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
- Renin stimulates production of angiotensin II which stimulates the release of what?
- What is resbsorbed because of this? and where?
- What is lost?
- Stimulates the release of aldosterone from the adrenal cortex
- Na+ and water resorption at the DCT
- K+ loss
- Increased cytokine release
such as? 3 - THese are produced from where? 4
- Response to tissue injury from what? 2
- Mediators of what? 2
- Interleukins (1-17) and
- interferons,
- tumor necrosis factor
- Produced from activated
- macrophages,
- fibroblasts,
- endothelial and
- glial cells - Response to tissue injury from
- surgery or
- trauma - Mediators of
- immunity and
- inflammation
What is the most important cytokine associated with surgery?
Interleukin 6
Interleukin 6
- Concentration peaks when?
- Degree of elevation depends on what?
- IL-6 and other cytokines cause the what?
- Concentration peaks 12-24 h post surgery
- Degree of elevation depends on the degree of tissue damage
- IL-6 and other cytokines cause the acute phase response
IL-6 and other cytokines cause the acute phase response
1. Production of acute phase proteins. What are these? 6
- Other effects? 5
- Cytokine production is limited by what? How?
- Fibrinogen,
- CRP,
- complement,
- alpha-2-macroglobulin,
- amyloid A and
- ceruloplasmin
- Other effects
- Fever,
- granulocytosis,
- hemostasis,
- tissue damage limitation and
- promotion of healing - Cytokine production is limited by cortisol
- Negative feedback
Name the Acute Phase Response in the following:
- Systemic? 2
- Bone marrow? 1
- Liver produces acute phase proteins?4
- Transport proteins? 4
- Changes in serum concentration of cations? 3
- Fever,
- changes in vascular permeability
- Increased neutrophils
- CRP,
- fibrinogen,
- alpha-2-macroglobulin,
- coagulation proteins
- Increase in ceruloplasmin
- Decrease in transferrin,
- album and
- alpha-2-macroglobulin
- Copper increases
- Zinc and
- iron decrease
Homeostatic Adjustments Initiated after Injury.
1. Pancreatic responses? 2
- Adrenal responses? 2
- Hypothalamus changes? 3
- Local inflammatory mediators? 3
- decreased insulin
- increased glucagon
- increased cortisol release and catecholamine release
- Elaboration of
- ACTH
- ADH
- GH - Cytokines
- Prostaglandins
- Platelet activating factor
- Opiods can suppress what?2
- Examples of these? 2
- Hormonal response to pelvic and abdominal surgery can be suppressed. How?
- What is the down side to this?
- Can suppress
- hypothalmic and
- pituitary hormone secretion - Ex: Fentanyl and morphine
- High dose fentanyl
- The down side: prolong recovery and increase the need for post-op ventilatory support
Anesthetic drugs
3
- Etomidate
- Benzodiazepines
- Clonidine
Describe the MOA of each of the following anesthetics:
- Etomidate?
- Benzodiazepines?
- Clonidine?
- Etomidate
- Suppresses cortisol production - Benzodiazepines
- May inhibit steroid production at the level of the pituitary - Clonidine
- Inhibit stress responses mediated by the sympathetic nervous system
Regional anesthesia
- AKA?
- What can this help reduce? 5
- What responses are unaltered?
- Regional anesthesia advantages?
4
- AKA: Epidural/spinal anesthesia
- can reduce the
- glucose,
- ACTH,
- cortisol,
- GH and
- epinephrine changes - Cytokine responses are unaltered
- Regional anesthesia can provide:
- Excellent analgesia,
- reduced thromboembolic complications,
- improved pulmonary function and
- reduced paralytic ileus
Other techniques for modification of the stress response. How do these help:
- Surgical technique?
- Nutrition? 3
- Hormone therapy?
- Maintenance of normothermia?
- Surgical technique
- Decreased cytokine release in minimally invasive surgeries
2. Nutrition Enteral feeding with -glutamine, -arginine, -omega-3 fatty acids has been shown to improve recovery
- Hormone therapy
- Insulin infusions +/- glucose may reduce excess protein breakdown - Maintenance of normothermia
- Reduces the metabolic response to surgery
- In general the magnitude and duration of the stress response are directly proportional to the what?
- What inhibits the stress response and can influence favorable postoperative outcomes?
- extent of surgical injury
2. Regional anesthesia
What is Dehiscence?
Wound rupture along the surgical suture
Dehiscence
- Patient risk factors? 5
- Surgical technique risk factors? 2
- Wound risk factors? 2
- Patient
- Age,
- obesity,
- diabetes,
- smoking,
- steroids - Surgical technique
- Poor knot tying or closure techniques
- Excessive tension - Wound
- Trauma or
- infection
Evisceration: What is it?
Complete dehiscence of an abdominal wound can lead to evisceration where the abdominal organs are protruding out of the wound
What is cellulitis?
An infection of the tissue just below the skin surface
What is gangrene?
Necrosis of the tissue occurs due to lack of adequate vascular supply or infection.
What are the forms of gangrene and describe them? 3
What is the other form?
Forms of gangrene
1. Wet: tissue infected, swollen, fetid smell
2. Dry: ischemia without infection
3. Gas: bacterial infection that produces gas in the tissues. Think clostridium perfringens
4. Other:
-necrotizing fasciitis.
Spreads deep along the tissue planes
- What is an Abscess?
- Usually caused by what?
- Describe this? 4
- Frequently associated with what?
- Collection of pus built up within the body tissue
- Usually caused by a bacterial infection but can also be sterile (irritant from injection)
- Painful,
- tender,
- fluctuant, and
- erythematous nodule
- Frequently associated with a pustule and surrounded by a rim of erythematous swelling
What is bacteremia?
The presence of bacteria in the blood
How can bacteremia enter the blood stream?
3
- From complications of infections (like pneumonia or meningitis)
- during surgery (especially when involving mucous membranes such as the gastrointestinal tract)
- due to catheters and other foreign bodies entering the arteries or veins (including during intravenous drug abuse)
- Septicemia: what is it?
2. AKA?
- Bacteremia that often occurs with severe infections (systemic signs and symptoms with organ failure)
- AKA bacteremia with sepsis
SIRS:
1. Clinical syndrome identical to sepsis characterized by what?
- Examples of noninfectious etiologies? 6
- dysregulation of inflammation but unlike sepsis can be caused by an infectious or noninfectious etiology
- autoimmune disorder,
- pancreatitis,
- vasculitis,
- thromboembolism,
- burns, or
- surgery
Early sepsis and SIRS are indistinguishable
SIRS is defined as two or more abnormalities in what? 4
- temperature,
- heart rate,
- respiration, or
- white blood cell count
Pathophysiology of sepsis/SIRS
Release of proinflammatory mediators in response to an infection (or other tissue insult) exceeds the boundaries of the local environment, leading to a more generalized response
Pathophysiology of sepsis/SIRS:
The cause may include?
2
- Direct effects of invading microorganisms or their toxic products
- Release of large quantities of
- proinflammatory mediators
- complement activation
Describe the normal inflammatory reaction to truma inflammation or infection? 2
- Inflammatory cascade
leads to - Proinflammatory activation followed by a reactive suppressing antiinflammatory response
Describe the Abnormal response to trauma, inflammation or infection? 2
- Inflammatory cascade
2. Excessive proinflammatory activation followed by excessive release of antiinflammatory mediators
Coagulation:
1. Which imflammation mediators affect this? 2
- What else do they affect? 2
- What does this result in? 1
- Cytokines IL-1 and TNF-alpha
- Affect endothelial surfaces
- Also cause decreased fibinolysis
- Resulting in expression of tissue factor
Coagulation:
1. Tissue factor initiates production of _________ and promotes coagulation
- Microvascular _______ then occurs
- thrombin
2. thrombosis
- Organ dysfunction as a result of what? 3
2. All organ systems may be affected. Most commonly involved include the what? 5
- Organ dysfunction as a result of
- Cellular injury
- Microvascular thrombosis
- Release of proinflammatory and antiinflammatory mediators
2. All organ systems may be affected most commonly involved include the -circulation, -lung, -gastrointestinal tract, -kidney, and -nervous system
Changes in sepsis:
- Vitals? 4
- AMS? 2
- CBC? 2
- CMP? 1
- Renal? 2
- What would indicate ischemic tissue? 4
- T over 38 less than 36
- HR over 90
- SBP less than 90 or drop of 40
- RR over 20
- AMS
- increased edema and ABG - Platelets less than 100, 000
- WBC over 12k or less than 4k
- Increased Bili
- Renal - acute oliguria
- CR- rise of 0.5
- Arterial hypoxemia
- increased lactate
- increased CRP
- increased procalcitonin
