Ratings for the strength of the recommendations (Strong, Fair, Weak, Consensus, Insufficient Evidence), conclusion grades (I-V), and statement labels (Conditional versus Imperative) are defined at the end of "Major Recommendations."
Critical Illness (CI): Enteral Versus Parenteral Nutrition and Critical Illness
CI: Enteral (EN) versus Parental Nutrition (PN)
If the critically ill intensive care unit (ICU) patient is hemodynamically stable with a functional gastrointestinal (GI) tract, then EN is recommended over PN. Patients who received EN experienced less septic morbidity and fewer infectious complications than patients who received PN. In the critically ill patient, EN is associated with significant cost savings when compared to PN. There is insufficient evidence to draw conclusions about the impact of EN or PN on length of hospital stay (LOS) and mortality.
Strong, Conditional
Recommendation Strength Rationale
- Conclusion statements are Grades I and II
Critical Illness (CI): Timing of Enteral Nutrition and Critical Illness
CI: Timing of Enteral Nutrition
If the critically ill patient is adequately fluid resuscitated, then EN should be started within 24 to 48 hours following injury or admission to the ICU. Early EN is associated with a reduction in infectious complications and may reduce LOS. The impact of timing of EN on mortality has not been adequately evaluated.
Strong, Conditional
Recommendation Strength Rationale
- Conclusion statements are Grades I, II, and V
Critical Illness (CI): Immune-Enhancing Enteral Nutrition and Critical Illness
CI: Immune-Enhancing EN
Immune-enhancing EN is not recommended for routine use in critically ill patients in the ICU. Immune-enhancing EN is not associated with reduced infectious complications, LOS, reduced cost of medical care, days on mechanical ventilation or mortality in moderately to less severely ill ICU patients. Their use may be associated with increased mortality in severely ill ICU patients, although adequately-powered trials evaluating this have not been conducted. For the trauma patient, it is not recommended to routinely use immune-enhancing EN, as its use is not associated with reduced mortality, reduced LOS, reduced infectious complications or fewer days on mechanical ventilation.
Fair, Imperative
Recommendation Strength Rationale
- Conclusion statements are Grades II and III
Critical Illness (CI): Gastric versus Small Bowel Feeding Tube Placement
CI: Feeding Tube Placement
EN administered into the stomach is acceptable for most critically ill patients. Consider placing feeding tube in the small bowel when patient is in supine position or under heavy sedation. If your institution's policy is to measure gastric residual volume (GRV), then consider small bowel tube feeding placement in patients who have more than 250 mL GRV or formula reflux in two consecutive measures. Small bowel tube placement is associated with reduced GRV. Adequately-powered studies have not been conducted to evaluate the impact of GRV on aspiration pneumonia. There may be specific disease states or conditions that may warrant small bowel tube placement (e.g., fistulas, pancreatitis, gastroparesis); however, they were not evaluated at this phase of the analysis.
Fair, Conditional
Recommendation Strength Rationale
- Conclusion statements are Grades III, IV, and V
Critical Illness (CI): Blue Dye Use and Critical Illness
CI: Blue Dye Use and Critically Ill Patients
Blue dye should not be added to EN for detection of aspiration. The risk of using blue dye outweighs any perceived benefit. The presence of blue dye in tracheal secretions is not a sensitive indicator for aspiration.
Strong, Imperative
Recommendation Strength Rationale
- Conclusion statement is Grade III
Critical Illness (CI): Blue Dye Use and Critical Illness
CI: Monitoring Patient Position
Evaluating patient position should be part of an EN monitoring plan. To decrease the incidence of aspiration pneumonia and reflux of gastric contents into the esophagus and pharynx, critically ill patients should be placed in a 45-degree head of bed elevation, if not contraindicated.
Strong, Imperative
CI: Monitoring Gastric Residual Volume
Evaluating gastric residual volume (GRV) in critically ill patients is an optional part of a monitoring plan to assess tolerance of EN. Enteral nutrition should be held when a GRV greater than or equal to 250 mL is documented on two or more consecutive occasions. Holding EN when GRV is less than 250 mL is associated with delivery of less EN. Gastric residual volume may not be a useful tool to assess the risk of aspiration pneumonia. Adequately-powered studies have not been conducted to evaluate the impact of GRV on aspiration pneumonia.
Consensus, Imperative
CI: Monitoring and Promotility Agents
If the patient exhibits a history of gastroparesis or repeated high GRVs, then consider the use of a promotility agent in critically ill ICU patients, if there are no contraindications. The use of a promotility agent (e.g., metoclopramide) has been associated with increased gastrointestinal (GI) transit, improved feeding tolerance, improved EN delivery and possibly reduced risk of aspiration.
Strong, Conditional
Recommendation Strength Rationale
- Conclusion statements are Grades I, II, III, IV, and V
Critical Illness (CI): Monitoring Delivery of Energy in Critical Illness
CI: Monitoring Delivery of Energy
Monitoring plan of critically ill patients must include a determination of daily actual EN intake. Enteral nutrition should be initiated within 48 hours of injury or admission and average intake actually delivered within the first week should be at least 60% to 70% of total estimated energy requirements as determined in the assessment. Provision of EN within this time frame and at this level may be associated with a decreased LOS, days on the mechanical ventilation and infectious complications.
Fair, Imperative
Recommendation Strength Rationale
- Conclusion statements are Grades II and III
Critical Illness (CI): Blood Glucose Control
CI: Blood Glucose Control and Critically Ill Patients
Evidence indicates that blood glucose under 140 mg/dL is associated with decreased mortality, LOS and infectious complications in critically ill patients. Dietitians should promote attainment of these levels for blood glucose (BG) control.
Strong, Imperative
CI: Role of Dietitian and Blood Glucose Control
Dietitians should promote attainment of strict glycemic control (80 to 110 mg/dL) to reduce time on mechanical ventilation in critically ill medical ICU patients.
Strong, Imperative
Recommendation Strength Rationale
- Conclusion statements are Grades I, II and III
Critical Illness (CI): Gas Collection Devices
CI: Gas Collection Devices and Air Leaks
Use rigorous adherence to manufacturers' equipment guidelines to prevent air leaks. Air leaks will result in resting metabolic rate (RMR) measurement errors.
Weak, Imperative
CI: Gas Collection Devices and Accuracy
Further studies comparing modern gas collection devices (including rigid canopies, facemasks, tubing connections, sampling lines and mouthpieces with nose clips) are needed in clinical populations. Inaccurate gas collection will result in an inaccurate measurement.
Insufficient Evidence, Imperative
Recommendation Strength Rationale
- Conclusion statement is Grade III
Critical Illness (CI): Impact of Thermic Effect of Feeding on Resting Metabolic Rate—Critical Illness
CI: Thermal effect (TEF) of Continuous Feeding on Resting Metabolic Rate (RMR)
If a critically ill patient is continuously receiving any energy source (e.g., intravenous fluids, EN or PN), the rate and concentration should remain unchanged during the 24-hour period before and during RMR measure. After 24-hour equilibration, the impact of the TEF on RMR is constant and indirect calorimetry measurements can proceed.
Fair, Conditional
CI: TEF of Intermittent Feeding on RMR
If a critically ill patient receives intermittent EN above 400 kcal per feeding, then hold feedings for a minimum of five hours before measuring RMR. When a five-hour fast is not clinically feasible or when a small feeding (<400 kcal) is given, a four-hour fast is allowed. Measuring RMR during the time of the TEF will produce inaccurately high values.
Weak, Conditional
Recommendation Strength Rationale
- Conclusion statements are Grades II and III
Critical Illness (CI): Effects of Different Length Rest Periods on Resting Metabolic Rate (RMR) in Critically Ill Patients
CI: Rest Periods and RMR
Allow a rest of 30 minutes prior to RMR measurement in critically ill patients.
Consensus, Imperative
CI: Rest Period and Accuracy of RMR
If the critically ill patient has undergone a nursing activity or medical procedure (e.g., suctioning, wound care, central venous access or ventilator setting change), then employ a 30-minute rest after procedures to achieve a resting state during RMR measurement. Measuring RMR before the 30-minute period may be inaccurate due to patient instability or ventilator gas re-equilibration.
Consensus, Conditional
Recommendation Strength Rationale
- Conclusion statement is Grade IV
Critical Illness (CI): Impact of Environmental Factors on Resting Metabolic Rate (RMR) Measurement: Noise, Lighting and Temperature
CI: Impact of Environmental Factors on RMR
Ensure that the room is comfortably quiet and the light is not providing heat or discomfort for the patient. Noise and light may cause erroneous measures of RMR if the critically ill patient's state of rest is disturbed.
Consensus, Imperative
CI: Impact of Room Temperature on RMR
Recommend a room temperature 20 to 25 degrees Celsius (68 to 77 degrees Fahrenheit). When the room's temperature is too cold, RMR is overestimated in critically ill patients by shivering or non-shivering thermogenesis, as the body adapts.
Weak, Imperative
Recommendation Strength Rationale
- Conclusion statements are Grades III and IV
Critical Illness (CI): Impact of Environmental Factors and RMR Measurement: Physical Comfort/Posture - Critical Illness
CI: Environmental Factors and RMR
Ensure that each critically ill patient is in a physically comfortable posture before proceeding with the test, because discomfort will result in erroneously high RMR measures. Make sure that repeated measures are taken in the same position to ensure comparability of data.
Insufficient Evidence, Imperative
Recommendation Strength Rationale
- Conclusion statement is Grade V
Critical Illness (CI): Steady State Measurement Conditions and Number of Measurements in 24-Hour Period
CI: Steady State Measurement of RMR
For ventilated patients, if a steady state is achieved, then a single measure is adequate to describe RMR. To achieve a steady state, discard the first five minutes of measurement. Then achieve a five-minute period with coefficient of variation (CV) = 5% for oxygen consumption and carbon dioxide production. An alternate protocol can be 25 minutes in duration if a CV of 10% is achieved. If proper attention is given to achieving resting conditions, 80% or more of RMR measures in ventilator patients will be in steady state. Sedation improves the likelihood of obtaining steady state measures.
Strong, Imperative
CI: Non-Steady State Measurement Conditions
There are published data that were not in steady state, but were still reasonably close to steady state measures. When steady state is not achieved, interpret the results carefully. If the non-steady state conditions are chronic (e.g., patient posturing), then higher measures may reflect actual energy expenditure. If non-steady state conditions are episodic (e.g., ventilator change, nursing intervention, anxiety, coughing, sneezing, movement), RMR measures should be taken at a separate time.
Consensus, Conditional
Recommendation Strength Rationale
- Conclusion statement is Grade I
Critical Illness (CI): Respiratory Quotient as a Method to Detect Measurement Error
CI: Respiratory Quotient
If Respiratory Quotient (RQ) is below 0.7 or above 1.0, then repeated measures are necessary under more optimal conditions. An RQ under 0.70 suggests hypoventilation (inadequate removal of metabolic carbon dioxide from the blood to the lung) or prolonged fasting. An RQ above 1.0, in the absence of overfeeding, suggests hyperventilation (removal of carbon dioxide from the blood to the lung in excess of the amount produced by metabolism) or inaccurate gas collection.
Strong, Conditional
Recommendation Strength Rationale
- Conclusion statement is Grade II
Critical Illness (CI): Determination of Resting Metabolic Rate (RMR)
CI: Indirect Calorimetry to Determine RMR
Indirect calorimetry is the standard for determination of RMR in critically ill patients since RMR based on measurement is more accurate than estimation using predictive equations.
Strong, Imperative
CI: RMR Predictive Equations for Non-Obese Patients
If predictive equations are needed in non-obese, critically ill patients, consider using one of the following, as they have the best prediction accuracy of equations studied (listed in order of accuracy): Penn State, 2003a (79%), Swinamer (55%) and Ireton-Jones, 1992 (52%) (see Supporting Evidence in the original guideline document). In some individuals, errors between predicted and actual energy needs will result in under- or over-feeding.
Fair, Conditional
CI: Inappropriate RMR Predictive Equations for This Population
The Harris-Benedict (with or without activity and stress factors), the Ireton-Jones, 1997, and the Fick equation (see Supporting Evidence in the original guideline document) should not be considered for use in RMR determination in critically ill patients, as these equations do not have adequate prediction accuracy. In addition, the Mifflin-St. Jeor equation should not be considered for use in critically ill patients, as it was developed for healthy people and has not been well researched in the critically ill population.
Strong, Imperative
CI: RMR Predictive Equations for Obese Patients
If predictive equations are needed for critically ill mechanically ventilated individuals who are obese, consider using Ireton-Jones, 1992 or Penn State, 1998 (see Supporting Evidence in the original guideline document), as they have the best prediction accuracy of equations studied. In some individuals, errors between predicted and actual energy needs will result in under- or over-feeding.
Fair, Conditional
Recommendation Strength Rationale
- Conclusion statements are Grades I, II, III, and V
Definitions:
Conditional versus Imperative Recommendations
Recommendations can be worded as conditional or imperative statements. Conditional statements clearly define a specific situation, while imperative statements are broadly applicable to the target population without restraints on their pertinence. More specifically, a conditional recommendation can be stated in if/then terminology (e.g., If an individual does not eat food sources of omega-3 fatty acids, then 1g of EPA and DHA omega-3 fatty acid supplements may be recommended for secondary prevention).
In contrast, imperative recommendations "require," or "must," or "should achieve certain goals," but do not contain conditional text that would limit their applicability to specified circumstances. (e.g., Portion control should be included as part of a comprehensive weight management program. Portion control at meals and snacks results in reduced energy intake and weight loss).
Levels of Evidence
| Strength of Evidence Elements |
Grade I
Good/Strong
|
Grade II
Fair
|
Grade III
Limited/Weak
|
Grade IV
Expert Opinion Only
|
Grade V
Grade Not Assignable
|
Quality
- Scientific rigor/validity
- Considers design and execution
|
Studies of strong design for question
Free from design flaws, bias and execution problems
|
Studies of strong design for question with minor methodological concerns
OR
Only studies of weaker study design for question
|
Studies of weak design for answering the question
OR
Inconclusive findings due to design flaws, bias or execution problems
|
No studies available
Conclusion based on usual practice, expert consensus, clinical experience, opinion, or extrapolation from basic research
|
No evidence that pertains to question being addressed |
Consistency
Of findings across studies
|
Findings generally consistent in direction and size of effect or degree of association, and statistical significance with minor exceptions at most |
Inconsistency among results of studies with strong design
OR
Consistency with minor exceptions across studies of weaker designs
|
Unexplained inconsistency among results from different studies
OR
Single study unconfirmed by other studies
|
Conclusion supported solely by statements of informed nutrition or medical commentators |
NA |
Quantity
- Number of studies
- Number of subjects in studies
|
One to several good quality studies
Large number of subjects studies
Studies with negative results having sufficiently large sample size for adequate statistical power
|
Several studies by independent investigators
Doubts about adequacy of sample size to avoid Type I and Type II error
|
Limited number of studies
Low number of subjects studies and/or inadequate sample size within studies
|
Unsubstantiated by published studies |
Relevant studies have not been done |
Clinical Impact
- Importance of studies outcomes
- Magnitude of effect
|
Studied outcome relates directly to the question
Size of effect is clinically meaningful
Significant (statistical) difference is large
|
Some doubt about the statistical or clinical significance of effect |
Studies outcome is an intermediate outcome or surrogate for the true outcome of interest
OR
Size of effect is small or lacks statistical and/or clinical significance
|
Objective data unavailable |
Indicates area for future research |
Generalizability
To population of interest
|
Studied population, intervention and outcomes are free from serious doubts about generalizability |
Minor doubts about generalizability |
Serious doubts about generalizability due to narrow or different study population, intervention or outcomes studied |
Generalizability limited to scope of experience |
NA |
The levels of evidence were based on the grading system from: Greer N, Mosser G, Logan G, Wagstrom Halaas G. A practical approach to evidence grading. Jt Comm. J Qual Improv. 2000; 26:700-712. In September 2004, The ADA Research Committee modified the grading system to this current version.
Criteria for Recommendation Rating
| Statement Rating |
Definition |
Implication for Practice |
| Strong |
A Strong recommendation means that the workgroup believes that the benefits of the recommended approach clearly exceed the harms (or that the harms clearly exceed the benefits in the case of a strong negative recommendation), and that the quality of the supporting evidence is excellent/good (grade I or II)*. In some clearly identified circumstances, strong recommendations may be made based on lesser evidence when high-quality evidence is impossible to obtain and the anticipated benefits strongly outweigh the harms. |
Practitioners should follow a Strong recommendation unless a clear and compelling rationale for an alternative approach is present. |
| Fair |
A Fair recommendation means that the workgroup believes that the benefits exceed the harms (or that the harms clearly exceed the benefits in the case of a negative recommendation), but the quality of evidence is not as strong (grade II or III)*. In some clearly identified circumstances, recommendations may be made based on lesser evidence when high-quality evidence is impossible to obtain and the anticipated benefits outweigh the harms. |
Practitioners should generally follow a Fair recommendation but remain alert to new information and be sensitive to patient preferences. |
| Weak |
A Weak recommendation means that the quality of evidence that exists is suspect or that well-done studies (grade I, II, or III)* show little clear advantage to one approach versus another. |
Practitioners should be cautious in deciding whether to follow a recommendation classified as Weak, and should exercise judgment and be alert to emerging publications that report evidence. Patient preference should have a substantial influencing role. |
| Consensus |
A Consensus recommendation means that Expert opinion (grade IV)* supports the guideline recommendation even though the available scientific evidence did not present consistent results, or controlled trials were lacking. |
Practitioners should be flexible in deciding whether to follow a recommendation classified Consensus, although they may set boundaries on alternatives. Patient preference should have a substantial influencing role. |
| Insufficient Evidence |
An Insufficient Evidence recommendation means that there is both a lack of pertinent evidence (grade V)* and/or an unclear balance between benefits and harms. |
Practitioners should feel little constraint in deciding whether to follow a recommendation labeled as Insufficient Evidence and should exercise judgment and be alert to emerging publications that report evidence that clarifies the balance of benefit versus harm. Patient preference should have a substantial influencing role. |
*Conclusion statements are assigned a grade based on the strength of the evidence. Grade I is good; grade II, fair; grade III, limited; grade IV signifies expert opinion only and grade V indicates that a grade is not assignable because there is no evidence to support or refute the conclusion. The evidence and these grades are considered when assigning a rating (Strong, Fair, Weak, Consensus, Insufficient Evidence - see chart above) to a recommendation.
Adapted by the American Dietetic Association from the American Academy of Pediatrics, Classifying Recommendations for Clinical Practice Guideline, Pediatrics. 2004;114;874-877.
Statement Labels (Conditional versus Imperative)
Conditional statements clearly define a specific situation, while imperative statements are broadly applicable to the target population without restraints on their pertinence. A conditional recommendation can be stated in if/then terminology, with the condition of application listed.
