink
42. Principles Of Rehydration
1. Step I
• Restore intravascular volume
• Normal saline (20ml/kg) over 20 minutes
(Repeat until intravascular volume restored)
2. Step II
• Calculate 24 hour water needs (maintenance &
deficit)
• Calculate 24 hour electrolyte needs
• Both maintenance & Deficit sodium and potassium
• Subtract the fluid volume/ electrolyte concentration
used in resuscitation phase.
3. Step III
• Replace ongoing losses
43. Electrolyte Deficit
Rapid Dehydration (< 2 days)
Ratio of ECF to ICF deficit is 75 : 25 %
Moderately Rapid Dehydration (2-7 days)
Ratio of ECF / ICF is 60 : 40 %
Slow Dehydration (>7days)
Ratio of ECF / ICF is 50 : 50 %
44. Classification of Dehydration based on Tonicity
Isonatremic (Isotonic) Dehydration
Serum Na =135 to 145 mEq./L
Hyponatremic (Hypotonic) Dehydration
Serum Na < 130 mEq./L
Hypernatremic (Hypertonic) Dehydration
Serum Na >145 mEq./L
45. Concept of Maintenance Fluids
Principles of Therapy -2. MAINTENANCE
Calculation based on caloric expenditure
46. Concept of Maintenance Fluids
Calculation based on caloric expenditure
[ Holiday & Segar Formula ]
Wt. Calories Expended Maintenance waterWt. Calories Expended Maintenance water
Till 10 Kg 100 Cal / Kg 100 ml / Kg
10 – 20 Kg 1000 Cal + 50 Cal for 1000 ml + 50 ml for
Every Kg > 10 / Kg Every Kg >10 / Kg
20 Kg 1500 Cal + 20 Cal for 1500 ml + 20 ml for
every Kg above 20 Kg every Kg above 20 Kg
47. Concept of Maintenance Fluids
Route Water Na K
Evaporative
Lungs
Skin
15
40
0
0.1
0
0.2
Stool 5 0.1 0.2
Urine 65 3.0 2.0
TOTAL 125 3.2 2.4
Less Metabolic Water 10 – 15
110 - 115
Loss per 100 Cal. of metabolism per Day
48. Concept of Maintenance Fluids
Calculation based on caloric expenditure
[ Holiday & Segar Formula ]
Wt Water (ml /day) Water
ml / hr
Electrolytes
mEq / L of water
0 – 10 kg 100 ml / kg 4 / kg Na 30, K 20
10 – 20 kg 1000 + 50 ml /kg for
each kg above 10
40 + 2 / kg
for each kg
above 10
Na 30, K 20
> 20 kg 1500 + 20 ml /kg for
each kg above 20
60 + 1 / kg
for each kg
above 10
Na 30, K 20
Baseline estimates are affected by fever (increasing by 12% for each degree
> 37.8° C), hypothermia, and activity (eg, increased for hyperthyroidism or
status epilepticus, decreased for coma).
49. Concept of Maintenance Fluids
Example : 22 kg child
For the first 10 kg: 10 X 100 = 1000 ml
For the second 10 kg 10 X 50 = 500 ml
For every kg > 20 2 X 20 = 40 ml
TOTAL = 1540 ml / 24 hrs
i.e. = 64 ml / hr maintenance fluid
50. Concept of Maintenance Electrolytes
Insensible water losses contain no electrolytes
Na+
and K+
losses are those present in urine,
feces and sweat.
•3 mEq of Na in 100 ml of fluid
•2 mEq of K in 100 ml of fluid
51. Maintenance Fluid and Glucose
Maintenance fluid must contain glucose –
To prevent hypoglycemia
To prevent catabolism by providing calories
• If 20 % of caloric requirement is met, tissue catabolism
can be avoided
• 5 g of glucose (provide 20 Cal. Is added to 100 ml of
maintenance fluid)
52. Concept of Maintenance Fluids
Composition
Differs from solutions used to replace deficits
and ongoing losses.
Patients require
Na 3 mEq/100 kcal/24 h (3 mEq/100 mL/24 h)
and
K 2 mEq/100 kcal/24 h (2 mEq/100 mL/24 h).
This need is met by using 0.2% to 0.3%
saline with 20 mEq / L of K in a 5% dextrose
solution.
Other electrolytes (eg, Mg, Ca) are not
routinely added.
53. Maintenance Fluid and Glucose
Maintenance fluid Choice –
< 1 yr : 0.2% NaCl, 5% D/W plus 2 mEq KCl / 100 ml
> 1 yr : 0.33% NaCl, 5% D/W plus 2 mEq KCl / 100 ml
> 3 yr : 0.45% NaCl, 5% D/W plus 2 mEq KCl / 100 ml
Rate : at 64 ml / hr
54. Calculating Deficit, Maintenance and
Total Electrolytes
Moderately Rapid (2-7 days)
Therefore ECF / ICF Ration is 60 / 40 %
Deficit Water is 1000 ml
ECF Component is 60% (600 ml) and
ICF component is 40% (400 ml)
Principle electrolyte in ECF is Na which is 140 mEq/L
For 600 ml = 84 mEq.
Principle electrolyte in ICF is K which is 150 mEq/L
For 400 ml = 60 mEq.
55. Calculating Deficit, Maintenance and
Total Electrolytes
Maintenance / d 1000 30 20
ECF Water Deficit 600 84 -
ICF Water Deficit 400 - 60
Total 2000 114 80
H2O Na K
ml mEq mEq
56. Na+
K
+
Cl
-
Bicarb++ Ca
++
G/100 ml mOsml/L
D5-W 5 252
D10-W 10 505
Normal Saline (0.9%) 154 154 308
0.45% Na Chloride 77 77 154
0.45% Na Cl + 5% Dex 77 77 5 400
0.33% Na Cl + 5% Dex 56 56 5 350
D5-Normal Saline 154 154 560
D5-0 45% Na Chloride 77 77 406
D5-0.2% Na Chloride 34 34 321
D5-Ringer's Lactate 130 4 109 28 2.7 525
Ringer's Lactate 130 4 109 28 2.7 273
3% Na Chloride 513 513 1027
Ready Mixed Solutions (Electrolyte Content is meq per Liter)
57. Fluid Therapy
Phase 1 : (Shock Therapy)
Restoration of volume - 1 to 2 hrs
20 ml / Kg N.Saline or R.L. rapid IV
58. Fluid Therapy
Phase 2 :
Replacement of ½ the calculated fluid loss
(Deficit + Maintenance) in first 8 hrs.
59. Fluid Therapy
Phase 3 :
Replacement of ½ the calculated fluid loss
(Deficit + Maintenance) in next 16 hrs
Replacement of K+
(after voiding with a max. of 40mEq/L)
Half the potassium deficit is replaced in 1st
day
60. Calculating pre-illness weight:
Eg. Infant with moderate isonatremic dehydration –
weighing now 5.3 kg
Pre illness weight is say ‘X’
X / 5.3 = 100 / 90
X = 530 / 90 = 5.9 kg.
Deficit is (10 % Dehydration) = 600 ml.
Maintenance fluid = 600 ml (Holideay& Segar)
61. Eg. 10 Kg child
Phase 1 (1st
hr)
20 ml / Kg of NS
(200 ml of NS, 31 mEq. of Na)
Phase 2 (2-8 hrs)
Replace half the fluid loss in next 7 hrs
900 ml in 7 hrs That is 129 ml / hr
We like to add Na in a conc of 46 mEq. L
(which is roughly in 1/3rd
NS
We can use 1/3 NS in 5% D/W at 129 ml / hr.
Phase 3 (hrs. 9-24) [ patient voids ]
Replace remaining half of fluid loss and add K now
900 ml over 16 hrs of D5, 1/3 NS at 56ml/hr
(Pt has 25mEq/L of K loss. We are replacing 900 ml (roughly 1 L) of
fluid we may chose 25mEq./L of KCl
62. Treating Hypotonic Dehydration
(S. Na+ < 130 mEq/L)
First calculate the total fluids and electrolytes needed for
isonatremic dehydration plus maintenance fluids.
Then use the following formula to raise the serum sodium:
Wt (kg) x 0.6 x desired mEq increase in serum Na+
After correction of shock, prefer ½ N DNS rather than 1/3 N DNS
If child is convulsing : 3ml/Kg of 3% Nacl over 10-15 min
Raising the S.Na by 5 mEq/L is sufficient to control symptoms.
63. Treating Hypertonic Dehydration
(S. Na+ > 150 mEq/L)
This type of dehydration is usually the most serious and
correction should be done with caution. Rapid correction
May result in CNS problems.
Generally, elevated serum sodium should be lowered no faster
than 15 mEq/L in 24 hours.
One simple way is to calculate the total maintenance and deficit
fluid and electrolytes that would be used in isotonic dehydration
but keep sodium at maintenance levels.
Give deficit fluid over 48 hrs rater than 24 hrs
Hydrating fluid must contain Na +
64. Treating Potassium Deficits
Regardless of the deficit, the usual maximum
concentration of K+ is 4 mEq per 100 ml of IV
fluid (for peripheral infusion).
For most instances 2-3mEq per 100 ml will
suffice.
In cases of hypokalemia higher levels can be
used, but the heart should be monitored.
Before giving potassium be aware of the
possible existence of renal failure.
65. Replacement of ongoing losses
Average composition of diarrhoeal stools
Na+ 55 meq/l
K+ 25 meq/l
HCO3 15 meq/l
Fluid for replacement (ml/ml every 1-6
hourly)
D 5 with 1/4 NS + 15 meq /l bicarbonate +
25 meq/l of KCL.
66. Priniciples of Rehydration - Summary
Select an appropriate fluid (based on total
water and electrolyte needs)
Administer half the calculated fluid during
the first 8 hours
Administer the remainder over the next 16
hours
Don’t add KCL until the child voids urine.