Fluids

Question 1

Principles of paediatric fluid therapy:

Answer 1

• Always give PO or NG if able (Hydralyte, Gastrolyte)
• Preferred IV fluid is 0.9% saline + 5% dextrose
  –> Can be Hartmanns or Plasmalyte instead, but always with the 5% dex
• Well and fasting get FULL maintenance
• Sick get TWO THIRDS maintenance
  –> ADH excess. Avoid overload + hypoNa
• Neonates get 10% dextrose day 1, then ‘stamp’ (Half normal saline + 10mmol KCL + 5% dextrose)
• 100mls/hr is max for any child (unless special cicumstance)

Question 2

How to calculate MAINTENANCE fluid in paeds:

Answer 2

0.9% saline + 5% dextrose preferred

• 4mls/kg/hr for 10kg
• 2mls/kg/hr next 10kg
• 1ml/kg/hr per remaining kg
  …… this is for first 24 hours.

….. give TWO THIRDS if sick (UNLESS dehydrated)
______________

If sugar needed: change to 10% dextrose

If K needed: add 20mmol KCL per L

Question 3

How to calculate DEFICIT REPLACEMENT fluid in paeds:

Answer 3

Deficit = % dehydration x Kg x 10 mls
—> (50/kg dehy, 100/kg shock)

Replace over:
- 4 hrs gastro
- 24 hrs viral
- 48 hrs DKA

In ADDITION to maintenance

____________________
Unless recorded weight difference, then % dehydration is a clinical estimate:

Dehydrated = 5%
Shocked = 10%

(May also wish to measure + replace losses each 4 hours)

Question 4

A 15kg 4yo boy has gastro. He is vomiting all PO fluids, is clinically shocked and is 10% dehydrated. Calculate his fluid requirements for the next 24/24:

Answer 4

Even though sick, gets FULL maintenance because dehydrated

Question 5

Discussion points: Hartmanns vs Saline vs 0.5% dextrose

Answer 5

N. Saline: (Na, Cl, water)
- Isotonic
- Delivers Na as sodium chloride
- Na and Cl excessive
–> Hyperchloraemic acidosis

Hartmann’s (Na, Cl, K, Ca, Lactate for HCO3)
- Isotonic
- Electrolytes are in physiological conc.
- Delivers Na as sodium lactate
–> Lactate (NOT lactic acid)
–> WON’T contribute to acidosis. Actually delivers HCO3 when metablised.
–> WILL interfere with lactate monitoring

5% dextrose (Glucose, water)
- Hypotonic
- Rapidly redistributes: no role in resus bolus
- Energy from glucose is negligible: no role in hypoglyc
- Use for hydration, to avoid Na or Cl load.

Question 6

Composition of Fluids:

Answer 6

Question 7

What is considered ‘inadequate intake’ (ie. will need fluids)

Answer 7

<50% intake for 12 hours

Question 8

What is the regimen for paediatric Rapid Rehydration:

Answer 8

eg. Gastro

Give ORS

PO:
- 0.5ml/kg every 5 mins
- NGT: 10-25ml/kg/hr, over 4 hours

NGT pumps max out at 30ml/hr rate