Pediatric IV Fluids: Bolus and Maintenance
Two separate questions: is the child shocked (needs a bolus) or euvolaemic but nil-by-mouth (needs maintenance)? Don’t conflate them.
Resuscitation bolus
Use an isotonic crystalloid (0.9% sodium chloride or balanced solution such as Plasma-Lyte / Ringer’s lactate).
| Scenario | Bolus volume | Notes |
|---|---|---|
| Compensated/decompensated shock | 10–20 mL/kg | Give over 5–10 min, reassess after each |
| Trauma / suspected haemorrhage | 10 mL/kg | Move early to blood products |
| DKA | 10 mL/kg over 30–60 min | Cautious; avoid rapid large boluses |
| Neonate | 10 mL/kg | Reassess; smaller aliquots |
Reassess (HR, perfusion, mental status, urine output, liver edge for overload) after every bolus. Escalate to inotropes / senior help if poor response after 40–60 mL/kg. Avoid hypotonic fluids for resuscitation.
Maintenance (Holliday-Segar “4-2-1” rule)
For the well, nil-by-mouth child. Use an isotonic, glucose-containing maintenance fluid (e.g. 0.9% NaCl + 5% dextrose ± KCl once passing urine) — hypotonic maintenance fluids risk iatrogenic hyponatraemia (NICE NG29).
| Body weight | Hourly rate | Daily volume |
|---|---|---|
| First 0–10 kg | 4 mL/kg/h | 100 mL/kg/day |
| Next 10–20 kg | + 2 mL/kg/h (for each kg 11–20) | + 50 mL/kg/day |
| Each kg > 20 kg | + 1 mL/kg/h | + 20 mL/kg/day |
Worked example (24 kg child): (4×10) + (2×10) + (1×4) = 64 mL/h.
Daily maximum typically capped around adult maintenance (~2400 mL/day in females, ~2600 mL/day in males). Restrict to ~⅔ maintenance where SIADH is likely (meningitis, bronchiolitis, post-op).
👉 Skip the arithmetic — use the maintenance fluid calculator.
Quick checks
- Bolus = resuscitation (isotonic, rapid, reassess). Maintenance = upkeep (isotonic + glucose, steady rate).
- Always account for ongoing losses and deficit separately from maintenance.
- Recheck electrolytes within 24 h of starting IV fluids; watch sodium.
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.