Definitions

1. Definitions Food: - is defined as any solid or liquid which when ingested will enable the body to carry out any of its life function. Most foods are made up of several simple substances, which we call nutrients. There are six nutrients each of which has specific function in the body. Those that supply energy are the carbohydrates and fats. Those responsible for growth and repair of tissues cells are proteins. Those, which regulate chemical process in the body, are the vitamins and minerals. Water is present in most foods and is an indispensable component of our bodies. It is the means of transportation for most nutrients and is needed for all cellular activities.

2. Why human beings need food? Human beings need food to provide energy for the essential physiological functions like:- .. Respiration .. Circulation .. Digestion .. Metabolism .. Maintaining body temperature. .. Growth and repair body Tissues

3. Carbohydrates • Ready fuel for energy, less expensive and Nitrogen sparing effect. • RBCs, WBCs and renal medulla require glucose and brain prefers glucose as fuel. • Disadvantages: excess carbohydrates inc. , Glucagon secretion and Insulin resistance • Severe hyperglycemia in sepsis (impaired utilization). • Excessive glucose -› fat -› Hepatic Steatosis • Excess glucose inc. CO₂ production -› pulmonary work load.

4. Fats • Provide energy • Regulation of Cardiovascular tone ( PGs) • Components of cell membranes ( Phospholipids) • Cellular messengers (Phosphoinositides) • Immune function • Linoleic acid: essential fatty acid should provide 4% of total calorie intake

5. Fats continued… • Diets high in linoleic acid - immunosuppressive Low intake – improves immune function • Deficiency of linoleic acid: eczema like rash, neutropenia and thrombocytopenia. • ω-6 and ω-3 PUFA are essential fatty acids. • ω-6 PUFA – ω-3 PUFA ratio should be 1:1.

6. Proteins • Minimum intake: 0.5g/kg/day • Intact digestion : intact protein diet • Impaired digestion: peptides (< 10 amino acids) based diet advantageous (dec. diarrhoea, improved wound healing and inc. protein synthesis). • Restrict proteins if BUN > 100mg/dl and rising or elevated NH₃ assoc. with encephalopathy.

7. Water and electrolytes • 25ml/kg dry body weight of fluids to avoid dehydration. • Adults : 1ml/kcal consumed; Infants: 1.5ml/kcal consumed • K, Mg, PO₄ and Zn in amounts to maintain normal serum levels. • RDA for all vitamins and minerals usually provided in 1000 – 1500 ml of most enteral formulas.

8. Intravenous Vitamins: RDI Vitamin • Thiamine (B1) 6 mg • Riboflavin (B2) 3.6 mg • Pyridoxine (B6) 6 mg • Cyanocobalamin (B12) 5 mcg • Niacin 40 mg • Folic acid 600 mcg • Pantothenic acid 15 mg • Biotin 60 mcg • Ascorbic acid (C) 200 mg • Vitamin A 3300 IU • Vitamin D 5 mg • Vitamin E 10 IU • Vitamin K 150 mcg

9. Mineral requirements

10. The energy requirements The energy requirements of individuals depend on ♦ Physical activities ♦ Body size and composition ♦ Age may affect requirements in two main ways – During childhood, the infant needs more energy because it is growing – During old age, the energy need is less because aged people are engaged with activities that requires less energy. ♦ Climate: Both very cold and very hot climate restrict outdoor activities. In general feeding is dependent on the controlling centres, appetite and satiety in the brain. There are a variety of stimuli, nervous, chemical and thermal, which may affect the centres and so alter feeding behaviour.

11. Calculation of daily requirement • Sample calculation for 60 kg, stable, euvolemic pt. with good urine output and moderate stress • Fluid requirement: 35ml/kg = 2100 ml/day • Calories: 25kcal/kg = 1500 kcal/day • Proteins: 1g/kg = 60 g/day = 240 kcal/day (4kcal/g) • Fats: 30% of total calories = 450 kcal/day = 50g fat(9kcal/g) • Carbohydrates: 1500 – (240+450) = 810kcal = 202.5g of dextrose (4kcal/g)

12. Convert requirements into prescription • Determine volume of lipid emulsion: 10% lipid emulsion Fluid volume reqd. = Amt. of substance(gm) X 100 Conc. Of substance(%) Volume of lipid emulsion= 50/10 x 100 = 500 ml • Determine volume of amino acid infusion: 10 % solution Volume of amino acids = 60/10 X 100 = 600 ml

13. Selection of dextrose infusion: in remaining 1000 ml volume, 202.5g dextrose needs to be infused. 1000 = 202.5 X 100 Conc. of subst. • Concentration of substance = 202.5/1000 X 100 = 20.25% = 20% approx. • Prescription: Pt. needs 500ml of 10% lipid emulsion 600ml of 10% amino acid and 1000 ml of 20% dextrose

14. Starvation • Adult volunteers • Fasted for 30-40 days: 25% weight loss • More prolonged fasting: 50% weight loss • Weakness • Apathy • Reduced work capacity; cardiorespiratory failure • Total starvation is fatal in 8 to 12 weeks

15. Assessing Nutritional Status • Focused nutrition history • Assess current weight and weight-loss history • Physical examination • Assess malabsorption • Fecal fat test • Schilling test • Hydrogen breath test • D-xylose

16. Assessing Nutritional Status:SGA – Subjective Global Assessment A. History • Weight change <5% = “small”5–10% = “potentially significant” >10% = “definitely significant” • Change in dietary intake • Gastrointestinal symptoms(nausea, vomiting, diarrhea, anorexia) • Functional capacity • Disease and its relation to nutritional requirements B. Physical Anthropometric measurements • Loss of subcutaneous fat • Muscle wasting • Ankle edema • Sacral edema • Ascites C. SGA Rating • A = Well nourished • B = Moderately malnourished • C = Severely malnourished

17. Nutritional assessment…. • Body Mass Index: Height, Body weight etc. Unreliable • Biochemical Data: • S.Proteins and S. Albumin: index of visceral and somatic protein stores. Hypoalbuminemia: Overhydration, inc. catabolism Decreased synthesis ( liver ds.) Increased loss ( burns, large wounds, etc) • Note: S. Albumin level serve as a marker for initial nutritional state. It does not serve as marker for improved nutritional state following nutritional support.

18. S. Transferrin, TBPA, RBP and Fibronectin Transferrin- Half life 8 days TBPA Half life 2 days RBP Half life 12 hrsFibronectin Half life 12 hrs Can be used as markers of improved nutritional status. Limitation : Costly • S.Electrolytes, Renal and Hepatic function tests, Pulmonary function tests.

19. Timing of nutritional support • Nutritional support should be started before effects of starvation appear. • Note : In acute hypercatabolic critical illness, stabilization of hemodynamics and correction of fluid, electrolytes and acid base status takes precedence over nutrition.

20. Routes of feeding

21. Enteral nutrition • If the bowel works, use it. • More physiologic, safe and less expensive. • Preserves gut integrity, barrier and immune function. • Supplies gut preferred fuels (glutamine, glutamate and short chain fatty acids), unlike standard PN. • Prevents cholelithiasis by stimulating GB motility. • Recommendation :Initiation within 24-48 hrs of ICU admission in hemodynamically stable pts.

22. Indications of Enteral nutrition • Malnourished patients whose oral intake is poor for 3 – 5 days. • Well nourished patients with poor oral intake for 7 – 10 days. • Inability to eat adequately ( oropharyngeal lesions, oesophageal lesions etc.) • Following massive small bowel resection. • Enterocutaneous fistulae with output < 500ml/day.

23. Indications continued… • Severe full thickness burns (early enteral feeds limit sepsis and reduce protein loss from bowel) • Following major upper GI surgery ( Total gastrectomy, Total oesophagectomy, feeds through jejunostomy tubes). • Following surgery for necrotizing suppurative pancreatitis ( initial TPN is followed by jejunostomy or nasojejunal feeds following recovery of bowel function).

24. Contraindications of Enteral nutrition • GI causes: severe diarrhoea, paralytic ileus, intestinal obstruction, severe GI bleeding, acute pancreatitis and high output external fistula. • Cardiac causes: haemodynamic instability, low cardiac output, circulatory shock. Potential risk of GI ischemia. • Lack of access: unobtainable safe access to GIT. • Complications of enteral feeding: aspiration, severe diarrhoea and intestinal ischemia or infarct.

25. Routes of enteral nutrition

26. Jejunal feeding is likely to be the best

27. Starting tube feeds

28. Gastric feeding • Advantages: • Stomach initiates digestion • Gastric acid secretion sterilizes gastric contents ( risk of bacterial • contamination reduced) • Stomach protects gut from osmotic load (motility reduced in presence of hyperosmolar fluid and diluted till isoosmolar ) • Disadvantages: • Development of gastric atony • Risk of aspiration of gastric contents Monitoring of gastric residual volume every 2-4 hrs: mandatory

29. Complications of enteral feeding Tube Related Malposition Displacement Blockage Breakage/leakage Local complications (eg. Erosion of skin/mucose) Gastrointestinal Diarrhoea Bloating, nausea, vomiting Abdominal cramps Aspiration Constipation

30. Complications of enteral feeding Metabolic/bio-chemical Electrolyte disorder Vitamin, minirals, trace elements deficiencies Drug interactions Infetive Exogenous (handling contamination) Endogenous (patient)

31. Parenteral nutrition • Definition : Total parental nutrition (TPN) is defined as the provision of all nutritional requirement by means of the intravenous route and without the use of the gastrointestinal tract.

32. Indications of parenteral nutrition • General indications • Inadequate oral or enteral nutrition for atleast 7-10 days (ASPEN and CCPG). • ESPEN: initiate within 24-48 hrs of ICU pts who can’t be fed enterally • Pre existing severe malnutrition with inadequate oral or enteral nutrition. • Anticipated or actual inadequate oral or enteral intake • Conditions that impair absorption of nutrients: • Enterocutaneous fistula

33. Common Indications for PN • Inability to absorb adequate nutrients via the GI tract : • Massive small-bowel resection / short bowel syndrome • Severe, untreatable steatorrhea / diarrhoea / malabsorption • Complete bowel obstruction, or intestinal pseudo-obstruction • Prolonged acute abdomen or ileus • Severe catabolism & GI tract unusable within 5–7 days • Enteral access not feasible, not adequate or not tolerated • Pancreatitis with intolerance (eg pain) of jejunal nutrition • High output EC fistula (>500 mL) & no distal enteral access

34. Short bowel syndrome • Small bowel obstruction • Effects of radiation or chemotherapy • Need for bowel rest: • Severe pancreatitis • Inflammatory bowel disease • Ischemic bowel Peritonitis • Pre and post op status • Motility disorders: Prolonged ileus

35. Inability to achieve or maintain enteral access: • Haemodynamic instability • Massive GI bleeding • Unacceptable aspiration risk • Hyperemesis gravidarum, eating disorders • Significant multiorgan system disease • Significant renal, hepatic or pulmonary disease • Multiorgan failure, severe head injury, burns etc.

36. Parenteral Nutrition TeamPossible Members • Nutritionist – expertise across PN, EN, short bowel • Pharmacist – with nutritional / PN expertise • Physician – with nutritional expertise • Specialist Nutrition Support Nurse • Support groups • Vascular access team – PICC lines • Diagnostic imaging – Central lines / ports • Infectious diseases • Enterostomal therapy • Surgery

37. St. Bartholomew’s Hospital/Science Photo Library

38. Delivering parenteral nutrition

39. Peripheral IV: short-line CONS • Need to change often • Every 48-72h • Phlebitis and vein injury • Only one lumen • Limits energy delivery • Volume • Osmolality (600-900 mOsm/l) • pH restriction (pH 5-9) PROS • Least expensive • Easily placed and removed • Lowest risk for CRI • Beneficial for short-term support (< 1 week)

40. Central parenteral nutrition • Most efficient way to deliver all the nutrients by central venous catheter inserted in SVC or IVC. • Composition: varied composition Conc. forms of dextrose(50-70%) and amino acids (8.5-10%). Osmolarity 1000-1900 mosm/l • Selection of catheter for CPN: Polyurethane(for short term use) or silicon rubber(mths to yrs)

41. Peripherally Inserted Central Catheter (P.I.C.C.) Line O Tip in SVC • More expensive than peripheral lines • More difficult to place • Last up to 6 - 12 months • Restrict arm movement • Allow higher osmolarity “Central” TPN solutions

42. Systems for delivering PN • Multiple bottle system • Flexible and easy to adjust. • Needs proper monitoring to avoid Hyperglycemia and hypertriglyceridemia • Higher risk of incompatibility due to improper mixing of nutrients. • 3 in1 system • Most efficient method of PN • Convenient, cost effective • Less chances of infection • Less metabolic complications • Less flexibility in changing contents. • Lesser stability d/t lipids.

43. Continuous parenteral nutrition: • Recommended in acute, critical and hospitalized pts. • Advantages: slow continuous infusion avoids volume overload, hyperglycemia and hypertriglyceridemia. • Cyclic parenteral nutrition: • PN delivered over 8-12 hrs. • Effective for stable, chronically ill pts. needing nutrition support. Eg. Home PN. • Avoid in: Glucose intolerance and fluid overload

44. Clinical data monitored daily • History: fever, h/s/o fluid overload or glucose and electrolyte imbalance. • Vital signs: Temp., HR, BP, RR • Fluid balance: input/output chart, weight • Local care: inspection and dressing of site of vascular access. • Delivery system: inspection of solution for contamination and functioning of infusion pump.

45. Laboratory data Monitoring response to nutritional therapy: Improvement in clinical status, Protein concentrations (Albumin, prealbumin, transferrin)

46. Complications of parenteral nutrition

47. Metabolic Complications of Parenteral Nutrition – 1 • Electrolyte imbalance • Na, K, Mg, PO4, Ca • Hyperglycemia / hypoglycemia • Dehydration • Fluid Overload • Metabolic Acidosis

48. Metabolic Complications of Parenteral Nutrition - 2 • Hyperlipidemia • Hypercapnea • Vitamin/trace element deficiencies • Essential fatty acid deficiency • Liver dysfunction

49. Hepatic Disease • Cholestasis (incl “sludge) + Hepatocellular disease • Impaired hepatic transulfuration • Transulfuration products facilitate: • Fat mobilisation • Lipid membrane stability • Bile secretion • May progress to liver failure / transplantation • Treatment: - do not overfeed - ursodeoxycholic acid - enteral supplements - carnitine

50. Metabolic Bone Disease • Pre-existing disease & malabsorption • Aluminium contamination • Inadequate calcium provision • Excess Vitamin D in TPN - measure both 25-OH & 1,25 DHCC • Monitor DEXA, Ca++, Vit D, PTH, Albumin