When correcting fluid losses in children, we need to replace:
The ongoing losses can be easily calculated from measuring what is being lost.
The Maintenance fluids are similarly very simple to calculate:
kg 24 hour
<10 100 mL/kg
10–20 1000+ 50mL/kg above 10kg
>20 1500 + 20mL/kg above 20kg
Clinical Derivation of degree of dehydration is inaccurate. The best method is to look at the weight loss of the child, although this may not be available prior to presentation. The method we therefore use is a combination.
Firstly determine the degree of dehydration clinically:
Mild Dehydration is usually not discernible
Moderate Dehydration is described as 4-6%. There is usually delayed capillary refill (>2 sec) and increased reap rate.
Severe Dehydration is > 7%. Cap refill is > 3 sec, skin is mottled and patient is tachycardic
Calculating Water Deficit
If the patient weighs 10kg and is moderately dehydrated ie., 5% dehydrated, then the deficit is:
5/100 x 10 =0.5 in Litres ie 500ml
What Fluids to Use?
Initial resuscitation boluses of 20ml/kg of normal saline can be used.
For maintenance IV fluid 5% dextrose and 0.9% Normal Saline can be used, remembering to correct potassium.
For oral rehydration Gastrolyte and similar products may be used.
How quickly to rehydrate.
In a resuscitation situation, obviously fluids will be given quickly. In other situations they can be replaced at slower rates. Some literature recommends replacing 50% of the deficit within the first 8 hours and then the remaining 50% over the next 16 hours.
In conditions such as gastroenteritis fluid may be replaced rapidly i.e.., over hours. In nasogatric fluid resuscitation 25ml/kg per hour can be replaced foe the firs 4 hours, i.e.., in a 10kg child one litre can be given over 4 hours.
BEWARE Rapid fluid resuscitation in DKA as cerebral oedema may occur. Please read the blog on DKA and Cerebral Oedema.
Watch the Video on FLUID RESUSCITATION IN CHILDREN