5/30/2014 Disclosures NONE Nutrition in the ICU Lee-lynn Chen - - PDF document

5/30/2014 1

Nutrition in the ICU

Lee-lynn Chen May 30, 2014

Disclosures

• NONE

Objectives

• Define health care associated malnutrition
• Review evidence related to optimal nutrition
• List strategies to improve nutritional adequacy

in the ICU setting

Health Care Associated Malnutrition

• Occurs in a health care facility
• Nutritional deficiencies that are iatrogenic
• Subsequent physiological derangement and/or
• rgan dysfunction
• Caveat –

– Early and adequate nutrition can modulate the underlying disease process and improve patient

• utcomes

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Scope of Issue

• Incidence of malnutrition ranges 25-75%
• Malnutrition contributes to morbidity/mortality
• Nutritional status declines with length of stay
• Early identification and intervention can lead to

cost-effect and beneficial outcomes

NUTRIC Variables NUTRIC Scoring System

Relationship between nutritional intake and mortality

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Metabolic Response to Stress

• Nutrition supplies substrate for metabolic needs
• Acute critical illness

– Catabolism exceeds anabolism – Fat mobilization is impaired – Carbohydrates are preferred fuel source – Goal is to mitigate muscle protein breakdown

• Hormones
• Protein Messengers/Cytokines

Hormonal Response

• Glucagon

– Stimulates gluconeogenesis

• Cortisol

– Increases net protein catabolism

• Catecholamines

– Glucose intolerance / insulin resistance

Role of Cytokines

• TNF, IL-1, IL-6

– Fever, hypotension, inflammation – Accelerate skeletal muscle proteolysis – Increase metabolic rate – Stimulate & release acute phase reactants (CRP, ferritin, ceruloplasmin) – Depress hepatic protein synthesis (albumin, pre- albumin, transferrin)

Overall Metabolic Effect on Stress Response

• Increased energy expenditure
• Weight loss
• Anorexia
• Increased Urinary Nitrogen Losses

– 20-30 grams nitrogen / day

• Profound reduction in lean body mass

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Importance of Appropriate Nutrition

• Reduce infectious complications

– Maintain immunocompetence – Enhance wound healing process – Prevent bacterial translocation

• Decrease length of stay & healthcare cost
• Decrease mortality

Goals of Nutrition Therapy

• Well-balanced fuel mix

– 30% fat, 20% protein, 50% carbohydrate

• Maintain lean body mass
• Provide substrates for tissue repair
• Support hepatic protein synthesis
•  morbidity and mortality
• Optimize outcomes (cost and length of stay)

Who should not be fed?

• Non-functioning GI tract
• Shock Liver
• Hemodynamic instability
• Aggressive therapy not warranted

Feeding Patients on Vasopressors

• Controversial
• MAP > 60
• Shock - induced gastroparesis may limit effectiveness
• f gastric feeding
• Evidence supports feasibility of EN
• ? Enteral administration of glutamine in setting of gut

hypoperfusion

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ICU patients on pressors and MV

DiGiovine et al. AJCC 2010

Timing of Feeding

• Timing significantly affects degree to which GI

integrity protected or maintained

• Bowel sounds should not be used to indicate

feasiblity of enteral feeding

• Numerous studies comparing early (within 24-

36 hours) vs. delayed (>48 hours) feeding showing positive clinical outcomes

Calculations

• Anthropometrics

– Usual body weight versus ideal body weight – 25-40 Kcal/kg – Predictive equations for resting energy expenditure (i.e. Harris-Benedict Equation)

• Other adjustments

– Multiply REE by stress factors

• Elective Surgery 1.2
• Sepsis 1.2 – 1.4
• Burns 1.8 – 2.5

Protein

• RDA=.8 gm pro / Kg ideal body weight (IBW)
• Critical illness: 1.5-2.0 gm / Kg
• Moderate protein provision with ARF

– No dialysis (.8-1.2 gm / Kg IBW) – ARF/CRF(hemodialysis)=1.2-1.5 gm/Kg

• Provide greater protein with CRRT

– CAVHD/CVVHD=1.6-1.8 gm /Kg

• Protein restriction with liver failure

– Moderate restriction 1.0-1.2 gm / kg – No major benefit of limiting protein intake – Low protein diet did not have consequence on liver function or ammonia levels

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Assessment

• Normal protein levels

– Albumin (3.5-5 gm/dL) – Pre-albumin (20-40 mg/dL) – Transferrin (200-400 mg/dL)

Pre-Albumin

• Short half-life; small protein pool
• Sensitive indicator of refeeding
• Not greatly affected by fluid shifts
•  in acute stress or infection
• Trend CRP & Prealbumin

Effectiveness of Therapy

• Serum visceral proteins (track

trend) – Albumin, prealbumin, CRP

• Nitrogen balance studies
• Indirect calorimetry studies

Critical Care Nutrition Guidelines 2013

• The Canadian Critical Care/ASPEN Guidelines
• Reviewed 120 new RCT
• Updated recommendations

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Trophic Feeding

• Is there a minimum feeding rate needed?
• Maybe in animal studies
• No definitive human studies
• Likely need approximately 60% of goal feedings

to obtain desired effect

• Recent study showing no worse outcome
• Recommendations are to avoid trophic feeding

as the initial strategy

Targets

• Caloric goals
• Protein goals
• PEP UP study demonstrated decreased

mortality in patients who were fed with more calories and more protein

• New initiatives to target 24 hour totals

– Targeting volume based feeding protocol now

• More information to come

Enteral vs Parenteral Route

• Enteral feeding preferred over parenteral

nutrition –  infectious complications – Maintenance of more “physiologic” state of the GI tract – Reduce or contain stress response – Nitrogen sparing &  weight loss – Higher visceral protein levels – Less expensive

Basic guidelines

• EN superior to PN
• Start EN early within 24-48 hours
• Indirect calorimetry vs predictive equations –

insufficient data

• Consider polymeric formulas
• Prokinetic agents (metoclopramide) may be

helpful and tolerating higher residual volumes

• HOB elevated to 45 degrees when possible

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Gastric vs Small Bowel Feedings

• Best method of delivery remains controversial
• Several studies suggesting gastric feedings

safe in ICU patients

• Several studies showing safer to administer

enteral feeds past the pylorus

• Most recent studies show no significant

difference in aspiration but small bowel feedings provided more nutrient intake

Small bowel feedings

• Recommend small bowel feedings when

feasible

• Consider for patients at high risk for intolerance

to EN (on inotropes or sedative, high NG tube drainage or nursed in the supine position)

Infectious Complications of Parenteral Nutrition

• Increase in hyperglycemia
• Increased permeability of GI mucosa to bacteria

and enteral toxins

• Reduction in mucosa immunity

PN

• Strongly recommend against the use of PN and

high IV glucose

• Should only be started after all enteral options

have been exhausted

• Utility of supplementing inadequate enteral

nutrition with PN is still in question

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Pharmaconutrition

• Variety of specialized formulas available for

isolated organ failure or specific disease processes

• Expensive
• Limited data to support impact on patient
• utcome preclude use
• Standard formulas usually acceptable

Glutamine

• Central to cellular energy, cell proliferation and

acid/base regulation

• May be beneficial

– Preferred fuel source in enterocytes – Promotes protein synthesis in gut mucosa – Precursor for glutathione – Intraluminal gln reverses shock-induced splanchnic vasoconstriction

Glutamine

• When PN is prescribed for critically ill patients,

glutamine should be considered (especially burn and trauma)

• Insufficient evidence supporting IV glutamine

supplementation to critically ill patients receiving EN

• REDOX Study - strongly recommends against

glutamine (EN and PN) use in critically ill patients with shock and MOF

Arginine

• Essential amino acid
• Precursor for nitric oxide
• Stimulates processes (regulates)

– Collagen synthesis – Glucose clearance – Lymphocyte function

• Should not be used not be used for critically ill

patients (4 level 1 and 22 level 2)

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Use of enteral formula with fish oils borage oils and antioxidants

• Fatty acids converted to eicosanoids during

stress (i.e. pro-inflammatory)

• w-3 promote less inflammatory eicosanoids
• 2 level 1 studies and 5 level 2 studies
• Considered in ALI and ARDS patients
• Potential reduction in pressure ulcer
• Insufficient data to support supplementation

alone in critically ill patients

Selenium

• Essential trace mineral with antioxidant and anti-

inflammatory effects – Glutathione – Iodine – Thyroid Metabolism

• Decrease mortality – no difference

in LOS

• Use of IV/PN selenium

supplementation alone or in combination with other antioxidants should be considered in critically ill patients

Take Home Messages

• Audit your nutrition practice
• Standardize Care
• Identify Barriers to feeding patients
• Improve Nutrition Knowledge
• Be a Nutrition Champion

QUESTIONS?