Viva - Nutrition Flashcards
What % of patients are malnourished on arrival to ICU
50%
Problems with malnutrition in ICU
Altered immunity - susceptible to infection
Prolonged MV
Increased LOS
How to assess nutritional status of patients
Clinical - weight and weight loss (recent)
Co-morbid illnesses
Severity of illness
Evidence of GI dysfunction
MUST scoring
Upper arm circumf
Lab - anthropometry and albumin, confounded by oedema and acute phase changes
Ways to calculate energy needs
Indirect Calorimetry
Eqns - Harris-Benedict and Scholfied
Estimate based on IBW at 25-30kcal/kg/day (and add 20% in obesity)
Evidence on energy calculations
TIACOS - targeted energy based on indirect calorimetry
(Vs 25kcal/kg/day)
Calorimetry received more calories, increased MV and LOS
Trend to reduced mort
EDEN trial - Trophic feed (25% of target) for first 6 days changed vent length
Received fewer calories, but outcomes were as good as full feed
Protein needs and rationale
Catabolism of protein is rapid.
Protein needs are higher than energy needs, and not met by provision
Open abdo is source of nitrogen loss, estimated at 2g nitrogen/litre fluid
Weight based - 1.2 - 2g/day
Negative N2 balance - excreting more N than taking in —> muscle loss
Balance = (Total protein in / 6.25) - (UUN +4)
Where UUN is nitrogen excreted in urine in 24 hours (+4 is insensible)
Calorie split
Of the non protein calories
60% carbs
40% lipid
Requirements
Water. 30ml/kg Sodium 1-2mmol K 0.8 - 1.2 Ca. 0.1 Mg 0,1 Phos 0.4
Routes
Oral
NG
NJ
PN
Enteral is preferential unless a reason not to
Advantages of enteral
Physiological
Cheaper
No central line
GI tract integrity maintained - structure, perfusion, motility, less ulcers
Promotes immune function - mucosa assoc lymphoid, IgA
Advantages of parenteral
Don’t need a functioning GI tract
Can start early - no delay
Less interruptions
Disadvantage of Enteral
Needs a functioning tract
Diarrhoea
Risks with NG
Known to increase VAP risk
NG - sinusitis
Metabolic issues - electrolytes, high BM, refeeding
Disadvantages of parenteral
Not physiological
Hyper osmolar and irritant - central access
Systemic infection
Expensive
Hypercholesterolamia
Lipid emulsion - fatty liver
Evidence on route
CALORIES trial
No difference in mortality if fed enterally or parenteral lay
How to improve enteral delivery
Prokinetic - erythromicin/metoclop
Post pyloric feed - NJ/Jej
When to start feed
Enteral - within 24-48 hours of admission
After initial resus and haemodynamically stable
You don’t need flatus or bowel sounds to start
If EN is failing:
ESPEN - start TPN at 24 hours if EN not tolerated
ASPEN - after 7-10 days if unable to meet 60% of energy by enteral route
Evidence for early / late initiation of PN
EPaNIC - day 3 or day 8 PN
Late - increased survival, shorter MV and RRT
Components of TPN
Standard formulations
40% is non protein calories as lipid and 60% carbs
Amino acids/vitamins (B1, folate,; fat soluble ADEK)
Trace element (zinc, copper selenium)
Electrolytes
Immunomodulation
Glutamine
Maybe good in burns and trauma,
Facilitates nitrogen transport and reduce protein loss
REDOX trial - early glutamine in MOF was harmful, higher mortality
Arginine
NO prescursor
Improves macrophage and NK cells cytotoxicity
Harmful in sepsis
Omega 3 - anti-inflammatory
OMEGA trial stopped for futility, less vent free days
Selenium - scavenges oxygen free radicals
Non significant reduction in mortality
Glycaemic targets in non diabetic
NICE-SUGAR
Tight very conventional glucose control (tight 4.5 to 6) (convention less than 10
90 day mortality higher in tight group
More hypos
Previous small studies suggested tight might be better
Refeeding pathophysio
Happens when nutrition is restarted in patients have starved
Chronic malnutrition - protein and fat metabolism, and phosphate loss
Reintroduce carbs - anabolic state, insulin surge,
Re uptake of phosphate, magnesium and potassium
Effect of carb load in refeeding
Insulin release
Glycogen synthesis , Fat Synth, Protein Synth, (these need K, Mg, PO3)
PO3 uptake into cells
Hypophophate, Mg lost in urine
Form phosphorylated carb compounds —deplete ATP
Cellular dysfunction, decreased o2 delivery
Presentation of refeeding
CVS - heart failure and arrhythmia
GI - Vomiting, constipation, anorexia
Resp - resp muscle weakness
MSK - weak, osteomalacia
Neuro - ataxia delirium’s, coma, Wernickes (thiamine)
Metabolic - Low PO, MG, K, Ca, Thiamine
