36- parenteral & enteral feeding

Parenteral & Enteral Feeding

Aim of Nutritional Support

To ensure that the nutritional requirements are met in patients at risk of malnutrition, by the most appropriate route in a way that minimizes complications

Definition

Parenteral feeding: the provision of all nutritional requirements by means of IV route without the use of the GIT

Enteral feeding: delivery of nutrients into the GIT; either by standard oral intake or by direct administration into the stomach or a small intestine via a feeding tube

[Nutritional requirements: macronutrients, carbohydrates, fat, proteins, vitamins, trace elements, electrolytes & water]

Enteral Feeding

When possible, enteral feeding is preferred as a nutritional support, why?

Because it maintains gut mucosal integrity, protects against mucosal atrophy & reduces complications.

Enteral Feeding

Types:1. Sip feeding2. Nasogastric tube3. Gastrostomy4. Jujenostomy

1. Sip Feeding

By using small amounts of special formula Indicated in patients who can take fluids only (in

case of weakness in the mouth or the mastication muscles)

2. Nasogastric Tube

Fine bore tube (1mm) inserted into the stomach via the nose

Indicated in patients:1. Unable to swallow2. With CVA3. In coma4. In ICU

2. Nasogastric Tube[cont]

Intact gag reflex is a must in case of using this type of feeding

Good gastric peristalsis is a must (to prevent gastric stasis which can lead to gastric ulceration)

• How to check for peristalsis? By motility study; where a specific amount of

normal saline is administered into the stomach. After 2 hours, suction from the stomach is done, to compare both amounts.

(if the amount after suction was the same as the administered one, then there’s gastric stasis)

2. Nasogastric Tube[cont]

Disadvantages:• Nose irritation, ulceration & pressure necrosis• Offensive in conscious or semi-conscious patients• Duration limited; used for maximum of 2 months• Gastroesophageal reflux & aspiration (due to the

incomplete closure of esophageal sphincter in the presence of NG tube)

3. Gastrostomy

Tube inserted directly to the stomach through the abdominal wall

PEG [percutaneous endoscopic gastrostomy]: insertion of the tube by endoscope, used nowadays instead of open surgery

Good evacuation (good peristalsis) is also needed here, which can be confirmed by motility study

2. Gastrostomy[cont]

Indicated in:• Obstructed GI tract before the stomach (tumors in

oropharynx or lower esophagus)• Loss of peristalsis due to neuromuscular disorder• Need for nutritional support for long time (e.g: head

trauma, coma)

4. Jujenostomy

Post-pyloric feeding decreases risk of aspiration but difficult to place

Over distention could result from flooding of GIT by feeding

Indicated in:• Gastric obstruction (advanced gastric CA)• Major resection of upper GIT, like whipple procedure

(pancreaticoduodenectomy & gastrojejunostomy)

Complications of Enteral Feeding Tube-related: malposition, displacement, blockage,.. GI: diarrhea, nausea, vomiting, abdominal cramps,.. Metabolic: electrolyte disorders, drug interactions,.. Infective: handling contamination, endogenous,..

Total Parenteral Nutrition

Indications:1. Obstruction2. Short bowel syndrome3. Inflammation4. Fistula5. Inability to cope


Indications:1. Obstruction• Irremovable advanced tumors; e.g lymphoma• Pancreatic tumor: causes malabsorption &

obstruction


2. Short bowel syndrome (<1m of small intestine) A disorder clinically defined by malabsorption, diarrhea,

steatorrhea, fluid & electrolyte disturbances and malnutrition caused by loss of large segment of small intestine

Causes :- Mesenteric ischemia: superior mesenteric embolism

if left untreated for 5 hrs may lead to gangrene & resection.

- Volvulus neonatorum: bowel twisted around itself, which is treated by resection

- Crohn’s disease: recurrent surgical resection of the bowel


3. Inflammation Ulcerative colitis & crohn’s disease; TPN used to rest

the bowel


4. Fistula Fistula in the upper GIT Causes leak of pus, feces or bowel contents (gastric

juice, bile, enzymes, etc..) Managed conservatively & need 6 wks to improve

by using TPN to rest the bowel


5. Inability to copeIn cases of increased catabolic rate where the bowel can’t compensate the body demand, especially proteins:

- Sever sepsis.- Extensive burning.


How to perform TPN?Through the central line access:

1- Femoral V: rarely used, because it’s low and away from the heart

2- Internal jugular V: commonly used in anesthesia3- Subclavian V: commonly used


Why central not peripheral? Because the nutrition used is hyperosmolar, so:

- If peripheral access causes irritation, inflammation & thrombosis due to poor flow If complicated, it can’t be easily washed by saline because of the narrow lumen of peripheral veins

If central access Does not cause irritation due to high blood flow If complicated, can be easily washed out by saline


How to insert an IV central line?1. Supine position & head down (to congest neck

veins)2. Local anesthesia below the clavicle3. By a wide bore needle (1mm) make incision in the

inferior surface of clavicle4. Insert a cannula (backward medially & downward)

until blood comes out5. Introduce a catheter to reach SVC6. Fix the line by stitch


During the procedure: patient is asked to hold their breath to decrease risk of pneumothorax & air embolism

After the procedure: CXR is done to confirm the site of the catheter & to exclude pneumothorax


Complications of the procedure; injury of:1) Brachial plexus2) Subclavian artery (hematoma)3) Thoracic duct4) Phrenic nerve5) Superior vena cava6) Lungs (pneumothorax)7) Cardiac muscles


Complications of TPN:1) Line infection2) Fatty infiltration to the liver3) Hyper-osmolarity4) Re-feeding syndrome: metabolic disturbances that

occur as a result of reinstitution of nutrition to patients who are malnourished

5) Insulin rebound phenomenon (somogyi syndrome)

Infection TPN requires a chronic IV access for the solution to run through,

and the most common complication is infection of this catheter. Infection is a common cause of death in these patients, with a mortality rate of approximately 15% per infection, and death usually results from septic shock]

Blood clots Chronic IV access leaves a foreign body in the vascular system, and

blood clots on this IV line are common.] Death can result from pulmonary embolism wherein a clot that starts on the IV line but breaks off goes into the lungs.

Patients under long-term TPN will typically receive a periodic heparin flush to dissolve such clots before they become dangerous.

Fatty liver and liver failure Fatty liver is usually a more long term complication of TPN, though

over a long enough course it is fairly common. The pathogenesis is due to using linoleic acid (an omega-6 fatty acid component of soybean oil) as a major source of calories.

http://en.wikipedia.org/wiki/Parenteral_nutrition#cite_note-Mollitt-10

http://en.wikipedia.org/wiki/Pulmonary_embolism

http://en.wikipedia.org/wiki/Heparin

Hunger Because patients are being fed intravenously, the subject does

not physically eat, resulting in intense hunger pangs. The brain uses signals from the mouth (taste and smell), the stomach/G.I. Tract (fullness) and blood (nutrient levels) to determine conscious feelings of hunger. In cases of TPN, the taste, smell and physical fullness requirements are not met, and so the patient experiences hunger, despite the fact that the body is being fully nourished. In cases where the patient eats food despite the inability, they can experience a wide range of complications.

http://en.wikipedia.org/wiki/Hunger

http://en.wikipedia.org/wiki/Mouth

http://en.wikipedia.org/wiki/Taste

http://en.wikipedia.org/wiki/Olfaction

http://en.wikipedia.org/wiki/Stomach

http://en.wikipedia.org/wiki/Human_gastrointestinal_tract

http://en.wikipedia.org/wiki/Blood

http://en.wikipedia.org/wiki/Nutrient


How to give nutrition by TPN?Normal body need: Fluid: 30-40 mL/kg/day Calories: 30-40 kcal/kg/day Nitrogen: 0.15-0.2 g/kg/day Na: 100mmol/day K: 80mmol/day


Example A patient who weighs 70 Kg with fistula & fever 10

days post-op.. How to calculate the need?


Fluids70x40 = 2800 mL/day- An amount of fluid is lost by the fistula; so we add an

amount of fluid in order to compensate +1000 mL/day- Another amount must be added because of fluids lost in

sweating (he’s feverish) +200 mL/day

2800+1000+200=4000 mL/day

[sweating, fistula, diarrhea, vomiting & drain all cause fluid loss]


Calories:70x40 = 2800 kcal/day- He has sepsis & post-op stress, which causes a loss of

more calories, so to compensate +1200 kcal/day

2800+1200 = 4000 kcal/day


Nitrogen:70x0.2 = 14 g- Due to increased catabolism (due to sepsis), this

needs to be compensated + 7 g

14+7 = 21 g


How to give those nutrients as a source of energy? Carbohydrates 50% Protein 15% Fat 35%


Glucose WaterWe have many forms: 5%, 10%, 25%, 50%, 75%(1 g 4 kcal)

- 5% form contains 50 g/L so 200 kcal/L- 50% form contains 500 g/L so 2000 kcal/L

Our patient needs 4000kcal/day, this can be achieved by:20 L/day of 5% form or 2 L/day of 50% formSo 50% is better to be used in this case


NitrogenDifferent forms: 3%, 5%, 10%, 14% 14% form contains 14 g/L

Our patient needs 21g, so 1.5 L of 14% form can be given in this case


LipidDifferent forms:(1g 9kcal) - 10% form contains 100 g, so 900kcal/L[Not given daily, because it causes allergic reaction & interference with coagulation factor and it’s expensive]

ElectrolytesNormal saline or ringer lactate


General instructions: TPN must be given by drips, one bottle with fixed gradual rate(1st day 2.5.. 2nd day 3.5L.. 3rd day 4.5L..) Nutrients must not be given at once, this may cause

hyperglycemia & rebound insulin phenomena Pt must be weighed daily, increment of 300 g or more this is

over feeding, so decrease doses KFT & LFT weekly Electrolytes & glucose level daily (for metabolic complication) In case of sepsis: drain the cath, culture, & change site of cath

Thank You

36- parenteral & enteral feeding

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