This document discusses maintenance and replacement fluid therapy in children. It begins by outlining the objectives of understanding the differences in pediatric physiology and the goals of maintenance fluid therapy. It then covers topics like the vulnerability of infants, the distribution of body water, electrolyte concentrations, commonly used IV fluids, and calculating fluid requirements using the 4-2-1 rule. The document emphasizes the importance of monitoring weight, urine output, and serum electrolytes when administering fluids. It also provides guidance on choosing appropriate replacement fluids for issues like diarrhea, vomiting, and altered renal output.
2. OBJECTIVES
To know the difference in physiology of children.
To know the Goals of maintenance fluid therapy.
Able to Calculate total fluid requirement & do
monitoring of the patient.
To know Variations in maintenance water &
electrolytes.
To order Replacement fluids in “common”
situations.
3. WHY THE INFANTS ARE MORE VULNERABLE?*
Physiological inability to concentrate urine.
Higher metabolic rate & larger surface area.
Cant express thirst for more fluids.
Larger turnover.
*IAP text book of Pediatrics 5th edition
4. WHOM TO GIVE MAINTENANCE FLUIDS?
Infants who are sick & whose oral intake is
uncertain.
Babies who are kept NBM for the surgery, with
respiratory distress etc.
neonates kept under radiant warmer.
5. GOALS OF MAINTENANCE FLUIDS*
Prevent dehydration
Prevent electrolyte disturbance
Prevent ketoacidosis
Prevent protein degradation
*Nelsons Text book of pediatrics 19th edition
6. AT BIRTH…
75 % of the total body weight
Obligatory diuretic phase
65 % of the total body weight
Next 2 – 3 Days
At the end of Ist year
60 % of the total body weight
7.
8. BACK TO PHYSIOLOGY…
Total Body Water 60%*
Intra cellular fluid
(ICF)
40%
Extra cellular fluid
(ECF)
20%
Interstitial
15%
Intravasular
5%
*IAP text book of Pediatrics 5th edition
12. KEY LEARNING POINT*
Sodium is the Principle electrolyte in ECF
[140mEq/L (+/- 5)]
Potassium is the Principle electrolyte in ICF
[150mEq/L (+/- 5)]
*IAP text book of Pediatrics 5th edition
13. Maintenance fluids consists of-
i. Water
ii. Glucose
iii. Sodium
iv. Potassium
Advantages –
Simplicity, long shelf life, low cost, compatibility.
Prototypical maintenance therapy fluid doesn’t
provide calcium, phosphorus, magnesium or
bicarbonate.*
*Nelsons Text book of pediatrics 19th edition
15. CONCEPT OF MAINTENANCE OF WATER
Crucial component of maintenance fluid therapy.
Maintenance water = Measurable loss of water 65%
(Urine 60%, stools 5%) + Insensible of water 35% (skin
& lungs)
16. FOR NEONATES
Day 1 60 ml/kg/day
Day 2 90 ml/kg/day
Day 3 120 ml/kg/day
Day 4 150 ml/kg/day (maximum for term infants)
Day 5 to 3 months 150 ml/kg/day
18. Maintenance Fluids
Hourly Maintenance Fluid Requirement*
“4 - 2 -1 rule”
WEIGHT FLUID
0 - 10 kg 4 ml/kg/hr
10 - 20 kg 40ml/hr + 2 ml/kg/hr
> 20 kg 60ml/hr + 1 ml/kg/hr
Upper limit 100cc/hr
*Nelsons Text book of pediatrics 19th edition
19. CONCEPT OF MAINTENANCE OF
ELECTROLYTES
Insensible water loss contains no electrolytes*
So, sodium & potassium present in the urine, stools
& sweat would be the amount to be replaced plus
the sodium & potassium required for normal
metabolism of the body.
3mEq of sodium in 100 cc of fluid
&
2mEq of potassium in 100 cc of fluid
*IAP text book of Pediatrics 5th edition
20. Maintenance fluids usually contains 5% dextrose (5
gm/100ml) providing 17 calories/ 100 ml of fluid.
Which is approx. 20% of the daily caloric needs.
Prevents ketone production.
CONCEPT OF MAINTENANCE OF GLUCOSE*
*Nelsons Text book of pediatrics 19th edition
21. COMMONLY USED FLUIDS FOR
MAINTENANCE*
I. 0.9% Normal Saline – Think of it as ‘Salt and water’
Principal fluid used for intravascular resuscitation and replacement of
salt loss e.g diarrhoea and vomiting
Contains: Na+ 154 mmol/l, Cl- - 154 mmol/l; K+ - Absent, But
K+ is often added
IsoOsmolar compared to normal plasma
Distribution: Stays almost entirely in the Extracellular space
Does not provide free water or calories. Restores NaCl deficits.
*The Harriet Lane Handbook 19th edition
22. CONTENTS OF IV FLUID PREPARATIONS*
Na
(mEq/L)
K
(mEq/L)
Cl
(mEq/L)
HCO3
(mEq/L)
Dextrose
(gm/L)
mOsm/L
NS 154 154 308
DNS 154 154 50 564
½ NS 77 77 143
5%D +
1/2NS
77 77 50 350
D5W 50 278
Ringers
Lactate
(RL)
130 4 109 28 50 273
Iso P 23 20 23 30 50 367
Iso M 37 35 37 30 50 415.5
*The Harriet Lane Handbook 19th edition
23. II. Lactated Ringer’’s (RL): Isotonic, 273 mOsm/L.
Contains 130 mEq/L Na+, 109 mEq/L Cl, 28 mEq/L lactate, and 4
mEq/L K+, 3 mEq/L Ca++
Lactate is used instead of bicarb because it's more stable in IVF
during storage.
Lactate is converted readily to bicarb by the liver.
Has minimal effects on normal body fluid composition and pH. More
closely resembles the electrolyte composition of normal blood serum.
Does not provide calories.
COMMONLY USED FLUIDS FOR MAINTENANCE
24. HOW TO CHOOSE?*
0.9% sodium chloride Suitable for initial volume resuscitation in hypovolaemia
and for ongoing fluid therapy in older children with
normal serum glucose. Fluid of choice in patients with
head injury
5% dextrose + 0.9%
sodium
chloride
Suitable for ongoing fluid therapy in infants and
children, including post-operative cardiac patients. Use
in head injured patients with hypoglycaemia.
5% dextrose + 0.45%
sodium
chloride
Suitable for ongoing fluid therapy in infants and
children, including post-operative cardiac patients
10%dextrose + 0.45%
sodium
chloride
Suitable for ongoing fluid therapy in neonates or older
infants who are hypoglycaemic, including post-operative
cardiac patients
*Leeds Teaching Hospitals NHS Trust Paediatric Intensive Care Units
25. MONITORING WHILE ADMINISTERING FLUIDS*
Child should be weighed prior to the commencement of
therapy, and daily afterwards.
Children with ongoing dehydration/ongoing losses may
need 6 hourly weights to assess hydration status
All children on IV fluids should have serum electrolytes
and glucose checked before commencing the infusion
(typically when the IV is placed) and again within 24 hours
if IV therapy is to continue.
*Royale Children’s Hospital Melbourne Guidelines
26. MONITORING WHILE ADMINISTERING FLUIDS*
For more unwell children, check the electrolytes and
glucose 4-6 hours after commencing, and then according
to results and the clinical situation but at least daily.
Pay particular attention to the serum sodium on measures
of electrolytes. If <135mmol/L (or falling significantly on
repeat measures) If >145mmol/L (or rising significantly on
repeat measures)
Children on iv fluids should have a fluid balance chart
documenting input, ongoing losses and urine output.
*Royale Children’s Hospital Melbourne Guidelines
27. MAINTENANCE FLUIDS & HYPONATREMIA*
Production of ADH leading to water retention
leading to water intoxication.
Patients producing ADH due to subtle volume
depletion can be safely treated with fluids
containing higher sodium concentration, decrease
in fluid rate or the combination of both.
Persistent ADH production due to underlying
disease requires less than total maintenance fluids
Individualization & careful monitoring is must.
*Nelsons Text book of pediatrics 19th edition
28. VARIATIONS IN MAINTENANCE WATER &
ELECTROLYTES
Source Causes of increased water
needs
Causes of decreased water
needs
Skin Radiant warmer Incubator
Phototherapy
Fever
Sweat
Burns
lungs Tachypnea Humidified ventilator
Tracheastomy
GI tract Diarrhea
Vomiting
Nasogastric secretion
renal Polyuria Oligo/anuria
Misc. Surgical drain hypothyroidism
Third spacing
29. REPLACEMENT FLUIDS*
In addition to normal maintenance fluid
requirements, unwell children may need:
Fluid resuscitation for shock
Replacement of pre-existing fluid losses
Replacement of ongoing fluid losses
*Royale Children’s Hospital Melbourne Guidelines
30. REPLACEMENT FLUIDS*
GI losses are accompanied with loss of potassium,
bicarbonate leading to metabolic acidosis.
Impossible to predict the loses for next 24 hrs, so
measure & replace excess GI losses as they occur.
So each ml of the diarrheal stool or the vomitus
should be replaced by the same amount every 1 to
6 hourly.
*Nelsons Text book of pediatrics 19th edition
31. REPLACEMENT FLUIDS
Replacement fluid for Diarrhea*
Average composition of Diarrheal stools (except cholera)
Na 55 mEq/l
K 25 mEq/l
Bicarbonate 15 mEq/l
Approach to Replacement of Ongoing Losses
D5 0.2% NS + 20 mEq/l sodium bicarbonate + 20 mEq/l KCl
Replace stools ml/ml every 1 to 6 hrs
*Nelsons Text book of pediatrics 19th edition
32. REPLACEMENT FLUIDS
Replacement fluid for Emesis or Nasogastric losses*
Average composition of Gastric Fluid
Na 60 mEq/l
K 10 mEq/l
Chloride 90 mEq/l
Approach to Replacement of Ongoing Losses
NS + 10 mEq/l KCl
Replace Output ml/ml every 1 to 6 hrs
*Nelsons Text book of pediatrics 19th edition
33. REPLACEMENT FLUIDS
Replacement fluid for Altered Renal Output*
Oligouria / Anuria
Place patient on insensible fluids (25 to 40% of maintenance)
Replace Urine output ml/ml by half NS
Polyuria
Place patient on insensible fluids (25 to 40% of maintenance)
Measure urine electrolytes
Replace Urine output ml/ml by solution based on measured urine
electrolytes
*Nelsons Text book of pediatrics 19th edition
34. CASE I
5 day old baby boy weighing 3 kg having total
billirubin 18.0 is to be kept under phototherapy.
Baby having no other risk factors & accepts DBM
well.
What fluid at what rate should we prescribe?
35. Rate Day 5 (150 ml/kg/day)
Weight 3 kg
So,
150 * 3 = 750 ml is the total maintainence.
For the babies under phototherapy we should give
half of the maintainence.
So 375 ml/24 hrs i.e 125 ml / 8hrly
Fluid of choice is 5% dextrose + 0.45% NS or iso P
will also be suitable.
36. CASE II
7 year old girl (weight 20 kg) admitted for
bronchopneumonia with respiratory rate of 44/min &
fever of 102 F. later developed 4 episodes of
vomiting (each of 25 ml quantity) & loose stools 3
episodes (each of 80 ml quantity)
37. Weight 20 kg.
So, Total maintenance fluid will be
(100*10) + (50*10) = 1500 ml/ day i.e 500 ml / 8 hrly
Choice of fluid will be 0.45% DNS + 20mEq/L KCl
Replacement fluid for vomiting (each of 25 ml quantity) =
25 * 4 =100 ml of NS + 10 mEq/l KCl
Replacement fluid for loose stools (each of 80 ml
quantity) = 80 * 3 =240 ml of 0.2% DNS + 20 mEq/l
sodium bicarbonate + 20 mEq/l KCl.
38. TACHYPNEA
Respiratory Alkalosis
Increase in rate and
depth of breathing
Loss of CO2
Causes of hyperventilation (tachypnea): Fear, pain, fever, CHF,
anemia
39. FEVER
Each degree of fever increases basal
metabolic rate (BMR) 10%, with a
corresponding fluid requirement
40. VOMITING
Metabolic Alkalosis
Loss of acid from stomach
pH
HCO3
H+
Treatment: Prevent further losses and replace lost
electrolytes
41. DIARRHEA
Metabolic Acidosis
loss of HCO3 from G.I. Tract
pH
HCO3
Treatment: Correct base
deficit, replace losses of
with NaHCO3
42. TAKE HOME MESSAGE
Fluid is like “prescription” so give it with caution.
Children are more vulnerable for rapid fluid loss.
Maintenance calculation by “4-2-1” rule or Holliday Segar’s
formula.
Vigilant Monitoring of WEIGHT, URINE OUTPUT, SERUM
SODIUM CONCENTRATION while giving fluid is must.
As far as possible try to give maintenance fluid requirement
orally.
0.45% DNS + 20 mEq/l KCl is ideal fluid in most of the children
requiring maintenance therapy.
Replacement of fluids should be prompt & appropriate.