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122 Cards in this Set
- Front
- Back
What is dehydation?
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loss of body water from ICF, ECF or both
caused by diarrhea, vomiting, polyuria, thirdspacing due to vasculitis, low protein and or increased hydrostatic pressure |
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What is water loss?
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animal losing fluid whether it be due to hypertonic, isotonic or hypotonic origin
Blood loss (vascular) resulting in hypovolemia can see hypovolemia and dehydration in a vomiting patient |
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What is hypovolemeia?
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loss of fluid from the vascular space
caused by severe dehydration, hemorrhage, inability to maintain vascular volume -vasculitis -low protein |
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What are crystalloids?
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Fluids used for maintainence, replacements and dextrose solution
Non-buffered Isotonic saline (0.9)* Ringers Solution * = HCO3- wasting Buffered Sodium lactate (lactated ringers) Sodium gluconate and acetate** solution (Normasol R and plasmalyte** ** = decreases acidosis |
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What are side effects of crystalloids?
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dilutional coaguopathy
hypoproteinemia Fluids overload (pulmonary edema) Careful with LRS and liver disease |
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What is dextrose?
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Maintenance solution that re rapidly converted to free water and allows it to be given without decreasing the osmolality of the solution
-patients with free water loss benefit from dextrose because it decreases the sodium in these hypernatremic patients -used to increase glucose does not me nutritional requirements of patient |
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What are Colloids?
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Solutions that pull water into the vascular space from other compartments
During shock restore the vascular volume resulting in decreased after load while maintaining preload, bp and blood flow to tissues -used in hypovolemic shock (shock doses are less than crystalloid) -albumin Hypertonic saline: -hydroxethyl starch -pentastarch -Dextians -Concentrated Albumin -Fresh Frozen Plasma |
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What are side effects of Colloids?
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Fluid overload- pulmonary edema
Synthetic coaguopathy Renal failure Allergic reactions to albumin in dogs from human source |
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What is vasodilatory shock?
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due to poor vascular tone and caused a decrease in vascular resistance and pooling of blood and decreased preload
decreased preload results in a decrease in cardiac output, decreased blood flow despite the decrease in vascular resistance |
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What are causes of vasodilitary shock?
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Drugs (acepromazine)
Toxins Inflammation Trauma |
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What are the clinical signs of vasodilatory shock?
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-increased heart rate (can be decreased in septic or cardiac patients)
-decreased CRT (due to vasodilation) -increase CRT (in septic shock due to excessive vasodilation) -bounding pulses initially and later weak -cool extremities or hypothermia -weak, dull, lethargic |
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What are the treatments for vasodilatory shock?
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Fluids (help increase preload)
-Crystalloid -Colloid -Hypertonic saline Vasopressures -excessive vasoconstriction decreases blood flow to less vital organs (GI) Treatment of other forms of shock |
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When are steroids used in shock?
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used in the treatment of renal insufficiency and anaphylactic shock
|
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What are treatments for anaphylactic shock?
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Fluids
Antihistamines Steroids Epinephrine |
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What is a treatment for adrenal insufficiency?
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Steroids necessary for vascular tone
otherwise contraindicated |
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What are vasopressors?
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drugs that restore the tone which increases preload and increase cardiac output
peripheral resistance will increase blood pressure and blood flow |
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What are examples of vasopressors?
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Dopamine
Norepinephrine Epinephrine Ephedine Phenylephedrine Vasopressin Nalaxone |
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What are the uses for low doses of Dopamine?
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dopamine receptor activation
causes vasodilation and improves GFR |
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What are the uses of mild doses of Dopamine?
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Beta 1 and 2 receptor activation
results in increase in cardiac contractility and vasocilation |
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What are the uses of high doses of Dopamine?
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Beta 1 and 2 receptors
Alpha 1 receptore increases contractility of the heart causes vasoconstriction improves vascular resistance in vasodilitory shock and therefore blood pressure and blood flow increases preload |
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What are the therapeutic uses of dopamine?
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cardiogenic shock
renal failure given IV wide distribution but does not cross BBB eliminated by plasma lover and kidney |
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What are the adverse effects of Dopamine?
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ventricular arrhythmias
Sinus side effects excessive vasocontriction vomiting and diarrhea extravascular administration can cause skin necrosis and sloughing |
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What are the effects of Norepiephrine?
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Alpha 1 and 2 receptor activation
Beta 1 receptor causes vasoconstriction, increased contractility can causes reflex bradycardia given IV |
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What are adverse effects of Norepinephrine?
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arrhythmias
no beta 2 activation = excessive vasoconstriction to non vital organs -can lead to GI ulcers |
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What are the effects of Phenylephrine?
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Alpha receptor activation
in vasocilatory shock this will increase resistance and therefore blood pressure and blood flow give IV metabolised in liver |
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What are the uses of Phenylephrine?
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treatment for vasodilitary shock
competes with Acepromazine (potent vasodilator) |
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What are drugs that should not be used in the reversal of acepromazine?
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Dopamine
Epinephrine use phenylephrine |
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What are the adverse effects of Phenylephrine?
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hypertension
reflex bradycardia CNS stimulation Excessive Vasoconstriction (no Beta 2) skin necrosis and skin sloughing at injection site |
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What are the actions of ephedrine?
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Alpha and Beta receptor activator
direct indirect - norepinephrine release long acting- given bolus |
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What are the effects of vasopressin?
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V1 receptor activation
causes vasoconstriction used in the treatment of vasodilatory shock and cardiac arrest |
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What are the uses of Naloxone?
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prevents exogenous opioid mediated vasodilation and used experimentally
|
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Tachyarrhythemias are the results of giving what vasoconstrictors?
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Isoproterenol
Epinephrine |
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What are the uses of Epiephrine?
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used in cardiac arrest and to increase vascular tone
works on both alpha and beta receptors 1 and 2 |
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What is the order of beta 1 effects in vasoconstrictors?
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Isoproterenol > Epinephtine > norephinephrine > Dopamine/Dobutamine
|
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What is heart failure?
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impaired pumping that decreases ventricular ejection and impedes venous return
|
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What is systolic failure?
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inability of the hear to eject blood properly and results in lethergy and exercise intolerace
See stenosis, decrease contractility and decreased heart rate known as cardiogenic Shock decreased O2 delivery Volumre overload |
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What is diastolic failure?
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inadequate ventricular filling resulting in congestion
see stenosis, hypertrophy and increased heart rate? known as congestive heart failure pressure overload |
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What are causes of hear failure?
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pressure overload
-left =aortic stenosis, systeming hyeprtension -right = heartworm, pumonic stenosis, pulmonary hypertension Volume overload -valvular insufficiency, PDA Primary Myocardial Disease -DCM, HCM, Myocarditis Myocardial infarction Pericardial disease Arrhythmias *cause determines treatment |
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What do you see with pressure overload changes on the heart?
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hypetrophy
-first helpful the harmful due to increased chamber size diastolic failure |
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What do you see with volume overload changes on the heart?
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results in eecentric hypertrphy and small amount of concentric hypertrphy
may improve diastolic function initially - later harmful due to increased stress and inadequate O2 delivery causing systolic function to worsen |
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What are primary myocardial failure changes?
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Poor contractility will reduce cardiac output and decrease atrial blood pressure and atrial blood flow
Usually associated with concentric hypertrophy – DCM Maybe due to decreased sympathetic tone or direct myocardial depression -drugs -toxins -inflammation |
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What are the compensation mechanisms for heart failure?
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Increase cardiac output
-hypertrophy -frank starlings law -increased heart rate and contractility Volume loss -ANP -BNP Volume gain -ADH -RAAS Vasoconstriction -Sympathetic stimulation -RAAS -Vasopressin |
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What is neurohormonal compensation for heart failure?
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-good initially
increasing preload via venous constriction will increase contractility resulting in increase arterial pressure not helpful in hypovolemia shock because volume is not the main problem |
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What is the effect of excessive venoconstriction?
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increase preload to the point that it hinders heart contractility
see congestion |
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What is the effect on sympathetic stimulation in heart failure?
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Norephinephrine may induce
-Apoptosis in cardiac myocytes -Myocyte hypertrophy -Ca overload in cardiac myocyte -Altered arterial baroreceptor reflex -Down regulation of Beta 1 -Decrease Ca uptake during diastole can result in decrease contractility due to decreased contractility die to decreased release of Ca during systole -Increased Norepilevels (CHF) -decrease heart rate variability is associated with a poor prognosis |
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What does chronic exposure to angiotensin II cause?
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Eccentric ventricular hypertrophy
Myocarial inflammation Myocardial necrosis Aldosterone may be involved -baroreceptor dysfuction -indiction of coronary inflammation -cardiac hypertrophy -cardiac fibrosis **renin active has been in some studies to be of prognosic value in heart failure |
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What are the consequences of stress and inflammation on the heart?
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TNF-alpha mabe produced by cardiac myocytes during heart failure due to hypoxia and mechanical stress and oxidative stress
-decrease cardiac contractility -ventricular hypertrophy -apoptosis IL-1, IL-2, IL-6 may also produced -inflammation -ventricular hypertrophy -Decreased contractility |
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What are clinical signs of diastolic heart failure?
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right sided
-organomegaly (distended abdomen) -Pleural effusion -Distended vessels Left sided -pulmonary edema -pleural effusion |
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What are clinical signs of systolic heart failure.
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Similar to other forms of shock
-similar to other forms of shick -exercise in tolerence -weak pulses -cold lips/hypothermia -increased CRT -pale/blue mucous membrane -decreased urination -weakness |
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What is the treatment for heart failure?
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supportive failure since mostlikely can not reverse the cause
fluids = hypovolemia vasopressors = for vasofilitory shock Positive inotropes are not always used in cardiogenic shock -HCM -valvular -Stenosis -DCM drugs are used to maintain blood flow by blood pressure |
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What are drugs used in emergency management of heart failure?
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Oxygen
Diuretics Vasodilators Postitive Inotropes |
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What diuretic is used in emergency heart failure?
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Furosemide
inhibits Na-K 2Cl symporter in aLOH decreases preoload and decreases hydrostatic pressure used of congestive heart failure |
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What are adverse effects of Furosemide?
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cardiac arrhythmias
hyperglycemia ototoxicty GI disturbance Anemia Leukopenia |
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What vasodilators are used in emergency heart failure?
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Nitroglycerin
Nitroprusside Hydralazine Isorbide dinitrate |
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What are the effects of arterial dilators? venous vasodilators
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Decrease afterload
Decrease preload |
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What is Nitroglycerin?
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Drug used in emergency heart failure
Venous vasodilator by NO formation decreases preload |
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What is Nitroprusside?
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Drug used in emergency heart failure
arterial and venous vasodilator short acting decreases preload and afterload |
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What is Hydralazine
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Drug used in emergency heart failure
Arterial vasodilator decreases afterload can be combined with Nitroglycerin (venous vasodilator) |
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What is Isorbate dinitrate?
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drug used in emergency heart failure
venous dilator decrease preload |
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What are the intropes?
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Druge used in emergency cardiac failure
Dubutamine Dopamine Bipyridines -Amrinine -Milrinone |
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What is dubutamine?
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an inotrope used in emergency heart failure
1st line agent in heart disease and acts on Beta 1 receptors useful in cardiogenic shock due to decreased sympathetic tone, -decreased myocardial -contractility from toxins or inflammatory mediators Used when systolic function is poor - DCM not recommended for HCM (mare worsen diastolic function) increase mitral or tricuspid valvular regurgitation least likely of the cateholamines to cause arrhythmias may worsen the heart disease in the long term by increasing myocardial oxygen demand |
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What are the the Bipyridines?
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Milrinone (most potent)
Amrinone |
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What are mechanism of action of Bipyridines?
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they are phosphodiesterace inhibitors
- increase cAMP = cardiac contractility -increase Ca in cardiac Myocytes -increase cAMP in small muscle decreases calcium |
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What are the effects of Milrinone and amnrinone?
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phosphodiesterase inhibitors that increase contractility by increasing cAMP levels
work with heart disease associated with systolic function may cause arrhythmias and may worsen long term prognosis due to increase myocardiac work |
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What are drugs used in management of stable heart failure?
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loop diuretics
Thiazide diuretics Potassium sparing diuretics vasodilators -angiotensin converting enzyme inhibitors -angiotensin antagonists -Hydralozine |
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What beta blockers are used in the treatment of heart failure?
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Metoprolol
Carvediol Atenolol |
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What are examples of ACE inhibitors? effects?
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Enalapril
Lisinopril Bensepril Capropril vasodilation results in afterload reduction and may reduce preload in a colume overloaded heart decreases angiotensin II and bradykinin decreases aldosterone release used in congestive heart failure, glomerulonephritis, hypertension and chronic renal failure |
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What are adverse effects of ACE inhibitors?
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in renal disease there is a decrease in intraglomerular pressure resulting in decrease in GFR = azotemia
diuretics can cause idiosyncratic glomeruloar disease in cats (captopril) can cause GI irritation not recommended in patients win which decreased resistance does not improve heart function and worsens blood pressure |
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Whatus Hydralazine?
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a vasodilator that works on arteries and results in a decrease in afterload
|
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What is Losartan?
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angiotensin II antagonistv(competitive)
block agiotensin II formed by non ACE dependant pathways |
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What is Amlodipine?
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Ca channel blocker that causes arterial vasodilation resulting in discreased afterload
may be beneficial in heart disease based on some human studies but not clear |
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What are digitalis glycoside?
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positive inotropes such as
-Digoxin -Digitoxin -Ouabain |
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What are the effects of digitalis glycosides?
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contractility from Na/K ATPase in the myocardial cell membraine increases sodium available for exchanve with calcium
results in increased intracellular calcium which results in a positive inotropic effect kidney- improves GFR by increasing cardiac output -inhibition of renin release due to increased delivery of sodium to the distal tubule |
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What are the adverse effects of Digitalis Glycosides?
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don't treat it systolic function is normal - may worsen heart disease
Narrow safety margin and cats are often evaluated to if toxicity likely GI issues Bradyarrhythmias - parasympathetic tone tachyarrhythmias - intracellular Ca cardiac toxicity |
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What is Pimobendan?
|
Inodilator used to increase contractility
causes vasodilation by inbihiting inhibiting phosphodiesterase III sensitizes troponin C complex to intracellular Ca treatment of systolic failure beneficial in heart disease due to systolic failure (DCM) |
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How do beta blockers help in early heart failure?
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blunts the harmful effects of the sympatheitic nervous system and RAAS on the heart
may reverse cardiac remodeling and improve systolic function when given over a long period *dogs with DCM may not live long enough to see the benefit |
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What does Metoprolol and atenolol block?
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Beta 1 receptors
|
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What does Carvedilol block?
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Beta 1 and 2 and alpha 1
|
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What is an arrhythmia?
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cardiac disturbance in rate, rhythum or both
rate abnormalities -Bradycardia -Tachycardia Rhythm -regular -regularly irregular -irregularly irregular |
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What are causes of arrhythmias?
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disorders on conduction
disorders of impulse formation (pacemaker) |
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What are causes of conduction bradycardia?
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Block of SA node
-may not be seen if conducction is slow, see drop in P QRS or skipped beat -AV node may take over if complete Block of AV Node -1st degree porlonged beat or drop P QRS -2nd degree sometimes conduction is blocked 3rd degree - conduction is always blocked Blocked perkenji fibers -normal rate and regularity -change in ECG appearance |
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What are causes of condution tachycardia?
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due to premature excitation cells depolarizing the cell that deporlarize them
|
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What are the causes of impulse bradycardia?
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decrease in normal automaticity
decrease of discharge from autonomic SA node -parasympathetic stimulation -hyperkalemia -disease of node |
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What are the causes of impulse tachycardia?
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increased rate of firing from autonomic site
-increased sympathetic tone abnormal automaticity -cells normally autonomic are -cells normally slow are fast --myocardial ischeima --hypoxia - change in membrane portential abnormal early depolarization -increased sympathetic tone -electrolyte imbalance -drugs |
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What is sinus bradycardia?
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due to slowing of the SA node impulse formation
-increased vagal tone -sick sinus syndrome -drugs that change autonomic tone |
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What is a sinus arrhythmia?
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decrease in normal automaticity due to increase vagal tone during expiration
positive pressure during expiration increase BP there by activating baroreceptors |
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What is sinoatrial block?
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due to conduction clock in the SA node
may see skipped beats no P QRS seen Bradyarrhythmias |
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What is sinus arrest?
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due to cessation of sinus activity for more than two RR intervals
maybe due ti increase vagal tone or sinus node may see escape beats |
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What is atrial standstill?
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resembles sinus arrest due to depressed normal automaticity
causes include hyperkalemia, disease of the SA node no P wave may see QRS generated from other cells |
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What is an AV block?
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due to clock of conduction at AV node
may be due to increase vagal tone or decreased AV nide see P waves with no QRS can be 1st, 2nd, or 3rd degree |
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What are the cause of tachyarrhythmias?
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due to enhanced normal automaticity
often via increased sympathetic tone |
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What is a supracentricular premature depolarization?
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originates in the AV node
often due to re-entry, abnormal automaticity or triggered activity |
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What is Preexcitation syndrome?
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due to abnormal communication between the atria and ventricles that can cause reentry
|
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What is Atrial flutter?
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often due to reentry loops
no P waves see F waves |
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What is atrial fibrillation?
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often due to multiple re-entry loops
irregularly irregular rhythm no P waves |
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What is ventricular fibrillation?
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impulse originates form ventricle
due to multiple re entry loops will see no PQRS just undulating base line |
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What are treatment considerations when treating arrythmias?
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antiarrhythmias change action potential and conduction of impulse
change may convert a rhythm -re-entry -tissue may be refractory when loop comes around May offer rate control by decrease conduction -decrease AV conduction in atrial fibrillation may arrythmias so not need to treated with antiarrhythmics -side effects out weigh benefits -idoventricular rhythm -sinus tachycardia sometimes can obtain rate control in dogs with DCM |
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What are the class IA drugs?
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drugs used to treat tachyarrhythmias by blocking sodium blockers
-prolong action potential Quinidine Procainamide |
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What are the class IB drugs?
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Drugs used to treat tachyarrhythmias
sodium channel blockers shortens action potential -lidocaine -phenytoin -Mexieltine |
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What are the class II drugs?
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Beta blockers
-propranolol -timolol -pindolol -Atenolol -Asmolol -Metoprolol -carevedilol |
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What are the class III drugs?
|
Bretylium
Amiodarone Sotalol K channel blockers |
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What are class IV drugs?
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Verapamil
Diltiazem |
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What is the treatment of supracentriular arrhytmias?
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drugs that decrease rate or decrease arrythmias
-Digoxin -Beta Blocker -Calcium Channel Blocker |
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What is the treatment of atrial tachycardia, atrial flutter and atrial fibrillation?
|
Diltiazem (class IV)
Digixin Beta Blockers (class II) Quindine and procainamide can be tried it other drugs are ineffective in emergency or chronic therapy |
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What is the treatment of ventricular prematire complexes?
|
often do not require treatment or at least not emergency treatment
|
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What can you use to treat ventricular tachycardia in an emergency setting?
|
Lidocaine
Procainamide if lidocaine doesn't work beta blockers Amiodarone if lidocaine doesn't work |
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How do you treat tachyarrhythmias in cats?
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betablockers
cats are sensitive to lidocaine- do not use systemically |
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What is Procainamide?
|
a class Ia drug
sodium channel blocker prolongs the action potential -decrease velocity -decrease automaticity -decrease myocardial excitability Prokinetic |
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What is Quinidine?
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drug of choice for atrial fibrillation in the horse
class Ia sodium channel blocker -prolongs the action potential |
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What is lidocaine?
|
local anesthetic that is the drug of choice for life threatening ventricular arrhythmias in dogs
class IB sodium channel blocker Shortens action potential increases motility in horses do not use in cats systemically |
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What is Phenytoin?
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used to help tachycarrhythmias caused by digitalis glycosides in dogs
used for seizure prevention class II with an action similar to lidocaine |
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What is Mexiletine?
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similar to lidocaine but given orally
used for ventricular arrhythmias |
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What flecainide?
|
a drug that blocks sodium channels
does not effect action proteinal ot refractory results in the strongest repression at the O phase -decrease impulse conduction -suppression of cardiac contractility can be antiarrhythmiac or proarrythmic |
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What are arrhythmias are beta blockers used for in cats?
|
Supracetricular and ventricular arrhythmias
|
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What are examples of non selective beta blockers?
|
Propranolol
Timolol Pindolol -used for supraventricular arrythmias -anesthesmia induced, digitalis induced arrythimias -glaucoma -hypertension -hyoperthyrodism |
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What are adverse effects of beta blockers?
|
Sinus bradycardia
and decrease contractility tachycardia because of sudden withdrawal -hypoglycemia -Bronchospasm -hyperkalemia -GI side effects -sedation -seizures at toxic doses |
|
What are selective beta 1 blockers?
|
Metoprolol, Esmolol, Atenolol
used in patients with asthma, diabetes and peripheral vascular disease -no beta 2 blockade Atenolol is used in cats to reduce heart rate in heart disease |
|
What is sotolol?
|
a drug that acts as a non selective class II drug at low doses
acts as a class III drug at high doses (K channel blocker) often used for ventricular arrythmias |
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What drugs are Ca channel blockers?
|
Diltiazem (anti arrhythmic)
Verapamil (anti arrhythmic) used for supraventricular arrhythmias inhibits slow inward Ca during action potential resulting in decreased intracellular calcium -control supraventricular arrhythmias -interrupt arrhythmias triggered by automaticity -slows subus rate, negative inotropes, decrease AV conduction |
|
What is the treatment for cardiac asystole?
|
epinephrine
vasopressin |
|
What is the cause of hypertension in animals?
|
usually secondary due to:
-renal disease -daibetes -hyperthyroid -Pheochromocytoma |
|
Drugs used in the treatment of hypertension work by what mechanism?
|
vasodilation
decrease cardiac contractility and rate decrease blood volume use vasodilators beta blockers |