Nutritional Support

Question 1

State the weight based range of daily energy requirement for general hospitalised patients

Answer 1

25-35 kcal/kg

Question 2

State the protein requirements for healthy adults

Answer 2

0.8g/kg/day

Question 3

State the protein requirements for trauma/ surgery/ burn patients

Answer 3

1.5-2g/kg/day

Question 4

State the protein requirements for sepsis or critical illness patients

Answer 4

1.5-2.5g/kg/day

Question 5

State the protein requirements for CKD patients not on dialysis

Answer 5

0.6-0.8g/kg/day

Question 6

State the protein requirements for CKD patients on dialysis (HD, PD, CRRT)

Answer 6

HD/PD: 1.2g/kg/day

CRRT: 2g/kg/day

Question 7

State the indication for Enteral Nutrition and some examples of patient groups where it may be indicated (4 group)

Answer 7

For patients who are unable to receive/tolerate adequate nutrition by the oral route

Examples:
o Swallowing impairment (e.g post stroke)
o Mechanical ventilation
o Altered mental status (e.g brain injury, loss of consciousness)
o Motility disorders
- E.g gastroparesis (common in T2DM; things dont flow down so have to insert tube to bypass non-functional section and deliver to distal gut)

Question 8

State the indication for Parenteral Nutrition and some examples of patient groups where it may be indicated (4 group)

Answer 8

For patients who are unable to receive or tolerate adequate nutrition by the enteral route

Examples:
* Paralytic ileus
o After trauma/surgery, intestine take some time to recover function
* Small bowel obstruction (e.g cancer obstructs lumen)
* High output / proximal fistula
* Mesenteric ischemia
o Blood flow to intestine not sufficient -> not enough energy to digest food -> may cause GI necrosis if overwork

Question 9

List the Pre-pyloric enteral access devices

List the pros (4) and cons (1) of these devices

Answer 9

Nasogastric Tube, Percutaneous endoscopic gastrostomy (PEG)

o Pros:
1) More physiologic (bypass less of the GI tract -> maximises the function of the GIT)
2) Higher tolerance to bolus feeding (large meal)
* Due to use of stomach as reservoir
3) Higher tolerance to a wide range of enteral products (especially those with higher osmolarity)
* Generally most physiologic osmolarity is 300 mOsm
4) May be used for venting
* Venting = removal of gastric fluid -> important in cases of obstruction as fluid buildup might cause aspiration pneumonia

o Cons:
1) Not to be used for feeding in patients with delayed gastric emptying -> use post-pyloric

Question 10

List the Post-pyloric enteral access devices

List the pros (3) and cons (1) of these devices

Answer 10

Nasojejunal tube, Percutaneous endoscopic Jejunostomy (PEJ)

o Pros:
1) Smaller bore, less discomfort
* Has to go through pyloric sphincter so less discomfort when inserting through the nose
2) May be used in conditions that result in dysfunctionality in proximal GIT
3) Minimize aspiration risk when feeding since bypasses stomach
o Cons:
1) Higher risk of tube clogging -> due to thinner tube

Question 11

Compare and contrast nasal and stomy tubes

Answer 11

o Nasal tubes can be inserted at bedside
o Less aesthetically pleasing
o Not as comfortable ?

• Stomy -> goes through abdomen and directly connected to intestine
  o Usually requires surgery to insert
  o More difficult to remove also and chance of wound not healing after it is removed -> but preferred if enteral nutrition needed lifelong

Question 12

List the potential complications of Enteral feeding (7) and risk factors where applicable.

List strategies to maximise tolerance to Enteral feeding (5)

Answer 12

Complications
1) Occlusion of feeding tube
* Jejunal > gastric tube (Recall: due to thinner tube)
* Medication administration
* Formula – more concentrated/high protein/fibre-enriched -> tend to adhere to tube more and cause blockage
2) Tube migration
* If cough too much, tube can migrate back up to stomach (for jejunal tube)
3) Infections secondary to microbial contamination
* A result of people just pouring water and diluting feeds rather than increasing flushing to meet water intake requirements
* To prevent this, don’t dilute nutritional feeds as water may promote bacterial growth and nutritional feeds usually left there for around 4 hours sometimes
4) Aspiration
5) Nausea/vomiting
6) Diarrhea/Constipation
7) Refeeding syndrome

Strategies
1) Continuous instead of bolus
2) Use of prokinetic agents (e.g. metoclopramide, domperidone, IV erythromycin) -> if complain of vomiting
* Note only IV form of Erythromycin is used as prokinetic, not PO
3) Post-pyloric feeding if intolerant to gastric feeding (if gastroparesis is the issue)
4) Use of isotonic formula (e.g. boost isocal)
5) Semi-elemental/elemental feeds for patients with malabsorptive issue (e.g. short bowel syndrome) -> but may still cause diarrhea

Question 13

Compare and contrast Central and Peripheral parenteral access devices (3)

Answer 13

Peripheral (anything through the peripheral veins)
o Tip position is located outside of central vessels
o Requires frequent re-site (change site around every 72 hours) as blood vessels are small
o Nutrient delivery limited by osmolarity and concentration (NUH cutoff: 900 mOsm) -> Too high osmolarity will burn the veins

Central
o Position of catheter tip is in large bore blood vessel e.g. distal superior vena cava, inferior vena cava, right atrium
- Areas with high blood flow -> doesn’t matter as much if nutrition is given in high osmolarity
o Can be used for longer term care (no need to re-site so frequently)
o Can give more nutrients in smaller volume

Question 14

List the component of Parenteral Nutrition that can be adjusted

Answer 14

Micronutrient component (electrolyte and vitamins)

Question 15

State the potential complications of Parenteral nutrition (Device related 3, Metabolic 5)

Answer 15

1) Device related complications
a) Occlusion in IV catheter
o Thrombosis / clotting (4 different types of thrombosis) -> can use heparin lock -> administer into catheter and let it dwell
o Inappropriate flushing techniques
- Recommended flush technique: push, pause -> cause turbulence that clear debris that is stuck onto walls of catheter
o Precipitates as a result of drug incompatibilities, crystallization
o Lipid residues increase risk of infections; change infusion set every 24 hours
b) Mal-positioning -> patient may pull out
c) Catheter-related bloodstream infection (CRBSI) -> use aseptic technique to minimise risk
2) Metabolic complications
* Refeeding syndrome
* Hyper/hypoglycemia -> due to direct administration into bloodstream; monitor
* Fluid overload -> due to direct administration into bloodstream
* Intestinal failure associated liver disease (IFALD)
* Metabolic bone disease (Osteomalacia, Osteoporosis)

Question 16

Pathophysiology of Refeeding Syndrome

Answer 16

1) Starvation and malnutrition cause increased glycogenolysis, gluconeogenesis and protein catabolism
* Serum electrolytes may appear normal initially as body draws from intracellular stores (result in overall depletion) and reduces renal excretion

2) Over time, this leads to protein, fat, mineral, electrolyte and vitamin depletion -> worsened by conditions such as diarrhea, loss of intestinal contents (eg, fistula, vomiting, gastric drainage), or diuretic use, which cause additional losses.

3) When refeeding starts, switch back to anabolism and fluid, salt, nutrients (CHO major energy source) enter body
* Can occur with any form of calorie provision – oral, EN, PN, IV dextrose

4) This leads to increased insulin secretion -> increase protein and glycogen synthesis. This leads to increased glucose uptake, utilization of thiamine and uptake of phosphate (to synthesis ATP), potassium and magnesium by cells.
* Thiamine is cofactor for energy metabolism

5) This disrupts electrochemical membrane potential leading to symptoms.
* POTENTIALLY FATAL - arrhythmia, cardiac failure, neuromuscular complications

Question 17

List criteria for patients at risk of Refeeding Syndrome

Answer 17

Patient has 1 feature:
- BMI < 16kg/m2
- Unintentional weight loss > 15% in past 3-6 months
- Little/ no intake for > 10 day
- Low K, Mg, P prior to restarting feeding

OR

2 or more of following features:
- BMI < 18.5kg/m2
- Unintentional weight loss > 10% in past 3-6 months
- Little/ no intake for > 5 day
- History of alcohol abuse or drug abuse including (insulin, chemotherapy, antacids or diuretics)

Question 18

State the management strategy for refeeding syndrome

Answer 18

1) Identify at risk patients
2) Check serum electrolytes at baseline
3) Correct deficiencies prior to feeding, defer feeding if electrolytes are critically low
4) Administer thiamine (Vit B1) supplement -> given as pre-emptive measure
5) Initiate feeding slowly and gradually increase over next few days to meet nutritional requirements (Start low and go slow!) -> Start at 40-50% of energy requirements
6) Continue to monitor electrolytes as feeding progresses, adjust amount of replacements as needed

Question 19

___ mmol KCl = ___ mmol/L increase in serum K

Answer 19

10 mmol KCl = 0.1 mmol/L increase in serum K

Question 20

List complications of malnutrition (6)

Answer 20

1) Increased complications e.g surgery patient need nutrition to recover
2) Poor wound healing -> require more surgeries and increased length of stay
3) Compromised immune status
4) Impairment of organ functions
* E.g insufficient energy supplied to neuronal cells -> affect cognition
* Heart needs energy to pump
5) Increased mortality (malnutrition increases risk of patient succumbing to their underlying condition -> indirect cause of death) e.g poor wound healing in GIT lead to leakage of intestinal contents into the abdominal space and cause sepsis
6) Increased use of healthcare resources

Question 21

List the 2 broad causes of malnutrition and examples of each cause

Answer 21

1) Decreased intake absorption (e.g Chemotherapy, Ascites, Intestinal Resection)
* Chemo cause nausea, vomiting, taste alteration -> decrease appetite for prolonged period
* For those with advanced abdominal cancers, they have ascites -> cause early satiety

2) Increased expenditure losses
* Stresses like burns, surgery, trauma, sepsis that increase body energy consumption
* Conditions that burn nutrients e.g dialysis

Question 22

List some of the methods used to calculate energy requirement (3)

Answer 22

Indirect calorimetry, Weight based, Predictive equations (Schofield, Harris-Benedict)

Question 23

List the 4 types of enteral feeds and describe them

Answer 23

1) Modular
- Contains single nutrient
- Used as fortifier to enhance a specific nutritional component/ augment oral diet (NOT meant to be meal replacement)

2) (Semi) Elemental
- Contains partially/ completely hydrolyzed nutrients
- For patients with impaired GI function, impaired tolerance to standard feeds -> patient has reduced absorption so want to help to break down nutrients first and rely less on GI function
- May still be quite high in osmolarity and hence cause diarrhea

3) Polymeric
- Contains intact macronutrients
- Requires sufficiently functional GIT

4) Disease specific/ Immune modulating
* Contains additions / restrictions of specific nutrients to meet needs for disease management
* May or may not meet individual’s full nutritional needs

Question 24

List the prevention and mitigation of drug nutrient interaction for enteral vs parenteral feed

Answer 24

Parenteral:
* Administer via separate peripheral IV cannula -> but problem for those with poor venous access
* If needed, pause PN administration, flush access device before and after drug administration before resuming PN infusion
o May need to check on BG to prevent hypoglycemia especially if drug to be administered over extended period of time

Enteral:
* Stop feeding, flush access device before and after drug administration -> prevents accumulation in tube
* Use therapeutic alternatives available in appropriate dosage form -> e.g drugs suitable for crushing