1. Kelvin Chan Department of Surgery, Queen Elizabeth Hospital Joint Hospital Surgical Grand Round 2013 nutrition in surgery facts, myths and controversies

2. Nutrition in surgery Malnutrition afflicts 30-55% hospitalised patients Surgical illness and malnutrition –Intestinal dysfunction (intestinal obstruction, ileus) –Cancer cachexia Malnutrition and adverse surgical outcomes –Delayed wound healing –Increased morbidity and mortality –Increased length of stay & cost of care August. JPEN 2002. Shopbell. The Science and Practice of Nutrition Support. 2001.

3. Metabolic response to injury Backburn. Surg Clin N Am 2011. INJURY EBB PHASE 24-48 hours CATABOLIC FLOW PHASE 7 days + ANABOLIC FLOW PHASE  oxygen consumption  body temperature  Energy expenditure Road to recovery Neurohormonal control Catecholamines Glucagon, cortisol Cytokines TNF- , IL-1, IL-6  oxygen consumption Insulin resistance Protein catabolism

4. Backburn. Surg Clin N Am 2011.

5. Goals of nutritional support Preserve lean body mass Maintain immune function Avert metabolic complications Martindale. Crit Care Med 2009.

6. Nutritional assessment History –Medical illness –Oral intake –Marked weight loss Physical examination –Oedema, ascites, cachexia, muscle wasting &c –Anthropometric measurements Biochemical profile –Albumin, prealbumin, transferrin –Lymphocyte count August. JPEN 2002. Backburn. Surg Clin N Am 2011.

7. ENERGY 20-35 kcal / kg / day Nutritional requirement Carbohydrates 4 kcal/g Lipids 9 kcal/g Amino acids 4 kcal/g Essential amino acids August. JPEN 2002. Fluid & Electrolytes Trace elements Vitamins

8. Nutritional requirement Harris Benedict Equation BEE = 66.5 + (13.7 x weight in kg) + (5 x height in cm) – (6.8 x age) BEE = 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age) REE = BEE x activity factor x injury factor Over 200 other formulae for estimation of caloric requirement.

9. Indirect calorimetry Gold standard Estimation of caloric requirement by measuring CO2 production and oxygen consumption May be useful in critically ill patients with severe trauma, burns, pancreatitis Routine use not recommended

10. Modes of nutritional support Standard nutritionParenteral nutritionEnteral nutrition

11. Modes –Gastric tube –Post-pyloric tube –Gastrostomy –Jejunostomy Contraindications –Intestinal obstruction –Paralytic ileus –Intractable vomiting / diarrhoea –High output fistulae –Gastrointestinal ischaemia –Diffuse peritonitis –Fulminant sepsis Fukatsu. Surg Clin N Am 2011.

12. Enteral nutrition Benefits of enteral nutrition –Stimulate mucosal blood flow –Stimulate T and B cells within Peyer patches –Improve secretory IgA production –Maintain integrity of mucosal barrier & villous height –Reduce bacterial translocation Reduce mortality, length of stay, infectious complications in trauma & burns patients Martindale. Crit Care Med 2009. August. JPEN 2002. Fukatsu. Surg Clin N Am 2011.

13. Buchman, JPEN 1995 Healthy subjects After 14 days of TPN

14. Enteral nutrition Enteral feeding should be started early within the first 24–48 hours following admission The feedings should be advanced toward goal over the next 48–72 hours Problems –Risk of aspiration –Inadequate caloric delivery, especially feeding has to be withheld with large gastric residual volumes Martindale. Crit Care Med 2009. August. JPEN 2002.

15. Parenteral nutrition Indicated for those requiring nutritional support but –Contraindication to enteral nutrition –Inadequate caloric intake despite enteral nutritional support Should be initiated if –Inadequate oral intake for 7-14 days / expected over 7-14 days –Malnourished patients 5-7 days pre-operatively and continued to post- operative period Parenteral nutrition of less than 5–7 days have no outcome effect and may result in increased risk to the patient Martindale. Crit Care Med 2009. August. JPEN 2002.

16. Parenteral nutrition Risks of parenteral nutrition –Sepsis & catheter related complications –Fluid & electrolyte imbalance –Hyperglycaemia –Hepatic steatosis, cholestasis –Liver failure

17. 1. Carbohydrate (glucose) 2. Lipid emulsion 3. Amino acids 4. Electrolytes CENTRAL PREPARATION Osmolarity 1500 mosmol/L Nitrogen 12 grams Non protein calorie 1300 kcal PERIPHERAL PREPARATION Osmolarity 750 mosmol/L Nitrogen 5.4 grams Non protein calorie 900 kcal [SmofKabiven 1470mL & Kabiven Peripheral 1440mL. Fresenius Kabi AG, Germany]

18. Immune-modulating nutrition

19. Nutrition has major effects on the immune system Mechanisms not completely understood Favourable outcomes in selected surgical patients –Head and neck cancers –Upper gastrointestinal cancer –Severe trauma –Severe burns (>30% TBSA) –Surgical ICU patients Key nutrients: arginine, glutamine, omega-3 fatty acids and antioxidants Martindale. Crit Care Med 2009.

20. Immune-modulating nutrition Omega-3 fatty acids –Omega-3 : Fish oils –Omega-6 : vegetable oils –Essential polyunsaturated fatty acids –Omega-3 fatty acids displace omega-6 from the cell membranes of immune cells, reduces systemic inflammation through the production of biologically less active prostaglandins & leukotrienes –Reduce ARDS and the likelihood of sepsis Jayarajan. Surg Clin N Am 2011. Martindale. Crit Care Med 2009.

21. Immune-modulating nutrition Glutamine –Conditionally essential amino acid –Functions Fuel source for enterocytes & immune cells Cellular respiration T-cell proliferation B-cell differentiation Production of IL-2 –Parenteral glutamine reduces infectious complications, length of stay –No impact on mortality –No effect from enteral supplement Jayarajan. Surg Clin N Am 2011. Vanek. Nutr Clin Pract 2011.

22. Immune-modulating nutrition Arginine –Conditionally essential –Functions Secretion of insulin & growth hormones Protein synthesis (Nitric oxide) vasodilation, regulate immune cells (Polyamines) regulate pro-inflammatory cytokines & T-cell –Increased mortality in severely septic patients (44% vs 14%, p = 0.039) –? Increased NO in septic / haemodynamically unstable patients Jayarajan. Surg Clin N Am 2011. Morris. Am J Clin Nutr 2006. Martindale. Crit Care Med 2009.

23.  infection  ventilator days  length of stay No change in mortality Martindale. Crit Care Med 2009.

24. Immune-modulating nutrition Limitations –Mechanisms not completely understood –Few studies have addressed the individual nutrients, their specific effect, or their proper dosing –Laboratory findings difficult to study in clinical setting –Interpretation of results limited by heterogeneity of clinical studies –Large scale clinical trials needed Martindale. Crit Care Med 2009. Jayarajan. Surg Clin N Am 2011.

25. Conclusions Nutritional support forms an integral part of comprehensive surgical care Nutritional assessment should be performed for high risk patients Appropriate nutritional support potentially improves surgical outcomes Enteral feeding should be started early whenever the GI tract is functional and the clinical condition permits Emerging evidence has shown that immune-modulating nutrition may improve surgical outcomes. Benefits have not been consistently demonstrated in all surgical patients. Further research is required to clarify the type of immune-modulating nutrient, the dosage and target patients that would benefit.

26. Thank you