No

1. Fluids & Electrolytes
Pediatric Emergency Medicine
Boston Medical Center
Boston University School of Medicine

2. Objectives
 To discuss:
 Maintenance Fluids and Electrolyte Requirements
 Types of Dehydration
 Management of Dehydration
 Electrolyte Abnormalities

3. Composition of Body
Compartments
 Total Body Water (TBW)= 50-75% of Total Body
Mass
 TBW = Intracellular Fluid (ICF) + Extracellular Fluid (ECF)
 ICF = 2/3 of TBW
 ECF = 1/3 of TBW -- 25% of body weight
 ECF = Plasma (intravascular) + Interstitial fluid

4. Body Water Compartments
Related to Age
0
10
20
30
40
50
60
70
80
0 years 1 year 10 years 20 years
TBW
ICF
ECF

5. Regulation of Body Fluids and
Electrolytes
 Mechanism to Regulate ECF volume
 Anti-Diuretic Hormone (ADH)
• Kidney = Increase water reabsorption
• ADH secretion is regulated by tonicity of body
fluids
 Thirst
• Not physiological stimulated until plasma
osmolality is >290

6. Regulation of Body Fluids and
Electrolytes
 Aldosterone
• Released from the adrenal cortex
– Decrease circulating volume
– Stimulation by Renin-Angiotensin Aldosterone axis
– Increase plasma K
• Enhanced renal reabsorption of Na in
exchange for K (>Na = expansion of ECF)
 Atrial Natriuretic Factor
• Secreated by the cardiac atrium in response to
atrial dilatation (regulates blood volume)
• Inhibits Renin secretion
• Increase GFR and Na excretion

7. Daily Maintenance
Requirements

8. 4cc, 2cc, 1cc rule
 4 cc for the first 10 kg
 2 cc for the next 10 kg
 1 cc for each kg after
 Example:
• 27 kg child
– 4 cc for the first 10 kg = 40cc
– 2 cc for the next 10 kg = 20cc
– 1 cc for each kg after = 7 cc
67 cc/hr

9. Maintenance Requirements
 Maintenance Fluids: weight dependent
& age dependent:
 (NS =0.9% Saline =154 meq Na/liter)
 age >2 -3 years: D5 0.5 NS + 20 meq
KCl/liter
 Up to age 2-3 years: D5 0.2 NS + 20 meq
KCl/liter
• D5 = 50 gm/liter = 5 g/dl
• Newborns often require D10 = 100 gm/liter = 10
gm/dl

10. Dehydration
 Epidemiology:
 One of the most common medical problems
 In the U.S. - 10% of all pediatric admissions
 Worldwide, over 3 million children under 5
years die from dehydration

11. Estimation of Dehydration
Mild Moderate Severe
Weight Loss 3-5% 6-9% >10%
Blood pressure Normal Orthostatic Shock
Pulse Normal Increase Tachycardic
Behavior Normal Irritable Lethargic
Membranes Moist Dry Parched
Tears Present Decrease Absent
Cap. Refill 2 seconds 2-4 seconds >4 seconds
Urine SG >1.020 >1.030 Oliguria

12. Dehydration
 Classification
 Isotonic
• Serum Sodium 130-150 mEq
 Hypotonic
• Serum Sodium < 130 mEq
 Hypertonic
• Serum Sodium >150 mEq

13. Management of Dehydration
 General Principles:
 Supply Maintenance Requirements
 Correct volume and electrolyte deficit
 Replace ongoing abnormal losses

14. Management of Dehydration
 Oral Rehydration:
 Effective for mild and some moderate
dehydrations
 Child may be able to tolerate PO intake
 Small aliquots as tolerated
• Mild: 50 cc/kg over 4 hours
• Moderate: 100 cc/kg over 4 hours
 2 types of oral solution
• Maintenance
• Rehydration

15. Commercial Oral Solutions
Na mEq/L K mEq/L Cl mEq/L Base CHO %
Maintenance
 Reosol 50 20 50 Citrate Glucose 2
 Ricelyte 50 25 45 Citrate Rice syrup 3
 Pedialyte 45 20 35 Citrate Glucose 2.5
Rehydration
 Rehydralyte 75 20 65 Citrate Glucose 2.5
 W.H.O
For cholera use
90 20 80 HCO3 Glucose 2

16. Management of Dehydration:
IV
 Replacement of Fluid Deficit Based on %
Dehydration:
 Example: 5 kg child who is 6% dehydrated: 5 x
60cc/kg
• fluid deficit (cc) = wt x % dehydration
• fluid deficit (cc) = wt in kg (1000cc/kg) x (1/100)
estimate of dehydration
• fluid deficit (cc) = wt x 10 x estimate of dehydration
• fluid deficit (cc) = 5 x 10 x 6
• fluid deficit (cc) = 300 cc

17. Management of Dehydration:
IV
 Initial: NS or LR 20 cc/kg Bolus in first hour
 Then Remainder of Deficit
• In previous example: total fluid deficit = 300cc
for 5 kg child who is 6% dehydrated = 60cc/kg
• Replacement:
– first hour: 20 cc/kg = 20 x 5 = 100 cc
– replace the rest: 40 cc/kg or 300 - 100 = 200 cc
– The type of fluid used and the rate of infusion
depends on the age and Na status of the patient:
» for isonatremic dehydration: correct deficits of
next 7 hours
» 200cc over 7 hours = 28 cc/hr

18. Hyponatremia
 Predisposing Factors
 Diabetes mellitus (hyperglycemia)
 Cystic fibrosis
 CNS disorders ( SIADH)
 Gastroenteritis
 Excessive water intake (formula dilution)
 Diuretics (thiazides and furosemide)
 Renal disease

19. Hyponatremia
 Hyponatremic Dehydration
 Hypovolemic Hyponatremic Dehydration
• High urine output and Na excretion
• Increase in atrial natriuretic factor
 Euvolemic Hyponatremic Dehydration
• ADH mediated water retention
 Hypervolemic Hyponatremic Dehydration
• Edematous disorder (nephrotic syndrome, CHF,
cirrhosis)
• Water intoxication

20. Hyponatremia
 Acute Hyponatremia (<24 hours)
 Early Onset (Serum Sodium <125 meq/L)
• Nausea
• Vomiting
• Headache
 Later or Severe (Serum Sodium <120 meq/L)
• Seizure
• Coma
• Respiratory arrest

21. Hyponatremia
 Chronic Hyponatremia (>48 hours)
 Lethargy
 Confusion
 Muscle cramps
 Neurologic Impairment

22. Hyponatremia
 Management
 Na Deficit:
• Na Deficit = (Na Desired - Na observed) x 0.6
x body weight(kg)
 Replace half in first 8 hours and the rest in the
following 16 hours
 Rise in serum Na should not exceed 2 mEq/L/h to
prevent Central Pontine Myelinolysis (? Existence
in children)
 In cases of severe hyponatremia (<120 mEq) with
CNS symptoms:
• 3% NaCl 3-5 ml/kg IV push for hyponatremia
induced seizures
– 6 ml/kg of NaCl will raise serum Na by 5 mEq/L

23. Hypernatremia
 Hypernatremia leads to hypertonicity
 Increase secretion of ADH
 Increase thirst
 Patients at risk
 Inability to secrete or respond to ADH
 No access to water

24. Hypernatremia
 Etiology
 Pure water depletion
• Diabetes insipidus (Central or Nephrogenic)
 Sodium excess
• Salt poisoning (PO or IV)
 Water depletion exceeding Na depletion
• Diarrhea, vomiting, decrease fluid intake
 Pharmacologic agents
• Lithium, Cyclophosphamide, Cisplatin

25. Hypernatremia
 Signs and symptoms
 Disturbances of consciousness
• Lethargy or Confusion
 Neuromuscular Irritability
• Muscle twitching, hyperreflexia
 Convulsions
 Hyperthermia
• Skin may feel thick or doughy

26. Hypernatremia
 Management
 Normal Saline or Ringer lactate to restore volume
 Hypotonic solution (D5 1/4 NS) to correct calculated
deficit over 48 hours
• Water Deficit
– Normal body H20 - Current body H20
• Current body water
– 0.6 x body weight (kg) x Normal Na/Observed Na
• Normal Body water
– 0.6 x body weight (kg)
 Decrease Na concentration at a rate of 0.5 mEq/hr
or ~ 10 mEq/day: Faster correction can result in
Cerebral Edema

27. Potassium
 Most abundant intracellular cation
 Normal serum values 3.5-5.5 mEq
 Abnormalities of serum K are potentially life-
threatening due to effect in cardiac function

28. Hypokalemia
 Diagnosis
 Symptoms
• Arrhythmias
• Neuromuscular excitability (hyporreflexia, paralysis)
• Gastrointestinal (decreased peristalsis or ileus)
 Serum K < 3mEq/L
 ECG:
• Flat T waves
• Short P-R interval and QRS
• U waves

29. Hypokalemia
Nutritional GI Loss Renal Loss Endocrine
Poor intake Diarrhea Renal tubular acidosis Insulin therapy
IVF low in K Vomiting Chronic renal disease Glucose therapy
Anorexia Malabsorbtion Fanconi's syndrome DKA
Intestinal fistula Gentamicin, Hyperaldosteronism
Laxatives Amphotericin Adrenal adenomas
Enemas Diuretics Mineralocorticoids
Bartter's syndrome
Bartter’s syndrome: Hypereninemia and hyperaldosteronism

30. Hypokalemia
 Management:
 Cardiac Arrhythmias or Muscle Weakness
• KCl IV (cardiac monitor)
 PO K - Depend of etiology
• Hypophoshatemia = KPO4
• Metabolic acidosis = KCl
• Renal tubular acidosis = K citrate

31. Hyperkalemia
 Differential Diagnosis
 Pseudohyperkalemia - from blood hemolysis
 Metabolic Acidosis
 Chronic Renal Failure
 Congenital Adrenal Hyperplasia
• Females = Usually Dx at birth - Ambiguous
Genitalia
• Males = Dehydration, hyponatremia, hyperkalemia
 Medications
• ACE inhibitors and NSAID’s

32. Hyperkalemia
 Diagnosis:
 Symptoms
• Cardiac Arrhythmias
• Paresthesias
• Muscle weakness or paralysis
 ECG
• Peaked T waves
• Short QT interval (K>6 mEq)
• Depressed ST segment
• Wide QRS (K>8 mEq)

33. Hyperkalemia
 Management
 Close cardiac monitoring
 Life -threatening hyperkalmia
• Intravenous Calcium - rapid onset, duration< 30 min
• NaHCO3 or glucose and insulin
 Ion exchange resins
• Sodium polystyrene sulfonate (Kayexelate)
– PO or Enema
 Hemodyalisis