Clinical Nutrition

by Muying Li (Lena and Orson’s student)

Registered Dietitian (RD/RDN)

Board certified professionals. Meet the CDR’s criteria to earn the cred. Highly regulated with training requirements and clinical rotations. You are an expert in identifying and treating ddisease-related malnutirition and conducting medical nutrition therapy. Renew every 5 years. Takes minimum ~1,000 hours. You also need a masters degree. You need “CPEU”s — kinda like credits (for every paper, research, conference, poster you have). You need 75 every 5 years. Keeps ya fresh and up to date ya know?

Pass the CDR exam (You are now an RD) → Get Licensure/Certification (You can now practice!)

Guidelines matter only for healthy populations; if you have cancer or other diseases, these change.

warning

Nutritionist has no such requirement! You cannot work in a clinical setting. You can get this shit online. Vibes-based.

Can a Dietitian call themselves a Nutritionist? Can an Astronomer call themselves an Astrologer?

You can also become an Advanced RD. You need to be a Board Certified Specialist (e.g. in oncology). There’s also an Advanced Practitioner Certification in Clinical Nutrition (RD-APs).

You can work in Clinic, Research, Education, Government, private practice, Nutrition Supplement companies (lol).

Clinical Nutrition and Why it Matters

Nutrition affects every stage of care: healing (wounds, infections, ulcers), muscle mass, toleration of medical treatment… watch your food! Attitudes around nutrition have changed a lot.

If you are malnourished (i.e. any kind of nutrition imbalance that leads to weight loss, lean body mass loss, loss of fat stores, reduced function), longer stays, higher likelihoods of complicationsa and readmissions, higher costs, higher in-hospital mortalities.

There’s Starvation, Chronic/Disease, and Acute malnutirition (e.g. a gunshot).

People become more malnourished at a hospital! Think about it: you are enfeebled, mentally and physically and subject to nutrient loss, they aren’t handing out cookie dough, you have increased metabolic demand.

Clinical Nutrition is high-impact but not always very visible.

Clinical RD Role

• Tailor nutrition
• Transition of care: education

There are all sorts of Clinical RDs (in/out patient, adult/pediatrics, long-term care, unit (general, oncology, cardiac rehab, renal, etc)/float (a generalist)-based.)

In-Patient Workflow

Home -> Hospital -> (Discharge) ---------> Home (Follow-up Out-patient visits)
           |             |
           |    Nutrition Education
           |
Initial assessment, follow-ups

Dietitians and physicians ask different questions.

• Is the nutrition adequate?
• Increased needs for protein? Energy?
• What is the safest route? PO, EN, PPN, TPN
• How will we monitor reponse and complications?
• Any drug-food interactions
• etc etc etc

Artifacts and Models

Physicians use SOAP but RDs use ADIME — Assessment, Diagnosis, Interventions, Monitoring, Evaluation.

See also the Nutrition Care Process (NCP) Model.

Basically they look for drugs and conditions that are pertinent to nutrition.

E.g. Propofol: rapid, intravenous sedative-hypnotic. Provides 1.1 kCal/Ml. Now if you take 25 mL/Hr of it you get $25 \times 1.1 \times 24 = 660$ calories in the day! This is the kind of thing Dietitians think about!

Other things of interest might be Omeprazole (proton-pump inhibitor), MiraLAX (stool softener) or Senokot (stimulates muscle) — they watch for dehydration.

Nutrition Support

Lots of math here. There’s Enteral Nutrition (directly to the gut, AKA Tube Feeding) which is different than Parenteral Nutrition which is through an IV (Central Line).

warning

Note that you really want to have them eat first, tube next, and IV last. If the gut works, use it.

Enteral Nutrition — Short Term: go through nose (easiest), then go through duodenum, and jejunum (through a small hole.)

Enteral Nutrition — Long Term: G-tube (gastronomy tube) or J-tube (jejunostomy tube).

Formulas - provide energy, protein, fluids. Three kinds:

1. Polymeric (intact, Ensure, get at CVS)
2. Monomeric (pre-digested / hydrolyzed)
3. Disease-Specific (DM, CKD, etc)

Nutrition Focused Physical Exam

Edema, Abdomen, Skin, Body Fat Stores, Lean Body Mass Stores (protruding clavicle, there’s less of the Deltoid muscle).

See the ASPEN Criteria that is widely used:

Ideal Body Weight

• Females: 100# for first 5ft, 5# for each additional inch.
• Males: 106# first 5ft, 5# for each additional inch.

BMI is your weight in Kg divided by your height in meters squared. There’s also

Nutrient Needs

Energy

Patient Type	Estimated Energy Needs
Healthy Adult, Ambulatory	25–30 kcal/kg
Healthy Adult, Active	30–35 kcal/kg
Overweight	21–25 kcal/kg
Obese	18–21 kcal/kg
Critically ill, intubated	25–30 kcal/kg
Critically ill (BMI >30)	11–14 kcal/kg actual body weight

Patient Type	Estimated Energy Needs
Cancer	25–35 kcal/kg
Cancer, head & neck	28–32 kcal/kg; 30–40 kcal/kg if wt loss
CKD stages 1–4	25–30 kcal/kg
CKD Stage 5 on dialysis	30–35 kcal/kg
Cirrhosis	25–35 kcal/kg
Transplant, < 6 months post-op	30–35 kcal/kg
Transplant, >6 months post-op	25–30 kcal/kg

Protein

Condition	Protein Requirement
DRI Reference	0.8 g/kg body weight
Adult maintenance	0.8–1 g/kg
Older Adults	$\ge$ 1 g/kg
Renal disease (pre-dialysis, stage IV)	0.6–0.8 g/kg
Renal disease (hemodialysis)	$\ge$ 1.2–1.3 g/kg (up to 1.5–1.8 g/kg)
Hepatitis (acute or chronic)	1–1.5 g/kg
Hepatic encephalopathy	0.6–0.8 g/kg (BCAA if refractory)

Condition	Protein Requirement
Organ transplant (short term)	1.5–2 g/kg
Organ transplant (long term)	1 g/kg
Pregnancy	+25 g/day in 2nd & 3rd trimesters
Pulmonary disease	1.2–1.5 g/kg
Critical illness (burns, sepsis, TBI)	1.5–2 g/kg
Stroke	1–1.2 g/kg

Condition	Protein Requirement
Cancer	1–1.5 g/kg (1.5–2.5 if cachectic)
Bone Marrow Transplant	1.5 g/kg
Inflammatory bowel disease	1–1.5 g/kg
Short bowel syndrome	1.5–2 g/kg
BMI >27, normal renal/liver	1.5–2 g/kg IBW
Obesity Class I or II, trauma (ICU)	1.9 g/kg IBW
Obesity Class III, trauma (ICU)	2.5 g/kg IBW

Fluid

Goals

• Maintenance of adequate hydration
• Tissue perfusion
• Electrolyte balance

Needs based on

• Body weight
• Body surface
• RDA

Consider

• Insensible losses: 75% skin, 25% lung (500–900 ml)
• Measured losses: stool (250 ml), urine (800–1500 ml), other drainage
• Fluid balance alterations due to:
  • Metabolic changes (fever)
  • Disease states (CHF, CKD/dialysis)
  • Medical therapy (diuretic treatment)

Factors increasing fluid needs

• Fever: 13% for each 1°C above normal (37°C); ~7% per °F
• Sweating: 10–25%
• Hyperventilation: 10–60%
• Extraordinary wound/fistula, gastric and/or renal fluid losses: varies (based on average 24-hour output)

Based on Age

• Young Adult: 35–40 ml/kg (actual body weight)
• 20–55 years old: 30–35 ml/kg (may be higher if active)
• 55–75 years old: 25–30 ml/kg

• 75 years old: 25 ml/kg; >100 years old: 20 ml/kg

Methods

• RDA Method: 1 ml fluid per 1 kcal of estimated needs
• Fluid Balance Method: Total output + 500 mL/day

Holiday-Segar Method

• < 10 kg: 100 ml/kg
• 11–20 kg: 1000 ml + 50 ml/kg for each kg >10 kg

• 20 kg: 1500 ml + 20 ml/kg for each kg >20 kg

Fluid Requirement Equations

Method	Details
Weight-based (18–55 yr)	35 mL/kg
Weight-based (56–75 yr)	30 mL/kg
Weight-based (>75 yr)	25 mL/kg
Tiered method	100 mL/kg for 1st 10 kg + 50 mL/kg for 2nd 10 kg + 20 mL/kg (≤50 yr) or +15 mL/kg (>50 yr)
Instruction	Take average of the two methods
Additional fluids	Add for losses: loose stool, drains, fistulas, ostomy, G-tube output, large draining wounds, emesis, drooling, paracentesis, lactation

ASPEN Malnutrition Criteria

Severe Malnutrition

Criteria	Acute Illness	Chronic Illness	Social Circumstances
Weight loss	>2% in 1 wk; >5% in 1 mo; >7.5% in 3 mo	$\lt$ 5% in 1 mo; $\lt$ 7.5% in 3 mo; $\lt$ 10% in 6 mo; $\lt$ 20% in 12 mo	$\lt$ 5% in 1 mo; $\lt$ 7.5% in 3 mo; $\lt$ 10% in 6 mo; $\lt$ 20% in 12 mo
Energy intake	≤50% of needs for $\ge$ 5 d	≤75% of needs for $\ge$ 1 mo	≤50% of needs for $\ge$ 1 mo
Body fat / muscle	Moderate depletion	Severe depletion	Severe depletion
Fluid accumulation	Moderate to severe	Severe	Severe
Functional status	Measurably reduced	Measurably reduced	Measurably reduced

Moderate Malnutrition

Criteria	Acute Illness	Chronic Illness	Social Circumstances
Weight loss	1–2% in 1 wk; 5% in 1 mo; 7.5% in 3 mo	5% in 1 mo; 7.5% in 3 mo; 10% in 6 mo; 20% in 12 mo	5% in 1 mo; 7.5% in 3 mo; 10% in 6 mo; 20% in 12 mo
Energy intake	$\lt$ 75% of needs for $\gt$ 7 d	$\lt$ 75% of needs for $\ge$ 1 mo	$\lt$ 75% of needs for $\ge$ 3 mo
Body fat / muscle	Mild depletion	Mild depletion	Mild depletion
Fluid accumulation	Mild	Mild	Mild
Functional status	Not applicable	Not applicable	Not applicable

Other

• Nutritional diagnosis $\ne$ Medical diagnosis.
• PES Statement: Problem/Etiology (Root Cause)/Signs+Symptoms — “Inability to eat at this time related to unresponsiveness and mechanical ventilation as evidenced by indication for enteral nutrition support to meet estimated needs.”

Anthropometric Data (Adult)

• Height
• Weight
• BMI (kg/m^2)
• Ideal body weight (IBW)
• Percent ideal body weight
  • %IBW = Actual weight / IBW × 100
• Usual body weight (UBW)
  • %UBW = Actual weight / UBW × 100
• Percent weight change
  • (UBW - Actual Wt) / UBW × 100

IBW

• Females: 100# for first 5 ft + 5# for each additional inch
• Males: 106# for first 5 ft + 6# for each additional inch
• Assumes medium frame size; adjust +/-10% for frame size to estimate an appropriate desirable body weight range
• For height less than 5 ft, subtract 2# for each inch below 5 ft
• Adjusting for amputations

Clinical Nutrition Informatics

Can you name one Clinical Nutrition Informatics tool? Yep. It’s pretty underrepresented.

Why? For one, IV nutrition might be ‘easy’ to capture but oral nutrition is much harder (did they eat things? Did their family bring them food?). Nutrition also changes over time and in context. Information is spread across notes, flowsheets, labs, orders, report. Variables are behavioural, function, social; not just biomedical.

Challenges & Opportunities!

• Poor integration of intake, symptoms, labs, and feeding data
• Weak decision support for consult timing, route selection, and follow-up
• Nutrition problems are often recognized late rather than early
• Earlier identification of nutrition risk
• Better integration of nutrition-relevant data
• Smarter consults and decision support
• Longitudinal monitoring across inpatient and outpatient care
• More personalized and adaptive nutrition interventions
• Better visibility of nutrition within the care team