Applied Nutrition in ICU Patients*. A Consensus Statement of the American College of Chest Physicians. Frank B. Cerra, MD, FCCP; Marta Rios Benitez, MD;.
accp consensus statement Applied Nutrition in ICU Patients* A Consensus Statement of the American College of Chest Physicians Frank B. Cerra, MD, FCCP; Marta Rios Benitez, MD; George L. Blackburn, MD, PhD; Richard S. Irwin, MD, FCCP; Khursheed Jeejeebhoy, MD; David P. Katz, PhD; Susan K. Pingleton, MD, FCCP; James Pomposelli, MD, PhD; John L. Rombeau, MD; Eva Shronts, MMSc, RD, CNSD; Robert R. Wolfe, PhD; and Gary Paul Zaloga, MD, FCCP
(CHEST 1997; 111:769-78) Abbreviations: BCAA5branched chain amino acids; EN5enteral nutrition; IBW5ideal body weight; PUFA5polyunsaturated fatty acids; R/Q5respiratory quotient
Outline of Consensus Statement on Nutrition I. Introduction to the consensus statement II. The consensus statement A. Malnutrition in critically ill patients B. General goals and principles 1. General goals of nutrition support 2. General principles of nutrition support C. Specific considerations 1. The systemic inflammatory response syndrome (SIRS), with or without multiple organ dysfunction syndrome (MODS) 2. Renal failure 3. Liver failure 4. Non-ARDS respiratory failure 5. Obesity 6. Preexisting malnutrition 7. Diabetes mellitus 8. Immunodeficiency states 9. Geriatric patients 10. Lymph fistulas *Developed for ACCP Health and Science Policy Committee by the Nutrition Consensus Group. A complete list of the Consensus Group is located in Appendix 1. Manuscript received November 27, 1996; accepted December 2. Reprints of this Consensus Statement are available from the American College of Chest Physicians. To order, phone 1-800343-ACCP or 1-847-498-1400.
D. New developments: foods for special dietary purposes 1. Glutamine 2. Branched chain amino acids 3. Peptides in enteral formulations 4. Growth hormone 5. Arginine 6. Omega-3 polyunsaturated fatty acids (fish oils) 7. Nucleic acids 8. Nutrient combinations for modulation of immune function 9. Glycerol 10. Nutrients with antioxidant properties 11. Short-chain fatty acids 12. Fiber Introduction to the Consensus Statement Nutrition support is a routine part of ICU therapy. It is recommended to treat and prevent malnutrition and nutrient deficiencies and generally benefits patient outcomes, although adverse effects and complications of the therapy do occur. Because a large number of clinical studies of applied nutrition have been performed in ICU patients, a consensus panel was commissioned to summarize current knowledge and formulate recommendations. The goals of the consensus process were to (1) define the clinical ICU settings where nutritional therapy benefits patient outcomes, (2) define the goals of nutrition therapy, and (3) identify the nutrient needs of ICU patients. The objectives of the process were to develop general guidelines for patient selection, timing and route of administration, nutrient use, and monitoring of the therapy. CliniCHEST / 111 / 3 / MARCH, 1997
769
cally relevant outcomes for nutrition therapy were evaluated and areas of current research that may have future clinical relevance were identified. Three constraints were imposed on the consensus process: (1) to consider only adult patients, (2) to consider only patients whose acute disease was of sufficient magnitude to warrant admission and treatment in an ICU; and (3) to consider clinical settings requiring at least 4 days of ICU confinement. Generally, these patients require life support and are receiving mechanical ventilation; they also constitute the greatest mortality risk and the most intense use of ICU resources.1 Three information sources were used by the consensus participants: (1) an assessment of the peerreviewed literature, with priority given to randomized, prospective clinical studies, then to retrospective clinical studies; (2) a compilation of the generally accepted knowledge in the field of nutrition; and (3) the experience of knowledgeable practitioners of nutrition therapy in ICU patients. Research will continue in this area of therapy and updates to this consensus statement will be needed. This statement may be used as a resource for establishing guidelines for nutrition support and as a resource for quality management functions for institutions or individual practice settings.
The Consensus Statement Malnutrition in Critically Ill Patients Malnutrition is a disorder of body composition in which macronutrient and/or micronutrient deficiencies occur when nutrient intake is less than required, and which results in reduced organ function, abnormal results of blood chemistry studies, reduced body mass, and less optimal clinical outcomes. It is a common problem in critically ill patients that can be present upon admission to the ICU or can develop during the course of critical illness. Various disease processes common to the ICU patient result in changes in substrate metabolism that also lead to clinical manifestations of altered body composition and nutrient deficiencies.2 In malnutrition due to simple starvation or undernutrition, fat and protein are lost, but the loss of protein is minimized by reducing the need to use it as a source of energy (Appendix 2). Nitrogen loss is modified by mobilization of fat, and enhanced fat oxidation becomes a principal source of energy in the starving individual. Some protein wasting does occur despite the availability of fat, and it becomes markedly accelerated when fat stores are depleted. In critical illness with hypermetabolism, as in sepsis, accelerated protein catabolism occurs to provide energy and to support 770
Figure 1. The response to tissue injury manifests as shock, resuscitation, the systemic inflammatory response, and organ dysfunction and progressive organ failure. The physiologic and metabolic responses are regulated by neural, hormone, paracrine, and autocrine mediator response mechanisms. Reprinted with permission from Cerra FB. Dis Month 1992; 38:843-947.
increased protein synthesis (Fig 1). With inadequate caloric intake, energy sources are derived from excessive protein breakdown and gluconeogenesis. Various protein “pools” can be depleted to provide fuel and metabolic substrate, including muscle and visceral protein. Thus, assessment of malnutrition in critically ill patients includes evaluation of clinical, anthropometric, chemical, and immunologic parameters reflecting altered body composition.3 It is important to note that currently there is no one readily available test that is both sensitive and specific for malnutrition in critically ill patients. All tests suffer from significant limitations and any application has to be considered in the light of those limitations. Loss of body weight, which is universally coincident with protein caloric malnutrition, provides a readily accessible indication of altered nutritional status. Weight loss in excess of 10% ideal body weight (IBW) suggest malnutrition.4 Unfortunately, many critically ill patients are edematous and the measured weight may not reflect the real body cell mass. Hepatic secretory proteins such as albumin, transferrin, retinol binding protein, and prealbumin are markers of visceral protein stores and are used as indicators of nutritional status. As these proteins have various half-lives, eg, albumin (t1⁄2518 days) and transferrin (t1⁄258 days), they have variable sensitivity as predictors of nutritional status. Hepatic protein production, however, is influenced by numerous factors in addition to the nutritional status, Consensus Statement
including disorders of hepatic function, protein losing states, and acute infection or inflammation. The frequent presence of these conditions in ICU patients limits the effectiveness of these proteins as markers of nutritional deficiency or the effectiveness of nutrition support. Anthropometry involves measurement of skin folds, circumferences, and skeletal breadths to divide the body into compartments of fat, muscle tissue, and skeletal mass. The primary advantages of anthropometrics over more complex body composition measurements include simplicity, safety, cost, and widespread application. However, while techniques of measurement are standardized, interpretation of results remains controversial and of limited value in the acute ICU setting. Creatinine height index is a theoretic estimate of lean body mass derived from measurement of the 24-h urinary creatinine excretion compared with standard values for a given height. Factors that influence creatinine excretion, therefore, complicate the interpretation of this index and include age, diet, exercise, stress, and renal disease. Cellular immunity or delayed cutaneous hypersensitivity is commonly tested by recall to skin-test antigens such as Candida, mumps, Trichophyton, and streptokinase-streptodornase. Depression of cellular immunity has been consistently associated with malnutrition and nutritional repletion is associated with improved immunocompetence. In ICU patients, the utility of skin testing is limited by a number of disease states and drugs associated with anergy, such as infection, malignancy, radiotherapy, chemotherapy, burns, other immunocompromising diseases, and the use of steroids and antirejection medications. Technical application and interpretation of skin tests in an ICU population remain difficult. Multiparameter nutritional indexes have been proposed to overcome the sensitivity and specificity difficulties of single nutritional assessment tests. The prognostic nutritional index is a mathematical formulation combining measurements of serum albumin, triceps skinfold thickness, transferrin, and delayed hypersensitivity skin testing.5 Although the prognostic nutritional index can be a predictor of major morbidity in surgical patients, its utility in the ICU and in medical patients is less well evaluated. Muscle function tests have been used as a marker of nutritional status. Clinical investigations have focused on assessment of adductor pollicus muscle, handgrip dynamometry, and respiratory muscle strength.6 Changes in twitch characteristics of the adductor pollicus muscle occur with stimulation of the ulnar nerve in malnourished patients. The lack of technical expertise and equipment limits widespread
clinical application. Handgrip dynamometry can predict postoperative complications. Respiratory muscle strength as assessed by maximal airway or transdiaphragmatic pressures, endurance as assessed by maximal voluntary ventilation, and vital capacity measurements are reduced in malnourished patients.7 Limitations of these techniques in ICU patients are multiple and include, in the case of maximal voluntary ventilation and vital capacity, the need for an awake, alert patient. Metabolic factors such as hypercapnia, hypoxia, medications, and intrinsic muscle disease also complicate interpretation. Newer more sophisticated methods of nutritional assessment being evaluated include nuclear magnetic resonance, whole body conductance and impedance, and neutron activation. Little data exist evaluating their utility in ICU patients. In conclusion, multiple tests and combinations of tests are available to assess nutritional status. No simple recommendation can be given regarding the “best” test for nutritional assessment. Use of any of these methods can be appropriate, providing the limitations are clearly understood. Although not studied in ICU patients, it is important to note that data in hospitalized patients suggest that clinical assessment of nutritional status, including weight loss (.10% IBW), is as reliable an indicator of malnutrition as more complex tests of nutritional assessment.8 General Goals and Principles General Goals of Nutrition Support: This portion of the consensus document summarizes the general goals of nutrition support in ICU patients: (1) provide nutritional support consistent with the patient’s medical condition, nutritional status, and available route of nutrient administration; (2) prevent or treat macronutrient and micronutrient deficiencies; (3) provide doses of nutrients compatible with existing metabolism; (4) avoid complications related to the technique of dietary delivery; and (5) improve patient outcomes such as those related to disease morbidity, eg, body composition, tissue repair, and organ function, and those affecting resource utilization, medical morbidities and mortalities, and subsequent patient performance. General Principles of Nutrition Support: This portion of the consensus document summarizes the general nutrient requirements and principles of providing nutrition support in ICU patients. These general considerations may need to be modified in accord with the disease(s) present; modifications are presented in the section entitled “Specific Considerations.” CHEST / 111 / 3 / MARCH, 1997
771
Macronutrients (1) Total Calories: The existing body cell mass is a major determinant of the total caloric requirement. The total caloric requirement can either be estimated or directly measured. Whether precisely matching energy input with energy expenditure improves patient outcomes remains controversial. Calorie overload should be avoided, but energy should be administered to promote anabolic functions. Administering 25 total kilocalories per kilogram usual body weight per day (1 kg/d) appears to be adequate for most patients. The total calories should be administered in a volume consistent with the total fluid needs of the patient. In general, 1 mL of water is needed per kilocalorie administered. (2) Glucose: 30 to 70% of the total calories administered per day can be given as glucose, ie, up to 2 to 5 g glucose per kilogram per day. The dose should be adjusted to maintain a blood glucose level ,225 mg/dL, including administering regular insulin, if necessary. (3) Fats: 15 to 30% of the total calories administered per day can be provided as fat. Omega-6 polyunsaturated fatty acid (PUFA) triglycerides should be provided in doses adequate to prevent essential fatty acid deficiency, ie, at least 7.0% of total calories. Medium-chain triglycerides can be used as a source of calories. The ratio of mediumchain triglycerides to long-chain triglycerides administered is dependent on the route of administration and on product availability. (4) Protein Sources: 15 to 20% of the total calories administered per day can be given as protein or amino acids. The calorie-to-nitrogen ratio of the formulation is not a useful consideration in choosing protein sources. Initiation of therapy can be estimated at 1.2 to 1.5 g/kg/d and adjusted with periodic monitoring to promote nitrogen retention and support protein synthetic functions. Considerations for a decrease in dosing include a rising BUN level that exceeds 100 mg/dL, and a rising blood ammonia level that is associated with clinical encephalopathy. Micronutrients The precise requirements for vitamins, minerals, and trace elements have yet to be determined. Potassium, magnesium, zinc, and phosphate should be provided in doses adequate to maintain normal serum levels. Normal serum levels will vary with the laboratory in which the measurement is performed. Useful information on micronutrient administration is presented in the material on micronutrients in the “Background and Supporting Information” section of this document. Normal values are summarized in Table 1. Route of Administration (1) The Enteral Route: The enteral route is pre772
Table 1—Normal Values of Serum and Blood Vitamin Levels Vitamin
Units
Normal Deficient
Retinol 25-Hydroxy D 1,25-Dihydroxy D a-Tocopherol Blood thiamine Urine thiamine Blood riboflavin Urine riboflavin Plasma vitamin B6 Urine vitamin B6 Serum niacin Urinary N1-methylnicotinamide Ascorbic acid Plasma biotin Urinary biotin Carotenoids Vitamin B12 Folic acid
mg/dL mg/dL ng/dL mg/dL mg/dL mg/g creatinine mg/dL mg/g creatinine mg/dL mg/g creatinine mg/dL mg/d mg/dL ng/dL mg/d mg/dL pg/mL ng/mL
10–100 ,10 0.8–5.5 ,0.7 2.6–6.5 7.0–20.0 ,5 2.5–7.5 ,1.7 .66 ,27 10–50 ,10 .79 ,27 .5.0 ,2.5 .20 ,20 300–600 ,300 2.2–9.4 ,0.5 0.4–1.5 ,0.3 30–74 6–50 ,6 80–400 205–867 ,140 3.3–20 ,2.5
ferred for nutrient administration. Use of the enteral route is associated in clinical studies with preservation of gut integrity, barrier and immune functions, and reductions in infectious complications. Current data support the initiation of enteral nutrition (EN) as soon as possible after resuscitation. Intragastric feeding requires adequate gastric motility. In general, a gastric residual of .150 mL will require a moderation of the infusion rate, consideration of supplemental IV nutrition, or the use of small bowel feedings. Small bowel feedings can usually be performed, even in the presence of gastric atony and colonic ileus. Concomitant gastric decompression may be required. The role of agents designed to improve gastric and intestinal motility is not yet established, eg, cisapride, erythromycin. The presence of bowel sounds and the passage of flatus or stool are not necessary for the initiation of enteral feedings, particularly when feedings are administered distal to the pylorus. Increasing abdominal distention necessitates cessation of the feedings and a medical evaluation. Small bowel feedings, in general, are efficacious in the presence of mild or resolving pancreatitis and low output enterocutaneous fistulas (,500 mL/d) and can be administered until clinical intolerance occurs. Diarrhea may occur with the administration of enteral feedings. It is usually secretory and is generally not an indication to discontinue enteral feedings. If it exceeds 1,000 mL/d, an evaluation is required. If a relevant medical or surgical cause is not found, including Clostridium difficile enterocolitis, antidiarrheal agents may be used. (2)The Parenteral Route: The parenteral route of Consensus Statement
nutrient administration is recommended when the enteral route is not accessible or usable, or as a supplement to enteral feeding if adequate nutrient administration is not possible via the enteral route alone. The use of the parenteral route is associated with an increased incidence of infectious complications, including the line access used for administration, and a significant incremental cost. Parenteral formulations are not as nutritionally complete as enteral formulations. However, the achievement of nutritional goals is more often attained by the parenteral route. Strict adherence to administration protocols can reduce the complication rate. This is particularly so for central line care. Central lines for feeding must be placed and cared for with strict aseptic technique and used with limited interruption. Implanted, permanent lines are not recommended in the acute ICU setting. Consideration should be given to the use of peripheral indwelling central catheters lines. Monitoring: Monitoring is essential to minimize complications and maximize the benefits of nutrition support. (1) Avoid overfeeding. (a) Adhere to the general guidelines as presented. (b) Although generally not necessary if the general guidelines of nutritional support are followed, expired gas analysis may be useful in this assessment; a respiratory quotient (R/Q) .1 generally indicates overfeeding; increased CO2 production is present in R/Qs that increase from the 0.80 to 1.0 range. (c) A reduction of total calorie (glucose and fat) loads to decrease carbon dioxide production may be beneficial in parenterally fed patients with respiratory compromise. (2) Promote nitrogen retention and avoid protein overload. (a) The periodic assessment of nitrogen balance can be useful in adjusting the dose of protein (amino acids). Measurements every 5 to 7 days are useful for this purpose. (b) Excessive prerenal azotemia from protein (amino acid) administration is an indication to decrease nitrogen intake. BUN levels in the #100 mg/dL range are generally well tolerated. (c) Special formulations for acute renal failure (serum creatinine concentration elevated to twice normal range) do not benefit patient outcomes. (d) Consideration should be given to using dialytic (dialysis or the various forms of continuous hemofiltration) therapy to meet the goals of nutrition support in patients with renal failure. (3) Monitoring triglyceride clearance is recommended.
(a) Precise definitions of excessive levels of plasma triglycerides are difficult; a triglyceride level of #500 mg/dL with continuous fat infusion is accepted by some critical care physicians. (4) Weekly monitoring of visceral protein levels in plasma may be useful, eg, transferrin or prealbumin. However, in ICU settings, their levels may not be indicative of the response to feeding and do not appear to correlate well with patient outcomes. The measurement of serum albumin level is generally not useful in the assessment of the response to nutrition support in these acute settings. (5) Adequate monitoring of fluid and electrolyte status is necessary, particularly for potassium, phosphate, magnesium, calcium, and zinc. Serum levels well within the normal range should be maintained. (6) Vitamin and trace element levels. (a) Routine monitoring is probably not useful. (b) Monitoring on a selected case basis where deficiency states are clinically suspected is encouraged. (7) Weekly assessment of liver function with standard laboratory tests should be performed. Abnormalities in the results of standard tests of liver function are generally not an indication for liver specific nutrition (ie, use of modified amino acid formulas designed for liver failure). Specific Considerations This portion of the consensus document summarizes alterations of the general principles that result from the disease(s) that may be present in ICU patients. More than one disease is frequently present in an individual patient. Practitioners should start with the general principles of nutrition support and then modify the nutrients administered as necessary for the disease(s) that are present. Whenever a question arises, consultation with a nutrition practitioner or your nutrition support service is advised. The Systemic Inflammatory Response Syndrome, With or Without Multiple Organ Dysfunction Syndrome: The metabolism in systemic inflammatory response syndrome is characterized by increased total caloric requirements, hyperglycemia, triglyceride intolerance, increased net protein catabolism, and increased macronutrient and micronutrient requirements. Caloric requirements may need to be increased 10 to 20%. Hyperglycemia, even in the absence of diabetes mellitus, is frequently present. When the blood glucose level exceeds 225 mg/dL, glucose loads must be reduced and/or regular insulin administration begun to maintain a blood glucose level under 225 mg/dL. The increased net protein catabolism necessitates an increase in protein adminCHEST / 111 / 3 / MARCH, 1997
773
istration. In general, nitrogen retention is promoted with 1.5 to 2.0 g/kg/d of protein (amino acids), not to exceed 2.2 g/kg/d. Hypertriglyceridemia with lipemic serum may occur. If serum lipemia is not present, the general principles for fat administration can be used. If serum lipemia is present and the serum triglyceride level exceeds 500 mg/dL, total calories and/or the dose of omega-6 PUFA triglyceride should be reduced. The fat dose can be reduced by one third and the glucose load can be reduced to as low as 100 g/d. If the lipemia persists, the duration of the fat infusion can be increased up to 24 h per dose and/or heparin sodium (1 U/mL) can be given with the infusion. Once the triglyceride intolerance has abated, the doses of glucose and fat can be increased and the presence of lipemia reassessed. Requirements for micronutrients are also increased. In addition, there may be excessive losses of potassium, zinc, magnesium, calcium, and phosphorus. Serum levels need to be more closely monitored and maintained within the normal range. Renal Failure: Renal failure is accompanied by intolerance to fluids (oliguric/anuric form) and a rise in the plasma levels of potassium, magnesium, and phosphate. Frequent monitoring of these analytes is needed and the amounts administered reduced to maintain appropriate plasma levels. Diuretics are very useful in maintaining these balances; dialytic therapy may also be necessary to achieve appropriate nutritional support. As opposed to chronic renal failure, there is no need to alter the amount of protein (amino acid) administered to patients with acute renal insufficiency. There is also no demonstrable advantage to alter the composition of the protein (amino acid) administered, eg, by administering just essential amino acids. In patients with chronic renal insufficiency, protein (amino acid) dose of 0.5 to 0.8 g/kg/d is associated with preservation of renal function; and maintaining an arterial blood pH of .7.35 is associated with reduced net catabolism. The consequences of dialytic therapy also need to be considered. Peritoneal dialysis fluid contains glucose, the amount of which needs to be considered in the determination of glucose and total calorie dosing. Peritoneal dialysis also removes amino acids, frequently in the range of 40 to 60 g/d. Hemodialysis and hemofiltration remove amino acids in the range of 3 to 5 g/h. These losses need consideration when adjusting the protein (amino acids) administered. Liver Failure: Patients with liver failure as a single organ failure, eg, cirrhosis, may be hypermetabolic. This determination needs to be made. Most patients will have increased losses of potassium, magnesium, and zinc and may be treated with fluid restriction for 774
the presence of significant ascites. Close attention to fluid and electrolyte management is necessary. Encephalopathy frequently accompanies liver failure. Some protein should be provided during this time. The dose of protein is reduced to the 1.0 to 1.3 g/kg range. If encephalopathy worsens or does not improve, or nutritional requirements are not met, consideration should be given to the use of enteral or parenteral products specifically designed for isolated liver failure. Generally, these products have an increased content of the branched chain amino acids (BCAA) and a reduced amount of the aromatic and sulfur-containing amino acids. The use of these preparations in settings other than isolated liver failure, eg, multiple organ dysfunction syndrome in the absence of underlying cirrhosis, is not recommended. There is no consensus on the nutritional management of fulminant liver failure resulting from viral hepatitis or drugs. Non-ARDS Respiratory Failure: Most patients with isolated respiratory failure can be treated by applying the general principles for nutrition support. With current product formulations, the calorie-tonitrogen ratio is not a major consideration. The major problem derives from overfeeding, ie, an excess of total calories, either as carbohydrate or fat, or both. If overfeeding is believed to be a clinical problem, or if there is difficulty in weaning a patient from the ventilator, expired gas analysis with a determination of energy expenditure and the R/Q can be useful in management. An R/Q over 1 usually indicates overfeeding. Additionally, a higher R/Q indicates increased carbon dioxide production. An R/Q in the 0.85 to 0.90 range in these settings is reasonable. A carbon dioxide production of 3 to 5 mL/kg or more is believed to be excessive. The administration of protein (amino acids) also increases oxygen consumption demands. In ICU patients, it is difficult to predict this effect. Oxygen consumption demand may be increased 15 to 20%. In general, this increased demand for oxygen is well tolerated and usually not an indication for reducing protein (amino acid) intake. Some experimental work also indicates that the BCAA may stimulate the respiratory center and improve the function of the muscles of respiration. Obesity: The dilemma in obesity is in judging the energy and nutrient requirements. For purposes of this consensus document, obesity is defined as a body mass index over 25. Nutrient needs can be effectively based on the ideal weight for height. Preexisting Malnutrition: For this consensus document, significant preexisting malnutrition is defined as a body mass index under 16. When it is present, nutrition support should be initiated as soon as Consensus Statement
possible after admission to the ICU when nutrition support has become a major consideration in the therapy for the patient, eg, following resuscitation. Refeeding patients with this degree of malnutrition may be associated with a number of refeeding syndromes, including excessive salt and fluid retention and dysrhythmias. Close attention to fluid and electrolyte management and ECG monitoring is necessary in the early stages of refeeding. The initial estimates of nutrient requirements should be based on the existing body weight appropriately reduced for the estimated amount attributed to edema, ascites, and pleural effusions. After 7 to 10 days, nutrient requirements can be based on the IBW. Diabetes Mellitus: Diabetes mellitus is common in ICU patients. Management of blood glucose level is essential for effective nutrition support. Close adherence to the general principles of glucose administration and monitoring will result in the successful treatment of most patients. Consensus does not exist on the most appropriate route of insulin administration. Options for regular insulin administration include the following: sliding scale, placing insulin in the parenteral nutrition administration container, or the use of a separate insulin infusion. In all cases, the goal is to maintain blood glucose level under 225 mg/dL. Immunodeficiency States (a) AIDS At this time, close adherence to the general principles of nutrition support is recommended. (b) Bone Marrow Transplantation In addition to optimizing the general principles of nutrition management, a few studies have observed improved patient outcomes with the use of supplemental glutamine by the IV route. Doses in the range of 0.5 g/kg/d of glutamine have been used in these patients. (c) Surgery, Trauma, Sepsis In patients with systemic inflammatory response syndrome, who frequently have prolonged ICU stays, EN within 24 to 72 h of injury has been associated with significant reductions in infectious complications. Enteral formulas enhanced with such agents as fish oil, arginine, and uracil as ribonucleic acid have been associated with significant reductions in hospital length of stay and infectious complications. The dose of omega-6 PUFA triglycerides should be reduced, but not lower than that necessary to prevent essential fatty acid deficiency—ie, 7% of the total calories. Doses of 1 g/kg/d are well tolerated. Geriatric Patients: For this consensus document, geriatric patients are defined as those patients who are 80 years of age or older. They require close
attention to monitoring in their nutritional management; otherwise, the general principles of nutrition management can be applied. Lymph Fistulas: When chylothorax is present, the use of total parenteral nutrition with IV fat is recommended. Otherwise, the general principles of nutrition support apply. New Developments: Foods for Special Dietary Purposes In addition to the role of macronutrients and micronutrients in the general nutrition support of ICU patients, specific nutrients are being evaluated for their individual effects on specific metabolic functions. These effects are being evaluated with doses that exceed those used in the general nutritional therapy of ICU patients. These potential pharmaconutrients are provided in a setting of balanced nutritional support. Glutamine: Glutamine is an amino acid that participates in a variety of metabolic processes, including the following: ammonia and hydrogen ion excretion in the kidney; the immune response; purine and pyrimidine synthesis; and the synthesis of glutathione. During catabolic states, it is mobilized in increased amounts from peripheral tissues such as skeletal muscle. Whether administering glutamine in increased quantities in catabolic states improves patient outcomes remains to be determined. Up to 0.5 g/kg/d has been used in clinical settings. Branched Chain Amino Acids: The BCAA— leucine, isoleucine, and valine—are essential amino acids required for protein synthetic functions. Given in a balanced amino acid formulation at a dose of 0.5 to 1.2 g/kg/d of branched chain, they can improve nitrogen retention with reduced ureagenesis and increased protein synthetic functions relative to standard amino acid formulations. Their precise role in promoting improved patient outcomes remains to be defined. Peptides in Enteral Formulations: Providing protein as peptides in enteral formulas may enhance enteral protein absorption. Their role in improving patient outcomes remains to be defined. Growth Hormone: When growth hormone is administered, a variety of metabolic effects may be observed, including increased fat oxidation, an increased rate of protein synthesis, and improved immune responsiveness. Its effects on patient outcomes in adult ICU patients remain to be defined. Arginine: Arginine is an amino acid that participates in a variety of metabolic functions, including nitric oxide and urea synthesis, lymphocyte proliferation, and wound healing. Its dosing and its role in improving outcomes in ICU patients remain to be CHEST / 111 / 3 / MARCH, 1997
775
defined. Doses of up to 30 g/d have been used in adult postoperative patients. Omega-3 PUFA (Fish Oils): Omega-3 PUFA have no established requirement in ICU patients. They are under clinical investigation as immune modulating and anti-inflammatory agents. Doses of up to 3 to 5 g/d in oil (eg, menhaden oil, canola oil) have been used in critically ill patients and/or patients with sepsis. Nucleic Acids: A nutritional requirement for nucleic acids has not been established. A number of nutrient roles of nucleic acids are being investigated. These roles include proliferation of intestinal crypt cells, lymphocyte proliferation, and cellular DNA and RNA synthesis. Nutrient Combinations for Modulation of Immune Function: Combinations of nutrients with immune function activity—arginine, fish oil, and nucleic acids—are being evaluated as components of balanced EN in patients who are immune suppressed following trauma, infection, and other forms of tissue injury. Several clinical studies have observed improvements in in vitro tests of lymphocyte function, a reduction in postoperative complications such as organ failure and infection, and a reduction in hospital length of stay. Glycerol: Glycerol has been used as an alternative, noninsulinogenic carbohydrate source. It has been observed to have protein-sparing activity when given in combination with amino acids. This combination can be given by peripheral vein. Its role in improving outcomes in ICU patients remains to be defined. Nutrients With Antioxidant Properties: Nutrients with antioxidant properties include selenium, vitamins C and E, and beta-carotene. With the exception of beta-carotene, these are essential nutrients. Their antioxidant properties are being evaluated experimentally. In metabolic stress models, such effects as decreased pentane production have been observed. Their role in ICU patients remains to be clarified. Short-chain Fatty Acids: No specific requirement for short-chain fatty acids has been established. These endogenous products of fiber fermentation are important for colonocyte integrity and function. A beneficial effect has been observed when they are given via enema in patients with acute colitis and in the clinical setting of diversion colitis. Their role in ICU patients remains to be defined. Fiber: Fiber as a component of EN products may have beneficial effects of colonocyte function. Its role in the nutritional therapy of ICU patients remains to be defined.
Director, Critical Care and Clinical Nutrition University of Minnesota Minneapolis Marta Rios Benitez, MD Fellow in Nutrition University of Minnesota Minneapolis George L. Blackburn, MD, PhD Associate Professor of Surgery Harvard Medical School Boston Richard S. Irwin, MD, FCCP Professor of Medicine Director Pulmonary, Allergy, and Critical Care Medicine University of Massachusetts Medical School Worcester Khursheed Jeejeebhoy, MD Professor of Medicine University of Toronto Toronto, ON, Canada David P. Katz, PhD Asst Professor of Medicine Assoc Director of Research Montefiore Medical Center and Albert Einstein College of Medicine Bronx, NY Susan K. Pingleton, MD, FCCP Professor of Medicine Director, Division of Pulmonary and Critical Care Medicine University of Kansas Medical Center Kansas City James Pomposelli, MD, PhD Clinical Fellow in Surgery Harvard Medical School Boston John L. Rombeau, MD Associate Professor of Surgery Hospital of the University of Pennsylvania Philadelphia Eva Shronts, MMSc, RD, CNSD Associate Director, Nutrition Support Service University of Minnesota Minneapolis Robert R. Wolfe, PhD Professor of Surgery, Anesthesiology, and Biochemistry University of Texas Medical Branch and Chief, Metabolism Unit Shriners Burn Institute Galveston Gary Paul Zaloga, MD, FCCP Professor of Anesthesia and Medicine Bowman Gray School of Medicine Wake Forest University Winston-Salem, NC
Appendix 2: The Harris-Benedict Equation43
Appendix 1: The Nutrition Consensus Group
Women: BEE56551(9.63weight in kg)1(1.73height in cm) 2(4.73age in years)
Frank B. Cerra, MD, FCCP Professor of Surgery and Interim Chairman
Men: BEE5661(13.73weight in kg)1(53height in cm) 2(6.8 3age in years)
776
Consensus Statement
References 1 Zook CJ, Moore FD. High-cost users of medical care. N Engl J Med 1980; 302:996-1002 2 Long CL, Schaffel N, Geiger JW, et al. Metabolic response to injury and illness: estimation of energy and protein needs from indirect calorimetry and nitrogen balance. JPEN J Parenter Enteral Nutr 1979; 3:452-56 3 Donohoe M, Rogers RM. Nutritional assessment and support in chronic obstructive pulmonary disease. Clin Chest Med 1990; 11:487-504 4 Hill GL. Body composition research: implications for the practice of clinical nutrition. JPEN J Parenter Enteral Nutr 1992; 16:197-218 5 Buzby GP, Mullen JL, Matthews DC, et al. Prognostic nutritional index in gastrointestinal surgery. Am J Surg 1980; 139:160-67 6 Klidjian AM, Foster KJ, Kammerling RM, et al. Relation of anthropometric and dynamometric variables to serious postoperative complications. BMJ 1980; 281:899-901 7 Arora NS, Rochester DF. Respiratory muscle strength and maximal voluntary ventilation in undernourished patients. Am Rev Respir Dis 1982; 126:5-8 8 Baker JP, Detsky AS, Wesson DE, et al. Nutritional assessment: a comparison of clinical judgment and objective measurements. N Engl J Med 1982; 306:969-72
Selected Readings 1 Wolfe RR. Carbohydrate metabolism in the critically ill patient: implications for nutritional support. Crit Care Clin 1987; 3:11-24 2 Wolfe RR, Durkot MJ, Allsop JR, et al. Glucose metabolism in severely burned patients. Metabolism 1979; 28:1031-39 3 Jahoor F, Shangraw RE, Miyoshi H, et al. Role of insulin and glucose oxidation in mediating the protein catabolism of burns and sepsis. Am J Physiol 1989; 257:E323-31 4 Wolfe BM, Wolker BK, Shaul DB, et al. Effect of total parenteral nutrition on hepatic histology. Arch Surg 1988; 123:1084-90 5 Wolfe RR, Herndon DN, Jahoor F, et al. Effect of severe burn injury on substrate cycling by glucose and fatty acids. N Engl J Med 1987; 317:403-08 6 Askanazi J, Carpentier YA, Elwyn DH, et al. Influence of total parenteral nutrition on fuel utilization in injury and sepsis. Ann Surg 1980; 191:40-6 7 Needleman P, Turk J, Jakschik BA, et al. Arachidonic acid metabolism. Ann Rev Biochem 1986; 55:69-102 8 Thonnart N, Cuvelier B, Bracamonte M, et al. Metabolic utilization of LCT vs mixed MCT/LCT emulsion during IV infusion in man. Clin Nutrition 1984; 4(suppl):50-57 9 Dawes RFH, Royle GT, Dennison AR, et al. Metabolic studies of lipid emulsion containing medium-chain triglyceride in perioperative and total parenteral nutrition infusions. World J Surg 1986; 10:38-46 10 Katz DP, Schwartz S, Askanazi J. Therapeutic value of omega-3 fatty acids derived from fish oil: biochemical and cellular basis. Nutrition 1993; 9:113-18 11 Windsor JA, Hill GL. Weight loss and physiologic impairment: a basic indicator of surgical risk. Ann Surg 1988; 207:290-96 12 Cerra FB, Hirsch J, Mullen K, et al. The effect of stress level, amino acid formula, and nitrogen dose on nitrogen retention in traumatic and septic stress. Ann Surg 1987; 205:282-87 13 Schloerb PR, Amare M. Total parenteral nutrition with glutamine in bone marrow transplantation and other clinical
14
15 16 17 18 19 20 21 22 23 24
25 26 27 28 29
30 31 32 33 34 35
applications: a randomized, double-blind study. JPEN J Parenter Enteral Nutr 1993; 17:407-13 Barbul A, Lazarou SA, Efron DT, et al. Arginine enhances wound healing and lymphocyte immune responses in humans. Surgery 1990; 108:331-37 Wolman SL, Anderson GH, Marliss EB, et al. Zinc in total parenteral nutrition: requirements and metabolic effects. Gastroenterology 1979; 76:458-67 Finch CA, Huebers H. Perspectives in iron metabolism. N Engl J Med 1982; 306:1520-28 Oppenheimer SJ. Iron and infection: the clinical evidence. Acta Paediatr Scand Suppl 1989; 361:53-62 Berger MM, Cavadini C, Bart A, et al. Cutaneous copper and zinc losses in burns. Burns 1992; 18:373-80 Antila H, Salo M, Na¨nto¨ V, et al. Serum iron, zinc, copper, selenium, and bromide concentrations after coronary bypass operation. JPEN J Parenter Enteral Nutr 1990; 14:85-9 Lowry SF, Goodgame JT Jr, Maher MM, et al. Parenteral vitamin requirements during intravenous feeding. Am J Clin Nutr 1978; 31:2149-58 Barbul A. Arginine and immune function. Nutrition 1990; 6:53-8 International glutamine symposium. Glutamine metabolism in health and disease: basic science and clinical aspects. JPEN J Parenter Enteral Nutr 1990; 14(suppl):139S-146S Kudsk KA, Croce MA, Fabian TC, et al. Enteral versus parenteral feeding: effects on septic morbidity after blunt and penetrating abdominal trauma. Ann Surg 1992; 215:503-13 Moore FA, Feliciano DV, Andrassy RJ, et al. Early enteral feeding, compared with parenteral, reduces postoperative septic complications: the results of a meta-analysis. Ann Surg 1992; 216:172-83 Young B, Ott L, Twyman D, et al. The effect of nutritional support on outcome from severe head injury. J Neurosurg 1987; 67:668-76 Detsky AS, Baker JP, O’Rourke K, et al. Perioperative parenteral nutrition: a meta-analysis. Ann Intern Med 1987; 107:195-203 The Veterans Affairs Total Parenteral Nutrition Cooperative Study Group. Perioperative total parenteral nutrition in surgical patients. N Engl J Med 1991; 325:525-32 American College of Physicians. Parenteral nutrition in patients receiving cancer chemotherapy. Ann Intern Med 1989; 110:734-36 Szeluga DJ, Stuart RK, Brookmeyer R, et al. Nutritional support of bone marrow transplant recipients: a prospective, randomized clinical trial comparing total parenteral nutrition to an enteral feeding program. Cancer Res 1987; 47:3309-16 Kalfarentzos FE, Karavias DD, Karatzas TM, et al. Total parenteral nutrition in severe acute pancreatitis. J Am Coll Nutr 1991; 10:156-62 Alverdy JC, Burke D. Total parenteral nutrition: iatrogenic immunosuppression. Nutrition 1992; 8:359-65 Alverdy JC, Aoys E, Moss GS. Total parenteral nutrition promotes bacterial translocation from the gut. Surgery 1988; 104:185-90 Spaeth G, Berg RD, Specian RD, et al. Food without fiber promotes bacterial translocation from the gut. Surgery 1990; 108:240-47 Kearns PJ, Young H, Garcia G, et al. Accelerated improvement of alcoholic liver disease with enteral nutrition. Gastroenterology 1992; 102:200-05 Bower RH, Cerra FB, Bershadsky B, et al. Early enteral administration of a formula (Impact) supplemented with arginine, nucleotides, and fish oil in intensive care unit patients: results of a multicenter, prospective, randomized clinical trial. Crit Care Med 1995; 23:436-49 CHEST / 111 / 3 / MARCH, 1997
777
36 Orr ME, Ryder MA. Vascular access devices: perspectives on designs, complications and management. Nutr Clin Prac 1993; 8:145-52 37 Richet H, Hubert B, Nitemberg G, et al. Prospective multicenter study of vascular-catheter-related complications and risk factors for positive central-catheter cultures in intensive care unit patients. J Clin Microbiol 1990; 28:2520-25 38 Gil RT, Kruse JA, Thill-Baharozian MC, et al. Triple- vs single-lumen central venous catheters: a prospective study in a critically ill population. Arch Intern Med 1989; 149:1139-43 39 Montecalvo MA, Steger KA, Farber HW, et al. Nutritional outcome and pneumonia in critical care patients randomized to gastric versus jejunal tube feedings. Crit Care Med 1992; 20:1377-87 40 Jacobs S, Chang RWS, Lee B, et al. Continuous enteral feeding: a major cause of pneumonia among ventilated intensive care unit patients. JPEN J Parenter Enteral Nutr 1990; 14:353-56 41 Shronts EP, Cerra FB. The rational use of applied nutrition in the surgical setting. In: Paparella M, Shumrick DA, Gluckman JL, et al, eds. Otolaryngology. 3rd ed. Philadelphia: WB Saunders, 1991; 1:657-66 42 Cerra FB, Shronts EP, Raup S, et al. Enteral nutrition in hypermetabolic surgical patients. Crit Care Med 1989; 17: 619-22 43 Jequier E. Measurement of energy expenditure in clinical nutritional assessment. JPEN J Parenter Enteral Nutr 1987; 11(suppl 5):86S-9S 44 Ireton-Jones CS. Indirect calorimetry. Metabolism 1988; 37:1185 44a Cerra FB. Hypermetabolism, organ failure, and metabolic support. Surgery 1987; 101:1-14 45 ACCP/SCCM Consensus Conference. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Chest 1992; 101:1644-55 46 Cerra RB, Negro F, Abrams J. APACHE II score does not
778
47
48 49 50 51 52
53 54
55 56 57
predict MOF or mortality in postoperative surgical patients. Arch Surg 1990; 125:519-22 Kinsella JE, Lokesh B, Boughton S, et al. Dietary polyunsaturated fatty acids and eicosanoids: potential effects on the modulation of inflammation and immune cells. Nutrition 1990; 6:24-44 Braun SR, Keim NL, Dixon RM, et al. The prevalence and determinants of nutritional changes in chronic obstructive pulmonary disease. Chest 1984; 86:558-63 Rochester DF, Esau SA. Malnutrition and the respiratory system. Chest 1984; 85:411-15 Wilson DO, Rogers RM, Sanders MH, et al. Nutritional intervention in malnourished patients with emphysema. Am Rev Respir Dis 1986; 134:672-77 Wilson DO, Donahue M, Rogers RM, et al. Metabolic rate and weight loss in obstructive lung disease. JPEN J Parenter Enteral Nutr 1990; 14:7-11 Donahoe M, Rogers RM, Wilson DO, et al. Oxygen consumption of the respiratory muscles in normal and malnourished patients with chronic obstructive pulmonary disease. Am Rev Respir Dis 1989; 140:385-91 Dark DS, Pingleton SK, Kerby GR. Hypercapnia during weaning: a complication of nutritional support. Chest 1985; 88:141-43 Talpers SS, Romberger DJ, Bunce SB, et al. Nutritionally associated increased carbon dioxide production: excess total calories vs high proportion of carbohydrate calories. Chest 1992; 102:551-55 Askanazi J, Weissman C, LaSala PA, et al. Effect of protein intake on ventilatory drive. Anesthesiology 1984; 60:106-10 Aubier M, Murciano D, Lecocguic Y, et al. Effect of hypophosphatemia on diaphragmatic contractility in patients with acute respiratory failure. N Engl J Med 1985; 313:420-24 Aubier M, Viires N, Piquet J, et al. Effect of hypocalcemia on diaphragmatic strength generation. J Appl Physiol 1985; 58:2054-61
Consensus Statement
