DefinitionsDefinitionsFoodFood: - 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

nutrientsnutrients. 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 mostnutrients and is needed for all cellular activities.

Why human beings need Why human beings need food?food?

Human beings need food to provide energy for the essentialphysiological functions like:-.. Respiration.. Circulation.. Digestion.. Metabolism.. Maintaining body temperature... Growth and repair body Tissues

CarbohydratesCarbohydrates

• 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.

Fats 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

Fats continued…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.

Proteins 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.

Water and Water and electrolyteselectrolytes

• 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.

Intravenous Vitamins: RDI 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

Mineral requirementsMineral requirementsMineral Recommended

Daily Intake: Enteral

Recommended Daily Intake: Parenteral

Sodium 90 – 150 mEq 90 -150 mEq

Potassium 60 – 90 mEq 60 -90 mEq

Magnesium 350mg 10 -30 mEq

Calcium 1000mg 10 – 20 mEq

Phosphorus 1000mg 10 – 35 mmol

The energy requirementsThe energy requirementsThe 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 lessenergy.

♦ Climate: Both very cold and very hot climate restrict outdooractivities.

In general feeding is dependent on the controlling centres, appetiteand satiety in the brain. There are a variety of stimuli, nervous,

chemical and thermal, which may affect the centres and so alterfeeding behaviour.

Calculation of daily Calculation of daily requirementrequirement

• 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)

Convert requirements Convert requirements into prescriptioninto prescription

• Determine volume of lipid emulsion: 10% lipid emulsionFluid 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 % solutionVolume of amino acids = 60/10 X 100 = 600 ml

• 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 emulsion600ml of 10% amino acid and1000 ml of 20% dextrose

StarvationStarvation• Adult volunteers

o Fasted for 30-40 days: 25% weight loss

o More prolonged fasting: 50% weight loss

• Weakness

• Apathy

• Reduced work capacity; cardiorespiratory failure

• Total starvation is fatal in 8 to 12 weeks

Assessing Nutritional StatusAssessing 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

Assessing Nutritional Status:Assessing Nutritional Status:SGA – Subjective Global SGA – Subjective Global

AssessmentAssessmentA. 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

Nutritional assessment….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.

• S. Transferrin, TBPA, RBP and Fibronectin Transferrin- Half life 8 days TBPA Half life 2 days RBP Half life 12 hrs Fibronectin 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.

Timing of nutritional supportTiming 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.

Routes of feedingRoutes of feeding

Enteral nutritionEnteral 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.

Indications of Enteral Indications of Enteral nutritionnutrition

• 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.

Indications continued… 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).

Contraindications of Contraindications of Enteral nutritionEnteral 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.

Routes of enteral Routes of enteral nutritionnutrition

Jejunal feeding is likely to be the best

Starting tube feedsStarting tube feeds

Gastric feedingGastric feedingAdvantages:

•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

Monitoring of gastric residual volume

every 2-4 hrs:

mandatory

Complications of Complications of enteral feedingenteral feeding

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

Complications of Complications of enteral feedingenteral feeding

Metabolic/bio-chemical•Electrolyte disorder•Vitamin, minirals, trace elements deficiencies•Drug interactionsInfetive•Exogenous (handling contamination)•Endogenous (patient)

Parenteral nutritionParenteral 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.

Indications of parenteral Indications of parenteral nutritionnutrition

• General indicationso 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

enterallyo Pre existing severe malnutrition with inadequate oral or

enteral nutrition.• Anticipated or actual inadequate oral or enteral intakeo Conditions that impair absorption of nutrients: Enterocutaneous fistula

Common Indications for Common Indications for PNPN

• Inability to absorb adequate nutrients via the GI tract :o Massive small-bowel resection / short bowel syndromeo Severe, untreatable steatorrhea / diarrhoea / malabsorptiono Complete bowel obstruction, or intestinal pseudo-obstructiono 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

Short bowel syndrome Small bowel obstruction Effects of radiation or chemotherapyo Need for bowel rest: Severe pancreatitis Inflammatory bowel disease Ischemic bowel Peritonitis Pre and post op statuso Motility disorders: Prolonged ileus

o 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.

Parenteral Nutrition TeamParenteral Nutrition TeamPossible MembersPossible Members

• Nutritionist – expertise across PN, EN, short bowel• Pharmacist – with nutritional / PN expertise• Physician – with nutritional expertise• Specialist Nutrition Support Nurse• Support groups

o Vascular access team – PICC lineso Diagnostic imaging – Central lines / portso Infectious diseaseso Enterostomal therapyo Surgery

St. Bartholomew’s Hospital/Science Photo Library

Delivering parenteral Delivering parenteral nutritionnutrition

Peripheral IV: short-linePeripheral IV: short-linePROS• Least expensive• Easily placed and

removed• Lowest risk for CRI• Beneficial for short-term

support (< 1 week)

CONS• Need to change often

o Every 48-72h

• Phlebitis and vein injury• Only one lumen• Limits energy delivery

o Volumeo Osmolality (600-900 mOsm/l) o pH restriction (pH 5-9)

Central parenteral Central parenteral nutritionnutrition

• Most efficient way to deliver all the nutrients by central venous catheter inserted in SVC or IVC.

• Composition: varied compositionConc. 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)

Peripherally Inserted Central Peripherally Inserted Central Catheter (P.I.C.C.) LineCatheter (P.I.C.C.) Line

Tip in SVC

O

• More expensive than peripheral lines

• More difficult to place

• Last up to 6 - 12 months

• Restrict arm movement

• Allow higher osmolarity “Central” TPN solutions

Systems for delivering Systems for delivering PNPN

Multiple bottle systemMultiple 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.

Multiple bottle systemMultiple 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 system3 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.

3 in1 system3 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.

• 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

Clinical data monitored Clinical data monitored dailydaily

• 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.

Laboratory dataLaboratory dataFingerstick glucose test 3 times daily until pt. stable

Blood glucose, Na, K, Cl, HCO₃, BUN

Daily until glucose infusion load and pt. stable, then twice

weekly

LFT, S.Creatinine, albumin, PO₄, Ca, Mg, Hb/Hct, WBC

Baseline, then twice weekly

Clotting, INR Baseline, then weekly

Micronutrient test As indicated

Monitoring response to nutritional therapy:Improvement in clinical status, Protein concentrations

(Albumin, prealbumin, transferrin)

Complications of parenteral Complications of parenteral nutritionnutrition

Mechanical Metabolic/ GI Infectious

First 48 hrs.

Malposition, Haemothorax,

Pneumothorax, Air embolism, Blood loss,

Puncture of Subclavian/ Carotid

Art.

Fluid overload, Hypoglycemia,

Hypophosphatemia, Hypokalemia,

Hypomagnesemia, Refeeding syndrome

_ _

First 2 weeks

Catheter displacement, Thrombosis,

occlusion, Air embolism

Hypoglycemic coma, Acid base and

Electrolyte imbalance

Catheter induced sepsis, Exit site

infection

3 months onwards

Tear of catheter, catheter thrombosis, Air embolism, blood

loss

Ess. FA def., Vitamins or trace

element def, Metabolic bone ds.,

Liver ds.

Tunnel infection, Catheter induced sepsis, Exit site

infection

Metabolic Complications of Metabolic Complications of

Parenteral Nutrition – 1Parenteral Nutrition – 1

• Electrolyte imbalanceoNa, K, Mg, PO4, Ca

• Hyperglycemia / hypoglycemia

• Dehydration

• Fluid Overload

• Metabolic Acidosis

Metabolic Complications of Metabolic Complications of

Parenteral Nutrition - 2Parenteral Nutrition - 2

• Hyperlipidemia

• Hypercapnea

• Vitamin/trace element deficiencies

• Essential fatty acid deficiency

• Liver dysfunction

Hepatic DiseaseHepatic Disease• Cholestasis (incl “sludge) + Hepatocellular disease

• Impaired hepatic transulfurationo 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

Metabolic Bone DiseaseMetabolic 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

Possible ComplicationsPossible Complications

Associated with Long-Term TPNAssociated with Long-Term TPN

• Gastrointestinal dysfunction

• Trace element deficiencies

• Hepatic steatosis/cholestasis

• Metabolic bone disease

• Psychosocial difficulties

• Financial difficulties