CVS常用药物概论-精选文档.ppt

分類,Inotropes: 強心 Chronotropic: 增快心律 Pressors: 升壓 Vasodilator: 降壓 Antiarrhytmic agents:抗心律不整,常用藥物,Bosmine (Epinephrine) Levophed (Norepinephrine) Dopamine Dobutamine Primacor (Milrinone) Isuprel NTG Nitroglyceride Perdipine Amiodarone PGE1 DDAVP,Cardiovascular Anatomy,CONTRACTILITY,HEART RATE Rhythm,PRELOAD,AFTERLOAD,L/Min,CARDIAC OUTPUT (CI=CO/m²),Catecholamines,Natural Norepinephrine: a , b1 Epinephrine: a, b Dopamine: D, a1, b1 (also some NE release) Synthetic Isoproterenol: b Dobutamine: b1 (and mix of b2 stimulation and a1 inhibition and stimulation),NE E ISO,g/kg/min,160 mg in 100 ml, 50 kg (mg/ml) 160*1000 : mg/ml g/ml 160 * 1000/100 : 100ml 1ml 160 *1000/100/60 : g/h g/min 160/6/50 = 0.533 g/kg/min,Thanks for your attention! Have a nice weekend!,Thanks for your attention! Have a nice weekend!,Thanks for your attention! Have a nice weekend!,ALPHA-ADRENERGIC MEDICATIONS,Can be divided into: Alpha1-adrenergic effects: Vascular smooth muscle contraction Alpha2-adrenergic effects: Vascular smooth muscle relaxation-this is a very mild effect only at low doses of an alpha-adrenergic agent like epinephrine.,BETA-ADRENERGIC MEDICATIONS,Can be divided into: Beta1-adrenergic effects: Direct cardiac effects Inotropy (improved cardiac contractility) Chronotropy (increased heart rate) Beta2-adrenergic effects: Vasodilation Bronchodilation,Epinephrine,1 contractility and H.R C.O. and myocardial oxygen demand. 1 splanchnic and renal blood flow butcoronary and cerebral perfusion pressure, SBP 2 vasodilation in skeletal muscle may lower diastolic pressure also relaxes bronchial smooth muscle,Dopamine vs Dobutamine,Selecting inotropic and vasopressor agents for specific hemodynamic disturbances in children,Hemodynamic pattern,Normal,Deceased,Elevated,Blood pressure or SVR,Myocardial dysfunction,Dobutamine or dopamine or amrinone,Epinephrine or dopamine (or dobutamine plus norepinephrine),Dobutamine plus nitroprusside,CHF,Dobutamine Primacor,Dopamine,Dobutamine plus nitroprusside,Bradycardia,None,Isoproterenol,None,Dobutamine Indications,Consider for pump problems (CHF) with systolic blood pressure of 70 to 100 mm Hg and no signs of shock,Dobutamine Precautions,Avoid with systolic blood pressure 100 mm Hg and signs of shock May cause tachyarrhythmias, fluctuations in blood pressure, headache, and nausea Contraindication: Suspected or known poison/drug-induced shock Do not mix with sodium bicarbonate.,Dobutamine IV Infusion,Usual infusion rate: 2 to 20 µg/kg /min Titrate so heart rate does not increase by 10% of baseline Hemodynamic monitoring is recommended for optimal use,Dopamine Indications,2nd drug for symptomatic bradycardia after atropine Use for hypotension (systolic blood pressure = 70 - 100 mm Hg) with signs and symptoms of shock,Dopamine Precautions,May use in patients with hypovolemia but only after volume replacement Use with caution in cardiogenic shock with accompanying congestive heart failure May cause tachyarrhythmias, excessive vasoconstriction Taper slowly. Do not mix with sodium bicarbonate,Dopamine Continuous Infusions,Titrate to patient response: Low Dose 1 to 5 µg/kg per minute (“renal doses) Moderate Dose 5 to 10 µg/kg per minute (“cardiac doses”) High Dose 10 to 20 µg/kg per minute (“pressor doses”),Epinephrine Indications,Cardiac arrest: VF, pulseless VT, asystole, PEA Symptomatic bradycardia: After atropine, dopamine and TCP Severe hypotension, Anaphylaxis: Combine with large fluid volumes, corticosteroids, antihistamines,Epinephrine Precautions,Raising BP and increasing HR may cause myocardial ischemia, angina High doses do not improve survival or neurologic outcome and may contribute to postresuscitation myocardial dysfunction Higher doses may be required to treat poison/drug-induced shock,Epinephrine in Cardiac Arrest,IV Dose: 1 mg (10 mL of 1:10 000 solution) administered every 3 to 5 minutes during resuscitation Follow each dose with 20 mL IV flush. ETT: 2 to 2.5 mg (1:1000) diluted in 10 mL normal saline.,Isoproterenol Indications,Use cautiously as temporizing measure if external pacer is not available for treatment of symptomatic bradycardia Refractory torsades unresponsive to MgSO4 Temporary control of bradycardia in heart transplant patients Poisoning from ß-adrenergic blockers,Isoproterenol Precautions,Do not use for treatment of cardiac arrest Increases myocardial oxygen requirements Do not give with epinephrine; can cause VF/VT Do not administer with poison/drug induced shock (exception: ß-blocker poisoning) Higher doses are Class III (harmful) except for ß-adrenergic blocker poisoning,Isoproterenol IV Infusion,Infuse at 2 to 10 µg/min Titrate to adequate heart rate In torsades, titrate to increase heart rate until VT is suppressed,Lidocaine Indications,Cardiac arrest from VF/VT Stable VT, wide-complex tachycardias of uncertain type, wide-complex PSVT (Class Indeterminate),Lidocaine Precautions,Prophylactic use in AMI patients is not recommended Reduce maintenance dose (not loading dose) in presence of impaired liver function or left ventricular dysfunction Discontinue infusion immediately if signs of toxicity develop,Lidocaine in Cardiac Arrest From VF/VT,Initial dose: 1 to 1.5 mg/kg IV For refractory VF may give additional 0.5 to 0.75 mg/kg IV push, repeat in 5 to 10 minutes; maximum total dose: 3 mg/kg. ETT: 2 to 4 mg/kg.,Lidocaine,Perfusing Arrhythmia For stable VT, wide-complex tachycardia of uncertain type, significant ectopy: 1 to 1.5 mg/kg IVP Repeat 0.5 to 0.75 mg/kg every 5 to 10 minutes Maximum total dose: 3 mg/kg. Maintenance Infusion 2 to 4 mg/min,Magnesium Sulfate Indications,Cardiac arrest only if torsades de pointes or suspected hypomagnesemia is present Refractory VF (after lidocaine) Torsades de pointes with a pulse Life-threatening ventricular arrhythmias due to digitalis toxicity,Magnesium Sulfate Precautions,Occasional fall in blood pressure with rapid administration. Use with caution if renal failure is present.,Magnesium Sulfate Administration,Cardiac Arrest (for hypomagnesemia or TdP) 1 to 2 g (2 to 4 mL of a 50% solution) diluted in 10 mL of D5W IVP Torsades de Pointes (not in cardiac arrest) Loading dose of 1 to 2 g mixed in 50 to 100 mL of D5W, over 5 to 60 minutes IV Follow with 0.5 to 1 g/h IV (titrate dose to control the torsades),Nitroglycerin Indications,Initial antianginal for suspected ischemic pain For initial 24 to 48 hours in patients with AMI and CHF, large anterior wall infarction, persistent or recurrent ischemia, or hypertension Continued use (beyond 48 hours) for patients with recurrent angina or persistent pulmonary congestion Hypertensive urgency with ACS,Nitroglycerin Precautions/Contraindications,Limit normotensive BP drop to 10% Limit hypertensive BP drop to 30% Avoid BP drop below 90 mm Hg Do not mix with other drugs Sit or lie pt down when receiving med Do not shake aerosol spray (affects metered dose) Contraindications Hypotension Severe bradycardia or severe tachycardia RV infarction Viagra within 24 hours,Nitroglycerin Administration,IV Bolus/Infusion IV bolus: 12.5 to 25 µg Infuse at 10 to 20 µg/min Route of choice for emergencies Titrate to effect Sublingual Route 1 tablet (0.3 to 0.4 mg); repeat every 5 minutes. Aerosol Spray Spray for 0.5 to 1 second at 5-minute intervals (provides 0.4 mg per dose).,Nitroprusside Indications,Hypertensive crisis. To reduce afterload in heart failure and acute pulmonary edema To reduce afterload in acute mitral or aortic valve regurgitation,Nitroprusside Precautions,Light-sensitive; therefore, wrap drug reservoir in aluminum foil May cause hypotension, thiocyanate toxicity, and CO2 retention. May reverse hypoxic pulmonary vasoconstriction in patients with pulmonary disease, exacerbating intrapulmonary shunting, resulting in hypoxemia Other side effects include headaches, nausea, vomiting, and abdominal cramps,Nitroprusside IV Infusion,Begin at 0.1 µg/kg per minute and titrate upward every 3 to 5 minutes to desired effect (up to 5 µg/kg per minute). Use with an infusion pump Action occurs within 1 to 2 minutes,Norepinephrine Indications,For severe cardiogenic shock and hemodynamically significant hypotension (BP70 mm Hg) with low total peripheral resistance This is an agent of last resort for management of ischemic heart disease and shock,Norepinephrine Precautions,Increases myocardial oxygen requirements because it raises blood pressure and heart rate May induce arrhythmias. Use with caution in patients with acute ischemia; monitor cardiac output Extravasation causes tissue necrosis If extravasation occurs, administer phentolamine 5 to 10 mg in 10 to 15 mL NS, infiltrated into area,Norepinephrine IV Infusion,0.5 to 1 µg/min titrated to improve BP (up to 30 µg/min) Do not administer in same IV line as alkaline solutions Poison/drug-induced hypotension may require higher doses to achieve adequate perfusion,Cardiac Physiology,Nervous Control of the Heart Sympathetic Parasympathetic Autonomic Control of the Heart Chronotropy Inotropy Dromotropy Role of Electrolytes,Catecholamines,Natural Norepinephrine: a , b1 Epinephrine: a, b Dopamine: D, a1, b1 (also some NE release) Synthetic Isoproterenol: b Dobutamine: b1 (and mix of b2 stimulation and a1 inhibition and stimulation),Noncatecholamines,Direct-acting Albuterol: b2 Clonidine: a2 Phenylephrine: a1 Mixed-acting Ephedrine: a (CNS), b, and NE release Indirect-acting (effects from NE release) Tyramine: a , b1 Amphetamine: a (CNS), b1 (also DA and 5-HT release centrally),Therapeutic uses (2),Cardiac stimulation (b1, b2) In bradycardia: dopamine, epinephrine In hypotension: dopamine, norepinephrine In normotension: dobutamine Bronchial dilation (b2) In bronchial asthma: albuterol In anaphylaxis: epinephrine Ocular effects Pupillary dilation (a1): phenylephrine Glaucoma (a2): epinephrine,CARDIOVASCULAR MEDICATIONS,Main actions of most of the following cardiovascular medications will be determined by the adrenergic effects of the medications. Can either be: alpha-adrenergic beta-adrenergic dopaminergic,CARDIAC MEDS VIA CONTINUOUS INFUSION,Epinephrine Norepinephrine Dopamine Dobutamine Milrinone/Amrinone Sodium Nitroprusside Nitroglycerin Isoproterenol,EPINEPHRINE,Both an alpha- and beta-adrenergic agent Therefore, indications for its use as a continuous infusion are: low cardiac output state beta effects will improve cardiac function alpha effects may increase afterload and decrease cardiac output septic shock useful for both inotropy and vasoconstriction,EPINEPHRINE,Actions are dose dependent (mcg/kg/min): 0.02-0.08 = mostly beta1 and beta2 stimulation. increased cardiac output mild vasodilation 0.1-2.0 = mix of beta1 and alpha1 increase cardiac output increase SVR = vasoconstriction 2.0 = mostly alpha1 increase SVR, and may decrease CO by increasing afterload,EPINEPHRINE,Side effects include: Anxiety, tremors,palpitations Tachycardia and tachyarrhythmias Increased myocardial oxygen requirements and potential to cause ischemia Decreased splanchnic and hepatic circulation (elevation of AST and ALT) Anti-Insulin effects: lactic acidosis, hyperglycemia,NOREPINEPHRINE,Employed primarily for its alpha agonist effect - increases SVR (and B.P.) without significantly increasing C.O. Used in cases of low SVR and hypotension such as profound “warm shock” with a normal or high C.O. state Infusion rates titrated between 0.05 to 1 mcg/kg/min,NOREPINEPHRINE,In general, norepinephrine differs from epinephrine in that at doses used in clinical practice, the vasoconstriction outweighs any increase in cardiac output. i.e. norepinephrine usually increases blood pressure and SVR, often without increasing cardiac output.,NOREPINEPHRINE,Side Effects: Similar to those of Epinephrine Can compromise perfusion in extremities and may need to be combined with a vasodilator e.g. Dobutamine or Nipride More profound effect on sphlancnic circulation and myocardial oxygen consumption,DOPAMINE,Intermediate product in the enzymatic pathway leading to the production of norepinephrine; thus, it indirectly acts by releasing norepinephrine. Directly has alpha, beta and dopaminergic actions which are dose-dependent. Indications are based on the adrenergic actions desired.,DOPAMINE,Improve renal perfusion 2-5 mcg/kg/min Improve C.O. in mild to moderate Cardiogenic or Distributive Shock 5-10mcg/kg/min Post-resuscitation stabilization in patients with hypotension (in conjuction with fluid therapy) 10-20mcg/kg/min,DOBUTAMINE,Synthetic catecholamine with inotropic effect (increases stroke volume) and peripheral vasodilation (decreases afterload) Positive chronotropic effect (increases HR) Some lusotropic effect Overall, improves Cardiac Output by above beta-agonist acitivity,DOBUTAMINE,Major metabolite is 3-O-methyldobutamine, a potent inhibitor of alpha-adrenoceptors. Therefore, vasodilation is possible secondary to this metabolite. Usual starting infusion rate is 5 mcg/kg/min, with the dose being titrated to effect up to 20 mcg/kg/min.,DOBUTAMINE,Used in low C.O. states and CHF e.g. myocarditis, cardiomyopathy, myocardial infarction If BP adequate, can be combined with afterload reducer (Nipride or ACE inhibitor) In combination with Epi/Norepi in profound shock states to improve Cardiac Output and provide some peripheral vasodilatation,MILRINONE/AMRINONE,Belong to new class of agents “Bipyridines” Non-receptor mediated activity based on selective inhibition of Phosphodiesterase Type III enzyme resulting in cAMP accumulation in myocardium cAMP increases force of contraction and rate and extent of relaxation of myocardium Inotropic, vasodilator and lusotropic effect,AMRINONE,First generation agent - limited use now Long half-life (4.4 hours) with potential for prolonged hypotension after loading dose Associated with thrombocytopenia Dosage: Load with 0.75 mg/kg with infusion rate of 5-10 mcg/kg/min Milrinone is preferred drug from this group,MILRINONE,Increases CO by improving contractility, decreased SVR, PVR (?), lusotropic effect; decreased preload due to vasodilatation Unique in beneficial effects on RV function Half-life is 1-2 hours Load with 50 mcg/kg over 30 mins followed by 0.3 to 0.75 mcg/kg/min No increase in myocardial O2 requirement,VASODILATORS,Classified by site of action Venodilators: reduce preload - Nitroglycerin Arteriolar dilators: reduce afterload Minoxidil and Hydralazine Combined: act on both arterial and venous beds and reduce both pre- and afterload Sodium Nitroprusside (Nipride),NITROPRUSSIDE,Vasodilator that acts directly on arterial and venous vascular smooth muscle. Indicated in hypertension and low cardiac output states with increased SVR. Also used in post-operative cardiac surgery to decrease afterload on an injured heart. Action is immediate; half-life is short; titratable action.,NITROPRUSSIDE,Toxicity is with cyanide, one of the metabolite