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Flashcards in Renal + Bariatric surgeries Deck (144)
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Name 5 indications for bariatric surgery

- BMI ≥ 40
- BMI > 35 with significant obesity-related comorbidities (e.g. MetS, OSA, Osteoarthritis, HTN, …)
- Acceptable operative risk (risk of surgery < risk of not undergoing surgery)
- Failure of non-surgical weight loss attempts
- Well-informed, compliant, and motivated patient (need to understand lifestyle habits still have to change despite the surgery being done)


Name 6 contraindications to bariatric surgery

Active substance abuse (drugs, alcohol)
Uncontrolled psychiatric illness
Pulmonary hypertension
Severe cardiac and respiratory disease
Active pregnancy


Name 4 disadvantages of gastric bands

- Requires frequent adjustments (cannot tighten too much at once; requires adjustments --> better for people who live close to the center)
- Unknown durability of the band (research does not support this procedure, poor long-term outcomes – no longer covered by insurance)
- Can lead to band erosion and damage the tissue of the stomach.
- Band can also leak which requires more surgeries to fix.


Where does the common limb start in a RYGB? In a BPD-DS?

RYGB: Common limb starts at proximal jejunum
Switch: ≈ 100 cm of the ileum


How do we calculate excess weight loss (EWL)?

% Excess weight loss (EWL) = (Pre-op BW – CBW)/(Pre-op BW – IBW) x 100
IBW is at BMI 25


Why is there a resolution of T2DM in bariatric surgeries?

Not d/t weight loss but rather to gut hormone changes


What is the pattern of weight loss after bariatric surgery?

o Rapid weight loss occurs over first 12 months post-op
o Most significant loss seen in the first 6 months post-op (fastest loss occurs over 6 months; and for the next 6 months about ½ of the weight lost in the first 6 months is lost) --> patients get discouraged
o Stabilizes after 12 months (goal is maintenance)


What are the 3 mechanisms of weight loss in bariatric surgeries?

1. Gastric restriction (all surgeries) --> reduced PO intake

2. Alimentary/Roux limb length (RYGB, BPD-DS)
- Longer roux limb means shorter common limb = more malabsorption and vice versa
- Shorter common channel length --> more malabsorption

3. Gut hormones (RYGB, sleeve, BPD-DS)
- Decreased Ghrelin (orexigenic hormone) secretion - Produced by the parietal cells (in the gastric fundus), which is removed
- Increased leptin (produced by adipocytes)
- PYY hormone involved in DM resolvement – not a lot of evidence


Name late complications of bariatric surgeries

Ulcer, stricture, obstruction, hernia, nutrition deficiencies, dumping syndrome, weight regain or weight loss failure, psychological complications, malnutrition, gastric reflux


Name early complications of bariatric surgeries

Bleeding, anastomotic leak, infection, strictures, obstructions


What are the nutrition guidelines post op for bariatric surgeries?

Texture progression (to prevent vomiting and promote healing)
 Clear fluids (1-3 days)
 Full fluids/puree (5 weeks) (applesauce, oatmeal, pureed meat…)
 Solids (for life)

Portion progression
After surgery, the stomach and SI are swollen and inflamed – can only eat a small amount
o ½ cup to start, increase to 1 cup portions per meal/snack


What is the effect of the removal of the stomach fundus on nutrient absorption?

Removal of fundus (fewer parietal cells)
 Reduced gastric acidity (hydrochloric acid helps in the digestion of protein, calcium and iron)
 Reduced intrinsic factor (IF)


What are the nutrients to watch for in RYGB? Switch?

Gastric bypass nutrients to watch for:
• Calcium
• Iron
• Vitamin D
• Folate
• Vitamin B12 (intrinsic factor in the stomach)

Duodenal switch nutrients to watch for:
• Calcium
• Iron
• ADEK (fat-soluble vitamins) – they are usually absorbed in the jejunum and beginning of ileum which are bypassed
• Folate
• Vitamin B12


Why is calcium citrate preferred over calcium carbonate after surgery?

It is preferred to use calcium citrate instead of calcium carbonate after a surgery because calcium carbonate requires an acidic component to be absorbed while calcium citrate contains an acidic component


Which deficiencies may appear later?

Zinc and copper deficiencies usually appear later (2-3 years) because they have adequate stores before


Differentiate primary protein malnutrition to secondary PM

Primary protein malnutrition (PM) or protein-energy malnutrition (PEM)
o Rare but at risk in all bariatric surgeries
o D/t decreased oral intake/volume restriction

Secondary PM or PEM
o RYGB (rare) and BPD-DS (uncommon, but possible)
o D/t malabsorption


When is there most LBM loss after surgery? What are the implications?

Most LBM loss occurs within 3 months post-op (PO intake is still poor; trying to advance on texture and volumes)
LBM loss may lead to reduced RMR and reduced muscle strength and physical function (and puts them at risk of regaining weight over time)

o Inevitable LBM loss, but try to minimize as much as possible


What are the protein recommendations in bariatric surgeries?

Band, sleeve, RYGB
o 1.0-1.5 g/kg IBW (≈ 60-120g/d); may use Adjusted BW d/t very high BMI

o 1.5-2.0 g/kg IBW (≈ 90-120g/d) d/t significant malabsorption  may use Adjusted BW d/t very high BMI
Based on expert opinion

Focus in high biological value/high quality protein
o High PDCAAS: egg white, whey, casein, soy
o Low PDCAAS: collagen, gelatin


Name common tolerance issues after surgery.

Dehydration – hard to drink enough after surgery

Constipation – reduced PO intake = reduced fiber intake (+ we focus more on protein)

o Lactose intolerance (less lactase enzyme if SI has been removed)
o Dumping syndrome
o Sugar alcohols
o Other?

Food intolerances
o Dysgeusia (things taste metallic)
o Regurgitation (max physical capacity of stomach)
o Esophageal dysphagia (hurts)


Name possible causes of vomiting post-sx

• Esophageal dysphagia?
• Poor chewing
• Overeating
• Eating too quickly
• Eating tough, fibrous foods, doughy breads, dry meat
• Stricture (If a patient vomits everything he/she eats (even pureed foods) but can tolerate water = probably a stricture)


With which surgery(ies) is dumping syndrome common?

Occurs with RYGB due to the removal of the pyloric sphincter. Occurs in 85% of patients with GB, 30% of those with sleeves. No pyloric sphincter: Undigested food touches SI too soon --> osmosis


Describe the 2 phases of dumping syndrome

“early” phase:
o Occurs 10-30 minutes PC
o D/t rapid transit of hyperosmotic food into the jejunum (usually simple sugars)
o Symptoms: dizziness, nausea, weakness, rapid pulse, diarrhea (similar to hypo)

“Late” phase:
o Occurs 1-3h PC
o Reactive hypoglycemia due to an exaggerated release of insulin d/t surge of glucose in the SI --> pancreas sends a surge of insulin --> end up with a surge in BG d/t simple sugars entering the blood and then a drop


What nutrition interventions are recommended for dumping syndrome?

o Healthy snacking
o Advise glucometer
o Avoidance of trigger foods (limiting simple sugars)
o Label reading (≤ 25 g absorbable carb)
* ≥ 25 g absorbable carb can lead to dumping syndrome


What is nesidioblastosis and what can be done to avoid?

Nesidioblastosis (hyperinsulinemic hypoglycemia) may happen when patients eat high carb low protein meal

Nutrition intervention
o Increase in protein:carb ratio at lunch and PM snack
o If no change in symptoms, see an endocrinologist (may be put on acarbose)


What are 3 possible causes of hair loss post surgery?

- weight loss (happens in about 50% of bariatric patients); Shock loss – premature loss of hair before growth of next “batch”
Thinning or shedding of hair d/t weight loss and physiological stress of surgery
Occurs between 3-6 months post-op (early hair loss) – can go on to 9 months

Late hair loss (about 2-3 years after surgery) conduct dietary assessment and bloodwork; calculate protein intake

-Protein deficiency (needs are higher)

- zinc deficiency (gummy MVI have less calcium, iron and zinc…)
Prevalence of zinc deficiency among patients with a switch: 70%
Symptoms of Zn deficiency: Hair loss, dysgeusia
Consider zinc deficiency if…
o Hair loss starts > 6-9 months post-op
o Attaining protein needs
o Insufficient zinc supplementation


What can be done to reverse Zn deficiency?

Nutrition intervention
o Zinc supplementation: 60 mg elemental BID
o Monitor plasma zinc in bloodwork
o Suggest complete MVI to patient considering…


Name 5 causes for weight regain post-op

• Dietary habits
Increased calories: sugar and fat; Grazing: emotional eating
Not delaying fluids (drinking and eating at the same time)
• Poorly controlled thyroid
• New medications (weight promoting, antidepressants)
• Stopped exercising
• Surgical reasons? (only in 10% of cases; unlikely…)


Define GFR

Expression of the quantity of glomerular filtrate formed each minute in the nephrons of both kidneys, calculated by measuring the clearance of specific substances (inulin or creatinine)


Name 6 factors that can influence urine creatinine

• Diet, muscle breakdown, lab calibration bias, extra-renal elimination (gut bacteria), age, Antibiotics…


Classify the 5 stakes of CKS based on their GFR.

Stage 1: Kidney damage with normal or increased GFR
Stage 2: GFR 60-89
Stage 3: GFR 30-59
Stage 4: GFR 15-29
Stage 5: GFR < 15 or dialysis