what doctors should know about nutritional support Flashcards
when oral nutrition is unsuccessful how do you provide nutrition?
- enteral (unless contraindicated - damaged/leaking/short/antonic/obstructed gut)
- parenteral
what does enteral mean?
using the gut
what does parenteral mean?
bypassing the gut
how is enteral nutrition provided?
nutritionally complete liquid feeds through various tubes which access the gut
when do you use enteral nutrition?
- if gut is functioning
- unable to swallow (eg - unconscious)
- insufficient oral intake despite supplements
- unable to tolerate supplements
- patient choice
how is parenteral nutrition provided?
nutritionally complete fluid feed which is broken down into glucose/amino acids/fats and engineers to be safely administered by IV
when do you use parenteral nutrition?
- if gut is not functioning
- aperistaltic
- obstructed
- too short (when less than 100 cm of small bowel)
- too damaged
- high fistula
- inaccessible
what are the advantages of nano-gadtric tube feeding?
- uses the gut (physiological)
- fast and easy to pass tube
- minimally invasive
- generally well tolerated
- easy to remove if not tolerated/no longer required
who is a nano-gastric tube suitable for?
- people with a working gut
- stomach emptying
- safe to put tube through nose and down oesophagus
- patient must accept/tolerate tube
- short term feeding
what are the risks of naso-gastric feeding?
- tube misplaced/displaced/blocked
- reflux/aspiration
- not tolerated (tube itself or volume of feed infused)
how is the feeding tube placement confirmed?
- chest x-ray view should be adequate (upper oesophagus down to below diaphragm)
- NG tube should remain in the midline down to the level of the diaphragm
- NG tube should biscuit the carina
- tip of NG tube should be clearly visible and below the diaphragm
- the tip of the NG tube should be 10cm beyond the GOJ to be confident it is within the stomach
what are the advantages of the naso-jejunal feeding?
- vomiting/gastropareisis/duodenal obstruction
- minimally invasive but need x-ray or endoscopy to place
- less likely to aspirate/get misplaced
what are the risks of nano-jejunal feeding?
- technically difficult
- generally needs endoscopy or placement in interventional radiology
- this can create a delay in feeding
- risk of mis/displacement
- may still not be tolerated
what is PEG and RIG?
- percutaneous endoscopic gastrostomy (PEG)
- radiologically inserted gastrostomy (RIG)
what are the advantages to PEG and RIG?
- uses the gut/physiological
- durable (tube lasts a couple of years, unlikely to be accidentally displaced)
- no tube in throat/on face
- comfort
- cosmetic
who is PEG and RIG suitable for?
- a functioning gut
- inability to swallow adequate food/fluid
- dure to an irréversible or long-lasting cause
- in whom nutrition support is thought to be appropriate
- who can tolerate an endoscopy and minor surgical procedure
what are the risks and shortcomings of PEG or RIG?
- perforation
- sepsis
- bleeding
- perforated viscous
- attached to a pump 20 hours per day
- misplacement
- reflux
- buried bumper
- death (6% at 30 days)
- not involved in mealtimes
- alteration in body image
what are the advantages of percutaneous jejunal access (surgical jejunostomy/PEJ/RIJ)?
- as for PEG plus
- tolerated if gastroparesis/duodenal obstruction
- longterm option for those requiring NJ feeding
what are the risks of PEJ?
- as for PEG but higher risk of complication due to position/anatomy of small bowel
- hence existence of PEG-J a PEG with an extension into the jejunum
what is total parenteral nutrition?
- fluid
- electrolytes
- protein (as amino acids)
- fat
- carbohydrate
- vitamins
- minerals
what are the problems with TPN?
- line ‘access’ complications (misplaces line, extravasation of TPN, clot on the line, line infection)
- hyperglycaemia
- fluid/electrolyte disturbance
- over or under-feeding
- liver disease
- gut not being used leading to atrophy and inflammation
- expensive
how do you monitor TPN?
- 4 hourly observations: temperature and blood glucose
- daily: U&E, Mg, Ca, Phosphate, LFT, FBC, line inspection, weight
- monthly: micronutrients, triglycerides
what is referring syndrome?
- severe electrolyte and fluid shifts associated with metabolic abnormalities in malnourished patients undergoing refeeeding wither orally, enterally or parenterally
what is the pathogenesis of re-feeding syndrome?
- during starvation energy is saved by switching off trans-membrane pumps
- Na (and water) drift intra-cellularly
- K and phosphate drift extra-cellularly (and are excreted to keep plasma levels stable) leading to total body depletion
what are the clinical signs of re-feeding syndrome?
as soon as you get an energy these are switched back on immediately:
- sudden drop in plasma K and phosphate leading to arrhythmia
- sudden surge in plasma Na and water leading to overload
how do you avoid/treat re-feeding?
- be aware of the risk
- check electrolytes
- begin replacement before feeding
- start slow and build up
- keep monitoring electrolytes daily and replacing as necessary
what is Wernicke-Korsakoff’s Syndrome (WKS)?
- a neurological disorder
- Wernicke’s encephalopathy and Kosakoff’s psychosis are the acute and chronic phases respectively of the same disease
what causes WKS?
deficiency in the B vitamin thiamine and is most frequently encountered in alcoholics
what are the key characteristics of Wenicke/Korsakoff?
- acute thiamine deficiency
- precipitated by providing calories in the absence of sufficient reserves of thiamine
- Wenicke’s: ophthalmoplegia, unsteady gait, nystagmus, confusion
- this is reversible but only if you act very quickly to give IV thiamine
- Korsakoff’s psychosis: sudden onset, dramatic, irreversible, memory loss, confabulation
how do you avoid/treat Wenicke’s?
- be aware of the risk
- replace thiamine before and during re-feeding
- if low risk and able to eat use high dose oral thiamine
- if high-risk of not eating then use IV Pabrinex
