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Download Cardiac Meds Cardiac Output Stroke VolumeHeart Rate Meds Sympathetic Stimulation AfterloadPreload Contractility X = PVR Viscosity Aortic Impedance Venous

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Cardiac Meds

Cardiac MedsCardiac OutputStroke VolumeHeart RateMedsSympathetic StimulationAfterloadPreloadContractilityX=PVRViscosityAortic ImpedanceVenous ReturnVentricularCompliance1PreloadFunction of the volume of blood to the LV and the compliance (ability of the ventricle to stretch) of the ventricles at the end of diastole (LVEDP)Factors affecting are: venous return, total blood volume and atrial kickHypovolemic patient has too little preloadHeart failure patient has too much preload

2AfterloadVentricular wall tension or stress during systolic ejectionIncrease in afterload relates to an increase in the work of the heartIncreased afterload R/T:Aortic stenosisVasoconstriction and SVRBlood volume and viscosityTo decrease, use vasodilators, decrease myocardial oxygen demand

3ContractilityInotrophy or enhancing strength, can be positive or negativeSympathetic medications increase contractilityCa++ is a medication that will increase contractility by increasing actin and myosin contractionsDigoxin also works to increase Ca++ channels by slowing the Na/Ca pump

4Control of Heart RateSNS- sympathetic nervous systemFight or flightIncrease HR, BP, respirations, dilate pupilsPNS- parasympathetic systemDecreases contractility, rateVagus nerves to the SA and AV nodesBaroreceptors- pressure sensors in carotids and aortic archesChemoreceptors- pH levels in aortic archANF- atrial natriuretic factor- hormone secreted by the atria in response to atrial pressureCauses Na and water to be excreted and also vasodilates5Control of Stroke VolumePreloadIncrease use:Fluid resusitationDecrease use:Diuretics and vasodilatorsAfterloadIncrease use:VasopressorsVolume expandersAfterloadDecrease use:VasodilatorsDiureticsDecrease sympathetic stimulationContractilityIncrease use:Sympathetic stimulantsDecrease use:CCBsDecrease sympathetics

6VasopressorsSympathomimetic-inotrophicMedications that mimic the sympathetic system, work on alpha, beta and dopamineric receptorsRequire continuous monitoring of BP and heart rateAlpha: vasoconstricts peripheral arteriolesBeta 1: Increased HR, contractilityBeta 2: Bronchodilation

7VasopressorDopamine Stimulates alpha and beta receptorsIn small doses (2-5 mcg/kg/min) produces renal vasodilationLarger doses (max 20 mcg/kg/min) alpha and beta stimulationIncreases HR and BPPrecautions:Give IV only, can sloughing of tissue with extravasation, if it does infiltrate, give phentolamine IV to the siteTachyarrhythmias, palpations, hypotension if not hydrated, headache, dyspnea8VasopressorEpinephrineAlpha-Adrenergic, beta 1 and beta 2 stimulantProduces bronchodilation and vasoconstrictionIncreases HR, BP and bronchodilatesGiven IV, SQ and inhalationMax is 20 mcg/minPrecautions:TachyarrhythmiasAnginaNervousness, tremorsHypertensionWorks almost immediately IVWatch for chest pain and HR >120, can cause cardiac arrest with too last a rate9VasopressorNorepinephrineStimulates alpha, beta receptorsNeed to hydrate patientLacks beta 2 effectsMarked alpha vasoconstrictionUsed in shock statesMax is 16 mcg/minPrecautions:Closely monitor HR and BP, can elevate quicklyMonitor for peripheral vasoconstriction, in high doses, can constrict all extremitiesCan decrease the C.O. if rate is too high10VasopressorDobutamineSynthetic cathecholamine with mainly beta effectsMild stimulation of beta 2Increases myocardial contractilityUseful with heart failure patientsMax is 20 mcg/kg/minPrecautions:Monitor for increased HR and BPPVCs and anginaWatch for shortness of breathMay be given over a long infusion for heart failure patients

11Vasopressors- Phosphodiesterase InhibitorsCause increased levels of AMP and Ca++Medications:Amrinone (Inocor)Milrinone (Primacor)Cause an increase in cardiac output and some decreased afterloadEffective in heart failure patients to increase C.O.Precautions:Given as a continuous IV infusionCan cause PVCs and V tach because of increased contractionMonitor for drops in BP R/T decreased afterloadWatch for thrombocytopenia and abnormal liver function12Other VasopressorsPhenylephrine (neo-synephrine)Stimulates alpha receptors onlyUsed by anesthesiaCan increase myocardial demandWorks very quicklyVasopressin (antidiuretic hormone)Nonadrenergic peripheral vasoconstrictorUsed in VF and pulseless VT, 40UnitsUsed as an IV infusion in sepsis with peripheral vasodilation

13Vasodilators- Direct Smooth Muscle RelaxantsDecrease PVRArterial and venous dilationImproves cardiac outputMedications:Nitroprusside (Nipride)NitroglycerideHydralazine (Apresoline)Precautions:Closely monitor BP, can drop dramatically, especially niprideLong term nitroprusside therapy can lead to thiocyanate toxicityNTG is used with unstable angina (given 5-300 mcg/minApresoline is not a continuous infusion, major side effect is tachycardia14Vasodilators- Ca++ Channel BlockersArterial vasodilationReduce the influx of calcium and decrease resistanceUsed mostly for hypertensionAlso to slow rapid rhythms, such as SVT, and Atrial fibMedications:Nicardipine (Cardene)Nifedipine (Procardia)Diltiazem (Cardizem)Verapamil (Calan)Side effects:Hypotension, bradycardia, nausea, heart failure and peripheral edema

15Vasodilators-ACE inhibitorsVasodilate by blocking the conversion of angiotensin I to angiotensin II, decreases PVRMay drop BP dramatically if volume depletedStops Na and water retentionMedications:Captopril (Capoten)Enalapril (Vasotec)Precautions:Hypotension, chronic cough, neutropenia and elevated liver enzymes16Vasodilators- Alpha adrenergic blockersBlock peripheral alpha receptors in arteries and veinsOrthostatic changes may resultMay lead to fluid retentionMedications:Labetalol (normadyne)Alpha & beta blockerDecreased BP without increased HRUsed in aortic dissectionsPhentolamine (Regitine)Peripheral alpha blocker, decreases afterloadUsed with pheochromocytomas17Vasodilators- DA-1 receptor agonists & Synthetic BNPDopamine DA-1 receptor agonists, vasodilates peripheral and renal arteriesMedication:Fenoldopam (Corlapam)Hypertensive emergenciesWatch for hypotension and tachycardiaNatrecor:Brain naturietic peptideUsed for decompensated HR with dyspneaVasodilates pulmonary bed, reduces SVR and PVRLowers BNP levelsInfusion runs for 6-48 hours18Vaughn Williams Classification- Used for AntiarrhythmicsClass I agents interfere with the sodium (Na+) channel. Class II agents are anti-sympathetic nervous system agents. Most agents in this class are beta blockers. Class III agents affect potassium (K+) efflux. Class IV agents affect calcium channels and the AV node. Class V agents work by other or unknown mechanisms. 19[edit] Class I agents

Class IaMedications:QuinidineProcainamideDisopyramide

Type:Na+ channel block intermediateUse:Ventricular arrhythmiasPrevents recurrent atrial fib, triggered by overactive vagal stimulation (Wolff-Parkinson-White syndrome)20Class IbMedication:LidocainePhenytoinMexiletine

Type:Na+ channel block fastUse:Ventricular tachycardiaAtrial fibPrevention during and immediately after an MI, but it is now discouraged R/T increased risk of asystole

21Class IcMedications:FlecainidePropafenoneMoricizine

Type:Na+ channel block slowUse:Prevents paroxysmal atrial fibTreats recurrent tachyarrhythmias of abnormal conduction system22Class IIMedications:PropranololEsmololTimololMetoprololAtenololType:Beta BlockerUse:Decrease myocardial infarction mortality, used post MIPrevent recurrence of tachyarrhythmiasDecrease Beta 1 and 2 stimulation, decrease HR and BPSide effects of bradycardia, fatigue, wt. gain, impotence, depression

23Class IIIMedications:AmiodaroneSotalol (also a Beta)IbutilideDofetilide

Type:K+ channel blockerUse:Ventricular tachyarrhythmiasAtrial flutter and atrial fibWolff-Parkinson-White syndromeSide effects:SOB, bronchospasm, renal or hepatic insufficiencyPhotosensitive, use sunscreen and sunglasses, may cause bluing of periphery

24Class IVMedications:VerapamilDiltiazem

Type:Ca++ channel blockerUse:Prevent recurrence of paroxysmal SVTReduce ventricular rate in patients with atrial fibDecrease the contraction of muscle tissue, prevents slide of actin and myosinAvoid grapefruit juice it can increase serum levels, as do high fat mealsMonitor thyroid function

25Class VMedications:AdenosineDigoxin

Type:Work by other methods, direct nodal inhibitionNa/Ca pumpUse:Supraventricular arrhythmias Contraindicated in ventricular arrhythmiasSide effects:Digoxin- bradycardia, anorexia, nausea & vomiting, yellow/green halos, heart blocks, arrhythmias, causes hypocalcemia and hypokalemia

26AspirinActs to reduce inflammation by inhibiting the production of prostaglandinsDecreases platelet aggregation, decreases the incidence of TIAs and MIDosage of 81 mg maintenance, not enteric coated in MIMonitor for GI bleeding, exfoliative dermatitis, Stevens-Johnson syndrome, tinnitus

27Other Emergency MedicationsAtropine:Parasympathicolytic, enhances the SA node and AV node conductionUsed for bradycardia and asystoleSide effects:Tachycardia, urinary retention, blurred vision, bowel obstruction, not for Complete heart blockCalcium Cl:Enhances myocardial contractility for pts with elevated K, Mg and low Ca and CCB toxicitySide effects:Coronary and cerebral vasospasm, ventricular irritability, cautious if on DigoxinOther Emergency MedicationsMagnesiumReduces post infarction arrhythmias and pump failureHypomagnesemia can cause refractory V fib and sudden cardiac deathSide effects:Flushing, sweating, hypotension, sensation of heat, flaccid paralysis, circulatory collapseDiprivan (Propofol)Short acting sedative, used for sedation with patients who have airway and ventilatory supportSide effects:Hypotension, rebound tachycardia and increased ICP when wean off, hepatotoxicityOther Emergency MedicationsLorazepam (Ativan)Benzodiazepine sedativeEffects last 6-8 hoursIf given intraarterial c

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