Why Nutrition Matters in Surgery
Nutrition influences every stage of the surgical journey. Adequate protein and energy stores support wound healing, preserve immune function, and reduce complications such as infection, delayed gastric emptying, and loss of muscle mass. Conversely, malnutrition or overnutrition increases the risk of postoperative morbidity, prolongs hospital stay, and raises healthcare costs.
Preoperative Nutritional Assessment
Systematic screening should be performed for all surgical candidates, ideally 24 weeks before the procedure.
- Screening tools: NRS2002, MUST, or the Malnutrition Universal Screening Tool.
- Key parameters: BodyMass Index (BMI), recent weight loss (>5% in 36months), serum albumin/prealbumin, and functional status (handgrip strength).
- Identify risk groups: Elderly, chronic disease (e.g., COPD, CHF, renal failure), cancer, and patients with gastrointestinal disorders.
Preoperative Nutrition Strategies
1. Oral Nutritional Supplements (ONS)
Highprotein, energydense ONS (400600kcal/day) for 714days before surgery can improve nitrogen balance and reduce infection rates.
2. Immunonutrition
Formulas containing arginine, omega3 fatty acids, and RNA have shown benefit in major abdominal surgery, decreasing postoperative complications by 2030%.
3. Carbohydrate Loading
1520g of carbohydrate in a clear liquid taken 2hours before anesthesia reduces insulin resistance and improves patient comfort.
4. Fasting Guidelines
Current ERAS recommendations:
- Clear liquids up to 2hours before induction.
- Solid foods up to 6hours before, unless a specific condition dictates otherwise.
Intraoperative Nutrition Management
While most patients receive no nutrition during surgery, specific practices can mitigate metabolic stress:
- Glucose control: Maintain blood glucose 140180mg/dL using insulin infusion when needed.
- Intravenous (IV) fluids: Use balanced electrolyte solutions; add dextrose (5%) for prolonged cases to supply minimal calories.
- Early enteral access: For highrisk or long procedures, place a feeding tube intraoperatively to enable postoperative feeding within 1224hours.
Postoperative Nutrition
1. Early Enteral Feeding
Begin oral intake or enteral nutrition (EN) within 24hours for most patients. Early EN preserves gut integrity, reduces bacterial translocation, and promotes anabolism.
2. Determining Route
| Condition | Preferred Route | Rationale |
|---|---|---|
| Intact gastrointestinal tract | Oral/Oralsupplemented EN | Physiologic and costeffective |
| Postgastrointestinal surgery with delayed motility | Nasogastric or postpyloric tube | Allows controlled delivery |
| Severe ileus or high output fistula | Parenteral nutrition (PN) | Meets needs when gut unusable |
3. Protein Targets
2530g of highquality protein per meal, aiming for 1.21.5gkgday in most patients; up to 2.0gkgday in catabolic states (e.g., trauma, major burns).
4. Caloric Goals
2530kcalkgday after the first 48hours, adjusted for obesity (use ideal body weight) or underweight (use actual weight).
5. Immunonutrition Postop
Continue immunomodulating formulas for 57days after major abdominal or oncologic surgery to further reduce infectious complications.
Special Populations
Elderly Patients
Higher prevalence of sarcopenia; aim for protein 1.5gkgday and include leucinerich supplements. Monitor for delirium related to hypoglycemia.
Obese Patients
Use hypocaloric, highprotein feeding (0.8kcalkgday of ideal body weight) to preserve lean mass while avoiding overfeeding.
Diabetic Patients
Provide carbohydratecontrolled meals (4555% of calories) with low glycemic index; frequent glucose checks; consider basalbolus insulin regimen.
Patients with Malignancy
Preoperative ONS with omega3 fatty acids; postoperative continuation of immunonutrition for up to 2weeks to support recovery and reduce chemotherapy delays.
Key Takeaways
- Screen every surgical patient for nutritional risk early.
- Implement evidencebased preoperative strategies: oral supplements, immunonutrition, and carbohydrate loading.
- Follow ERAS fasting guidelinesclear liquids up to 2h before anesthesia.
- Prioritize early enteral nutrition postoperatively; reserve parenteral nutrition for specific indications.
- Tailor protein and calorie targets to the individuals metabolic state and comorbidities.
- Use specialized protocols for elderly, obese, diabetic, and oncologic patients.
