Total parenteral nutrition

• DEFENITION : is defined as the provision of all nutritional requirements by means of intravenous route and without the use of GIT.

INDICATIONS: 1. PRIMARY THERAPY: • gastrointestinal cutaneous fistulas• Short bowel syndrome due to massive resection of

small intestine• Acute burns• Hepatic failure( acute decompensation

superimposed on cirrhosis)• Renal failure (acute tubular necrosis)

2. SUPPORTIVE THERAPY: • Prolonged ileus• Weight loss preliminary to major surgery• Acute radiation enteritis• Patient with cancer

Routes of access

PERIPHERAL • peripheral feeding is appropriate for short term feeding of up

to 2 weeks • 2 types1. PICC peripherally inserted central venous

catheter2. Conventional short cannula in wrist vein

PICC

ADVANTAGE Bed side technique Avoids complications

of central venous catheter

Avoid multiple venous cannulations

Hypertonic solutions can be given

DISADVANTAGE Trained personnel is

needed Line blockage Mal position Phlebitis Line sepsis thrombosis

• Short cannula in wrist vein AdvantagesInfusing on cyclical basis for 12hoursCannula is then removed and resited in to contralateral arm

Peripheral parenteral nutrition (PPN) The osmolarity of PPN solutions generally is

limited to 1,000 mOsm (approximately 12% dextrose solution) to avoid phlebitis.

Thus, large volumes (>2,500 mL) are needed.Temporary nutritional supplementation with PPN

may be useful Generally intended as supplement to oral feeding

and is not optimal for critically ill pts

CENTRAL

Preferred site for access site: subclavian > jugular> femoral veinHICKMAN lines are preferable for long term parenteral nutrition. • Post insertion chest x ray is required before feeding to

rule out pneumothoraxCatheter tip lies in distal superior venacava to minimise the risk of central venous or cardiac thrombosis

CENTRAL CATHETER

ADVANTAGE Central access needed Multiple lumen can be

used in acute emergency

Hypertonic solutions can be given

Can be placed for than 6 weeks

DISADVANTAGE Inserted in theatre Increase infection rate Multiple complications

Enteral v/s parenteral Enteral nutrition is associated with fewer

complications than parenteral nutrition and is less expensive to administer.

However, the use of enteral nutrition alone often does not achieve caloric targets.

In addition, underfeeding is associated with weakness, infection, increased duration of mechanical ventilation, increased duration of hospital stay and death.

Combining parenteral nutrition with enteral nutrition constitutes a strategy to prevent nutritional deficit but may risk overfeeding which has been associated with liver dysfunction, infection, and prolonged ventilatory support.

Types of TPN formulations TPN formulation without lipid (2-in-1

solution)Calories from amino acids- 20 to 25%Calories from dextrose- 75-80%

TPN formulation with lipid ( 3-in-1 solution) calories from amino acids- 20 to 25% calories from lipids- 20% calories from dextrose- 55 to 60 %

Medications:

Albumin, H2-receptor antagonists, heparin, iron, dextran, insulin can be administered in TPN solutions. However, not all medications are compatible with 3-in-1 admixtures.

Regular insulin should initially be administered subcutaneously according to a sliding scale, based on a determination of the blood glucose level. After a stable insulin requirement has been established, insulin can be administered in the TPN solution, generally at two thirds of the daily subcutaneous insulin dose.

Energy requirements

Basal energy requirement is the function of the individual's weight, age, gender, activity level and the disease process

The major components of energy output are resting energy expenditure and physical activity; minor sources include the energy cost of metabolizing food and shivering thermogenesis.

Total energy expenditure= resting energy expenditure (70% of TEE) +thermic effect of food (10% of TEE) + energy expenditure of physical activity (20% of TEE)

Average energy intake is about 2600 kcal/d for men and 1900 kcal/d for female, though these estimates vary with body size and activity level

Caloric requirement

TEE = REE + Stress Factor + Activity Factor

Rest Energy Expenditure Adults (18-65) 20-30 kcal/kg Elderly (65+) 25 kcal/kg For burns Patients 30-35kcal/kgOther factors: Pregnancy: Add 300 kcal/day Lactation: Add 500 kcal/day Obese or Super obese 15-20 kcal/kg

Stress factorperitonitis + 15%• soft tissue trauma + 15%• fracture + 20%• fever (per oC rise) + 13%• Moderate infection + 20%• Severe infection + 40%• <20% BSA Burns+ 50%• 20-40% BSA Burns + 80%• >40% BSA Burns+ 100%

Carbohydrate requirements Requirement 2g/kg/day 1grams=5kcal/g 40-50 percent of total nutrition Generally, because glucose is an essential

tissue fuel, glucose and amino acids are provided parenterally until the level of resting energy expenditure is reached. Fats are added thereafter

Fat requirements Requirement 3 g/kg/day 1 gram= 9kcal/g 30-40 percent of nutrition Liver can synthesize most fatty acids, but

humans lack the desaturase enzyme needed to produce n-3 and n-6 fatty acid series. Therefore linoleic acid should constitute at least 2% and linolenic acid at least 0.5% of daily caloric intake to prevent essential fatty acid deficiency

Protein requirements The standard enteral and parenteral

formulas contain protein of high biological value and meet the requirements for the eight essential amino acids

Protein or nitrogen balance provides a measure of feeding efficacy of PN or EN

Nitrogen balance

Nitrogen Balance = N input - N output

6.25 g protein provides 1 g of nitrogen as 100grams contains 16 g nitrogen

N input = (protein in g / 6.25) N output = 24h urinary urea nitrogen + non-urinary N

losses

+4 to + 6: Net anabolism +1 to - 1: Homeostasis -2 to – 1: Net catabolism

fluid requirements

ESTIMATING ADULT FLUID REQUIREMENTS By caloric intake : 1ml/calorie Example: 1800 calorie diet = 1800 calories

x 1ml= 1800ml By body weight and age : average

requirement is 30 ml/kg/d 16-55 years 35 ml/kg/d 56-65 years 30 ml/kg/d > 65 years 25 ml/kg/d

Electrolyte daily requirement Sodium 70 – 100 mEq/day Chloride 70 – 100 mEq/day Potassium 70 – 100 mEq/day Calcium 10 – 20 mEq/day Magnesium 15 – 20 mEq/day Phosphorus 40-60 mEq/day Acetate 0 – 60 mEq/day

Daily Parenteral Trace Element Supplementation

Zinc 2.5-4 mg Copper 0.5-1.5mg Chromium 10-15 mcg Selenium 20-60 mcg Manganese 150-800 mcg

Administration of TPN Introduction of TPN should be gradual. For

example, approximately 1,000 kcal is provided the first day. If there is metabolic stability (i.e., normoglycemia), this is increased to the caloric goal over 1 to 2 days.

TPN solutions are delivered most commonly as a continuous infusion. A new 3-in-1 admixture bag of TPN is administered daily at a constant infusion rate over 24 hours. Additional maintenance intravenous fluids are unnecessary, and total infused volume should be kept constant while nutritional content is increased

DISCONTINUATION OF TPN Discontinuation of TPN should take place when

the patient can satisfy 75% of his or her caloric and protein needs with oral intake or enteral feeding.

To discontinue TPN, the infusion rate should be halved for 1 hour, halved again the next hour, and then discontinued.

Tapering in this manner prevents rebound hypoglycemia from hyperinsulinemia.

It is not necessary to taper the rate if the patient demonstrates glycemic stability

Complications of parenteral nutrition MECHANICAL COMPLICATIONSAir embolism pneumothorax hemothoraxCardiac tamponadeInjuries to arteries and veinsInjury to thoracic duct Brachial plexus injury

METABOLIC COMPLICATIONS

Early or nutrient related hyperglycemia hypoglycemia hyperlipidemia refeeding syndrome

late or related to long term administration hepatic dysfunctionSteatosis, steatohepatitis, lipidosis, cholestasis,

cirrhosis biliary complications: acalculous cholecystitis, Gb

sludge, cholelithiasisMetabolic bone disease: osteomalacia, osteopenia

INFECTIONS: Catheter related sepsis is most common

life threatening complication Causes: staph epidermidis and staph

aureus, enterococcus, candida, E coli, pseudomonas, klebsiella etc in immunocompromised pts

Refeeding syndrome Severe electrolyte and fluid shifts that may

result from refeeding in severe malourished patients undergoing refeeding.

Patients at risk are alcoholics with malnutrition, anorexics

Hypophosphatemia is the hallmark of refeeding syndrome due to shift from fat to glucose metabolism.

Hypocalcemia and hypomagnesemiaThese can result in arrhythmia, confusion, coma, tetany, death.

• Treatment involves matching intake with requirements and avoiding overfeeding.

• Hypophosphtemia, hypomagnesemia requires treatment

• Thank you