Feeding Guidelines for Extremely Low Birth Weight (ELBW) Infants
ELBW infants should receive a gradual increase in fluid intake starting at 80-100 ml/kg/day on day 1, increasing to 160-180 ml/kg/day by day 5, with early introduction of minimal enteral nutrition to promote gastrointestinal development. 1, 2
Fluid Management by Phase
Phase I (Transition Phase - First 5 Days)
- Initial fluid requirements for ELBW infants (<1000g) should be 80-100 ml/kg/day on day 1, gradually increasing to 160-180 ml/kg/day by day 5 3, 1
- Expected weight loss should be 7-10% of birth weight during this phase 3, 1
- Electrolytes should be started during this phase with sodium and potassium supplementation beginning on day 1 when providing high amino acid and energy supply 3, 1
- Chloride intake should be slightly lower than the sum of sodium and potassium intakes (Na + K - Cl = 1-2 mmol/kg/day) to avoid iatrogenic metabolic acidosis 3
- Monitor for nonoliguric hyperkalemia when initiating potassium supplementation in ELBW infants 1
Phase II (Intermediate Phase - Return to Birth Weight)
- Birth weight should typically be regained by 7-10 days of life 3, 1
- Maintain fluid intake at 140-160 ml/kg/day 3, 1
- Sodium requirements: 2-5 mmol/kg/day (up to 7 mmol/kg/day in some cases) 3
- Potassium requirements: 1-3 mmol/kg/day 3
Phase III (Stable Growth Phase)
- Maintain fluid intake at 140-160 ml/kg/day 3, 1
- Sodium requirements: 3-5 mmol/kg/day 3, 1
- Potassium requirements: 2-5 mmol/kg/day 3, 1
Enteral Feeding Guidelines
Minimal Enteral Nutrition (MEN)
- Initiate minimal enteral nutrition as early as possible, even in ventilated ELBW infants 2
- MEN improves gastrointestinal enzyme activity, hormone release, blood flow, motility, and microbial flora 2
- Clinical benefits include improved milk tolerance, greater postnatal growth, reduced systemic sepsis, and shorter hospital stay 2, 4
Advancement of Feeds
- Daily increments of 15-24 ml/kg/day are considered slow advancement 5
- Daily increments of 30-40 ml/kg/day are considered faster advancement 5
- Evidence suggests that slow advancement of enteral feed volumes compared to faster rates does not reduce the risk of NEC but may slightly increase the risk of invasive infection 5
Feeding Type
- Breast milk is preferred over formula for ELBW infants 4
- Breast milk is associated with better weight gain (average 120.83g/week vs 97.27g/week with formula) and lower incidence of infection (66.6% vs 100% with formula) 4
- Formula feeding is associated with increased risk of NEC in ELBW infants 4
Feeding Frequency
- 2-hour feeding intervals may be advantageous compared to 3-hour intervals 6
- 2-hour feeding intervals are associated with shorter duration of CPAP support and phototherapy compared to 3-hour intervals 6
- Time to full enteral feeding and growth parameters are similar between 2-hour and 3-hour feeding regimens 6
Monitoring Parameters
- Track daily weight changes to assess fluid status 1
- Monitor serum electrolyte concentrations regularly, with frequency based on clinical status 1
- Ensure urine output remains adequate (>1 ml/kg/hour) 1
- Monitor for signs of feeding intolerance and NEC 5, 4
Special Considerations
- Environmental factors significantly impact fluid requirements:
- Double wall incubators reduce insensible water loss in VLBW neonates by about 30% when a humidity of 90% is used at thermo-neutral temperature 3
Pitfalls to Avoid
- Excessive fluid administration can lead to patent ductus arteriosus, necrotizing enterocolitis, and bronchopulmonary dysplasia 3, 1
- Inadequate fluid administration may result in electrolyte disturbances and dehydration 3, 1
- High chloride loads can cause hyperchloremic metabolic acidosis 3, 1
- Delaying enteral nutrition may increase risk of infection and prolong hospital stay 2, 5
- Formula feeding increases risk of NEC and infection compared to breast milk feeding 4