Nutrition

Assessment Body Weight Serum Albumin Skin Fold Thickness

Malnourishment BMI - body mass index < 18.5 (weight in kilograms divided by the square of the height in metres) Has lost more than 10% unintentional weight in 3-6 months BMI < 20 and he or she has lost 5% of his or her weight in 3-6 months

Nutritional Support Patients starved for five days or patients unlikely to eat in a period of five days are at risk of malnourishment. Patients with malabsorption disorders, nutrient losses, and increased nutrient requirements also qualify for nutritional support.

Nutritional Requirement Average nutritional prescription 25-35 kcal/kg/day total energy, 0.8-1.5 g protein (0.13-0.24 g nitrogen)/kg/day, 30-35 ml fluid/kg, electrolytes, minerals, micronutrients, fibre.

In patients with serious comorbidity, the prescription can be designed to provide 50% of the nutritional needs initially and then build up to a full prescription within 24-48 hours.

Non-Protein Calorie Requirement 20 cal/Kg/d – Unstressed, Well nourished 25 cal/Kg/d – Mild Stress (Elective Surgery 30 cal/Kg/d – Moderate Stress (Infection, Trauma) 35 cal/Kg/d – Maximal Stress (Major Surgery, Burns, Severe Sepsis)

Protein Unstressed, Well nourished – 0.6-1gm/Kg Postoperative patients – 1.5-2gm/Kg/d Highly Catabolic Patients – 2gm/Kg/d Non-Protein Calorie : Nitrogen = 150:1 1gm Nitrogen = 6.25gm Protein ARF – 0.5gm/Kg/d Dialysis – 1-2gm/Kg/d

Nitrogen Balance Nitrogen Intake = Protein Intake/6.25 Nitrogen Output = 24hr Urinary Urea Nitrogen + 4 Nitrogen Balance = Nitrogen Intake – Nitrogen Output Moderate Stress – Negative balance 0-5 Severe Stress – Negative balance > 5

Oral Nutritional Support The addition of evaporated milk to soup or butter to vegetables can raise the nutrient content of food. Fortified drinks based on milk or juice provide about 10 g protein and 200-300 kcal (840-1300 kJ). Glucose polymers, liquid fat, or protein can also be used to increase the nutritional content of food.

Enteral Feeding Preferred route of feeding if possible To be started within 1-2weeks Contraindications - - GI aspirate >600ml/24hr - - Massive GI Bleed Mild bleeding resolve with enteral feeding Enteral nutrition does not exacerbate mild lower intestinal bleeding

Enteral Feeding Poor Tolerance – Vomiting - Residue > 150 after 4 hours 1/3rd of hrly feeds - Worsening of Diarrhoea Risk of Aspiration – Elevate head during feeding & 30 min after feeding Gastrotomy/Jejunostomy – Prolonged tube feeding > 30d Complications – Loose motions (Inf., Osmotic) - Tube dislodgement - Aspiration

Enteral Nutrition Enteral nutrition is cheaper and probably safer, but may be associated with significant complications. It may frequently result in under-nutrition, unless protocols are used to avoid slow initiation and the too ready cessation of feeds. Acceptance of gastric residual volumes of 200-250 ml and the early use of pro-kinetics are key elements of such protocols. Head-up tilt of at least 45° should be used whenever possible to facilitate EN. Aspiration is a possible risk with naso-gastric feeding,

Enteral Nutrition In acute haemorrhagic pancreatitis, the use of EN has been reported as being beneficial and the need for 'pancreatic rest' for such patients has been challenged. The naso-gastric route has also been confirmed as being safe and suitable for these patients

Conversion Factors 1 gm parental Glucose = 3.4 cal 1 gm enteral glucose = 4 cal 1 gm Fat = 9 cal 1 gm Nitrogen = 6.25 gm Protein 1 gm Nitrogen loss = 30 gm lean body mass lost 10% Amino acid = 10 gm protein/l

Parenteral Nutrition CARBOHYDRATE 50-60% calories Minimum 500 cal for Cerebral requirement Adjust dose to keep Blood Sugar < 110mg > 12.5% Dextrose to be given by Central line Maximum glucose that can be effectively metabolized - 6mg/Kg/min (max 1500cal)

Parenteral Nutrition LIPID 30-40% of calories 20% Lipid = 1000 cal/l Avoid 3 way Use filter with air vent Change Infusion set after infusion Rate of Infusion – 50ml/hr (15 drops/min)

Electrolyte Requirement Sodium – 30 mEq/l Potassium – 20 mEq/l Phosphate – 0.2 mMol/Kg/d Magnesium – 0.35-0.45 mEq/Kg/d Calcium – 8-10 mEq/d

Vitamin Requirement Water soluble vitamins required daily Fat soluble vitamins 1-2 times/week Vitamin K – 10mg IV weekly Folic Acid – 1 mg daily Vitamin B12 – 1000mcg IM 1-2 weeks (once per month in chronic TPN)

Trace Elements 1 amp per day Zinc 10 mg/d extra in large wounds Chromium 1 mg/d in glucose intolerance

Monitoring Baseline blood tests should include Full blood count, Urea and electrolytes, Glucose, Magnesium and phosphate, calcium, Albumin, liver function tests, INR Iron, vitamin B-12, C reactive protein, zinc, copper, folate.

Monitoring Once stable, weekly monitoring should include full blood count, urea and electrolytes, glucose, magnesium, phosphate, liver function tests, international normalised ratio, calcium, albumin, and C reactive protein. Occasional tests should include iron, ferritin, zinc, copper, folate, and vitamin B-12.

Monitoring in TPN Electrolytes Glucose Triglycerides – to be measured 6hrs after stopping lipid infusion Urea

There is certainly consensus that enteral nutrition (EN) should be considered before the parenteral route (PN). However, PN may not be as harmful as often assumed.

Quantity of Support The 'underfeeding' frequently reported may provide a protective safety barrier. This has been shown in a US study, when patients who received between 33% and 65% of calculated requirements (according to American College of Chest Physician guidelines) had better outcomes in terms of mortality and duration of ventilation compared with those receiving greater than 65%.

Quantity of Support Failure to deliver at least 25% of calculated requirements is associated with significant increases in infection and mortality The National Institute for Clinical Excellence (NICE) recently recommended that PN should be limited to a maximum of 50% of the calculated requirements for the first 48 h after initiation. Although calculated requirements for calorific support using the Schofield method may exceed 2000 kcals per 24 h, it will only rarely be appropriate to deliver such a quantity.

Evidence B plus Enteral nutrition preferred to standard care (nothing by mouth) Early parenteral nutrition (<24 hours) preferred to delayed (>24 hours) enteral nutrition.

Evidence B Early enteral nutrition (<24 hours) preferred to delayed (>24 hours) enteral nutrition; Parenteral nutrition preferred to standard care (intravenous glucose); Early enteral nutrition (<24 hours) preferred to parenteral nutrition; Postpyloric feeding preferred when gastric feeding not tolerated; Prokinetics preferred when gastric feeding not tolerated;

Evidence B Enteral nutrition supplemented with parenteral nutrition recommended if 80% of goals are not met by 72 hours with enteral nutrition alone (after consideration of postpyloric feeding, prokinetics, or both Protocolized management of diarrhea Protocolized definition of intolerance of enteral nutrition, which includes gastric residual values greater than 200 mL.

Evidence B minus Instead of standard parenteral nutrition, parenteral nutrition with glutamine may be considered; Glutamine may be beneficial in select patients, based on review of each constituent randomized controlled trial as well as clinical judgment.

Glutamine This helps to maintain gut mucosal integrity and cellular immune function. As a consequence, translocation of enteric bacteria and endotoxins is reduced and infective complications less frequent. A meta-analysis carried out by Heyland et al. The relative risk (RR) for mortality in this study was 0.78 (95% CI 0.59-0.97); an almost identical result was shown for infective complications RR=0.76(0.59- 0.98).

Arginine Arginine supplementation is not recommended for septic ICU patients but, because of its beneficial effects on T lymphocyte function, it has been shown to reduce infective complications in elective general surgical patients.

Fish Oils. Omega-3 fatty acids - the evidence base is limited.

Hepatic Failure Fluid Restriction (1500ml/d) Protein – 1-1.3gm/Kg Branch chain amino acids Increased losses of potassium, magnesium, & zinc 50% carbohydrate & 50% fats Vitamin A, D, & B complex supplements

Acute Renal Failure PD fluid contains glucose PD removes amino acids – 40-60gm/d HD removes amino acids – 3-5gm/hr Protein requirement – 1gm/d + 4gm/hr HD Fluid restriction Calorie density – 2cal/ml PN - 35%dextrose, 20% lipid Sodium – 40-70 mEq/d Trace elements & vitamins

Refeeding Syndrome Chronically malnourished (BMI < 19) Hypophosphatemia Hypomagnesemia Hypokalemia Volume Overload CCF Introduce TPN gradually

You are called for advice when a patient’s nasoenteral tube, used for giving feeds & drugs is blocked This is a common situation caused by incorrectly prepared drugs given through nasoenteral tubes. Nasoenteral tubes can kink and become blocked by nutritional residue, especially if tubes are too small. Checking for kinks and flushing the tube repeatedly with water resolves most blockages. Tubes that remain blocked, fall out, or cause discomfort should be replaced. If high residue feeds are needed, use larger diameter tubes.

You are asked to evaluate a patient with new onset diarrhoea after starting enteral feeds. Assess fluid balance. Cold formula, high infusion rates, hyperosmolar formula food, and bolus feeding can be responsible for diarrhoea in patients who have just started enteral feeds. Aim to deliver feeds at room temperature, and consider reducing the rate of feeds and volume. Isotonic feeds can also be considered. If malabsorption is the cause, elemental feed can be used. Lactose intolerance, infective causes, and drugs, for example, antibiotics and drugs that contain sorbitol, are differential diagnoses

A patient is complaining of nausea after starting enteral feeds If the patient has not opened the bowels recently he or she might have an ileus, in which case consider parenteral nutrition. Examine the enteral tube to ensure that it is correctly sited. Evaluate the nutritional prescription-is the volume too high? If so reduce the feed volume, and consider a more concentrated feed. If the feed is too concentrated this can trigger nausea. Slowing the infusion rate and ensuring feeds are delivered at room temperature improves symptoms. Patients can develop sickness if they are lactose intolerant, in which case a lactose deficient formula is needed. Prokinetic drugs can reduce gastric emptying. Don’t forget to consider an infective cause of symptoms; even the feed can be a source of infection.

You are called to see a patient who has aspirated on his or her enteral feed Once you have resuscitated the patient, you need to consider the position of the patient. By sitting the patient up at 30°, the risk of aspiration is reduced. Reducing the bolus volume and rate can also help. Consider prokinetic drugs Replace the tube if displaced.