What is the initial fluid management strategy for acute kidney injury (AKI) in neonates?

Initial Fluid Management for Acute Kidney Injury in Neonates

Isotonic crystalloids should be used as the first-choice fluid for initial resuscitation in neonates with acute kidney injury (AKI), administered at 10-20 ml/kg and repeated based on individual clinical response. 1, 2

Initial Fluid Resuscitation Strategy

• Use isotonic crystalloids rather than colloids (albumin or starches) for initial management of intravascular volume expansion in neonates at risk for or with AKI 1, 2
• Initial fluid volume should be 10-20 ml/kg, with repeated doses based on individual clinical response 1
• Avoid overzealous fluid resuscitation as it may worsen outcomes and contribute to fluid overload 2
• Consider balanced electrolyte solutions when appropriate to avoid hyperchloremic metabolic acidosis that can occur with normal saline 2
• In cases of hemorrhagic shock, packed red blood cells can be transfused in newborns with hemoglobin <12 g/dL 1

Monitoring Fluid Status

• Fluid overload is associated with worse outcomes in neonates with AKI 3, 4
• Neonates with >30% fluid overload at the time of continuous renal replacement therapy (CRRT) initiation have lower survival rates 4
• Monitor for therapeutic endpoints including:
  • Capillary refill ≤2 seconds 1
  • Normal pulses with no differential between peripheral and central pulses 1
  • Warm extremities 1
  • Urine output >1 mL/kg/h 1
  • Normal blood pressure for age 1

Vasopressor Support

• Implement vasopressors in conjunction with fluids in neonates with vasomotor shock who have or are at risk for AKI 1, 2
• For neonates not responding to initial fluid resuscitation, consider:
  • Low-dose dopamine (<8 μg/kg/min) combined with dobutamine (up to 10 μg/kg/min) as first-line agents 1
  • If inadequate response, epinephrine (0.05–0.3 μg/kg/min) can be added to restore normal blood pressure and perfusion 1
  • Norepinephrine can be effective for refractory hypotension but maintain ScvO2 >70% 1

Diuretic Management

• Do not use diuretics to prevent AKI 1, 2
• Diuretics should only be used for management of volume overload in established AKI 1, 2
• Diuretics or CRRT is recommended in newborns who are 10% fluid overloaded and unable to attain fluid balance with native urine output/extrarenal losses 1

Special Considerations

• In neonates with severe perinatal asphyxia at high risk for AKI, administer a single dose of theophylline which improves fluid control and GFR in the first week of life 1, 2
• Avoid nephrotoxic medications when possible, particularly aminoglycosides unless no suitable alternatives are available 1, 2
• If aminoglycosides must be used, administer as a single daily dose rather than multiple-dose daily regimens 1, 2
• When calculating fluid requirements, consider that fluid correction affects serum creatinine measurements and may mask AKI diagnosis 5
• Maintain adequate nutrition with 2-3 g/kg/d protein for infants aged 0-2 years with AKI and target total energy intake of 20-30 kcal/kg/d 1, 2

Pitfalls to Avoid

• Failing to correct serum creatinine for fluid balance may underestimate the prevalence and impact of AKI in neonates 5
• Using colloids as first-line fluid therapy (unless in hemorrhagic shock) 1
• Using low-dose dopamine, fenoldopam, or atrial natriuretic peptide specifically to prevent or treat AKI 2
• Restricting protein intake with the aim of preventing or delaying initiation of renal replacement therapy 2

By following these evidence-based guidelines for fluid management in neonatal AKI, clinicians can optimize outcomes while minimizing complications related to fluid overload and electrolyte disturbances.