o Hypocaloric Feeding: Intentional administration of less than the patient’s predicted energy requirements puts them in a semi-starved state, requiring them to utilize fat stores as their energy source (see Protein)

- Protein o High Protein Feeding: Coupled with hypocaloric feeding,

this application encourages the utilization of fat stores as an energy sources while preserving muscle mass

- Method to this Madness: Hypocaloric High protein feeding has been proven to be beneficial in obese patients. Induction of a semi-starvation state helps reduce body fat, However, sufficient elevated protein intake is required otherwise there are severe risks associated with negative nitrogen balance

(11/20) Garofalo Lecture: Parenteral Nutrition Modes of Parenteral Nutrition (PN)

- TPN: Total Parenteral Nutrition o Highly concentrated dextrose+AA solutions (³900 mOsm/L) administered via Central venous catheter

- PPN: Peripheral Parenteral Nutrition o Less concentrated dextrose+AA solutions (<900 mOsm/L) administered via Peripheral venous catheter

- ~~~Enteral Nutrition (EN) are formulations administered through a feeding tube (discussed next lecture) Efficacy: PN versus EN

- Preference: EN is preferred over PN o EN Benefits: EN is more cost-effective and more convenient,

§ Better supports the viscera (hepatic protein synthesis and regulation of metabolic processes) § Helps to maintain functional gut mucosa

o EN Complications: EN is associated with less severe complications than PN - Emergency cases: Neither. With adequate hydration, patients may remain NPO for 5-7 days without AE

Parenteral Nutrition (PN) - Indications: Parenteral nutrition is indicated in patients unable to eat or absorb adequate nutrients via GI tract

o Massive Small Bowel Resection o Intractable Vomiting (Preg?) o Chronic Malabsorption o Severe Diarrhea (IBD)

o High output enterocutaneous fistula (GI tract and skin communication)

o Chemotherapy or radiation o Eating disorder

o Bowel Rest – Situations requiring avoiding the GI tract: Acute Pancreatitis (unable to tolerate post-pyloric EN), perforated GI tract, GI obstruction

o Critically ill patients: Hold PN for first 7 days unless NRS ³5 (Early EN (24-48h) if stable) o Major GI Surgery: Start preoperatively

- Components o Macronutrients

§ Dextrose: 10-35% § Fat; 10-20% § Crystalline AA (Standard)

o Micronutrients: § Electrolytes § Vitamins + Trace Minerals

o Water (Via Sterile water for injection)

- Peripherally Inserted Central Catheters (PICC): A PICC line may be inserted into the peripheral vein (basilica, cephalic, or brachial, and go into the superior vena cava. ~ Can handle higher osmolarities, less invasive than Central lines.

TPN PPN Duration > 1-2 weeks < 7-10 days Advantages Can handle hyperosmolar solutions (>900mOsm)

Higher Max [Dextrose] – Up to 35%, AA 10% Allows for fluid restriction if necessary

Less invasive (Specialty nurses may add on PICC line) Less complications

Disadvantages Invasive procedure (Pneumothorax) Greater infection risk More care for line maintenance

Limited by the osmolality (< 900mOsm) Maximum [Dextrose] = 10-12.5% Requires Larger volumes to meet caloric and protein needs (max 3000mL volume) Frequent IV site changes High incidence of phlebitis

PN Administration Techniques: Ok, so you are having trouble deciding between a TPN or PPN, well let’s make it more complicated, do you want a 3-in-1 or a 2-in-1? [2-in-1 = AA + Dextrose, Separate fat bag] [3-in-1 = All in one]

Categorical Comparison 2-in-1 3-in-1 Lines Requires 2 lines, more manipulation Only 1 line, less manipulation, easier

in home care settings Cost Cheaper More expensive Filter 0.22 micron filter, capable of

removing micro-organisms, but cannot fit fat through.

1.2 micron filter, only prevents passage of fungus and large particles. Things (lipid) start to aggregate!

Precipitate Cant see if spoiled or precipitate Cannot visualize precipitate PN Types of Infusion

- Continuous: This is the more commonly used method for hospitalized patients. Gives glucose throughout the day, which often suppressed patient appetite.

- Cyclic: This minimizes hepatotoxicity and provides the patient the opportunity to eat during the day, cycle the infusion at night. Thus, it is capable of, and mostly is used in the home-based care setting.

Designing a PN Regimen Step 1: Determine the patient’s fluid, calorie, protein requirements Step 2: Allocate 30% of calories for Fat! This will minimize hepatic complications, as it mimics daily intake (Unless contraindicated) Step 3: Calculate Kcal from protein Step 4: Calculate grams of glucose based on kcal left Step 5: Calculate %Dextrose and %Protein Step 6: Add Electrolytes, MVI, and Trace elements Monitoring: When compounding a TPN, we will be adding many micronutrients, it is critical to know:

- Glucose: q6 hours initially, then Qdaily later - Triglycerides: Weekly, this is to ensure the pt is

tolerating the fat emulsion o 12 hour infusion: Goal Tg< 300mg/dL

- Weight: Daily - Vital Signs Ins/Out = Every shift - LFT, CBC, Pre-albumin: 1-2qweekly - Electrolytes, BUN: Daily until stable.

Electrolyte Adjustments: Look at the trends of the labs, there are physiologic changes that occur throughout the day.

- Treat the pt not the numbers. Before making adjustments:

- Determine fluid status - Determine acid-base status - Note the abnormal values on daily reports - Note the trends over the past few days

Sodium: Consider hydration status first. Adjust as 0.5/day Potassium: Consider acid/base and renal status. 0.5/day Magnesium: Consider renal status and albumin level Phosphate: Consider renal status Calcium: Consider albumin level

Example Problem: 22yo male with a bowel resection 1 day ago, currently experiencing moderate protein deficiency is still NPO in the ICU. Dude has normal hepatic and renal function He is 180cm, 70kg, and IBW = 72kg Not Obese à Use ABW Step 1: 1 day post-op, use post-surgery calculation. Good organs Fluid: 40mL/kg/day • 70kg = 2800mL/day Calories: 25-30kcal/kg • 70kg = 1750-2100kcal Protein: 1.3-1.5g/kg • 70kg = 91-105g Step 2: 30% Fat calories. Pick the low end (don’t overfeed) 1750kcal•30% = 525kcal from fat.

- Inventory – we have 20% bags of fat, they are 2kcal/mL

- 525kcal/2kcal•1mL = 263mL from fat Remaining volume = 2800-263 = 2537mL remaining Step 3: Pick the higher end for proteins (preserve lean body mass) 105g Protein • 4kcal/g = A420kcal from protein Step 4: What is left for glucose? 1750kcal total – A420kcal protein – 525kcal fat = 805kcal dextrose Caloric density of dextrose = 3.4kcal/g. è 237g dextrose Steph 5: Dextrose: 237g/2537mL = Convert to g/100mL è 9.3% Protein: 105g/2537mL = Convert to g/100L è 4.1% Step 6: Add electrolytes MVI and trace minerals

Complications of PN: - Catheter-related: Pneumothorax, Catheter embolization, phlebitis, infection - Bloodstream Infections: Fat emulsions are the culprit! – they support gram(+) and gram(-) bacteria/fungi

Elevation in LFT: The biggest complication with PN is the long-term rise in LFT. The liver starts to get funky, not appreciating having to utilize all the administered glucose.

- Mild elevations (<3x ULN) in hepatic enzymes (AST, ALT) is common during the first 2-4 weeks of therapy - Severe elevations (>5x ULN) will require intervention. - Cx: Overfeeding is the most likely cause of LFTs. Overfeeding will cause excess insulin release, resulting in

excess conversion of dextrose to fat. May lead to hepatotoxicity o Solution: Give the liver a break, CYCLE TPN. By the way, try to reassess estimated caloric needs via

indirect calorimetry. Avoid more insulin administration as it may contribute to fatty liver (steatosis) - Cx: Bacterial Translocation: We meet again! This is usually in pediatrics. Occurs due to gut atrophy. We can

slam these kids with Flagyl 250mg po/iv q8 and feed them po glutamine - Cx: Cholestasis: Another case of gut atrophy in patients accompanied by decrease bile release.

Glucose Intolerance: Overfeeding is the most likely cause of glucose intolerance in the non-diabetic patient - Sx: Hyperglycemia - Solution: Reassess caloric needs using indirect calorimetry, adjust components as necessary. Insulin is the last

resort option, because it could promote steatosis (fatty liver) Refeeding Syndrome: Glucose is often the culprit! This syndrome occurs in patients with a decreased oral intake for extended periods of time, resulting in Hypokalemia, Hypophosphatemia, and Hypomagnesemia

- Goal: Anticipate patients at risk for refeeding syndrome to help prevent major complications! - There are major and minor risk factors. One major risk factor, or 2 minor risk factors is sufficient to suggest the

patient is at a high risk of refeeding syndrome. - *It was recommended to know these factors for the exam - Mechanism: As glucose feeding is initiated, the already

nutrient-depleted patient will incur further losses due to glucose metabolism. Worsening of

o Hypophosphatemia o Hypomagnesemia o Hypokalemia

- Feeding the at risk individual o Check baseline electrolytes before initiating nutrition

support and replace those with low levels o Initiate PN SLOWLY (1/2 glucose requirement) o Monitor electrolytes closely when PN is first initiated,

aggressively replace electrolytes as needed o **Anticipate lower requirements when body stores are

replete, no need to get toxic. o **Do not increase dextrose until the electrolyte levels are normal.