Dose of Macronutrients

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Dose of Macronutrients

• Cathy Alberda, MSc, RD
• Royal Alexandra Hospital
• Edmonton, AB
• May 31, 2008

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Objective

• To explore the relationship between pre-ICU
  nutritional risk, amount of nutrition therapy
  (energy protein) and clinical outcomes in
  critically ill adults

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What we do know

• Early enteral nutrition impacts outcome of ICU
  patients in a favorable manner
• Disease states of critical care can alter
  nutritional requirements and exacerbate
  deficiencies
• A relationship exists between nutrient
  deficiency, altered immune status and clinical
  outcomes

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What we dont know

• The optimal amount of energy and protein a given
  ICU patient should receive
• The Debate Cumulative energy deficit associated
  with adverse clinical outcomes vs hypocaloric
  feeding beneficial

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Observational Studies on Hypocaloric Nutrition

• 48 critically ill patients
• Adjusted for SAPS II Score, SOFA score, BMI, age
• ? Caloric debt associated with
• ? Longer ICU stay (p0.001)
• ? Days on mechanical ventilation (p0.0002)
• ? Complications (p0.0003)

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Observational Studies on Hypocaloric Nutrition

• 138 medical ICUs patients (92 mechanically
  ventilated)
• Daily caloric intake grouped into quartiles
  according to ACCP recommended levels of caloric
  intake
• Lowest quartile (lt6 kcal/kg/day) ? risk
  bloodstream infection
• gt25 recommended caloric intake ? risk of
  bloodstream infection

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Observational Studies on Hypocaloric Nutrition

• 187 critically ill patients
• Tertiles according to ACCP recommended levels of
  caloric intake
• Highest tertile (gt66 recommended calories) vs.
  Lowest tertile (lt33 recommended calories)
• ? in hospital mortality
• ? Discharge from ICU breathing spontaneously
• Middle tertile (33-65 recommended calories) vs.
  lowest tertile
• ?Discharge from ICU breathing spontaneously

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More of what we dont know

• Relationship between nutritional risk at
  admission to ICU, nutrition therapy and
  subsequent outcome has never been studied
• 24 randomized trials of EN vs PN or early vs late
  EN none considered premorbid nutritional status
• Work in non-ICU patients has demonstrated the
  relationship between nutritional status and the
  potential effect on outcomes ? Application to
  ICU patients

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2007 International Observational Study

• Point prevalence survey of nutrition practices in
  ICUs around the world conducted Jan. 27, 2007
  conducted by CERU, Kingston
• Enrolled 2772 patients from 158 ICUs over 5
  continents
• Included ventilated adult patients who remained
  in ICU gt72 hours

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Patient data collected

• Diagnosis
• Surgery vs medicine
• Age, sex, BMI, APACHE II score, baseline
  nutritional assessment TPN vs EN
• Daily intake of energy, protein x 12 days
• Outcomes at 60 days

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Hypothesis

• There is a relationship between amount of energy
  and protein received and clinical outcomes
  (mortality and of days on ventilator)
• The relationship is influenced by nutritional
  risk
• BMI is used to define chronic nutritional risk

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Nutrition Therapy of ICU patients in ICU longer
than 72 hours
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60 day mortality relative to BMI
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Results

• Significant relationship between mortality and
  total calories, calories per kg, total protein,
  total protein per kg and age

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Each grid on the calories and BMI axes represent
100 calories and 1 kg/m2 respectively.
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Ideal BMI for ICU patients
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Biggest impact of feeding ICU patients

• 1stBMI lt20
• 2ndBMI 20-lt25
• 3rdBMIgt40
• Patients with BMI between 25 and 40 were
  relatively unaffected by feeding energy or protein

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Limitations of this observational study

• No acute marker of nutritional risk
• Patients with BMIs between 25-40 may still
  present with nutritional risks, but were not
  reflected in study
• These same patients may have benefited from
  increasing amounts of nutrition but study design
  did not detect
• BMI gross indicator only

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The bottom line

• amount of energy and protein intake does impact
  mortality in patients with BMIs lt25 and gt40
• Affect of nutrition therapy impacted by
  pre-existing nutritional status

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Caution

• Remember this is an observational studyunable to
  make strong clinical inferences, however
• Hypothesis increasing nutrient provision in the
  early phase of critical illness may be associated
  with improved clinical outcomes, particularly in
  lean and obese patients

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What is the optimum amount of nutrition for this
patient?

• To answer this question, further high quality
  evidence from RCTs is required

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ICU patients are not all created equalshould we
expect the impact of nutrition therapy to be the
same across all patients?
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• Feeding patients with different BMIs
  nutritional risk levels needs to be considered
  for its role on clinical outcomes in the
  critically ill

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Top Up Trial RCT Proposal

• Goal to design a prospective randomized trial to
  determine the impact of amount of energy
  protein received on clinical outcomes in
  mechanically ventilated ICU patients
• Preliminary findings suggest that nutrition
  therapy will have different impacts in different
  patient groups BMI must be lt25 to be considered
  for inclusion in this trial

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Study Intervention

• Control Group
• Standard EN therapy within 48 hrs ICU admission,
  advance as per hospital protocol

• Study Group
• Initiate EN as per hospital protocol if patient
  fails to meet target by 72 hrs of ICU admission,
  supplement with TPN

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Study Intervention, contd

• Control Group
• Continue EN trials for first 12 days of ICU
  admission if intake less than desired,
  additional nutrition from TPN will not be
  considered
• Tight glycemic control

• Study Group
• Continue EN/PN combination or full EN (if
  tolerated) x 12 days
• Intake not to exceed 35 kcals/kg
• Tight glycemic control

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Outcomes

• Mortality 30 d and 60 d
• Duration of mechanical ventilation
• LOS (ICU and hospital)
• Multiple organ dysfunction
• Development of infections

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