A 12 kg child in shock from diarrhoea: Plan C fluids, drip rates and the limits of gravity
A 3-year-old boy weighing 12 kg is brought to a railway hospital casualty at 22:00 with a 3-day history of watery diarrhoea and vomiting, and refusal of feeds since morning. He is lethargic, has sunken eyes, no tears, a skin pinch that retracts in 3 seconds, dry mucous membranes, capillary refill of 4 seconds, a weak pulse of 142/min, respiratory rate 42/min with deep breathing, temperature 37.6 °C, and has passed no urine for 8 hours. There is no blood in the stool and no obvious severe acute malnutrition. The ward has Ringer's lactate, 0.9% sodium chloride, oral rehydration salts sachets, zinc dispersible tablets 20 mg, one volumetric infusion pump, giving sets of 15 drops/mL and 60 microdrops/mL, and 100 mL burettes. The doctor has been called to a level-crossing accident and the nurse must begin treatment under standing orders.
1. Classify the dehydration and set out the full fluid plan with volumes and timings for this child.
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Classification: severe dehydration with shock (WHO/IMNCI Plan C). The grounds are lethargy, sunken eyes, a skin pinch of 3 seconds, very delayed capillary refill and a weak fast pulse - two or more severe signs plus poor perfusion. He needs intravenous fluid, not oral rehydration alone.
Fluid plan (total 100 mL/kg = 1,200 mL of Ringer's lactate), child older than 12 months:
- First 30 minutes: 30 mL/kg = 360 mL over 30 minutes.
- Next 2 hours 30 minutes: 70 mL/kg = 840 mL.
- Total 1,200 mL in 3 hours.
Reassessment: at 30 minutes and then hourly. If perfusion, pulse volume and conscious level are improving, continue the plan; if there is no improvement, repeat the 30 mL/kg bolus and reassess for other causes (sepsis, cardiac, hypoglycaemia).
Alongside the drip: check and treat hypoglycaemia, keep him warm, weigh him, continue breastfeeding if he can suck, and once he can drink start oral rehydration solution at about 5 mL/kg/hour (60 mL/hour). Give zinc 20 mg once daily for 14 days (he is over 6 months). Antibiotics are not routine for watery diarrhoea without blood or suspected cholera. Reassess and record at every step, because the doctor is absent and your record is the only handover.
2. You must deliver 30 mL/kg in 30 minutes. Calculate the drip rate for each giving set available and justify which method you would choose.
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Rate: 360 mL in 30 minutes = 12 mL/minute = 720 mL/hour.
With the 15 drops/mL set: 360 × 15 ÷ 30 = 180 drops/min - three drops every second. This can be counted only by continuous hand regulation; the roller clamp drifts, a change of posture alters the flow, and no one would hear if it ran too fast or stopped.
With the 60 microdrops/mL set: 360 × 60 ÷ 30 = 720 microdrops/min - twelve drops a second, which cannot be counted reliably at all.
Decision: use the volumetric infusion pump, primed correctly with the correct set, with occlusion and air-in-line alarms set, and check the volume infused against the prescribed volume every 15 minutes. If the single pump is already committed to a sicker child, use a 100 mL burette with a microdrop set so the volume is capped, count the drops for one minute every 5–10 minutes, and stay with the child - do not leave a rapid gravity infusion running unobserved. In a 12 kg child, fluid overload can cause pulmonary and cerebral oedema within minutes; the burette limits the volume that can be given if the clamp is knocked or mis-set. Document the method chosen, the rate, and the volumes infused hourly.
3. Three hours later he is passing urine and is more alert, but his eyes are still sunken. What is your next step, what would make you suspect overhydration, and what must not be stopped?
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Next step: sunken eyes are a tissue sign that lags behind circulatory recovery and can persist for days after perfusion is restored. Passing urine and improved consciousness mean the resuscitation has worked. Do not give further boluses for tissue signs alone. Switch to Plan B: oral rehydration solution 75 mL/kg over 4 hours (about 900 mL), plus replacement of ongoing losses at roughly 10 mL/kg per loose stool, continuing breastfeeding on demand. Reassess at 4 hours and then decide between continuing oral therapy and further intravenous fluid.
Signs of overhydration to act on: rising respiratory rate, basal crackles, a new third heart sound, puffy eyelids, sudden weight gain, restlessness or a bulging fontanelle in an infant. Stop the infusion, sit the child up, give oxygen and call the doctor immediately - do not wait for the next round.
Must not be stopped: zinc 20 mg daily for 14 days, even after rehydration, because it shortens the diarrhoea and reduces recurrence in the following months. Also continue counselling on hand-washing, safe drinking water, food hygiene and the danger signs that bring the child back: blood in the stool, no urine, repeated vomiting, drowsiness or inability to drink.