Enteral Nutrition In Critically Ill

1
Enteral Nutrition In Critically Ill

• Rasha S.Bondok
• M.D.
• Anaesthesia Intensive Care
• Ain-Shams University

2
Enteral Nutrition

• Terminology
• Enteral nutrition Administration of nutrients
  via the existing GIT
• EN is confined to tube feeding exclusively
  without regards to oral nutritional supplement

3
When is EN indicated in ICU patients?

• IF THE GUT WORKS,
• USE IT OR LOOSE IT
• All patients with functioning gut who are not
  expected to be on a full oral diet within 3 days

4
Rationale for EN.

• Favours intestinal villous
• trophicity
• Promotes gut motility
• Reduces translocation of
• bacteria from gut
• Less costly than PN

5
Why feed the critically ill patient? Metabolic
changes occur in response to starvation, trauma
and sepsis
6
Starvation Trauma
Skeletal muscle
Amino Acids
Glucose
Liver
Protein breakdown
Amino acids
Glucose Synthesis
Lactate from tissues
FFA
Adipose tissue
Glycerol
Triglyceride
Glycerol FFA
7
Sepsis
Skeletal muscle
Amino Acids
Glucose
Liver
Protein breakdown
Glycogen
Amino acids
Glucose Synthesis
Ketone Bodies
Ketone Bodies
Lactate from tissues
FFA
Adipose tissue
Glycerol
Triglyceride
Glycerol FFA
8
Nutritional Assessment as the 1st step of EN

• Goal -Detection of prior malnutrition
• -Prevent/minimize further loss of
  BW
• 1. Patient history
• Disease states associated with heightened risk
  of malnutrition
• (e. g., chronic debilitating disease)
• Recent severe loss of weight (gt5 of usual body
  weight in 3 weeks or gt10 in 6 months)

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Nutritional Assessment..

• -Inadequate nutrition intake results from any of
  the following factors
• Orders for nothing by mouth (NPO) x 3 days
• Clear liquid diet x 5 days
• Malabsorptive disorder
• Impaired ability to ingest

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Nutritional Assessment..

• 2. Assessment of present condition
• Diseases associated with hypermetabolism and
  prolonged catabolic activity
• (Multiple injuries, Burns, persistent Fever,
  Sepsis, MOF)
• Signs of malnutrition on physical examination (e.
  g., cachexia, muscle atrophy, edema)
• Body Mass Index (BW in kg/height in m2)
• lt 20 kg/m2

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Clinical Markers of nutritional state

• Clinical Markers of nutritional state
• Widely available, sensitive, easily reproducible,
  highly specific
• Unfortunately---No such marker is available

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Clinical Markers of nutritional state

• Visceral protein parameters include
• 1-Albumin
• 2-Transferrin
• 3- Prealbumin.
• Somatic protein parameters include
• Nitrogen balance studies

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Clinical Markers of nutritional state ..Albumin

• Normal level 3.5-5g/dL
• 3-3.5g/dLnutritional decision point
• lt 3.5g/dL--- poor surgical outcome
• prolonged ICU stay.
• lt3g/dL ---severe malnutrition.
• lt2.5g/dL---increased Mortality Morbidity

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..Albumin

• Albumin levels are low ----acute phase response
• Low albumin level is an unreliable marker of
  malnutrition in the critically ill.
• ½ life is lengthy 21days ------ cant effectively
  monitor acute response to nutrition therapy

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Clinical Markers of nutritional state
..Transferrin

• Short ½ life---8-9days
• Normal levels 200-400mg/dL
• Levels 150mg/dLnutritional decision point
• Factors level
• e.g. Nephritic syndrome, burns, inflammation
  chronic infection

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Clinical Markers of nutritional state
..Prealbumin

• Short ½ life--- 2 days
• Normal level 16-35mg/dL
• Nutritionally significant level 11mg/dL
• lt11mg/dL Malnutrition
• Failure to increase above 11mg/dL nutritional
  needs are not met
• Factors level
• e.g. stress, inflammation, surgery, cirrhosis
  renal
  failure.

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Nitrogen Balance

• Measures UUN and compares it to nitrogen intake
  during that same time
• N2 balance N2 intake N2 excretion or
• 24h protein (g) 24 h UUN (g) 3(g)
• 6.25 g nitrogen
• "fudge factor" of 3 nitrogen losses in the
  faeces, skin, body fluids.

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Nitrogen Balance

• If calculated nitrogen balance equals
• 0 -- Nitrogen balance.
• gt0 -- Protein anabolism gt catabolism ve
  nitrogen balance
• -- Goal in nutritional repletion is ve N2
  balance
  of 4-6 grams per day.
• lt0 -- Protein catabolism gt anabolism -ve
  nitrogen balance
• Catabolism starvation, trauma,
  surgery, inadequate nutrition
  therapy

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Nutrition risk index

• Nutrition risk index
• 1.519 x serum albumin (g/l) 0.417 x (current
  weight/usual weight x 100)
• gt97.5 Borderline malnourished
• 83.5 - 97.5 Mildly malnourished
• lt 83.5 Severely malnourished

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• You are asked to see a 70-year-old man on his
  admission to ICU with oesophageal carcinoma . You
  note that his serum albumin level is 22g/l , his
  current weight is 58kg. On questioning he
  remembers that his usual weight was 69kg when he
  was well.
• Using the nutrition risk index how would you
  categorise his nutritional state?

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• Nutrition risk index
• 1.519 x 22 0.417 x (58/69) x 100
• 68
• Severely malnourished

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Contraindications of EN

• Intestinal Obstruction
• Anatomic Disruption.
• Intestinal Ischaemia/Perforation
• Inability to access the gut eg. severe burns
• Shock---reduced intestinal perfusion
• Unable to splanchnic blood flow in response to
  
• EN-----be cautious

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• Severe diarrhea
• Protracted Vomiting Are Not
  
  
  Contraindications
• Intestinal dysmotility

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How much EN should critically ill patient receive?

• During acute initial phase of illnessexogenous
  energy 20-25 Kcal/Kg/day
• Excess is detrimental
• During recovery phase ---30-40 Kcal/Kg/day
• Protien intake should be 1.2-1.5 g/Kg/day never
  exceeding 1.8 g/Kg/day Except ---extreme losses
  burns, digestive losses
• ESPEN Guidelines on Enteral
  NutritionIntensive care Clinical Nutrition
  (2006)

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Quiz

• What length of small bowel
• is necessary to maintain
• adequate Enteral Nutritional
• Status?

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Is early EN (lt 24-48hr) superior to delayed EN in
critical ill?

• Critical ill who are haemodynamically stable
  functioning gut SHOULD be fed early if possible.
• Early EN------Reduction of infection.
• ------Reduction in hospital
  stay.
• Early EN 12-24 hours post trauma/burn
• Reduced morbidity
• In 5 studies not 1 case of bowel
  infarct/ischemia in early enterally fed

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Do Not Feed a Necrotic Bowel !!

• INSTEAD FEED EARLY TO PREVENT A NECROTIC BOWEL

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To prevent necrotic bowel

• If EN is not tolerated, TPN is needed,
• minimal enteral nutrition Trophic Feeds
• lt 25 of the calories provided by enteral route
  
• stimulate or maintain gut function
  decrease the chances of cholestasis.
• Continuous infusion 10-15 ml/h
• Bolus 6 x 50 ml/24

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Access For Enteral Nutrition

• Administration Sites
• Routes For Feeding Access

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Administration Site

• Gastric
• Normal reservoir for food
• Formula osmolality is less of a problem
• Gastric dysfunction paresis/atony precludes
  feeding in the stomach
• Diabetes
• Drugs (Sympathomimetics,
• Opiates,Dopamine)
• Hyperglycemia - ICP
• Surgery Trauma atony
• for 1-2 days but small bowel
• motility is normal

• Postpyloric
• Sensitive to volume
• Rates gt100ml/hr are not recommended
• Use isotonic formula
• Recommended in patients at risk of aspiration
• Impaired gag cough reflex
• Mechanically Vent
• Neurological injury
• Delayed gastric emptying

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Route For Feeding Access

• Short Term access (for 4-6wk)---
• Use Nasal Access naso-gastric/jejunal tubes
• Nasogastric tubes
• Allow use of hypertonic feeds
• higher feeding rates
• bolus/Intermittent feeding
• Fine bore 8-10 F NG tubes

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Access Techniques..cont

• Nasojejunal NJ tubes
• Indicatedgastric reflux
• --delayed gastric emptying
• --unconcious patient
• Fine bore 6-10 F
• Insertion same as NG, but once reached stomach,
  patient is turned onto the right side advance
  tube 10cm
• To assist postpyloric placement of NJ tube
• 10mg Metoclopramide iv 10 min 200mg
  Erythromycin iv 30min prior placement

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Access Techniques..cont

• Check tube position

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Access Techniques..cont

• Long Term access gt 4-6wk----Feeding Ostomies
  (Enterostomies)
• Percutaneous Endoscopic Enterostomy
• Surgical Enterostomy

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Percutaneous Endoscopic Enterostomy

• 1- Percutaneous Endoscopic Gastrostomy
• PEG Method of choice
• Considered in pat. with normal gastric emptying

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Percutaneous Endoscopic Gastrostomy

• Contraindications
• Gastric cancer
• Gastric ulcer
• Ascitis
• Coagulation disorders

(Source Kudsk KA, Jacobs DO. Nutrition. In
Surgery Basic Science and Clinical Medicine.
Norton JA, et al., eds. New York
Springer-Verlag, 2001(2) Part 7, Section 91136)
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Feeding Ostomies (Enterostomies) Percutaneous
Endoscopic Jejunostomy

• 2- PEJ
• New
• Technically difficult
• Indicated if postpyloric feeding is needed
• Allows concomittent jejunal feeding and gastric
  decompression

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Administration of EN

• Bolus
• Continuous
• Intermittent
• Cyclic

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Bolus Feedings
Administer 200-400 ml of enteral formula into the
stomach over 5 to 20 minutes, usually by gravity
with a large-bore syringe Indications -Recommende
d for gastric feedings -Requires intact gag
reflex -Normal gastric function
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Initiation of Bolus Feedings

• Initiate with full strength formula
• 3-8 times per day with increases of 60-120 ml
  q 8-12 hours as tolerated up to goal volume does
  not require dilution unless necessary to meet
  fluid requirements
• ASPEN Nutrition Support Practice Manual, 2005

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Continuous Feedings

• Administration into the GIT via pump or gravity,
  usually over 8 to 24 hours per day
• Indications
• Promote tolerance
• Compromised gastric function
• Feeding into small bowel
• Intolerance to other feeding techniques

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Initiation of Continuous Feedings

• Initiate at full strength at 10-40 ml/hour and
  advance to goal rate in increments of 10 to 20
  mL/hour q 8-12 hours as tolerated
• ASPEN Nutrition Support Practice Manual, 2005

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Intermittent Feedings

• Administration of 200-300 ml over 30-60 minutes
  q 4-6 hours
• Indications
• Intolerance to bolus administration
• Initiation of support without pump

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Dont forget to water your enteral feeding
patients!

• Water in Enteral Products
• Calculate free water
• 1kcal/ml 85 free water (850mL per 1,000 mL
  formula)
• 1.2-1.5 kcal/mL 69 - 82 (690-820)
• 1.5-2.0 kcal/mL 69 - 72 (690-720)
• Exact water content on label or in manufacts
  info

• Subtract amount of free water from needs
• Provide additional water via flushes

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Meeting Fluid Needs in Enterally-Fed Patients

• Water Flushes
• For Continuous feeds-- Irrigate tube q
• 4 hrs with 20-60 mL water
• For Intermittent / bolus feed--- Irrigate tubes
  before and after each feed with 20-60 mL water
• Use smaller vol for fluid-restricted pts

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Enteral Feeding Tolerance Gastric Residuals

• RV--- routinely checked to assess
• -Tube feeding tolerance and
• -Signify aspiration risk
• Take into account flow of normal secretions from
  mouth to stomach
• 23 L/d or 100150 mL/hr
• Clinically assess patient for abdominal
  distension, fullness, bloating, discomfort

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If Gastric Residuals Limit Tube Feeding Delivery ?

• 1-Place patient on his right side for 1520
  minutes before checking RV to avoid the cascade
  effect
• 2- Seek transpyloric access of feeding tube
• 3- Try using a prokinetic agent
• 4- Switch to a calorically dense product to
  decrease total volume needed
• 5- Tighten glucose control to lt200mg to avoid
  gastroparesis from hyperglycemia
• 6- Use narcotic alternatives

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Enteral Nutrition Diets
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Enteral Nutrition Diets

• 1-Polymeric Formula
• Nitrogen source whole protien
• CHO source oligosaccharides-starch
• Fat source vegetable oil.
• Minerals,vitamins,trace elements ---RDA
• A Standardized formulation provides
• 15-20 Pt, 30-40 Fat, 45-60 CHO
• Require some degree of digestion absorption
• Isotonic ------ Caloric density 1Kcal/ml

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Enteral Nutrition Diets

• 2-Elemental (Monomeric Oligomeric Formula)
• Chemically defined formulation
• Nitrogen source di/tripeptides, free a.a
• Can be absorbed by active transport without
  intraluminal hydrolysis
• CHO source Oligosaccharides-glucose
• Fat source Medium Chain Triglycerides, essential
  FA
• Indicated --- Limited Digestive Capacity
• intestinal fistula, radiation enteritis, short
  bowel syndrome.

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Enteral Nutrition Diets

• Elemental Formula
• Are Fiber Free
• Due to multiple small particles, it is highly
  osmotic 500-900 mOsm/L
• Therefore ---Osmotic diarrhea
• No advantage in using elemental diet in pat with
  normal GIT

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3-Special Formulas
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1-Hepatic Failure Formulas

• Decompensated Cirrhosis/Hepatic encephalopathy
  Conc of AAA are and BCAA are .
• This imbalance ---- hepatic encephalopathy by
  producing false neurotransmitters
• BCAA-enriched and AAA-deficient nutrition formula
  ------- 45-50 protien (BCAA)
• BCAA inhibit AAA from crossing BBB to
• act as false neurotransmitters

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2-Renal Failure Formulas

• CRF----- limited ability to excrete urea and
  electrolytes
• Essential AA formula To use urea for production
  of nonessential a.a -----reducing urea waste
• Hyperammonemia is a risk
• Polymeric Renal formula low in protein (to limit
  urea production) K Mg - P
• Indicated for CRF who are not receiving dialysis

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3-Pulmonary Formulas

• Metabolism of a calorie of CHO produces more CO2
  than the metabolism of a calorie of fat
• Low CHO --- CO2 load
• Modified CHOFat ratio , 40-55 calories are
  provided by fat.
• High fat feeds-----Delayed Gastric Emptying--Abd
  Distention----affect Diaphragmatic movement
  Thoracic expansion

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4-Gastrointestinal dysfunction Formulas

• Gut recovery may be accelerated by
  supplementation of glutamine and soluble fiber--a
  precursor SCFA.
• Glutamine and SCFA are metabolic fuels
• of enterocytes and colonocytes

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5- Metabolic Stress (Critical Care) Formula

• Provides exogenous source of BCAA-----Preferred
  energy source for muscle during critical illness
• Not equivalent to Hepatic Failure formula
• High protein not reduced in AAA content
• Not Given For Hepatic Failure

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5-Immunomodulatory (immune enhancing) Formulas
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5-Immunomodulatory (immune enhancing) Formulas

• Formulas---- Alter Bodys Response To
  Critical Illness
• Modify the inflammatory response
• Enhance resistance to infection wound healing
• Alteration include
• Enrichment with specific a.a Glutamine/Arginine
• Addition of Nucleotides
• Manipulation of FA content (n-6 to n-3 FA ratio)

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Glutamine

• Conditionally essential a.a.
• Primary Oxidative fuel for rapidly dividing cells
  -----Enterocytes- Lymphocytes- Macrophages
• proliferation of T-cells formation of ILs
• Precursor of GlutathionePotent Antioxidant
• A substrate for DNA and RNA synthesis
• Maintains normal intestinal integrity

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Glutamine

• Content in polymeric formula lt 14 of total
  protein
• Optimum Provision is 20-30g/day to meet basal
  GIT requirements in Critical Illness.
• Should be added to standard formula in
• Burned Trauma Patient Grade A recomend
• Contraindicated in Liver Failure/Encephalopathy
• ESPEN guidelines on Enteral nutrition 2007

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Arginine

• Conditionally EAA
• Synthesis occurs --- Intestinal-Renal axis
• Epith cells of SI-produce Citrulline from
  Glutamine
• Plays important role
• -Cell division (improves immune cell no. func)
• -Healing of wounds
• -Ammonia detoxification
• -Important secretagogue for insulin, glucagon, GH

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Arginine

• Nitric Oxide donor to GI tract
• Necessary for normal immune function
• Helps kills bacteria/parasites
• Nitric Oxide can be detrimental
• Mediates VDory effects of endotoxins------Contr
  oversy in cases of Septic Shock!!

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What are the major problems associated with tube
feeding?
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1- Aspiration----Most Important

• Prevalence range from 2 - 95
• Several issues should be considered
• 1-Tube Size and Position
• Large bore vs small bore
• Gastric vs Jejunal
• 2-Body Position Supine vs Semi recumbent
• 3-Underlying Disease Gastroparesis/ Atony
• 4-Feeding Regimen
• Intermittent or Continuous vs Bolus

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To Limit the Risk of Aspiration

• 1- Raise head of bed 30-400 during feeding and 1
  hr after
• 2-Use intermittent / continuous feeding regimens
  rather than------ bolus method
• 3-Check gastric residual regularly
• 4-Consider jejunal access--------
• -recurrent tube feeding aspiration
• -high risk of gastric motility dysfunction

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2-Diarrhea----Most Common

• Incidence 2.3 - 68
• Critically ill are more prone
• Multiple aetiologies
• 1-Medications
• Antibiotics-----overgrowth of C.difficile /
  Candida
• Sorbitol base liquids---Theophylline
• Meds containing Magnesium
• 2-Altered bacterial flora
• H2-blockers/ PPI---permit bacterial overgrowth
• Bacteria colonize---Gastric pH exceeds 4

68
2-Diarrhea----Most Common

• 3-Formula Composition
• Osmolality Rate
• incidence of diarrhea in critically ill
• mechanically vent patients----receiving
  hyperosmolar feeds at high infusion rates

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2-Diarrhea----Most Common

• 4-Hypoalbuminemia
• ---Reduces osmotic pr causes intestinal mucosal
  oedema
• Critically ill with s.Alb lt 2.6g/dl
  diarrhea with standard EN
• 5-Formula Contamination

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Altered Drug absorption Metabolism

• Phenytoin
• Binds to NG tubing at pH of enteral
• formulation----less drug delivery
• Warfarin
• Resistance 2ndry to Vit K in Enteral feedings
• Stop enteral feeding 2 hrs before and 2 hrs after

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Metabolic Complications

• Less frequent compared to TPN
• Hyperglycemia 2ndry to High CHO load in specific
  formula esp critically ill / elderly--------insuli
  n resistance
• Electrolyte imbalance
• Use of high osmolar formulation esp Pat on fluid
  restriction/ renal concentrating difficulties are
  at risk of
• -----Dehydration Hypernatremia

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Mechanical Complications

• Tube clogging
• First line is to instill warm water using slight
  manual pressure.
• If fails, Pancreatic enzyme tablet crushed with
  Na HCO3 tablet dissolved in 5ml of water in
  order to "digest" the clog

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• Thank you