feeding Flashcards
definition of parenteral feeding
IV administration of nutrients
may be supplemental to oral or tube eg in short bowel syndrome or Crohn’s - when nutrition cannot be sufficientlt absorbed in the gut
or be the only source - TPN
even if GI disease - enteral is safer, cheaper and at least as efficacious as parenteral nutrition in the perioperative period
indication for parenteral nutrition
considered for all patients who are malnourised or at risk of malnutrition
and have a non-functioning or inaccessable GIT preventing enteral feeding, and unlikely to work for 7days
peripheral line (peripherally inserted central catheters - PICCs, or standard cannulae) - short term support
central catheters and tunnelled subclavian vein central lines - >2wks
or dedicated lumen of multilumen catheter
central allows delivery of more concentrated formulations into high flow vessels
tolerance to peripheral is increased with feeds of low osmolarity and neutral pH and use of soft paediatric cannulae
parenteral feed preparations
TPN solns have mix of essential and non-essential AA, glucose, fat, electrolytes and micronutrients
Iso-osmotic lipid emulsions are used to provide an energy-rich solution and reduce irritation of veins. - lower conc of glucose to prevent hyperglycaemia or hyperosmolar dehydration
Vitamins including folic acid are infused with the solution, but vitamin B12 must be prescribed separately
delivery of parenteral nutrition
introduced at a low rate and gradually increased
TPN is usually deliverd at a continuous flow rate but cyclical regiemes may suit longer use
complications of parenteral nutrition
re-feeding syndrome
metabolic imbalance
catheter related complications
infection
liver and gallbladder dysfunction
hyperglycaemia - treatment with hypoglucaemic agents or insulin is often required
the nutrition is thrombogenic and an irritant to veins
re-feeding syndrome
in starvation intracellular electrolyte stores, esp phosphate, are depleted (even though serum conc is normal)
feeding stimulates cellular uptake of electrolytes -> electrolyte disturbances - hypophosphtaemia, low Mg, Ca, glucose and thiamine
clinical features appear in 4 days (non-specific)
rhabdomyolysis
red and white cell dysfunction
cardiac failure
hypotension
arrhythmias
resp failure
seizures
coma
sudden death
catheter related complications to parenteral feeding
immediate - related to insertion - haemorrhage, pneumothorax, haemothorax, arrhythmias, cardiac tamponade
embolism of IV line tip
long term - thrombosis, PE, pleural or pericardial effusion, subacute bacterial endocarditis, chylothorax and venopulmonary fistula
infection with parenteral feeding
staphylococcal (staph aureus, staph epidermidis and eneterococcal species are common
candida spp
Klebsiella pneumoniae
pseudomonas aeruginosa
IE
There must be strict adherence to aseptic and solution bags and giving sets must be discarded after 24 hours of use
look for spiking pyrexia and examine wound at tibe insertion point
stop PN, take line and peripheral cultures
give AB via line
if central venous line sepsis is suspected - remove line
thrombosis with parenteral nutrition
central vein thrombosis = PE or SVC obstruction
liver and gallbladder dysfunction in parenteral nutrition
majority of patients develop mild cholestasis - high transaminases and ALP
gallstones and gallbladder sludging may occur
indications for home parenteral nutrition
pts must have training and information before discharge
individual nutritional care plan is drawn up
pts must be competent in managing feeding systems and aware of the common problems
must be supported by skilled team
GPs must be closely involved to liase and recognose potentially life threatening complications
mechanism of refeeding syndrome
refeeding causes shift from fat to carbohydrate metabolism and increases insulin secretion
insulin -> cellular uptake of phosphate and K = hypophosphtaemia and hypokalaemia
clinical manifestations are from low ATP in metabolic pathways and low 2,3 diphosphoglycerate in erythrocytes = tissue hypoxia and impairment of myocardial contractility
Mx of refeeding syndrome
preventative
measured serum K+, phos, Mg, Ca and give IV replacement before refeeding
replace thiamine
daily multivitamin
increase calories gradually
give high dose Pabrinex during re-feeding window
metabolic imbalance with parenteral nutrition
refeeding syndrome
deranged plasma gluycose
hyperlipidaemia
deficiency syndromes
acid base disturbance - hypercapnia from excessive CO2 production
why are so many pts in hospitals malnourished
increased nutritional requirements - sepsis, burns, surgery
increased nutritional losses - malabsorption, output from stoma
decreased intake - dysphagia, nausea, sedation, coma
effect of treatment - nausea, diarrhoea
enforced starvation - prolongued periods NBM
missed meals - due to Ix
difficulty with feeding - lost dentures, no one available to assist
unappetizing food
how do you identify patients at risk of malnutrition
assess nutrition state using Malnutrition universal screening tool, and weight on admission - reassess weekly
Hx
- recent weight loss >20% accounting fro fluid balance
- recent reduced intake
- diet change - ie chnage in consistency
- nausea
- vomiting
- pain
- diarrhoea
O/E
- dehydration
- skin hanging off muscles
- no fat between fold of skin
- hair rough and wiry
- pressure sores
- sores at corner of mouth
- BMI <18.5kg/m2
- anthropomorphic indices - eg mid-arm circumference, skin fold measures and grip strength
Ix
- low albumin - but affected by other things
definitions of enteral nutrition
nutrition given into GIT
if possible give nutrition by mouth
indictations for enteral nutrition
all fluid diet can meet requirements
if danger of smoking/aspiration - semi-solid diet
early post op enteral nutrition has benefits and may reduce complications
what is tube feeding
liquid nutrition via a tube
NG - placed w/o guidance
NJ - require endoscopic placement
they can be inserted surgically ie gastrostomy/jejunosomy
typically initiated at a slow, continuous rate - less nausea and vomiting
may have shorter bolus feeds to free from pump
indication for NJ tuve
gastric outlet obstruction
delayed gastric emptying
post-gastrectomy
pancreatitis
contents of enteral feeds
polymeric feeds - undigested proteins, starches and long chain fatty acids (eg Nutrison standard, osmolite)
- Normally contain ~1kCal/mL and 4–6g protein per 100mL. Typical requirements met with 2L/24h.
elemental feeds - individual AA, oligo- and monosaccharides needing minimal digestion
guidelines for success for enteral feeds
fine bore NG tube
check in right place (NG - pH test, NJ - XR)
build up foods gradually to prevent diarrhoea and distension
weigh weekly
check blood glucose and electrolytes - monitor for refeeding syndrome
treat underlying conditions vigorously - sepsis can impede +ve nitrogen balance
complications of enteral feeding
tube complications
infection
gastro-oesophageal reflux and aspiration
gastrointestinal sx
re-feeding syndrome
NG tube complications with enteral feeding
- nasopharyngeal discomfort and later nasal erosions, abscesses and sinusitis.
- pharyngeal or oesophageal perforation, intracranial or bronchial insertion
- Longer use may cause oesophagitis, oesophageal ulceration and stricture
- Large stiff NG tubes are particularly unsafe in the presence of varices
Percutaneous gastrostomy or jejunostomy tubes complications
related to endoscopy
bowel perf, abdo wall or intraperitoneal bleeding
post-insertion complications include stoma site infections, peritonitis, peristomal leaks, dislodgement and gastrocolic fistula formation
gastro-oesophageal reflux and aspiration in enteral feeding
particularly in patients with impaired consciousness, poor gag reflex and when fed in the supine position
Reflux is more likely with accumulation of gastric residues.
gastrointestinal sx from enteral feeding
gut motility and absorption are promoted by hormones released during mastication, with co-ordinated stomach emptyinh and the presence of intraluminal nutrients
bypassed during enteral feeding = gastrointestinal symptoms such as abdominal bloating, cramps, nausea, diarrhoea and constipation
