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Enteral Nutrition In Critically Ill. Rasha S.Bondok M.D. Anaesthesia & Intensive Care Ain-Shams University. Enteral Nutrition. Terminology Enteral nutrition = Administration of nutrients via the existing GIT
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Enteral Nutrition In Critically Ill Rasha S.Bondok M.D. Anaesthesia & Intensive Care Ain-Shams University
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
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
Rationale for EN……. • Favours intestinal villous trophicity • Promotes gut motility • Reduces translocation of bacteria from gut • Less costly than PN
Why feed the critically ill patient?Metabolic changes occur in response to starvation, trauma and sepsis
Starvation & Trauma Skeletal muscle Amino Acids Liver Glucose Protein breakdown Amino acids Glucose Synthesis Lactate from tissues FFA Adipose tissue Glycerol Triglyceride Glycerol & FFA
Sepsis Skeletal muscle Amino Acids Liver Glucose Protein breakdown Glycogen Amino acids Glucose Synthesis Ketone Bodies Ketone Bodies Lactate from tissues FFA Adipose tissue Glycerol Triglyceride Glycerol & FFA
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 (>5% of usual body weight in 3 weeks or >10% in 6 months)
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
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) < 20 kg/m2
Clinical Markersof nutritional state • Clinical Markers of nutritional state: • Widely available, sensitive, easily reproducible, highly specific • Unfortunately---No such marker is available
Clinical Markers of nutritional state • Visceral protein parameters include: • 1-Albumin • 2-Transferrin • 3- Prealbumin. • Somatic protein parameters include: • Nitrogen balance studies
Clinical Markers of nutritional state …..Albumin • Normal level 3.5-5g/dL • 3-3.5g/dL—nutritional decision point • < 3.5g/dL--- poor surgical outcome prolonged ICU stay. • <3g/dL ---severe malnutrition. • <2.5g/dL---increased Mortality& Morbidity
…..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 ------ can’t effectively monitor acute response to nutrition therapy
Clinical Markers of nutritional state …..Transferrin • Short ½ life---8-9days • Normal levels 200-400mg/dL • Levels 150mg/dL—nutritional decision point • Factors level: e.g. Nephritic syndrome, burns, inflammation chronic infection
Clinical Markers of nutritional state …..Prealbumin • Short ½ life--- 2 days • Normal level 16-35mg/dL • Nutritionally significant level 11mg/dL • <11mg/dL = Malnutrition • Failure to increase above 11mg/dL–nutritional needs are not met • Factors level e.g. stress, inflammation, surgery, cirrhosis renal failure.
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.
Nitrogen Balance • If calculated nitrogen balance equals: 0 -- Nitrogen balance. >0 -- Protein anabolism > catabolism = +ve nitrogen balance -- Goal in nutritional repletion is +ve N2 balance of 4-6 grams per day. <0 -- Protein catabolism > anabolism = -ve nitrogen balance Catabolism: starvation, trauma, surgery, inadequate nutrition therapy
Nutrition risk index • Nutrition risk index= [1.519 x serum albumin (g/l) ]+ [0.417 x (current weight/usual weight x 100)] • >97.5 Borderline malnourished • 83.5 - 97.5 Mildly malnourished • < 83.5 Severely malnourished
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?
Nutrition risk index= [1.519 x 22] + [0.417 x {(58/69) x 100}] =68 Severely malnourished
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
Severe diarrhea • Protracted Vomiting Are Not Contraindications • Intestinal dysmotility
How much EN should critically ill patient receive? • During acute initial phase of illness—exogenous 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 Nutrition:Intensive care Clinical Nutrition (2006)
Quiz What length of small bowel is necessary to maintain adequate Enteral Nutritional Status?
Is early EN (< 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
Do Not Feed a Necrotic Bowel !! • INSTEAD FEED EARLY TO PREVENT A NECROTIC BOWEL
To prevent necrotic bowel • If EN is not tolerated, TPN is needed, • minimal enteral nutrition = Trophic Feeds < 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
Access For Enteral Nutrition • Administration Sites • Routes For Feeding Access
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 >100ml/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 Administration Site
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
Access Techniques…..cont Nasojejunal NJ tubes • Indicated—gastric 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
Access Techniques…..cont • Check tube position
Access Techniques…..cont • Long Term access > 4-6wk----Feeding Ostomies (Enterostomies) • Percutaneous Endoscopic Enterostomy • Surgical Enterostomy
Percutaneous Endoscopic Enterostomy 1- Percutaneous Endoscopic Gastrostomy PEG: Method of choice Considered in pat. with normal gastric emptying
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 91:136)
Feeding Ostomies (Enterostomies)Percutaneous Endoscopic Jejunostomy 2- PEJ • New— • Technically difficult • Indicated if postpyloric feeding is needed • Allows concomittent jejunal feeding and gastric decompression
Administration of EN • Bolus • Continuous • Intermittent • Cyclic
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: -Recommended for gastric feedings -Requires intact gag reflex -Normal gastric function
Initiation ofBolus 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
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
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
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
Don’t 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 manufact’s info • Subtract amount of free water from needs • Provide additional water via flushes
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
Enteral Feeding ToleranceGastric Residuals • RV--- routinely checked to assess: -Tube feeding tolerance and -Signify aspiration risk • Take into account flow of normal secretions from mouth to stomach = ≈ 2–3 L/d or 100–150 mL/hr • Clinically assess patient for abdominal distension, fullness, bloating, discomfort
If Gastric Residuals Limit Tube Feeding Delivery ? 1-Place patient on his right side for 15–20 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 <200mg% to avoid gastroparesis from hyperglycemia 6- Use narcotic alternatives
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
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.