Ensuring safe and effective fluid management in infants undergoing surgery is a critical concern in pediatric anesthesia. Balancing the risks of hypoglycemia, hyponatremia, and metabolic instability has long presented a challenge. A landmark prospective study published in the British Journal of Anaesthesia offers robust evidence that a balanced electrolyte solution containing 1% glucose is both effective and safe for intraoperative maintenance in infants.

Why this matters

Infants, due to their unique physiology, are particularly susceptible to intraoperative metabolic derangements:

• High basal metabolic rate
• Limited glycogen reserves
• Immature endocrine response
• Increased sensitivity to fluid shifts

Historically, concerns about hypoglycemia led to the liberal use of glucose-rich, often hypotonic, intravenous (IV) solutions. However, these practices introduced other risks, particularly hyponatremia and hyperglycemia, prompting a reevaluation of intraoperative fluid protocols.

The study at a glance

Conducted at two major Swedish centers – Karolinska University Hospital in Stockholm and Uppsala University Hospital – this large prospective observational study included 365 infants aged 1–12 months. All underwent surgery under general anesthesia with standardized administration of a 1% glucose-balanced electrolyte solution (Benelyte, Fresenius Kabi).

• Primary goal: Determine the incidence of intraoperative hypoglycemia.
• Secondary goals: Evaluate glucose, electrolyte, ketone, and acid-base balance.

Key characteristics:

• Age range: 1–12 months (mean 5.2 months)
• Exclusions: Prematurity <44 weeks PCA, metabolic disease, hepatic impairment
• Infusion rates: 3.97 mL/kg/h median (range: 4–8 mL/kg/h)
• Monitoring: Glucose every 30–60 minutes, full blood analysis pre- and post-anesthesia

Main findings

1. No cases of hypoglycemia

• Mean plasma glucose rose from 5.3 to 6.1 mM (p<0.001)
• No infant recorded glucose <3.0 mM
• Even among the youngest infants (≤3 months), levels remained stable or improved
• Mild hyperglycemia (>8.3 mM) was rare (4.3% of patients)

This result supports that 1% glucose is sufficient to maintain normoglycemia even with modest infusion rates and prolonged fasting.

2. Sodium and chloride stayed within safe limits

• Mean sodium dropped slightly: 138 to 137.3 mM (p<0.001)
• Hyponatremia (<135 mM) rose slightly from 3.6% to 6.6%—but remained clinically insignificant
• Chloride increased from 107 to 108 mM, with 13.2% showing mild hyperchloremia at the surgery end

Infants receiving albumin boluses showed smaller sodium reductions, possibly due to their hypertonic properties.

3. Acid-base and ketone trends remained mild

• Base excess (BE) declined from −1.5 to −2.4 mM, within a safe range
• Ketone levels increased modestly, particularly in surgeries >180 minutes
• No cases of dangerous acidosis or ketosis were recorded

Ketosis, a marker of fasting stress, remained largely within acceptable thresholds.

4. Fasting did not significantly impact stability

Although 21% of infants fasted >6 hours, no association was found with adverse glucose or ketone trends.

• Median breastmilk/formula fast: 5 hours
• Only 12.3% received glucose-containing clear fluids pre-op

This suggests that adherence to updated fasting guidelines (6-4-1 rule) is generally safe when paired with appropriate fluid management.

Clinical implications

This study offers the strongest evidence to date supporting the intraoperative use of 1% glucose-balanced electrolyte fluids in infants. Its findings could lead to practice changes, including:

• Standardizing low-glucose, isotonic solutions in pediatric ORs
• Reducing unnecessary glucose supplementation
• Preventing avoidable complications such as cerebral edema from hyponatremia or hyperglycemia-induced immune impairment

Benefits of 1% glucose-balanced fluids

• Maintains metabolic and electrolyte stability
• Reduces risk of glucose and sodium disturbances
• Matches modern anesthetic practices (regional blocks, reduced fasting)

Step-by-step clinical protocol

1. Pre-op screening

• Rule out metabolic or endocrine disease
• Confirm normal liver/kidney function

2. Fasting prep

• Breastmilk: 4–6 hours
• Clear fluids: up to 1 hour pre-op

3. Start infusion

• 4–8 mL/kg/h using 1% glucose-balanced solution
• Initial rate may be higher (10 mL/kg/h) to compensate for fasting

4. Intraoperative monitoring

• Glucose: baseline, every 30–60 minutes
• Electrolytes and acid-base: at least at induction and end
• Adjust fluids or add boluses as needed

5. Post-op reassessment

• Check glucose and sodium before full recovery
• Consider continued isotonic fluids if extended fasting is expected

Recommendations 

For hospitals and anesthetists:

• Adopt balanced isotonic solutions with 1% glucose as standard for infants
• Train staff in correct dosing and monitoring protocols
• Phase out hypotonic high-glucose fluids to minimize sodium-related risks

For researchers:

• Investigate optimal fluid choices in special populations (preterms, neonates, endocrine disorders)
• Explore longer-term effects on recovery and neurological outcomes

Final thoughts

This comprehensive prospective study underscores a pivotal shift in pediatric anesthesia toward safer, smarter fluid choices tailored to the unique metabolic demands of infants. With compelling evidence that 1% glucose-balanced electrolyte solutions effectively safeguard against intraoperative hypoglycemia and electrolyte imbalance, clinicians have a validated, evidence-backed foundation for updating protocols.

For more detailed information, refer to the full article in British Journal of Anaesthesia
Reference: Lindestam U, Norberg Å, Frykholm P, Rooyackers O, Andersson A, Fläring U. Balanced electrolyte solution with 1% glucose as intraoperative maintenance fluid in infants. Response to Br J Anaesth 2025; 135: 798-9. Br J Anaesth. 
For more literature updates in pediatric anesthesia, read NYSORA’s Pediatric Anesthesia Updates 2025!