Metabolic Response to Trauma and Critical Illness Flashcards Preview

Biochemistry Post Midterm > Metabolic Response to Trauma and Critical Illness > Flashcards

Flashcards in Metabolic Response to Trauma and Critical Illness Deck (51):
1

what are the causes of hypermetabolic response?

sepsis
fractures
stress
major surgery
burns
trauma

2

what is the neurohormonal arm?

catecholamines
glucocorticoids
glucagon
ADH
aldosterone

3

what is the inflammatory arm?

cytokines
complement
eicosanoids
PAF

4

what does aldosterone do?

cause renal sodium retention

5

what does antidiuretic hormone (ADH) do?

stimulates renal tubular water absorption

6

what does ACTH do?

acts on adrenal cortex to release cortisol (glucocorticoids) to stimulate lipolysis and mobilize aa from skeletal muscles

7

what do catecolamines do?

epinephrine and norepinephrine - from adrenal medulla to stimulate hepatic glycogenolysis
fat mobilization
gluconeogenesis

8

what cytokines are released by phagocytes in response to tissue damage, infection, inflammation?

interleukins
tumor necrosis factor (TNF)
eicosanoids

9

what type of effect do eicosanoids have?

local (paracrine) effect

10

what do cytokines promote and how?

wound healing by ingrowth of fibroblasts

11

what do cytokines stimulate?

angiogenesis

12

what do cytokines increase and facilitate?

increase white cell count and facilitate white cell migration

13

cytokines localize what?

the wound!

14

what does mobilization of aa from cytokines do?

stimulate the acute phase of protein synthesis by the liver

15

what is responsible for fever (increased metabolic rate)?

cytokines

16

what are the three phases following trauma?

ebb phase / unresuscitated phase
flow phase - adrenergic-corticoid phase
recovery phase / convalescent phase / anabolic phase

17

in the ebb phase what are the immediate responses following injury?

hypovolemia
shock
tissue hypoxia

18

in the ebb phase, decreased CO can result in?

lactic acidosis (metabolic acidosis) due to decrease tissue oxygenation

19

in the ebb phase, what does decreased oxygen consumption lead to?

decreased metabolic rate

20

in the ebb phase, what does lower metabolic rate correspond to?

lowered body temp

21

in the ebb phase, what happens when insulin levels drop?

glucogon and epinephrine are elevated!

22

In the flow phase, what happens

fluid resuscitation
restore o2 transport
increase CO
increase body temp
increase energy expenditure
increase in circlating catecholeamines/INSULIN/ glucagon/cortisol and inflammatory cytokines

23

In the flow phase, there is a marked increase in what?

glucose production --> hyperglycemia
protein catabolism begins
circulation of free FA

24

what is the flow phase characterized by and how can that be mesured?

increase in metabolic rate (hypermetabolic state)
measured by CO2 produced/min
o2 consumed /min

25

what is the metabolic rate proportional to?

the extent and severity of the injury
- the more severe the injury the greater the metabolic rate

26

what needs increase as the severity of the illness increases?

energy needs - need to give more food/nutreints!

27

what are the changes in carb metabolism in Ebb phase?

hyperglycemia
due to presence of epinephrine and glucocorticoids that stimulate glycogenolysis and gluconeogenesis

LOW INSULIN LEVELS WITH slightly increased glucose production

28

what are the changes in carb metabolism in flow phase?

still hyperglycemia
normal insulin levels - insulin resistance!
increase hepatic gluconeogenesis from aa from muscle
increase uptake of glucose by muscles and adipose tissue (GLUT 4 less active!)

29

what might patients with type I DM have in the flow phase?

ketoacidosis because of insulin resistance

30

what defines insulin resistance?

insulin requirement is greater than 200 units per day

31

where is the glucose produced mainly used?

by the injured tissue /wound - the wound and hypoxic tissue convert glucose to lactate via anerobic glycolysis which goes to liver via cori cycle

32

why is there lactic acidosis in critically injured?

because there in impaired oxygenation to tissues which forces the body to use anerobic glycolysis which produces lactate
if there is impaired blood flow what results in impaired cori cycle and you get lactic acidosis which is metabolic acidosis

33

what happens to TAGs with severe injury?

TAGs are mobilized because epinephrine activate HS lipase

34

patients with major trauma rapidly deplete what?

their fat stores

35

what is not observed in patients with major trauma? why?

ketosis

-may be due to high insulin levels
-peripheral tissues use free FA or KB
- ketogenesis is inversely proportional to severeity of injury

36

protein catabolism is what to the severeity of the injury?

proportional

37

in both starvation and critical illness, they are states of _____ nitrogen balance.

negative

38

which state is protein depletion more severe?

critical illness

39

what are the changes of protein metabolism in flow phase?

proteolysis increases due to glucocorticoids and insulin resistance

reduced protein synthesis and aa uptake by muscle

urine urea nitrogen excretion may be used to evaluate degree of muscle proteolysis

ubiquitin-proteasome system in skeletal muscle is active

40

what type of nitrogen balance is in flow phase?

negative

41

what is the major source of nitrogen following extensive injury?

skeletal muscle

-glutamine and alanine are majority of release aa used for hepatic gluconeogenesis + maintain immune system + acute phase protein sysntehsis by liver

42

what are the acute phase protein?

C-reactive proteins
alpha 1 antitrypsin

synthesized by the liver in response to inflammation

43

what are acute phase reactants used for?

monitor progress and prognosis of inflammation

44

what does excessive protein depletion result in?

impaired wound healing
decrease immune response
breakdown of gut-mucosal barrier
decrease mobility /respiratory effort
increase predisposition to infection and hyper metabolism (its a vicous cycle)

45

when greater than 20-30% of body protein is depleted, its what?

fatal

46

what are the main features of flow phase?

involves most metabolic pathways
increase dpi, glucocorticoids, cytokines
accelerated metabolic rate (hypermetabolic state)

47

what are the changes with nitrogen metabolism in flow phase?

negative nitrogen balance
muscle wasting due to excessive muscle proteolysis
increase urea excretion in urine

48

what are the changes with lipid metabolism in flow phase?

increase lipolysis
increase circulating serum free fatty acid levels
blunted ketogenesis

49

what are the changes in carb metabolism in flow phase?

insulin resistance
hyperglycemia
increased gluconeogenesis by liver

50

what are the main objectives of nutritional support?

fluid resuscitation
slow down loss of protein /increase protein synthesis
supplement with GLUTAMINE,argentine for enhanced immune function

51

which is better enteral (mouth) or paraenteral (IV)?

enteral - preserved intestinal mucosa better

BUT you must have functional GI tract!