What is the appropriate choice of maintenance intravenous (IV) fluids for a 7-month-old infant?

From the Guidelines

For a 7-month-old infant requiring maintenance fluids, I recommend using an isotonic solution, such as 0.9% saline or a balanced solution with a similar tonicity, with 20 mEq/L of potassium chloride, as it provides the best balance between preventing hypoglycemia and avoiding excess free water that could lead to hyponatremia 1. The fluid rate should be calculated using the Holliday-Segar method: 100 mL/kg/day for the first 10 kg of body weight.

• For example, a 7 kg infant would need approximately 700 mL/day or 29 mL/hour.
• This isotonic solution helps maintain serum sodium levels, and the added potassium prevents hypokalemia during maintenance therapy. Some key points to consider when choosing maintenance fluids for a 7-month-old infant include:
• The use of isotonic fluids to reduce the risk of hyponatremia 1
• The consideration of balanced solutions to slightly reduce length of stay 1
• The importance of regularly monitoring electrolytes, especially in the first 24 hours of fluid therapy 1
• The need to adjust fluid composition based on the infant's clinical status, abnormal electrolytes, dehydration, or specific medical conditions like cardiac or renal disease 1 It's also important to note that the total daily amount of maintenance fluid therapy should be considered, including IV fluids, blood products, all IV medications, arterial and venous line flush solutions, and enteral intake, to prevent fluid creep and reduce fluid intake 1. Always reassess the infant's clinical status frequently and adjust fluids based on ongoing losses, oral intake, and laboratory values.

From the Research

Maintenance Fluids for 7-Month-Old Infants

• The choice of maintenance fluids for a 7-month-old infant is crucial for their growth and development.
• According to a narrative review published in 2023 2, most nutrition guidelines recommend avoiding foods with added salt for infants aged 6-12 months, but the evidence for this recommendation is limited.
• The review found that the kidneys of infants aged 6-12 months have adequate sodium excretion capacity, and there is insufficient evidence to suggest that high salt intake early in life leads to hypertension or salty diet preference in adults.
• However, infants aged 6-12 months may be at risk of low sodium intake if their supplementary food is not adequately salted.

Factors Affecting Fluid Consumption

• A systematic review published in 2023 3 found that the early introduction of fluids and water affects the duration of breastfeeding, the infant immune system, and possibly causes infants to consume less breast milk.
• The review found that 86.2% of infants were around 6 weeks old when they first consumed water, and the prominent reasons for making infants drink water were the thought that they need it and cultural reasons.
• Exclusive breastfeeding of 0-6-month-old infants is recommended by reliable health authorities, and nurses play a key role in implementing this practice.

Considerations for Maintenance Fluids

• A study published in 2005 4 found that high salt intake can lead to increased blood pressure and proteinuria in patients with chronic kidney disease.
• Another study published in 2015 5 found that the use of loop diuretics is associated with increased mortality in patients with suspected coronary artery disease, but without systolic heart failure or renal impairment.
• A well-child visit guideline published in 2018 6 recommends comprehensive assessment of a child, including a review of growth, immunizations, and screening for postpartum depression in mothers of infants up to six months of age.