Practical Oral Rehydration Therapy For Pediatric Dehydration

Here is a link to the excellent article A “NICE solution” to orally rehydrate the dehydrated child aged under 5-years by Dr. Julian M. Sandell, June 8, 2010 (Resource [1] below).

The “NICE solution” article (above) is a wonderful practical review of oral rehydration therapy for pediatric dehydration (and because these posts are just my study notes – I have included most [but not all] of the brief article):

The recently published NICE guideline for the management of gastroenteritis identifies three distinct clinical groups of children:

i. those that are not clinically dehydrated,

ii. those that are dehydrated and

iii. those that are clinically shocked (1),(2).

Reviewing the fluid strategies for each of these three groups (summarised below), it is clear that calculating the fluid volumes required to rehydrate the dehydrated child is the most complex and as a result, these calculations may prove less accessible in routine clinical practice. This process can however be greatly simplified by the application of a simple, clinical observation described below for the management of the dehydrated child…

i. For those children that are not clinically dehydrated, NICE actively encourage oral drinks.

Pediatric Dehydration Guideline (Resource [2] below) reminds us that:

Clinical signs of dehydration give only an approximation of the deficit.

Patients with mild ( <4%) dehydration have no clinical signs. They may have increased thirst.

Returning now to the “NICE Solution” article (Resource [1] below):

ii. For clinically dehydrated children, additional fluids are required to not just maintain their normal body water but also to replace their fluid losses. NICE recommend giving 50 ml/kg of oral rehydration salt solutions (ORS) over 4 hours to replace their fluid losses plus an additional volume of ORS to provide the maintenance fluids required by that child during that 4-hour period of time. In making these calculations, the clinician requires not only a knowledge of the child’s weight but also an appreciation of the formulas used in paediatric practice to calculate a child’s daily maintenance fluid requirements. Performing these calculations is a complex process although this can be greatly simplified by the application of some lateral thinking. If average UK child weights (derived from paediatric growth chart data (3)) were to be used in calculating NICE’s fluid recommendations instead of the child’s true weight, these mathematical calculations can be translated into some simple, practical clinical rules for use by clinicians and carers in their daily practice.

Over the first 4-hour period, estimations reveal that:
     · a 1-year old child requires approximately 30mls every 10             minutes,
     · a 3-year old child requires approximately 40mls every 10             minutes,
     · a 5-year old child requires approximately 50mls every 10             minutes.

These figures (combining both replacement fluid and maintenance fluid calculations in a single figure) could be used to give parents specific, practical rehydration advice, with the aim of encouraging successful oral rehydration and decreasing paediatric inpatient admissions. (Appendix 1 details worked calculations).

[These clinical rules cannot be applied across all geographic regions without ensuring that your population has bodily proportions comparable to UK children and excluding other factors, such as malnutrition].

iii. Clinically shocked children require rapid intravenous fluid resuscitation (20ml/kg of 0.9% Sodium Chloride) and urgent hospital transfer.

In summary, NICE’s guidelines for the dehydrated child can easily be followed by offering these specified volumes of fluid every 10 minutes during the first 4-hour period, without the need to resort to complex calculations. Managing children that are either not dehydrated or clinically shocked is (mathematically!) less complex.

And remember that any child in compensated or uncompensated shock requires an immediate finger stick blood sugar as does any pediatric patient who just looks “mildly unwell.”

But remember that a child can be mildly dehydrated with a normal physical exam as Dr. Fox and others have told us  and parents can help to prevent dehydration by starting oral fluid rehydration as soon as the pediatric patent starts vomitting (Diarrhea and Dehydration):

 It’s about volume!

  • While, it is difficult to truly measure the amount of emesis or diarrhea, most recommend the following:
    • For every episode of emesis, replete 2ml/kg.
    • For every episode of diarrhea, replete 10ml/kg.
  • Use an acceptable Oral Rehydration Solution to help maintain hydration.
    • Fluids with too much sugar (ex, fruit juice) can lead to greater osmotic load in the intestinal lumen, producing more diarrhea.

Summarizing, pediatric dehydration boils down to three cases which usually have to be determined by the history and physical exam.

Children with mild dehydration (< 4%) will have normal vital signs except maybe some increased thirst (Resource [2] below) and are appropriate patients for oral rehydration therapy.

Children with moderate dehydration ( 4 – 6%) are appropriate patients for oral rehydration therapy.

Children with severe dehydration ( </ = 7%) will be in compensated or uncompensated shock and will require immediate parenteral therapy.


(1)  A “NICE solution” to orally rehydrate the dehydrated child aged under 5-years by Dr. Julian M. Sandell, June 8, 2010

(2) Pediatric Dehydration Guideline From the Royal Children’s Hospital of Melbourne

(3) Appendix 1 (link is to a version of Resource (1) that has the Appendix included)

Appendix 1: A Guide to Estimate Fluid Requirements in Diarrhoea and Vomiting caused by Gastroenteritis
(Derived from: NICE Clinical Guideline 84. Diarrhoea and vomiting caused by gastroenteritis: diagnosis, assessment and management in children younger than 5 years).

Age	  UK Average  Fluid requirements   i.e.Child needs 
          Weight(kg)* in first 4hrs (mls)  ....... (mls)
                                           every 10 min
                                           for next 4hrs
Newborn	     3.5	233	             10mls
3 months     6.0	400	             17mls
6 months     7.8	520	             22mls
9 months     8.9	593	             25mls
12 months    9.8	653	             27mls
18 months    11.1	731	             30mls
2 years	     12.2	795	             33mls
3 years	     14.4	923	             38mls
4 years	     16.4	1040	             43mls
5 years	     18.5	1163	             48mls

NICE recommend giving 50 ml/kg of ORS over 4 hours to replace the fluid deficit plus an additional volume of ORS to provide the maintenance fluids required for that 4-hour period of time. The right-hand column performs this calculation, detailing the volume of fluid required every 10 minutes for the first 4-hours of ORS replacement for UK Children of average weight (according to growth chart estimated weight). For smaller or larger children, it is advised to match the fluid volume to that closest to the child’s true weight (Left-hand column).

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