Nutritional support in trauma Flashcards
When does phase 1 occur? What is it? For how long?
2-6 hours after trauma, shock, for 24-48hrs
What does phase 1 involve release of?
Cortisol, catecholamines, cytokines
4 things that happen in phase 1
HR and respiratory rate increased, peripheral vasoconstriction, hypovolaemia
When does phase 2 happen, what is it called?
2 days after
Catabolic
3 things released in phase 2?
Cortisol (stimulated by ACTH)
Catecholamines
Glucagon
5 things that happen in phase 2
Increased O2 consumption Increased metabolic rate Increased glycolysis Increased lipolysis Negative nitrogen balance (muscle broken down to AAs)
Phase 3 name and when?
Anabolic, weeks after (or 3-8 days after minor surgery) lasts for a few weeks/months
4 things that happen in phase 3
Protein synthesis
Normal nitrogen balance
Fat stores
Muscle strength
10 affects of cytokines
chemotaxis Vasodilation cell adhesion proteins catabolic (metabolic effect) Acute phase proteins T and B cell activation Anorexia Endocrine - stimualtes catabolism (catecholamines, cortisol, glucagon) and inhibits anabolism (GH and insulin decreased) Fever Fibroblast production
Brain obligate substrate?
Glucose
How many mins of circulatory failure can the brain survive?
2 mins
What does the CNS switch to metabolising in the absence of glucose?
Ketones
What do the kidneys and liver metabolise?
Fatty acids and AAs
What does skeletal muscle metabolise?
Fatty acids and glycogen stores
If glucose and O2 supply interrupted, what 3 stages of metabolism occur?
- glycogenolysis (glycogen to glucose) max 24hrs
- gluconeogenesis (muscle to AAs to glucose and lactate)
- lipolysis and ketogenesis (free fatty acids to acetyl coA to ketones (acetoacetate and hydroxybutarate)
Ketosis causes
Diuresis
Aerobic resp 1 mol glucose –> ? mol ATP?
36
Anaerobic resp 1 mol glucose –> ? mol ATP?
2
In an anaerobic response what happens to pyruvate?
Reduced to lactate
What is lactate a marker of?
Low pH
Why proteolysis increased in trauma?
AAs needed to create inflammatory modulators and gluconeogenesis
What are markers of increased proteolysis?
Increased plasma ammonia, increased N2 loss in urine
Will adequate calories prevent muscle breakdown in trauma patients?
No, cytokine secretion stimulates muscle breakdown regardless
How might a trauma patient get pneumonia?
Muscle breakdown = respiratory muscle weakness
Increased lactate is a marker of?
Tissue hypoxia.
Also prognosis
What affect does immobilisation have on loss of substances?
Increases loss e.g. Ca, P, Mg
Is parenteral or gut-involved feeding better?
Gut
What is primary malnutrition?
Starvation or dietary deficiency of specific nutrients
What is secondary nutrition?
Nutrition present in adequate amounts but appetite suppressed/absorption failure/increased demand
What is refeeding syndrome?
Sudden change from catabolic to anabolic state, insulin produced which = cellular uptake of K+, P, Mg for glycogen, fat and protein synthesis. Results in serum electrolyte defecits e.g. hypokalaemia –> cardiac arrhythmia
