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5 Fluid management

Introduction
Dehydration is the major complication associated with gastroenteritis. Ideally it should be
prevented through appropriate fluid management. Once clinically significant dehydration
is present, effective and safe strategies for rehydration are required. Additionally, following
rehydration there may be a risk of recurrence of dehydration and appropriate fluid management
may reduce the likelihood of that event. In this chapter, primary and secondary prevention of
dehydration and the fluid management of children with established dehydration are considered.
One of the great medical advances of the 20th century was the introduction of oral rehydration
therapy (ORT). ORT refers to the restitution of water and electrolyte deficits in dehydrated patients
using an oral rehydration salt (ORS) solution. The term ‘ORS solution’ is applied to special fluid
formulations containing as essential ingredients an organic solute (for example, a carbohydrate
or amino acid) and sodium chloride. Such solutes are subject to active intestinal co-transport
and thereby enhance salt and water absorption. Typically, ORS solution contains glucose and
sodium chloride in specified concentrations. This chapter considers the use of ORT in the fluid
management of children with gastroenteritis.

5.1 Primary prevention of dehydration

Clinical questions
Can oral fluid supplementation prevent dehydration? What oral fluid strategies are most
effective in preventing dehydration?

A search was undertaken to identify published research on the prevention of dehydration in
children with diarrhoea and/or vomiting. Although it may appear self-evident that supplemental
fluids might prevent dehydration, the effectiveness of this strategy could not be assumed.
Moreover, various strategies for fluid supplementation could be considered.

Evidence overview
After primary screening of 206 articles and abstracts identified from the literature search, 20
articles were retrieved. Most of these studies had in fact assessed the effectiveness of oral fluids
in the treatment of gastroenteritis and dehydration rather than in the prevention of dehydration.
Only one prevention study was identified. In that study, continued breastfeeding and use of ORS
solution at home were evaluated as potential strategies for preventing dehydration.
In a case–control study from Bangladesh, children aged between 1 and 35 months were selected
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for study inclusion if they had watery diarrhoea for 6 days or less at first presentation and had
been breastfeeding up to the time of onset of diarrhoea. All were assessed for dehydration and
were classified as ‘cases’ (with moderate to severe dehydration if there was a definite decrease in
skin elasticity and presence of one or more of following signs: sunken eyes, failure to urinate for
6 hours, sunken anterior fontanelle, rapid and weak pulse) or as ‘controls’ (with no dehydration or
mild dehydration if they did not fulfil those clinical criteria). Home ORT use was defined as giving
either pre-packaged ORS solution or home-made salt and sugar solution. Information on socio-
economic and demographic characteristics, medical history and fluid/feeding interventions at
home was collected using a field-tested structured questionnaire administered by an interviewer.
Cases and controls were recruited from the same reporting area. Observer bias was reduced
by blinding the interviewers to the hypothesis being tested and by blinding both mothers and
interviewer to the case and control allocation. After analysing the association of each factor
of interest with dehydration and identifying various confounding variables, logistic regression
analysis was conducted to identify factors independently associated with dehydration. [EL = 2+]

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