Fluid and electrolyte

1. Electrolyte Abnormalities in
Children and Fluid therapy
Presenter- Sushanta Paudel

2. Composition of body fluids
🠶Total body water as a percentage of body weight
declines with age.
 Early fetal life TBW= 90%
 At birth TBW= 75-80%
 By the end of 1st year to puberty TBW= 60%

3. Body Composition
40%Intracellular
15% Interstitial
40% Intracellular
fluid
Body Composition
5% Intravascular
Intracellular fluid
Interstitial fluid
Non Water
Intravascular volume

4. Water balance
Input Output
Water intake:
Fluid 60%
Food 30%
Urine 60%
Stool 8%
Sweat 4%
Water of
oxidation 10
%
Insensible
loss 28%
(skin, lungs)
Water intake is
regulated by
osmoreceptors in
hypothalamus
Water loss is
regulated by ADH
from post.
pituitary

5. Electrolyte composition of extracellular and intracellular fluid
compartments
4 2.5 1.1
104
24
14
6
2
160
140
140
120
100
80
60
40
20
0
mmol/
l
Plasma
140
13
7
107
40
10
3
160
140
120
100
80
60
40
20
0
mmol/
l
Intracellular

6. Osmolality
🠶 Osmolality is the solute concentration of a fluid expressed
as mOsm/kg.
🠶 Fluid/water moves from lower osmolality to higher
osmolality across biological membranes.
🠶 Normal Plasma osmolality = 285 to 295 mOsm/kg
🠶 Tightly regulated within 1-2% of normal.
Sosm = (2 x Na+) + (BUN / 2.8) + (Glu / 18)

7. Regulation of sodium and water balance

8. Maintenance fluid & electrolyte
requirements
🠶 Holliday-Segar method
🠶 Maximum fluid/day = 2400ml/day
Body weight Per day Per hour
0-10 kg 100ml/kg 4ml/kg
10-20 kg 50 ml/kg beyond 10 kg
2ml/kg beyond
>20 kg 20ml/kg beyond 20 kg
1ml/kg beyond

9. Maintenance fluid & electrolyte
requirements
🠶 Daily sodium requirement = 3meq/kg (children)
🠶 Daily potassium requirement = 2meq/kg
🠶 Daily chloride requirement = 2meq/kg

10. Maintenance fluid & electrolyte
requirements
🠶 Fluid/electrolyte requirements calculated on Holliday-segar
method are generally hypotonic (N/4 or N/5)
🠶 Recent evidence shows use of hypotonic fluids esp. in sick
children can cause hyponatremia.
🠶 0.9% NS can be safely used in standard maintenence
volume.
(except in CHF, renal/hepatic failure, diabetes insipidus).

11. Maintenance fluid & electrolyte
requirements
🠶 No single i.v fluid is suitable in all situations, therapy to be
individualized.
🠶 Monitor with daily wt, input/output, serum electrolytes.
🠶 Maintenance fluids provide only about 20% of calories, therefore
child will lose wt due to catabolism.

12. Conditions that alter maintenance
fluid requirements
🠶 Increased fluid requirement
 Fever (10-15% per 0C above
380C )
 Radiant warmer/Phototherapy
 Burns
 Excessive sweating
 High physical activity
 Hyperventilation
 Diarrhoea/vomiting
 Polyuria
 VLBW babies

13. Conditions that alter maintenance
fluid requirements
🠶 Decreased fluid requirement
 Oliguria/Anuria
 Humidified ventilator/incubator
 Hupothyroidism

14. Sodium
🠶 Most abundant ion of the extracellular compartment
🠶 Normal serum sodium = 135 to 145 mEq/l.
🠶 Daialy sodium requirement is 2 to 3 mEq/kg body weight.
🠶 Requirement is nearly 2 to 3 fold higher in term & VLBW
preterm babies.
🠶 Adult requirements decreases to 1.5mEq/kg/day.
🠶 Extrarenal sodium losses can be significant via profuse
sweating ,burns, severe vomiting or diarrhoea.

15. Hyponatremia
🠶 Defined as serum Na < 135 meq/l.
🠶 Usually symptomatic when Na is < 125mEq/l or the decline is
acute(<24 hour).
🠶 Early features : headache, nausea, vomiting, lethargy and
confusion.
🠶 Advance manifestations: seizures, coma, decorticate posturing,
dilated pupil, anisocoria, papilledema, cardiac arrhythmias,
myocardial ischemias and central diabetes insipidus.

16. Hyponatremia
🠶 CAUSES of hyponatremia
 Hypovolemic hyponatremia
🠶 Renal loss: diuretic use, osmotic diuresis, renal salt
wasting, adrenal insufficiency.
🠶 Extra-renal loss: diarrhoea, vomiting, sweat,cerebral salt
wasting syndrome, third spacing(effusion,ascites)

17. Hyponatremia
🠶 CAUSES of hyponatremia
 Normovolemic hyponatremia
🠶 Conditions that predispose to SIADH - Inflammatory central
nervous system disease(meningitis, encephalitis), tumors,
pulmonary disease(severe asthma, pneumonia),drugs
(cyclophosphamide, vincristine).

18. Hyponatremia
🠶 CAUSES of hyponatremia
 Hypervolemic hyponatremia
🠶 CHF, Cirrhosis, Nephrotic syndrome, Acute or chronic
renal failure

19. Hyponatremia-Treatment
🠶 Determine whether hyponatremia is acute(<24 hr) or chronic(>48hr),
symptomatic/asymptomatic.
🠶 Evaluate the volume status (hypervolemia, euvolemia, hypovolemia).
🠶 Sodium deficit (meq) = 0.6*Body wt(kg) * [desired Na – observed Na]

20. Hyponatremia-Treatment
🠶 Treat hypotension first (NS/RL/5%albumin), asymptomatic cases
prefer ORS.
🠶 Rate of correction = 0.6 to 1.0 mEq/l/hr till Na is 125 then at slower
rate over 48 to 72 hours.
🠶 For symptomatic cases give 3%NS @ 3-5 ml/kg over 1-2 hr. (increases
serum Na by 5-6mEq/l)
🠶 Stop further therapy with 3%NS when patient is symptom free or
acute rise in serum sodium is 10mEq/l in first 5 hour.

21. Hyponatremia-Treatment
🠶 Rise in serum Na can be estimated by Adrogue Madias formula-
Δ 𝑁𝑎 =
𝐼𝑛𝑓𝑢𝑠𝑎𝑡𝑒 𝑁𝑎 + 𝐼𝑛𝑓𝑢𝑠𝑎𝑡𝑒 𝐾 −𝑆𝑒𝑟𝑢𝑚 𝑁𝑎
[𝑇𝐵𝑊+1]
Δ[Na]= expected change in serum sodium/L of fluid given
TBW= total body water is 0.6*Body wt (kg)

22. Hyponatremia-Treatment
🠶 Fluid restriction alone is needed for SIADH.
🠶 Sodium and water restriction for hypervolemic hyponatremia.
🠶 V2-receptor antagonists or vaptans may be used in SIADH &
hypervolemic hyponatremia.
🠶 Diuretics for refractory cases.

23. Hypernatremia
🠶 Defined as serum Na >150mEq/l
Clinical features
🠶 Lethargy or mental status change which can proceed to coma and
convulsions.
🠶 Acute severe hypernatremia leads to osmotic shift of water from
neurons causing shrinkage of brain and tearing of meningeal vessels -
intracranial hemorrhage.

24. Hypernatremia
🠶 Causes of Hypernatremia
 Net water loss
🠶 Insensible losses
🠶 Diabetes insipidus
🠶 Inadequate breastfeeding
🠶 Hypotonic fluid loss
🠶 Renal: osmotic diuretics, post obstructive, polyuric phase of acute tubular
necrosis
🠶 GI: vomiting,nasogastric drainage, diarrhea, laxative.

25. Hypernatremia
🠶 Causes of Hypernatremia
 Hypertonic Sodium gain
🠶 Excess sodium intake
🠶 Sodium bicarbonate, saline infusion
🠶 Hypertonic feeds, boiled skimmed milk
🠶 Ingestion of sodium chloride
🠶 Hypertonic dialysis
🠶 Endocrine: Primary hyperaldosteronism, Cushing syndrome

26. Hypernatremia- Treatment
🠶 Treat hypotension first (NS/RL/5% Albumin bolus)
🠶 Correct deficit over 48 to 72 hours. Recommended rate of drop is
0.5mEq/l/hr (10-12mEq/l/day)
🠶 Hypotonic infusates are used as N/4 or N/5 saline, avoid sodium free
fluids. ( Calculate expected fall in Na by Adrogue Madias formula ).

27. Hypernatremia- Treatment
🠶 Seizures during correction of hypernatremia are treated using
3%NS as 5-6ml/kg infusion over 1-2 hr.
🠶 For significant hypernatremia ( >180-200mEq/l ) with concurrent
renal failure and or volume overload, renal replacement therapy
(peritoneal or hemodialysis, hemofiltration) is indicated.

28. Differentiation b/w few important conditions

29. Potassium
🠶 Normal serum concentration=3.5-5.0mEq/l and intracellular 150mEq/l .
🠶 Source of potassium include meats, beans, fruits and potatoes.
🠶 Majority in muscles and majority of extracellular K in bones.
🠶 More significant in males around puberty.
🠶 Serum K concentration increases by approximately 0.6mEq/l with each
10 mOsm rise in plasma osmolality

30. Physiologic function of Potassium
🠶 Electrical responsiveness of nerve and muscle cells.
🠶 Contractility of cardiac, skeletal and smooth muscle cells.
🠶 Maintains cell volume.

31. Potassium Excretion
🠶 Normally 10% of K is excreted.
🠶 Excretion is increased by aldosterone, loop diuretics, osmotic diuresis,
glucocorticoids, ADH and delivery of negatively charged ions to the
collecting duct(e.g. bicarb).
🠶 Insulin, ß agonists and alkalosis enhance potassium entry into cells.

32. Hypokalemia
🠶 Serum K<3.5mEq/l.
🠶 Clinical features
🠶 Severe hypokalemia (<2.5mEq/l) cause muscle weakness (neck
flop, abdominal distension, ileus) and arrhythmia.
🠶 Hypokalemia increases the risk of digoxin toxicity by promoting
its binding to myocyte, potentiating its action and decreasing its
clearance.

33. Hypokalemia
🠶 ECG changes-

34. Hypokalemia
🠶 The trans-tubular potassium gradient (TTKG) is used to
interpret urinary potassium concentration.
𝑈𝑟𝑖𝑛𝑒 𝐾 ∗ 𝑆𝑒𝑟𝑢𝑚 𝑂𝑠𝑚
TTKG = 𝑆𝑒𝑟𝑢𝑚 𝐾 ∗ 𝑈𝑟𝑖𝑛𝑒 𝑂𝑠𝑚
🠶 TTKG<4 suggest that kidney is not wasting excessive
potassium, TTKG ≥4 signify renal loss.

35. Causes of Hypokalemia
 Incresed Lossed
🠶 Renal
🠶 Extrarenal
 Decreased intake or stores
 Intracellular shift

36. Causes of Hypokalemia
 Increased losses
🠶 Renal –
 RTA(proximal or distal)
 Drugs (diuretics, amphotericin B, aminoglycosides,
corticosteroids),
 Cystic fibrosis
 Mineralocorticoid excess (cushing syndrome, CAH, high
renin(renin secreting tumors, renal artery stenosis)
 Gittelman, Bartter and Liddle syndrome

37. Causes of Hypokalemia
 Increased losses
🠶 Extrarenal –
 Diarrhea/vomiting/nasogastric suction
 Sweating
 Potassium binding resins(sodium polystyrene sulfonate).

38. Causes of Hypokalemia
 Decreased intake or stores
🠶 Potassium poor parenteral nutrition
🠶 Malnutrition, anorexia nervosa
 Intracellular shift
🠶 alkalosis, high insulin state, drugs (ß agonist, theophylline,
barium, hydroxycholoroquine), refeeding syndrome,
hypokalemic periodic paralysis, malignant hyperthermia.

39. Hypokalemia-Treatment
🠶 Determine the underlying cause, whether associated with
hypertension and acidosis or alkalosis.
🠶 Hypertension may be due to primary hyperaldosteronism, renal
artery stenosis, CAH, glucocorticoid, liddle syndrome.
🠶 Relative hypotension and alkalosis suggest diuretic use or
tubular disorder (Bartter/Gittelman syndrome).

40. Hypokalemia-Treatment
🠶 Decrease ongoing losses (stop loop diuretics, replace GI losses). Use K
sparing diuretics, restore i.v volume, correct hypomagnesemia.
🠶 Disease specific therapy , e.g Indomethacin/ACE inhibitors for
Bartter/Gittelman syndrome.
🠶 Correct deficit over 24 hours.
🠶 Replace the deficit : oral route safer. Dose 2-4mEq/kg/day (max-120-
240mEq/day) in 3 or 4 divided doses.

41. Hypokalemia-Treatment
🠶 IV correction is used under strict ECG monitoring.
🠶 For rapid correction in severe hypokalemia (<2.5 or
arrhythmias) 0.5 to 1.0mEq/kg (max-40 mEq ) is given over 1
hour.
🠶 Infusate K should not exceed 40-60 meq/L.

42. Hyperkalemia
🠶 Serum K>5.5mEq/l.
🠶 Factitious or pseudo hyperkalemia: squeezing of extremities during
phlebotomy, sample from limb being infused with K containing fluid or
hemolysed sample.
🠶 Clinical features: nausea vomiting paresthesias, muscle weakness(skeletal,
respiratory), fatigue, ileus, arrhythmia.

43. Hyperkalemia
🠶 ECG changes-

44. Causes of Hyperkalemia
 Decreased losses
 Increased intake
 Extracellular shift
 Cellular breakdown

45. Causes of Hyperkalemia
 Decreased losses:
🠶 Renal failure
🠶 Renal tubular disorder- pseudohypoaldosteronism, urinary tract
obstruction.
🠶 Drugs- ACE inhibitors, ARB, K sparing diuretics, NSAIDS,
heparin.
🠶 Mineralocorticoid deficiency - Addision disease and 21-
hydroxylase deficiency.

46. Causes of Hyperkalemia
 Increased intake
🠶 IV/Oral intake, PRBC transfusion.
 Extracellular shift
🠶 Acidosis, low insulin state, drugs (ß blocker, digitalis,
succinylcholine, fluoride), hyperkalemic periodic paralysis,
malignant hyperthermia.
 Cellular breakdown
🠶 tumor lysis syndrome, crush injury, massive hemolysis.

47. Hyperkalemia- Treatment
🠶 It’s a medical emergency.
🠶 Discontinue K+ containing fluids.
🠶 ECG monitoring.
🠶 If K > 7 or symptomatic with ECG changes- Administer Calcium
gluconate to stabilise myocardium (0.5ml/kg of 10%
Ca.gluconate over 5-10 min).

48. Hyperkalemia- Treatment
🠶 Enhance Cellular uptake of potassium-
 Regular Insulin with glucose i.v (0.3 IU/g glucose over 2 hr).
 NaHCO3 i.v 1-2 meq/kg over 20-30 min.
 ß- agonist (salbutamol/terbutaline nebulized or i.v)

49. Hyperkalemia- Treatment
🠶 Ensure K elimination
 K binding resin (kayexalate oral/per rectal 1g/kg)
 Loop or thiazide diuretic ( if renal functions maintained )
 Hemodialysis
🠶 Correct hypoaldosteronism if present : steroids.

50. Types of fluid therapy
Types of fluid Examples
• Oral fluid
(ORS)
• Glucose based ORS
• Cereal based ORS
• ReSoMal
• IV fluid • Crystalloids (Normal saline,
Ringer’s lactate, 5% Dextrose).
• Colloids (Human Albumin,
Dextran, Haemaccel)

51. Crystalloids Vs Colloids
Features Crystalloids Colloids
1. Content
2. Ability to
cross a semi-
permeable
membrane
1. Na (as a major
osmotically
active particle)
2. Yes
1. High molecular
wt substances
2. Largely Not

52. Common IV fluids and their uses
Types of IV
fluids
indications/Precautions/Complications
1. NS
(0.9% NaCl)
• Uses: Shock, Intravascular resuscitation, AGE, Metabolic
alkalosis, Blood transfusion, Hyponatremia, DKA.
• Use with caution in CCF, edema or hypernatremia.
• For 100 ml blood loss -- Give 400 ml NS.
• Can lead to fluid overload.
2. Ringer’s Lactate
(Hartmann's
solution)
• Dehydration, Burns, GIT fluid loss, Acute blood loss,
Hypovolemia.
• Can cause hyperkalemia in renal patients
• Avoid in liver disease, cerebral edema.
• Incompatible with blood
3. Dextrose (%)
• D5,
• D10,
• D25,
• D50
• Hypernatremia, Dehydration, Hypoglycemia.
• Avoid in resuscitation
• Use cautiously in renal failure patients.
• Incompatible with blood

53. Differences between ORS and
ReSoMal
ORS (New) ReSoMal
1. Constituents
• Na (mmol/L)
• Cl (mmol/L)
• K (mmol/L)
• Citrate (mmol/L)
• Glucose (mmol/L)
2. Other constituents
(Mg, Zn, Cu)
3. Osmolality (mOsmol/L)
4. Specific use
• 75
• 65
• 20
• 10
• 75
• Absent
• 245
• Dehydration
a/w diarrhea
• 45
• 70
• 40
• 07
• 125
• Present
• 300
• Dehydration
+
malnutrition

54. Differences between RL
and NS
Features RL NS
1. Constituents
• Sodium (mmol/L)
• Chloride (mmol/L)
• Glucose (%)
• Other constituents (K, Ca, Lactate)
2. Osmolality (mOsm/L)
3. Fluid overload
4. Risk of metabolic acidosis
5. Contraindications
• 130
• 109
• 1.4
• Present
• 272
• Unlikely
• None
• LA, M. alkalosis,
Renal
insufficiency.
• 154
• 154
• None
• Absent
• 308
• Possible
• Increased
• CCF, edema,
liver
cirrhosis
RL is considered a more physiologically compatible fluid than NS

55. Calculation of Maintenance fluid and
electrolytes requirements

56. Calculation of Maintenance fluid flow rates
Holiday-Segar Method
Example: A 30-kg child would require (100 x 10) + (50 x 10) + (20 x10) = 1,700 ml/day.
Or (4 x10) + (2 x10) + (1 x10) = 70 ml/hr = 70 x 15 = 17.5 drops/min = 70 micro drops/min.
So weight in kg + 40 = Maintenance IV flow rate/hour (for any person weighing > 20 kg)
Weight Ml/kg/day Ml/kg/hr
(“4/2/1 rule”)
Remarks
• 0 – 1 month
NB (< 3.5 kg)
• First 10 kg
(3.5 -10 kg)
100 4 ml/kg/hr
• Next 10 kg
(11-20 kg)
50 2 ml/kg/hr
• > 20 kg 20 1 ml/kg/hr Maximum of
2400 ml daily
Depends upon age of baby ( eg., D1 – 60 ml/kg/day)

57. Factors affecting maintenance fluid requirements
Factors increasing
maintenance fluid
requirements
Factors decreasing
maintenance fluid
requirements
• Fever
(1 C > 38 C  12% fluid)
• Hyperventilation
• Increased environmental
temperature
• Burns
• Ongoing losses
(diarrhea, vomiting, NG tube
aspiration/output)
• Skin: Mist tent, Incubator (PT
baby)
• Lungs: humidified ventilator
• Renal: Oliguria/anuria
• Hypothyroidism
• SIADH

58. Maintenance Electrolyte Requirements
Electrolytes mEq/100 ml of
water/day
mEq/kg/day
• Na • 2-3 • 2 - 3
• K • 1 - 2 • 1 - 2
• Chloride • 2

59. Calculation of
electrolyte deficit
Electrolyte
deficit
Amount to be calculated
(by using a formula)
Remarks
• Na • 0.6 x Body weight x
(Desired concentration –
Current concentration)
• Do not replace Na faster
than 10 – 12 mEq/L/24
hrs.
• K • 0.4 x body weight x
(desired conc. – Current
conc.)
• Maximum rate of infusion
< 0.5 mEq/L
• HCO3 • Base deficit x 0.3 x Body
weight in kg

60. Special circumstances
Term Neonates Burn
• Day 1 : 50 - 60 ml/kg/day
• Day 2 : 70 - 80 ml/kg/day
• Day 3 : 80 -100 ml/kg/day
• Day 4 : 100 – 120 ml/kg/day
• Day 5 : 120 – 150 ml/kg/day
• Parkland formula:
Total fluid requirement in 24 hours
=
• 50 % to be given in 1st 8 hours,
• 50 % to be given in next 16 hours.
4 ml x TBSA (%) x Weight ( kg)

61. Thank you