Two-Year-Old With Acute Diarrhea: Dehydration Severity and an Order That Needs Questioning
Leo, age 2, weighs 12.0 kg today, down from 12.9 kg three days ago. He has had 3 days of vomiting and watery diarrhea, up to 8 stools per day. His mother has offered small amounts of oral rehydration solution, but he refuses most of it. He is lethargic but cries and pulls away during venipuncture, with no tears. Heart rate 152, respiratory rate 34, temperature 38.4 C, blood pressure 84/50, capillary refill 3 seconds. Mucous membranes are dry and skin tents over the abdomen. He has had one wet diaper in the past 11 hours and the urine was dark. Sodium 133 mEq/L, potassium 3.2 mEq/L, bicarbonate 14 mEq/L, BUN 32 mg/dL, creatinine 0.5 mg/dL. Orders: 0.9% sodium chloride 20 mL/kg IV over 20 minutes, may repeat once; then D5 0.45% sodium chloride with 20 mEq/L potassium chloride at 44 mL/hour; ondansetron 2 mg IV once.
1. Classify Leo's dehydration as mild, moderate, or severe, using the specific findings. Calculate the bolus volume and the infusion rate.
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He is moderately dehydrated, approximately 7%. Weight loss is 0.9 kg of 12.9 kg, which is about 7%; mild is roughly 3-5%, moderate 6-9%, severe 10% or more with shock. Supporting moderate findings: lethargy yet responsive to pain, absent tears, dry mucous membranes, skin tenting, capillary refill of 3 seconds, tachycardia, and marked oliguria with concentrated urine. Findings that would push toward severe - mottling, weak thready pulses, unresponsiveness, profound hypotension - are absent, and he still has a measurable blood pressure and interacts. The bicarbonate of 14 and BUN of 32 with a creatinine of 0.5 fit dehydration with a prerenal pattern rather than established renal failure.
Bolus: 20 mL/kg x 12 kg = 240 mL over 20 minutes. Rate: 240 mL in 20 minutes = 720 mL/hour, delivered by infusion pump or a measured manual push with a calibrated chamber, not an unregulated gravity line. Reassess during and immediately after the bolus; a child can worsen quickly and fluid overload is equally dangerous.
2. Which of the ordered therapies should the nurse clarify before administering, and why? How would you raise the concern?
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The potassium in the maintenance fluid is the item to question. Potassium chloride should generally not be added until urine output is established, because an oliguric child given potassium can become hyperkalemic, and this child has produced one wet diaper in 11 hours with a prerenal laboratory pattern. He is currently hypokalemic at 3.2, so replacement will be needed - the issue is the timing and route, not the goal. The safe course is to start the maintenance fluid without potassium, confirm voiding after the bolus, then add it per protocol at a concentration no higher than usual for peripheral administration.
Raise it as a safety question, not a refusal: call the prescriber, state the finding (one wet diaper in 11 hours, BUN 32, potassium 3.2), state the concern (adding potassium before urine output returns), and propose a plan (start without potassium, reassess output, add when voiding). Document the conversation. The 2 mg ondansetron dose is appropriate for 12 kg (about 0.15 mg/kg) and the 44 mL/hour maintenance rate matches the 4-2-1 calculation for 12 kg, so neither requires clarification.
3. After the first 20-minute bolus, what specific reassessments tell you whether a second bolus is needed?
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Reassess before deciding - do not simply run the second bolus because it was ordered as a may repeat. Look for perfusion and hydration endpoints, not just one number:
- Heart rate trending down toward his age-appropriate range and capillary refill at or under 2 seconds
- Improved mental status and responsiveness, and tears returning
- Blood pressure stable or improved, with strong peripheral pulses and no mottling
- Moistening of mucous membranes and resolution of skin tenting
- Urine output: a wet diaper, lighter urine color, and a measurable output
- Repeat weight, and tolerance of oral fluids if a trial is appropriate
A second bolus is justified if tachycardia, delayed capillary refill, lethargy, or oliguria persist after the first. Also reassess for overload during any bolus - increasing respiratory rate, new crackles, hepatomegaly, or a falling SpO2 - and stop if those appear. Document the pre- and post-bolus findings so the decision is auditable.