Paediatric Fluid Replacement

Fluid bolus

10-20mg/kg

PALS = 10mg/kg

Repeat as needed

What % dehydrated = hypovolemic shock

10%

How to estimate weight

0-10 = (age+4) x 2

>10yo = age x 3.3

Why 2/3 maintenance in an unwell child? Who gets full (3), who gets 50% (4)

Sick child with inflammation = SIADH

Water retained (independently of sodium) = dilutional hyponatremia

Sodium stays extracellular, low osmolarity means water moves freely across cell membranes into cell through osmosis, cells swell (including brain) seizures, confusion, coma

Inflammatory illness = increased membrane permeability = fluid and Na+ into the interstitial space (circulatory depletion while fluid overloaded at a tissue level)

FULL MAINTENANCE for DKA, some Vs/Ds, NBM for surgery

LESS ~50% head injury, meningitis, electrolyte imbal, kidney disease/dialysis

ToF

10mL/kg/hr

Ondansetron

NGT rapid rehydration (who not for)

Not for <6mnths

10-25mL/kg/hr for 4hrs (mild 5% dehydrated = 10mL, moderate 10% = 25mL)

Maximum rate on pumps is 300mL therefore divide target volume by 300mL and give over that time

Eg. 20kg child, aiming 500mL x 4hrs = 2000

2000 divided by 300mLs over 6hrs 40mins

NGT slow rehydration

0-6hrs DEFICIT (max 5%) over 4hrs

-          Work out deficit by either (wt x % dehydrated MAX 5 x 10) OR (premorbid-current x 1000)

-          Eg. 24kg kid, now 23kg

24kg – 23kg = 1 x 1000 = 1000mL deficit (over 4 hrs = 250mL/hr)

23 x 5% dehydrated x 1000 = 1150mL deficit (over 4 hrs = 287.5mL/hr)

7-24hrs MAINTENANCE milk fed should resume normal feeds or ORS if NGT = 4,2,1 rule x 24hrs / rest of 18hrs (2/3 if unwell)

4,2,1 rule

4 x first 10kg

2 x second 10kg

1 x remaining kg

IV rehydration

maintenance (4,2,1 rule) x 24 + deficit + ongoing losses over 24hrs

OR 2/3 maintenance for inflammatory illnesses.

Calculation of % dehydrated

Pre-morbid weight - current weight = estimated loss

eg 24 - 23.5 = 500mL deficit

24(000) divided by 100 = 240.

500 divided by 240 = ~2% deficit (falls into the “mild” column = 5%)

OR weight x % dehydrated x 10

eg 24 × 2 × 10 = ~480mL (deficit)