5 Effects of Undernutrition Psychology –depression & apathyVentilation - loss ofmuscle & hypoxicresponsesImmunity – Increased risk of infectionliver fatty change,functional decline necrosis, fibrosisDecreased Cardiac outputRenal function - loss ofability to excreteNa & H2OImpaired woundhealingHypothermiaImpaired gutintegrity andimmunityLoss of strengthAnorexia? Micronutrient deficiency
6 NUTRITIONAL SUPPORT SHOULD: Improve general statusImmunityWound healingVentilationMobilityPsychology
7 Feeding gives time for other medical and surgical interventions to work ITU patients would die at 20 to 30 daysMake stronger for discharge
8 Southampton CNRD Team Meta-analyses of oral/enteral nutrition support trials. 10 RCT, n = 494;RR 0.29 (CI to 0.47)30 RCT, n = 3258RR 0.59 (CI 0.48 to 0.72)ControlsControlsTreatmentTreatmentDecreased complication %Decreased mortality %
9 So why think we may be wrong ? Better understanding of the effects of starvationProblems in the evidence for Nutrition Support
10 UNDERNUTRITION: EFFECTS ON METABOLISM Reduced physical activityDecrease in metabolic massDecreased proteinNa/Ksynthesis: -40%pumping: -30%DecreasedDecreasedglucose transportAA transportDecreases in:GHInsulinILGF1,2AdrenalineNAGlucagonT4 & T3
11 Metabolically stable BUT loss of reserve and functional capacity REDUCTIVE ADAPTATIONREDUCED FOOD INTAKEChanged body compositionReduced MassChanged metabolismReduced work, increased efficiencyMetabolically stable BUTloss of reserve and functional capacity‘Marasmus’
14 REDUCTIVE ADAPTATION DECOMPENSATION REDUCED FOOD INTAKEReduced work, increased efficiencyReduced MassChanged body compositionChanged body compositionMarasmusInfection, trauma, small bowel overgrowth, specific deficiency,abnormal losses, excessive intake, unbalanced intakeLoss of homeostasis‘Kwashiorkor’
15 DECOMPENSATED UNDERNUTRITION: KWASHIORKOR Response to infection, injury, fluids, feedingReduced intra-cellular GSHDepletion of K,Mg, Ca, PIncreased urinary loss of nitrateIncreased cytokinesVariable loss offat /musclePeroxidation ofcell membranesi.e. marasmusMassive salt andwater retention+oedemaLeaky membranesLoss of vascular proteins
20 Albumin before and after the resolution of Oedema
21 The Problems of EBM in Nutrition Support Trials use differentIndications for intervention AND EXCLUSIONLevels of feedingControlsStarting timesRoutes of supportDuration of supportOutcome measures
22 Wanted – volunteers for randomized, placebo controlled trial The EvidenceWanted – volunteers for randomized, placebo controlled trialPatients 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 monthsGrade: GPPGrade: 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)Free Living >65 yrInstitution >65yrDeficiency% incidence% incidenceFolate29 (8 severe)35 (16 severe)Thiamine914Vitamin B1269Vitamin D25Vitamin C14 (5 severe)40 (16 severe)
27 Sub-clinical deficiency Optimal levelImpaired biochemical functionPlasma levels may be normalFunctional deficiencyMetabolicImmunologicalCognitionWork capacityClinicalDeficiencyDeath
28 Metabolic evidence that Vitamin B12, Folate & Vitamin B6 occur commonly in elderly peopleJorsten et al. Am J Clin Nutr 1993Levels of homocysteine & other metabolites accumulate if B12, folate or B6 are deficient - better indicator of vitamin statusSUBJECTS99 younger healthy controls ( ) vs64 healthy elderly ( ) vs.286 hospital patients ( )Healthy elderlyElderly patientslow B126%12.5%low folate5%19%low B69%51%Raised metabolites63%83%Elevated levels reverted to young healthy levels with vitamin supplements
29 Supplementation and metabolism Vitamin XSubstrate AProduct BSupplementation of Vitamin X can cause:Vitamin X toxicityShortage of Substrate AExcess of product B or CDeficiency of Vitamin YVitamin YProduct C
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 WHY ?WHEN ?WHAT ?HOW ?
33 Starvation & Weight loss (After Allison)%5055606570758085909510010203040CatabolicComplete starvationPartial starvationbDecision BoxodyweightDays
34 MALNUTRITION AND THE CATABOLIC RESPONSE Pre -existing malnourishmentCatabolismMALNUTRITIONMETABOLICRATEFeeding301020NoNeed to feedSafe to Feed
35 Our nearest ancestorTeleology 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 injurySequestration of ‘nutrients’ e.g. IronMetabolic machinery is depleted, ‘broken’ or divertedMicronutrient & electrolyte depletionInadequate hepatic processingDiet contains incorrect substrates for acute phase response
37 Issues in Nutrition Support WHY ?WHEN ?WHAT ?HOW ?
38 PREDICTING ENERGY REQUIREMENTS Schofield/Harrison Bendict BMR+ 10% - 50% Stress+ Fever (10%/degree C)+ 10% Thermic effect of feedingActivity-10% ventilated+10% lying in bed+20% Bed to chair+40% up around ward
39 Energy expenditure in patients 250050010002000Predicted REEs (Schofield BMR + 30%)Estimated REE - kcals/dayvs. Deltatrak measurements of REE150050010001500200025003000Measured REE - kcals/dayWhy are current recommendations kCals/kg /day non-protein calories ?
40 Problems of overfeeding energy Ventilatory demands - O2 and CO2LipidLiver dysfunctionImmunosuppressionCarbohydrateRe-feeding syndromeWernicke KorsakoffHyper-glycaemia
41 THE REFEEDING SYNDROME Mg+ abnormalities of renal saltand water handlingK= acute circulatoryfailure and deathNaPO4ATP
42 PENG Guidelines Check K, PO4, Phos if low check Mg Correct levels Thiamine20 kcal/kgMonitor K, PO4, Ca (Mg if supplements were given)
43 Lynne 51 1 yr 45% wt loss ?pathology, ? Eating disorder Wt 35kg, BMI 15Na 137, K 2.5, PO4 0.54, Mg 0.8, Ca 3.3Given 240 kcals/day via NG tubeIV fluids 2 l/24 hrThiamine, vitamin B co, K, PO4, Mg supplements
44 Lynne – cont’d Day 1 Day 2 Creat 166 110 Urea 15.5 11.4 K 2.5 3.4 CaPOMg
45 Intensive Insulin Therapy in Critically Ill Patients Van den Berghe et al. NEJM 2001; 345:1359-1367. PRCT in 1548 adults on surgical ICU. Insulin to maintain glucose <6.0 mmol vs. insulin to maintain glucose <12 mmolAlso reduced in-hospital mortality by 34%, bloodstream infections by 46%, ARF requiring haemofiltration by 41%.P<0.005P<0.04
47 Energy Requirements Initial refeeding or ongoing "stress" - cover RMR (approx 20kcal/kg)Start slowly with generous micronutrient& intracellular electrolytesLow 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.THEREFOREDiet/conventional nutritional support not only fails to meet AA needs but supply excess unwanted (toxic) AAsWhy 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 0. 2 - 0 Current recommendations for nitrogen g N/kg with higher levels for catabolic patientsMainly based on improvements in nitrogen balance NOT outcome.Maintaining N balance with GH is harmfulStudies of lower levels of feeding required
52 Collins et al. Am J Clin Nutr 1998 Somalia: relief camp during famine 92/93573 adults: 83 oedematous, 377 non-oedematousWeight 35 kg, BMI 13.1 kg/m2Overall mortality 21% (oedematous 37%)Low protein (8.5%) High protein (16.4%)Mortality 14/ /27Appetite better poorOedema g/kg/d g/kg/d
53 NUTRITIONAL SUPPORT Go for Balance MACRONUTRIENTSProteinCarbohydrateFatMICRONUTRIENTSFat soluble - A, D, E, KWater soluble - B Group, C, etcELECTROLYTESNa, K, Ca, MgPhosphateELEMENTSIronZn, Se, Cu, Mn
58 Total parenteral nutrition in the critically ill patient – A meta analysis. Heyland et al. JAMA 280, 199826 RCTs in 2211 surgical and ICU patients compared TPN vs standard care.NO effect on mortalityNO effect on complication ratePotentially dangerous in ICU patientsWhy ?
59 Problems with PN studies Subject selection excludes patients requiring PNControl 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 reflecteffects of PN performed badly in patients who don’t need it.
61 Are enteral vs. PN studies valid ? Repeated studies show benefits of enteral vs. PN feeding.BUTEnteral feeding is almost always limited in sick patientsTHEREFOREall 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 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; PN; randomised ETF or PNadequate nutrition in randomised patients 22% ETF vs. 75% PN (p< 0.001).No differences in sepsis rates between groupsFeeding 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 2006Course Directors:Brendan Moran - Consultant SurgeonMike Stroud - Consultant Physician