SURGICAL NUTRITION

Professor Magdy Amin RIAD

Professor of Otolaryngology. Ain shames University

Senior Lecturer in OtolaryngologyUniversity of Dundee

Nutritional assessment

• Clinical assessment – Weight loss – 10% =mild malnutrition – 30% = severe malnutrition – Body mass index

• Anthropometric assessment – Triceps skin fold thickness – Mid arm circumference – Hand grip strength

• Blood indices – Reduced serum albumin, prealbumin or transferrin – Lymphocyte count

• No index of nutritional assessment shown to be superior to clinical assessment

Methods of nutritional support

• Use gastrointestinal tract if available

• Prolonged post-operative starvation is probably not required

• Early enteral nutrition reduced post-operative morbidity

Enteral feeding

• Prevents intestinal mucosal atrophy

• Supports gut associated immunological shield

• Attenuates hypermetabolic response to injury and surgery

• Cheaper than TPN and has fewer complications

Polymeric liquid diet

• Short peptides, medium chain triglycerides and polysaccharides

• Vitamins and trace elements

Elemental diet

• L-amino acids, simple sugars

• Expensive and unpalatable

• High osmolarity can cause diarrhoea

Enteral feed

• Enteral feed can be taken orally or by NGT Nasoenteral tube - usually fine bore 

• Long term feeding can be by:

• Surgical gastrostomy, jejunostomy

• Percutaneous endoscopic gastrostomy

• Needle catheter jejunostomy

• Rate of infusion – often started at low rate and increased

• Strength of initial feed – often diluted and strength gradually increased

Complications of enteral feeding

• Malposition and blockage of tube

• Gastrooesophageal reflux

• Feed intolerance

Enteral Therapy

1. Continuous: delivery of formula at a designated rate over a 24-hour period via an enteral feeding pump.

2. Interval: delivery of a designated volume of formula 6 times per 24-hour period via an enteral feeding pump at 300 cc per hour

EQUIPMENT

• 1. Enteral feeding set with bag

• 2. Formula

• 3. Graduated cylinder

• 4. Irrigation container

• 5. 60 cc syringe with catheter adaptor

• 6. Enteral feeding pump

PROCEDURE

• 1. Clamp nasogastric tube as ordered by physician. This will be done when bowel sounds are present.

• 2. Assess for complaints of nausea. If nausea occurs, unclamp the tube and attempt to aspirate gastric contents to prevent vomiting. Reclamp when nausea subsides. The tube should be clamped and the patient free of nausea 1 hour before initiating a feeding.

PROCEDURE

• 3. After all feeding tube placements and/or adjustments, a radiograph is usually obtained to verify proper location of tube prior to initiating feedings. Verification must be approved by physician.

• 4. Explain procedure to patient. Elevate head of bed to a sitting position (45°). Maintain upright position during continuous and interval feedings and for 30 minutes after interval feedings.

• 5. Wash hands thoroughly.

Prior to feedings:

a. Confirm that a radiograph has been reviewed to verify proper placement of tube before initiating feeding.

b. For subsequent feedings, assess tube position (eg, absence of coiling in mouth, length of tube from nose to inlet).

Initiation and progression of feedings:

a. Initiate feedings with D5W at 100 cc per hour x 2 hours per feeding pump. Wait 1 hour and assess residual. If >100 cc, recheck in 1 hour. Repeat as needed.

b. If feeding tolerated, start full-strength isotonic formula at 50 cc per hour per feeding pump. NOTE: If hypertonic formula is used, refer to Precautions, Considerations and Observations for information concerning initiation and advancement of feeding.

Initiation and progression of feedings:

c. Advance the rate of feeding 25 cc per hour every 12 hours as tolerated until desired rate is achieved (usually 75 to 100 cc per hour). Do not exceed desired rate recommended by dietitian.

d. Convert to interval feedings 48 hours after desired continuous rate is achieved. Establish interval feeding schedule by dividing 24-hour volume into 6 feedings. Administer interval feeding per feeding pump at 300 cc per hour

8. Gastric residual should be assessed every 4 hours (see 2 under Precautions, Considerations and Observations).

9. Dilute medications with 30 cc water and administer a few minutes apart if patient is taking more than 1 medication

Flush the feeding tube to clear formula and medications from the tube and ensure patency:

a. Flush with 50 cc tap water prior to administration of medications or interval feedings.

a. Flush with 50 cc tap water after medication administration or interval feedings.

c. Flush with 50 cc tap water every 4 hours before hanging new formula with continuous feeding.

d. The dietitian will make recommendations for additional water requirements as indicated.

specific intolerance problems: a. Nausea, vomiting, fullness, or

cramping:

(1) Continuous feeding: stop feeding for 1 hour. Resume feeding at the last tolerated rate for the next 12 hours and then increase.

(2) Interval feeding: stop feeding and hold until next scheduled feeding.

Heartburn:

• (1) Do not stop feeding.

• (2) Contact physician for antacid order (preferably Maalox).

Flatulence:

• (1) Do not stop feeding.

• (2) Increase physical activity/ambulation.

Liquid stools (3 or more totaling 500 cc or greater per 24 hours):

(1) If diarrhea occurs within 48 hours after feedings are initiated:

(a) Change to sterile water at 50 cc per hour for 12 hours, then resume formula feeding at 50 cc per hour and advance per protocol.

(b) If no improvement within 24 hours, consult physician/dietitian for further recommendations.

Liquid stools (3 or more totaling 500 cc or greater per 24 hours):

(2) If diarrhea occurs after 48 hours from initiation of feedings, consult physician for antidiarrheal medication:

(a) Imodium (loperamide) 4 mg initially, followed by 2 mg after each unformed stool (maximum 16 mg per day) or

(b) Lomotil (diphenoxylate with atropine sulfate) 5 mg, 3 to 4 times per day

(c) If no improvement within 24 to 48 hours, consult physician/dietitian for further recommendations.

• The most reliable indicator of proper tube placement is a radiograph, followed by pH and aspirate color, with auscultation a poor fourth. Auscultation alone is unreliable; sounds may be heard with lung placement, as well as esophageal, gastric, or intestinal placement

Check gastric residual if feeding intolerance occurs (nausea/fullness):

• a. Continuous feedings: (1) If residual is greater than 2 hours of present rate, hold the feeding and recheck in 1 hour. Resume feeding when amount is less than 2 hours of present rate, otherwise continue to check hourly. (2) When the desired volume of feeding is achieved, discontinue checking residual unless feeding intolerance occurs.

Check gastric residual if feeding intolerance occurs (nausea/fullness):

• b. Interval feedings: • (1) If more than 100 cc of the previous feeding is

aspirated, hold the feeding and recheck in 1 hour. If aspirate remains more than 100 cc, hold feeding until next scheduled time. (2) When residuals are less than 100 cc for 24 hours, discontinue checking residual unless intolerance occurs.

• Formula feedings should be out of refrigeration no longer than 4 hours.

• 4. This procedure primarily pertains to gastric feedings. For duodenal or jejunal feedings, consult the dietitian to determine formula selection and maintain continuous administration rate.

• 5. If the patient is starting on interval feedings and shows any signs of intolerance, consider returning to continuous feedings.

• 6. Avoid stopping continuous feedings during bathing, ambulation, or while assisting patient to bathroom.

• 7. Consult physician and dietitian to establish insulin dose and dietary requirements for diabetic patients.

• 8. Surgical patients on tube feedings should be weighed daily through postoperative day 5, then 3 times a week.

• 9. Consult the dietitian for special formulas, electrolyte imbalance, signs/symptoms of dehydration or intolerance to formula feedings.

• 10. Enteral feeding sets are changed every 24 hours. Label with date and time opened and the patient’s name.

• 11. Interval feeding bags should be rinsed after each feeding.

• 12. Change enteral irrigation sets every 24 hours and change water in set every 8 hours.

• 13. Patients on enteral feedings will be evaluated by the dietitian for free water requirements, protein, and calorie needs.

• 14. If hypertonic formula is administered: • a. Initiate half-strength formula at 25 cc

per hour. b. Increase strength every 12 hours until full strength is achieved (ie, half strength, three-quarters strength, full strength).

• c. After full strength is achieved, increase rate 25 cc per hour every 12 hours until desired rate is met.

• 15. If a patient has been taking a diet by mouth, it is not necessary to initiate feeding with D5W.

• 16. If tube feedings are withheld for reasons other than general anesthesia (eg, diagnostic tests), full-strength feedings may be resumed without the need for gradual progression of feeding.

• 17. When a patient is discharged on tube feedings, adjust schedule to 5 interval feedings per day by gravity drip

Parenteral nutrition

• Intestinal failure = ‘A reduction in functioning gut mass below the minimal necessary for adequate digestion and absorption of nutrients’

• Useful concept for assessing need for TPN

• Can be given by either a peripheral or central line

Indications for total parenteral nutrition

• Absolute indications – Enterocutaneous fistulae

• Relative indications – Moderate or severe malnutrition – Acute pancreatitis – Abdominal sepsis – Prolonged ileus – Major trauma and burns – Severe inflammatory bowel disease

Peripheral parenteral nutrition

• Hyperosmotic solution

• Significant problem with thrombophlebitis

• Need to change cannulas every 24- 48 hours

• No evidence to support it as a clinically important therapy

• Composition - 12g nitrogen, 2000 Calories

Central parenteral nutrition

• Hyperosmolar, low pH and irritant to vessel walls • Typical feed contains the following in 2.5L • 14g nitrogen as L amino acids • 250g glucose • 500 ml 20% lipid emulsion • 100 mmol Na+ • 100 mmol K+ • 150 mmol Cl - • 15 mmol Mg2+ • 13 mmol Ca2+ • 30 mmol PO42- • 0.4 mmol Zn2+ • Water and fat soluble vitamins • Trace elements

Complications of subclavian and jugular central venous lines

• 10% of central lines develop significant complications• Problems of insertion

– Failure to cannulate – Pneumothorax – Haemothorax – Arterial puncture – Brachial plexus injury – Mediastinal haematoma – Thoracic duct injury

• Problems of care – Line and systemic sepsis – Air embolus – Thrombosis – Catheter breakage

Monitoring of parenteral nutrition

• Feeding lines should only be used for that purpose • Drugs and blood products should be given via separate

peripheral line • 5% patients on TPN develop metabolic derangement • Nutrition should be monitored:

– Clinically – Weight – Biochemically twice weekly – FBC, U+Es, LFTs, – Mg2+, Ca2+, PO42-, Zn2+ – Nitrogen balance

• Blood cultures on any sign of sepsis

Metabolic complications of parenteral nutrition

• Hyponatraemia

• Hypokalaemia

• Hyperchloraemia

• Trace element and folate deficiency

• Deranged LFTs

• Linoleic acid deficiency

Approximate indications for an 80 kg patient

after surgery

• Dosage: 25 - 30 kcal/kg KG/day

• Polytrauma, sepsis, Burns < 40% :

30 - 35kcal/kg/day

Polytrauma with complications, prolonged sepsis, Burns > 40%

: 35 - 45 kcal/kg/day