Fluid bolus therapy and vasoactive support — formative SAQs

1. Fluid bolus prescription

I give 10 to 20 mL per kilogram of isotonic crystalloid — 0.9 per cent sodium chloride or a balanced crystalloid such as Hartmann solution. For this 16 kilogram child, that is 160 to 320 mL per aliquot, given over 5 to 20 minutes using a push-pull technique or rapid infuser, not as a slow gravity drip. I use a large-bore peripheral intravenous cannula or intraosseous access if peripheral is not achievable. ^{[2] [3]}

2. Reassessment after each bolus

After each aliquot I perform the full reassessment: heart rate and pulse quality, skin colour and temperature, capillary refill with the technique stated, blood pressure, mental state, respiratory rate and work of breathing, auscultation for new crackles, and liver span for hepatomegaly. I expect the heart rate to fall toward the normal range, pulses to strengthen, capillary refill to shorten, skin to become warmer and drier, and interaction to improve. I check a point-of-care lactate and glucose at baseline and repeat after each significant intervention. ^[4]

3. No improvement after two boluses

This is fluid-refractory shock: two aliquots totalling 40 mL per kilogram have produced no sustained improvement. I stop giving further fluid blindly. I reassess for signs of overload — if crackles, hepatomegaly, gallop or worsening respiratory distress are present, I stop fluids immediately. I start a vasoactive infusion now, choosing the agent based on the shock phenotype. I call PICU or retrieval in parallel. I do not wait for a third bolus to fail before escalating. ^{[2] [3]}

4. Warm shock phenotype and first-line vasoactive

Bounding pulses, warm dry skin and flash capillary refill define warm vasodilatory shock. The first-line vasoactive agent is noradrenaline, starting at 0.05 to 0.5 micrograms per kilogram per minute, titrated to clinical response. I prefer central venous access but use intraosseous access if central is not immediately available, and I do not delay the first dose to place a central line. ^{[3] [4]}

5. The first-hour ceiling

The Surviving Sepsis Campaign 2026 children guideline supports up to 40 to 60 mL per kilogram of crystalloid in the first hour for septic shock. I treat this as a ceiling — a maximum — rather than a target, because driving toward a fixed volume without measuring the response risks pushing the child onto the flat portion of the Frank-Starling curve, causing fluid accumulation, pulmonary oedema and worse outcomes. The Alobaidi meta-analysis confirms the association between positive fluid balance and harm. I stop for no benefit, worsening, or overload at any point below the ceiling. ^{[2] [10]}