The 4-2-1 hourly rule: 4 mL/kg for the first 10 kg, plus 2 mL/kg for the next 10 kg, plus 1 mL/kg for each kg over 20.
Before you read
Test yourself first: 5 questions
Question 1 of 5
A client with cirrhosis develops abdominal pain, fever, and worsening ascites. Spontaneous bacterial peritonitis is suspected. Which diagnostic test should the nurse anticipate?
Answer: A. Spontaneous bacterial peritonitis is diagnosed by sampling the ascitic fluid, so the nurse anticipates a diagnostic paracentesis with cell count and culture of the fluid; a high neutrophil count in the ascitic fluid confirms infection. A barium swallow, colonoscopy, and skin biopsy do not evaluate ascitic fluid infection.
Question 2 of 5
A client is admitted with extensive burns. During the emergent (resuscitative) phase in the first 24 to 48 hours, which fluid and electrolyte change does the nurse expect?
Answer: A. In the emergent phase, increased capillary permeability causes fluid, sodium, and protein to shift from the intravascular space into the interstitium, producing hypovolemia and edema. Potassium leaks from damaged cells, causing hyperkalemia, while sodium is trapped in edema fluid, producing hyponatremia. Hemoconcentration raises the hematocrit. The opposite shifts occur later in the diuretic phase.
Question 3 of 5
A client with burns covering 40% of the body surface area is 18 hours post injury. Which electrolyte shift does the nurse expect during this emergent phase?
Answer: B. In the first 24-48 hours after a major burn (emergent/fluid shift phase), fluid and potassium move out of damaged cells into the extracellular space, and massive capillary leak occurs. The result is hyperkalemia (from cell destruction) along with hyponatremia as sodium is trapped in edema fluid. Hypokalemia develops later in the diuretic (recovery) phase.
Question 4 of 5
A client with heart failure has gained 2.2 lb (1 kg) since yesterday. The nurse interprets this weight gain as approximately how much fluid retention?
Answer: B. Each kilogram (2.2 lb) of body weight gained equals about 1 liter (1,000 mL) of retained fluid. Daily weights are the most reliable indicator of fluid status.
Question 5 of 5
A client passes a renal calculus and reports severe flank pain radiating to the groin. Nursing care includes:
Answer: B. Provide pain relief, encourage fluids (unless contraindicated) to help pass the stone, strain all urine to capture the stone for analysis, and monitor output. Restricting fluids and discarding urine are incorrect.
Keep the streak going with more questions like these, each with a full rationale.
What is pediatric fluid maintenance?
Maintenance fluids replace normal daily losses (urine, stool, insensible losses). Key principle: the 4-2-1 (or 100-50-20) rule calculates hourly and daily needs, and infants decompensate quickly with even small deficits.
Key points to remember
- The 4-2-1 hourly rule: 4 mL/kg for the first 10 kg, plus 2 mL/kg for the next 10 kg, plus 1 mL/kg for each kg over 20.
- The Holliday-Segar daily method: 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10 kg, 20 mL/kg per kg above 20.
- Infants and young children have a higher body water percentage and surface-area ratio, so they dehydrate rapidly.
- Adequate urine output is at least 1-2 mL/kg/hr in infants and small children and confirms hydration.
- Early dehydration signs include dry mucous membranes, decreased tears, sunken fontanel, and tachycardia.
- Maintenance solutions commonly use dextrose with isotonic or near-isotonic saline plus potassium once voiding is confirmed.
Nursing priorities
- Calculate maintenance fluids accurately by current weight and verify the rate with a second nurse for high-alert situations.
- Use a programmable infusion pump and document the rate; never free-flow IV fluids in a child.
- Monitor strict intake and output, daily weights, and urine specific gravity.
- Assess hydration status frequently: fontanel, mucous membranes, capillary refill, skin turgor, and vital signs.
- Add potassium to fluids only after the child has voided and renal function is confirmed.
Labs & values
Patient teaching
- For mild illness at home, offer small frequent sips of an oral rehydration solution rather than plain water or juice.
- Watch for and report fewer wet diapers, no tears, dry mouth, or unusual sleepiness.
- Continue breastfeeding or formula during diarrheal illness unless told otherwise.
Red flags: report now
- Urine output under 1 mL/kg/hr, sunken fontanel, or no tears signal worsening dehydration and need prompt action.
- Fluid overload (crackles, periorbital edema, bounding pulse, sudden weight gain) requires slowing fluids and notifying the provider.
- Never add potassium to IV fluids before the child voids; hyperkalemia risk.
References
Clinical references for this topic
