Volume Replacement

• Post-Aggression Metabolism:
  • Metabolic changes following trauma, surgery, or acute illness.
• Phases of Post-Aggression Metabolism (Cuthbertson):
  • Phase I (Acute Phase):
    • Duration: 1 hour to 1 day.
    • Catabolic state with reduced insulin effect and predominance of anti-insulin factors (adrenaline, glucocorticoids, ADH, glucagon).
    • Features: Hyperglycemia, lipolysis, protein catabolism, increased nitrogen loss, potassium excretion, and sodium retention.
    • Therapy: Water and electrolyte balance; no enteral or parenteral nutrition.
  • Phase II (Transition Phase):
    • Duration: Up to several weeks.
    • Therapy: Gradual initiation of parenteral nutrition.
  • Phase III (Reparation Phase):
    • Duration: Weeks.
    • Anabolic state.
    • Therapy: Enteral or oral nutrition.
• High-calorie infusions are not effective during Phase I as the body cannot metabolize them.
• Daily Fluid Requirements:
  • Basal: 30 ml/kg body weight.
  • Moderate: 50 ml/kg body weight.
  • High: 100–150 ml/kg body weight.
• Fluid Balance Monitoring:
  • Central venous pressure (2–12 cm H₂O as normal range).
  • Body weight and urine output.
  • Fluid intake measurements.
  • Body temperature adjustments (500 ml per 1°C increase).
  • Circulatory parameters (e.g., blood pressure, heart rate, pulmonary catheter readings).
  • Laboratory values (e.g., hemoglobin, hematocrit, electrolytes, creatinine, serum osmolality).
• Indications:
  • Preoperative: Volume deficits in older patients or those with gastrointestinal tumors, ileus, etc.
  • Intraoperative: Replacement of losses based on the type and extent of surgery (managed by anesthetists).
  • Postoperative: Replacement of losses (e.g., perspiration, urine, drainage, fever) and maintenance requirements.

Infusion Solutions

• Crystalloid Infusion Solutions:
  • Require 3–4 times the volume of the deficit due to low volumetric effect.
• Full Electrolyte Solutions:
  • Sodium content similar to plasma (130–154 mmol/l).
  • Examples: Ringer’s solution, Ringer-lactate, Ringer-acetate, normal saline (0.9% NaCl).
  • Indications: Volume replacement, drug infusion, maintaining venous access.
• Half/Third Electrolyte Solutions:
  • Sodium content about half or one-third of plasma.
  • Examples: Sterofundin HEG-5, Sterofundin BG-5.
  • Indications: Infusion/nutrition therapy.
• 5% Glucose Solution:
  • No sodium, low volumetric effect.
  • Indications: Carrier solution for drugs, parenteral nutrition.
• Colloidal Infusion Solutions:
• Iso-oncotic Solutions:
  • Plasma replacement solutions (e.g., HAES 6%) with a volumetric effect equal to infused volume.
• Hyper-oncotic Solutions:
  • Plasma expanders (e.g., HAES 10%) draw fluid from interstitial to intravascular spaces.

Parenteral Nutrition

• Indications:
  • Immediate postoperative nutritional needs or poor preoperative status.
  • Conditions preventing enteral nutrition (e.g., acute pancreatitis, sepsis).
• Contraindications:
  • Severe metabolic derangements, shock, multi-organ failure.
• Complications:
  • Hyperglycemia, hepatic steatosis, cholestasis, gut atrophy, electrolyte imbalances.
• Energy Needs:
  • 25–30 kcal/kg/day; higher in sepsis or burns.
• Nutrient Composition:
  • Carbohydrates: 50%.
  • Fats: 25–30%.
  • Amino acids: 20–25%.
  • Vitamins, electrolytes, trace elements, and water.

Enteral Nutrition

• Advantages:
  • Lower cost, reduced complication rates, physiological approach.
• Indications:
  • Chronic swallowing disorders, inadequate oral intake, mechanical obstruction.
• Contraindications:
  • Ileus, resistant vomiting, acute GI bleeding, reduced absorption area.
• Complications:
  • Aspiration, diarrhea, tube obstruction, pressure ulcers.
• Nutritional Solutions:
  • Standard caloric solutions: 1 kcal/ml.
  • High-caloric solutions: 1.5 kcal/ml.
• Application Methods:
  • Bolus Feeding: Incremental doses (e.g., 6×50 ml on Day 1).
  • Continuous Feeding: Using feeding pumps for steady administration.
• Monitoring:
  • Regular evaluation of weight, blood sugar, electrolytes, and liver function tests.