Week 7- Parental nutrition Flashcards
what is malnutirion?
A deficiency or excess (or imbalance) of energy,
protein & other nutrients that causes measurable
adverse effects on the tissue/body size, shape,
composition & function & clinical outcome’
what are the consequences of malnutrition?
◼ Impaired immunity ◼ Decreased wound healing ◼ Increased complications ◼ Poor response to medical or surgical therapy ◼ Reduced growth or development of infant or child ◼ Death!
what is parenteral nutrio?
Intravenous administration of nutritionally balanced, physiochemical stable & sterile combination of: ◼ Water ◼ Amino acids ◼ Glucose ◼ Lipids ◼ Vitamins ◼ Trace elements ◼ Electrolytes Can fulfil the total nutritional requirements or can supplement an enteral feed or diet
what are the reasons for PN?
Short-term (inpatient) ◼ Post surgery if patient NBM (gut rest) > 7 days ◼ Obstruction in gut ◼ Severe shock or gut infection ◼ Malnourished or unable to eat Long-term (home PN) ◼ Non-functioning gut ◼ Not enough gut to function e.g. surgery Some patients can eat small amounts May or may not be permanent
WHAT IS A PATIENTS MAINTENCE FLUID?
Maintenance fluid = 1500ml + (20ml x each
kg of weight > 20kg)
what are some factors that would affet their fluid requirments?
Dehydration Fever Acute anabolic state High temperature Low humidity G.I. losses Burns/wounds Blood loss Fluid overload High humidity Blood transfusion Drugs Cardiac failure Renal failure
within protein how many amino acid are needed for protein synthesis and how many cannot be syntheised?
20 required for protein synthesis & metabolism
◼ 8 essential – cannot be synthesised
◼ 5 ‘conditionally essential’
Patient’s needs exceed the synthesis in clinically
stressed conditions
what is the adults maintenance calculation for energy a day?
-Majority of adults maintained on 25-35 nonprotein kcal/kg/day
what are the 2 types of sources of enegry iN PN?
glucose recommended source for carbs
lipids
why is glucose not used along for energy?
Glucose should NOT be used ALONE as the energy source because: ◼ Risk of hyperglycaemia ◼ Fatty infiltration of liver (as excess glucose is converted to fatty acids) ◼ Excessive CO2 production ◼ Excessive consumption of oxygen ◼ Essential fatty acid deficiency
how much lipid does a patient need for enegry a day?
Patients typically receive 2.5g
lipid/kg/day
what are the advantages of lipid emulsion for energy?
Large amount of energy in small amount of fluid
Allows peripheral administration
◼ Isotonic
◼ Venoprotective effect
Contains some fat-soluble vitamins (E and K)
Prevents/reverses essential fatty acid deficiency
what are the factors affecting micronutrients requirements?
-amount of trace element and vitamins
- Baseline nutritional state on starting PN
◼ Acute or chronic onset of illness
◼ Dietary history
◼ Duration & severity of inadequate nutritional intake
Increased loss:
◼ Small bowel fistulae/aspirate – rich in zinc
◼ Biliary fluid loss – rich in copper
◼ Burn fluid loss – rich in zinc, copper, selenium
Increased requirement:
◼ Increased metabolism
◼ Active growth
Organ function
◼ Liver failure – copper & manganese clearance
reduced
◼ Renal failure – aluminium, chromium, zinc &
nickel clearance reduced
what is the summary of the bags contents of a PN?
Amino acids (► Nitrogen/protein) Glucose + Lipids (► Energy + fluid) Trace elements Vitamins Electolytes
WHAT IS THE IMPORTANT INFORMATION ABUT PERIPHERAL ADMINISTRATION?
Considered first-line for parenteral feeding
Need good line care & low tonicity feeds
Patients can be successfully maintained for many
weeks
Can be complicated by phlebitis
Peripheral solutions have an osmolarity of
approximately 800mOsmol/L
◼ Infused slowly into a large blood vessel with good blood
flow
Indications
◼ Duration likely to be short-term
◼ Supplemental feeding
◼ Compromised access to central circulation
◼ No immediate facilities to insert central catheter
◼ High risk of fungal or bacterial sepsis
◼ Contraindication to central venous catherisation
Contra-indications
◼ Inaccessible peripheral veins
◼ High osmolarity of the PN formulation
High calorie/nitrogen requirements
WHAT IS A SCRATCH BAG?
when a patient has needs higher than the normal so need more stuff made from scrtah
what is the key infor for central aministeration?
Indicated when:
◼ Longer-term feeding is anticipated
◼ Peripheral route is inaccessible
◼ High tonicity formulations are required
Central solutions have an osmolarity of
approximately 2000mOsmol/L
Solution is rapidly diluted into a central vein
Inserted into either jugular or subclavian vein
Position confirmed by x-ray
Invasive & costly
- Always administered under control of
infusion pumps via a giving set
◼ Avoids overload of fluid, nutrition & electrolytes
Should be administered at room
temperature
◼ Remove from refrigerator 3 hours before
connection
what are the pharmaceutical issues for PN?
Complex preparations ◼ Contain over 50 chemical entities Stability advice from manufacturers & third party experts Issues ◼ Physical stability ◼ Chemical stability ◼ Microbial stability Visual inspection before release & administration to the patient
WHAT CAN BE A PHYSICAL STABILITY PROBLEM?
Precipitation
◼ Potential to infuse solid particles – fatal emboli
◼ Prescribed nutrients may not be infused
◼ Cannot be seen if bag contains lipid
Lipid destabilization
◼ Lipid globules may come together & coalesce
◼ Occlude the lung microvasculature – respiratory &
circulatory blockages
All PN fluids are passed through a filter when
infused into patient
WHAT CAN BE A PHYSICAL chemical PROBLEM?
Vitamins
◼ Readily undergo chemical degradation
◼ Often define the shelf-life of the formulation
◼ Vitamin C is least stable - used as a
marker for vitamin degradation
All bags are protected from light during
storage & infusion
WHAT CAN BE A PHYSICAL chemical PROBLEM?
Highly nutritious medium – potential for
microbial growth
Manipulations performed using validated
aseptic techniques
Staff are trained in aseptic technique when
connecting & disconnecting infusions
what is the nutritional assessment for needing PN?
Does the patient need nutritional intervention?
What are their nutritional requirements?
How long will the underlying disease last?
Can the enteral route be used?
What are the routes PN can be administered?
WHAT ARE THE MONITORING PARAMETERS FOR pn?
Clinical symptoms Temperature Blood pressure Fluid balance Weight, anthropometry Nitrogen balance Lipid tolerance Acid-base profile Liver function tests ◼ Abnormalities common Electrolyte profile Blood glucose Haematology, CRP Calcium, albumin
what are some complications for PN?
Line blockage
◼ Can be caused by:
Fibrin sheath forming around the line or a
thrombosis blocking the tip
Internal blockage of lipid, blood clot or salt &
drug precipitates
Line kinking
Blockage of a protective line filter
Line sepsis
Thrombophlebitis
Refeeding syndrome
◼ A metabolic complication occurring when the
infused nutrition exceeds the tolerance of a
previously malnourished patient
◼ Start feeding slowly i.e. one bag over 48 hours
instead of 24 hours
◼ Add thiamine if at risk
◼ Can cause significant mortality or morbidity
◼ Characterised by generalised fluid and electrolyte
imbalance in patients with a history of severe weight
loss or chronic starvation
WHAT DOES nice say for pn?
Nutrition Support in Adults
Consider PN in those who are malnourished or at
risk of malnutrition & either have:
◼ inadequate or unsafe oral and/or enteral nutritional
intake
◼ a non-functional, inaccessible or perforated (leaking)
gastrointestinal tract
Introduce PN progressively & monitor closely
◼ No more then 50% of estimated needs for 1st 24-48
hours
Stop PN when adequate oral and/or enteral
support is established
