Summary
- Maintenance fluid needs follow the Holliday-Segar formula: 100 mL/kg/day for the first 10 kg, 50 mL/kg/day for the next 10 kg, and 20 mL/kg/day for each kg over 20 kg [1].
- Isotonic fluids (0.9% saline or balanced crystalloid) are standard for maintenance therapy. Routine use of hypotonic fluids (0.2% saline) is associated with iatrogenic hyponatremia, seizures, and death, and is no longer recommended [2].
- Dehydration severity is graded clinically as mild (3-5%), moderate (6-9%), or severe (10% or greater), based on mucous membranes, skin turgor, capillary refill, heart rate, blood pressure, and mental status [3,4].
- Fluid deficit (mL) = Weight (kg) × Dehydration (%) × 10.
- Oral rehydration therapy is first-line for mild to moderate dehydration without shock, with success rates above 90% [5].
- The two-bag system allows independent titration of dextrose delivery in DKA without interrupting the insulin infusion or changing the fluid rate [7,8].
Caution. Hypotonic maintenance fluids are reserved for specific indications, documented hypernatremia requiring gradual correction, severe SIADH, or select cardiac conditions. They are not routine maintenance fluid [2].
Maintenance requirements: Holliday-Segar
| Weight band |
Rate |
| First 10 kg |
100 mL/kg/day |
| Next 10 kg (10-20 kg) |
50 mL/kg/day |
| Each kg above 20 kg |
20 mL/kg/day |
The formula dates to 1957 and remains the reference standard for NPO maintenance calculation [1].
Clinical pearl. A 25 kg child: (10 × 100) + (10 × 50) + (5 × 20) = 1600 mL/day, approximately 67 mL/hr.
Fever raises metabolic rate and fluid requirement. Add approximately 10-12% of calculated maintenance per degree Celsius above 38°C.
Calculate maintenance fluids →
Isotonic versus hypotonic fluids
Hospitalized children were historically given hypotonic fluids (0.2% saline) as routine maintenance therapy. This practice produced iatrogenic hyponatremia, seizures, and mortality and is no longer considered appropriate [2].
- Standard maintenance: isotonic fluids, 0.9% normal saline or a balanced crystalloid. These match plasma osmolality and do not induce hyponatremia [2].
- Hypotonic fluids, limited indications: documented hypernatremia requiring gradual correction, severe SIADH, or specific cardiac conditions.
Clinical assessment of dehydration
| Severity |
Fluid deficit |
Findings |
| Mild |
3-5% |
Dry lips, slightly decreased skin turgor, normal mental status |
| Moderate |
6-9% |
Visibly dry mucous membranes, reduced skin turgor, compensatory tachycardia |
| Severe |
≥10% |
Skin tenting, altered mental status, weak pulses, cool extremities, possible hypotension |
Assessment requires systematic evaluation of capillary refill time, mucous membrane moisture, skin turgor, heart rate, blood pressure, and mental status. Individual signs correlate imperfectly with degree of dehydration when used alone [3,4].
Assess dehydration with the Gorelick Scale →
Deficit calculation and replacement route
Deficit (mL) = Weight (kg) × Dehydration (%) × 10
Clinical pearl. A 10 kg child who is 8% dehydrated has an 800 mL deficit.
| Clinical scenario |
Preferred route |
Notes |
| Mild to moderate dehydration, no shock |
Oral rehydration therapy, low-osmolarity solution |
Success rate exceeds 90% over several hours [5] |
| Unable to tolerate oral intake, shock, or severe dehydration |
Intravenous therapy |
20 mL/kg isotonic crystalloid bolus for shock; 4-6 hour replacement for stable moderate dehydration |
Calculate fluid deficit →
DKA fluid management: the two-bag system
Children with diabetic ketoacidosis typically present with 5-10% dehydration, metabolic acidosis, and total body potassium depletion. Serum potassium may be normal or high initially due to extracellular shift from acidosis and insulin deficiency [9,10].
Two premixed bags, same base fluid, different dextrose concentration:
| Bag |
Composition |
| Bag 1 |
0.9% NS (or 0.45% NS) with potassium, no dextrose |
| Bag 2 |
Same base fluid with 10% dextrose and potassium |
Adjusting the relative infusion rates of the two bags, while keeping the total rate constant, titrates dextrose delivery to keep glucose declining at 50-100 mg/dL/hour without interrupting the insulin infusion. This avoids the repeated bag changes required by traditional single-bag protocols [7,8].
| Parameter |
Target |
| Insulin infusion |
0.05-0.1 units/kg/hour, no bolus |
| Potassium replacement |
20-40 mEq/L once serum K⁺ <5.5 mEq/L and urine output established |
| Deficit replacement |
Even over 24-48 hours |
| Glucose decline |
50-100 mg/dL/hour |
Calculate DKA two-bag fluids →
Replacement of ongoing losses
- Vomiting and nasogastric losses deplete potassium and chloride.
- Diarrhea causes bicarbonate losses.
- Replace ongoing losses milliliter-for-milliliter with matched electrolyte composition.
- Fever and tachypnea increase insensible losses. Add approximately 10-12% of calculated maintenance per degree Celsius above 38°C.
| Age group |
Target urine output |
| Young children |
1-2 mL/kg/hour |
| Older children |
0.5-1 mL/kg/hour |
Output below these targets suggests inadequate perfusion or renal dysfunction.
References
- Holliday MA, Segar WE. The maintenance need for water in parenteral fluid therapy. Pediatrics. 1957;19(5):823-832. doi:10.1542/peds.19.5.823
- Feld LG, et al. Clinical Practice Guideline: Maintenance Intravenous Fluids in Children. Pediatrics. 2018;142(6):e20183083. doi:10.1542/peds.2018-3083
- Gorelick MH, Shaw KN, Murphy KO. Validity and reliability of clinical signs in the diagnosis of dehydration in children. Pediatrics. 1997;99(5):E6. doi:10.1542/peds.99.5.e6
- Steiner MJ, DeWalt DA, Byerley JS. Is this child dehydrated? JAMA. 2004;291(22):2746-2754. doi:10.1001/jama.291.22.2746
- AAP Committee on Nutrition. Practice parameter: the management of acute gastroenteritis in young children. Pediatrics. 1996;97(3):424-435. doi:10.1542/peds.97.3.424
- Freedman SB, Adler M, Seshadri R, Powell EC. Oral ondansetron for gastroenteritis in a pediatric emergency department. N Engl J Med. 2006;354(16):1698-1705. doi:10.1056/NEJMoa055119
- Grimberg A, Cerri RW, Satin-Smith M, et al. The "Two Bag System" for variable intravenous dextrose and fluid administration: benefits in diabetic ketoacidosis management. J Pediatr. 1999;134(3):376-378. doi:10.1016/s0022-3476(99)70469-5
- Poirier MP, Greer D, Satin-Smith M. A prospective study of the "two-bag system" in diabetic ketoacidosis management. Clin Pediatr (Phila). 2004;43(9):809-813. doi:10.1177/000992280404300904
- Wolfsdorf JI, Glaser N, Agus M, et al. ISPAD Clinical Practice Consensus Guidelines 2018: Diabetic ketoacidosis and the hyperglycemic hyperosmolar state. Pediatr Diabetes. 2018;19 Suppl 27:155-177. doi:10.1111/pedi.12701
- Glaser N, Fritsch M, Engel S, et al. ISPAD Clinical Practice Consensus Guidelines 2022: Diabetic ketoacidosis and the hyperglycemic hyperosmolar state. Pediatr Diabetes. 2022;23(7):835-856. doi:10.1111/pedi.13406