Lecture 3 Flashcards
_____ is the Peripheral circulatory failure resulting in underperfusion of tissues. Characteristics include: ______ oxygen delivery to tissues.
_________ in anaerobic metabolism
Shock
Decrease oxygen delivery to tissues.
Increase in anaerobic metabolism
The three types of shock include:
Septic, Hypovolemic, and Cardiogenic
What happens to CI, PCWP, and SVR in septic shock?
Septic: Increased CI, Decreased PCWP, Decreased SVR
What happens to CI, PCWP, and SVR in hypovolemic shock?
Hypovolemic: Dec CI, Dec PCWP, Inc SVR
What happens to CI, PCWP, and SVR in cardiogenic shock?
Cardiogenic: Dec CI, Inc PCWP, Inc SVR
______ is the end result of many conditions. (ischemic heart disease, hypertension) and results in decreased ___________
CHF
intracellular cAMP
Decreased intracellular cAMP in CHF results in:
Downregulation of Beta receptors
Impaired coupling between beta receptors and adenyl cyclase
CHF responds to:
Responds to preload reduction, afterload reduction, and improved contraction
Low Cardiac Output Syndrome (LCOS) is seen in patients coming off of CPB and is a combination of:
Inadequate oxygen delivery to tissues Hemodilution Mild hypocalcemia Hypomagnesemia Kaliuresis Tissue thermal gradients Variable levels of systemic vascular resistance
Risk factors for Low Cardiac Output Syndrome (LCOS) include:
Risk factors: DM, Increasing age, female, pre-op decreased LVEF, increased duration of CPB
Treatment of Low Cardiac Output syndrome includes:
positive inotropes to increase the contractility of normal and stunned myocardium
hypotension, unlike CHF, responds poorly to vasodilators alone
Goal of Low Cardiac Output syndrome:
increase levels of O2 delivery
increase O2 consumption
cAMP Dependent Positive Inotropes include:
cAMP Independent Positive Inotropes include:
cAMP Dependent:
Beta Agonists
Dopaminergic Agonists
Phosphodiesterase Inhibitors
cAMP Independent:
Cardiac Glycosides
Calcium
Hemodynamic effects of positive inotropes include:
Increased contractility with:
Increased SV
Often decreased LVEDP
T/F In the failing circulation, effects of inotropes are likely to be more pronounced.
TRUE
Complications of Isoproterenol:
Tachyarrythmias
Complications of high dose NE and Epi for prolonged periods with persistent low CO:
will decrease perfusion to many tissue beds and contribute to renal failure
Use Digoxin cautiously in patients with:
hypokalemia, renal failure, bradycardia, drug interactions
Arrhythmogenic potential of positive inotropes:
Dobutamine<Isoproterenol
For Beta agonists cAMP increases Ca influx via slow channels and increases Ca sensitivity of Ca-regulatory proteins. This Increase the force of:
contraction and velocity of relaxation
Epinephrine is the prototypical catecholamine that stimulates:
Alpha 1, Beta 1, Beta 2
Low dose epinephrine stimulates _____ and is essentially a _______
Beta 2, vasodilator
Intermediate dose epinephrine stimulates _____, which ___________
Beta 1
which is an inotrope
increases HR and contractility and increases CO and increases automaticity
High dose epinephrine stimulates ____ and is a potent _______.
Alpha 1
Vasoconstrictor
Most potent activator of Alpha-1 receptors
Potent vasoconstrictor including cutaneous, splanchnic and renal vascular beds
Used to maintain myocardial and cerebral perfusion
Increases Aortic dBP.
Reflex bradycardia can occur
Vasoconstrictor.
Norepinephrine is primarily an __________
Alpha 1 agonist
Beta-1 effects are overshadowed by its Alpha-1 effects
Beta-2 effects are minimal
T/F: Cardiac output decreases at low doses, but at higher doses may increase because of increased afterload and baroreceptor-mediated reflex bradycardia
FALSE!
Cardiac output may INCREASE at low doses, but at higher doses may DECREASE because of increased afterload and baroreceptor-mediated reflex bradycardia
NE binds to _________ more readily than ____
Binds to Alpha-1, Alpha-2 and Beta-1 receptors more readily than Beta-2