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In critically ill patient’s, malnutrition is associated with impaired immune function, impaired ventilator drive and weakened respiratory muscles leading to ventilator dependence and increased infectious morbidity and mortality. Malnutrition is prevalent in ICU patients, has been reported as being as high as 40% on admission, and is associated with poor patient’s outcomes such as in:

  1. Non-surgical based patients – increase metabolic requirement by disease process
  2. Surgical patients – inadequate nutritional intake, surgical stress and the subsequent post-operative increase in metabolic rate.

ESPEN Guidelines 2010, suggested to feeding as soon as after initial resuscitation or within 24-48 hours of admission. The benefits of nutrition support include:

  1. Improved wound healing
  2. Decreased catabolic response to injury
  3. Improved gastrointestinal structure and function
  4. Improved clinical outcomes including a reduction in complication rates and length of stay with accompanying cost savings
  5. Stress ulcer prophylaxis

Early EN can be associated high gastric residuals, bacterial colonization of the stomach, and an increased risk of aspiration pneumonia.  Parenteral nutrition has been associated with gut mucosal atrophy, overfeeding, hyperglycemia, an increased risk of infectious complication and increased mortality.

Despite the potential risks of EN, it is the preferred route to deliver nutrition support to the critically ill adult. The following guidelines were developed to help ensure timely, safe, cost-effective EN.



Early Enteral Nutrition is encouraged for the following patient populations:


  1. Multisystem Trauma
  1. Patients anticipated requiring > 48 hrs of mechanical ventilation.
  2. Non-intubated patients with altered mental status or closed head injury that precludes oral intake.
  3. Patient's with an open abdomen should not receive enteral feeds until confirmation otherwise from primary surgical team



  1. Burn Patients
  1. Adults (15-59 years of age) with > 19% Total Body Surface Area (TBSA) burns.
  2. Adults >59years of age with >14% TBSA
  3. Pediatric (under 15 years of age) with >14% TBSA
  4. Intubated patients anticipated to require > 48 hours of mechanical ventilation.



  1. Surgical/Neurology/Neurosurgery Patients
  1. All necrotizing fasciitis patients admitted to the ICU.
  2. Patients anticipated being Nil by Mouth (NBM) more than 5 days or with severe malnutrition on admission.
  3. Pre-operative patients with malnutrition and altered mental status.
  4. All patients less than 15 years of age should be carefully evaluated for the need for early nutrition support
  1. Medical ICU Patients

All patients receive enteral feeds <48 hours after admission with exception of the following:

  1. Expected to be NBM less than 3 days.
  2. Acute pancreatitis unless decision is made for feeding by surgeon.
  3. Ongoing Gastro-intestine (GI) bleeding.
  4. Bowel obstruction or ileus.
  5. Need for continued NBM status due to procedures.
  1. Medical Wards
  1. Patients expected to be NBM for any reason for more than 5 days unless they have a contraindication to enteral feedings such as those above.
  2. Special attention paid to patients who are nutritionally compromised at admission (cachexia, albumin<25mg/dL, End-Stage Liver Disease, End-Stage Renal Disease, Human Immunodeficiency Virus, chronic infection, etc.).



  1. Categories of Enteral Formulas




Standard Intact Nutrients

Whole protein nitrogen source, for use in patients with normal or near normal GI function; Most products contain ~ 1.0 kcal/ml; Protein content varies; Most are lactose-free; Products are fiber containing or fiber-free


Predigested nutrients; most have a low fat content or a high percentage of medium chain triglycerides; for use in patients with severely impaired GI absorption

Fluid Restricted

Intact nutrients, calorically dense (2.0 kcal/ml)


Intact nutrients, calorically dense (2.0 kcal/ml), low phosphorus and low potassium

Other disease specific

Intact nutrients designed for feeding patients with respiratory disease, diabetes, hepatic failure and immune compromise. Well-designed clinical trials may or may not be available to support use




  1. Types of feeding tubes
  1. Nasogastric / Orogastric
  2. Nasoduodenal / Nasojejunal
  3. Percutaneous Endoscopic Gastrostomy (PEG)
  4. Percutaneous Endoscopic Jejunostomy (PEJ)

Short Term Access: Anticipated need for enteral feeding < 6-8 weeks

  1. a) Nasogastric / Orogastric
  • Most common first line route.
  • Easy to place at bedside by nursing staff.
  • Use small flexible tubes to avoid nasal skin erosion.
  • Check position via auscultation/aspiration of gastric contents and gastric PH, as per nursing protocol. If in doubt regarding position by auscultation and aspiration then confirm with abdominal X-ray.
  • Literature review suggests no significant difference in pulmonary aspiration between gastric and post-pyloric feeding for patients with normal gastric motility.
  • Check residuals to evaluate tolerance.


*Keep head of bed should be elevated at 30-45° at all times unless contraindicated as a standard aspiration precautions. If this is not feasible, the head of the bed should be elevated as much as possible.

b)  Nasoduodenal / Nasojejunal
  • Used for patients who do not tolerate gastric feeds or patients with known abnormality of gastric emptying.
  • Can attempt to place at bedside and check X-ray for migration past the pyloric.
  • Residuals not helpful if tube remains post-pyloric, watch for signs of abdominal pain or distension to determine tolerance. Avoid starting feeds until patient is hemodynamically stable and initial volume resuscitation is complete.


*Caution: Patients with nasal obstruction or severe facial fractures should have these tubes placed orally.


Long Term Access (anticipated need for enteral feeding > 6-8 weeks)



  1. c) Percutaneous Endoscopic Gastrostomy (PEG)
  • Post-placement may start enteral feeds between 6 and 24 hours. Keep tube clamped until able to start enteral feeds. Recent studies support early enteral feeding with PEG tubes (6-12 hrs), however, many providers continue to support a 24 hour period of gravity drainage prior to feeding.
  • The tube should also be secured to the skin with tape to avoid traction on the tube leading to dislodgment.
  • Care of site: Soap and water, Gauze over tube and tape securely for 24 hours.


  1. e) Percutaneous Endoscopic Jejunostomy (PEJ)
  • Usually placed in conjunction with a laparotomy or for patient who need long term enteral access and cannot tolerate gastric feeds.
  • Laparoscopically placed tubes will have suture bolsters around the skin exit site. These should not be manipulated by anyone other than the surgeon.
  • Enteral feeds can begin 12 hours after surgery.



  • Needle catheter jejunostomy tubes are much smaller diameter than standard tubes and are thus much more likely to obstruct. They must be flushed frequently and high fiber formula and medications should not be administered through these tubes.
  1. All tubes not being used for continuous enteral feeds should be flushed with 30ml (adults) or 5-10 ml (pediatric) water every 4 hrs to ensure patency.


  1. Feeding Tube Obstruction


  1. Causes of Clogged Feeding Tubes
  1. Improper flushing of tubes.
  2. Caloric dense formulations.
  3. Small bore feeding tubes.
  4. Rate of flow that could allow gastric pH to clump the formula as well as cause a build up on the sides of the feeding tube.
  5. While evaluating gastric residuals the low pH can cause formula coagulation.
  6. Medications that are not properly crushed.


  1. Solutions
  1. Prevention:


  • Frequent flushing with water is the easiest way to prevent clogging.
  • Tubes should be flushed with 30 - 50 ml (adults) or 10ml (pediatrics) of water every 4-6 hours as a routine process as well as flushing pre and post medications can prevent most clogged feeding tubes.
  • Flushing pre and post gastric residual checks can also prevent the gastric acid accumulation and henceforth formula coagulation.
  1. Medications:
  • Use liquid medications whenever possible.
  • Some medications can be crushed after consultation with pharmacy.
  • Do not mixed medication with the formula.


  1. Small bore jejunostomy feeding tube clog very easily. Clarify medication administration guidelines from physician before using these tubes for medication administration.
  1. Unclogging: Here are several options:


  • Use 30 - 60 ml syringe, avoid small syringes due to high pressure.
  • Flush with warm water.
  • If these attempts to unclog the tube fail then the tube must



  1. Rate of Administration


Gastric Feeding


(i) Continuous Feeding


  1. Standard formulas should be started at a rate of 20-40ml/hr unless there is significant concern regarding gastric motility. Aspirate the feeding tube every 4-6 hours as to check feeding toleration.
  2. If aspirate < 200ml, return all aspirate. Increased feeding rate by 20-40ml/hr every 4-8 hours until the goal rate is met. Once target caloric needs are met, the feeds may be further diluted with water to meet the fluid requirements of the patient.
  3. Elemental formulas should start at full strength at 20-30ml/hr for the first 12 hours then advance by 20-30ml/hr every 6-12 hours until reaching goal rate.
  4. 2kcal/ml formulas should be started at 10-20ml/hr and advanced by 10-20ml/hr every 6-12 hours until reaching goal rate even if the patient has been on a standard formula prior to this formula change.
  5. If aspirate >200ml, return 200ml aspirate to patient and hold feeding for 4-8hours. Re-check gastric aspiration, if nil or less than 30ml, re-start feeding again. Exclude bowel obstruction first. If there is no clinical evidence of bowel obstruction, administer prokinetic agents.

(ii) Bolus Feeding


  1. Start with 30-50ml every 3-4 hours. Aspirate before every feed.
  2. If aspirate < 200ml return aspirate to patient. Increase by 25-50ml after every 2-4 feeds until calorie needs are met. Once target calorie needs are met, the feeds may be further diluted with water to meet the fluid requirements of the patient.
  3. If aspirate >200ml, return 200ml aspirate to patient and reduce by 50% of current feeding. Exclude bowel obstruction first. If there is no clinical evidence of bowel obstruction, administer prokinetic agents.


(iii) Jejunal or Duodenal Feeding

  1. Standard or elemental feedings at full strength at 20-30 ml/hr for the first 12 hours then advance by 20-30ml/hr every 6-12 hrs until reaching goal rate.
  2. Continuous feeding method is recommended.

Types of enteral feeds





* Suggested Maximum Volume/Day


- Ensure

- Osmolite

- Enercal

- Isocal

- Nutren

- Pediasure

- Nutren Junior


- Most patients

C : 60-80 ml/hr

B : 200-250 ml 3-4H


- Jevity

- Nutren fiber

1 kcal/ml

- Diarrhea

- Fiber containing feeds

C : 60-80 ml/hr

B : 200-250 ml 3-4H


- Glucerna

- Glucerna SR

- Nutren diabetic


- Diabetic patients

- Stress induced hyperglycemia

C : 60-80 ml/hr

B : 200-250 ml 3-4H

- Nepro

2 kcal/ml

- Renal failure with fluid

  restriction and on dialysis

C : 30-40 ml/hr

B : 100-120 ml 3-4H

- Pulmocare

1.5 kcal/ml

- Patients with

  hypercapnia (eg COAD)

C : 50-60 ml /hr

B : 150-200 ml 3-4H


- Peptamen

- Peptamen Junior

1 kcal/ml

- Patients with gastrointestinal

  problems (pancreatitis,

  short bowel syndrome)

C : 60-80 ml/hr

B : 200-250 ml 3-4H


C = Continuous, B = Bolus

*Please note that the suggested maximum volume is not restricted to the examples given. It is important that the target caloric needs are eventually met in whatever volume that is delivered to the patient. If the patient has increased fluid requirements, supplemental fluids may be given as diluted feeds (the maximum flow rates can be increased) or given intravenously.



  1. Pediasure, Nutren Junior and Peptamen Junior normally used for paediatric for High Calorie High Protein Diet but also can be used for adults who needs protein restriction with good urine output (>0.5ml/kg/day).
  2. Nutrient mixtures prepared in the kitchen (“blended diet”) should not be used as this type of feed is unbalanced, causes feeding tube occlusion and diarrhea secondary to bacterial contamination except for oral transition feeding.

Pediatrics (Gastric Feeding):


(i)  Continuous / Infusion Feeding:

  1. Initiation of feeding: 1-2ml/kg/hr

      If the patient has been NBM for several days initiate the feeding more slowly.

  1. If tolerated increase 1-2ml/kg/hr every 6-8 hrs to goal rate until met.
  2. Gastric Residual evaluation:
  1. If residuals are greater than the previous hour's feeding volume this is considered a significant volume. Hold tube feeds for one hour. If patient continues to have a high residual, use of a prokinetic agent should be considered. Consider post-pyloric feeding tube placement if necessary.

(ii) Bolus Feeding:


  1. Initiation of feeding rate with 5-15ml every 3 hours. Aspirate before every feed.

      If the patient has been NBM for several days initiate the feeding more slowly.

  1. If tolerated after 2-3 times of feeding, increase feeding rate 5-15 ml each until met goal rate.
  2. Gastric Residual evaluation:
  • If residuals are greater than the previous hour's feeding volume this is considered a significant volume. Hold tube feeds for one hour. Re-check gastric aspiration, if allow by physician, re-start feeding again.
  • If patient continues to have a high residual, use of a prokinetic agent should be considered. Consider continuous feeding if necessary.
  1. When to Hold Enteral Feeding


  1. ½ hour prior to procedures requiring the Trendelenberg position which the body is laid flat on the back (supine position) with the feet higher than the head.
  1. 6 hours prior to general anesthesia for non-intubated patients.
  1. Intubated patients having either airway surgery (includes tracheostomy) or planned re-intubation (such as thoracotomy / thoracoscopy), patient should be NBM a minimum of 6 hours.
  2. Intubated patients having planned surgery on the GI tract, NBM from Midnight.
  3. All other intubated patients, enteral feeds can be continued until the time of departure to the operating room. This includes any patient who will be prone during surgery or extubated post-operatively.



1. Monitoring tolerance

  1. Gastric feeds

-     Check gastric residual volumes as recommended above.

  • Hold tube feedings for residuals greater than 200ml.
  • Re-infuse the residual and recheck as recommended above.

-     Feeds should also be hold for increasing abdominal distension and/or emesis.

  1. Jejunal feeds

-     Residual volumes are not helpful.

  • Monitor abdomen for distension and bowel sounds every 4-8 hours.
  • Hold feeds for emesis, abdominal pain or distension.
  1. GI Complications Associated with Enteral Feedings (Adults):







1-4+ times/12 hrs

- Place NG to suction

- Check NG function.

- Check existing NG function.

- Reduce TF infusion rate by 50%

Abdominal Distension and/or cramping or tenderness

(if detectable)


History and/or physical evidence

- Check for constipation

- Maintain TF infusion rate

- Re-examine in 6 hours

- If indicators remain mild, maintain TF infusion rate


History and/or physical evidence

- Abdominal X-rays to assess for small bowel obstruction.

- Stop TF infusion.

- Replace existing NG Catheter


>24 hr or Severe

History and/or physical evidence

- Stop TF infusion.

- Consider TPN.



1-2 x per day or 100-200ml/12 hrs

- Maintain TF infusion rate.

- Evaluate for pharmaceutical causes. Increase to goal.


3-4 x per day or 200-300ml/12 hrs

- Maintain TF infusion rate.

- Re-examine in 6 hours.

- If mild or moderate, continue to goal rate

- Evaluate medications


>4 x per day or >300ml/12 hrs

- Reduce TF infusion rate by 50%.

- Request Stool Studies

- Evaluate medications.

NG = Nasogatric, TF = Tube Feeding





High NG output with post-pyloric Feeding Tube Placement


NG output > 800cc (with post-pyloric FT placement)

- Hold tube feedings

- Notify primary team

- Check X-ray to verify post-pyloric feeding tube placement

High Gastric Residuals with gastric Feeding Tube placement


Hold tube feedings for residuals greater than 200cc

- Notify primary team

- Start prokinetic agent

- Head of bed elevated 30 degrees when possible

- Check for constipation



Less than 2 bowel movements per week

- Stool softeners and water boluses per primary team;

NG = Nasogatric, FT = Feeding Tube

  1. Possible Metabolic Complications of Enteral Feedings

Possible Etiology

Possible Causes

Possible Treatment


Excessive free water, abnormal sodium loss

Change to Fluid restricted formula, discontinue water boluses/IVF, replace sodium losses


Inadequate hydration, increased fluid losses, Diabetes Insipidus

Add or increase water boluses

or IVF


Anabolism/re-feeding, diuretics/medications

Supplement potassium


Renal Failure, metabolic acidosis, catabolism, GI bleed, Acute dehydration

Correct imbalance, Change to renal formula as appropriate



Supplement phosphorus


Renal failure

Change to renal formula, phosphate binders if necessary


Anabolism/re-feeding, diuretics/medications

Supplement magnesium


Diabetes, steroid therapy, Sepsis, Trauma, Pancreatitis

Insulin drip per protocol. Goal is to maintain blood glucose at


IVF = Intra Venous Fluids



  1. Feed termination
  1. Following extubation Enteral Nutrition (EN) should be resumed in a timely manner (i.e. within 2-4 hours of extubation unless contraindicated). The ability of the patient to resume oral intake should be assessed in a timely manner (i.e. 4-8 hours following extubation). Contraindications to oral intake include a reduced level of consciousness, the presence of dysphagia, etc. 
  2. EN should be terminated when oral intake is able to provide >75% of the patient’s daily energy requirement.