Post on 24-May-2015
Fluid & Electrolyte TherapyFluid & Electrolyte Therapy
• C.S.N.VittalC.S.N.Vittal• C.S.N.VittalC.S.N.Vittal
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
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/LEquivalent 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
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)
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++
Body Fluid CompartmentsPlasma Interstitial Fluid Intracellular Fluid
Na+
142
K+5
Ca++ 5
Mg++ 3
HCO3 –
24
Cl – 105
Protein 15
SO4 – 4
R – 2
HPO4 – 5
Na+
144
K+5
Ca++ 5
Mg++ 3
HCO3 –
27
Cl – 118
SO4 – 4
R – 2
HPO4 – 5
Na+6
K+154
Mg++ 3
HCO3 –
24
Protein 15
R – 4
HPO4 – 106
SO4 – 17
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++
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
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
Fluid Loss Absolute deficit of ECF
Diarrhoea Vomiting Polyuria Decreased intake
Decrease in effective circulation Nephrotic syndrome Cirrhosis of liver Portal hypertension
Fluid Regulation
Antidiuretic hormone Aldosterone (Renin – Angiotensin) Atrial natruretic peptide Thirst mechanism Hypothalamus
Fluid Regulation
ANP
ADH Aldosterone(Renin – AT)
Hypothelamus
Thirst
KK++
NaNa++
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++
H2OH2O
H2O H2O
H2O
H2O
H2O H2O
KK++
KK++
KK++
NaNa++
NaNa++NaNa++
NaNa++
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)
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
Degrees of Dehydration
Mild 3 – 5 % Moderate 7 – 10 % Severe 10 – 15 %
Symptoms of Dehydration
Restlessness Excessive Thirst Oliguria Fever ±
Mild:
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:
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:
Degrees of DehydrationFrom 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
Diarrhoea Treatment Instructions
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
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.
WHO ORS Formulae - comparison
Standard ORS(g/L) --- (mEq/L)
Reduced osmolarity ORS (2003)
Sodium Chloride
2.6 90 75
Chloride 80 65
Potassium chloride
1.5 20 20
Trisodium Citrate
2.9 10 10
Anhydrous Glucose
13.5 111 75
Total Osmolarity 311 245
(All values in mmol / litre)
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
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)
Resomal An oral rehydration salt (ORS) adapted to the needs of
the severely malnourished patients.Ingredient AmountWater (boiled & cooled) 2 litresWHO-ORS One 1 litre-packetSugar 50 gElectrolyte/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.
Management of Diarrhoea
Plan A: Treat Diarrhoea at Home
Plan B: Treat Some Dehydration with ORS
Plan C: Treat Severe Dehydration Quickly
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
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
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
ORT to prevent Dehydration – Plan A3. 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
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 ?
ORT to prevent Dehydration – Plan Bfor Patients with physical signs of Dehydrationa) 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
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
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.
When is ORT ineffective ?
High stool purge rate ( > 5 ml/kg/hr) Persistent vomitings ( > 3 / hr) Incorrect preparation of ORS Abdominal distension Glucose malabsorption
Children with Severe Dehydration – Plan C
Start IV fluids immediately
While drip is being set up give ORS of child can drink
Parenteral Fluid Therapy
1. Deficit
2. Maintenance
3. Ongoing losses replacement
Principles Of Rehydration1. 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
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 %
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
Concept of Maintenance Fluids
Principles of Therapy -2. MAINTENANCE
Calculation based on caloric expenditure
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
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 2.4Less Metabolic Water 10 – 15
110 - 115
Loss per 100 Cal. of metabolism per Day
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).
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
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
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)
Concept of Maintenance FluidsComposition 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.
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
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.
Calculating Deficit, Maintenance and Total Electrolytes
Maintenance / d 1000 3020
ECF Water Deficit 600 84 - ICF Water Deficit 400 - 60
Total 2000 114 80
H2O Na K ml mEq mEq
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)
Fluid Therapy
Phase 1 : (Shock Therapy)
Restoration of volume - 1 to 2 hrs
20 ml / Kg N.Saline or R.L. rapid IV
Fluid Therapy
Phase 2 :
Replacement of ½ the calculated fluid loss
(Deficit + Maintenance) in first 8 hrs.
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
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)
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
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.
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 +
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.
Replacement of ongoing lossesAverage 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.
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.
- Vittal- Vittal