SEMINAR
SEPTEMBER DM 23, 2005
NUTRITION IN ICU
Navneet Singh
Department of Pulmonary
Medicine
Scope of seminar
Introduction
Assessment of nutritional status
Provision of nutritional support
Enteral & Parenteral Nutrition
Obesity & ICU
Immunonutrition
Nutrition Protocols
Introduction
Critical illnesses, stress & surgery place
demands on bodys nutritional req. promote a
catabolic state & -ve N balance.
Prolonged bed rest & inactivity per se
-ve N
balance in healthy individuals
Bloomfield SA. Med Sci Sports Exerc. 1997; 29(2): 197-206.
Combination of hypermetabolic state like critical
illness or sepsis + bed rest & inactivity
suitable environment for occurrence of
malnutrition
Introduction
Malnutrition - net nutrient intake < net
nutrient req
1% to 15% of ambulatory outpatients
25% to 60% of institutionalized patients
35% to 65% of hospitalized patients
Uncorrected it is succeeded by metabolic
abnormalities, physiologic changes,
reduced organ & tissue fx & loss of body
mass
OPTIMAL NUTRITIONAL STATUS
& FACTORS INFLUENCING IT
SE Status, Disease,
Cultural Factors,
Emotional Status
Nutrient Intake
Physio. Stress (Preg, Growth)
Psychological Stress
Path. Stress (Fever, Disease)
Nutrient Requirements
Disease
Reduced Intake
Losses (GI, Ur)
Altered Requirements
Deficiency
Inefficient Fuel Utilization
Reduced mass
Change in Body Composition
Change in Physiologic
& Metabolic Responses
Loss of reserve tissue
& functional capacity
Loss of Homeostasis
Introduction
Effect on Liver:
Increased production of acute phase proteins
Decreased production of albumin
Increased catabolism of albumin
Extravasation of albumin into extravascular space
Effect on Lungs :
Decreased diaphragmatic muscle mass
Decreased max voluntary ventilation
Decreased max mouth pressures
Breathing pattern (Rapid shallow)
Increased Fluid in Interstitium
Decreased FRC & predisposition to atelectasis
Introduction
Feature
BMR/REE
Resp. Quotient
Cytokine levels
Primary fuels
Proteolysis
Ureagenesis
Ur N losses
Gluconeogenesis
Ketone production
Starvation
(0.6-0.7)
Fat
+
+
+
+
+++
Catabolism in
Critical Illness
(0.8-0.9)
Mixed
+++
+++
+++
+++
+
Introduction
Demling RH, DeSanti L. Curr Opin Crit Care 1996; 2: 482491
Introduction
Factors adversely influencing outcome in
critical illness
Depleted lean body mass
Male gender
Insulin insensitivity
Impaired anti-oxidant defences
Immunosuppression
Hyper inflammatory state
Ageing
Disadvantageous genotype
Grimble RF. Curr Opin Gastroenterol 2005; 21: 216222
Introduction
Malnutrition in ICU patients can be either
present on admission or develop subsequently
as a result of metabolic response to injury
Whatever the cause the end result is the same
i.e. malnourished pts tend to have longer
hospital LOS
costs of care & mortality
Middleton MH et al. Intern Med J. 2001; 31(8): 455-461.
Nutritional suppl
halt catabolism
malnutrition
opportunity to slow down or
restore N balance
prevent
Nutritional Assessment
Nutritional Assessment
History:
Medical (ch debilitating diseases & psy disorders)
Socioeconomic
Dietary/nutritional
Drug abuse & alcoholism
Physical Examination:
Nutrition focused physical examination
Anthropometry
Body composition & circumference measurements
Laboratory Investigations:
Biochemical
Immunologic
Nutritional Assessment
Body Weight:
Unintentional loss of usual BW by >10% in 6 m
(or >5% in 1 m) clinically significant & suggestive
of malnutrition
Problems with BW:
Critically ill pts often edematous (water & salt
retention)
BW changes usually reflect fluid shifts &
not changes in actual body cell mass
Based on comparison with a wide range of N values
compounded by presence of diversity in control
population
Nutritional Assessment
1. Ideal BW: comparison of ABW with IBW more
useful than ABW alone
IBW (M) = 106 lb for 5 ft height + 6 lb/ each addl inch
IBW (M) = 47.3 kg for 150 cm height + 2.7 kg/ each addl 2.5 cm
IBW (F) = 100 lb for 5 ft height + 5 lb/each addl inch
IBW (F) = 44.6 kg for 150 cm height + 2.2 kg/each addl 2.5 cm
Add or subtract 10% for large & small frames resp
2. BMI: Useful for grading malnutrition &
prognostication
Nutritional Assessment
BMI (in kg/m2) Nutritional Status
>30
Obese
25-30
Overweight
20-25
Normal
<18.5
Mild & moderate malnutrition
<16
Severe malnutrition
<13
Usually incompatible with life (M)
<11
Usually incompatible with life (F)
Henry CG. BMI & limits of human survival. Eur J Clin Nutr 1990; 44: 329-335
Nutritional Assessment
Anthropometric measurements:
Objective evaluation of fat & LBM/skeletal proteins
Safe, simple & inexpensive
Can be done at bedside
? Reliability Accuracy of detecting ac changes esp
critically pts who receive aggressive fluid
resuscitation
1. Skinfold thickness
Based on assumption that 50% of total body fat is
s/c (vary from 20-70% in N subjects)
Nutritional Assessment
Commonly triceps used (subscapular/ iliac crest/
N values = 12.5 mm (M) & 16.5 (F)
upper thigh)
Over & under-estimation of body fat in malnourished
& obese pts respectively
2. Mid upper arm circumference ( MUAC ):
Mid-point b/w acromion & olecranon
3. Mid arm muscle circumference:
= MUAC { x TSF }
N values = 25.5 mm (M) & 23.0 mm (F)
4. W/H ratio
Nutritional Assessment
Serum Albumin
Serum half life 20 d
Neither sensitive nor specific as a std for
nutritional assessment
In addition to nutritional status, affected by:
Hepatic fx
Protein loss
Hydration status
Changes in distribution b/w intra & extravascular
compartments incl exudation at the capillary level
Infection/infl
Better marker of disease severity than nutritional
status?
Nutritional Assessment
Serum Albumin
Hypoalbuminemia an imperfect measure of
nutrition but an excellent marker of injury?
Levels indicate catabolism (cytokine mediated)
Levels correlate inversely with other markers of infl
Rate of fall may be as high as 50% in 2 d of ac phase
of sepsis & can relate to mortality
Levels not expected to despite nutritional intake
unless stress response subsides
Attempts at
correction of hypoalbuminemia by i/v admn of albumin
not assoc with improved clinical outcomes
Serum proteins in critical illness
Fleck A. Br J Clin Pract Suppl 1988;63:204;
Nutritional Assessment
Serum Albumin
Control of stress
levels can by upto 10%/ day
with adequate nutr support
may be N by 2 wks
However despite the concerns regarding its
usefulness, serum albumin remains one of the
most powerful nutritional markers & outcome
predictors in hospitalized patients & critical
illness
Lafrance JP et al. Metabolic, Electrolytes & Nutritional
Concerns in Critical Illness. Crit Care Clin 2005; 21: 305327
Nutritional Assessment
ALC:
Levels <1000/uL ? depletion of T cell rich areas of
RES & assoc with cutaneous anergy
Pre albumin:
Produced primarily in liver (others choroid plexus &
enterochromaffin cells in GI mucosa)
Normal levels: 6 to 35 mg/dl
? Better marker of malnutrition
Short serum t (2 days)
Less affect by liver disease than other proteins
Not affected by hydration status
Not affected by vitamin deficiency (except zinc)
Negative acute phase reactant
Nutritional Assessment
SGA (Subjective Global Assessment):
Based on assumption that history/physical
exam assesses nutritional status more
precisely & is better predictor of
morbidity/mortality than any lab test
History:
Physical Exam:
Wt change
Dietary intake change ( ~ N)
GI symp (> 2 wks)
Functional capacity
Loss of s/c fat
Muscle wasting
Ankle & sacral edema
Ascites
Nutritional Assessment
Divided into
Class A :< 5% wt loss or > 5% wt loss + recent gain &
improvement in appetite
Class B : 5-10% wt loss without recent stabilization or
gain, poor dietary intake & mild loss of s/c tissue
Class C: ongoing wt loss of >10% with severe s/c
tissue loss & muscle wasting often with edema
Other Nutritional Indices:
Prognostic Nutritional Index (PNI) combines
measurements of S. Albumin, S. Transferrin, TSF
Thickness & Delayed Cutaneous Hypersensitivity
Prognostic Infl & nutritional index (PINI) aggregates
S. levels of CRP, alpha 1-acid glycoprotein,
prealbumin & albumin
Nutritional Assessment
No single marker till date has been validated as
being ideal for assessing nutritional status of
critically ill patients i.e. there is no gold std:
No universally accepted clinical definition of
malnutrition
All currently available parameters for assessment of
nutritional status are affected by disease processes
Effects of malnutrition & of the disease itself on the
final outcome may be difficult to distinguish
There is paucity of data to compare different
commonly used nutritional assessment parameters
and hence sensitivity, specificity and reliability of each
vis--vis others cannot be defined
Klein S et al. J Parenter Enteral Nutr 1997; 21: 133-156
Provision of Nutritional Support
Provision of Nutritional Support
Goals/Principles of Nutr. Support to critically ill:
Provision of nutr support after taking into account:
Medical condition
Baseline nutritional status
Existing metabolic requirements
Route available for admn of nutrients (EN and/or PN)
Prevention (if possible) of nutrient deficiencies
(macro & micro) & Rx of existing ones
Avoidance of complications associated with
nutritional support
Improvement in pt outcomes (morbidity/mortality)
Provision of Nutritional Support
Indications
Presence of malnutrition (of any etiology) in a patient
unable to eat (Benefit of nutritional support best seen
in pts whose baseline nutritional status is < N incl pts
with BMI<16)
In well-nourished pts, prolonged fasting (>3-4 d) &
inability to resume oral nutrition (Such pts can often
tolerate short periods of starvation <1 week)
Supplementation if oral intake insufficient for >3-4 d
Provision of Nutritional Support
Sys review, 15 prospective RCTs, n=753
Adult ICU pts (post-op, trauma, head-injury &
burns) - No study on MICU pts
Compared early EN (initiation of nutr support in
< 36 hrs) to delayed EN (>36hrs)
Early EN assoc with:
infection rates (RR = 0.45)
Hosp LOS
mortality (8% vs 11.3%, RR=0.74 NS)
No diff w.r.t non-infectious complications
Marik PE et al. Crit Care Med 2001; 29(12): 2264-2270
Provision of Nutritional Support
Calories:
TEE = REE x activity factor
REE (BMR):
Harris-Benedict equation
Males = 66.5 + 13.75W + 5.003H 6.775A
Females = 655.1 + 9.563W + 1.850H 4.676A
W = Wt in kg, H = Ht in cm & A = age in yrs
Males = 25 kcal/kg OR 900 + 10 x weight (kg)
Females = 22 kcal/kg OR 700 + 7 x weight (kg)
10%/C rise in temp
by 40 100%
Sepsis
Starvation
by 20 40%
Fever
Provision of Nutritional Support
Activity factor:
1.2 (sedentary), 1.4 (moderate) & 1.8 (heavy)
Indirect calorimetry:
Measures REE from O2 consumption (VO2) & CO2
production (VCO2) in specified time period
REE (kcal/min) = C.O. x VO2 + 1.1 VCO2
REE (kcal/d) = REE (kcal/min) x 1440
Protein:
1.2-1.5 g/kg BW/d (max 1.8-2.0 g/kg BW/d in
pts with extreme protein losses
Fluid: Approx 1 ml of water per kcal administered
Enteral & Parenteral Nutrition
Enteral & Parenteral Nutrition
Whenever nutritional supplementation is
indicated, EN preferred to PN
Advantages of EN over PN:
incidence of mucosal atrophy & reduction in
intestinal permeability
Promotes gut motility
paves way for initiation of
oral feeding
translocation of bacteria from the gut
Avoids infectious complications assoc with PN
Less costly
More physiological
Jolliet P et al. Intensive Care Med 1998; 24: 848-859
Enteral & Parenteral Nutrition
Contraindications to EN:
Absolute
Nonfunctional gut: anatomic disruption, obstruction, gut
ischemia
Generalized peritonitis
Severe shock states
Relative
Expected short period of fast, except in severely injured
patients
Abdominal distension during EN
Localized peritonitis, intra-abdominal abscess, severe
pancreatitis
Early EN vs Early PN
Meta-analysis of trials comparing early EN vs
early PN in hospitalized pts
30 RCTs (10 medical, 11 surgical & 9 trauma)
No diff b/w groups in terms of hospital mortality
(applicable for subgroups also)
PN
incidence of infective (incl CRBI) &
noninfective complications & Hosp LOS
EN assoc with in diarrhea
No effect of age, time to initiate Rx & av
albumin on mortality
Early EN ~ early PN does not mortality
Peter JV et al. Crit Care Med 2005; 33(1): 213-220
Enteral vs Parenteral Nutrition
Meta-analysis of 11 trials (complete F/U in 9) of
PN vs. EN in critically ill pts
Analysis based on intention to treat principle
Mortality benefit in favour of use of PN;
subgroup analysis
benefit from PN use
greatest in trials in which EN delayed (>24 hr)
Infectious complications increased with PN (6/9)
Grade B+ EB recommendation for PN use in
pts in whom EN cannot be initiated within 24 hr
of ICU admission or injury
Simpson F et al. Intensive Care Med 2005; 31: 1223
Enteral vs Parenteral Nutrition
Sys Review,13 RCTs, n=807
Compared EN vs PN for outcome of critically ill
adult pts
Heterogeneous population of ICU pts (head
trauma & injury, abd trauma, sepsis, cardiac
bypass or severe ac pancreatitis)
Use of EN ~ PN assoc with
in infectious complications (RR = 0.64)
in cost
No diff in mortality, MV duration or hosp LOS
Gramlich L et al. Nutrition 2004;20:843 848
Enteral vs Parenteral Nutrition
PN assoc with:
incidence of hyperglycemia
caloric intake (5/11)
No diff in mortality rate b/w pts on PN & BS vs
pts on EN & N BS
Data on baseline nutritional status NA
no
conclusion on its relation with outcome
EN should be the first choice for nutritional
support in the critically ill
Gramlich L et al. Nutrition 2004;20:843 848
Enteral + Parenteral Nutrition
Sys review, 5 RCTs, n=248, ICU (M + S), Burns
& Blunt Trauma pts
Compared EN + PN to EN alone (PN started at
same time as EN)
No diff b/w groups w.r.t mortality, rates of infection,
Hosp LOS or MV duration
+ EN PN
significant in cost & calorie delivery
In critically ill patients who are not malnourished
and have an intact gastrointestinal tract, starting
PN at the same time as EN provides no benefit
in clinical outcomes over EN alone
Dhaliwal R et al. Intensive Care Med 2004; 30: 16661671
Enteral & Parenteral Nutrition
PN remains a valuable yet challenging
weapon in our therapeutic armory in the
presence of GI feed intolerance or failure.
However it should be used wisely & not
indiscriminately because most intensive
care patients with a fully functional GIT
may be fed safely with EN
Griffiths RD. Curr Opin Clin Nutr Metab Care 2004; 7:175-181
Obesity in ICU
Predicting energy needs in critical illness difficult
(uncertainties reg influence of diff factors on EE)
much more difficult in critically ill obese pts
Although morbidly obese patients have excess
body fat stores, they are prone to develop
protein malnutrition during metabolic stress
basal insulin level
suppression of lipid
mobilization from body stores
acc protein
breakdown for gluconeogenesis
rapid in
lean body mass (LBM) & in urea prod & Ur N
losses
Jeevanandam M et al. J Clin Invest 1991; 87: 262269
Obesity in ICU
Effect of obesity on ICU mortality
Retro study (n=117, 2 MICUs)
Morbidly obese pts (BMI>40) had req for MV, MV
duration, ICU LOS & overall mortality (30% vs 17%)
El-Sohl A et al, Chest 2001; 120:19891997
Prospective study (n = 813, single center)
BMI of 27 used to separate obese (n = 215) &
nonobese (n = 598) groups
Obese pts had higher ICU LOS, SAPS II score & ICU
mortality. Observed mortality of obese pts > mortality
predicted by SAPS II scores
Obesity in ICU
Multivariate analysis
SAPS II score & BMI > 27
predictive of ICU mortality
Current prognostic scoring systems do not include
BMI/obesity though high BMI value is an independent
predictor of high ICU mortality
These
underestimate the mortality risk for obese patients
Goulenok C et al. Chest 2004; 125: 14411445
Prospective study (n= 2148)
No effect of BMI on APACHE II scores, mortality, ICU
LOS, hospital LOS, % req MV, days on MV, total cost
or adverse events
BMI has minimal effects on ICU outcome
Ray DE et al. Chest 2005; 127: 21252131
Obesity in ICU
SUPPORT (Study to Understand Prognoses &
Preferences for Outcomes & Risks of Rx)
Prospective, multicenter study (n = 4301)
5 tertiary care medical centers
Pts >18 yrs + anticipated 6 m mortality = 50%
BMI <15th percentile assoc with 6 m mortality (risk
ratio = 1.23)
High BMI (>85th percentile) not assoc with
significantly risk of mortality
Galanos AN et al. Crit Care Med 1997; 25:1962-1968
Obesity in ICU
Retrospective analysis (n = 41011, Multicenter)
Divided into 2 groups depending whether SAPS II or
mortality prediction model [MPM] used
Underweight (BMI <20)
mortality + ICU &
hospital LOS + Impaired fx status at discharge
Overweight (BMI = 25-30)
disability at discharge
Obese (BMI = 30-40)
ICU & hospital LOS (SAPS)
BUT disability at discharge (MRM)
ICU & hospital LOS
Severely obese (BMI > 40)
Overweight & Obese Pts may have mortality &
improved functional status at discharge
Tremblay A et al. Chest 2003; 123: 12021207
Obesity in ICU
Which weight to use?
ABW vs IBW
65 hospitalized & 65 non hospitalized obese
adults (ABW >130% IBW, ~ all pts on EN/PN)
EE predicted better by using ABW ~ IBW
Ireton Jones et al. J Am Diet Assoc 1991; 91: 93-95
Obesity Adjusted Wt (OAW)
Developed for more accurate prediction of
LBM in obese pts
OAW = IBW + 0.25 (ABW IBW)
Obesity in ICU
OAW vs ABW
Energy needs predicted with Harris-Benedict
equation (HBE) & kJ/kg (KPK) strategies
(using both ABW & OAW)
Results compared with measured EE
determined by indirect calorimetry
Use of ABW
overfeeding
Use of OAW + KPK strategy
more accurate
energy predictions ~ HBE
OAW + KPK strategy preferable for obese pts
( 130% of IBW)
Cutts ME et al. Am J Clin Nutr 1997; 66: 12501256.
Obesity in ICU
Eucaloric vs hypocaloric EN
40 critically ill, obese pts admitted to
trauma/SICU (ABW > 125% of IBW)
Eucaloric feeding ( 20 kcal/kg/d of OAW) or
hypocaloric feeding (>20 kcal/kg/d of OAW)
Protein intake for both ~ 2 g/kg/d (IBW)
Hypocaloric group:
Shorter ICU LOS
Duration of Antibiotic Rx
Duration of MV (NS)
Dickerson RN. Nutrition 2002; 18(3): 241-246.
Obesity in ICU
Indirect calorimetry to determine EE :
Req FiO2 <0.6
Erroneous values:
System leaks
Abnormal water vapor pressure
Errors in calibration
Current recommendation:
OAW + KPK strategy
20 30 kcal/kg/d (OAW)
1.52.0 g/kg/d (IBW)
El-Solh AA. Am J Respir Crit Care Med 2004; 169: 557561
Immunonutrition
Immunonutrition
Nutritional deficits produce significant atrophy of
lymphoid organs & impaired fx
Malnutrition (& impaired immune fx) common in
hospitalized patients
adverse effect on
recovery
The administration of nutrients that have nutritive
and pharmacological effects (immunonutrition)
can counteract this and improve patient outcome
Immunonutrients are specific nutrients that exert
immune enhancing effects independent of their
energy/protein value (include arginine,
glutamine, nucleotides & -3 FA)
Immunonutrition
-3 FA + med chain TGs + olive oil
alt to -6 FA (pro-infl effects)
as I/V lipid suppl
Oxidative fuel for lympho & macro.
During stress, exogenous glutamine
reqd to avoid catabolism & muscle
glutamine depletion
Stimulation of macrophages
& NK cells fx
Grimble RF. Immunonutrition. Curr Opin Gastroenterol 2005; 21: 216222
Antioxidants/-3 FA &
Oxidative/Inflammatory Stress
Grimble RF. Immunonutrition. Curr Opin Gastroenterol 2005; 21: 216222
Immunonutrition
Linoleic acid
6 PUFA
Major constituent of cell membranes
Precursor of prostanoid & LT synthesis
No parenteral forms available
Trace Elements
Zinc reqd for biologic activity of thymic hormone (T cell
maturation)
Def assoc with intractable infections
Copper
Effects on T & B cell function
Selenium def
Ab responses
Other trace elements & antioxidants shown in vitro to
modulate activity of various immune cells
Slone DS. Crit Care Clin 2004; 20: 135157
Immunonutrition
What is clear about Immunonutrition?:
Efficacy better when admn through EN > PN
Efficacy better when admn to malnourished pts
What is unclear?
Is it efficacious at all?
Immunonutrition
Meta-analysis, 11 RCTs, n=1009
Comparison of EN + key nutrients vs std EN in
pts with critical illness & cancer
Results:
in infectious complications
hosp LOS
No diff in mortality
No diff in incidence of pneumonia
Heys SD et al. Ann Surg. 1999; 229(4): 467-77
Immunonutrition
Outcome
Mortality
Infection
Hosp LOS
No of trials
Overall Medical
12
3
8
1
10
2
Effect of ImN
Overall
Medical
NS
NS
NS
S
HS
S
ICU LOS
6
2
NS
NS
Days on MV
5
2
NS
S
Comparison of outcome with std EN vs commercially available
immune-enhancing EN feeds (arginine glutamine, nucleotides
& -3 FA) in critically ill pts after trauma, sepsis or major surgery
Sys review (12 RCTs, n=1482), analysis on intent-to-treat basis
Beale RJ et al. Crit Care Med 1999; 27:2799-2805
Immunonutrition
Outcome
Mortality
Infection
Hosp LOS
No of trials
Overall Medical
22
13
18
9
17
8
Effect of ImN
Overall
Medical
NS
NS
NS
S
S
S
Comparison of outcome of std EN vs EN + immune enhancing
nutrients in pts of elective surgery & critically ill pts after trauma,
burns or in ICU, Sys review (22 RCTs, n=2419)
Use of formulas other than high arginine content
mortality
& hosp LOS (overall & critically ill pts)
infection (overall)
Use of high arginine content formulas
& hosp LOS (overall & critically ill pts)
Heyland DK et al. JAMA 2001; 286: 944-953
Immunonutrition
Sys review of effects of std EN vs diets enriched
with pharmaconutrients
26 RCTs surgical (9), trauma (7), burns (2) &
mixed/ICU (8) n=?
Overall: Pts in pharmaconutrition group had
Incidence of HAP (11, OR=0.54)
Incidence of bacteremia (9, OR=0.45)
MV duration (7), ICU LOS (8) & Hospital LOS (12)
No diff in mortality (18) overall & subgroup
analysis
No diff in incidence of sepsis (5) or UTI (10)
Montejo JC et al. Clin Nutr. 2003; 22(3): 221-233
Immunonutrition
No e/o total no of infected pts during ICU
stay (ONLY incidence of some infections in
some groups)
Mixed group No MV duration, Hosp LOS or
ICU LOS in pharmaconutrient group
Marked heterogeneity in patient characteristics
as well as methodology/designs of trials
Considering some beneficial effects &
absence of detrimental ones, these diets could
be recommended in ICU pts requiring EN
(Grade B recommendation)
Montejo JC et al. Clin Nutr. 2003; 22(3): 221-233
Immunonutrition
Prospective DB RCT
2 ICUs, Netherlands
Heterogeneous population of pts expected to
require EN > 48 hrs (n =597)
Randomized to receive Immunonutrition (highprotein enteral formula enriched with arginine,
glutamine, 3-FA & antioxidants) or an
isocaloric control formula
Intention to Rx analysis
Kieft H et al. Intensive Care Med. 2005; 31(4): 524-532
Immunonutrition
No diff b/w groups w.r.t.:
Hosp LOS
ICU LOS
MV duration
ICU mortality
Hosp mortality
Infectious complications
Largest RCT on immunonutrition
in a general
ICU population immunonutrition has no
beneficial effect on clinical outcome parameters
Kieft H et al. Intensive Care Med. 2005; 31(4): 524-532
Immunonutrition
Q: Why is there so much variability in
responsiveness to immunonutrition?
A: Genes for cytokines & other molecules that
influence infl may be affected by changes in
their promoter regions [single nucleotide
polymorphisms (SNP)]
diff in amount of
gene formed when activation occurs. In addition
to diff in pt profiles, SNPs may be an imp factor
determining efficacy & clinical outcomes of
immunonutrition
studies reqd to determine
exact nature of genomic factors that influence
immunonutrition
Immunonutrition
Reports of infl could counteract effect on
immunity & could even make overall responses
to immune enhancing diets harmful
Effects are potentially unpredictable in different
clinical settings
Avoid extrapolation of results
between disparate groups
Routine use of immune-enhanced formulas
cannot be recommended without further
research to define the underlying mechanisms
by which immunonutrition may be harmful & to
identify which ingredients have beneficial effects
Nutrition Protocols
Nutrition Protocols
Pros:
Era of EBM
Use of guidelines, clinical protocols
& recommendations
improved quality of care
(esp in critical care single intervention
dramatic consequences & amount of available info
> human decision-making limits)
Cons:
Shortage of large prospective RCT
limitation in
stringency of recommendations
? Compliance with tight stds of care
Imposition
of cookbook medicine
hampered freedom of
Mx of pts
Anorexia Protocolis (reluctance to use protocols)
Zaloga et al. Chest 2004 ; 125 : 11951196
Nutrition Protocols
Prospective observational study
Canada, 59 ICUs (n = 638)
Hypothesis: ICUs whose practice was more
consistent with guidelines would have greater
success in providing EN
Pts on MV > 48 hrs & ICU stay > 72 hrs
Av duration of observation 10 d
Adequacy of EN (received/prescribed calories) =
1.8-76.6% (av 43%)
Heyland DK et al. Crit Care Med 2004; 32(11): 2260-2266
Nutrition Protocols
Higher adequacy of EN assoc with:
Use of a feeding protocol
Early initiation of EN (>50% of pts within 1st 48 hrs)
Use of small bowel feedings or motility agents in
>50% of pts with high gastric residual vol
Inverse assoc with use of PN (> median)
Study confirmed hypothesis: ICUs that are more
consistent with clinical practice guidelines are
more likely to successfully provide EN support to
pts
could lead to better outcomes
Heyland DK et al. Crit Care Med 2004; 32(11): 2260-2266
Nutrition Protocols
Prospective study
USA, MICU/SICU of 2 teaching hospitals
Objective: To determine effect of implementation
of an EB nutritional Mx protocol in ICU
Included all pts with expected ICU stay > 48 h
n= 200, 100 pts in each group (before & after
implementation of protocol)
Pts in postimplementation group:
Fed more frequently via enteral route (adjusted OR =
2.4)
Shorter duration of MV
Barr J et al. Chest 2004; 125: 14461457
Nutrition Protocols
No diff between two groups:
Time to initiate feeding
Total caloric intake on d 4 of nutritional support
ICU LOS
Hospital LOS
Pts who received EN had risk of death (HR =
0.44)
Barr J et al. Chest 2004; 125: 14461457
Nutrition Protocols
ACCEPT (Algorithms for critical care
enteral & parenteral therapy) Trial
Multicentre, cluster RCT (n = 462)
Hypothesis: Use of EB algorithms for
providing nutritional support in ICU
improvement in pt outcomes
ICUs of 12 hospitals
Pts 16 yrs & expected ICU LOS > 48 hrs
ICUs stratified by hospital type & randomized
to intervention or control arms
Martin CM et al CMAJ 2004; 170(2): 197-204
Nutrition Protocols
Pts in intervention hospitals:
Received nutritional support on more no of days (EN
or EN/PN)
Had shorter hospital LOS
Had reduced mortality
No diff in:
ICU LOS
Time to initiate nutritional support
Total calories or protein delivered
No of days on which caloric goal achieved
Martin CM et al CMAJ 2004; 170(2): 197-204
Nutrition Protocols
Q: What if nutritional protocols are not established?
A:
Daily assessment of whether a pt can be fed, in
what way (EN/PN/mixed) and how much?
All health care professionals involved in care of
ICU pts (physician, nurse, dietician,
physiotherapist etc) should be involved in Mx of
nutritional support even when their levels of
interest and knowledge widely differ
Preiser JC et al. Crit Care Med 2004; 32(11): 2354-2355.
Summary
Nutrition is a very imp aspect of pt care in ac &
ch critical illnesses
Use of appropriate nutritional support is cost
effective by reducing complication rates &
duration of stay
EN confers an enormous financial advantage
over PN
Optimal nutritional support to prevent & Rx
nutritional deficiencies should become part of
routine Mx of ICU pts