Enteral and Parenteral Nutrition PDF

UNIT 4 MEDIC NUTWTTION THE Y IN CRHTICAL C Structure 4.1 Introduction 4.2 Nutritional Management of the Critically Ill 4.3 Special Feeding Methods in Nutritional Support 4.3.1 Enteral Nutrition 4.3.2 Parenteral Nutrition 4.4 Let Us...

UNIT 4 MEDIC NUTWTTION THE Y IN CRHTICAL C Structure 4.1 Introduction 4.2 Nutritional Management of the Critically Ill 4.3 Special Feeding Methods in Nutritional Support 4.3.1 Enteral Nutrition 4.3.2 Parenteral Nutrition 4.4 Let Us Sum Up 4.5 Glossary 4.6 Answers to Check Your Progress Exercises Tlle prevalence of malilutrition is a colnmon problem in critically ill patienls i.e. patients who have prolonged starvation for more than 2 weeks or intensivc care unit (ICU) patients, or hospitalized patients with malnutrition. Malnutrition, we know, leads to poor outcomes and therefore should be avoided or treated promptly. In this context, nutritional support has become a routine part of the care of critically ill patients and it is now widely accepted for the treatment and prevention of malnutrition and other specific conditioils of nutrient deficiencies. There is growing evidence that early and appropriate goal oriented nutritional support in the ill individual aids recovery. What is the nutritional support recommended for the critically ill patients? What is the principle and protocol for prescribing these nutritional supports? Thesc are a few issues highlighted in this unit. Objectives After studying this unit you will be able to: e describe the nutritional management of critically ill individuals, e enumerate the special feeding methods for nutritional support to the critically ill individuals, and e explain the principle and protocol for prescribing these nutritional support. 4.2 NUTRImONAL GEMENT OF THE GRITIGALLUILL Evidence suggest that critically ill patients or hospitalized patients with malnutrition (macronutrient an;l/or micronutrient deficiency) suffer from increased infectious morbidity, prolonged hospital stays, and increased mortality. Moreover, even those hospitalizcd medical and surgical patients without antecedent malnutrition are typicalIy subjected to stress, infection and impaired organ function, resulting in a hypercatabolic state. Often these patients are unable to meet their caloric needs, as they are either too sick or physically unable to ingest food. In fact, critically ill patients present with extreme degrees of metabolic disarrangement in protein and energy metabolism characterized by increased protein breakdown which is not entirely suppressed by protein or energy intake. In addition there are also extreme degrees of glucose and lipid intolerance. Thus providing adequate and optimal nutrition support to the critically ill under these conditions constitute a challenging endeavour. Nutritional support has Clinical Therapeutic become a routine part of the care of critically ill patient and is now widely accepted Nutrition for treatment and prevention of malnutrition and specific nutrient deficiencies. The main goal of nutrition support is to provide an optimum amount of nutritents and calories to prevent malnutrition from becoming the main cause for morbidity and mortality in the disease process. The other goals of nutrition support include: e improve nutritional assessment indices, o prevent single and multiple nutrient deficiencies, o promote organ integrity and function, o ameliorate clinical manifestations of the disease, e favourably affect the disease process, and o positively influence the patient outcome. In fact, what proportion of the nutrients to be delivered to critically ill has been debated for years now. Interestingly, earlier concepts in critical care nutrition has u~ldergoi~e considerable changes in the past decade or so. For example, few years ago, 50- 70 Kcal/kg per day was routinely being delivered during critical illness and curreiitly, a pragmatic approach is to attempt administration of 25 kilocalories per kilogrnnz ideal body weight per day for most patients. The total calorie daily requirement should be administered in a fluid volume consisteilt with thc patient's needs (usually 1 ml/Kcal). Protein sources should comprise 15-20% of thc total claily calorie requirement administered as protein or amino acid depending on the route of administration. The generally accepted amount of protein is between 1.2 and 1.5 g/kg per day, except in severe losses such as burns. 30-70%of the total calories can be given as carbolzydrate. This is usually given as glucose but fructose and sorbitoi can also be used. Insulin may be required to maintain blood glucose concentration within normal limits, especially since insulin resistance is often seen as part of the response to stress. 15-30% of the total calories can be given as fat. Critically ill patients often utilize fat better than carbohydrates as an energy source and although our normal diets contain around 30%fat, it is often advantageous to provide more than this to the patients in ICU (Intensive Care Unit) or in IlDU (High Dependency Unit). at least 7% of total calories should be provided as Omega-6-polyunsaturated fatty acids (PUPA) and triglycerides to prevent essential fatty acid deficiency. Regarding micronutrient requirements, approximately lmmol/kg of botli sodium and potassium are usually given but this figure will need to be altered when there are excessive losses, particularly common from excess sweating and gastrointestina1 Iosses. An often forgotten electrolyte is phosphate and this is important since it is required for normal metaboIic processes resulting in the formatioil of ATP. Other micronutrients, e.g, magnesium, iron, copper, zinc and selenium are also necessary, but in much smaller amounts. Fat soluble vitamins (vitamin A, carotene) and water- solubIe vitamins are also important, but the precise requirement for specific vitamins remain unclear. Further, there is emerging data that increased antioxidant vitamins (vitamin A, E, C) may be beneficial in various high risk populations in ICU. The Harris-Beltedict equation can be used to calculate resting energy expenditure (REE), for men and women, along with the usual multiplication !actor to provide adequate calorie intake as given herewith: Calorie requirements/duy: 1.25 x REE (for each 1°C above 37 add 10% extra allowance) Women REE = 655 + (9.6 x weight in kg) + (1.85 x height in cm) - (4.7 x age in years) Merz REE = 66 + (13.7 x weight in kg) + (5.0 x height in cm) - (6.8 x age in years) The significant reduction in calorie intake, as suggested above, has occurred for a number of reasons. One being the recent realization.that critically ill individuals during hypermetabolic stress are unable to utiIize excess caIories and that despite delivery of adequate nutrients, endogeneous glucose production is not reversed and in fact continues. Thus, the excess calorie delivery, in fact, has been shown to result in  numerous metabolic compl~cationssuch a s hyperglycernia (presence of high Mcdicnl Nutrition Tllcrnpy in Criticnl Care concentration of glucose in blood), hyperinsulinemia (excessive level of insulin in blood) and hepatic steatosis (accumulation of fat in the liver) as indicated in Figure 4.1. Severe hyperglycemia is associated with glycosurea (excess glucose in urine) and hyperosmolar dehydration leading to grave disturbances of fluid and electrolyte homeostasis in the critically ill. In addition hyperglycernia has also been shown to result in significant reduction in neutrophil cell function. Hyperinsulinemia, on the otl~er hand, leads to increased sodium and water retention with resultant greatly increased ventilatory requirements due to impaired lung compliance as a result of increased lung and body water. Hyperinsulinemia also leads to inhibition of endogeneous lipolysis (hydrolysis of lipids) leading to greater carbohydrate utilization, increased carbon dioxide (CO,) production and impairment of respiratory function leading to increased morbidity. 1 EXCESS CALORIE DELIVERY r'-l Hyperglycelnia Osmotic Neutrophil dehydration 1function \ , /LIzk, Hepatic steatosis -1 1'1' Morbidity Figure 4.1: Effect of excess calorie delivory ia the critically ill The proportion of nutrients delivered to critically ill children has also undergone considerable change over the last decade or so. As a broad outline, calorie delivery amounts to 20-30 calories / k g / day during the unstable Ebb phase followed by 50-3.00 calories / kg / day during the recovery phase (depending on individual tolerance). What do we mean by the Ebb and the recovery phase? You will soon find out in the next unit. Protein intake of 1.5-3.0 &kg per day depending on renal and hepatic functional status is optimal has been recommended that carbohydrate in the form of glucose should not exceed from 4-6 mgPlcglminute. Hyperglycemia is often encountered in the sick stressed infant and older child. Blood sugars therefore should be retained ideally below 200 mg/dLin the criticaly ill stressed children. Regarding, lipid delivery, it is being recognized that long chain fatty acids (LCT) are potentially immunosuppressive when either administered rapidly or in large quantities, hence increased utilization of alternate lipid sources is becoming popular. Lipid emulsions which include medium chain triglycerides (MCT) and o-3-fatty acids are being increasingly used. The amount of lipid administered in the critically ill child has been reduced to 15-20% of total caloric intake, Besides the nutrients discussed above, several other specific nutrients have been reported to improve some body functions or even outcomes of hospitalized patients. The nutrients and drugs that have been reported to have beneficial nutritional effects on specific body functions and/or clinical outcomes are listed in Table 4 , l Clinical Therapeutic Table 4.1: Nutrients and drugs that have been reported to have beneficial Nutrition nutritional effects on specific body functions and/or clinical outcomes Branched Chain Amino Acids Alpha-ketogluterate (isoleucine, leucine and valine) Arginine Medium chain triglycerides Glutarnine Structured lipids Nucleotides o-3-fatty acids Growth hormones The question that we need to address ncxt, is how to administer the nutritional support to the critically ill or in other words what should be the optimal route of nutritional delivery. The next section focuses on this aspect. FEEDING METHODS IN ONAL SUPPORT From our discussion above, it is clear that an appropriate goal oriented nutritional support is of paramount importance in both decreasing morbidity, as well as, mortality in the hypermetabolic and stressed critically ill patient. Initial attempts to achieve nutritional goals in critically ill patients should be via oral route as highlighted in Figure 4.2. However, this may not be possible always. Sometimes a person cannot eat any or enough food because of an illness. The stomach or bowel may not be working quite right, or a person may have had surgery to remove part or all of these organs. Under those conditions, nutrition must be supplied in a different way. PEN is one such way. What does PEN stands for? PEN stands for parentral and ertteral nutrition. Oral Nutrition Possible L. Yes q No \1 Enteml Nonnalfood Norniai food Parenteral adequate inadequate Yes I ? Yes No adaptatiod V intervention Sip feeding (Oral Nut itional Supple~nents) Deficiency of energy V Drinks/Formulas n nutritionally complete providing proteins,cnrbohydrates Nitrogen enriched Energy enriched fat, vitaminand supplements, protein silpplements minerals - glucose polymers powder - - fat elnulsions Figure 4.2: Oral feeding option Both parenteral (pa-REN-te-rul) and enteral (EN-ta-rul) nutrition are in the form of a Medical Nutrition Therapy in Critical Care liquid. Enteral, is used when the gut is still partially working, but the patient callnot eat or absorb enough nutrients to stay healthy. Enteral is delivered directly into thc stomach or intestine through a feeding tube. Inparentera!, nutrients are delivered intravenously and the GI tract is bypassed entirely. Parenteral is given through a catheter, which carries the liquid directly into the bloodstream, where the body absorbs it. Figure 4.3 illustrates the two nutritional support methods. Figure 4.3: Enteral and parenteral n~ttritionsupport The goal of nutrition iiltervention is to supply adequate nutrients to inect the patient's nutrient requirement by the most physiologic, safety and cost effective route. Let u s get to know these two means of nutritional support better. 4.3.1 Enteral Nutrition (EN) By definition, the tern1 enteral tneans "within or by the way of the gastrointestinal (GI) tract." As described above, enteral is defined as provision of nutrition support through the gastro-intestinal (GI) tract or by accessing the gut. It also refers to feeding into the GI tract through a feeding tube. Enteral nutrition (EN) call be administcred via transoral (oral ingestion of food), transnasal (administration of liquid feeds through feeding tube through the nose), or percutaneous transgastric routes (through stomach), or by a tube into the small intestine called a jejunostomy or percutaileous endoscopic jcjunostoniy (PEJ). Hence, e~zteralrzutrition is often called tube feeding, EN is a method of providing adequate nutritiol~that is expected to prevent, improve, or reverse malnutrition in patients who are not receiving adequate nutrition orally. Enteral, is used when the gut is still partially working, but the patient cannot eat or absorb enough nutrients to stay healthy. Some of the benefitsladvantages of EN include: * it provides nutrition when oral intake is not possible or adequate, o it is easier to administer, present fewer metabolic and infectious complications (as compared to parenteral route), e the intake is easilylaccurately tnonitored, 9 enteral access is easy, gut integrity and motility are preserved and the stress response is attenuated, 83 Clinical Therapeutic e it reduces the incidence of pathogen entry or bacterial translocatio~~ into the Nutrition stonlnch cavity or circulation, e it provides Inore complete nutrients, trace elements and short chain fatty acids, a s well as, fibre. 0 it provides atrophic effect on thegut by promoting pancreatic and biliary secretion, as well as, endocrine, pancrine and neural factors that help promote the physiological and immunologic integrity of the GI tract. e the supplies are readily available, and e it is cost effective as compared to parenteral nutrition. In animal shdies, EN has shown to promote gut motility, it reduces bacterial translocation, prevents mucosal atrophy and stimulates the secretion of IgA that helps to reduce infectious complications. There is also evidence that EN improves nutritional- outcomes and results in greater wound Ilealing. 7 Clinically, EN shouldnot be considered an 'all or none therapy. For patients unable to take adequate nutrition by mouth despite an appropriate modified oral diet, EN can provide the remaining calories and proteins to meet estimated requirements. The indication for enteral feeding is therefore summarized in Figure 4.4 I EnteralFeed Indicated I Is patient eating solid food.t I Yes I Try oral nutrition options as given in Figure 4.2 e Is p;~ticn!i l i inking? i Drink feeds , Initiate enteral feeding1 tube feeding I (gastricmobility dissorder) I i Nasogastric tube through the nose into the stomach postpyrlorically (into the small bowel) Figure 4.4: Indication for eateral feed Jejunostomy What are the conditions when enteral feeding is indicated? Table 4.2 summarizes Medical Nutrition Therapy in Critical Core some important conditions. TaMe 4.2: Indications for enteric tube feeding for adults and children Indications Conditions For Adults Neurological indications Severe head injuries Cerebrovascular accidents &ma Neoplasms: advanced primary and secondary intracranial tumors Dysphagia associated with neurological disorders - Hypermetabolism Postoperative major surgery Sepsis Trauma, bums, organ transplant, acquired immune deficiency syndrome Surgical indications Facial and jaw surgeries Head and neck surgeries Oropharyngeal surgeries Pharyngoesophageal surgeries Polytrauma associated with extensive abdominal surgeries Patients with bums for surgeries unable to take oral nutrition Surgery conlplicated with sepsis Gastrointestinal (GI) Short-bowel syndrome (if absorplive capacity of disease remaining bowel is sufficient e.g.approximately a minimum of 100 cm jejunal and 150 cm of ileal length of functioning small bowel with ileocecal value intact) Inflammatory bowel disease Minimal GI tract fistula output ( less than 500 ml/d) Pancreatitis Oesophageal obstruction Malabsorption Fistulas Cancer Oral malignancies Oropharyngeal malignancies Nasopharyngeal malignancies Head and neck malignancies Oesophageal malignancies Gastric malignancies Chemotherapy Radiotherapy Resistance to oral Anorexia illtake Dysphagia Severe depression Malnutrition Protein energy malnutrition with inadequate oral intake for at least 5 days Malnutrition preoperatively and postoperatively Malnutrition in cancer patients Malnutrition in patients with Acquired Immune Deficiency Syndrome (AIDS), who are unable to take oral nutrition Malnutrition in debilitated aged patients Organ system failure Respiratory failure Renal failure Cardiacfailure Central nervous system failure Hepatic failure Multiple organ system failure For C h i n Malnutrition, malabsorption, hypermetabolism, failure to thrive, prematurity , disorders of absorption, digestion, excretion, utilization, or storage of nutrients ,  Clinical Tlicrnpeutic Once the indication for enteral nutritioil is established, the next issue that confroilts us Nutrition is what are the types of entcral i'eeds/fc~rmulasthat are available and c a n be delivered? The Drug and Food Administration (FDA), USA recognizes entel.al jbrrn~ilasas a category of product indepeizdent from regular foods, dietary supplements or drugs. Multitudes of enteral formulas are available for infusion. T h e formulas have been traditio~lallydivided into yoly~neric,oligomeric and modular. However, there are feeds, which can be home made or prepared with natural food items, or feeds, w h i c h are based on polymeric enteric diets such as disease specific feeds or opportunistic feeds. These different types of enteral feeds with their salient features are reviewed in Table 4.3. Table 4.3: Enteral feeds and their specific characteristics - Enteral Feeds/Formula Specific Characteristics Polymeric formulas - Provide nitrogen as whole protein, oflen casein, egg white solids or soy protein. (also called defined formula diets) - Carbohydrate is provided as corn syrup, maltodextrins or This is the general purpose, most widely prescribed feed. glucose oligosaccharides, with sucrose added for sweetness in It is the sole source of nutrition intake for critically ill oral formulas. individuals with or near normal GI function. - Fat is usually provided as soy oil, although corn oil and safflower oil may be used. Medium-chain triglyccrides (MCToil) are rarely 1 used. Oligomeric formulas (also called elemental or semi-elemental diets) Oligomeric diets are predigested and formu1;ited to 1 ' I - Most of tliese formulas provide enoug11protein, calories, water: electrolytes, minerals, vitamins and trace elements in 2 Uday for most "nonstressed" patients require minimal digestion by the gastrointestinal tract. I - Provide nitrogen as oligopeptides from partially hydrolyzed In other words, these diets are "complete." whole protein or as crystalline amino acids. - Carbohydrate tends to be provided as glucose oligosaccharidcs or glucose. - Fat is usually present in sr~iallquantities, enough to meet the requirement for linoleic acid (an essential fatty acid), which is about 2-4%of total calories. MCToil is added to some formulas. - Oligo~nericdiets have been coriTmercially promoled as ideal for patients with decreased bile output (cholcslasis), pailcreatic il~sufficiencvand short bowel. Modular formulaslfeeds - Modular formulas are those chat contain or predominantly (used when a particular component of the diet requires contain one kind of nutrient. an increased intake or if a patient requires a special blend - There are commercially available modules for protein, fat, of diets) carbohydrates, vitamins, electrolytes and trace elements. These modules are not required for the majority of Exainples of this might include burns or protein-losing patients, and are rarely used enteropathy, if more protein is to be given; or liver disease, if less protein is to be given. - - Prepared by mixing the ingredients and delivered in an, easily digestible form. - Provide carbohydrates, proteins and fat in the amount as in the I (For chronically ill patients with norinal GI functions) Disease specific feeds balanced diet. - For long-term nutritional management. - Natural food items are used to preparing thc feed. - For renal patients (these are specially formulated polymeric enteral feeds) - ' For liver disease patients (specialized amino acid solutions have been madc for use in special circumstances. For example, liver disease, renal disease and "stress," such as trauma and sepsis. For liver disease, these solutions are composed mostly or exclusively of brancl~ed-chain amino acids, whereas for renal disease the solutions are predominantly essential amino acids, Opportunistic feeds Addition and substitution include: (with nutritional addition and substitution which are -- moremiddle chain triglycerides(MST) suggested to improve various aspects of organ function) increased level of n-3 fatty acids, carnitine, beta carotene, RNA, arginine, glutamine etc, Drink feeds (for those who cannot eat solid foods but can ingest Nutritionally complete enteral feeds based on polymeric enteral diets liquid diets) Palat8ble 86 Therefore, it is evident that various enteral formulas are available for infusion. So, Medical Nutrition Therapy in Critical Care which one to select? Well, the factors to consider when choosing an enteral formula include: gastrointestinal function, e the type of protein, fat, carbohydrate and fibre in the formula as related to the patients digestive and absorptive capacity, e calorie and protein density of the formula (i.e. Kcallml, g proteinlml and Kcal: nitrogen ratio), e sodium, potassium, magnesium and phosphorous coiltent of the formula, especially for patients with cardiopulmonary, renal or hepatic failure, and e viscosity of the formula related to tube size and method of feeding. The nutrition composition of enteral forinulas given in Box 1. Box 1 Enteral Forrnl~laComposition - Most of the formula provide 1.0-1.2 Kcallml. In high concentrations, they 1 may provide 1.5-2.0 Kcallml. - Proteins in enteral formulas provide 4% to 32% of total calories. Those formulas providing 18 to 32% of calories are considered high-protein solutions. - Carbohydrates contribute 40% to 90% of total calories in enteral formulas. Carbohydrate sources used in formulas Bre pureed fruits and vegetables, corn syrup solids, corn and tapioca starch liydrolysates, maltodextrins, sucrose, fructose and glucose. - Lipid provides 1.5% to 55% of the total calories of enteral formulas. - Water recommended. 6 Healthy adult : 1 rnl/Kcal or 35 mlkg. o kealthy infant: 1.5 ml/Kcal or 150 ml/kg. e Elderly: consider 25 mllkg with renal, liver, or cardiac failure; or consider 35 ml/kg if history of dehydration e Normal tube feeding: 1 Kcallml; 80% to 85% water Some of the commercially available, ready to use enteral formulasJdietsfor paediatric patients are given in Table 4.4. This information, we hope will be of use, during your dietetic practice. So read this information carefully. Do add on to this list the other enteral feeds/formulas that you might come across during your study or practice. Table 4.4 : Enteral nutrition commercial formulas for paediatric use - Product Company Calories/100 g NOURISH Claris 518 SIMYL MCT FDC 460 PEDIA SURE (powder, reconstitute with water, ideal for both oral and tube feeding) Abbott 496 - PROSOYAL FDC 506 IMPACT (IB) Novartis 484 NOVASURE Novartis 400 CIinicnl Therapeutic - Nutrition RESOURCE JUNIOR (contain lactose, Novartis 200 (per sachet of fibre and gluten free) 42 g) - LACTODEX (complete low lactose, low Raptakos 55 (each 100 ml of fat nutrition during diarrhoea) reconstitution) LACTODEX-LBW(feeding of preterml Raptakos 80.3 (each 100 ml LBW infants until sufficient mother's milk of reconstitution) is available) MILK CARE LBW (life saving formula Dalmia 501 for premature/LBW infants) ZEROLAC (for lactose intolerance, acute Raptakos 64 (each 100 ml of chronic diarrhoea) reconstitution) ENERGEX (lactose intolerance to hdon 506 cow's milk) Rapatakos TROPHOX (protein supplement) Nutrition in Diseases Management. Update Series 1: Pediatric and Enteral Nutrition in the - Source: Indian Context. Centre for Research on Nutrition Supporl System. Besides the formulas listed above few enteral formulas for older children (over 4 years of age) are also included in Table d5. Table 4.5: Enteral formulas for children over 4 years of age Complete Balanced Semi- Disease Specific Balanced Formula with elemental, Nutrition Additives Partially Formula Hydrolyzed FE~IASURE Fresubjn PERATIVE- DIABETIC (Powder) Isofibre partially Glucerna hydrolyzed Fresubin Diabetic RES SUB IN- Nutren fibre protein Resource Diabetic liquid:lactose, Nutrocal DM cholestrol and SURVIMED HEPATIC gluten free OPD - Fresubin Hepa oligopeptide Resource Hepa NUTREN 1.0- powder PEPTAMEN RENAL - exceptional Nephro - post RESOURCE - peptide dialysis, 475 Kcal, powder: lactose formula can be given orally free Suylena- pre dialysis. 475 Kcal, can be HORLICKS given orally PLUS: Powder Nutrenal CRF - pre dialysis, 518 Kcal, can be given orally Nutrenal TM - post dialysis, 518 Kcal, can be give11 orally r I Source: Nutrition in Diseases Management. Update Series 1: Pediatric and Enteral Nutrition in the Indian Context. Centre for Research on Nutrition Support System. \ I In the formulas listed above, you would have noticed the calorie content given for each formula. How is the energy and protein content of the formula deternlined? The formula used includes: - Kcallml x ml given = Kcal - % protein x Kcal = Kcal as protein - Kcal as protein x 1 g/4Kcal = g protein i' Let us try to understand this equation with the help of an example. Medical Nutrition Therapy in Critical Care Example: Patient drinks 100 ml of a 18.2% protein product that has 1 Kcal/ml. ' Therefore the calorie, protein content would be: - 1 Kcallml x 100 ml = 100 Kcal ' - 0.182 % protein x 100 Kcal = 18.2 Iccal - 18.2 Kcal x lg protein14 Kcal = 4.55 g protein The common methods of administering the enteral formulas include: e Continuous method = slow rate of 50 to 150 nlllhr for 12 to 24 hours, e~ Intermittent method = 250 to 400 ml of feeding given in 5 to 8 feedings per 24 hours, and e Bolus method = may give 300 to 400 ml several times a day. With a detail review of the nutrient composition and method of administering the enteral formulas, we shall end our study on enteral nutrition by reviewing the disadvantages and complications, if any linked with enteral feeding. Disadvantages and Conzplicatiorts of Enteral Feeding There are a few comnlon complications linked with the use of enteral feeding. These complications include: cs Access problems (tube obstruction) @ Administration problems (aspiration, tube migration) e Gastrointestinal complications (diarrhoea) e Metaboliccomplications (overhydration) Besides the complications mentioned above, use of cnteral feeding is associated with increased risk of bacterial contamination especially in case of home made blendcrized foimula. Further, they may be labour intensive and may require site care and monitoring. Thky are 'less palatabley and do cost inore than oral diets. Next, let us get to know about the parenteral nutrition. Before we begin our study, however let us review what we have learnt so far by answering the check your progress exercise 1 given next. Check Your Progress Exercise 1 I 1. Enumerate the nutrient requirements of the critically ill adult. 2. What are the types of nutrition support we can provide to a critically ill individual? Elaborate.................................................................................................................................................................................................................................................................................................................",.....,..,.,...#...~....,.,.........,...................................................................................................................................... Clinical Therapeutic 1 Nutrition 3. When is enteral nutrition indicated? List atleast disease conditions.................................................................................................................................................................................................................................................................................................................................................................................................................................................... 4. List the dserent types of enteral fonnulas/feedswhich can be made available for the critically ill patient.................................................................................................................................................................................................*.................*...................................................................................................................................................................................................................................................................... Now that we are clear on enteral nutrition let us get to know about parenteral nutrition. 4.3.2 Parenteral Nutrition Enteral nutrition, we learnt, above means within or by the way of gastrointestinal tract. Parenteral nutrition, on the other hand, refers to nutrients delivered to the patient in a manner other than through the gastrointestinal (GI) tract - usually delivered intravenously (bypassing the digestive tract) as you may have noticed in Figure 4.3. Parenteral nutrition is one of the ways people receive food when they cannot eat and there is a dysfunctioning of the digestive tract. It is a special liquid food mixture administered into the blood through a vein. The mixture contains all the protein, sugars, fat, vitamins, minerals, and other nutrients needed. It is sometimes called "total parenteral nutrition," "TPN," or "hyperalimentation." Parenteral nutrition, in fact, can be of two types - total parenteral nutrition (TPN) and partial parenteral nutrition (PPN). TPN supplies all of the patient's daily nutritional requirements. Partial parenteral nutrition, on the other hand, supplies only part of the patient's daily nutritional requirements, supplementing oral intake. Many hospitalized patients receive dextrose or amino acid solutions by this method as part of their routine care. When is the use of parenteral nutrition indicated? Parenteral nutrition support is indicated in the presence of compromised nutritional status when adequate nutrients (protein and calories) cannot be provided by oral or enteral route or when oral or enteral feeding is insufficient (as in burns or polytrauma), undesireable (as in the case of fistulas), ineffective (short bowel syndrome, severe malabsorption) or impossible (intestinal obstruction or pseudo obstruction). In other words, parenteral nutrition is generally used when the enteral route is either inaccessible or its use is contraindicated. It is also used as a supplement to enteral feeding if adequate nutrition is not possible via the enteral route alone. This type of nutrition is used in the most critical patients, which may have one or more of the following symptoms: o Intestinal obstruction or ileus, e Inadequate digestive or absorptive capacity, 1 7 a Uncontrollable vomiting (this is particularly life threatening to a diabetic patient), Inability to tolerate food for any reason (e.g. head trauma, burns to mouth/face/ I oesophagus), I ' e High risk of aspiration because patient is unconscious or has a neurologic problem, and I i e Need for complete GI tract rest due to digestive disease, healing time needed for GI tract lesions or surgical repairs, acute pancreatitis or hepatitis. In infants and children parenteral nutrition is indicated during intestinal failure (short IMsdieoD NuCriLioit Therapy in Critical Care gut, protacted diarrhoea, post-operative abdominal or cardio-thoracic surgery, radiation etc.), organ failure (acute renal or liver failure), and hyper-catabolism (as in extensive burns, severe trauma etc.). The advantages of using parenteral nutrition is that it: e provides nutrients when less than 2 to 3 feet of small intestine remains, when surgical procedures are carried out and e allows nutrition support when GI intolerance prevents oral or enteral support Parenteral support is generally given for a short period (two weeks or so), at which point the patient has hopefully begun to recover from the symptoins that caused the need for this type of support in the first place. PN may include a combination of sugar and carbohydrates (for encrgy), proteins (for muscle strength), lipids (fat), vitamins, electrolytes, and trace elements. Electrolytes include sodium, potassium, chloride, phosphate, calcium, and magnesium. Trace elements i~icludezinc, copper, manganese, and chromium. Vitamills includc, vitamins - A, C, D, l3,I