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61 Cards in this Set
- Front
- Back
Anesthesiology has been described as the practice of ____ medicine.
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autonomic nervous system (ANS)
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Preoperatively, what is the most practical bedside test to evaluate the ANS function?
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recording SBP and HR response when patient changes from supine to upright posture.
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in regard to SBP & HR, ANS dysfunction is suspected when what 2 things occurs?
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1.orthostatic hypotension (SBP decrease more than 30mmHg)
2.absence of an increase in HR on assuming the upright posture. |
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The central ANS includes?
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1.hypothalamus (stress responses, SBP control, temperature regulation)
2.medulla and pons (hemodynamic and ventilatory control) |
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Preganglionic fibers of the SNS arise from ?
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thoracolumbar portions of the spinal cord
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Preganglionic fibers in the PNS arise from ?
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craniosacral portions of the spinal cord
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the small amount of norepinephrine that is not subjected to reuptake into the postganglionic nerve endings, is subjected to what?
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deamination in the cytoplasm by the enzyme monoamine oxidase
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are postganglionic fibers of SNS distributed all over body or limited at effector organs?
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distributed all over body
mass reflex |
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are postganglionic fibers of PNS distributed all over body or limited at effector organs?
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limited at effector organs
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what are postganglionic fibers of PNS that release ACh called?
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cholinergic
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what are postsynaptic receptors that respond to ACh 2 classifications?
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nicotinic or muscarinc
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Action of acetylcholine at responsive receptors is terminated by ?
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hydrolysis of this neurotransmitter by the enzyme acetylchoninesterase (true cholinesterase)
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Beta 1 effector organs & responses (2)
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1.Heart
--increased HR, contractility, conduction velocity 2.Fat cells --Lipolysis |
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Beta 2 effector organs & responses (6)
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1.Blood vessels (especially skeletal and coronary arteries)- dilation
2.Bronchioles - dilation 3.Uterus - relaxation 4.Kidneys - renin secreation 5.Liver - Gluconeogenesis 6.Pancreas - insulin secretion |
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Alpha 1 effector organs & responses (4)
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1.Blood vessels - constriction
2.Pancreas - inhibition of insulin secretion 3.Intestine - relaxation 4.bladder - consgtriction of spincter |
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Alpha 2 effector organs & responses (3)
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1.Postganglionic (presynaptic sympathetic nerve endings) - inhibition of NE release
2.CNS (postsynaptic) - increased K+ conductance 3.Platelets - aggregation |
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Dopamine 1 effector organ & response
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Blood vessels - dilation
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Dopamine 2 effector organ & response
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Postganglionic (presynaptic) sympathetic nerve endings - inhibition of NE release
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Muscarinic effector organs & responses (5)
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1.Heart - decreased HR, contractility, conduction velocity
2.Bronchioles - constriction 3.Salivary glands - stimulation of secretions 4.Intestines - constriction, relaxation of sphincters, stimulation of secretions 5.Bladder - contraction, relaxation of sphincter |
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Nicotinic effector organs & responses (2)
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1.Neuromuscular Junction - skeletal muscle contraction
2.Autonomic Ganglia - SNS stimulation |
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________ are compounds with hydroxyl groups on the 3 and 4 positions on the benzene ring of phenylethylamine.
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Catecholamines
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Endogenous catecholamines are ?
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dopamine, norepinephrine, and epinephrine
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Cathecholamines that do not occur endogenously are ?
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isoproternol and dobutamine.
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Catecholamines are predominantly effect which system?
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the CV system
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List from most to least the effect of dopamine on MAP, HR, CO, SVR, Renal blood flow, Cardiac dysrhythmias
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1.CO, renal blood flow
2.SVR, MAP, HR, cardiac dysrhythmias |
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List from most to least the effect of NE on MAP, HR, CO, SVR, Renal blood flow, Cardiac dysrhythmias
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1. SVR, MAP
2.cardiac dys 3.decreased HR, CO, renal BF |
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List from most to least the effect of epinephrine on MAP, HR, CO, SVR, Renal blood flow, Cardiac dysrhythmias
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1.cardiac dys
2.HR, CO, SVR 3.MAP 4.decreased renal BF |
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List from most to least the effect of isoproternol on MAP, HR, CO, SVR, Renal blood flow, Cardiac dysrhythmias
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1,HR, CO, cardiac dys
2.decreased MAP, SVR, renal BF |
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List from most to least the effect of dobutamine on MAP, HR, CO, SVR, Renal blood flow, Cardiac dysrhythmias
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1.CO
2.Renal BF 3.MAP, HR 4.decreased SVR, cardiac dys |
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what does dopmaines effects depend on?
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dose
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which receptors does dopamine stimulate?
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Depending on dose, directly stimulates dopamine, beta, and alpha adrenergic receptors.
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what makes dopamine unique among this class of drugs?
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ability to stimulate dopamine receptors and redistribute blood flow to the kidneys
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Renal effects at what dose of dopamine? and what are the renal effects?
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< 3mcg/kg/min
aldosterone secretion & increased BF to kidneys resulting in increased UOP |
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Beta adrenergic stimulation at what dose of dopamine? and what are the effects?
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(3-10 mcg/kg/min)
1.myocardial contractility w/o marked changes in HR and SBP 2.evoking the release of endogenous stores of norepinephrine, which predisposes to cardiac dysrhythmias. |
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when is the secondary release of NE not effective with dopamine administration?
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when cardiac catecholamine stores are depleted, as with chronic CHF
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Beta and alpha adrenergic agonist effects at what dose of dopmaine?
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10-20 mcg/kg/min
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Predominate alpha adrenergic effects at what dose of dopamine?
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>20 mcg/kg/min
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IV infusion of dopamine interferes with what mechanism related to respiratory system? why?
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ventilatory response to hypoxemia
it's an inhibitory neurotransmitter at carotid bodies |
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High dose dopamine can inhibit ?
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release of insulin, leading to hyperglycemia.
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Most often used in clinical situations characterized by?
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1.decreased CO
2.SBP 3.increased LVEDP 4.oliguria |
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Extravazation of dopamine produces? and what's the tx?
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intense local vasoconstriction
treated with phentolamine |
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Norepinephrine
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an endogenous neurotransmitter for alpha and beta adrenergic receptors
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clinial indications for NE?
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hypotension
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MOA of NE maintenance of BP?
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vasoconstriction, increased SVR
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which effects are greater with NE, beta 1 or alpha 1? and where?
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alpha 1 > beta 1
in the peripheral vasculature |
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why might CO be decreased despite increased SBP when NE is administered?
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1.increased ventricular afterload
2.baroreceptor-mediated reflex bradycardia |
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are the beta 2 effects of NE significant?
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no mininmal
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Used for treatment of refractory hypotension as may occur in early period following ligation of vascular supply to a phenochromocytoma.
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NE
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Epinephrine stimulates which receptors?
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alpha-1, beta-1, and beta-2 receptors
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where does vasoconstriction occur when epi stimulates alpha 1 receptors?
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skin, mucosa, hepatorenal vasculature
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where does vasodilation occur when epi stimulates beta 2 receptors? net effect?
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skeletal muscles
decreased SVR and a preferential distribution of CO to skeletal muscles |
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Effect of epi on Beta-1 receptor?
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1.increase HR
2.increased contractility 3.increased CO 4.increased automaticity (manifest as cardiac irritability in form of PVC’s) |
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what effect does epi have on renal blood flow?
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greatly decreased
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which catecholamine has the most significant effect on metabolism of all the catecholamines?
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epinephrine
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what in response to surgical stimulation is a likely explanation for the hyperglycemia that is often observed in perioperative period?
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Epinephrine release
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Subcutaneous epinephrine is also used in combination with local anesthetics. Why?
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to decrease systemic absorption and provide local hemostasis
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Along with oxygen, what is the most important pharmacologic treatment of cardiac arres?
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epinephrine
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Isoproterenol
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a synthetic catecholamine with potent stimulant effects on beta-1 and beta-2 receptors. No alpha-1.
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Effects of Isoproterenol
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1.Myocardial contractility
2.increased CO 3.increased HR 4.increased SBP 5.increased cardiac automaticity 6.decrased SVR 7.decreased diastolic BP |
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regarding isoproterenol, Excessive tachycardia and simultaneous diastolic hypotension may ?
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decrease coronary blood flow at time myocardial oxygen requirements are increased by tachycardia.
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Clinical uses of Isoproterenol ?
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1.increase HR after heart transplant or complete heart block (chemical packmaker).
2.in patients with valvular heart disease to decrease PVR |