Clinical Nutrition Support Have we got it all wrong ? Dr Mike Stroud FRCP Senior Lecturer in Medicine & Nutrition, Consultant Gastroenterologist Southampton
Mar 28, 2015
Clinical Nutrition Support Have we got it all wrong ?
Dr Mike Stroud FRCPSenior Lecturer in Medicine & Nutrition,
Consultant GastroenterologistSouthampton
Apologies
• BSG talk because of NICE Guidelines
• NICE Guidelines 1st Draft
• Contention
40% of hospital patients are overtly malnourished on admission, 8% severely
Causes of Malnourishment
Conscious levelDepressionAnorexia
Poor diet - age, poverty, junk, exercise, alcohol
Dysphagia
ObstructionVomiting
Pancreatic failureLiver processing
Jaundice
Malabsorption
Increased Metabolic demands
Effects of Undernutrition
Immunity – Increased risk of infection
HypothermiaImpaired gutintegrity andimmunity
Renal function - loss of ability to excrete Na & H2O
Decreased Cardiac output
Ventilation - loss ofmuscle & hypoxic responses
Psychology –depression & apathy
Anorexia ? Micronutrient deficiency
Loss of strength
liver fatty change, functional declinenecrosis, fibrosis
Impaired wound healing
NUTRITIONAL SUPPORT SHOULD:
Improve general status Immunity Wound healing Ventilation MobilityPsychology
Feeding gives time for other medical and surgical interventions to work
ITU patients would die at 20 to 30 days
Make stronger for discharge
Southampton CNRD Team Meta-analyses of oral/enteral
nutrition support trials.
0 10 20 30 40 50 0 5 10 15 20 25 30
30 RCT, n = 3258RR 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 Controls
Treatment Treatment
So why think we may be wrong ?
• Better understanding of the effects of starvation
• Problems in the evidence for Nutrition Support
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
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
MARASMUS - Metabolically stable reductive adaptation
Adult marasmus in anorexia nervosa
Albumin 42
REDUCTIVE ADAPTATIONDECOMPENSATION
Changed body composition 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’
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
Post-surgicalMetabolic decompensationAdult ‘Kwashiorkor’
Adult, post-surgicalOedematous malnutrition
Albumin = 16
Recovery from oedema Albumin = 18
Albumin before and after the resolution of Oedema
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
The Evidence
Wanted – volunteers for randomized, placebo controlled trial
Patients with an undoubted need for nutrition support cannot be randomized
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
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
2. Correction of micronutrients ? Many of the detrimental effects attributed to
undernourishment are more easily ascribable to micronutrient rather than macronutrient shortages.
Prevalence of Micronutrient DeficienciesNational Dietary and Nutrition Survey (1998)
DeficiencyFree Living >65 yr
% incidenceInstitution >65yr
% incidence
Folate 29 (8 severe) 35 (16 severe)
Thiamine 9 14
Vitamin B12 6 9
Vitamin D 2 5
Vitamin C 14 (5 severe) 40 (16 severe)
Sub-clinical deficiencyOptimal level
Impaired biochemical function
Functional deficiency Metabolic Immunological Cognition Work capacity
ClinicalDeficiency
Death
Plasma levels may be normal
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 (19 - 55) vs 64 healthy elderly (65 - 88) vs. 286 hospital patients (61 - 97)
Elevated levels reverted to young healthy levels with vitamin supplements
Healthy elderly Elderly patients
low B12 6% 12.5%
low folate 5% 19%
low B6 9% 51%
Raised metabolites 63% 83%
Substrate A
Product B
Vitamin X
Product C
Vitamin YSupplementation of Vitamin X can cause:Vitamin X toxicityShortage of Substrate AExcess of product B or CDeficiency of Vitamin Y
Supplementation and metabolism
Food First ??
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):255-259
Issues in Nutrition Support
WHEN ?
WHAT ?
HOW ?
WHY ?
Starvation & Weight loss(After Allison)
50
55
6065
70
75
80
8590
95
100
0 10 20 30 40 50 60 70
Catabolic
Complete starvation
Partial starvation
Decision Box%bodyweight
Days
MALNUTRITION AND THE CATABOLIC RESPONSE
METABOLIC
RATE
MALNUTRITION
Pre -existing malnourishment
Catabolism
Feeding
10 2030
Safe to FeedNeed to feedNo
Our nearest ancestor
Teleology n. the doctrine of the final causes of things: interpretation in terms of purpose (Oxford English Dictionary)
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
Issues in Nutrition Support
WHEN ?
WHAT ?
HOW ?
WHY ?
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
Energy expenditure in patients
Predicted REEs (Schofield BMR + 30%)vs. Deltatrak measurements of REE
Measured REE - kcals/day
0
500
1000
1500
2000
2500
0 500 1000 1500 2000 2500 3000
Est
imat
ed R
EE
- k
cals
/day
Why are current recommendations 35 - 40 kCals/kg /day non-protein calories ?
Problems of overfeeding energy• Ventilatory demands - O2 and CO2
• Lipid – Liver dysfunction– Immunosuppression
• Carbohydrate– Re-feeding syndrome– Wernicke Korsakoff
– Hyper-glycaemia
THE REFEEDING SYNDROME
K
Na
Mg
PO4
+ abnormalities of renal salt and water handling
= acute circulatory failure and death
ATP
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)
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 tubeIV fluids 2 l/24 hrThiamine, vitamin B co, K, PO4, Mg supplements
Lynne – cont’d
• Day 1 Day 2• Creat 166 110• Urea 15.5 11.4• K 2.5 3.4• Ca 3.0 2.37
PO4 0.54 0.17Mg 0.8 0.4
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 mmol
• Also reduced in-hospital mortality by 34%, bloodstream infections by 46%, ARF requiring haemofiltration by 41%.
0
5
10
15
20
25
ICU mortality ICU >5 daymortality
InsulinConventional
P<0.04
P<0.005
Peritonitis (animal model)
0
10
20
30
40
50
60
Survival @ 17 days
100kcal/kg/day125kcal/kg/day150kcal/kg/day175/kcal/kg/day
Peck et al 1989
Energy RequirementsInitial refeeding or ongoing "stress" - cover RMR (approx 20kcal/kg)Start slowly with generous micronutrient & intracellular electrolytes
Low threshold for giving insulin
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 0.2 - 0.3g N/kg with higher levels for catabolic patients ?
The influence of Nitrogen intake on Nitrogen Balance
Severe injury/illness
• Current recommendations for nitrogen 0.2 - 0.3g 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
Peritonitis (animal model)
0
5
10
15
20
25
30
35
40
45
Survival @ 14 days
5% protein10% protein15% protein20% protein
Peck et al 1989
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/m2
Overall mortality 21% (oedematous 37%)
Low protein (8.5%) High protein (16.4%)
Mortality 14/52 14/27
Appetite better poor
Oedema -7.2 g/kg/d + 6.3 g/kg/d
NUTRITIONAL SUPPORT Go for Balance
MACRONUTRIENTSProteinCarbohydrate Fat
MICRONUTRIENTSFat soluble - A, D, E, KWater soluble - B Group, C, etc
ELECTROLYTESNa, K, Ca, MgPhosphate
ELEMENTSIron
Zn, Se, Cu, Mn
NUTRITIONAL SUPPORT
MAINTAINREPAIR REPLETE
Issues in Nutrition Support
WHEN ?
WHAT ?
HOW ?
WHY ?
MEETING PATIENTS NUTRITIONAL NEEDS
NORMALLY NOURISHEDUndernourished
BMI<20Wt 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
Parenteral nutrition
Total parenteral nutrition in the critically ill patient – A meta analysis.
Heyland et al. JAMA 280, 1998
• 26 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 ?
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 don’t need it.
PN – The 7 day myth
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.
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.
THE SOUTHAMPTON COURSE IN PRACTICAL
NUTRITIONAL SUPPORT
Sep 2006
Course Directors: Brendan Moran - Consultant SurgeonMike Stroud - Consultant Physician