1. Nutrition in surgery Alexander Sunde

2. Overview  Nutrients and energy  Definition of malnutrition  Causes of malnutrition  Effects of malnutrition  Effects of stress during starvation  Complications of malnutrition  Approach to the patient  Enteral and parentereal feeding

3. Nutrients  Can be divided into Macro – and Micronutrients 1.Energy giving nutrients (Carbohydrates, fats, and protein) 2.Vitamins 3.Minerals 4.Water Carbohydrates: Fast source of energy used for CNS function Fats: Major energy source, stored in the organism Protein: Building blocks needed to balance metabolism

4. Energy expenditure  Calories we get into our body are provided mainly by carbohydrates and fat. 1.Fat = 9kcal/g 2.Carbohydrate = 4 kcal/g 3. Protein = 4 kcal/g  REE/BMR: is a part of the daily requirement, needed for organs, synthesis and electrochemical gradients of cells. It is 22kcal/kg/day on average, and is measurable using calorimetry or the harris – benedict equation.  Daily caloric requirements : 30-35kcal/kg or on average for women 1800kcal/day and 2800kcal/day for males, with variations depending on activity, pregnancy and weight.  Metabolic stress, eg. Sepsis, trauma, surgery etc. Increases the daily demand about 35-40kcal/kg/day

5. Malnutrition  Normal physiology of the human body is depending on a balance between nutritional intake and metabolism.  Any imbalance will manifest as nutritional deficiencies or excess.

6. Malnutrition  Nutrition is the process of providing or obtaining the energy necessary for adequate health and growth.  Nutrients are non-synthesized substances the body depend on getting from the diet.  Malnutrition (def. ESPEN guidelines) ”A condition that develops when the body does not get the right amount of vitamins, minerals and other nutrients it needs to maintain healthy tissues and organ function”  Undernutrition and overnutrition/obesity are both equally malnournourished states of the body.

7. Types of undernutrition

8. Protein Energy Malnutrition (PEM), types:  PEM is potentially fatal, and the leading cause of death in developing countries  PEM occurs in one of two surgical patient and in 48% of all other hospitalized patients. 1.Kwashiorkor, aka wet PEM, is characterized primarily by protein deficiency. It causes ascites, hepatomegaly, edema, dry skin and hair discoloration. Some symptoms are anemia, diarrhea, and fluid / electrolyte disturbances. The immunesystem is often weakened aswell. 2.Marasmus is primarily caused by energy deficiency, characterized by stunted growth and muscle/tissue wasting. Weakness accompanies marasmus, patient will have a skeletal appearance as all body fat and muscles are wasted. Other symproms are hypothermia, bradycardia / bradypnea, mental retardation/ behavioral retardation diarrhea, dry and ”baggy” skin, and sparse hair. 3.Kwashiorkor-like, secondary PEM can develop in patients who suffer trauma or other life-threatening illness like sepsis or burns, and the onset is often so sudden that body fat and muscle mass may not change. 4.Absence of edema distinguish marasmus-like secondary PEM, a gradual wasting process that begins with weight loss and progresses to mild, moderate or sever malnutrition. It is usually associated with cancer, COPD, or any other chronic disease that is inactive, or progressing slowly. 5.It is possible to have kwashiorkor and marasmus at the same time, most often in patients with a chronic, inactive condition develops symptoms of an acute illness.

9. Simplification

10. Summary of differences:

11. Some major causes of malnutrition

12. Reduced food intake – simple starvation  Physiologically the body will react and adapt biochemically, using specific pathways and mechanisms in response to simple starvation:  Increased glycogenolysis, lipolysis, reduced insulin and increased glucagon and secretion of catecholamines during the period of <72hrs. This is then Followed by gluconeogenesis using aa`s from muscle and glycerol from stored fat after depleting of glycogen stores, also within this 72hr period of Short Uncomplicated Fasting/Starvation.  Beyond this: Reduced BMR 10-15%, further decrease pfp insulin, redused energy expenditure, increase B-oxidation of fatty acids, increased ketogenesis, the brain adapts to the use of ketones as fuel and net tissue catabolism reduces. Period of Prolonged starvation.

13. Altered metabolism – Stress starvation  As mentioned on a previous slide, certain stressful states of the organism will influence the balance in metabolism drastically, such as eg. Surgery, burns, necrosis, radiation, or different types of traumatic injuries etc.  The response to this type of starvation differs in many ways from the simple type, mainly due to the increased neuroendocrine stress response and the effect of cytokines, TNFs, interleukins which causes rapid loss of tissues.

14. Stress response

15. Differences in resting metabolism

16. Other key differences:

17. Why important in surgery?  Between 30 – 50% of all hospitalized patients are malnourished, and the effects of this in surgical patients are well discribed in litterature but often overlooked in a clinical setting.  Surgical procedures (and subsequent fasting) after admisson can cause this pat. group to enter a state of severe malnutrition very fast, even before the treating team realizes it.  A patient with severe protein depletion is evident to be at a much greater risk of post-operative complications such as eg. Pneumonia, SSI (Surgical site infections), and impaired wound healing etc. thus, prolonging the hospital stay  Even in patients without obvious malnutrion, perioperative nutritional support is indicated when oral food intake is not feasible or inadequate for a longer period of time. (ERAS programs studies: http://www.ncbi.nlm.nih.gov/pubmed/24718444)

18. Other examples of complications

19. What to look for in patients?  According to the ESPEN* guidelines: Undernutrition: 1.BMI < 18kg/m2 2.Weight loss > 10-15% last 6 months 3.Serum albumin <30g/L w/o Renal/hepatic dysfunction 4.<80% of ideal body weight Overnutrition: 1.BMI > 30kg/m2 2.Bodyweight > 20% of ideal weight *(European Society for Clinical Nutrition and Metabolism)

20. How to assess nutritional status?  History  Physical exam  Laboratory investigation  Nutritional assessment score

21. History taking  Presenting complaints – Vomiting, dysphagia, diarrhea etc.  Comorbidities – Obesity, Malignancy, IBD, COPD etc.  Social and dietary history – Socioeconomy, food habits, (ask about intake, type, amount etc) alcohol or drug abuse etc.  Mental status – Anorexia, depression etc. Ask about loss of weight the last 6 months.

22. Physical examination  Antrhopometry: -Measure weight, height, bmi, skinfold thickness of bi-triceps and mid- arm circumference.  Some less obvious signs of malnutrition: Hair: easy pluckability Face: Nasolabial seborrhoea, angular fissures of lip Muscle bulk/waste: Temporalis, thenareminece, lumbricals Skin: increased folding, hyperkeratosis, non healing ulcer Limbs: dependant edema  Also assess general condition and appearence, and muscle strength eg. during handshake

23. Physical examination NB: Anthropometry cannot identify Specific nutrient deficiency, only assess subcutaneous lipid stores.

24. Laboratory tests  This is to detect subclinical deficiencies in patients Nitrogen balance – index of protein gain or loss Serum albumin – sensitive, non-specific index of malnutrition (< 35g/L). Level falls due to increased extravascular volume or TNF mediated inhibition of albumin synthesis. Creatinine excretion – amount produced is proportional to skeletal muscle mass Also a FBC is usually assessed, eg. to exclude anemia

25. Summary of nutritional assessment

26. Assessment of nutritional requirements  As mentioned total daily energy requirement vary and depend on weight, sex and activity. But also on clinical status.  During assessment bear in mind the possibility of refeeding syndrome; refeeding the chronically starved may cause hypokalemia and hypophosphatemia.  Estimate the total energy expenditure and add the respective factors for activity, injury and diet. Generally aprox. 40kcal/kg/day for the average surgical patient in need for nutritional support.

27. Estimating energy needs in surgical patients Diet induced thermogenesis: Factor 1.15 added to calculation if patient is being fed

29. Clinical nutrition  Fluids or formulae given intravenously or orally respectively. These contain everything the patient needs in terms of energy, protein, electrolytes, minerals and vitamins.

30. Indications

31. Enteral or parenteral

32. Enteral feeding  Indications: 1.Malnourished patient expected to be unable to eat adequately for more than 5 days 2.Nourished patient expected to be unable to eat more than 7 days 3.Adaptive short bowel syndrome phase 4.Post-severe trauma or burn injury  Contraindications: Mechanical ileus, non stabile severe shock, or bowel ischemia. Mixed enteral / parenteral is an option in some cases.

33. Enteral feeding

34. Enteric solution of nutrients  After calculating the energy needs of the individual patient, a solution is made of: Synthetic aminoacids Fat Dextrose Na+, K+, Ca++, Mg++ Trace elements and vitamins  All sources of the macronutrients are derived from a careful choice of base materials, to ensure the completeness- rule is achieved, and the safety of intolerant or allergic patients. The formulae is free of Lactose, Cholesterol, Purines and Gluten

36. Complications  Aspiration Precautions to prevent aspiration: patient at 30 degree angle, conscious if possible, stop feeding at 11 pm. Use french 10 tube and clean it properly.  Perforation (rare)  Malposition of catheter  Nausea and vomiting  Malabsorption (hyperosmolarity) -Steatorrhea/diarrhea -Dehydration Hyperosmolarity is better tolerated by stomach: Gastric feeding gradually increase osmolality, and then the volume. In the small bowel the opposite.

37. Monitoring gastric residuals  Assess GI tolerance to EN by monitoring abd. discomfort, nausea and vomiting, abd. distension, and abnormal bowel sounds or stool patterns.  Gastric residual volumes are used to evaluate gastric emptying, and if greater than 200-250mL should raise concerns about intolerance and potential risk of regurgitation and aspiration.  If associated with signs/symptoms of intolerance, feeding should be stopped.  If abdominal exam is normal, but still residue of 200-250mL, feeding is postponed and residue rechecked minimum 1 hr. after. If high residual persist asymptomatically a promotility agent may be added to the feeding regimen.

38. Parenteral feeding  Patient receives feeding intravenously either via a central vein or peripheral vein.

39. Indications  Severe gastrointestinal cases, in need of feeding Intraabdominal sepsis Severe trauma Blocked GI tract (outlet obstr. etc.) Short bowel syndrome Fistulae eg. Proximal entercutaneous IBD

40. Solution  AIO bags or ”All in one” bags, contains Glucose, Aminoacids Triglycerids, Electrolytes, Trace elements and vitamins.  Individual solutions can also be given as indicated, proteins, lipids, glucose, and vitamins. Patient is readily monitored and if needed the infusion of respective nutrient can be stopped, eg. If hypertriglyceridemia, lipid infusion is stopped.  Electrolytes can be limited in the AIO bags, but is usually administered separately if needed.  Depend on the site of catheterization, a central vein tolerates a higher osmolarity 1300-1800mOsm/L, in contrast to the peripheral access with a maximum of 900mOsm/L.  Due to this PPN needs to be given at higher volumes than the central line to maintain same effect.

41. Complications  Hepatic steatosis (within 1-2 weeks) Usually benign, transient and reversible in patients on short term PN  Cholestasis (within 2-6 weeks)  Gastrointestinal atrophy  And also of course complications related to the catheter itself, the risk of infection and sepsis are very high compared to enteral feeding. Other early complications ass. with insertion are pneumothorax, arterial laceration, hemothorax, mediastinal hematoma, brachial nplexus injury, air embolus or hydrothorax.  Late comlications of insertion are thrombosis with upper arm swelling or septic thrombosis, or erosion of the catheter to the bronchus or RA.

43. Summary of enteral/parenteral feeding  Advantages of enteral feeding (if possible): 1.More physiological, the liver is not bypassed 2.Lesser cardiac work 3.Safer and more efficient 4.Better tolerated 5.More economical

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