PEDIATRIC SURGERY Tables and scores

Fluids, Electrolytes, and Nutrition in Pediatric Surgery

Fluid and Electrolyte Balance

• Assessment is crucial in pediatric surgical patients, especially neonates with a narrow margin for error.

Fluid Requirements

• Premature Infants:
  • Higher insensible water losses due to thin immature skin barrier.
  • Insensible water losses based on gestational age:
    • 45-60 mL/kg/day for infants <1500 g.
    • 30-35 mL/kg/day for term infants.
• Additional Fluid Losses:
  • Radiant heat warmers.
  • Phototherapy for hyperbilirubinemia.
  • Respiratory distress.
• Physiologic Water Loss:
  • First 3-5 days of life: up to 10% of body weight.

Calculating Fluid Requirements

• Based on Body Weight.
• Initial Days:
  • Conservative fluid recommendations.
• By Fourth Day of Life:
  • Maintenance Fluids: 100-130 mL/kg/day.
• Surgical Conditions:
  • Gastroschisis.
  • Necrotizing Enterocolitis (NEC).
  • Require significantly higher volumes.

Monitoring Fluid Status

• Indicators of Adequate Tissue Perfusion:
  • Urine Output:
    • Minimum: 1-2 mL/kg/day in a newborn.
  • Osmolarity:
    • Prerenal Azotemia response: Concentrate urine up to ~700 mOsm/kg.

Electrolyte Requirements

• Sodium:
  • 2-4 mEq/kg/day.
• Potassium:
  • 1-2 mEq/kg/day.
• Typical Replacement Solutions:
  • 5% Dextrose in 0.45% Normal Saline.
  • 20 mEq/L Potassium.
  • Administered at calculated maintenance rate.

Replacement of Fluid Losses

• Sources of Fluid Loss:
  • Gastric Drainage.
  • Ostomy Output.
  • Diarrhea.
• Replacement Strategies:
  • Gastric Losses:
    • Replace with equal volumes of 0.45% Normal Saline + 20 mEq/L Potassium.
  • Diarrheal, Pancreatic, and Biliary Losses:
    • Replace with isotonic Lactated Ringer solution.

Management of Hypovolemia

• Cause: Acute Hemorrhage.
• Correction:
  • Prompt transfusion of blood products.
  • Bolus:
    • 10-20 mL/kg of:
      • Packed Red Blood Cells.
      • Plasma.
      • 5% Albumin.

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Congenital Pulmonary Airway Malformation (CPAM)

Definition

• CPAMs are hamartomatous lesions where a multicystic mass replaces normal lung tissue.
• Connection:
  • Linked to the tracheobronchial tree.
  • Blood supply is pulmonary.

Potential Complications

• Malignant Transformation:
  • Can transform into rhabdomyosarcoma in older children.
• Associated Risks:
  • Pleuropulmonary Blastoma.

Classification

• Based on Imaging Appearance:
  • Stocker Classification:
    • Type I:
      • 75% of cases.
      • Large cysts: 2-10 cm.
      • Effects: Can compress normal lung parenchyma.
    • Type II:
      • Numerous small cysts: <1 cm in diameter.
    • Type III:
      • Rare.
      • Very small cysts: Only a few millimeters.
      • Associated with:
        • Mediastinal shift.
        • Hydrops.
        • Poor prognosis.

Diagnosis

• Prenatal Detection:
  • Fetal MRI: Differentiates CPAM from other thoracic anomalies.
• Postnatal Diagnosis:
  • Chest Radiograph:
    • Cystic thoracic mass.
    • May show air-fluid levels.
  • Ultrasound and CT Studies: Routinely obtained for confirmation.
• Pathologic Examination: Confirms diagnosis.

Management

Prenatal Management

• If Fetal Distress Occurs:
  • Fetal Thoracotomy.
  • Thoracoamniotic Shunting (if fetus is <32 weeks).
  • Note: Extremely rare.
• Expectant Management:
  • Partial regression often occurs in the third trimester.
  • Betamethasone:
    • Single course effective in:
      • Promoting spontaneous regression.
      • Size reduction.
      • Resolving hydrops.

Postnatal Management

• Surgical Intervention:
  • Resection of the involved lobe recommended due to:
    • Risk of infection.
    • Malignant transformation.
  • Timing:
    • Elective resection typically at 3-6 months of age.
    • Variability exists among surgeons regarding ideal timing for asymptomatic CPAM.

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Anatomic Variants of Esophageal Atresia with Tracheoesophageal Fistula (TEF)

1. First Variant (7%):
   • Isolated esophageal atresia.
   • No connection between the esophagus and trachea.
   • Occurs in 7% of cases.
2. Second Variant (2%):
   • Isolated tracheoesophageal fistula without esophageal atresia.
   • The esophagus is intact.
   • Occurs in 2% of cases.
3. Third Variant (86%):
   • The most common variant.
   • PROXIMAL Esophageal atresia with a distal tracheoesophageal fistula.
   • Occurs in 86% of cases.
4. Fourth Variant (1%):
   • Esophageal atresia with both proximal and distal tracheoesophageal fistulas.
   • Occurs in 1% of cases.
5. Fifth Variant (4%):
   • Esophageal atresia with a proximal tracheoesophageal fistula.
   • Occurs in 4% of cases

Classification of Jejunoileal Atresia (Types I-IV)

1. Type I:
   • A mucosal web or diaphragm obstructs the bowel.
2. Type II:
   • An atretic cord between two blind ends of bowel.
   • The mesentery is intact.
3. Type IIIa:
   • Complete separation of the blind ends of bowel.
   • A V-shaped mesenteric gap exists between them.
4. Type IIIb (Apple Peel/Christmas Tree Deformity):
   • Involves a large mesenteric gap.
   • The distal bowel receives retrograde blood supply from the ileocolic or right colic artery.
   • Risks:
     • Anastomotic failures.
     • Ischemic necrosis from volvulus.
     • Reduced intestinal length in many infants with this type.
5. Type IV:
   • Multiple atresias.
   • A "string of sausage" appearance.

National Wilms Tumor Study Group Staging System

Stage	Definition
I	Tumor is limited to the kidney and completely excised without rupture or biopsy. The surface of the renal capsule is intact.
II	Tumor extends through the renal capsule but is completely removed with no microscopic involvement of the margins. Tumor may involve vessels outside the kidney. Includes cases with local spillage of tumor limited to the tumor bed or where a biopsy was performed before removal.
III	Residual tumor is confined to the abdomen and involves nonhematogenous spread, including abdominal lymph nodes, diffuse peritoneal contamination, peritoneal implants, or grossly/microscopically positive resection margins.
IV	Hematogenous metastases present at any site.
V	Bilateral renal involvement.

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