- 1. NUTRITION and IMMUNONUTRITION in the ICU Marcia McDougall
October 2007
2. A slender and restricted diet is always dangerous in chronic
and in acute diseases Hippocrates 400 B.C. 3. 4. Critical
Illness
- Extreme physiological stress/organ failure
- Acute phase response: TNF, IL-6, IL-1
- Immuno-suppression: monocytes, M , NK cells, T and B
lymphocytes
- Insulin resistance: hyperglycaemia
- Protein loss and fat gain in muscle
5. Consequences of malnutrition
- Increased morbidity and mortality
- Impaired tissue function and wound healing
- Defective muscle function, reduced respiratory and cardiac
function
- Immuno-suppression, increased risk of infection
- CIPs lose around 2%/day muscle protein
6. Scale of the problem
- McWhirter and Pennington 1994:
- >40% of hospital patients malnourished on admission
- Estimated cost to hospitals: 3.8bn/yr
- Many ICU patients malnourished or at risk on ICU admission
7. ICU Nutrition in the 1970s 8. ICU Nutrition through the ages
Overfeeding 1980s 9.
- 1970s: TPN - separate CH, AAs and Lipids
- 2500-3000kcals/day: Lactic acidosis, high glucose loads, fatty
livers, high insulin reqt
- Single lumen C/Lines, no pumps
- Urinary urea measured, N calculated
- 1980s: Scientific studies of metabolism: recognition of
overfeeding
- 1990s: nitrogen limitation: 0.2g/kg/24hr, start of
immunonutrition trials
- 2000s: glucose control, specific nutrients
10. Nutrition trials in ICU
- Heterogeneous and complex patients
- Different feeding regimens
- Underfeeding failure to deliver nutrients
- Overfeeding adverse metabolic effects
- Scientific basis essential
11. What is the evidence in ICU?
- Early enteral feeding is best
- Hyperglycaemia/overfeeding are bad
- PN meta-analyses controversial
- Nutritional deficit a/w worse outcome
- EN a/w aspiration and VAP, PN infection
- EN and PN can be used to achieve goals
- Protocols improve delivery of feed
- Some nutrients show promising results
12. Unanswered questions
- Should we aim for full calorific delivery ASAP using EN +
PN?
- What are the best lipids to use in PN?
- What is the role of small bowel feeding?
- Which patients will benefit from immuno-nutrition?
- The future: targeted Nutrition Therapy?
13. Current practice - Scotland
- SICS Nutrition Survey 2005-2006
- Wide variation in PN and NJ feeding use
- Wide variation in opinions about nutrition
- Lack of education about nutrition
- Lack of interest from clinicians
- Nutrition teams in 11/24 hospitals (QIS)
- Discussion between dietitians and doctors limited
14. % patients receiving PN/year 15. NJ feed: patient use per
year 16. What is the maximum amount of time an ICU patient should
go without nutrition? 17. Nutrition QI Study
- Canadian Critical Care Network
- 156 units cf CCCN guidelines
- Protocols/Glycaemic control/Bed elevation
18. 19. Guidelines 20. systematically developed statements to
assist practitioner and patient decisions about appropriate health
care for specific clinical circumstancesU.S. Institute of Medicine
EBM - the conscientious, explicit, and judicious use of current
best evidence in making decisions about the care of individual
patientsSackett DL et al. BMJ 1996 21. What Guidelines are
available?
- Canadian Critical Care Network 2003/2007: Clinical Practice
Guidelines
- ICS: Practical Management of Parenteral Nutrition in Critically
Ill Patients 2005
- ESPEN: Enteral Nutrition 2006
- NICE: Nutrition Support in Adults 2006
22. Organisation of Nutrition Support 3. NICE Guidelines for
Nutrition Support in Adults 2006 Screen Recognise Treat Oral
Enteral Parenteral Monitor & Review 23. Screen
- Various nutritional screening tools
- Malnutrition Universal Screening Tool from the Malnutrition
Advisory Group of BAPEN
- Low risk: routine clinical care,
- High risk: treat- refer to dietitian/local protocols
24. Screening in ICU
- MUST not very helpful in guiding decisions
- Almost all patients require artificial nutrition- cannot
observe
- What about refeeding syndrome?
- Needs adaptation using NICE Guidelines
- Adapted MUST for ICU: Uses BMI/weight loss/food intake +
refeeding risk assessment; linked to feeding flowchart
25. Step 3 Treat: Enteral use the most appropriate route of
access and mode of delivery has a functional and accessible
gastrointestinal tract if patient malnourished/at risk of
malnutrition despite the use of oral interventions and 3. NICE
Guidelines for Nutrition Support in Adults 2006 26. Step 3 Treat:
PN and has either introduce progressively andmonitor closely if
patient malnourished/at risk of malnutrition a
non-functional,inaccessible or perforated gastrointestinal tract
inadequate or unsafe oralor enteral nutritional intake use the most
appropriate route of access and mode of delivery3. NICE Guidelines
for Nutrition Support in Adults 2006 27. Routes Of feeding 28.
REDUCED ENTERAL STIMULATION
- Peyers patch leukotrienes + MAdCAM-1
- T & B cells in Peyers patches, Lamina propria &
epithelium
- Reduced secretory IgA and altered cytokines
29. Enteral
- Preserves intestinal mucosal structure and function
- Reduced risk of infectious complications cf PN (?)
30. NG problems
- Risk of microaspiration in ICU
- High gastric aspirates with opioids, sepsis, electrolyte
imbalances
- PEG/gastrostomy feeding for long-term >4 weeks
31. Jejunal Feeding
- Surgical jejunostomy: at laparotomy
- May reduce incidence of aspiration
- Sometimes increases dose of EN given over NG
32. Parenteral Nutrition
- GI tract cannot be accessed
- Inadequate enteral nutrition 10)
- Hx alcohol abuse or drugs including insulin, chemotherapy,
antacids or diuretics
- (Critically low levels of PO 4 2- , K +and Mg 2+)
40. Managing refeeding problems
- provide Thiamine/multivitamin/trace element
supplementation
- start nutrition support at 5-10 kcal/kg/day
- restore circulatory volume
- monitor fluid balance and clinical status
- replace PO 4 2- , K +and Mg 2+
- Reduce feeding rate if problems arise
NICE Guidelines for Nutrition Support in Adults 2006 41.
IMMUNONUTRITION Human Evolution
- First 72 hours after severe illness or injury crucial
- Little hope of survival past this; not desirable
- Significant stores of stress substrates not necessary e.g.
glutamine
42. The Immune System
- A complex and interactive biological system that coordinates
the detection, destruction and elimination of any foreign material
or organism entering the body.
- Oxidants: cytokines, NFkB, genes, inflam n
- Nutrients: glutamine, FFAs, protein
- Glutathione: oxidant defence
- Anti-inflammatory molecules: attenuation
43. Critical Illness
- Sepsis: Battle between inflammatory response and
microbes/toxins
- Trauma: SIRS to non-infectious insult
- Minor insult: inflammatory response wins
- Major insult: with support (antibiotics, fluids) body may be
able to fight insult but in severe insult inflammatory response
continues and causes organ damage, f/b immune paresis and 2
infection; death
44. THE ICU GAMBLE How to tip the scales? Inflammation,organ
failure Inflammation and resolution DEATH LIFE DISABILITY 45.
Critical Illness
- Small reductions in mortality over years
- Increasing problems with infection
- Advances in treatment have limited effects
- The future: replacement of the bodys own stress substrates
- Could immunonutrition be the most important area in critical
care development?
46. Failed ICU strategies
- Steroids in sepsis recent work suggests little effect
- NO synthetase inhibitor: increased mortality
- ??? Activated protein C - controversial
47. Immuno/Pharmaconutrition
- Disease-modulating nutrients
- Attenuate metabolic response
- Favourably modulate immune response
- Probiotics to alter gut environment
- Glycaemic control: keep blood glucose oxidation
- Acute stress: injury/sepsis causes acute dysregulation:
ROS/RNOS formed
- Mitochondria are both sources and targets
- Observational studies: anti-oxidant capacity inversely
correlated with disease severity due to depletion during oxidative
stress
REDUCTION OXIDATION 64. Reactive Oxygen Species O - , NO -
- Regulation of vascular tone
- Cell injury (ischaemia /reperfusion)
OXIDATION REDUCTION 65. ACUTE INSULT Exacerbation of cell and
tissue injury Inflammatorymediators ROS/RNOS Healing/repair/defence
66. Antioxidants
- Glutathione, Vitamins A, C and E
- Zinc, copper, manganese, iron, selenium
- Should we give extraCCCN consider
- Results of SIGNET and REDOXs awaited
- Oxidative stress in critically ill patients contributes to
organ damage / malignantinflammation
67. Which Nutrient for Which Population? Canadian Clinical
Practice GuidelinesJPEN 2003;27:355 Recom-mend Omega 3 FFA Consider
Anti-oxidants EN Possibly Beneficial: Consider EN Possibly
Beneficial: Consider PN Beneficial Recom-mend Possible Benefit
Glutamine No benefit No benefit (Possible benefit) Harm(?) No
benefit Benefit Arginine Acute Lung Injury Burns Trauma Septic
General Elective Surgery Critically Ill 68. Immunonutrition- the
future?
- The right nutrient or combination
- The right patient and circumstance
- The appropriate assessment of efficacy
- Balance between harm and benefit of the immune response
- ?? Nutrient-gene interactions
69. Now
- More & better trials of Immunonutrition
- Early PN supplementation trial
- Meanwhile: the basics- screening, reaching goals, protocols,
refeeding
- Profile of Nutrition: Education, dialogue
70. Maintains Stimulatesthe environment defences