Therapeutics Exam 3 (Parenteral and Enteral Nutrition) Flashcards
What is the equation for ideal body weight?
Male= 50 kg + (2.3 x inches over 60’’)
Female= 45.5 kg + (2.3 x inches over 60”)
What is the equation for Nutrition Body Weight (NBW)?
NBW= IBW + 0.25(wt - IBW)
When do you use NBW?
If actual body weight is 130% or more of IBW
When conducting a nutritional assessment, what do we take into consideration?
-Risk factors for malnutrition
-History
-Anthropometrics
-Classifications of malnutrition
-Nitrogen balance
UBW (Under Body Weight) is considered what?
20% below IBW
***What are the risk factors for malnutrition?
UBW (under body weight) =20% below IBW
Involuntary weight loss >10% in 6 months
NPO > 10 days*
(clinically use > 7 days)
Gut malfunction*
Mechanical Ventilation*
Increased Metabolic Needs (trauma/burn, high dose steroids)
Alcohol/substance abuse (empty calories)
Protracted nutrient losses (chronic disease)
.
.
.
** refers to ICU patients
When a patient is expected to be NPO, what amount of days of NPO would we want to start nutrition?
Start nutrition if patient is expected to be NPO for >7 days
All hospitalized patients should receive nutrition within how long after hospitalization?
48 hours
What are the 2 main screening tools used for nutritional risk screening?
NUTRIC
Nutritional Risk Score (NRS-2002)
What NUTRIC score indicates that a patient is at high nutritional risk?
6-10
(5-9 without IL-6)
What NUTRIC score indicates that a patient is at low nutritional risk?
0-5
(0-4 without IL-6)
Which part of supplemental nutrition is the most important?
Protein, most patients do not get enough
When doing a nutritional assessment, what does anthropometrics refer to?
Somatic (muscle) protein status
*most patients do not receive enough protein
*look at trends
Why is albumin not used as a nutritional marker?
It has a long half-life and most patients are in the hospital for only a few days
What nutritional monitoring parameters do we use to assess visceral protein status?
Transthyretin (prealbumin)
**but never used alone
C-Reactive Protein (CRP)
***What is the normal serum concentration of prealbumin?
15-40 mg/dL
What does an increased CRP mean?
The body is in an inflammatory state
When CRP goes up, what does prealbumin do?
Goes down
What is a normal CRP?
< 1 mg/dL
If prealbumin decreases as CRP increases, what does this mean?
Inflammation
If prealbumin decreases as CRP is normal, what does this mean?
Malnutrition
What are the 3 classifications of malnutrition?
Marasmus
Kwashiorkor
Mixed
What is Marasmus?
Protein-Calorie malnutrition
(both protein and calories are low)
What is Kwashiorkor?
Protein malnutrition
(only protein is low)
Regarding nitrogen balance, what does high urea in the urine indicate and why?
High urea= High protein breakdown
When protein is broken down (catabolized) it is converted to nitrogen which gets converted to urea and excreted in the urine
What does UUN stand for?
Urinary Urea Nitrogen
Over how long do we measure Urinary Urea Nitrogen?
24-hour urine collection
Urinary Urea Nitrogen (UUN) represents what % of total nitrogen excretion?
85-90%
What is a nitrogen balance study used to assess?
The adequacy of protein repletion
What is the ideal goal nitrogen balance?
+3 to +5 grams
*want more protein going in than going out, do not want a balance of 0
What is the formula for nitrogen balance?
Nitrogen Balance= (N in) - (N out)
N in= (24-hr protein intake [g])/ 6.25
N out= 24-hour UUN (g) + 4 g
How do we give someone nitrogen if they are not receiving enough?
Cannot give someone nitrogen alone, have to give it in the form of amino acids/protein
When estimating caloric needs, what does the Harris-Benedict Equation give you?
Basal Energy Expenditure (BEE)
or
Resting Energy Expenditure (REE)
What is Basal Energy Expenditure (BEE)?
Bare minimum amount of energy/calories to maintain life
(if you are laying there doing nothing)
What is Resting Energy Expenditure (REE)?
Energy being spent by a person at rest
1 inch= how many cm?
2.54 cm
What is the equation for Total Energy Expenditure (TEE)?
TEE= REE x stress or activity factors
What is the recommended amount of calories per day for a Non-stressed, Non-depleted patient?
20-25 kcal/kg/day
What is the recommended amount of calories per day for a Stressed/Hospitalized patient?
25-30 kcal/kg/day
*note that this applies to trauma/stress/surgery patients, critically ill, and major burns
What is the most specific method to calculate caloric requirements?
Indirect Calorimetry
When would we use indirect calorimetry to estimate calorie requirements?
For critically ill patients
What two pieces of data does indirect calorimetry give you?
REE (resting energy expenditure)
RQ (respiratory quotient)
What is an RQ?
Respiratory quotient
(How much CO2 is produced vs how much oxygen is consumed)
*****What is the equation for TEE?
TEE= REE x 1.2
What is the goal range for the RQ?
0.85-0.95
(Above this is overfeeding)
(Below this is underfeeding)
How often do we monitor RQ?
Once weekly
What is the recommended amount of protein per day for a mild to moderate stress patient (floor patients)?
1-1.5 gm/kg/day
What is the recommended amount of protein per day for a moderate to severe stress patient (ICU, trauma, surgery, burn)?
1.5-2 gm/kg/day
How do calories affect protein utilization?
Adequate calories must be present for appropriate protein utilization
*ensure patient is receiving enough non-protein calories
True or False: We usually include protein in calculation of total calories
True
*we subtract protein for Non-Protein Calories (NPC)
What is the standard distribution of dextrose to fat in non-protein calorie distribution?
70% dextrose
30% fat
(70/30)
During sepsis or bloodstream infections, what is the standard calorie distribution of dextrose and fat?
100% dextrose
0% fat
-Used in blood stream infections/fungal infections
(putting fat in the blood stream would feed the infection)
What is parenteral nutrition (PN)?
The process of supplying nutrients via an IV delivery system
What are the synonyms for parenteral nutrition (PN)?
TPN
PN
TNA (total nutrient admixture)
3-in-1
**What are the indications for parenteral nutrition?
Anticipated prolonged NPO course >7 days
Inability to absorb nutrients via the gut
-Ileus
-Small bowel resection
-Malabsorptive states
-Intractable vomiting/diarrhea
Enterocutaneous fistulas
Inflammatory Bowel Disease
Hyperemesis Gravidum
Bone Marrow Transplantation (mucositis)
What total osmolarity should you restrict peripheral PN to?
< 900 mOsm/L
(because if it is super concentrated then it will not be accepted by the body)
What are some limitations to using peripheral PN?
-Requires large volumes of liquid (may not be good for HF or AKI/CKD patients)
-Limited in calories
-Short-Term Access (<7-10 days) *put a central line in ASAP
**Many hospitals do not do the peripheral route
What are the advantages of central PN?
-Allows for administration of hypertonic solutions
-More calories can be delivered
What are the disadvantages of central PN?
Infection risk
Not a benign procedure (risky)
What are the insertion sites for a central venous catheter?
Subclavian (SC) [Chest]
Internal Jugular (IJ) [Neck]
Femoral [Groin]
What are the long-term central venous access options?
PICC (peripherally inserted central catheter)
Tunneled
Implanted Port
What are the 3 main components of nutrition?
Protein
Carbohydrates (Dextrose)
Fat
**One gram protein= how many kcal?
One gram protein = 4 kcal
What is the maximum concentration of dextrose available?
D70% (D70W)
*we dilute this, do not put it directly into a vein
One gram of dextrose= how many kcal?
3.4 kcal
What is the maximum carbohydrate rate that can be utilized?
4-5 mg/kg/min
*do not exceed this rate because the liver can only process so many carbs
1 gram of lipids = how many kcal?
10 kcal
What are the 2 IV fat lipid emulsions used to prevent essential fatty acid deficiency?
Intralipid
SMOFlipid
Intralipid contains what?
Soybean oil
Water for injection
Egg yolk phospholipid*
Glycerin*
SMOFlipid contains what?
Soybean oil
Medium-chain triglycerides
Olive oil
Fish oil*
Which IV fat emulsion is more commonly used and why?
SMOFlipid
-improved liver function
-less increase in triglycerides from baseline
What is the maximum amount of lipids a patient can receive per day?
60% of caloric intake
Max of 2.5 g/kg/day *
Which drug can contribute to a patient’s lipids they are receiving?
Propofol
(sedative)
**need to subtract the dose from this drug from the total amount of lipids the patient needs
How many lipids does propofol provide?
1.1 kcal/mL
Which media is a good growth environment for bacteria?
Lipids/Fat
What are the limitations on how long a lipid bag can hang for?
IV fat emulsion by itself: 12 hours
Added as a TNA (3-in-1): 24 hours
What is a Total Nutrient Admixture?
“Custom TPN”
3-in-1
Dextrose, Amino Acids, and Lipids in one bag
What is a Conventional Administration TPN?
“Custom TPN”
Dextrose and Amino Acids in one bag
Lipids 2-3 times per week separately
What is a Premix Solution For Injection?
“Standard TPN”
Available with or without electrolytes
*NO LIPIDS (not stable enough)
Who would we administer Clinimix E to?
CrCl > or = 50
**do not give electrolytes to patients with CrCl < 50
How do we initiate PN titration?
Start at 25% of goal
Increase rate to final goal rate within 24 hrs
**only titrate the first bag, not every day
When initiating or discontinuing PN what lab value must we check?
Blood glucose
How often do we check blood glucose levels when initiating or discontinuing PN?
q 4-6 hours
Before each increase in rate
If BG > 200, continue at same rate for 4 hours and recheck
When would we consider starting insulin in a patient receiving PN?
If we check their BG and it is >200, then recheck it 4 hours later and it is still >200
How do we titrate a patient off of PN?
Decrease rate by half every 2 hours until rate is < 50 mL/min, then discontinue
When doing Cycling PN (infusion over 12-18hrs per day) what is the maximum rate that can be used?
No specific guidelines
Max= 200 mL/hr
What are the additives that can be put in PN?
Electrolytes
Vitamins
Trace Elements
Medications?
Which electrolytes should be used with caution in patients with renal disease?
Potassium
Phosphate
Magnesium
Which two electrolytes maintain acid-base balance?
Acetate
Chloride
Which two electrolytes can precipitate together?
Phosphorus
Calcium
To avoid Ca + Phos precipitation, what dose should be avoided?
> 150
When would you consider giving a patient zinc?
If they have large wounds
In which condition do we not want to give trace elements?
Livery dysfunction
Which two trace elements do we supplement individually with liver dysfunction?
Zinc
Selenium
True or False: The addition of iron to PN is not recommended
TRUE
-destabilizes fat emulsion
-may contribute to infectious complications
Which medication used for GERD or stress ulcer prophylaxis can go into PN?
Famotidine
Which medications are not compatible with PN?
PPIs
(“zoles”)
For patients requiring insulin, what type of insulin should be used?
Regular insulin only
What is the range of fluids a person should receive?
30-40 mL/kg/day
What units is phosphorus typically ordered in?
mMol
**need to convert to mEq
How do we convert mMol of phos to mEq?
1mMol phos = 1.4 mEq phos
What electrolyte functions as the acid in PN?
Chloride
What fraction of acid to base should be in PN?
2/3 Acid (chloride)
1/3 Base (acetate)
Why do we use acetate as a base?
You cannot put bicarb in a TPN because it would convert to chalk with calcium
We use acetate because it is converted to bicarb in the body
Which electrolytes are considered “positive” and need to be balanced?
Sodium
Potassium
Which electrolytes are considered “negative” and need to be balanced?
Phos
*Also Chloride and Acetate but these are done at the end
What is bacterial translocation and how is it caused?
Time-dependent passage of bacteria or endotoxins from the GI tract to extra-intestinal sites
When you stop feeding the gut, you stop making normal acid in the stomach
-This allows bacteria to grow
-They may then travel from below the diaphragm to above it
**You are less likely to see this complication if you are feeding the gut
**These bacteria can cause systemic infection
What are the baseline monitoring parameters we want to have before starting PN?
-Complete metabolic panel (including Ca, Mg, and Phos)
-Hepatic function panel
-Prealbumin/CRP
-PT/INR (bleeding risk)
-Glucose finger sticks q4-6 hrs
How often do we check a prealbumin/CRP?
Twice weekly
(half-life is 2-3 days)
How often do we check Triglyceride and Respiratory Quotient (RQ)/Indirect Calorimetry levels?
Weekly
What is refeeding syndrome?
Fluid, micronutrient, electrolyte, and vitamin imbalances
-Occurs within first few days of feeding a starved patient
*Could be life-threatening
***What are the 3 common electrolyte issues with refeeding syndrome?
Hypophosphatemia (first) [<2.4]
Hypomagnesemia [<1.7]
Hypokalemia [<3.5]
How do we prevent refeeding syndrome when starting nutrition?
-Replete electrolytes before initiating feeds
-Calculate everything like normal for a patient and then cut the nutrition in half
Limit:
Carbs (dextrose) to 100-150g
Fluids to 800 mL/day
-Increase calories/dextrose by 20-33% of goal every 1-2 days
-Give thiamine 100mg daily for 5-7 days
What percent of daily calories should be made of essential fatty acids?
4-10% of daily calories
What causes Essential Fatty Acid Deficiency (EFAD)?
Several weeks on a fat-free PN regimen
(10-14 days)
How many days do you have before you need to add fat to a TPN?
10 days
How do we prevent Essential Fatty Acid Deficiency (EFAD)?
-Provide 4% of caloric intake as lipids
Provide at least 500mL of 10% fat emulsion over 3-5 hours TWICE WEEKLY
or
Provide at least 250mL of 20% fat emulsion over 5-9 hours TWICE WEEKLY
When is enteral nutrition indicated?
Oral consumption is inadequate
Oral consumption is contraindicated (but not EN):
-Esophageal obstruction
-Head and neck surgery
-Dysphagia
-Trauma
-Cerebrovascular accident
-Dementia
What are the contraindications to enteral nutrition (EN)?
-Mechanical obstruction (hernia, tumors, adhesions, scar tissue)
-Non-mechanical obstruction (ileus-gut not moving)
-Intractable vomiting
-Severe malabsorption
-Severe GI hemorrhage
-Fistulas
What are the routes of administration for EN?
Nasogastric (NG)
Nasojejunal (NJ)
Orogastric (OG)
Orojejunal (OJ)
N= start in nose
O= start in mouth
G= end in stomach
J= end in small bowel (jejunum)
Gastrostomy (PEG) -long-term
Jejunostomy (PEG/PEJ)
Which tube is longer, thinner, and more bendy? Jejunal or Gastric
Jejunal
What is an advantage of using a gastric tube?
Meds can get put down the tube
*This tube is wider and has less risk of clogging
What patient factors make a jejunal tube a better choice to use?
High risk of aspirating
Vomiting
Gastric residuals
*if tube is in the stomach it will get vomited out, best to go straight to jejunum
What tubes can be used for long term access?
PEG or PEJ
What are the 4 methods of administration for EN?
Bolus
Intermittent
Continuous Infusion
Trickle or Trophic
When administering bolus EN< what rate do we use?
> 200mL formula over 5-10 minutes
What is the maximum volume of bolus EN that can be administered?
300-400mL
Bolus EN is primarily used for which patients?
Those with a feeding tube
What method of administration of EN is preferred for jejunal feedings?
Continuous Infusion
When initiating a tube feed, what is sometimes done to make sure that the patient is digesting properly?
Check for residuals every 4-6 hours
(stop feed of period of time, withdraw contents of tube and see if any feed is left in the stomach)
Having residuals of what volume may prompt us to stop EN?
> 500mL
(this mean that 5 hours of tube feed is sitting in the stomach)
What percent of goal calories are we trying to achieve with EN in the first week?
> 50-60% of goal calories
*if we cannot reach this, consider PN
True or False: Bowel sounds/flatus is required to start EN
FALSE
-EN will promote gut motility
Why do we not want to initiate EN in hemodynamically unstable patients?
Concern for intestinal ischemia
What is the main EN formula used in the ICU?
Impact 1.5
-has immune support
-use in: major elective surgery, trauma, burn, head/neck cancer, and mechanical ventilation
What is the standard EN formula?
Jevity
When should the EN formula Impact 1.5 be used with caution?
Sepsis
What are the components of EN?
Protein (either intact or partially digested/elemental)
Fat (either long-chain or medium-chain* fatty acids)
Carbohydrates
Which patients may be better off receiving elemental protein?
Patients with malabsorption or diarrhea
What is Pro-Stat?
A modular supplement of protein used in EN
Provides:
-15 g protein
-72 kcal
-3 g CHO
When should we give patients glutamine?
Reduces mortality in burn patients
**Do not supplement if patient is already receiving glutamine via an immune-modulating formula (Impact 1.5) *burn patients are an exception
When should we give patients probiotics?
Mixed data
Normally considered in diarrhea but new data shows it could cause diarrhea
*Just don’t give these
What are the possible GI complications of EN?
-High gastric residuals
-Aspiration
-Nausea/Vomiting
-Abdominal distention
-Diarrhea and Constipation **check meds
What are ways we can reduce the risk of aspiration?
*Elevate head of bed to 30-45 degrees
Administer as continuous infusion
Change to post-pyloric delivery
Prokinetic drugs or narcotic antagonists
What are the 4 prokinetic agents that can increase gut motility?
Metoclopramide
Erythromycin (QTc prolongation)
Naloxone (when opioids are causing constipation, can block receptors in the gut)
Methylnaltrexone (one time dose, last line)
If a patient develops diarrhea while on EN, what do we do?
Change to fiber-containing formula
Suspect Clostridium difficile (especially if antibiotic use)
Evaluate medications
Which medications may make a patient more likely to experience diarrhea?
Hyperosmolar meds
Liquid formulations with sorbitol*
Bowel regimen (but do not completely stop this)
Broad spectrum antibiotics
What are some common metabolic side effects of EN?
Hyper/Hypo glycemia
Overhydration/Dehydration
Electrolyte Imbalance (**hyponatremia)
What is the goal blood sugar level in the ICU?
< or = 180 mg/dL
What are the mechanical complications of EN?
Clogging of feeding tube
Tube malposition (assess with abdominal x-ray “KUB”)
Rhinitis + Sinusitis (from bacteria growing on nasal tube, need to reposition daily, can use a thinner tube or change to OG)
What are the possible medication-related complications associated with EN?
Clogged feeding tube
Drug-tube interaction
**What are the guidelines for medication delivery via enteral feeding tubes?
Liquid meds are preferred
Crush tablets to a fine powder or empty capsule contents, and mix with water
Do not crush SR or enteric coated medications
*Administer each med separately
*Adequately flush with water between each med and at end
Dilute hypertonic/irritating meds in 30 mL of water before administration
How much water should be used to flush a feeding tube before/after medication administration?
15-30 mL sterile water
Use 5-10mL between each med
What medications interact with tube feeds?
Antibiotics (Fluoroquinolones, Itraconazole, Tetracyclines, Penicillin)
Anti-Retrovirals (Didanosine, Dolutegravir, Indinavir)
Other: Levothyroxine, Warfarin, Phenytoin, Theophylline
If a patient is receiving a medication that interacts with their tube feed, how do we adjust the tube feed?
Hold, Wait 1 hr, Give med, Wait 2 hours, Resume tube feed
(off tube feed for a total of 3 hours per medication administration)
How often should we monitor serum electrolytes, glucose, BUN/SCr [CMP]?
Daily until stable
Then twice weekly
Then weekly
What considerations do we need to make for acute renal failure patients?
*Have increased protein requirements to prevent nitrogen deficiency
Continuous Renal Replacement Therapy: Max: 2.5 g/kg/day
Hemodialysis: 0.8-1.2 g/kg/day
*Prealbumin is eliminated renally and therefore is falsely high
What considerations do we need to make for pulmonary failure patients?
Fluid-restriction (need calorically dense formula)
Monitor phosphate closely
True or False: we cannot orally feed patients with acute pancreatitis
False, oral intake normally recovers in 3-7 days, not requiring PN
True or False: Parenteral nutrition does not affect pancreatic secretion and function
True
