Surgical Nutrition

1. Surgical Nutrition Dr KF Lee Division of Hepato-biliary & Pancreatic Surgery Department of Surgery Prince of Wales Hospital

2. Malnutrition • A state of nutrition in which a deficiency or excess or imbalance of energy, protein, and other nutrients cause measurable adverse effects on tissue/body form ( body shape, size & composition) and function, and clinical outcome • Macronutrients: CHO, fat, protein • Micronutrients: vitamins, trace elements present in body < 1mg / kg daily requirement < 1mg / day

3. Body mass index Weight in Kg / (height in metre)2 BMI <18.5 Severe underweight 18.5-20 Underweight 20-25 Desirable weight 25-30 Overweight >30 Obese

4. Causes of malnutrition • Inadequate food intake • Malabsorption • Inability to metabolise specific nutrients e.g. renal disease, liver disease, or inborn errors of metabolism • Increased requirement • Any one or combination of above

5. Effect of malnutrition • Weight loss • 0-10% Safe zone • 10-15% Enter danger zone consider artificial nutrition if major therapy is planned • 20-25% Danger zone nutrition support compulsory • 30-35% Risk of death due to cachexia

6. Link between malnutrition and clinical outcome • In non-obese patient, a recent loss of > 10% of the BW increase perioperative risk and impair recovery from illness • Wt loss > 20% may be life-threatening in combination with surgery • Wt loss > 30% life threatening in itself

7. Nutrition Therapy • To prevent or cure malnutrition • Provide nutrients in the most suitable form via the most suitable route and in the most appropriate quantities to meet the estimated requirements of the patient at that time • Unethical and immoral not to provide nutrition support to patients more than one week of inadequate intake

8. When to consider nutrition therapy? • When a non-obese patient has recently lost 10% of his/her BW and to continue to lose weight because of an inadequate intake • If the disease process is known to cause an inadequate intake > 10 days • The choice of nutrition therapy is important to its effectiveness

9. Nutrition Assessment Anthropometric • Body weight • Mid-arm circumference • Triceps skin fold thickness Biochemical • Albumin T1/2 20 days • Transferrin T1/2 8 days • Prealbumin T1/2 2 days • Retinol-binding protein T1/2 12 hours Immunological • Total lymphocyte count • Delayed cutaneous hypersensitivity

10. Prognostic nutritional index (PNI) • Identify nutritional indices most highly correlated with clinical relevant malnutrition • 4 indices identified: Triceps skin fold Serum albumin Serum transferrin Delayed cutaneous hypersensivity

11. Subjective global assessment (SGA) • Subjective weighting based on history and physical examination • Weight change, dietary change, GI symptoms, functional capacity, disease state and stress, physical signs of deficiency • Rating: A – well nourished B – moderately nourished C – severely malnourished

12. Choice of nutrition therapy Nutrition therapy Enteral nutrition Parenteral nutrition Oral Tube feeding Feeding stoma (NG,ND,NJ) (gastrostomy, Central Peripheral jejunostomy)

13. Enteral nutrition (EN) 5 categories: • Oral supplements: sip feeds • Standard or fibre formula • Predigested: semi-elemental or elemental • Disease specific • Specialised formula: glutamine, arginine, omega-3 fatty acid, short chain fatty acid

18. Total parenteral nutrition (TPN) • Indicated when • GIT blocked • GIT shortened (short bowel syndrome) • GIT fistulated • GIT inflammed e.g. Crohn’s diseas • GIT cannot cope e.g. severe sepsis, major burn

25. Complication of EN • GI: regurgitation, aspiration, diarrhoea, constipation, dehydration, abd discomfort (dumping syndrome), drug interaction • Tube-related: malposition, knotting of tube, accidental removal, perforation of GIT, tube obstruction, breakage, leakage, infection, bleeding, erosion, ulceration • Metabolic: electrolytes, hyper/hypoglycaemia, vitamin/trace element deficiency • Infection: aspiration, feed contamination

26. Complication of PN • Catheter related: insertion-related, thrombosis, embolism, blockage • Line sepsis • Metabolic: fluid or electrolytes abnormality, hyperosmolarity, hyper/hypoglycaemia, azotaemia, metabolic acidosis, ketosis, deranged LFT, fatty liver, vitamin/trace element deficiency

27. EN vs PN • Physiological • Safer • Fewer complication • Less monitoring • Cheaper

28. Central vs Peripheral PN • Can accommodate high osmolarity fluid; higher energy content, less volume • Less thrombophlebitis and line blockage • Usually indicated if total PN rather than supplementary PN is needed • Usually indicated if PN expected to last > 1 week • Central line related complications

29. Energy requirement • Basal energy expenditure Harris-Benedict Equations • BEE (F) = 655 + 9.6 W + 1.8 H - 4.7 A • BEE (M) = 66.5 + 13.7 W + 5 H – 6.8 A where W = body weight in Kg H = body height in cm A = age in years

30. Energy requirement • Actual energy expenditure AEE = BEE x Metabolic activity factors MAF MAF : activity factor fever factor stress factor growth factor

31. Prescribing TPN • Energy 30 Kcal /Kg/day • Water 35 ml /Kg /day • Non-protein calorie: N2 = 150 Kcal : 1 gm • Glucose: fuel for CNS, RBC, renal medulla • Proportion of lipid in providing non-nitrogen calorie: up to 30-40% • Vitamins and trace elements • Na 1 -- 1.7 mmol/ Kg /day • K 0.9 – 1.3 mmol / Kg / day

36. Monitoring • Monitor nutrition status and complication • Daily: I / O chart CBP,RFT, blood glucose Urine glucose & ketone • 2x / week BW, LFT, Ca, PO4, • Weekly Mg, Zn, lipid

38. Omega 3 fatty acid • EPA (eicosapentaenoic acid) • DHA (docosahexaenoic acid) • ALA (alpha-linolenic acid) • Fish oil • Less potent mediators for inflammation and less immunosuppression • Currently TPN lipid are mostly soybean and safflower oil, predominately omega-6 fatty acid • Recommend omega 3: omega 6 = 1:1

39. Medium chain triglyceride • MCT: 6-12 carbons, palm kernel and coconut oil • LCT: 14-24 carbons, vegetable oil (corn, safflower and sunflower) • Most TPN solution contain only LCT • MCT: rapid hydrolysis, direct venous absorption, without chylomicron formation, no need for carnitine for transport, not stored in adipose tissue, no hepatic steatosis, but ketogenic and not providing essential fatty acid

40. Arginine • Semi-essential amino acid • Metabolism leads to NO and urea • Improve cytokine and NO in patients with immunosuppression • Promote N2 retention, improve glucose tolerance, enhance wound healing and decrease risk of infection • Present in limited amount in TPN

41. Glutamine • Most abundant amino acid in body • Synthesized in greatest amount in skeletal muscle • Primary respiratory fuel for enterocyte and fibroblast in wound healing • Improve N2 balance, promote protein synthesis, enhance T-cell function • Absent in TPN solution due to instability • Stable in dipeptide form • Enteral administration better due to stimulatory effect of luminal nutrients

42. Branch chain amino acid • Leucine, isoleucine and valine • Seems to be utilized preferentially during stress, decrease catabolism and improve protein synthesis, increase nitrogen balance • Clinically useful in patients with cirrhosis and hepatic encephalopathy

43. Bring home message • Malnutrition is a common problem that is easily overlooked • Malnutrition can affect outcome of surgery significantly • Proper route and choice of nutrition therapy should be given in appropriate time • No patient should be allowed to die of starvation