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Clinical Nutrition Support Have we got it all wrong ? Dr Mike Stroud FRCP Senior Lecturer in Medicine & Nutrition, Consultant Gastroenterologist Southampton.

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Presentation on theme: "Clinical Nutrition Support Have we got it all wrong ? Dr Mike Stroud FRCP Senior Lecturer in Medicine & Nutrition, Consultant Gastroenterologist Southampton."— Presentation transcript:

1 Clinical Nutrition Support Have we got it all wrong ? Dr Mike Stroud FRCP Senior Lecturer in Medicine & Nutrition, Consultant Gastroenterologist Southampton

2 Apologies BSG talk because of NICE Guidelines NICE Guidelines 1 st Draft Contention

3 40% of hospital patients are overtly malnourished on admission, 8% severely

4 Causes of Malnourishment Conscious level Depression Anorexia Poor diet - age, poverty, junk, exercise, alcohol Dysphagia Obstruction Vomiting Pancreatic failure Liver processing Jaundice Malabsorption Increased Metabolic demands

5 Effects of Undernutrition Immunity – Increased risk of infection Hypothermia Impaired gut integrity and immunity Renal function - loss of ability to excrete Na & H2O Decreased Cardiac output Ventilation - loss of muscle & hypoxic responses Psychology – depression & apathy Anorexia ? Micronutrient deficiency Loss of strength liver fatty change, functional decline necrosis, fibrosis Impaired wound healing

6 NUTRITIONAL SUPPORT SHOULD: Improve general status Immunity Wound healing Ventilation Mobility Psychology

7 Feeding gives time for other medical and surgical interventions to work ITU patients would die at 20 to 30 days Make stronger for discharge

8 Southampton CNRD Team Meta-analyses of oral/enteral nutrition support trials. 30 RCT, n = 3258 RR 0.59 (CI 0.48 to 0.72) 10 RCT, n = 494; RR 0.29 (CI 0.18 to 0.47) Decreased complication % Decreased mortality % Controls Treatment

9 So why think we may be wrong ? Better understanding of the effects of starvation Problems in the evidence for Nutrition Support

10 UNDERNUTRITION: EFFECTS ON METABOLISM Na/K pumping: -30% Decreased AA transport Decreased protein synthesis: -40% Decreased glucose transport Decrease in metabolic mass Decreases in: GH Insulin ILGF1,2 Adrenaline NA Glucagon T4 & T3 Reduced physical activity

11 REDUCTIVE ADAPTATION Changed metabolism Reduced work, increased efficiency Metabolically stable BUT loss of reserve and functional capacity Marasmus Changed body composition Reduced Mass REDUCED FOOD INTAKE

12 MARASMUS - Metabolically stable reductive adaptation

13 Adult marasmus in anorexia nervosa Albumin 42

14 REDUCTIVE ADAPTATION DECOMPENSATION Changed body composition Reduced work, increased efficiency Marasmus Reduced Mass REDUCED FOOD INTAKE Infection, trauma, small bowel overgrowth, specific deficiency, abnormal losses, excessive intake, unbalanced intake Loss of homeostasis Kwashiorkor

15 DECOMPENSATED UNDERNUTRITION: KWASHIORKOR Variable loss of fat /muscle i.e. marasmus Response to infection, injury, fluids, feeding Massive salt and water retention +oedema Depletion of K, Mg, Ca, P Reduced intra-cellular GSH Increased urinary loss of nitrate Increased cytokines Peroxidation of cell membranes Leaky membranes Loss of vascular proteins

16 Post-surgical Metabolic decompensation Adult Kwashiorkor


18 Adult, post-surgical Oedematous malnutrition Albumin = 16

19 Recovery from oedema Albumin = 18

20 Albumin before and after the resolution of Oedema

21 The Problems of EBM in Nutrition Support –Trials use different Indications for intervention AND EXCLUSION Levels of feeding Controls Starting times Routes of support Duration of support Outcome measures

22 The Evidence Wanted – volunteers for randomized, placebo controlled trial Patients with an undoubted need for nutrition support cannot be randomized

23 Nutrition Support and Death Recommendation: –You should not let your patients go without any form of nutrition whatsoever for 3 months Grade: GPP Grade: IBO

24 Why does nutrition support help ? Jeejeebhoy KN.The benefits of nutritional support are evident when too little nutrition is given for too short a time to have any noticeable influence on lean body mass or circulating proteins

25 2. Correction of micronutrients ? Many of the detrimental effects attributed to undernourishment are more easily ascribable to micronutrient rather than macronutrient shortages.

26 Prevalence of Micronutrient Deficiencies National Dietary and Nutrition Survey (1998) Deficiency Free Living >65 yr % incidence Institution >65yr % incidence Folate29 (8 severe)35 (16 severe) Thiamine914 Vitamin B1269 Vitamin D25 Vitamin C14 (5 severe)40 (16 severe)

27 Sub-clinical deficiency Optimal level Impaired biochemical function Functional deficiency Metabolic Immunological Cognition Work capacity Clinical Deficiency Death Plasma levels may be normal

28 Metabolic evidence that Vitamin B12, Folate & Vitamin B6 occur commonly in elderly people Jorsten et al. Am J Clin Nutr 1993 Levels of homocysteine & other metabolites accumulate if B12, folate or B6 are deficient - better indicator of vitamin status SUBJECTS 99 younger healthy controls ( ) vs 64 healthy elderly ( ) vs. 286 hospital patients ( ) Elevated levels reverted to young healthy levels with vitamin supplements Healthy elderlyElderly patients low B12 6%12.5% low folate 5%19% low B6 9%51% Raised metabolites63%83%

29 Substrate A Product B Vitamin X Product C Vitamin Y Supplementation of Vitamin X can cause: Vitamin X toxicity Shortage of Substrate A Excess of product B or C Deficiency of Vitamin Y Supplementation and metabolism

30 Food First ??

31 3. Metabolic switching ? –400g carbohydrate pre-op alters insulin resistance and decreases post- operative L.O.S. by 20%* *Nygren J, Thorell A, Ljungqvist O. Preoperative oral carbohydrate nutrition: an update. Curr Opin Clin Nutr Metab Care. 2001; 4(4):

32 Issues in Nutrition Support WHEN ? WHAT ? HOW ? WHY ?

33 Starvation & Weight loss (After Allison) Catabolic Complete starvation Partial starvation Decision Box % b o d y w e i g h t Days


35 Our nearest ancestor Teleology n. the doctrine of the final causes of things: interpretation in terms of purpose (Oxford English Dictionary)

36 Teleology, anorexia and survival To ensure rest ( ? death) after injury Metabolic machinery is depleted, broken or diverted – Micronutrient & electrolyte depletion – Inadequate hepatic processing – Diet contains incorrect substrates for acute phase response Sequestration of nutrients e.g. Iron

37 Issues in Nutrition Support WHEN ? WHAT ? HOW ? WHY ?

38 PREDICTING ENERGY REQUIREMENTS Schofield/Harrison Bendict BMR + 10% - 50% Stress + Fever (10%/degree C) + 10% Thermic effect of feeding Activity -10% ventilated +10% lying in bed +20% Bed to chair +40% up around ward

39 Energy expenditure in patients Predicted REEs (Schofield BMR + 30%) vs. Deltatrak measurements of REE Measured REE - kcals/day Estimated REE - kcals/day Why are current recommendations kCals/kg /day non- protein calories ?

40 Problems of overfeeding energy Ventilatory demands - O2 and CO2 Lipid –Liver dysfunction –Immunosuppression Carbohydrate –Re-feeding syndrome –Wernicke Korsakoff –Hyper-glycaemia

41 THE REFEEDING SYNDROME K Na Mg PO4 + abnormalities of renal salt and water handling = acute circulatory failure and death ATP

42 PENG Guidelines Check K, PO4, Phos if low check Mg Correct levels Thiamine 20 kcal/kg Monitor K, PO4, Ca (Mg if supplements were given)

43 Lynne 51 1 yr 45% wt loss ?pathology, ? Eating disorder Wt 35kg, BMI 15 Na 137, K 2.5, PO4 0.54, Mg 0.8, Ca 3.3 Given 240 kcals/day via NG tube IV fluids 2 l/24 hr Thiamine, vitamin B co, K, PO4, Mg supplements

44 Lynne – contd Day 1Day 2 Creat Urea K Ca PO Mg

45 Intensive Insulin Therapy in Critically Ill Patients Van den Berghe et al. NEJM 2001; 345: PRCT in 1548 adults on surgical ICU. Insulin to maintain glucose <6.0 mmol vs. insulin to maintain glucose <12 mmol Also reduced in-hospital mortality by 34%, bloodstream infections by 46%, ARF requiring haemofiltration by 41%. P<0.04 P<0.005

46 Peritonitis (animal model) Peck et al 1989

47 Energy Requirements Initial refeeding or ongoing "stress" - cover RMR (approx 20kcal/kg) Start slowly with generous micronutrient & intracellular electrolytes Low threshold for giving insulin

48 Problems of overfeeding nitrogen ? Catabolism evolved for survival to provide AAs for immunity, inflammation and repair. AA demands are greater AND different to normal requirements. THEREFORE Diet/conventional nutritional support not only fails to meet AA needs but supply excess unwanted (toxic) AAs Why are current recommendations g N/kg with higher levels for catabolic patients ?

49 The influence of Nitrogen intake on Nitrogen Balance Severe injury/ illness

50 Current recommendations for nitrogen g N/kg with higher levels for catabolic patients Mainly based on improvements in nitrogen balance NOT outcome. Maintaining N balance with GH is harmful Studies of lower levels of feeding required

51 Peritonitis (animal model) Peck et al 1989

52 Collins et al. Am J Clin Nutr 1998 Somalia: relief camp during famine 92/ adults: 83 oedematous, 377 non-oedematous Weight 35 kg, BMI 13.1 kg/m2 Overall mortality 21% (oedematous 37%) Low protein (8.5%)High protein (16.4%) Mortality 14/5214/27 Appetitebetterpoor Oedema -7.2 g/kg/d+ 6.3 g/kg/d

53 NUTRITIONAL SUPPORT Go for Balance MACRONUTRIENTS Protein Carbohydrate Fat MICRONUTRIENTS Fat soluble - A, D, E, K Water soluble - B Group, C, etc ELECTROLYTES Na, K, Ca, Mg Phosphate ELEMENTS Iron Zn, Se, Cu, Mn


55 Issues in Nutrition Support WHEN ? WHAT ? HOW ? WHY ?

56 MEETING PATIENTS NUTRITIONAL NEEDS NORMALLY NOURISHED Undernourished BMI<20 Wt Loss >10% IF ASSESSMENT - Ward staff PROVISION - Catering MONITORING - Admission & weekly wt Partial IF ASSESSMENT - Nutrition support team PROVISION - Pharmacy PN via +/- enteral or oral ACCESS - CVP or peripheral line MONITORING - Daily reassessment including intake, fluid balance and biochemistry + weekly wt ASSESSMENT - Ward Staff & dietitians PROVISION - Catering +/- oral supplements MONITORING - Admission & weekly wt + intake records + biochemistry ASSESSMENT- Dietitians & Ward staff +/- NST PROVISION - Pharmacy enteral feeds +/- catering and sip feeds ACCESS - via NG, NJ, PEG MONITORING - At least 2 x weekly clinical reassessment + weekly wt + intake records + biochemistry

57 Parenteral nutrition

58 Total parenteral nutrition in the critically ill patient – A meta analysis. Heyland et al. JAMA 280, RCTs in 2211 surgical and ICU patients compared TPN vs standard care. NO effect on mortality NO effect on complication rate Potentially dangerous in ICU patients Why ?

59 Problems with PN studies Subject selection excludes patients requiring PN Control groups receive PN when patients develop prolonged ileus or other persisting gut dysfunction (USA Veterans PN trial 13% of controls received PN). Overfeeding (nearly all patients hyperglycaemic) PN studies therefore reflect –effects of PN performed badly in patients who dont need it.

60 PN – The 7 day myth

61 Are enteral vs. PN studies valid ? Repeated studies show benefits of enteral vs. PN feeding. BUT Enteral feeding is almost always limited in sick patients THEREFORE all studies compare different routes AND different levels of early feeding. –e.g. Meta-analyses in pancreatitis patients shows no advantage of EN vs. PN if hyperglycaemic patients left out.

62 Enteral versus parenteral nutrition: a pragmatic study. Woodcock et al. Nutrition 2001;17(1):1-12. Clinicians assessed GI function in 562 patients needing support. 231 ETF; 267 PN; 64 randomised ETF or PN –adequate nutrition in randomised patients 22% ETF vs. 75% PN (p< 0.001). –No differences in sepsis rates between groups –Feeding complications more frequent in elective and randomised ETF patients. –Higher mortality in both non-randomised and non randomised ETF groups.

63 THE SOUTHAMPTON COURSE IN PRACTICAL NUTRITIONAL SUPPORT Sep 2006 Course Directors: Brendan Moran - Consultant Surgeon Mike Stroud - Consultant Physician

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