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Critical Illness

CI: Executive Summary of Recommendations (2006)

Critical Illness (2005) Evidence-Based Nutrition Practice Guideline

Executive Summary of Recommendations

Critical Illness Nutrition Practice Recommendations

Below are the major recommendations, and ratings for the Critical Illness (2005) Evidence-Based Nutrition Practice Guideline. Click here to view the Guideline Overview. More detail (including the evidence analysis supporting these recommendations) is available to Academy members and subscribers under Major Recommendations.

To see a description of the Academy Recommendation Rating Scheme click here

Enteral versus Parenteral Nutrition

CI: Enteral versus Parenteral Nutrition and Critical Illness 2006

CI: Enteral vs Parenteral Nutrition

If the critically ill ICU patient is hemodynamically stable with a functional 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 LOS and mortality.

Strong, Conditional

Timing of Feeding

CI: Timing of Enteral Nutrition and Critical Illness 2006

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

Immune-Enhancing Enteral Formula

CI: Immune-Enhancing Enteral Nutrition and Critical Illness 2006

CI: Immune-enhancing enteral nutrition

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

Feeding Tube Site

CI: Gastric versus Small Bowel Feeding Tube Placement 2006

CI: Feeding Tube Placement

Enteral Nutrition (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 250ml 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, gastroporesis), however they were not evaluated at this phase of the analysis.

Fair, Conditional

Blue Dye Use

CI: Blue Dye Use and Critical Illness 2006

CI: Blue Dye use and critically ill patients

Blue dye should not be added to enteral nutrition (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

Monitoring Criteria in Critical Care

CI: Monitoring Criteria in Critical Illness 2006

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 pharnyx, 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 250ml is documented on two or more consecutive occasions. Holding EN when GRV is less than 250ml 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 GI transit, improved feeding tolerance, improved EN delivery and possibly reduced risk of aspiration.

Strong, Conditional

Monitoring Delivery of Energy

CI: Monitoring Delivery of Energy in Critical Illness 2006

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 60-70% 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

Blood Glucose Control

  09/29/09 Recommendation removed and currently under revision.

Energy Expenditure


CI: Gas Collection Devices 2006

CI: Gas Collection Devices and Air Leaks

Use rigorous adherence to manufacturers' equipment guidelines to prevent air leaks. Air leaks will result in 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

Patient Condition

CI: Impact of Thermic Effect of Feeding on RMR 2006

CI: Thermic effect of continuous feeding on 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: Thermic effect of intermittent feeding on RMR

If a critically ill patient receives intermittent EN above 400kcal 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 (<400kcal) is given, a four-hour fast is allowed. Measuring RMR during the time of the TEF will produce inaccurately high values.

Weak, Conditional

CI: Effects of Different Length Rest Periods on RMR in Critically Ill Patients 2006

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


CI: Impact of Environmental Factors on RMR Measurement: Noise, Lighting and Temperature 2006

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

CI: Impact of Environmental Factors on RMR Measurement: Physical Comfort/Posture 2006

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

Test Interpretation

CI: Steady State Measurement Conditions and Number of Measurements in a 24-Hour Period 2006

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 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

CI: Respiratory Quotient as a Method to Detect Measurement Error 2006

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

 Energy Assessment

CI: Determination of Resting Metabolic Rate (RMR) 2006

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%). 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 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, 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