Flashcards in Metabolic Response to Trauma and Critical Illness Deck (51)
what are the causes of hypermetabolic response?
what is the neurohormonal arm?
what is the inflammatory arm?
what does aldosterone do?
cause renal sodium retention
what does antidiuretic hormone (ADH) do?
stimulates renal tubular water absorption
what does ACTH do?
acts on adrenal cortex to release cortisol (glucocorticoids) to stimulate lipolysis and mobilize aa from skeletal muscles
what do catecolamines do?
epinephrine and norepinephrine - from adrenal medulla to stimulate hepatic glycogenolysis
what cytokines are released by phagocytes in response to tissue damage, infection, inflammation?
tumor necrosis factor (TNF)
what type of effect do eicosanoids have?
local (paracrine) effect
what do cytokines promote and how?
wound healing by ingrowth of fibroblasts
what do cytokines stimulate?
what do cytokines increase and facilitate?
increase white cell count and facilitate white cell migration
cytokines localize what?
what does mobilization of aa from cytokines do?
stimulate the acute phase of protein synthesis by the liver
what is responsible for fever (increased metabolic rate)?
what are the three phases following trauma?
ebb phase / unresuscitated phase
flow phase - adrenergic-corticoid phase
recovery phase / convalescent phase / anabolic phase
in the ebb phase what are the immediate responses following injury?
in the ebb phase, decreased CO can result in?
lactic acidosis (metabolic acidosis) due to decrease tissue oxygenation
in the ebb phase, what does decreased oxygen consumption lead to?
decreased metabolic rate
in the ebb phase, what does lower metabolic rate correspond to?
lowered body temp
in the ebb phase, what happens when insulin levels drop?
glucogon and epinephrine are elevated!
In the flow phase, what happens
restore o2 transport
increase body temp
increase energy expenditure
increase in circlating catecholeamines/INSULIN/ glucagon/cortisol and inflammatory cytokines
In the flow phase, there is a marked increase in what?
glucose production --> hyperglycemia
protein catabolism begins
circulation of free FA
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
what is the metabolic rate proportional to?
the extent and severity of the injury
- the more severe the injury the greater the metabolic rate
what needs increase as the severity of the illness increases?
energy needs - need to give more food/nutreints!
what are the changes in carb metabolism in Ebb phase?
due to presence of epinephrine and glucocorticoids that stimulate glycogenolysis and gluconeogenesis
LOW INSULIN LEVELS WITH slightly increased glucose production
what are the changes in carb metabolism in flow phase?
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!)
what might patients with type I DM have in the flow phase?
ketoacidosis because of insulin resistance
what defines insulin resistance?
insulin requirement is greater than 200 units per day
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
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
what happens to TAGs with severe injury?
TAGs are mobilized because epinephrine activate HS lipase
patients with major trauma rapidly deplete what?
their fat stores
what is not observed in patients with major trauma? why?
-may be due to high insulin levels
-peripheral tissues use free FA or KB
- ketogenesis is inversely proportional to severeity of injury
protein catabolism is what to the severeity of the injury?
in both starvation and critical illness, they are states of _____ nitrogen balance.
which state is protein depletion more severe?
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
what type of nitrogen balance is in flow phase?
what is the major source of nitrogen following extensive injury?
-glutamine and alanine are majority of release aa used for hepatic gluconeogenesis + maintain immune system + acute phase protein sysntehsis by liver
what are the acute phase protein?
alpha 1 antitrypsin
synthesized by the liver in response to inflammation
what are acute phase reactants used for?
monitor progress and prognosis of inflammation
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)
when greater than 20-30% of body protein is depleted, its what?
what are the main features of flow phase?
involves most metabolic pathways
increase dpi, glucocorticoids, cytokines
accelerated metabolic rate (hypermetabolic state)
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
what are the changes with lipid metabolism in flow phase?
increase circulating serum free fatty acid levels
what are the changes in carb metabolism in flow phase?
increased gluconeogenesis by liver
what are the main objectives of nutritional support?
slow down loss of protein /increase protein synthesis
supplement with GLUTAMINE,argentine for enhanced immune function