test 3 cont Flashcards
vasopressin also called
-anti-diuretic hormone
vasopressin does what
Regulates renal water excretion (POTENT)
high concentrations of vasopressin causes
increase peripheral vascular resistance
decrease cardiac contractility
decrease coronary blood flow
increase renal vascular resistance (hold onto water)
decrease renal blood flow
Stimulates release of von Willebrand factor which is key in the clotting cascade (improve hemostasis)
What Stimulates Vasopressin Release?
increase plasma osmolarity
decrease blood volume or decreased blood pressure
Hypoglycemia
Angiotensin
Stress
Pain
General anesthesia & surgery (MODERATE)
Angiotensin converting enzyme (ACE) inhibitors
what happens to ADH when put on bypass
huge increase in ADH with bypass
the increase in ADH because of bypass may be initiated by
↓ in Blood volume with CPB initiation
↓ LA pressure (volume depletion)
Transient Hypotension
prevention of increase in vasopressin on pump
Anesthesia with large doses of synthetic opioids but doesn’t completely prevent
-HELP DECREASE THE MAGNITUDE OF THE INCREASE, BUT NOT ELIMINATE THE INCREASE COMPLETELY!
Catecholamines
Epinephrine and norepinephrine released from the adrenal medulla and Peripheral sympathetic & central nerve terminal (NE
only)
Potent vasoconstrictor (Alter intra-organ blood flow)
What happens to catecholamines during CPB
Overall increase during cardiopulmonary bypass
Epinephrine - increases 10 fold over Pre-CPB
Norepinephrine - increases 4 fold over Pre-CPB
How do you decrease the response of the catecholamines during CPB
-decrease the temp
prevention of the catecholamines
Deep anesthesia versus light
Propofol infusion during bypass versus single bolus injection diazepam
High dose opiod general anesthesia (fentanyl or sufentanil) plus thoracic epidural versus high dose opiod anesthesia alone
-ANESTHESIA PLAYS A MAJOR ROLE
-magnitude of increase can be reduced but not eliminated
epinephrine concentrations max
- right before we come off bypass
- eliminate spike using pulsatile flow
norepinephrine concentrations max
- after bypass
- pulsatile perfusion decrease peak
Adrenal Cortical Hormones
Cortisol
Adrenocorticotropic hormone
Cortisol
Corticosteroid
Released in response to stress
Increases blood sugar
-sugar in liver as glycogen
Adrenocorticotropic hormone
Corticotropin
-initiates the release of corisol
initiation of bypass, what happens to [] of Cortisol and
Adrenocorticotropic Hormone
-increase
Increase in Cortisol and
Adrenocorticotropic may be attenuated by
Deeper levels of anesthesia
Addition of thoracic epidural
Glucose is a carbohydrate metabolism regulated by
insulin glucagon cortisol growth hormone epinephrine
on bypass, what happens to: glucose and insulin
Glucose concentration increases
Insulin levels decrease (insulin resistance)
All influenced by hypothermic bypass
atrial natriuretic factor
Release triggered by atrial distention
- released by cardiac atria
- helps control fluid balance
what does the renin-angiotensin-aldosterone do
Regulates arterial blood pressure, intravascular volume, electrolyte balance
when is renin released and what secretes it?
Juxtaglomerular apparatus secretes renin In response to: -sodium depletion -decreased blood volume -reduced renal perfusion
renin does what to angiotensinogen
-catalyzes conversion to angiotensin I (increased activity) (happens in blood)
angiotensin I to II via
- angiotensin-converting enzyme (ACE)
- happens in the lungs
- lose this whole process on bypass
aldosterone stimulates the reabsorption of what
-sodium-> increasing volume
angiotensin II does what
increased blood pressure by direct vasoconstriction
stimulates release of aldosterone for adrenal glands
aldosterone does what
stimulates reabsorption of sodium and secretion of
potassium and hydrogen ion by renal distal tubules
eicosanoids are what
-prostaglandins and thromboxanes
what is PGE and what does it do
- vasodilator
- prostaglandin
what is TXA2
-platelet aggregator and a vasoconstrictor
Histamine is
Potent vasodilator
what stimulates histamine release
opioids (morphine / meperidine) muscle relaxants (tubocurarine) antibiotics heparin protamine [] increases with heparin given
what causing an increase in the release of calcium
decreased ionized calcium concentration
Hypocalcemia
hypomagnesemia
On bypass, changes in calcium are caused by
Type of priming solutions
Blood products
Use of albumin
Magnesium
Second most abundant intracellular cation
- doesn’t have a hormone to increase it’s levels
- keep membrane stability
- not enough magnesium leads to things not working as good as they should
what does calcium and magnesium bind to?
-albumin
what happens to [magnesium] while on bypas
Decreases during bypass Hemodilution Chelation by albumin, blood products Once low – takes a while to come back up No hormonal support to increase -HELPS SUPPRESS ARRHYTHMIAS
Potassium levels
shoot for 4.5
