5.4 Some dehydration

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    Patients with some dehydration are not as critically ill as those with severe dehydration, but are at high risk of becoming so. Thus, these patients should be admitted and have their rehydration and clinical evolution supervised.

    5.4.1 Treatment protocol (Plan B)

    Oral rehydration

    The volume of oral rehydration solution (ORS) to be given is 75 ml/kg over 4 hours.



    • An adult (≥ 50 kg) receives 4 litres of ORS over 4 hours, i.e. 1 litre per hour.
    • A 3 year old child (± 14 kg) receives 1 litre (75 ml x 14 kg) of ORS over 4 hours, i.e. 250 ml per hour.


    For volumes to prescribe, see Appendix 5.

    Compensation for on-going losses

    During the rehydration phase, the losses from on-going diarrhoea must be compensated. As soon as the patient can drink:


    Give after each loose stool:

    • 50-100 ml of ORS for children under 2 years
    • 100-200 ml of ORS for children between 2 and 10 years
    • 200-250 ml of ORS for children over 10 years and adults


    The number of cups of ORS consumed must approximate the number of stools produced during the rehydration phase.

    Complementary therapy

    Antibiotic therapy and zinc supplementation (Section 5.3.1 and Appendix 7).

    5.4.2 Patient supervision

    ORS must be provided to the patient in the correct quantity like any other medication during hospitalisation. Rehydrating a patient is not simply prescribing ORS and returning to evaluate after 4 hours.

    During the rehydration phase

    • Every hour:
      • Verify that signs of dehydration are regressing.
      • Note the amount of ORS given and check if hourly consumption is sufficient to complete prescribed quantity within the correct time frame.
      • Note the number of stools and episodes of vomiting.
    • Closer monitoring is required for patients who are not capable of drinking without assistance (e.g. young children), those with abundant, continuing diarrhoea or frequent vomiting or those having trouble drinking (e.g. the elderly who may have altered sensation of thirst).
    • On the other hand, strict surveillance is not necessary for those who are thirsty, capable of drinking without assistance and with little or no vomiting.
    • At any time:
      • If it becomes obvious that oral therapy will fail due to uncontrolled vomiting, switch to IV route and give the amount that would have been given orally, i.e. 75 ml/kg over 4 hours.
      • If signs of severe dehydration appear, switch immediately to the treatment of severe dehydration, starting with the initial bolus (Section 5.3.1).

    End of the rehydration phase

    After the prescribed amount of ORS has been given, reassess the patient’s hydration status.
    If there are no signs of dehydration, the patient can then move onto the maintenance phase.


    However, if a patient was more dehydrated than initially assessed or if on-going losses were not replaced, signs of dehydration may still be present at this point.

    • If signs of some dehydration are still present, repeat the oral rehydration protocol over 4 hours.
    • If signs of severe dehydration are present, start the severe dehydration protocol, including bolus (Section 5.3.1) then, continue the clinical evaluation hourly until the signs of dehydration have regressed and the patient can switch to maintenance therapy.

    5.4.3 Practical tips

    Administration of ORS

    Difficulties in oral rehydration are due to the large volume of ORS to be consumed. Adherence can be poor if the patient is not encouraged by the medical staff. Successful completion of oral rehydration should not be left solely to the patient or attendant.


    Assure that cups of ORS are systematically refilled. Do not simply note the number of cups provided to the patient; ensure that they are being fully consumed. ORS consumption must be observed by medical personnel.


    In children under 2 years, use a teaspoon or a 10-20 ml syringe to administer ORS.


    Vomiting, if not repetitive, is not a contraindication to oral rehydration, but it complicates it.
    Demonstrate how to administer ORS to a child who is vomiting:

    • Children under 2 years: give a teaspoon of ORS every minute
    • Children 2 years and over: give ORS by small sips from a cup every minute

    If the child vomits, wait 10 minutes and try again, taking smaller, less frequent sips (or spoonfuls) every 5 minutes.


    If the patient is thirsty and wants to drink more than prescribed, give more ORS.

    Compensation for on-going losses

    Example: a 3 year old child (± 14 kg) should receive 1 litre of ORS in 4 hours, i.e. 250 ml per hour, according to Treatment Plan B and at least 100 ml of ORS each time he has a stool.


    Time In Out
    1st hour At least 250 ml of ORS 3 liquid stools
    2nd hour

    At least 250 ml of ORS
    + 300 ml (3 x 100 ml) for on-going loss
    In total the child must drink 550 ml within the 2nd hour.

    2 liquid stools
    3rd hour

    At least 250 ml of ORS
    + 200 ml (2 x 100 ml) for on-going loss
    In total the child must drink 450 ml within the 3rd hour.

    2 liquid stools
    4th hour

    At least 250 ml of ORS
    + 200 ml (2 x 100 ml) for on-going loss
    In total the child must drink 450 ml within the 4th hour.

    2 liquid stools
    After 4 hours, the child has no signs of dehydration, s/he switch to Plan A.
    5th hour At least 200 ml to replace on-going loss 2 liquid stools
    Etc. …….. ……..