Intravenous rehydration in paediatric gastroenteritisBMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d7083 (Published 17 November 2011) Cite this as: BMJ 2011;343:d7083
- Alan L Nager, director, emergency and transport medicine
The rehydration of dehydrated children can be seriously challenging. Many factors need to be taken into account when choosing the most appropriate route and method of rehydration, including the setting, equipment, personnel, skill level, volume of patients, and available resources. Fortunately, in the emergency department, all types of rehydration—including oral, nasogastric, and intravenous—should be feasible.
Clinicians have to decide how much fluid to give, the rate of administration, and under what circumstances (level of dehydration) fluid should be given. Larger volumes of fluid given over a shorter period of time are increasingly being recommended.1
In the linked randomised controlled trial (doi:10.1136/bmj.d6976), Freedman and colleagues assessed whether rapid intravenous rehydration improved hydration and clinical outcomes in children with gastroenteritis aged 3 months to 11 years. Patients were randomised to receive 60 ml/kg (rapid) or 20 ml/kg (standard) over one hour. The authors concluded that patients had no clinical benefit from rapid intravenous rehydration over standard treatment and that its use should be reconsidered.2
All studies should be rational, prudent, “pragmatic,” and scientifically based. Freedman and colleagues justify their study because previous research has highlighted safety concerns with intravenous hydration, especially in haemodynamically stable children,3 and because previous studies were mainly descriptive and provided only inconclusive evidence about its safety or efficacy.4 Although Freedman and colleagues’ study poses important and measurable questions, it is not medically justified to give 20 ml/kg of intravenous fluid to mild to moderately dehydrated patients when clinicians and researchers advocate oral rehydration therapy.5 Moreover, children in the rapid rehydration group were given 60 ml/kg of fluid, the same amount given typically to patients with severe dehydration, even though these children were not severely dehydrated. Although the study’s design is generally acceptable, the assessment of dehydration is questionable. Reliance on the eight point clinical dehydration scale used in previous research is inappropriate and led to inaccurate assessments. This scale was validated as a way of determining whether infants and toddlers with gastroenteritis needed fluid, not to assess quantities needed or best rates of administration.6 7 8
The estimation of dehydration was inconsistent, and this resulted in four patients in the standard group and two in the rapid group developing oedema. Furthermore, the authors admit that the scale was not perfect given that their standard rehydration protocol was sufficient to rehydrate many of the children and that some children with mild dehydration were probably enrolled.2
In addition, several of the findings are illogical given the supposed balanced enrolment among study subjects in both groups, despite the wide variation in amounts of fluid administered. For instance, the median time to discharge was longer in the rapid rehydration group; prolonged treatment occurred in 52% of the rapid rehydration group and 43% of the standard rehydration group; nearly twice as many children in the rapid rehydration group were admitted to hospital at the first visit; additional fluid boluses were given to 14% of the standard rehydration group and 10% of the rapid rehydration group; and time to resolution of dehydration was similar (two hours from the start of treatment) in both study groups.2
Studies should be comparable and rational. Freedman and colleagues raise concerns about rapid intravenous rehydration, citing a randomised trial of bolus resuscitation in febrile African children with severe infection, noting that the fluid had to be stopped early owing to increased mortality.9 However, the study population is hardly comparable to the current study, in which participants were afebrile Canadian children with gastroenteritis. The authors are also critical of a previous study of moderately dehydrated patients in which one group received 50 ml/kg over one hour and another received 50 ml/kg over three hours.10 Fluid estimates were based on 11 clinical parameters supplemented by laboratory testing and clinical assessments. No patients had oedema or evidence of over-hydration, and all were discharged home. This study also reflects the recommendations of previous researchers who have suggested that shorter and faster fluid administration should be used in the appropriate clinical setting.11 Nonetheless, Freedman and colleagues have made an appropriate attempt to question the utility, safety, and efficacy of rehydration using a rapid high volume method.
Assessment of dehydration has been a longstanding challenge among clinicians. Investigators have developed clinical scores and predictors of dehydration,12 but these merely help clinicians by outlining the most sensitive factors for assessing dehydration and do not stipulate volume and rates of fluid administration. Therefore, rehydration and treatment are most often determined by considering, among other factors, a combination of history (such as number of episodes of vomiting and diarrhoea, travel history), clinical findings, previous and current weight, laboratory test results (if the patient has severe dehydration and chronic illness), and fluid input and output.
Only a handful of studies of rapid rehydration have been published, none of which are consistent with each other, but none has shown that large volume, rapidly administered fluid is unsafe. Future studies should therefore have strict assessment criteria, a uniform population with similar levels of dehydration, appropriate monitoring parameters, and admission and discharge criteria. Furthermore, large multicentre studies should be conducted to assess new dehydration treatment schemes and be powered for safety considerations. As rehydration treatment strategies evolve, clinicians should consider alternative treatments, such as large volume, rapidly administered fluid. However, as with most new clinical regimens, it is important for clinicians to understand that a few studies with a small number of participants should not necessarily change practice—healthy scepticism is essential.
Cite this as: BMJ 2011;343:d7083
Competing interests: The author has completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Provenance and peer review: Commissioned; not externally peer reviewed.