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Program Information. Nutritional Support in the ICU. Sandra L Schoepfel MS RD RN CNSD Karl D Pilson MD Suresh Agarwal MD FACS Boston Medical Center Boston, MA. Rationale for Nutrition Support.

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  1. Program Information

  2. Nutritional Support in the ICU Sandra L Schoepfel MS RD RN CNSD Karl D Pilson MD Suresh Agarwal MD FACS Boston Medical Center Boston, MA

  3. Rationale for Nutrition Support • Limit catabolism – hypercatabolic state is driven by the underlying disease process and is not reversed by nutrition alone • Offset muscle wasting and starvation induced immune depletion – loss of 1% per day lean body mass = 2% per day skeletal muscle • Substrate for healing and preserve immune function • Increase survival • Nutritional therapy in the ICU is at best “supportive” – cannot reverse hypermetabolism

  4. Goals of Nutritional Support In The ICU • Early intervention (after resuscitation) • Ensure adequate enteral access • Support the metabolic response to injury and infection (bone marrow, acute phase proteins, wound healing) • Correct fluid, metabolic and acid/base abnormalities • Avoid overfeeding and hyperglycemia • ? reduce ventilator dependency

  5. Achieving Nutritional Goals in the ICU is Difficult • 1 year survey of ICU Nutritional Practice: • 3526 record feeding days were evaluated • Desired intake was only achieved 52% of days • Ideal protein intake achieved in 54% • Ideal energy intake achieved in 66% • Ideal volume intake achieved in 75% of patients • Binnekade JM. Crit Care 2005. Jun;9(3):R216-25

  6. Baseline Patient Assessment • No “single” test can be used as a completely reliable indicator of nutritional status • Evaluation of weight loss and previous nutrient intake before admission • Level of disease severity • Presence of comorbid conditions • Function of the gastrointestinal tract • Evaluation of biochemical indices • Measurement of body mass index

  7. Nutritional Assessment – A Difficult Task in the ICU • Medical, surgical and dietary history may be hard to obtain • Physical assessment may be confounded by volume resuscitation (surgery, burn, trauma, infection) • Problems with Nutritional Assessment in ICU Patients ParameterInvalidation Weight (BMI)Edema, fluids, diuretics AnthropometricsEdema, observer variability Albumin, Pre-AlbuminInfection, inflammation, injury, renal failure Nitrogen BalanceDrainage tubes, wounds, renal failure

  8. Factors That Increase Nutritional Risk • Involuntary loss or gain of > 10% of usual BW within 6 months or > 5% of usual BW in 1 month, or a weight of 20% over or under ideal BW • Presence of chronic disease • Increased metabolic requirements • Altered nutrient schedules (TF’s, PN) because of recent surgery, illness • Impaired ability to ingest or absorb food adequately for > 7 days

  9. Malnutrition • Recent surveys suggest that 33-53% of hospitalized patients suffer from moderate to severe malnutrition • Souba W. N. Eng J Med 1997;336-41 • Atalay BG. JPEN 2008 Jul-Aug;32(4):454 • Delgado AF. Clinics 2008;63(3):357 • Assume some degree of malnutrition exists or will develop in all patients • In the ICU: Malnutrition contributes to respiratory weakness, failure to wean from the ventilator, increased morbidity, mortality and hospital costs

  10. Protein Markers in the ICU • Traditional protein markers (albumin, prealbumin, transferrin, retinol binding protein) and may also be a reflection of the acute phase response and do not accurately represent nutritional status • Improvement in hepatic protein levels indicate recovery, although not necessarily nutritional recovery

  11. Stimuli for Stress Response • Loss of blood volume • Emotion/pain/fear • Temperature • Infection • Tissue injury

  12. Goals of Stress Response • Maintain energy substrates (GLUCOSE) • Maintain oxygen delivery • Minimize further injury...

  13. Greenfield 1997

  14. Response to Stress/Injury • Neurohormonal - "Counterregulatory hormones" • Glucagon • Epinephrine • Glucocorticoids • Inflammatory mediators • IL-1, IL-2, IL-6 • TNF-a • IFN-g

  15. Metabolic Response During Sepsis – Carbohydrate Metabolism • Pro-inflammatory cytokines potentiate the release of catabolic hormones (glucagon, catecholamines, and cortisol) stimulating glycogenolysis and gluconeogenesis to mobilize glucose • Following the onset of sepsis, glycogen stores are depleted within hours, and endogenous lipid and protein become the major source of oxidative energy substrate • As sepsis progresses, reduced splanchic blood flow and severe hepatic dysfunction eventually lead to hypoglycemia and decreased glucose production

  16. Metabolic Response During Sepsis Protein Metabolism • Amino acids released from skeletal muscle breakdown, connective tissue, and unstimulated gut are shunted to the liver, where they are used in gluconeogenesis and for the synthesis of acute-phase reactants • The ureagenesis rate is increased, as well as the synthesis rates of creatinine, uric acid, and ammonia – all get excreted in the urine • In an unfed, stressed patient, up to 250 g of lean body mass will be broken down each day • The nitrogen loss of severe sepsis complicating recovery from trauma may exceed 30g/d • Adequate nutrition support will not completely ablate the catabolic effects and response

  17. Greenfield 1997

  18. Metabolic Response During Sepsis Lipid Metabolism • Lipolysisundercatecholamineregulation • Inearlysepsis,catabolichormonesoutweightheeffectsofanabolichormonessuchasinsulinandresultinthebreakdownofstoredtriglyceridestoglycerolandfreefattyacidsaffectingintracellulartransportmetabolism • Sepsisimpairsketogenesisandtheactivityoflipoproteinlipaseissuppressed • Hyperlipidemia,hyperglycemia,hyperlactatemia,andhighlevelsofcirculatingβ-hydroxybutyrateoftenarepresentinseveresepsis

  19. Metabolic Needs - How Much? • Assessment of metabolic rate is an integral part of the nutrition care of the ICU patient • Validity of multiple equations in this population has not been systematically evaluated • Metabolic rate can be gauged by 3 methods: • Indirect calorimetry (“gold standard”) • Pulmonary artery catheter measurements using the Fick equation VO²=cardiac output X 10 (CaO²-CvO²) where VO² is oxygen consumption in mL/min, cardiac output is in L/min, CaO² is concentration of oxygen in arterial blood (mL/dL), and CvO² is concentration of oxygen in mixed venous blood (mL/dL) • Can be estimated using several predictive equations based on body size, degree of injury/illness, or degree of inflammatory response • Given the limitations on the availability of indirect calorimetery, predictive equations are the mainstay of energy expenditure assessment in the ICU

  20. Ideal Body Weight (IBW) The Hamwi Method • Adult females • 100 lb (45kg) for the first 60 inches (152 cm) + 5 lbs (2.3 kg) for every inch > 60 • Ex: Ht. 5’4” (165.1 cm) = IBW of 120 lb or 54.5 kg) • Adult males • 106 lb (48 kg) for the first 60 inches (152 cm) = 6 lbs (2.7 kg for every inch > 60 • Ex: Ht. 5’10” (180.3 cm) = IBW of 166 lb or 75.4 kg)

  21. Evaluation of Body Weight Data • Body Mass Index (BMI) - a weight-stature index, is use both as a measure of obesity and malnutrition. • BMI = Weight (kg) ÷ Height² (m²) • Interpretation of BMI: • 18.5 – 25 Normal weight • 25-29.9 Overweight • 30-34.9 Obesity grade I • 35-39.9 Obesity II • ≥40 Obesity grade III • 17-18.4 Protein-energy malnutrition grade I • 16-16.9 Protein-energy malnutrition grade II • <16 Protein-energy malnutrition grade III • Individual variation is large so patients should not be misclassified as undernourished or obese using BMI alone

  22. Goal Calculations - Harris-Benedict Equation • Estimates Basal Energy Expenditure (BEE): • Male BEE = 66 + (13.7 x Wt) + (5 x Ht) - (6.8 x age) • Female BEE = 665 + (9.6 x Wt) + (1.8 x Ht) - (4.7 x age) • Weight (Wt) in kilograms; Height (Ht) in centimeters • BEE X Stress Factor (see below); this prediction method can overestimate or underestimate true resting metabolic rate and may be too unreliable for clinical use in the ICU

  23. Goal Calculations – Ireton-Jones Equation 1992 vs 1997 Version • Developed for intubated patients • RMR=(W x 5) – (A x 10) + (S x 281) + (T x 292) + (B x 851) +1925 for total calorie prescription where: • A=age • W=wt in kg • S=sex (1=male, 0=female) • T=trauma (1=yes, 0=no) • B=burns (1= yes, 0 = no) • (This is the 1992 version) • The corrected 1997 version of this equation does not perform as well as the 1992 version and is not recommended for use

  24. Goal Calculations – Critically Obese • Permissive underfeeding or hypocaloric feeding is recommended • CALORIES: When BMI is >30 provide 11-14 kcal/kg ACTUAL body weight/day or 22-25 kcal/kg ideal body weight per day • PROTEIN: When BMI is ≥ 30-40, provide ≥2.0 g/kg/ideal body weight per day and if BMI is ≥40, provide ≥2.5 g/kg ideal body weight per day • Choban PS. Nutr Clin Pract. 2005;20:480-487.

  25. Nitrogen Balance • Used to reflect the balance between exogenous nitrogen intake and renal removal of nitrogen-containing compounds through stool, urine, skin, fistulas, wounds, etc. • Measurement of nitrogen balance is most accurate in patient who receive a defined nutrient intake such as is in the case in those receiving enteral or parenteral nutrition • Urea nitrogen urine concentration increases dramatically in the sickest of patients reflecting catabolism of protein associated with systemic inflammation

  26. Greenfield 1997

  27. Calculating Nitrogen Balance • UUN excretion may differ from 3 to 5 grams

  28. Problems With UUN • UUN will be invalid if creatinine clearance is <50 mL/min • One cannot assume that moving nitrogen in a positive direction always means that protein catabolism has decreased, particularly in inflammatory (disease and trauma) conditions • Valid 24-hour urine collections are difficult to obtain • Alterations in renal function frequently occur in patient with inflammatory metabolism, making standard nitrogen balance calculations inaccurate

  29. Metabolic Cart / Indirect Calorimetry • Measurement of O2 consumption (VO2) and CO2 production (VCO2) by a metabolic cart to allow for a Measured Resting Energy Expenditure (MREE) and Respiratory Quotient (RQ) (VCO2/VO2) • RQ or respiratory quotient interpretation • 0.6-0.7 starvation/underfeeding • 0.84-0.86 desired range/mixed fuel utilization • 0.9-1.0 carbohydrate metabolism • 1.0+ overfeeding / lipogenesis

  30. Clinical Indications for Indirect Calorimetry • Factors causing predictive equations to be inaccurate (ARDS, large open wounds or burns, MSOF, sepsis, SIRS, ascites, multiple trauma, use of paralytic or barbiturate agents, and malnutrition with altered body composition like obesity or limb amputations) • When patients fail to respond to nutrition support based on predictive equations during their clinical course (poor wound healing, failure to wean from vent and protein malnutrition) despite “adequate” support • To evaluate whether under- or overfeeding is contributing to metabolic and respiratory derangements in ICU patients

  31. Technical Factors Decreasing Indirect Calorimetry Accuracy • Mechanical ventilation with FIO² ≥ 60 • Mechanical ventilation with Positive End Expiratory Pressure (PEEP) >12 cm H2O • Leak in the sampling system • Moisture in the system can affect the oxygen analyzer • Inability to collect all expired gases (leaking CT’s or broncho-pleural fistula) • Supplemental O2 in spontaneously breathing patient • Dialysis or continuous renal replacement therapy in progress • Errors in calibration of indirect calorimeter • Wooley JA. Nutr Clin Pract. 2003;18:434-439.

  32. Enteral vs. Parenteral? • Several studies have compared each mode of therapy • Traditionally it’s been said: “Enteral is BETTER” and “If the gut works, use it” • Earlier studies did not adjust for “overfeeding” and various rates of hyperglycemia increasing infectious complications • Earlier meta-analyses failed to show benefit of TPN over EN • PN use safer today with NST availability and tighter glucose control decreasing overall infectious complications • Bistrian BR. Crit Care Med 2006;34:1525-1531

  33. Enteral vs. Parenteral? • Use the GI tract whenever possible • Contraindications to GI feeds • Bowel obstruction / prolonged ileus > 7 day • High output fistula > 500 mL/d • Bowel ischemia • Intractable vomiting or diarrhea • Severe GI bleeding • Conditions precluding feeding tube placement (i.e. esophageal tumor or tear) • Acute exacerbation of IBD with PO intolerance (malnutrition + bowel rest > 7 days) • Failure of high risk, hypermetabolic patient to tolerate TF trials

  34. ICU Enternal Feeding Algorithm

  35. Nutrition Support Protocol For Mechanically Vented Patients • Developed by multidisciplinary team approach • Timing of enteral nutrition • Identify high risk patients • Identify malnourished patients • Progression to minimal enteral nutrition goals (80%) • Monitor gastric residuals • Use of prokinetic agents or surgically placed jejeunal tubes with gastric intolerance • Mackensiz SL. JPEN 2005;29(2):74-80

  36. Results of Nutrition Support Protocol in Mechanically Vented Patients • Percentage of patients receiving 80% of nutritional goals rose from 20% to 60% (p<0.001) • Goal achieved in just 5 days • TPN use declined from 13% to 1.6% (p<0.02) • Significant increase in delivered calories • No data on the effect on outcome • Mackensiz SL. JPEN 2005;29(2):74-80

  37. Early Nutritional Support in the Mechanically Vented Patient • 4,049 ventilated (>2 days) patients were studied • 2,537 (63%) labeled “Early Feeding” (<48 hours) • 1,512 (37%) labeled “Late Feeding Group” • Patients with contraindication to enteral diet were excluded • Control for disease severity using separate models with: • APACHE II, SAPS II, MPM-0 • Retrospective multi-institutional study Artinian V, et al; Chest 2006;129(4):960-967

  38. Artinian V, et al; Chest 2006;129(4):960-967 Effect of Early Feeding in Ventilated Patients

  39. Timing of Enteral Feeds • Many studies claim benefits to early EN • Meta-analysis that looked at 27 randomized, prospective studies • Early EN had lower infections (RR 0.45) • Early EN had shorter LOS (2.2 days) Marik PE, Zaloga GP. Crit Care Med. 2001;29:2264-2270

  40. How Nutrition Support Goals Have Shifted in the ICU Goals have become more focused on “nutrition therapy” • Attempt to attenuate the metabolic response to stress • Prevent oxidative cellular injury • Modulate the immune response Aim for early enteral nutrition, appropriate macronutrient and micronutrient delivery and meticulous glycemic control

  41. Where to start?! • Determine number of calories needed • Use predetermined “feeding weight” whether actual, ideal, adjusted or usual body weight first • Utilize predictive equations, indirect calorimetry • Determine normal or increased protein needs • Severity of injury, presence of wounds, fistulas, burns • Determine if contraindication to fats • Sepsis, hemodynamic instability, hypertriglyceridemia • Determine fluid needs • Determine mode of nutrition => use the GI tract whenever feasible

  42. ICU Nutrition Guidelines Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine and American Society for Parenteral and Enteral Nutrition: Executive Summary Robert G. Martindale, MD, PhD; Stephen A. McClave, MD; Vincent W. Vanek, MD; Mary McCarthy, RN, PhD;Pamela Roberts, MD; Beth Taylor, RD; Juan B. Ochoa, MD; Lena Napolitano, MD; GailCresci, RD; American College of Critical Care Medicine; and the A.S.P.E.N. Board of Directors Crit Care Med 2009;37(5):1757-1761 JPEN 2009;33(3):277-316 Guidelines developed that provided recommendations supported by review and analysis of the pertinent available current literature up to May 2008, by other national and international guidelines, and by the blend of expert opinion and clinical practicality. A grading system was used to help determine the level of evidence to support these recommendations.

  43. Grading System Used for the Guidelines • Grade of recommendation • A. Supported by at least two level I investigations • B. Supported by one level I investigation • C. Supported by level II investigations only • D. Supported by at least two level III investigations • E. Supported by level IV or level V evidence • Level of evidence • Large, randomized trials with clear-cut results; low risk of false-positive (alpha) error or false-negative (beta) error • Small, randomized trials with uncertain results; moderate to high risk of false-positive (alpha) and/or false-negative (beta) error

  44. Grading System Used for the Guidelines • Nonrandomized, contemporaneous controls • Nonrandomized, historical controls • Case series, uncontrolled studies, and expert opinion • Large studies warranting level I evidence were defined as those with 100 patients or those which fulfilled end • point criteria predetermined by power analysis. Meta-analyses were used to organize information and to draw • conclusions about overall treatment effect from multiple studies on a particular subject. The grade of • recommendation, however, was based on the level of evidence of the individual studies. Dellinger RP. Crit Care Med. 2004;32(11)(suppl):S446

  45. “Guidelines”: Enteral Feeding • Enteral Nutrition (EN) is the preferred route of feeding over parenteral nutrition (PN) (Grade B) • EN should be started early within the first 24-48 hours following admission (Grade C) and feedings should be advanced toward goal over the next 48-72 hours (Grade E) • EN should be withheld until the patient is fully resuscitated and/or hemodynamically stable (Grade E) • Neither presence nor absence of bowel sounds, flatus, and stool is required for the initiation of EN (Grade B) • Either gastric or small bowel feeding is acceptable (Grade C)

  46. “Guidelines”: When to Use Parenteral Nutrition • If early EN is not feasible or available over the first 7 days following admission to the ICU, no nutrition support (standard therapy) should be provided (Grade C) • If there is evidence of protein-calorie malnutrition at admission and EN is not feasible, it is appropriate to initiate PN as soon as possible following admission and adequate resuscitation (Grade C) • If a patient is expected to undergo major upper GI surgery and EN is not feasible, provide PN when: • Patient is malnourished. Initiate PN 5-7 days preoperatively and continue into the postoperative period (Grade B) • The duration of therapy is anticipated to be ≥ 7 days (Grade B)

  47. “Guidelines”: Dosing of Enteral Feeding • The target goal of EN (defined by energy requirements) should be determined and clearly identified at the time of initiation of nutrition support therapy (Grade C) • Efforts to provide > 50%-65% of goal calories should be made to achieve the clinical benefit of EN over the first week of hospitalization (Grade C) • Initiating supplemental PN before 7-10 days when unable to meet energy requirements with EN alone does not improve outcome and may be detrimental to the patient (Grade C) • In patients with BMI <30, protein requirements should be in the range of 1.2-2.0 g/kg/d actual body weight (Grade E) • Critically ill obese patients with BMI >30, give 11-14 kcal/kg actual body weight/day or 22-25 kcal/kg IBW/d. Protein should be provided in a range of ≥2.0 g/kg IBW/d for BMI 30-40 and ≥2.5 g/kg IBW/d for BMI ≥40 (Grade D)

  48. “Guidelines”: Selection of Appropriate Enteral Formula • Immune-modulating formulations containing arginine, glutamine, nucleic acid, omega-3 fatty acids and antioxidants should be used for major elective surgery, trauma, burns, head and neck cancer, and critically ill patients on vents. Be cautious with severe sepsis for SICU patients (Grade A) and MICU patients (Grade B). • Patients with ARDS and severe acute lung injury should receive a formula containing an anti-inflammatory lipid profile containing omega-3 fish oils, borage oil and antioxidants (Grade A)

  49. What is Immunonutrition (IMN)? • The term given to describe special enteral feeds containing: • Arginine • Omega-3 fatty acids • Nucleotides • + / - Glutamine • Antioxidants

  50. Organs of the Immune System

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