SURGICAL NUTRITION

1. SURGICAL NUTRITION • Awadh AlqahtaniMD,MSc,FRCSC(surgery)FRCSC(oncology) • FISC • Surgical oncologist and laparoscopic Bariatric surgeon • 22/9/2014

2. Lecture Outline • Energy Sources • Nutrition Requirements • Diet Advancement • Micronutrients for wound healing • Enteral versus Parenteral Nutrition • Case studies

3. Energy Sources • Carbohydrates • Limited storage capacity, needed for CNS function • Yields 3.4 kcal/gram • Pitfall: too much=lipogenesis and increased CO2 production • Fats • Major endogenous fuel source in healthy adults • Yields 9 kcal/gm • Pitfall: too little=essential fatty acid (linoleic acid deficiency-dermatitis and increased risk of infections • Protein • Needed to maintain anabolic state (match catabolism) • Yields: 4 kcal/gm • Pitfall: must adjust in patient with renal and hepatic failure • Elevated creatinine, BUN, and/or ammonia

4. Nutrition Requirements • Healthy Adults • Calories: 25-35 kcals/kg • Protein: 0.8-1 gm/kg • Fluids: 30 mls/kg • Requirement Change for the Surgical Patient • Special Considerations • Stress • Injury or disease • Surgery • Pre-hospital/pre-surgical nutrition

5. Nutrition • The surgical patient… • Extraordinary stressors (hypovolemia, hypervolemia, bacteremia, medications) • Wound Healing • Anabolic state, appropriate vitamins (A, C, Zinc), and adequate kcals/protein. • Poor Nutrition=Poor Outcomes • For every gram deficit of untreated hypoalbuminemia there is ~30% increase in mortality

6. Post-Operative Nutrition Requirements • Calories: • Increase to 30-40 kcals/kg • Patient on ventilator usually require less calories ~20-25 kcal/kg • Protein: • Increase to 1-1.8 grams/kg • Fluids: • Individualized

7. Diet Advancement • Traditional Method: • Start clear liquids when signs of bowel function returns. • Rationale: Clear liquid diets supply fluid and electrolytes in a form that require minimal digestion and little stimulation of the GI tract. • Clear liquids are intended for short-term use due to inadequacy

8. Diet Advancement • Recent Evidence: • Suggests that liquid diets and slow diet progression may not be warranted!! • Clinical study: • Looked atearly post-operative feedingusing regular diets or very fast progression vs. traditional methods of NPO until bowel function with slow diet progression and foundno difference in post-operative complications. (emesis, distention, NGT reinsertion, LOS,)

9. Micronutrients in Wound Healing • Vitamin Supplementation to promote healing has been somewhat disputed. • Some studies show no significant effect unless there is a clinical vitamin deficiency • Serum vitamin levels are not always accurate; therefore, must use subjective diet history and clinical judgment to determine deficiency.

10. Key Nutrients for Wound Healing • Vitamin A: • Cellular differentiation, proliferation, epithelialization, collagen synthesis, counteract catabolic effect of steroids. • RDA=3333 International Units • Appropriate dose=25,000 IU per day x 10 days in setting of high dose steroids or deficiency. • Avoid long term supplementation due to high risk of toxicity with fat-soluble vitamins. • No vitamin A with renal failure due to greater potent ional for toxicity. (Can exceed the binding capacity of retinol binding protein leading to elevated circulating levels.)

11. Key Nutrients for Wound Healing • Vitamin C: • Collagen synthesis • RDA=50-90 mg/day • Low levels are common in high risk population (elderly, smokers, cancer, liver disease). • Appropriate dose: 500 mg x 10 days • No vitamin C with renal failure due to risk for renal oxalate stone formation.

12. Key Nutrients for Wound Healing • Zinc: • Protein synthesis, cellular replication, collagen formation; large wounds, chest tubes, and wound drains contribute to further zinc loses. • Appropriate dose: 220 mg per day of Zinc Sulfate or 50 mg of elemental Zinc x 10 days. • Prolonged Zinc supplementation interferes with copper absorption and can lead to copper deficiency which delays wound healing by impairing collagen synthesis. • MVI with minerals: • 1 tablet daily to compensate for any general micronutrient losses.

13. What is nutrition support? • An alternate means of providing nutrients to people who cannot eat any or enough food • When is it needed? • Illness resulting in inability to take in adequate nutrients by mouth • Illness or surgery that results in malfunctioning gastrointestinal tract • Two types: • Enteral nutrition • Parenteral nutrition

14. Indications for Enteral Nutrition • Malnourished patient expected to be unable to eat adequately for > 5-7 days • Adequately nourished patient expected to be unable to eat > 7-9 days • Adaptive phase of short bowel syndrome • Following severe trauma or burns

15. Contraindications to Enteral Nutrition Support • Malnourished patient expected to eat within 5-7 days • Severe acute pancreatitis • High output enteric fistula distal to feeding tube • Inability to gain access • Intractable vomiting or diarrhea • Aggressive therapy not warranted • Expected need less than 5-7 days if malnourished or 7-9 days if normally nourished

16. Enteral Access Devices • Nasogastric • Nasoenteric • Gastrostomy • PEG (percutaneous endoscopic gastrostomy) • Surgical or open gastrostomy • Jejunostomy • PEJ (percutaneous endoscopic jejunostomy) • Surgical or open jejunostomy • Transgastric Jejunostomy • PEG-J (percutaneous endoscopic gastro-jejunostomy) • Surgical or open gastro-jejunostomy

17. Feeding Tube Selection • Can the patient be fed into the stomach, or is small bowel access required? • How long will the patient need tube feedings?

18. Gastric vs. Small Bowel Access • “If the stomach empties, use it.” • Indications to consider small bowel access: • Gastroparesis / gastric ileus • Recent abdominal surgery • Sepsis • Significant gastroesophageal reflux • Pancreatitis • Aspiration • Ileus • Proximal enteric fistula or obstruction

19. Short-Term vs. Long-Term Tube Feeding Access • No standard of care for cut-off time between short-term and long-term access • However, if patient is expected to require nutrition support longer than 6-8 weeks, long-term access should be considered

20. Choosing Appropriate Formulas • Categories of enteral formulas: • Polymeric (Jevity) • Whole protein nitrogen source, for use in patients with normal or near normal GI function • Monomeric or elemental (Perative, Optimental) • Predigested nutrients; most have a low fat content or high % of MCT oil (medium-chain triglycerides); for use in patients with severely impaired GI function • Disease specific (Nepro, Nutrahep, Glucerna) • Formulas designed for feeding patients with specific disease states • Formulas are available for respiratory disease, diabetes, renal failure, hepatic failure, and immune compromise *well-designed clinical trials may or may not be available

21. Enteral Nutrition Prescription Guidelines • Gastric feeding • Continuous feeding: • Start at rate 30 mL/hour • Advance in increments of 20 mL q 8 hours to goal • Check gastric residuals q 4 hours • Bolus feeding: • Start with 100-120 mL bolus • Increase by 60 mL q bolus to goal volume • Typical bolus frequency every 3-8 hours • Small bowel feeding • Continuous feeding only; do not bolus due to risk of dumping syndrome • Start at rate 20 mL/hour • Advance in increments of 20 mL q 8 hours to goal • Do not check gastric residuals

22. Aspiration Precautions • To prevent aspiration of tube feeding, keep HOB > 30° at all times • Do not use methylene blue to test for aspiration; regular blue food dye OK but not proven effective method of detecting aspiration

23. Complications of Enteral Nutrition Support • Nausea and vomiting / delayed gastric emptying • Malabsorption • Common manifestations include unexplained weight loss, steatorrhea, diarrhea • Potential causes include gluten sensitive enteropathy, Crohn’s disease, radiation enteritis, HIV/AIDS-related enteropathy, pancreatic insufficiency, short gut syndrome

24. Enteral Nutrition Case Study • 78-year-old woman admitted with new CVA • Significant aspiration detected on bedside swallow evaluation and confirmed with modified barium swallow study; speech language pathologist recommended strict NPO with alternate means of nutrition • PEG placed for long-term feeding access • Plan of care is to stabilize the patient and transfer her to a long-term care facility for rehabilitation

25. Enteral Nutrition Case Study (continued) • Height: 5’4” IBW: 120# +/- 10% • Weight: 130# / 59kg 100% IBW • BMI: 22 • Usual weight: ~130# no weight change • Estimated needs: • 1475-1770 kcal (25-30 kcal/kg) • 59-71g protein (1-1.2 g/kg) • 1770 mL fluid (30 mL/kg)

26. Steps to determine the Enteral Nutrition Prescription • Estimate energy, protein, and fluid needs • Select most appropriate enteral formula • Determine continuous vs. bolus feeding • Determine goal rate to meet estimated needs • Write/recommend the enteral nutrition prescription

27. Enteral Nutrition Prescription • Tube feeding via PEG with full strength Jevity 1.2 • Initiate at 30 mL/hour, advance by 20 mL q 8 hours to goal • Goal rate = 55 mL/hour continuous infusion • Above goal will provide 1584 kcal, 73g protein, 1069 mL free H2O • Give additional free H2O 175 mL QID to meet hydration needs and keep tube patent • Check gastric residuals q 4 hours; hold feeds for residual > 200 mL • Keep HOB > 30° at all times

28. What is parenteral nutrition? • Parenteral Nutrition • also called "total parenteral nutrition," "TPN," or "hyperalimentation." • It is a special liquid mixture given into the blood via a catheter in a vein. • The mixture contains all the protein, carbohydrates, fat, vitamins, minerals, and other nutrients needed.

29. Indications for Parenteral Nutrition Support • Malnourished patient expected to be unable to eat > 5-7 days AND enteral nutrition is contraindicated • Patient failed enteral nutrition trial with appropriate tube placement (post-pyloric) • Enteral nutrition is contraindicated or severe GI dysfunction is present • Paralytic ileus, mesenteric ischemia, small bowel obstruction, enteric fistula distal to enteral access sites

30. PPN vs. TPN • TPN (total parenteral nutrition) • High glucose concentration (15%-25% final dextrose concentration) • Provides a hyperosmolar formulation (1300-1800 mOsm/L) • Must be delivered into a large-diameter vein through central line. • PPN (peripheral parenteral nutrition) • Similar nutrient components as TPN, but lower concentration (5%-10% final dextrose concentration) • Osmolarity < 900 mOsm/L (maximum tolerated by a peripheral vein) • May be delivered into a peripheral vein • Because of lower concentration, large fluid volumes are needed to provide a comparable calorie and protein dose as TPN

31. Parenteral Access Devices • Peripheral venous access • Catheter placed percutaneously into a peripheral vessel • Central venous access (catheter tip in SVC) • Percutaneous jugular, femoral, or subclavian catheter • Implanted ports (surgically placed) • PICC (peripherally inserted central catheter)

32. Writing TPN prescriptions • Determine total volume of formulation based on individual patient fluid needs • Determine amino acid (protein) content • Adequate to meet patient’s estimated needs • Determine dextrose (carbohydrate) content • ~70-80% of non-protein calories • Determine lipid (fat) content • ~20-30% non-protein calories • Determine electrolyte needs • Determine acid/base status • Check to make sure desired formulation will fit in the total volume indicated

33. Parenteral Nutrition Monitoring • Check daily electrolytes and adjust TPN/PPN electrolyte additives accordingly • Check accu-check glucose q 6 hours (regular insulin may be added to TPN/PPN bag for glucose control as needed) • Non-diabetics or NIDDM: start with half of the previous day’s sliding scale insulin requirement in TPN/PPN bag and increase daily in the same manner until target glucose is reached • IDDM: start with 0.1 units regular insulin per gram of dextrose in TPN/PPN, then increase daily by half of the previous day’s sliding scale insulin requirement • Check triglyceride level within 24 hours of starting TPN/PPN • If TG >250-400 mg/dL, lipid infusion should be significantly reduced or discontinued • Consider adding carnitine 1 gram daily to TPN/PPN to improve lipid metabolism • ~100 grams fat per week is needed to prevent essential fatty acid deficiency

34. Parenteral Nutrition Monitoring (continued) • Check LFT’s weekly • If LFT’s significantly elevated as a result of TPN, then minimize lipids to < 1 g/kd/day and cycle TPN/PPN over 12 hours to rest the liver • If Bilirubin > 5-10 mg/dL due to hepatic dysfunction, then discontinue trace elements due to potential for toxicity of manganese and copper • Check pre-albumin weekly • Adjust amino acid content of TPN/PPN to reach normal pre-albumin 18-35 mg/dL • Adequate amino acids provided when there is an increase in pre-albumin of ~1 mg/dL per day

35. Parenteral Nutrition Monitoring(continued) • Acid/base balance • Adjust TPN/PPN anion concentration to maintain proper acid/base balance • Increase/decrease chloride content as needed • Since bicarbonate is unstable in TPN/PPN preparations, the precursor—acetate—is used; adjust acetate content as needed

36. Complications of Parenteral Nutrition • Hepatic steatosis • May occur within 1-2 weeks after starting PN • May be associated with fatty liver infiltration • Usually is benign, transient, and reversible in patients on short-term PN and typically resolves in 10-15 days • Limiting fat content of PN and cycling PN over 12 hours is needed to control steatosis in long-term PN patients

37. Complications of Parenteral Nutrition Support(continued) • Cholestasis • May occur 2-6 weeks after starting PN • Indicated by progressive increase in TBili and an elevated serum alkaline phosphatase • Occurs because there are no intestinal nutrients to stimulate hepatic bile flow • Trophic enteral feeding to stimulate the gallbladder can be helpful in reducing/preventing cholestasis • Gastrointestinal atrophy • Lack of enteral stimulation is associated with villus hypoplasia, colonic mucosal atrophy, decreased gastric function, impaired GI immunity, bacterial overgrowth, and bacterial translocation • Trophic enteral feeding to minimize/prevent GI atrophy

38. Parenteral Nutrition Case Study • 55-year-old male admitted with small bowel obstruction • History of complicated cholecystecomy 1 month ago. Since then patient has had poor appetite and 20-pound weight loss • Patient has been NPO for 3 days since admit • Right subclavian central line was placed and plan noted to start TPN since patient is expected to be NPO for at least 1-2 weeks

39. Parenteral Nutrition Case Study(continued) • Height: 6’0” IBW: 178# +/- 10% • Weight: 155# / 70kg 87% IBW • BMI: 21 • Usual wt: 175# 11% wt loss x 1 mo. • Estimated needs: • 2100-2450 kcal (30-35 kcal/kg) • 84-98g protein (1.2-1.4 g/kg) • 2100-2450 mL fluid (30-35 mL/kg)

40. Parenteral Nutrition Prescription • TPN via right-SC line • 2200 mL total volume x 24 hours • Amino acid: 45 g/liter= • 45g x 2.2 L= 99 grams x 4 kcals/gram =369 kcals • Dextrose 175 g/liter= • 175g x 2.2 L= 385 grams x 3.4 kcals/gram= 1309 kcals • Lipid 20% 285 mL over 24 hours • 285 mls x 2= 570 kcals • Above will provide 2275 kcal, 99g protein, • DIR=(385 g dex/ 70 kg /1440 minute in a day)*1000= 3.8mg/kg/min • LIR= (285 mls lipid * 20%)/ 70 kg=0.8 g/kg/day

41. Parenteral Nutrition Prescription • Important items to consider: • Dextrose infusion rate should be < 4 mg/kg/minute (maximum tolerated by the liver) to prevent hepatic steatosis • Lipid infusion rate should be less than 1 g/kg/day to minimize/prevent TPN-induced liver dysfunction • You may need to adjust/eliminate lipids if patient is on propofol. (1 ml propofol =1.1 kcal) • Ex. Propofol @ 10 ml/hr would provide 264 kcals (10 ml/hr x 1.1 kcal/ml, x 24 hrs) • Initiate TPN at ~½ of goal rate/concentration and gradually increase to goal over 2-3 days to optimize serum glucose control

42. Benefits of Enteral NutritionOver Parenteral Nutrition • Cost • Tube feeding cost ~ $10-20 per day • TPN costs up to $1000 or more per day! • Maintains integrity of the gut • Tube feeding preserves intestinal function; it is more physiologic • TPN may be associated with gut atrophy • Less infection • Enteral feeding—very small risk of infection and may prevent bacterial translocation across the gut wall • TPN—high risk/incidence of infection and sepsis

43. Refeeding Syndrome • “the metabolic and physiologic consequences of depletion, repletion, compartmental shifts, and interrelationships of phosphorus, potassium, and magnesium…” • Severe drop in serum electrolyte levels resulting from intracellular electrolyte movement when energy is provided after a period of starvation (usually > 7-10 days) • Physiologic and metabolic sequelae may include: • EKG changes, hypotension, arrhythmia, cardiac arrest • Weakness, paralysis • Respiratory depression • Ketoacidosis / metabolic acidosis

44. Refeeding Syndrome (continued) • Prevention and Therapy • Correct electrolyte abnormalities before starting nutrition support • Continue to monitor serum electrolytes after nutrition support begins and replete aggressively • Initiate nutrition support at low rate/concentration (~ 50% of estimated needs) and advance to goal slowly in patients who are at high risk

45. Consequences of Over-feeding • Risks associated with over-feeding: • Hyperglycemia • Hepatic dysfunction from fatty infiltration • Respiratory acidosis from increased CO2 production • Difficulty weaning from the ventilator • Risks associated with under-feeding: • Depressed ventilatory drive • Decreased respiratory muscle function • Impaired immune function • Increased infection

46. Questions • Reference: • American Society for Parenteral and Enteral Nutrition. The Science and Practice of Nutrition Support. 2001. • Han-Geurts, I.J, Jeekel,J.,Tilanus H.W, Brouwer,K.J., Randomized clinical trial of patient-controlled versus fixed regimen feeding after elective abdominal surgery. British Journal of Surgery. 2001, Dec;88(12):1578-82 • Jeffery K.M., Harkins B., Cresci, G.A., Marindale, R.G., The clear liquid diet is no longer a necessity in the routine postoperative management of surgical patients. American Journal of Surgery.1996 Mar; 62(3):167-70 • Reissman.P., Teoh, T.A., Cohen S.M., Weiss, E.G., Nogueras, J.J., Wexner, S.D. Is early oral feeding safe after elective colorectal surgery? A prospective randomized trial. Annals of Surgery.1995 July;222(1):73-7. • Ross, R. Micronutrient recommendations for wound healing. Support Line. 2004(4): 4.