Fluids In ICU

• Fluids should be thought of as any other drug/medication in ICU; an under-resuscitated child as well as an overloaded child both have deleterious effects.
• Therefore, fluid therapy prescriptions must be tailored and appropriate for each child’s clinical condition.
• Fluids need to be considered under:
  • Resuscitation – need for bolus therapy: 10–20 mL/kg, rapid administration, isotonic crystalloids.
  • Rehydration – slower administration with regular re-evaluation, decreasing infusion as the child improves.
  • Maintenance – restricted due to general lower requirements when in ICU.
  • Ongoing losses – the need to add additional specific fluids, e.g.: burns, DKA, cerebral salt wasting, dehydrating diarrhoeas, bowel fistulae etc.
• As soon as a child is able to feed enterally, a de-escalation approach to stopping all IV fluids as soon as possible and aiming for all fluids and feeds to be given enterally (orally or via gastric tubes).
• Critically ill children have important considerations specific to fluid prescriptions:
  • Sedated and ventilated.
  • Humidified ventilator circuits.
  • Increased ADH production (SIADH).
  • Overhead warmers for small infants.
  • Decreased energy expenditure.
  • Oliguria and anuria.
• These result in fewer insensible losses compared to normal children.
• In particular groups, i.e. head injuries, those with increased ADH (pneumonia, intracranial infection), and post-operative patients, this may be 60–80% of the maintenance volume outlined by the formulae below.
• Fluids should, therefore, be adjusted accordingly, on a patient-by-patient basis.
• There must be a very good reason why you are giving crystalloid instead of nutritive enteral feeds to any paediatric ICU patient.
• Maintenance fluids must be isotonic crystalloids, (balanced solutions or 0.9% saline) with added dextrose.

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Note:
The ideal maintenance fluid is enteral feed.

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Maintenance fluid requirements in ill children:

Age	Fluid requirements
1–3 months	100–120 mL/kg/day
3–12 months	80–100 mL/kg/day
1–5 years	70–80 mL/kg/day
5–12 years	40–70 mL/kg/day

Alternatively, for critically ill children: fluid dosage needs to be 80% of the below 4/2/1 rule.

1st 10 kg	100 mL/kg/24 hours	4 mL/kg/hour
2nd 10 kg	50 mL/kg/24 hours	2 mL/kg/hour
Each next 1 kg	20 mL/kg/24 hours	1 mL/kg/hour

Composition of commonly used crystalloid (mmol/L):

	Ringers Lactate	NaCl (0.9%)	RHS (0.45%NaCl/5% dextrose)	0.45% NaCl
Na	130	154	77	77
Cl	109	154	77	77
K	4	0	0	0
Mg	0	0	0	0
Bicarb.	0	0	0	0
Lactate	28	0	0	0
Glucose	0	0	5 g	0
Ca	0	0	0	0
Osmol.	272	308	406	154
Tonicity (approx. 275–295)	272 Isotonic	308 Isotonic	154 Hypotonic	154 Hypotonic

 

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Standard Treatment Guidelines And Essential Medicines List For South Africa, Hospital Level, Paediatrics, 2023 Edition

Chapter 23: Paediatric Intensive Care,  23.5 Fluids In ICU