IV Drip (Intravenous Fluid Therapy) in Newborns

1. Why Newborns Often Need IV Fluids

• Inability to feed orally (prematurity, respiratory distress, surgical conditions, hypoglycemia)
• Maintenance of hydration while enteral feeding is being established
• Medication delivery (antibiotics, inotropes, etc.)
• Correction of electrolyte imbalances or hypoglycemia
• Perioperative fluid replacement

2. Access Sites

• Dorsum of hand, feet, antecubital fossa, or scalp veins (scalp veins common in neonates)
• Use 24-gauge cannulae in term newborns; 26-gauge in very premature infants

• Available in the first 7-10 days of life through the umbilical vein
• Preferred for central access in neonatal resuscitation and NICU admission
• Can be used to give glucose, medications, and TPN

• Umbilical artery - used for continuous blood pressure monitoring and blood gas sampling

• Emergency access if IV/UVC not obtainable (e.g., during resuscitation)

3. Fluid Requirements by Day of Life

• Barash Clinical Anesthesia 9e, p. 3584-3585
• Miller's Anesthesia 10e, p. 10617

4. Fluid Type

Maintenance Fluid

• Standard: 10% Dextrose + 0.2% NaCl + 20 mmol/L KCl for the first 48 hours
• Reason for sodium: The neonatal distal tubule cannot fully respond to aldosterone, causing obligate sodium losses - IV fluids must contain sodium to avoid hyponatremia
• After 48-72 hours: term infants may tolerate 5% Dextrose instead of 10%; preterm infants often need the higher glucose load longer
• Hypotonic solutions alone are contraindicated for replacing blood/ECF losses - they cause hyponatremia and hypovolemia

Replacement Fluid (blood loss, ECF losses, surgery)

• Use near-isotonic solutions: Lactated Ringer's (LR) or PlasmaLyte
• These match the electrolyte composition of ECF

Colloids

• Albumin 5% is traditionally used as the plasma expander of choice in neonates
• Synthetic colloids (HES, gelatin) have been used but safety data in neonates remain limited
• Barash Clinical Anesthesia 9e, p. 3585

5. Glucose Management

• Neonates are prone to hypoglycemia (especially: premature infants, infants of diabetic mothers, SGA, those receiving continuous glucose infusions that are abruptly stopped)
• Glucose infusion rate (GIR) is typically maintained at 4-6 mg/kg/min in stable term neonates; preterm infants may need 6-8 mg/kg/min
• D10W at 60 mL/kg/day ≈ 4.2 mg/kg/min GIR; at 80 mL/kg/day ≈ 5.6 mg/kg/min
• Monitor blood glucose regularly, especially perioperatively
• Iatrogenic hyperglycemia from excess dextrose can augment ischemic brain injury - balance is key; however, in cardiac surgery neonates, avoiding hypoglycemia takes precedence

6. Electrolytes

• Serum potassium may be 1-2 mmol/L higher than adult normal in the first 2 days (physiological)
• Sodium supplementation is added from Day 2-3 onward; avoid in first 24 hours due to post-birth natriuresis
• Calcium supplementation is needed in preterm infants and those at risk of hypocalcemia
• Monitor: Na, K, glucose, urine output (target ≥ 1-2 mL/kg/hr after Day 1)

7. Physiological Considerations Specific to Newborns

• Blood volume: ~90 mL/kg in term newborns, ~100 mL/kg in preterm/VLBW
• Barash Clinical Anesthesia 9e, p. 3583-3585

8. Monitoring

9. Special Scenarios

• Neonatal surgery: Replace ongoing losses with isotonic fluids (LR/PlasmaLyte); abdominal surgery losses can exceed 50 mL/kg/hr
• Resuscitation: UVC is the fastest reliable central access; intraosseous is the emergency backup
• TPN: For neonates who cannot receive enteral feeds; provides amino acids, lipids, glucose, electrolytes, vitamins

1. Start low (60 mL/kg/day Day 1), increase daily to 150 mL/kg/day by Day 7
2. Use glucose-containing solutions with sodium (not plain dextrose, not hypotonic saline alone)
3. Monitor glucose closely, especially in at-risk groups
4. Prefer isotonic solutions (LR, PlasmaLyte) for any volume replacement
5. Preterm infants need more fluid and more careful monitoring than term newborns

Direct Answer: Is 80 mL Isotonic Fluid Over 4 Hours Safe in a 3-Day-Old?

Step 1 - Calculate the Projected Daily Rate

Step 2 - Compare to Allowed Daily Maintenance

What 80 mL in 4 Hours Could Be Acceptable As

• Neonatal shock/resuscitation bolus is typically 10-20 mL/kg of isotonic fluid given over 30-60 minutes
• For a 3 kg baby: 10 mL/kg = 30 mL, 20 mL/kg = 60 mL - given once, rapidly, not over 4 hours
• Even as a bolus, 80 mL (= ~27 mL/kg for a 3 kg baby) at that rate would need to be justified by a clear clinical picture of severe hypovolemia/shock

What the Correct Maintenance Rate Looks Like for a 3-Day-Old

• Total daily fluid = 90 mL/kg × 3 kg = 270 mL/day
• Hourly rate = 270 ÷ 24 = ~11.25 mL/hr
• Over 4 hours = 11.25 × 4 = ~45 mL (not 80 mL)

Why Fluid Overload is Especially Dangerous in Neonates

1. Immature kidneys - GFR is low at Day 3; excess water cannot be excreted efficiently
2. Large ECF volume - The newborn is already in the process of normal post-birth diuresis; adding excess fluid disrupts this
3. Pulmonary consequences - Overload causes pulmonary edema, worsens respiratory distress
4. Risk of patent ductus arteriosus (PDA) - Fluid overload is a well-known trigger for symptomatic PDA in preterm neonates
5. Hyponatremia - Excess isotonic volume can dilute sodium in the face of impaired excretion
6. IVH risk in preterm infants - Rapid volume shifts increase risk of intraventricular hemorrhage

Bottom Line

Acute Kidney Injury (AKI) in the Newborn

1. Overview

• GFR is very low at birth and matures slowly over weeks
• Tubular function is immature (poor ability to concentrate/dilute urine, obligate sodium losses)
• The kidney cannot efficiently handle excess fluid, electrolytes, or nephrotoxins

2. Definition (Modified KDIGO for Neonates)

KDIGO Staging for Neonates

3. Causes - The Three Categories

A. Prerenal (Most Common, ~70%)

• Hypovolemia (fluid losses, hemorrhage, dehydration)
• Perinatal asphyxia / hypoxia-ischemia (HI)
• Sepsis / septic shock
• Cardiac failure / congenital heart disease (CHD)
• Patent ductus arteriosus (PDA) - reduces renal perfusion
• Necrotizing enterocolitis (NEC)
• High mean airway pressure (impairs venous return)
• Twin-to-twin transfusion syndrome (donor twin)
• ECMO

B. Intrinsic Renal (Intrinsic damage to kidney parenchyma)

• Acute tubular necrosis (ATN) - most common intrinsic cause; follows prolonged prerenal or nephrotoxin exposure
• Nephrotoxic medications: aminoglycosides (gentamicin), vancomycin, NSAIDs (indomethacin, ibuprofen - close PDA but impair renal blood flow), amphotericin B, acyclovir, contrast agents
• Renal vein thrombosis (presents with hematuria, thrombocytopenia, flank mass)
• Congenital renal anomalies (polycystic kidney disease, renal dysplasia)
• Perinatal asphyxia - direct tubular ischemic injury

C. Postrenal (Obstructive)

• Posterior urethral valves (PUV) - most common obstructive cause, males only
• Ureteropelvic junction (UPJ) obstruction
• Bilateral hydronephrosis
• Urethral atresia, prune belly syndrome

4. Risk Factors for Neonatal AKI

5. Clinical Features

• Oliguria - urine output <1 mL/kg/hr (most sensitive early sign); anuria may be present
• Edema - periorbital, peripheral, or generalized; fluid overload
• Hypertension - due to fluid/sodium retention
• Electrolyte abnormalities:
  • Hyperkalemia (dangerous - can cause arrhythmias)
  • Hyponatremia (dilutional)
  • Hyperphosphatemia
  • Hypocalcemia
  • Metabolic acidosis
• Elevated SCr and BUN (azotemia)
• Signs of underlying cause - pallor (sepsis), respiratory distress, abdominal distension (NEC/obstruction)

6. Investigations

FENa (Fractional Excretion of Sodium) in Neonates

• FENa = (urine Na × plasma Cr) ÷ (plasma Na × urine Cr) × 100
• Prerenal: FENa <2-3% in term; <5% in preterm
• Intrinsic ATN: FENa >3% in term; >5% in preterm
• (Note: FENa is normally higher in preterm neonates due to immature tubular reabsorption - interpret carefully)

7. Management

Step 1 - Treat the Underlying Cause

• Restore perfusion (fluid resuscitation for prerenal) - isotonic bolus 10-20 mL/kg over 30-60 min
• Treat sepsis (antibiotics - choose least nephrotoxic regimen)
• Relieve obstruction (urinary catheter, urology consult for PUV)
• Stop nephrotoxic drugs

Step 2 - Fluid Management

• If hypovolemic (prerenal): fluid challenge 10-20 mL/kg isotonic saline or LR
• If euvolemic/hypervolemic (intrinsic/established AKI): fluid restrict to insensible losses (~30-50 mL/kg/day) + urine output replacement only
• Strict input/output records and daily weights are mandatory
• Avoid fluid overload - it is independently associated with mortality

Step 3 - Electrolyte Management

Step 4 - Nutritional Support

• Ensure adequate caloric intake despite fluid restriction
• Adjust formula concentration or TPN
• Dietitian consultation for fluid-restricted neonates

Step 5 - Drug Dose Adjustment

• All renally-cleared drugs must have doses/intervals adjusted
• Aminoglycosides: extend dosing interval, monitor drug levels
• Avoid NSAIDs, contrast agents, nephrotoxic combinations

Step 6 - Dialysis / Renal Replacement Therapy (RRT)

• Severe refractory hyperkalemia
• Fluid overload unresponsive to diuretics
• Severe metabolic acidosis
• Uremic symptoms (encephalopathy, pericarditis)
• SCr ≥2.5 mg/dL persistent

• Peritoneal dialysis (PD) - first choice in most neonatal centers; catheter inserted surgically; well-tolerated even in small/preterm infants
• Continuous renal replacement therapy (CRRT) - for hemodynamically unstable neonates; requires specialized equipment and vascular access; used in larger/more stable NICUs
• Hemodialysis is rarely used in neonates due to technical difficulty

8. Diuretics in Neonatal AKI

• Furosemide: often used to convert oliguric to non-oliguric AKI and to manage fluid overload
• Does NOT improve outcomes or reduce need for dialysis - used for fluid management, not to treat AKI itself
• Dose: 1-2 mg/kg IV; can be given as continuous infusion in severe fluid overload
• Use only after adequate volume status is confirmed (not in prerenal AKI)

9. When to Consult Nephrology

• AKI stage 2-3 (KDIGO)
• SCr ≥2.5 mg/dL persisting beyond 3 days
• Need for dialysis
• Suspected structural renal anomaly
• Refractory electrolyte disturbances

10. Prognosis and Follow-up

• Most prerenal AKI resolves with treatment of the underlying cause
• ATN may take days to weeks to recover
• Long-term risk: neonatal AKI - even if resolved - is associated with:
  • CKD in childhood and adulthood
  • Hypertension
  • Reduced nephron mass (especially in preterm)
• Recommended follow-up:
  • 3-6 months post-discharge for AKI requiring dialysis
  • 6-12 months for preterm/SGA infants with severe AKI (SCr ≥2.5 mg/dL)
  • Annual BP and creatinine checks thereafter