Paediatric Acute care Guidelines PMH Emergency Department

Gastroenteritis is vomiting or diarrhoea or both caused by viruses in 70% of cases, bacteria in 20% and protozoa in 10%


  • Vomiting may occur before the onset of diarrhoea. However, vomiting in isolation may be due to a wide range of other potentially serious conditions.
  • Concerning features suggesting an alternate diagnosis are significant abdominal pain, co-morbidities, < 6 mths old, high fever, prolonged symptoms, or signs suggesting a surgical cause.
  • In infants, vomiting must be distinguished from the normal phenomenon of regurgitation.
  • Oral/NGT rehydration is preferable to intravenous except in severe cases.

Risk factors

  • Attending childcare
  • Recent travel overseas



  • Evaluation of the severity of dehydration is difficult even by a senior doctor
  • Non dehydrated patients do not need a fluid trial in the ED


Clinical Severity of Dehydration

No or mild dehydration
(< 3% weight loss)
Moderate dehydration
(4 – 6% weight loss)
Severe dehydration
(7 – 10% weight loss)
  • No physical signs


  • Thirst
  • Dry mucous membranes
  • Reduced urine output
  • Dry mucous membranes
  • Reduced urine output
  • Tachycardia
  • Sunken eyes (and minimal or no tears
  • Diminished skin turgor
  • Altered neurological status (drowsiness, irritability)

Increasingly marked signs from the moderate group, plus:

  • Decreased peripheral perfusion (cool, mottled, pale peripheries; capillary refill time > 2 sec)
  • Anuria
  • Hypotension
  • Circulatory collapse



  • No investigations are required in mild cases of gastroenteritis
  • Stool specimen is required for patients with bloody stool, prolonged diarrhoea and recent travel overseas
  • FBC, U&E and VBG should be done if inserting an intravenous cannula to commence intravenous fluids

Differential diagnoses


  • Non dehydrated children can be discharged after reassurance, education and a health facts sheet to go home.
  • Non dehydrated children can eat as tolerated, but should avoid sweet and fatty foods.
  • Continue breastfeeding but add extra fluids as required.
  • Ondanestron may be used in the Emergency Department before a fluid trial but not as a discharge medication. It can make the diarrhoea last longer.
  • In moderately dehydrated childen oral/nasogastric rehydration is preferrable to intravenous as it corrects acidosis quicker, the diarrhoea and vomiting settle faster and appetite returns sooner.
  • Severe dehydration needs admission for intravenous rehydration and electrolytes need to be checked.

Further management

Mild Dehydration
    • Oral fluids (1mL/kg every 10 minutes of oral rehydration solution) can be provided while awaiting  medical assessment
    • Use ED Oral Fluid Trial Form
    • Fluids high in sugar (such as cola, apple juice, and sports drinks, which contain ≤ 20 mmol/l sodium and have a high osmolality of 350-750 mOsm/l) may exacerbate diarrhoea and should be avoided
    • Solids and milk can be continued if the child is interested and not dehydrated
    • Most mildly dehydrated children (<3%) can be discharged
    • On Discharge:  Ensure the carers are discharged with appropriate education on gastroenteritis, such as how to provide fluid and signs of dehydration
Moderate Dehydration
    • Consider Ondansetron (0.1 – 0.2mg/kg PO or IV)
    • Oral fluid trial 1mL/kg (maximum 20 mL) every 10 minutes of oral rehydration solution (ORS) for 1-2 hours
    • Use ED Oral Fluid Trial Form
    • Fluids high in sugar (such as cola, apple juice, and sports drinks, which contain ≤ 20 mmol/l sodium and have a high osmolality of 350-750 mOsm/l) may exacerbate diarrhoea and should be avoided
    • Solids and milk can be continued if the child is interested and not dehydrated otherwise wait until rehydrated


If the child fails oral fluid trial:

    • Nasogastric tube (NGT) rapid rehydration: 50mL/kg over 4 hours with oral rehydration solution (ORS). This corrects for 5% dehydration.
    • Admit to the Emergency Department Observation Ward (4E)
    • If the child vomits reduce the rapid rehydration rate to 50mL/kg over 6 hours


If the child fails NGT rapid rehydration (> 2 vomits):

    • Admit to General Paediatric Team
    • Hourly observations (at least) HR, RR, temperature, BP, Capillary refill
    • Option 1: NGT fluid (maintenance + deficit)
    • Option 2:  IV fluids 0.9% saline + 5% dextrose (maintenance + deficit)
Severe Dehydration
    • Insert IV cannula, check FBC, U&E and BGL (VBG)
    • IV fluid bolus: 20 mL/kg bolus of 0.9% saline (repeated if required)
    • Admit under the General Paediatric Team
    • Investigate possible underlying causes
    • Continue IV fluids: 0.9% saline + 5 % glucose (maintenance + deficit  over 24 hours)
    • If hypernatramic (Na > 150mmol/L) IV fluids are to be given over 48-72 hours


Fluid Calculation

1. Deficit volume
Deficit volume = weight (kg) x % dehydration x 10mL

2. Maintenance
< 10kg        =   100mL / kg / 24 hours
10 – 20kg   =    1000mL + (50mL for each kg over 10kg) / 24 hours
> 20kg        =    1500mL + (20mL for each kg over 20kg) / 24 hours

3. Hourly rate
Hourly rate = (deficit volume + 24 hours maintenance fluids) divided by 24


Use the following paediatric fluid rate calculator:


  • Ondansetron can be used before a fluid trial or if the child vomits during rapid rehydration. It is not recommended as a discharge medication.
  • No other anti-emetics or anti-diarrhoeal agents are to be used in infants or children with suspected gastroenteritis.

Admission criteria

  • Failed rapid rehydration with nasogastric tube (NGT)
  • Severe dehydration requiring intravenous fluids

Referrals and follow-up

  • Mild dehydration who are sent home after oral fluid trial should have a GP review at 24 hours


  • Ensure all children are weighed (bare weight < 12 months old, light clothing for all other children)
  • Ensure the child is reweighed prior to discharge
  • Utilise the appropriate rehydration form if the child is having a trial of fluids


  • Baseline observations include HR, RR, temperature, BP and capillary refill
  • Minimum of hourly observations should be recorded whilst in the Emergency Department
  • Any significant changes should be reported immediately to the medical team
  • Fluid input/output is to be monitored and documented


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