The Physiologic Response to Surgery Flashcards
Physiological changes that occur during the stress response
4
- Hormonal
- Metabolic
- Immunological
- Hematological
Psychological and behavioral changes that occur during the stress response
- Psychological? 3
- Behavioral? 1
- Psychological
- Fatigue,
- malaise,
- depression - Behavioral
- Reluctance to move
Hormonal response to stress
1. Begins with the activation of the HPA axis and the ____________ nervous system
- They receive _______ nerve input from the area of trauma or injury
- The normal feedback mechanism then ____?
- sympathetic
- afferent
- fails
Sympathetic nervous system
1. Catecholemines are released from where?
- What increases from the presynapthic nerve terminals?
- This leads to? 2
- adrenal medulla
- Norepinephrine
- Leads to tachycardia and hypertension
Activation of the SNS has renal, pancreatic and hepatic effects
- Renal? 2
- Pancreatic? 1
- Hepatic? 3
- Renal
- Renin release causes conversion of angiotensin I to II
- Aldosterone release causing Na+ retention - Pancreatic
- Glucagon release - Hepatic
- Glucagon from the pancreas stimulates breakdown of glycogen in the liver & muscle
- Increased glucose and lactate concentration
- Mobilization of free fatty acids from lipid stores
Anterior Pituitary
- Controlled by what?
- Three hormones that are excreted here?
Posterior Pituitary
- Directly controlled by what?
- Hormone?
Anterior Pituitary
- Controlled by hypothalamic releasing or inhibiting factors (CRF, GHRF)
- ACTH,
- GH,
- Prolactin
Posterior Pituitary
- Directly controlled by the hypothalmus
- ADH
What changes with the following hormones during surgery:
- ACTH? Leads to? 2
- GH? Leads to? 2
- Prolactin? Due to?
- ↑ ACTH
- Leads to ↑release of cortisol and glucocorticoids from the adrenal medulla
- ↑ GH
- Which leads to ↑ blood sugar as it antagonizes insulin
- GH may also have a positive role in wound healing
- ↑ prolactin due to decreased prolactin inhibiting factor
How does ADH change in surgery?
Posterior
-Hypothalmic input causes ↑ ADH which leads to further ↑ in ACTH
- How does cortisol change following the start of surgery?
- Release stimulated by what?
- Max change when?
- Change to what level?
- Begins to increase rapidly following the start of surgery
- Release stimulated by ACTH
- Max increase in 4-6 hours
- Levels may increase 3-4 X normal
- Usually increased cortisol levels cause a decrease in the secretion of ______.
- How does this change in surgery?
- ACTH
2. but during and after surgery this feedback mechanism does not work and both ACTH and cortisol remain high
Functions of cortisol?
5
- Promotion of protein breakdown and gluconeogenesis
- Inhibits glucose use by the cells and increases blood glucose
- Promotes lipolysis leading to further increases in blood glucose
- Has glucocorticoid anti-inflammatory effects
- Has mineralocorticoid effects causing fluid retention and potassium loss
Insulin levels decrease
- Key _______ hormone?
- Synthesized and secreted from where?
- Promotes the uptake of _______ into muscle and adipose tissue
- Converts glucose into what? 2
- Inhibits protein what? 2
- Concentration decreases after induction of _________ and during trauma by inhibition of β cells in the pancreas by what?
- anabolic
- pancreas
- glucose
- glycogen and triglycerides
- catabolism and lipolysis
- anesthesia, the alpha-2-adrenergic effects of catecholamines
Glucagon increases
1. Produced by the ________ of the pancreas
- Promotes hepatic what?
- Increases ____________ from amino acids in the liver
- Has _______ activity
- Transient increase but doesn’t contribute much to the what?
- alpha cells
- glycogenolysis
- gluconeogenesis
- lipolytic
- hyperglycemic response
Thyroid hormones
1. What decrease after surgery and return to normal after several days?
- TSH concentrations decrease after the first ___ hours then return to normal
- How does it change during surgery?
- Changes related to what? 2
- Total and free T3
- 2
- Unaltered or decreased secretion in surgery
- catecholamines and cortisol
Summary of hormonal changes during surgery
Increased:
- Pituitary? 5
- Adrenal? 3
- Pancreatic? 1
- Other? 1
Unchanged?
1. Pituitary? 3
Decreased?
- Pancreatic? 1
- other? 3
Increased
- GH,
- ACTH
- Prolactin
- ADH
- B-endorphin
- Catecholamines Cortisol
- Aldosterone
- Glucagon
- Renin
Unchanged
- TSH,
- LH,
- FSH
Decreased
- Insulin
- Testosterone
- estrogen
- T3
Substrate metabolism is altered in response to stress
Such as? 3
- Carbohydrate
- Protein
- Lipid
Carbohydrate metabolism
1. Glucose homeostasis mechanisms are changed how in the perioperative period?
- Catabolic hormones promote glucose production and there is lack of insulin and peripheral insulin resistance. What are these hormones? 3
- The degree of hyperglycemia is related to what?
- ineffective
- Cortisol
- catecholamines
- Growth hormone
- The degree of hyperglycemia is relative to the severity of the surgery
Risks of prolonged perioperative hyperglycemia? 2
- Wound infection
2. Impaired wound healing
Increased cortisol and cytokine concentration
- Promotes what?
- Where?
- What may also be catabolized for essential amino acids?
- What are these amino acids used for?
- What protein specifically made by the liver is reduced and alters extra cellular volume?
- Promotes catabolism
- Primarily skeletal muscle
- Some visceral muscle may also be catabolized for essential amino acids
- These may be used by the liver for energy or to make new proteins, like acute-phase proteins
- Albumin production is reduced and alters extracellular volume
Protein metabolism:
1. Leads to what? 2
- Up to ___ kg/day of muscle loss post major abdominal surgery
- Can indirectly measure degree of protein loss by what in the urine?
- weight loss and
- muscle wasting
- 0.5
- nitrogen excretion
Lipid metabolism:
1. Lipolysis and ketone production due to? 4
- What are metabolized to free fatty acids and glycerol?
- Free fatty acids are oxidized to ______ in the setting of high glucagon and low insulin
- The converted to what? 3
Lipolysis and ketone production
- Due to
- increased catacholamines,
- cortisol and
- glucagon secretion
- And insulin deficiency - TGs
- acyl CoA
- B-hydroxybutyrate,
- acetoacetate and
- acetone
Water & Electrolyte metabolism
- ADH promotes what? 2
- Increased secretion for how long post op?
- Renin released from where?
- Stimulates production of what?
- Promotes
- water retention and
- concentrated urine - Increased secretion for 3-5 days post op
- Released from the juxtaglomerular cells of the kidney
- Stimulates production of angiotensin II