From the Guidelines
The recommended fluid dosing for infants is 100 mL/kg/day for the first 10 kg of body weight, with adjustments for additional weight and severity of illness, as maintenance fluids typically consist of solutions with 40-60 mEq/L of sodium for prevention of dehydration or maintenance of hydration status. When considering the fluid dosing for infants, it's crucial to take into account their unique physiological characteristics, such as a higher metabolic rate and an immature renal system that cannot concentrate urine effectively 1. For infants, particularly those who are sick or dehydrated, the fluid requirements may increase by 10-50% depending on the severity of the illness. Key considerations include:
- The use of oral solutions with 40-60 mEq/L of sodium for maintenance or prevention of dehydration, as recommended by the American Academy of Pediatrics (AAP) 1.
- Monitoring fluid status closely through weight checks, urine output (with a goal of 1-2 mL/kg/hour), vital signs, and clinical assessment to avoid both dehydration and fluid overload.
- Adjusting the fluid dosing based on the infant's weight, with a graduated approach that accounts for their higher body surface area to weight ratio and metabolic demands. Given the importance of sodium content in oral rehydration solutions, as highlighted by the Centers for Disease Control and Prevention 1, it's essential to choose solutions that closely approximate the stool-sodium losses encountered in patients with viral diarrhea, which is common in infants.
From the Research
Fluid Dosing for Infants
The recommended fluid dosing for infants can vary depending on their age, weight, and medical condition.
- For low-birth-weight infants, a study published in 1992 2 found that fluid restriction during the first weeks of life can improve outcomes and reduce the risk of bronchopulmonary dysplasia. The study suggested a fluid intake of 50-120 ml/kg/day during the first week and 150 ml/kg/day until four weeks of age.
- Another study published in 1983 3 estimated the optimal fluid requirement for very low birthweight infants to be around 150 ml/kg/day, based on the incidence of hypernatremia and weight loss in these infants.
- For infants with septic shock, a randomized controlled trial published in 2017 4 compared the effect of administering fluid boluses over 15-20 minutes versus 5-10 minutes. The study found that administering fluid boluses over 15-20 minutes resulted in fewer children needing mechanical ventilation or having an increase in oxygenation index.
- A study published in 2010 5 found that early initiation of total parenteral nutrition (TPN) and restricted fluid intake in very preterm infants did not influence serum sodium and potassium levels in the first three postnatal days, but did result in decreased diuresis and loss of body weight.
Key Findings
- Fluid restriction during the first weeks of life may improve outcomes for low-birth-weight infants 2.
- The optimal fluid requirement for very low birthweight infants may be around 150 ml/kg/day 3.
- Administering fluid boluses over 15-20 minutes may be beneficial for infants with septic shock 4.
- Early initiation of TPN and restricted fluid intake may not influence serum electrolyte levels, but can affect diuresis and weight loss in very preterm infants 5.