Page 90 - 15Diarrhoeaandvomiting

Fluid management

Evidence summary

There were no studies that provided direct evidence on the effectiveness of various oral fluid
regimens in terms of the route of administration, frequency of administration or volume of fluid to be
used. However, the procedures used in studies suggest that children with gastroenteritis and severe
dehydration can be successfully rehydrated with ORT after an initial rehydration with IVT. After an
initial rehydration with IVT, ORT was usually introduced within 2–4 hours of starting rehydration.

GDG translation from evidence to recommendation
There was no evidence to support recommendations on how much fluid should be given, and
over what time frame, when treating a dehydrated child. The WHO recommends rehydration
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over a period of 4 hours. The GDG agreed that clinical experience showed this to be generally
possible. It was considered important to achieve rehydration as quickly as possible, but more
rapid rehydration might be associated with an increased risk of vomiting.
The traditional approach to oral rehydration has been to offer ORS solution in small quantities at
frequent intervals. That seemed appropriate advice and the GDG agreed that it would improve
tolerance.
Given that precise determination of dehydration severity is not possible, the exact volume of fluid
required for rehydration cannot be calculated accurately at the outset. At the mildest end of the
spectrum, dehydration may be clinically undetectable. It is likely that clinical signs of dehydration
first become apparent in patients with about 3–5% weight loss. Children who are at the most
severe end of the spectrum may have lost 10% or more of their body weight. The GDG therefore
considered that a reasonable approach in a child presenting with clinical manifestations of
dehydration was to assume 5% dehydration at the outset. Based on that assumption, rehydration
should be attempted by giving 50 ml/kg over the initial 4 hour rehydration period. In some cases,
this may be somewhat more than is required, but that will be of no clinical consequence. In
other more severely dehydrated children, 50 ml/kg may be insufficient. It would therefore be
important to regularly reassess the child’s state of hydration and, when necessary, to increase
the final volume of replacement fluid administered (see worked example in Tables 5.2 and 5.3).
Children with red flag symptoms or signs (see Table 4.6) would require frequent reassessment
during rehydration, with adjustment of the deficit replacement depending on that assessment.
The use of a nasogastric tube to deliver ORS solution is common but not universal practice. It
may allow oral rehydration of children who will not drink ORS solution. If children vomit ORS
solution persistently, continuous infusion through a nasogastric tube may improve tolerance but
there are no studies on this method of administrating ORT. Placement of a nasogastric tube may
be somewhat unpleasant or distressing for children. There are possible complications associated
with nasogastric feeding. These concerns needed to be balanced against the alternative of IVT,
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Table 5.2 Worked example of an oral rehydration strategy in a 12-month-old child weighing 10 kg

Strategy Volume Rate
Fluid deficit for replacement over 4 hours 500 ml 125 ml/hour
Maintenance fluids over 24 hours a 1000 ml 40 ml/hour
Total volume for first 4 hours 660 ml 165 ml/hour
Aliquot volume if administered at 10 minute intervals 27.5 ml/10 minutes
a Maintenance fluids 95

Table 5.3 Maintenance fluid volume requirements based on body weight

Weight (kg) Volume per day Volume per hour
0–10 100 ml/kg 4 ml/kg per hour
10–20 1000 ml + 50 ml/kg for each kg > 10 40 ml + 2 ml/(kg > 10)
20+ 1500 ml + 20 ml/kg for each kg > 20 60 ml + 1 ml/(kg > 20)

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