Nutrition in Surgical Patients
·
Perioperative mortality (e.g. in 30 days post surgery)
·
¯Healing
·
Respiratory infection
·
¯Immune function
·
Wound infection
·
Observe: thin?, how strong is
finger grip
·
History: intake over preceding
days compared to normal
·
Anthropomorphic measurement (BMI,
girth to hip ratio, skinfold thickness, compare actual to standardised 24 hour
urine creatinine excretion.)
·
Lab measurements (albumin,
transferrin – only for gross malnutrition)
·
Physiological assessment (PEFR,
FEV1, hand grip)
·
Adult needs 25 – 30 kcal/kg/day
· Typical diet gives: CHO – 40 – 60% (4 kcal/g)
o Fat: 20 – 45% (9 kcal/g)
·
Protein: 10 – 20 % (4 kcal/g)
·
Excess CHO stored as fat,
otherwise broken down to glucose
·
Short & medium chain FFA are
directly absorbed into the portal vein: so if gut is malabsorbing, give them
this – rapid and easy to absorb
·
During starvation, FFA saturate
Kreb‟s cycle ® ketones and acids
·
No body storage. Used, converted to energy or excreted
·
Maintained by protein intake of
0.8 – 1.0 g/kg/day
·
Nitrogen balance Þ nitrogen
in equal nitrogen out
·
Protein is 16% N2
·
Immediate use: liver and muscle
glycogen
·
Early starvation: Gluconeogenesis
from AA, glycerol and lactate. Leads to catabolism. Only supports CNS and RBCs
·
After few days: ¯metabolism, FFA used
by heart, kidneys and muscles
·
Prolonged starvation: brain uses
ketones. Protein catabolism as fat
stores used up
·
Basal Energy Requirement (BEE)
for otherwise well and sedentary ( when challenged by illness):
o Men = 66 + (13.7 * kg) + (5 * height in cm) – (6.8 * years)
o Women = 655 + (9.6 * kg) + (1.8 * height in cm) – (4.7 * age)
·
Protein/Calorie Requirements
·
Well nourished patients without
sepsis or injury: H2O and electrolytes OK for 5 days
·
Non-depleted post-operative
patients: 1.2 - 1.5 * BEE + 0.8 –
1.0 g protein/kg/day to prevent catabolism
·
Malnourished patients without
sepsis or injury: Cautious repletion – avoid refeeding syndrome due to
depletion of co-factors ® marked ¯ in PO4 and Mg – monitor
·
Nutritionally depleted patients:
1.5 – 1.8 g protein/kg/day + 1.5 * BEE
·
Patients with sepsis or injury:
Well nourished can manage without feeding for a few days. Malnourished need
feeding
·
Adult energy requirements: 40
Kcal/kg/day (approx. 2,500 Kcal per day)
·
Requirement in
sepsis, burns, trauma by 50 – 100 %
·
Protein requirement: 1.5g/kg/day
(approx. 105 g protein or 14g N2 per day)
·
Enteral much safer and less
expensive compared with parenteral
·
Delivered by: NG tube,
nasoduodenal tube (¯risk of aspiration), PEG, jejunostomy
·
Problems: aspiration, tube
blockage, diarrhoea due to intolerance/inadequate digestion
·
Feed by pump, starting slowly, at
30 – 45 degrees. Stop at night if they can tolerate increased flow during day
· Tradeoffs:
o When sick, ¯ motility and ¯emptying. Need to be minimal
volume but still flow through tube
o Don‟t include lactose as ¯lactase when sick. Lactose would ®
diarrhoea
o Osmolar
load ® diarrhoea. So need Mr
· 3 types:
o Intact nutrient formulas: Blenderised feedings (don‟t flow well),
lactose-free feedings (via tube), and nutrient-dense feedings (flavoured for
oral use)
o Pre-digested Nutrients (elemental diets): taste fowl, use NG tube
o Feeding modules: concentrated sources of one nutrient (e.g. protein, CHO
or fat)
·
For nutritional support when GI
tract can‟t be used
·
Via central line: Total
Parenteral Feeding (TPN) has very high osmolality. X-ray after insertion to
check no pneumothorax and line is outside pericardium (above anterior third
rib) to avoid cardiac tamponade following catheter erosion
·
Complete nutrition: electrolytes,
glucose, amino acids, fat emulsion, vitamins, etc. Fat a good way of giving
calories without glucose (which could ® diabetes)
·
Other major risk: sepsis. Test
for coagulase +ive staphylococci. Colony count should be 5 times higher in
central line sample than in peripheral blood
·
Metabolic problems common, e.g.
hyper or hypo glycaemia, acidosis, etc.
Alter constitution of TNP
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