Week 3 Refeeding Syndrome Flashcards

1
Q

Define Refeeding Syndrome

A

Refeeding syndrome is a syndrome consisting of metabolic disturbances that occur as a result of reinstitution of nutrition to patients who are starved, severely malnourished (with/without cachexia) or metabolically stressed due to severe illness.

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2
Q

Risk factors for RFS in clinical practice

A
  • Patients who have gone for prolonged periods of little to no nutritional support where they have lost significant amounts of weight (may or may not be underweight)
  • And/or patients who have a syndrome associated with elevated resting energy expenditure (e.g cancer cachexia, burns) who may or may not have lost weight.
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3
Q

Examples of clinical populations who may experience refeeding syndrome

A
  • short gut
  • eating disorders
  • some cancers (e.g lung)
  • and/or conditions of hypermetabolism (e.g burns, short gut, end-stage liver failure). Usually this would could with weight loss but this is not the sole criteria.
  • It could also be when patients have had very low amounts of oral and/or nutritional support for pro-longer periods.
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4
Q

pathophysiology of refeeding syndrome

A
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5
Q

What can refeeding syndrome lead to?

A

This can lead to abnormalities in neurologic, cardiac, hematologic, neuromuscular and pulmonary function; people have died from this.

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6
Q

What are signs for risk of refeeding syndrome?

A
  • Hypophosphatemia
  • Hypokalemia
  • Hypomagnesemia
  • Vitamin/Thiamin Deficiency
  • Fluid and Sodium Retention
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7
Q

What happens when CHO introduced to someone who has not eat for a long time?

A

When introduce CHO → insulin is released → get uptake of phosphate, magnesium (Mg) and potassium (K+) into cells

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8
Q

What are phosphate and magnesium important for?

A

Both are important for ATP generation from glycolysis

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9
Q

What phosphate levels indicate risk for RFS?

A
  • Hypophosphatemia < 0.74 mmol/L indicates the patient is likely to get re-feeding syndrome in response to refeeding the patient.
  • Levels of phosphorus between 0.75-0.9 mmol/L and potassium values < 3.5 mmol/L in patients who fit the other criteria for refeeding risk, indicate that these patients are at very high risk for developing refeeding syndrome.
  • Normal phosphate is 1.1-1.8 mmol/L (up to 2 in children)
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10
Q

Clinical manifestations of hypophosphatemia

A

memory loss, bone pain, bruising, bleeding, lethargy, joint stiffness, arthritis, cyanosis, decreased cardiac output, respiratory failure, seizure, coma, death

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11
Q

Monitoring phosphorous levels

A

Monitor levels daily with refeeding and supplement with either oral or IV phosphate (depends on severity of hypophoshatemia)
* often when serum levels below 0.7 mmol/L; need IV source in doses ranging from 0.16-0.32 mmol/kg over 6 hours).

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12
Q

Clinical Manifestations of Hypokalemia

A

Nausea, vomiting, constipation, weakness, paralysis, respiratory compromise, muscle necrosis, myocardial contraction problems, cardiac arrythmias, bradycardia and atrial tacchycardia, ventricular fibrillation and sudden death

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13
Q

Serum levels of potassium

A
  • Normal serum levels: 3.5-5 mmol/L (slightly higher for children)
  • Hypokalemia < 3.5 mmol/L (in children < 3.6 mmol/L)
  • Important to monitor serum levels q daily if levels less than 3.0 mmol/L during re-feeding
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14
Q

Supplementing potassium

A
  • May need to supplement with oral potassium in the range of 0.5 mmol/kg/d (MD to prescribe)
  • Typically in forms of KCL, or K-citrate
  • May need to supplement IV route if serum levels < 2.5 mmol/L (note this is done by MD)
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15
Q

Problem with potassium supplementation

A

Potassium tends to be gastric irritant

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16
Q

Serum levels of magnesium

A
  • Normal Serum levels :0.8 -1.2 mmol/L
  • Hypomagnesium: serum levels < 0.8 mmol/L
17
Q

Supplementing Mg

A

Typically don’t supplement unless levels range below 0.5-0.6 mmol/L;(varies between centres)
* patients are typically asympotomatic until Mg levels fall below 0.4 mmol/L
* Typically supplement with magnesium oxide, glucoheptonate or hydroxide forms; causes diarrhea

18
Q

What is usually seen with hypomagnesium?

A

Usually see hypocalcemia and hypokalemia (which are very serious)

19
Q

Clincal manifestations of hypomagnesium

A

muscular weakness, vertigo, ataxia, leg cramps, nausea and vomiting, paresthesisa, hyperinsulinism and glucose intolerance, cardiac arrythmias etc.

20
Q

Clinical manifestations of thiamine deficiency

A
  • Wernike’s encephalopathy (thiamin), lactic acidosis, death
  • Wet Beri Beri (can lead to congestive heart failure) vs Dry Beri Beri (effects CNS and PNS)
21
Q

sodium and fluid with refeeding syndrome

A

Get expansion of extracellular water due to increased sodium and fluid intake.
* this often causes local edema/early weight gain (be careful what weight you use for the patient in calculations of energy/protein requirements)
* Can lead to pulmonary edema, cardiac decompensaton
*

22
Q

What to monitor with sodium and fluid retention

A
  • Fluid intake
  • Urine output >1-2 cc/kg/hr
  • Serum electrolytes: Na: 135-145 mmol/L (normal range).
  • Be careful of sudden increases in weight (>2 kg in one week).
  • May need to fluid restrict in early refeeding phases
23
Q

Preventing RFS with electrolyte supplementation

A

Measure serum electrolytes prior to initiation of feeds; start treatment for electrolyte abnormalities prior to starting nutrition support regimen.
* Most people recommend starting supplementation of phosphorus, potassium and magnesium empirically at start of feeds to minimize electrolyte fluctuations during refeeding.
* If patient on PN may add additional phosphorus, magnesium and potassium to PN solution (above routine concentrations)
* Phosphorus: may need 10-15 mmol of phosphate/1000 kcal to maintain normal serum levels
* Supplement with multivitamins (as high as 200-300 mg of thiamine, folate 1 mg/d)

24
Q

Risk assessment and management of RFS algorithm

A
25
Q

Starting tube feeds to prevent refeeding syndrome

A

Start feeds at less than BMR (70-80%) or less than 25% of estimated goal needs; typically this is 15-25 kcal/kg
* Fluid may need to be restricted < 1000 ml/24 hours and sodium of 20 mmol/d
* For children closer to 30 kcal/kg and for infants: 40-50 kcal/kg
* Increase nutrition support slowly over the course of 3- 5 days (expect to take up to 7 days to reach BMR.
* Monitor electrolytes as required.

26
Q

Treatment of refeeding syndrome

A
  • Start laboratory assessment of electrolytes
  • Stop nutrition support; start low IV of IV dextrose with electrolytes to prevent rebound hypoglycemia
  • IV supplementation of phosphorus, magnesium, and potassium
  • Supportive treatment: re: respiration and cardiac function
  • Consider renal function
  • Adjusted body weight to assess needs
  • Restart nutrition support at 50% of the previous rate, increase slowly over 4-7 days
27
Q

HOw can sodium and fluid retention be avoided?

A

Wt stability in first 8-10 days important to avoid fluid and sodium retention
* we avoided this by institution of strict TFI
* As increase protein intake, get increased diuresis; therefore possible to liberalize TFI

28
Q

What weight to use for patients at risk of RFS

A

Always use best estimate of dry weight in calculation of nutritional requirements in patients at risk for refeeding syndrome!

29
Q

Role of RD

A

ensure careful monitoring of fluid and electrolyte status, judicious increasing within the TFI of nutritional intervention.

30
Q

Starting protein, fat and dextrose for TPN

A
  • Protein: start at 0.5-1 g/kg; and slowly increase
  • Fat 0.5 g/kg fat and slowly increase
  • max dextrose is about 150 g dextrose for high risk patients; and for extreme risk of refeeding 50-100 g dextrose /d in the TPN solution.
31
Q

Preventing RFS for severely cachetic

A

If severely cachectic or shows signs of refeeding syndrome; start feeds slowly at 15-20 kcal/kg; and then increase slowly to goal of 30-40 kcal/kg. This could take several weeks to achieve.
* Protein: 1.2-1.5 g/kg
* If have cachexia; supplement with phosphorus, magnesium , potassium and multivitamins

32
Q

Rates for tube feeding

A

Keep rates at 0.2-0.3 cc/kg/hr over 24 hours. Which means over 8 hrs, the rates would be about 0.1 mls/kg/hr and then increase by a max of 0.1 mls/kg/hr
* consider that you might wish to increase feeds q 12 hrs. Very slow and carefully is the way to go…even if it means you only get up to 0.2 mls/kg/hr in the first 24 hrs.

33
Q

Overall recommendations for feeding strategies

A
34
Q

Electrolyte serum levels that require repletion

A