Nutrition Flashcards
What are the two aspects of malnutrition?
- Decreased intake absorption
- Increased expenditure losses
Nutritional screening: ABCD
Anthropometric data (weight loss in past 6w, height)
Biochemical (electrolyte, albumin)
Clinical (disease state, medications, physical exam)
Diet (nutritional intake in past week)
What happens after screening?
- Nutritional screening
- Refer to nutritional specialist/dietitian
- Nutritional assessment (ONS / EN / PN / Palliative care)
- Formulation of nutritional regime
Calculation of Estimated Energy Requirements (EER)
- Indirect calorimetry
- Weight based: 25-35kcal/kg
- Predictive equations: estimates basal metabolic rate only, multiple by stress factor and physical activity
Calculation of Protein Requirements (EPR)
EPR = 0.8-1.5g/kg/day
In different disease states:
- Healthy adult: 0.8
- Trauma/burn/surgery: 1.5-2
- Sepsis/critical illness: 1.5-2.5
- CKD (ND): 0.6-0.8
- CKD (HD/PD): 1.2
- CKD (CRRT): 2
Based on guidelines, when to start EN for adult oncology patients?
- Use EN in adult oncology patients who have solid tumors, are unable to receive oral intake, or >60-75% of goal nutrient intake, and who present with mod-severe malnutrition
- Use EN in patients unable to tolerate >60% of energy and proteins by mouth despite oral supplementation for >7-14 days
Enteral access devices and their pros
- Pre-pyloric
- More physiologic
- Higher tolerance to bolus feeding
- Higher tolerance to higher osmolarity
- May be used for venting to minimize aspiration risk
- Post-pyloric
- Less discomfort due to smaller bore
- Lower aspiration risk
- However, higher risk of tube clogging
- However, lower tolerance to hyperosmolar feeds (isoosmolar ~300mOsmol/L)
Pros vs Cons of Bolus vs Continuous
Bolus
- More convenient
- More physiologic
- However, higher risk of aspiration
- However, less tolerated (bloatedness, abdominal discomfort)
Continuous
- Lower risk of aspiration
- Better tolerated
- But less tolerated
Types of EN
- Modular
- Semi-Elemental / Elemental
- Polymeric
- Immune-modulating / Disease-specific
Drug-nutrient interaction with EN, how to mitigate/prevent
NIL for bolus/intermittent
Continuous
- precipitation
- crudling/clamping of protein (in acid environment)
- decrease drug activity due to destroyed release profile of drug (if drug cannot be crushed) - sustained release/enteric coated
Mitigate/prevent:
- Stop feeding and flush feeding tube before and after drug administration
- Use therapeutic alternatives - tablets that can be crushed / solutions
Common complications with EN
- Occlusion of feeding tube (due to precipitation, adherence of highly concentrated feeds to inner walls, improper flushing technique)
- Tube migration
- Infections secondary to microbial contamination (do not add fluid into the feed, fluid should only be delivered through water flushes)
- Aspiration
- N&V
- Diarrhea / Constipation
- Refeeding
Monitoring parameters for pt on EN
- Tolerability of bolus (abdominal pain and discomfort, bloating, N&V, aspiration)
- Tolerance to EN (presence of undigested EN feeds in vomit/NG output/aspiration)
- Tolerability of osmolarity of feed (diarrhea)
- Refeeding (electrolytes)
- Fluid overload - intake, output
- Blood glucose levels
How to maximize tolerance to EN?
- Bolus => Continuous
- Pre-pyloric => post-pyloric
- Isotonic formula
- Prokinetic agent (Metoclopramide, Domperidone, IV Erythromycin) for N&V
- Elemental feeds for those with malabsorptive issue
Parenteral access device
- Peripheral
- Requires frequent resite every 72h
- Limited by concentration and osmolarity (~900mOsmol/L)
- Central
- Can accommodate large conc and osmolarity as quickly diluted by high blood flow
- Types: non-tunneled central venous catheter, tunneled central venous catheter, peripherally inserted central catheter, port-a-cath
*Non-tunneled not used for >2w due to high risk of infection
Composition of PN
All in elemental form (as no digestion takes place)
Different compositions of Amino acids + Dextrose + Lipid emulsion + Electrolytes
TPN (no fats) VS TNA (3 in 1)
PN regimen:
Break down of EER = EPR + Dextrose + Lipids
EPR: 1g/kg/day (for unstressed patients)
Fats: 20-30% of EER or 1g/kg/day
Dextrose/Carbohydrates: 50-60% of EER or 4-5mg/kg/min
Comment on stability and compatibility of PNs
Due to admixture of multiple elemental components,
- Stability: lipid emulsion may be unstable
- Compatibility: calcium and phosphates may precipitate, dextrose is acidic
Drug-nutrient interaction of PN, how to prevent/mitigate
- Not an issue if separate lumens
- Need to check stability and compatibility for Admixture/Y-site
Administration of incompatible drugs may cause:
- precipitation
- decrease drug activity
- phase separation of lipid emulsions
- toxicity
PREVENTION/MITIGATION
- Administer via separate cannula
- Stop feeding, flush access tube before and after drug administration; *check blood glucose levels to prevent hypoglycemia
Common complications of PN (device-related)
- Occlusion (precipitation, thrombosis, lipid residues) *heparin lock, proper flushing technique, change administration set q24h
- Catheter-related bloodstream infection *aseptic technique
- Mal-positioning
Common complications of PN (metabolic-related)
- Refeeding syndrome
- Hyper/hypoglycemia
- Fluid overload
- Metabolic bone disease
- IFALD (Intestinal-failure-associated liver disease) - cholestasis, fatty liver, inflammation due to LCT component
Refeeding syndrome management strategies
- Identify high-risk patients
- BMI <16, unintentional weight loss >15% in past 3-6m, little or no nutritional intake >10d, low levels of electrolytes
- BMI <18.5, unintentional weight loss >10% in past 3-6m, little or no nutritional intake >5d, hx of alcohol misuse, insulin, chemotherapy, antacids, diuretics
- Check baseline serum electrolytes
- Correct electrolyte deficiencies
- Start thiamine (vit B1) supplementation 100mg OD 5-7 days
- Initiate feeding at 40-50% of EER, slowly increase over next few days
- Continue to monitor electrolytes as feeding progresses, adjust amount of replacements as needed
Should we replete blood sugar levels before initiating PN?-
No, PO/EN/PN/IV dextrose can precipitate or worsen refeeding
What ethical principles are involved in making decisions regarding artificial nutrition?
These basic principles are (1) autonomy, respect the patient’s healthcare preferences; (2) beneficence, provide healthcare in the best interest of the patient; (3) nonmaleficence, do no harm; and (4) justice, provide all individuals a fair and appropriate distribution of healthcare resources.
