Dehydration and rehydration in childhood

1. DEHYDRATION IN
PEDIATRICS

2. DEHYDRATION OVERVIEW
• Water is an essential element of the body. From 80% of the body's weight of a
newborn to 60% in adults’ body weight is made up of water. TBW is divided
between two main compartments: intracellular fluid (ICF) and extracellular fluid
(ECF). The ECF is further divided into the plasma water and the interstitial fluid.
• The volume of plasma water can be altered by a variety of pathologic
conditions, including dehydration, anemia, polycythemia, heart failure,
abnormal plasma osmolality, and hypoalbuminemia.
• The interstitial fluid, normally about 15% of body weight, can increase
dramatically in diseases associated with edema such as heart failure, liver
failure, nephrotic syndrome, and other causes of hypoalbuminemia.
• Dehydration occurs when the amount of water leaving the body is greater than
the amount being taken in.
• The high fat content in overweight children leads to decrease in TBW as a
percentage of body weight.
• During dehydration the TBW decreases and, thus, is a smaller percentage of
body weight

3. Total body water according to age

4. Electrolytes

5. Dehydration is a condition that can occur with excess loss of
water and other body fluids. Dehydration results from decreased
intake (due to mouth ulcers, stomatitis, pharyngitis), increased
output (renal, gastrointestinal or insensible losses, fever), a shift of
fluid (e.g. ascites, effusions), or capillary leak of fluid (e.g. burns and
sepsis).
Congenital adrenal hyperplasia - hypoglycemia, hypotension,
hyperkaliemia, and hyponatremia.
Pyloric stenosis - often associated with poor intake, vomiting.
Cystic fibrosis - excessive sodium and chloride losses in sweat.
Diabetes insipidus - excessive output of very dilute urine.
Thyrotoxicosis - increased insensible losses and diarrhea.
Definition

6. PATHOPHYSIOLOGY OF
DEHYDRATION
Decreased Intravascular volume 
Decreased Venous return
Decreased Ventricular filling
Decreased Stroke volume
Decreased Cardiac output
Inadequate tissue perfusion

7. • Hyponatremic: primarily a loss of electrolytes,
particularly sodium < 135 mmol/l
• Hypernatremic: primarily a loss of water,
Na > 158 mmol/l
• Isonatremic: equal loss of water and electrolytes sodium
135-154 mmol/l
TYPES OF DEHYDRATION BASED ON
TYPE OF FLUID LOSS

8. Mild :
when the total fluid loss reaches 5% or less.
Moderate :
when the total fluid loss reaches 5-10%.
Severe :
when the total fluid loss reaches more than 10%.

9. Mild dehydration
• Thirst
• Consciousness
• Less than 5% of body Weight is lost.

10. Moderate dehydration
• Dry skin and mucous membranes
• Thirst
• Decreased urine output
• Crying baby with tears
• Muscle weakness
• Drowsiness
• Light headache
• Sunken fontanels
• Decreased BP
• Increased Pulse rate (tachycardia)
• 5 to 10 % of body Weight is lost
• Capillary refill
• Shallow rapid RR

15. • Extreme thirst
• Very dry mouth, skin and mucous membranes
• Sunken eyes
• Sunken fontanels
• No tears
• Dry skin that lacks elasticity and slowly “bounces back” when
pinched into a fold
• Rapid heartbeat
• Rapid and shallow breath
• Unconsciousness
• More than 10% of body Weight is loss
• Delay in Capillary refill for more than 2 seconds
Severe dehydration

16. Mild Moderate Severe
Weight loss Up to 5% 6-10% More than 10%
Appearance Active, alert Irritable, alert, thirsty Lethargic, looks sick
Capillary filling
(compared to your
own)
Normal Slightly delayed Delayed
Pulse Normal Fast, low volume Very fast, thready
Respiration Normal Fast Fast and deep
Blood pressure Normal Normal or low
Orthostatic hypotension
Very low
Mucous memb. Moist Dry Parched
Tears Present Less than expected Absent
Eyes Normal Normal Sunken
Pinched skin Springs back Tents briefly Prolonged tenting
Fontanel (infant
sitting)
Normal Sunken slightly Sunken significantly
Urine flow Normal Reduced Severely reduced

17. POSSIBLE
COMPLICATIONS
• Permanent brain damage
• Seizures
• Hypernatremia
• Hyponatremia
• Hypovolemic shock
• Kidney failure
• Coma and death

18. TREATMENT
• Dehydration treatment depends on age, weight, severity of
dehydration and its cause.
 Oral rehydration solution (ORS) for mild and moderate
dehydration
 IV fluid replacement (for severe dehydration)
 Treating the cause of dehydration

19. TREATMENT OF MILD AND MODERATE
DEHYDRATION
 Oral rehydration solution (ORS)
is a simple treatment for dehydration
According to WHO formula:
Glucose:13.5-20 g, NaCl: (2.6) 3.5 g,
KCl:1.5 g, Na citrate: 2.9 g,
Water: 1 liter
Contraindications for ORS:
1. Severe dehydration.
2. Unconsciousness.
3. Frequent vomiting attacks.
 Continue breastfeeding.

21. Daily Maintenance Fluid Requirements
• Calculate child’s weight in kg.
• Allow 100 ml/kg for the first 10 kg body weight.
• Allow 50 ml/kg for the second 10 kg body weight.
• Allow 20 ml/kg for the remaining body weight.
DAILY MAINTENANCE FLUID
REQUIREMENTS

22. CALCULATING REPLACEMENT
• Deficit in ml = wt (kg) x % dehydrated x 10 (ideally the pre-
dehydration weight should be used).
14 kg child which is 5% dehydrated
has a deficit of 14 x 5 x 10 = 700 ml.

23. INTRAVENOUS REHYDRATION
INDICATIONS
• A. Diarrhea - Severe dehydration (> 10% of BW loss in infants)
- Diarrhea, accompanied by severe uncontrolled vomiting
- Inability to comply with oral fluids
• B. Other indications include Hemorrhage, Shock, Electrolyte
disturbances
• Supplying fluids and food for patients who are unable to maintain oral
intake.

24. INTRAVENOUS REHYDRATION
• Correction of existing fluid deficit
• Replacement of ongoing losses
• Providing the normal daily requirement
Degree of dehydration (% of body weight) Existing fluid deficit
Mild (No signs of dehydration) <5% < 50ml/Kg
Moderate (Some dehydration) 5-10% 50-100ml/Kg
Severe (Severe dehydration) >10% > 100ml/Kg
Example: existing loss of a 5kg weighting boy presented to you with “Some dehydration” is
250 to 500 ml.
Deficit of Sodium – 6-10 mmol/100ml
Deficit of Potassium – 4-6 mmol/100ml
Max. concentration of Potassium in the infusion – 40 mmol/l or 3 mmol/kg/24h
15 mmols of Sodium in 100 ml Serum physiologicum 0,9%
20 mmols of Potassium in 10 ml Potassium Cloride 15%

25. DAILY REQUIREMENTS
Body Weight Fluid per Day Sodium Potassium
0-10 kg 100 mL/kg 3 2
11-20 kg 50 mL/kg for each kg > 10 kg 2 2
> 20 kg 20 mL/kg for each kg > 20 kg 1 1
The maximum total fluid per day is normally 2,400 mL.
The maximum fluid rate is normally 100 mL/hr.
0-10 kg: 4 mL/kg/h
10-20 kg: 40 mL/h + 2 mL/kg/h
>20 kg: 60 mL/h + 1 mL/kg/h

26. EXAMPLE
H2O Na/Cl Ser. Phys.
Existing deficit 560 45 300
Daily needs 800 24 170
Ongoing losses 100 8 50
Weight – 8kg
Moderate dehydration – 7%
BE – (-11)
H2O Na/Cl Ser. Phys.
Existing deficit Weight x dehydration
degree x10
Deficit of water/100 x
6-10 mmol/100ml
(Deficit of sodium/15)
x 100
Daily needs Acc. to the table on previous slide
Ongoing losses App. 2% of BW, max 200ml or measured
Correction of acidosis according
to Astrup formula:
NaHCO3 8,4%  BE x 0,3 x kg

27. H2O Na/Cl Ser. Phys.
Existing deficit 560 45 300
Daily needs 800 24 170
Ongoing losses 100 8 50
Total 1460 77 520
0-2h
½ existing deficit
1st – 150ml Ser. Phys.
280ml 2nd – 130ml Sol. Gluc. 5%
3-8h
½ ex.def.+1/3 daily needs
3rd – 210ml Ser. Phys.
550ml 4th – 340ml Sol. Gluc 5%
9-24h
2/3 daily needs + ongoing losses
5th – 160ml Ser. Phys.
630ml 6th – 470ml Sol. Gluc. 5%

28. Thank you for your attention!

29. Weight – 10kg, Moderate dehydration – 10%, BE – (-8)  0,3x10x/-8/24
H2O Na/Cl Ser. Phys.
Existing deficit 1000 80 530
Daily needs 1000 30 200
Ongoing losses 200 16 100
Total 2200 126 830
0-2h
½ existing deficit
1st – 270 ml Ser. Phys.
500ml 2nd – 230 ml Sol. Gluc. 5%
3-8h
½ ex.def.+1/3 daily needs
3rd – 330 ml Ser. Phys.
830ml 4th – 500 ml Sol. Gluc 5%
9-24h
2/3 daily needs + ongoing losses
5th – 230 ml Ser. Phys.
870ml 6th – 640 ml Sol. Gluc. 5%
More examples:

30. Weight – 12kg, Moderate dehydration – 8%, BE – (-7)  0,3x12x/-7/25,2
H2O Na/Cl Ser. Phys.
Existing deficit 960 77 510
Daily needs 1100 34 200
Ongoing losses 200 16 100
Total 2260 127 810
0-2h
½ existing deficit
1st – 250 ml Ser. Phys.
480 ml 2nd – 230 ml Sol. Gluc. 5%
3-8h
½ ex.def.+1/3 daily needs
3rd – 330 ml Ser. Phys.
840 ml 4th – 510 ml Sol. Gluc 5%
9-24h
2/3 daily needs + ongoing losses
5th – 230 ml Ser. Phys.
940 ml 6th – 710 ml Sol. Gluc. 5%

31. Weight – 8kg, Mild dehydration – 4%, BE – (-6)  0,3x8x/-6/14,4
H2O Na/Cl Ser. Phys.
Existing deficit 320 24
Daily needs 800
Ongoing losses 160
Total 1360
0-2h
½ existing deficit
1st – ml Ser. Phys.
ml 2nd – ml Sol. Gluc. 5%
3-8h
½ ex.def.+1/3 daily needs
3rd – ml Ser. Phys.
ml 4th – ml Sol. Gluc 5%
9-24h
2/3 daily needs + ongoing losses
5th – ml Ser. Phys.
ml 6th – ml Sol. Gluc. 5%

32. Weight – 11kg, Moderate dehydration – 7%, BE – (-8)  0,3x11x/-7/
H2O Na/Cl Ser. Phys.
Existing deficit
Daily needs
Ongoing losses
Total
0-2h
½ existing deficit
1st – ml Ser. Phys.
ml 2nd – ml Sol. Gluc. 5%
3-8h
½ ex.def.+1/3 daily needs
3rd – ml Ser. Phys.
ml 4th – ml Sol. Gluc 5%
9-24h
2/3 daily needs + ongoing losses
5th – ml Ser. Phys.
ml 6th – ml Sol. Gluc. 5%