Formulae

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  • NOTE: Always follow local and up-to-date clinical guidelines / protocols.
  • This page is a guide only.


Contents

Normal Clinical Parameters

Resuscitation

(after APLS)

  • A- age
  • W - weight: (age+4)x2
  • E - energy. 4joules/kg
  • T - tube. int diameter: (age/4)+4. Neonate 3.5mm
  • F - fluid. 20 ml/kg (10mg/kg in trauma and DKA)
  • A - adrenaline. 0.1 ml/kg 1:10 000 (10 mcg/kg)
  • G - glucose iv bolus. 5ml of 10% per kg. Or 10ml of 5%


  • Systolic Blood pressure ~ 80 + (2 X Age in years) /mmHg


Caution - Weight as estimated by 2(age + 4) is seriously inaccurate especially for older children. See Luscombe and Owens (ADC 2007;92;412-415). The underestimate on APLS formula is up to 20%. (3Xage)+7 proves much more accurate.

Fluid Calculations

General Paediatrics

  • Fluid requirements.
    • daily: 100 : 50 : 20 : 10 : 10 : 10 etc... ml per 10kgs per 24hrs
    • hourly: 4+2+1 ml/hr
  • dehydration correction: % dehy x 10 x weight in kg /ml


Neonatal Fluids

Fluids (milk or IV fluids) are usually calculated "per kg per day" ( ml/kg/day), with amounts increased from days 1 to 4 (follow your local hospital protocol).

Eg:

  • Day 1: 60 ml/kg/day
  • Day 2: 90 ml/kg/day
  • Day 3: 120 ml/kg/day
  • Day 4 and thereafter: 150 ml/kg/day


Fluid regimes may be altered depending on the condition of the baby, for example where there are concerns regarding hypoxic-ischaemic encephalopathy / cerebral oedema, cardiac lesions or a clinically significant persistent ductus arteriosus (PDA).

Once established on full fluids, amounts may be increased to promote growth / weight gain and good nutrition.


Blood Product Administration


Product Prescription
Packed Red Cells 4 x (rise in Hb required) x weight = Packed RBC (ml)

Simple top-up: aim for Hb 10-12 g/dL
GI bleed / varices / post-transplant: aim for Hb 8-10 g/dL
Platelets 10 ml/kg over 30 minutes
Fresh Frozen Plasma 10 ml/kg over 1 hour
Cryoprecipitate 5 ml/kg over 30 - 60 minutes

Electrolyte Corrections


Electrolyte Treat if less than: IV Correction Daily Maintenance
Bicarbonate pH 7.0 0.3 x base deficit x weight
(over 30-60 mins)
(Dilute 1 in 5 in 0.9% saline or 5% dextrose via central line)
Calcium 2 mmol/L 0.5 ml/kg 10% Calcium Gluconate
(max 20ml over 10 minutes)
(Dilute 1 in 5 in 0.9% saline or 5% dextrose)
1 mmol/kg
Glucose 3 mmol/L 3 - 5 ml/kg 10% dextrose 4-6 mg/kg/min
Magnesium 0.75 mmol/L 0.5 mg/kg Magnesium Sulphate
(max 10ml, over 10 minutes)
0.2 mmol/kg
Phosphate 0.8 mmol/L 0.05 mg/kg/hour Sodium or Potassium Phosphate
for 3-7 hours
Dilute 1 in 10 0.9% saline or 5% dextrose
0.4 - 1.5 mmol/kg
Potassium 3 mmol/L 0.25 - 0.5 mmol/kg Potassium Chloride
over 1-2 hours with cardiac monitoring
Dilutre to 4 mmol KCl per 10ml 0.9% saline via central line
1 - 2.5 mmol/kg
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