Enteral Nutrition

General Nutritional Guidelines

  • See Nutrition (see Nutrition, [[Nutrition]])

Enteral Nutrition vs Total Parenteral Nutrition (TPN) (see Total Parenteral Nutrition, [[Total Parenteral Nutrition]])

Clinical Efficacy

  • Systematic Review of Enteral vs Parenteral Nutrition in the ICU (Nutrition, 2004) [MEDLINE]
    • Enteral Nutrition Decreases Infectious Complications, as Compared to Parenteral Nutrition
    • Enteral Nutrition is Less Expensive than Parenteral Nutrition
  • EPaNIC Trial Comparing Early vs Late Initiation of TPN (NEJM, 2011) [MEDLINE]: Belgian randomized multi-center trial comparing early initiation of TPN (European guidelines: within 48 hrs of ICU admission; n = 2312) with late initiation (American and Canadian guidelines: within 8 days of ICU admission; n = 2328) in adults in the ICU
    • No Difference in ICU Mortality Rate, Hospital Mortality, and 90-Day Mortality Rate Between the Groups
    • Late-Initiation Group Had a 6.3% Increase in Likelihood of Being Discharged Alive Earlier from the ICU and Hospital
    • Late-Initiation Group Had Fewer ICU Infections (22.8% vs. 26.2%, p = 0.008)
    • Late-Initiation Group Had a Lower Incidence of Cholestasis (p < 0.001)
    • Late-Initiation Group Had a Relative Reduction of 9.7% in the Proportion of Patients Requiring >2 Days of Mechanical Ventilation (p = 0.006)
    • Late-Initiation Group Had a Median Reduction of 3 Days in the Duration of Renal Replacement Therapy (p = 0.008)
    • Late-Initiation Group Had a Mean Reduction in Health Care Costs of About $1,600 (p = 0.04)
    • Late-Initiation Group Had No Decrease in Functional Status at Hospital Discharge
  • Study of Early Parenteral Nutrition in Critically Ill Patients with Short-Term Relative Contraindications to Early Enteral Nutrition (JAMA, 2013) [MEDLINE]: n = 1372 patients
    • No Impact on 60-Day Mortality Rate, as Compared to Standard Care
    • Early Parenteral Nutrition Strategy Resulted in Fewer Invasive Ventilation Days, But Had No Effect on ICU or Hospital Stay
  • Swiss Randomized Trial of Supplemental TPN in Critically Ill Patients (Lancet, 2013) [MEDLINE]: n = 305 patients
    • Supplemental TPN (in Addition to Enteral Nutrition) Starting 4 Days After ICU Admission Decreased Nosocomial Infection Rates
  • British CALORIES Trial Comparing Early Enteral vs Parenteral Nutrition in the ICU (NEJM, 2014) [MEDLINE]: randomized trial in 33 English ICU’s comparing enteral vs parenteral nutrition (n = 2388)
    • No Difference in 30-day Mortality Between the Groups
    • Caloric Intake was Similar in the Groups, with the Target Intake Not Achieved in Most Patients
    • Total Parenteral Nutrition Group Had Significantly Decreased Rates of Hypoglycemia and Vomiting, as Compared to the Enteral Group
    • No Difference in Rate of Infectious Complications or Other Adverse Events

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Enteral Nutrition Should Be Used Over TPN (Quality of Evidence: Very Low-Low)
    • Enteral Nutrition is Associated with Decreased Infectious Complications (Pneumonia and Central Line Infections in Most Patients/Abdominal Abscess in Trauma Patients) and Decreased ICU Length of Stay
  • In Patients with Low Nutrition Risk (NRS 2002 ≤3 or NUTRIC score ≤5), Exclusive TPN Should Be Withheld for the First 7 Days Following ICU Admission, if PO Intake and Enteral Nutrition are Not Adequate/Possible (Quality of Evidence: Very Low)
  • In Patients with High Nutrition Risk (NRS 2002 ≥5 or NUTRIC score ≥5) or Severely Malnourished, Exclusive TPN Should Be Started as Soon as Possible Following ICU Admission, if PO Intake and Enteral Nutrition are Not Adequate/Possible (Quality of Evidence: Expert Consensus)
  • In Patients with Low or High Nutrition Risk, Supplemental TPN Should Be Considered After 7-10 Days if Unable to Meet >60% of Energy and Protein Requirements by Enteral Route Alone (Quality of Evidence: Moderate)
    • Initiating Supplemental TPN Prior to 7-10 Days May Be Harmful

Indications for Enteral Nutrition (in Specific Clinical Situations)

Enteral Nutrition in the Setting of Acute Pancreatitis (see Acute Pancreatitis, [[Acute Pancreatitis]])

Clinical Efficacy

  • Meta-Analysis of Nasogastric vs Nasojejunal Feeding in Severe Acute Pancreatitis (Crit Care, 2013) [MEDLINE]
    • Nasogastric Feeding is Safe and Well-Tolerated, as Compared to Nasojejunal Feeding
    • Critique: small study, needs to be replicated
  • Dutch PYTHON Trial Comparing Early Enteral Nutrition with Oral Intake in Severe Acute Pancreatitis (NEJM, 2014) [MEDLINE]: n = 208
    • If Oral Intake was Inadequate in the Latter Oral Intake Group (“On-Demand” Group), Enteral Nutrition was Started
    • In Patients with Acute Pancreatitis at High Risk for Complications, Early Enteral Nutrition (within 24 hrs of ED Presentation) was Not Superior to Oral Intake (Started After 72 hrs), in Terms of Decreasing the Infection Rate or Mortality Rate within 6 mo

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Definitions
    • Mild Acute Pancreatitis: absence of organ failure and local complications
    • Moderate Acute Pancreatitis: transient organ failure (SBP <90 mm Hg, pO2/FIO2 ratio ≤300, or AKI with Cr ≥1.9 mg/dL) lasting <48 hrs with presence of local complications (pseudocyst, abscess, necrosis)
    • Severe Acute Pancreatitis: persistent organ failure lasting >48 hrs from the time of admission
  • Initial Nutritional Assessment Should Evaluate Disease Severity to Guide Nutritional Therapy (Expert Consensus)
    • Since Disease Severity May Change Quickly, Frequent Reassessment of Feeding Tolerance and the Need for Specialized Nutritional Therapy is Suggested
  • Mild Acute Pancreatitis
    • Oral Diet (Advanced As Tolerated) is Recommended (Quality of Evidence: Very Low)
    • If an Unexpected Complication Develops or There is a Failure to Advance Oral Diet within 7 Days, Specialized Nutritional Therapy Should Be Considered (Quality of Evidence: Very Low)
  • Moderate-Severe Acute Pancreatitis
    • Nasogastric tube Placement and Start of Trophic Tube Feedings with Advancement (As Tolerated) to Target Rate Within 24-48 hrs is Recommended (Quality of Evidence: Very Low)
    • If Intolerance Develops Occurs, the Following Measures Should Be Taken to Improve Tolerance (Expert Consensus)
      • Minimizing the Period of Ileus by Starting Enteral Nutrition as Soon as Possible within the First 48 hrs of Admission to the ICU
      • Diverting the Infusion of Enteral Feeding to a More Distal Gastrointestinal Tract Site (i.e. Jejunal Feeding): feeding into the jejunum is associated with a lesser degree of pancreatic stimulation, which increases the likelihood of the feedings being successful and circumvents the problem of gastric dysmotility
      • Changing from a Standard Polymeric Enteral Feeding Formula to One Which Contains Small Peptides and Medium Chain Triglycerides (MCT) or to One that is a Nearly Fat-Free Elemental Formulation
      • Switching from Bolus to Continuous Infusion of Enteral Feeding
  • Severe Acute Pancreatitis
    • Standard Polymeric Tube Feed Formulation is Recommended (Quality of Evidence: Very Low)
    • Enteral Nutrition is Recommended (by Gastric or Jejunal Route) Over Total Parenteral Nutrition (TPN) in Severe Pancreatitis (Quality of Evidence: Low)
    • No Difference Between Gastric or Jejunal Feeding with Regard to Tolerance or Clinical Outcome (Quality of Evidence: Low)
    • Probiotics Should Be Considered with Early Tube Feeding in Severe Pancreatitis (Quality of Evidence: Low)
    • When Enteral Nutrition is Not Possible, Parenteral Nutrition Can Be Considered After 1 Week From the Onset of the Acute Pancreatitis Episode (Expert Consensus)

Enteral Nutrition in the Setting of Acute Respiratory Distress Syndrome (ARDS) (see Acute Respiratory Distress Syndrome, [[Acute Respiratory Distress Syndrome]])

Clinical Efficacy (General)

  • Effect of Supplementation with Omega-3 (n-3) Fatty Acids (Docosahexaenoic Acid = DHA, Eicosapentaenoic Acid = EPA), γ-Linolenic Acid, and Antioxidants in Acute Lung Injury (JAMA, 2011) [MEDLINE]
    • Supplementation Had No Clinical Benefit, in Terms of Ventilator-Free Days or Other Clinical Outcomes: may be harmful
  • EDEN Trial of Enteral Nutrition in Acute Lung Injury (JAMA, 2012) [MEDLINE]
    • Initial Trophic Feeding (For Up to 6 Days) Did Not Improve Ventilator Days, 60-Day Mortality, or Infectious Complications, as Compared to Full Feeding
    • Full Feeding Group Had More Gastrointestinal Intolerance (Vomiting, Constipation, and Elevated Gastric Residual Volumes): they received more pro-kinetic agents

Clinical Efficacy (During Prone Ventilation)

  • Study of Early Enteral Nutrition in Association with Prone Ventilation (Crit Care Med, 2004) [MEDLINE]
    • Early Enteral Nutrition is Poorly-Tolerated in Patients Who are Prone-Ventilated
    • Prokinetic Agents, Transpyloric Feeding, and Semirecumbency Should Be Considered to Enhance Gastric Emptying and to Prevent Vomiting in This Population
  • Study of Head of Bed Elevation in Enteral Nutrition in Association with Prone Ventilation (Clin Nutr, 2010) [MEDLINE]:
    • Elevation (25 Degrees) Increased Acceleration of Tube Feedings to Target Rate
    • Erythromycin Improved Delivery of Enteral Nutrition
  • Study of Enteral Nutrition in Association with Prone Ventilation (J Parenter Enteral Nutr, 2014)
    • Enteral Nutrition in Association with Prone Ventilation is Feasible, Safe, and Not Associated with an Increased Risk of Gastrointestinal Complications

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • High Fat/Low Carbohydrate Tube Feedings are Not Recommended in Patients with Acute Respiratory Failure (Quality of Evidence: Very Low)
  • Either Trophic or Full Feedings are Acceptable in ARDS with an Expected Duration of Mechanical Ventilation ≥72 hrs (Quality of Evidence: High)
    • Both Trophic and Full Feeding Strategies Have Similar Outcomes for the First Week of Hospitalization
  • In Acute Respiratory Failure, Fluid-Restricted, Energy-Dense Enteral Formulations Should Be Considered, Especially in the State of Volume Overload (Quality of Evidence: Expert Consensus)
  • Supplemental Antioxidant Vitamins (Vitamins E and C) and Trace Minerals (Selenium, Zinc, Copper) May Be Beneficial in Burns, Trauma, Critical Illness Requiring Mechanical Ventilation (Quality of Evidence: Low)
  • Supplemental Omega-3 (n-3) Fatty Acids (Docosahexaenoic Acid = DHA, Eicosapentaenoic Acid = EPA) Are Not Recommended in ARDS

Enteral Nutrition in the Setting of Hemodynamic Instability

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Tube Feedings Should Be Withheld Until the Patient is Fully Resuscitated and/or Stable (Quality of Evidence: Expert Consensus)

Enteral Nutrition in the Setting of Liver Disease (see Cirrhosis, [[Cirrhosis]])

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Dry Weight/Usual Weight Should Be Used Instead of Actual Weight for Predictive Equations (Quality of Evidence: Expert Consensus): due to ascites, intravascular volume depletion, edema, portal hypertension, and hypoalbuminemia
  • Routine Tube Feeding Formulations are Recommended Over Branched-Chain Amino Aid (BCAA) Formulations in Patients with Hepatic Encephalopathy (Quality of Evidence: Expert Consensus)
  • Enteral Nutrition Should Be Used Preferentially in the Setting of Liver Disease (Quality of Evidence: Expert Consensus): due to the risk of worsened hepatic dysfunction with prolonged TPN use

Enteral Nutrition in the Setting of an Open Abdomen

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Early Tube Feeding Within 24-48 hrs is Recommended in the Absence of Bowel Injury (Quality of Evidence: Expert Consensus)

Enteral Nutrition in the Setting of Renal Disease (see Acute Kidney Injury, [[Acute Kidney Injury]] and Chronic Kidney Disease, [[Chronic Kidney Disease]])

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Patients Receiving Frequent Hemodialysis or Continuous Renal Replacement Therapy (CRRT) SHould Receive Increased Protein (Max: 2.5 g/kg/day)

Enteral Nutrition in the Setting of Sepsis (see Sepsis, [[Sepsis]])

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Use of Exclusive/Supplemental Parenteral Nutrition are Not Recommended in the Acute Phase of Sepsis, Regardless of Degree of Nutrition Risk (Quality of Evidence: Very Low)
  • Benefits of Use of Selenium, Zinc, and Antioxidants in Sepsis are Unclear (Quality of Evidence: Moderate)
  • Immune Modulating Formulations are Not Recommended in Sepsis (Quality of Evidence: Moderate)

Enteral Nutrition in the Setting of Trauma

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Immune-Modulating Formulations Containing Arginine and Fish Oils Should Be Considered in Severe Trauma (Quality of Evidence: Very Low)

Enteral Nutrition in the Setting of Traumatic Brain Injury (TBI) (see Traumatic Brain Injury, [[Traumatic Brain Injury]])

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Immune-Modulating Formulations Containing Arginine and EPA/DHA are Recommended in Traumatic Brain Injury (TBI) (Quality of Evidence: Expert Consensus)
  • Supplemental Antioxidant Vitamins (Vitamins E and C) and Trace Minerals (Selenium, Zinc, Copper) May Be Beneficial in Burns, Trauma, Critical Illness Requiring Mechanical Ventilation (Quality of Evidence: Low)

Administration

Enteral Nutrition Formulation

Clinical Efficacy

  • Trial of Glutamine and Antioxidants in Critically Ill Patients with Mutiorgan Failure on Mechanical Ventilation (NEJM, 2013) [MEDLINE]: early provision of glutamine or antioxidants did not improve clinical outcomes, and glutamine was associated with an increase in mortality among critically ill patients with multiorgan failure
  • OMEGA Trial of Enteral Omega-3 Fatty Acids, Gamma-Linolenic Acid, and Antioxidants in Acute Lung Injury (JAMA, 2011) (JAMA, 2011) [MEDLINE]: did not improve the primary end point of ventilator-free days or other clinical outcomes in patients with acute lung injury and may be harmful

Recommendations-Fiber Content (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Fermentable Soluble Fiber (fructo-oligossaccharides or inulin; 10-20 g/day) is Suggested as an Additive in All Hemodynamically Stable MICU/SICU Patients on a Standard Enteral Formulation, if There is Evidence of Diarrhea (Quality of Evidence: Expert Consensus)

Recommendations-Protein Content (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Enteral Nutrition Should Contain 1.2–2.0 g/kg of Actual Body Weight Per Day (Quality of Evidence: Very Low): higher in burn or trauma settings

Recommendations-Formulation/Supplementation (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Standard Polymeric Formulas Should Be Used Over Specialty/Disease-Specific Formulas (Quality of Evidence: Expert Consensus)
  • Immune-Modulating Formulations (Arginine with Other Agents, Including Eicosapentaenoic Acid = EPA, Docosahexaenoic Acid = DHA, Glutamine, Nucleic acid) Should Not Be Routinely Used in the MICU (Quality of Evidence: Very Low)
  • Immune-Modulating Formulations Containing Arginine and Fish Oils Should Be Considered in Severe Trauma (Quality of Evidence: Very Low)
  • Immune-Modulating Formulations Containing Arginine and Fish Oils Should Be Used in Postoperative Patients in the SICU
  • Immune-Modulating Formulations Containing Arginine and EPA/DHA are Recommended in Traumatic Brain Injury (TBI)
  • High Fat/Low Carbohydrate Tube Feedings are Not Recommended in Patients with Acute Respiratory Failure (Quality of Evidence: Very Low)
  • Supplemental Omega-3 (n-3) Fatty Acids (Docosahexaenoic Acid = DHA, Eicosapentaenoic Acid = EPA) Are Not Recommended in ARDS
  • Supplemental Antioxidant Vitamins (Vitamins E and C) and Trace Minerals (Selenium, Zinc, Copper) May Be Beneficial in Burns, Trauma, Critical Illness Requiring Mechanical Ventilation (Quality of Evidence: Low)
  • Supplemental Glutamine is Not Recommended in Critically Ill Patients (Quality of Evidence: Moderate)

Timing of Enteral Nutrition Initiation

Rationale

  • Enteral Nutrition Maintains the Functional Integrity of the Gut: by maintaining tight junctions between the intraepithelial cells, stimulating blood flow, and inducing the release of trophic endogenous agents (cholecystokinin, gastrin, bombesin, and bile salts)
  • Enteral Nutrition Modulates Stress and Systemic Immune Responses
  • Enteral Nutrition Attenuates Disease Severity

Clinical Efficacy

  • Trial of Early Enhanced Enteral Nutrition in Mechanically Ventilated Patients with Head Injury (Crit Care Med, 1999) [MEDLINE]: enhanced enter nutrition appears to accelerate neurologic recovery and reduces both the incidence of major complications (infectious complications, etc) and post-injury inflammatory responses (C-reactive protein/albumin ratio)
  • Study of “Best Achievable” Practice for Nutrition in the ICU (Crit Care Med, 2010) [MEDLINE]
    • Average Time to Start Enteral Nutrition in Study: 46.5 hrs
    • Average Nutritional Adequacy for Energy Needs: only 59%
    • Average Nutritional Adequacy for Protein Needs: only 60%
  • EDEN Trial of Enteral Nutrition in Acute Lung Injury (JAMA, 2012) [MEDLINE]
    • Initial Trophic Feeding (For Up to 6 Days) Did Not Improve Ventilator Days, 60-Day Mortality, or Infectious Complications, as Compared to Full Feeding
    • Full Feeding Group Had More Gastrointestinal Intolerance (Vomiting, Constipation, and Elevated Gastric Residual Volumes): they received more promotility agents

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • Enteral Nutrition Should Be Initiated Within 24-48 hrs in Patients Who are Unable to Maintain Their Nutrition Voluntarily (Quality of Evidence: Very Low)
  • Presence of Bowel Sounds/Passing of Flatus or Stool are Not Required for the Initiation of Enteral Nutrition (Quality of Evidence: Expert Consensus)
  • In Patients at High Nutrition Risk (NRS 2002 ≥5 or NUTRIC Score ≥5, Without IL-6), Enteral Nutrition Should Be Advanced as Quickly As Tolerated Within the First 24-48 hrs (Quality of Evidence: Expert Consensus): attempt to provide >80% of estimated/calculated goal energy and protein within 48–72 hrs to achieve the benefit of enteral nutrition over the first week of hospitalization
  • In Severely Malnourished or High Risk Patients, Hypocaloric Feeding (≤20 kcal/ kg/d or 80% of Estimated Energy Needs) with Adequate Protein (≥1.2 g protein/kg/day) Should Be Considered Over the First Week in the ICU (Quality of Evidence: Expert Consensus)

Site of Enteral Nutrition Delivery

Rationale

  • Changing the Level of Tube Feeding Infusion From the Stomach to the Small Bowel Decreases the Incidence of Regurgitation, Aspiration, and Pneumonia

Efficacy

  • Multi-Center Randomized Trial Comparing Nasogastric vs Nasojejunal Feeding (Crit Care Med, 2012) [MEDLINE]
    • No Difference in Mortality, Length of Stay, Nutrient Delivery, and Incidence of Pneumonia

Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • In Most Critically Ill Patients, Gastric Tube Feeding is Acceptable (Quality of Evidence: Moderate-High): it is technically easier to use gastric feeding
  • In Patients at High Risk for Aspiration, Post-Pyloric Tube Feeding Should Be Used (Quality of Evidence: Moderate-High), Continuous Infusion Should Be Used (Quality of Evidence: Expert Consensus), and Promotility Agents (Metoclopramide, Erythromycin) Should Be Used (Quality of Evidence: Low)
  • Measures to Decrease Aspiration (Head of Bed 30°–45°, Chlorhexidine Mouthwash BID) Should Be Employed While Delivering Tube Feeds (Quality of Evidence: Expert Consensus)

Inadequate Delivery of Enteral Nutrition

General Comments

  • Patients are Commonly Underfed in the ICU
    • Study of “Best Achievable” Practice for Nutrition in the ICU (Crit Care Med, 2010) [MEDLINE]
      • Average Time to Start Enteral Nutrition in Study: 46.5 hrs
      • Average Nutritional Adequacy for Energy Needs: only 59%
      • Average Nutritional Adequacy for Protein Needs: only 60%

Reasons for Inadequate Delivery of Enteral Nutrition

  • Enteral Nutrition Intolerance: accounts for approximately 33% of cessation time
  • Technical Issues with Feeding Tube
  • Tube Feeding Cessation for Anticipated Diagnostic Testing/Procedures
  • Under-Prescription of Enteral Nutrition by Provider

Use of Probiotics (see Probiotics, [[Probiotics]])

Recommendations-Probiotics (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]

  • While Probiotics Appear to Be Safe in ICU Patients, They Should Only Be Used in Select Populations (Quality of Evidence: Low)
    • No Specific Recommendations are Made Regarding the Use of Probiotics

Complications/Adverse Effects of Enteral Nutrition

Endocrinologic Complications/Adverse Effects

Gastrointestinal Complications/Adverse Effects

Enteral Nutrition Intolerance

  • Factors Contributing to Enteral Nutrition Intolerance
    • Impaired Function of the Enteric Nerve and Smooth Muscles of the Gastrointestinal Tract
      • Opiates (see Opiates, [[Opiates]])
    • Inflammatory State
    • Surgery: particularly abdominal surgery
    • Electrolyte Imbalance
    • Hyperglycemia (see Hyperglycemia, [[Hyperglycemia]])
    • Sepsis (see Sepsis, [[Sepsis]])
    • Delayed Gastric Emptying
    • Disease Process
  • Clinical Assessment of Enteral Nutrition Intolerance
    • Rationale
      • Gastric Residual Volume Do Not Correlate with Incidence of Pneumonia, Regurgitation, or Aspiration
    • Clinical Efficacy
      • REGANE Trial (Intensive Care Med, 2010) [MEDLINE]
        • Gastric Residual Volumes Up to 500 ml Could be Safely Tolerated
      • NUTRIREA 1 Trial (JAMA, 2013) [MEDLINE]
        • Not Monitoring Gastric Residual Volume Did Not Increase the Incidence of Aspiration or Related Complications
    • Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]
      • Gastric Residual Volume Should Not Be Used to Monitor Enteral Nutrition (Quality of Evidence: Low): if used, cutoff for residual volume should be >500 mL
      • Tube Feedings Should Not Be Stopped Automatically for Diarrhea (Quality of Evidence: Expert Consensus)
  • Clinical Signs of Enteral Nutrition Intolerance
    • Abdominal Bloating/Distention
    • Abdominal Discomfort/Cramping/Pain (see Abdominal Pain, [[Abdominal Pain]])
    • Abnormal KUB
    • Decreased Flatus
    • Decreased Stool Output
    • Diarrhea (see Diarrhea, [[Diarrhea]])
      • Diarrhea Occurs in 15-18% of Patients on Enteral Nutrition, as Compared to 6% of Patients Who Have Not Received Enteral Nutrition (Crit Care Med, 1999) [MEDLINE] and (Nutrition, 2008) [MEDLINE]
      • Diarrhea May Result in Electrolyte Abnormalities, Dehydration, Perianal Skin Breakdown, Wound Contamination, etc
    • High Gastric Residual Volume
    • High Nasogastric Tube Output
    • Nausea/Vomiting (see Nausea and Vomiting, [[Nausea and Vomiting]])
  • Management of Enteral Nutrition Intolerance
    • Trophic Feeding Strategy
      • EDEN Trial of Enteral Nutrition in Acute Lung Injury (JAMA, 2012) [MEDLINE]
        • Initial Trophic Feeding (For Up to 6 Days) Did Not Improve Ventilator Days, 60-Day Mortality, or Infectious Complications, as Compared to Full Feeding
        • Full Feeding Group Had More Gastrointestinal Intolerance (Vomiting, Constipation, and Elevated Gastric Residual Volumes): full feeding group patients received more pro-kinetic agents
      • Permissive Underfeeding (40-60% of Calculated Caloric Requirement) vs Target (70-100% of Calculated Caloric Requirement) Enteral Feeding in Adult Critically Ill Patients (PermiT) Trial (NEJM, 2015) [MEDLINE]
        • Permissive Underfeeding Did Not Impact the 90-Day Mortality Rate, Feeding Intolerance, Incidence of Diarrhea, ICU-Acquired Infection Rate, ICU Length of Stay, or Hospital Length of Stay
    • Fiber: most commonly used (and studied) intervention for tube feeding-related diarrhea
      • Fiber Use in Patients on Vasopressors (Who Manifest Impaired Bowel Peristalsis) May Be Associated with an Increased Risk of Bezoar Formation (Nutrition, 1990) [MEDLINE]
    • Recommendations (Society of Critical Care Medicine, SCCM, and American Society for Parenteral and Enteral Nutrition, ASPEN, 2016 Guidelines) [MEDLINE]
      • Gastric Residual Volume Should Not Be Used to Monitor Enteral Nutrition (Quality of Evidence: Low): if used, cutoff for residual volume should be >500 mL
      • Tube Feedings Should Not Be Stopped Automatically for Diarrhea (Quality of Evidence: Expert Consensus)
      • Fermentable Soluble Fiber (Fructo-Oligossaccharides or Inulin; 10-20 g/day) is Suggested as an Additive in All Hemodynamically Stable MICU/SICU Patients on a Standard Enteral Formulation, if There is Evidence of Diarrhea (Quality of Evidence: Expert Consensus)

Refeeding Syndrome (see Refeeding Syndrome, [[Refeeding Syndrome]])

  • High Risk Groups for the Development of Refeeding Syndrome
    • Anorexia Nervosa (see Anorexia Nervosa, [[Anorexia Nervosa]])
    • Chemotherapy Patients
    • Homeless/Alcoholic Patients Who Have Not Eaten for Many Days (see Ethanol, [[Ethanol]])
    • Malnourished Elderly Patients (see Malnutrition, [[Malnutrition]])
    • Specific Post-Operative Patients
    • Any Other Patient Who Has Not Received Significant Nutrition for >5 Days

Other

  • Increased Risk of Clostridium Difficile Colitis (see Clostridium Difficile, [[Clostridium Difficile]])
    • Clinical Data
      • Hospitalized Patients Who Receive Tube Feedings are at Increased Risk for Clostridium Difficile, as Compared to Hospitalized Patients Who Do Not Receive Tube Feeding (Ann Intern Med, 1998) [MEDLINE]
  • Micronutrient Deficiencies

Pulmonary Complications/Adverse Effects

  • Aspiration (see Aspiration Pneumonia, [[Aspiration Pneumonia]])
    • Potential Preventative Measures: although it’s not clear that these measures actually decrease the risk of aspiration pneumonia (in particular, ventilator-associated pneumonia)
      • Elevation of the Head of the Bed
      • Percutaneous Gastrostomy (PEG) Tube Placement (see Gastrostomy, [[Gastrostomy]]): however, gastrostomy tubes have not been demonstrated to impact the rate of aspiration pneumonia or the mortality rate, as compared to nasogastric tubes (Cochrane Database Syst Rev, 2015) [MEDLINE]
      • Pro-Motility Agents to Enhance Gastric Emptying
      • Post-Pyloric Feeding

Renal Complications/Adverse Effects

  • Hypernatremia (see Hypernatremia, [[Hypernatremia]])
    • Physiology: most tube feedings contain only 70-80% water, are mildly hypertonic, and are not adequate to meet the patient’s normal water requirements
    • Treatment: most patients require additional free water to meet water requirements (and for flushing of the feeding tube itself)

Other Complications/Adverse Effects

  • Overfeeding: with increased carbon dioxide production
  • Underfeeding: with prolonged ICU stay

References

  • Intestinal obstruction from cecal bezoar; a complication of fiber-containing tube feedings. Nutrition. 1990;6(1):115 [MEDLINE]
  • Nutritional effect of continuous hemodiafiltration. Nutrition 1995; 11:388–393
  • Impact of the nutritional regimen on protein catabolism and nitrogen balance in patients with acute renal failure. JPEN J Parenter Enteral Nutr 1996; 20:56-62
  • Acquisition of Clostridium difficile and Clostridium difficile-associated diarrhea in hospitalized patients receiving tube feeding. Ann Intern Med. 1998;129(12):1012 [MEDLINE]
  • Prospective, randomized, controlled trial to determine the effect of early enhanced enteral nutrition on clinical outcome in mechanically ventilated patients suffering head injury. Crit Care Med. 1999;27:2525–2531 [MEDLINE]
  • Enteral nutrition-related gastrointestinal complications in critically ill patients: a multicenter study. The Nutritional and Metabolic Working Group of the Spanish Society of Intensive Care Medicine and Coronary Units. Crit Care Med. 1999;27(8):1447 [MEDLINE]
  • Enteral compared with parenteral nutrition: a meta-analysis. Am J Clin Nutr. 2001;74(4):534-542 [MEDLINE]
  • High protein intake during continuous hemodiafiltration: Impact on amino acids and ni-trogen balance. Int J Artif Organs 2002; 25:261–268
  • Prospective randomized trial to assess caloric and protein needs of critically Ill, anuric, ventilated patients requiring continuous renal replacement therapy. Nutrition 2003; 19:909–916
  • Early enteral nutrition in mechanically ventilated patients in the prone position. Crit Care Med. 2004 Jan;32(1):94-9 [MEDLINE]
  • Nutritional management of acute renal failure. J Ren Nutr 2005; 15:63–70
  • Does enteral nutrition compared to parenteral nutrition result in better outcomes in critically ill adult patients? A systematic review of the literature.
    Nutrition. 2004;20(10):843-848 [MEDLINE]
  • Metabolic and nutritional aspects of acute renal failure in critically ill patients requiring continuous renal replacement therapy. Nutr Clin Pract 2005; 20:176–191
  • Effects of different energy intakes on nitrogen balance in patients with acute renal failure: A pilot study. Nephrol Dial Transplant 2005; 20:1976–1980
  • ASPEN Guidelines on Enteral Nutrition: Adult renal failure. Clin Nutr 2006; 25: 295–310
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