急性心衰和心源性休克.ppt

1、 Acute Heart Failure/Cardiogenic ShockApril 16,2004Darren M.Triller,PharmDThe planStick close to the textReview pharmacology and pathophysiology only to enhance understanding of the drug therapyKnow the few drugs wellExpectations for pharmacists in general hospital or home care practiceTest question

2、s will target these goalsWhy is this important?HF common diagnosisHospitalizations are commonAssociated costs are astronomicalPharmacists will routinely be involved in preparing and dispensing to ICU/CCUUse of the drugs is frequently in urgent/emergent situationsAcute HF/Cardiogenic shockDeathShockI

3、II Heart FailureIIIIVHTNDrugsMIValve DzMIRelationships/Key TermsCardiac output=HR x Stroke volumeMAP=CO x SVRPreloadContractilityAfterloadFrank-Starling relationshipThe Big Picture in FailurePreloadContractilityNeed volume to increase stretch,Frank StarlingNeed contractility and rate to maintain out

4、putNeed constriction to maintain pressureAfterloadVeinsHeartArteriesAutoregulationThe ability to maintain blood flow over wide range of perfusion pressuresCerebral and coronary arteriesAbility declines at MAP 60mmHgMediated byvasoconstrictors:epi,NE,AngII,TxA2,vasopressinvasodilators:PGI2,NO,adenosi

5、ne,natriuretic peptidesNormal reflex mechanismsIncrease preload:Na/H20 retention,RAASIncreased contractility:adrenergic outflow(NE)Increased afterload:norepi,AngII,endothelin,vasopressinIt is important to relax!Remember that coronary arteries fill during diastoleRemember that filling during diastole

6、 contributes to stroke volume(Starling)Remember that increasing heart rate decreases ventricular and coronary filling,upsets calcium processing by SR,O2 demand increaseChronic HF patients have typically maxed out preload,and do not have the reserve that you do ContractilityIncreased contractility wi

7、ll provide increased stroke volume/CO for a given level of preload and afterloadChronic HF patients have high circulating levels of catecholamines and are less responsive to adrenergic stimulireceptor downregulationCatecholamines cardiotoxic?Necrosis/apoptosis?Arrhythmias?Afterload is double edged s

8、wordIncreased SVR is important for maintaining MAPIncreased afterload will reduce stroke volumeslams the screen door before all the kids get outChronic HF patients are very succeptable to increases in afterloadApproach to patientAssess status:s/s,target organ damageAddress alterable causesDrugsDisea

9、ses/conditionsAssess fluid status-over or under hydrated?Assess severity and initiate pharmacotherapyAdjust moment by momentPatient monitoringVital signsAcid/baseOxygenationHydrationRenal functionSwan linePCWPCardiac outputApproach by hemodynamic subsetPCWPCISTD treatment/monitoringMortality increas

10、es from set to set!See figure 13-7 in text.Subset OnePatient symptomaticWarrant full work-upAddress other causeMaximize oral therapy for chronic HFACEIBBDiureticsDigMisc.:vaccines,smoking cessation,diet,education,etc.Approach by hemodynamic subsetPCWPCILower pcwp(preload)with nitrates,diureticsMorta

11、lity increases from set to set!See figure 13-7 in text.Subset TwoPatient perfusing at expense of higher pressureGradually lower PAOP without causing adverse effectsAvoid over-shooting or else!Avoid prompting reflex mechanismsTypically involves diuretics,nitrates and(more recently)nesiritide.Nitrogly

12、cerinePreferred preload reducerDecreases PCWP,decreases pulmonary congestionCheap,short T50,easily titratedUsed in combination with inotropes in patients with pulmonary congestion and reduced LV functionCoronary dilation at high doses:useful in patients with ischemiaAvoid if elevated intracranial pr

13、essureTolerance in 12-72 hoursTypical Dosage/AdministrationProtect from lightStable in D5W or NS in GLASS or special containerSpecial“nitro”tubing,avoid filtersCheck for infusion incompatabilities5 to 10mcg/min initiallyTitrate up to about 200mcg/min as continuous IV infusionDiureticsVasodilation:5-

14、10min,prostaglandin mediatedDiuresis:20+minutesReduction in preload in patients with volume depletion or decreased diastolic function may be harmfulDoes not improve CI/CO in most patients(curve flat)Role:use carefully to reduce symptoms of congestion without compromising cardiac outputLoop diuretics

15、Furosemide(Lasix)IV(40mg/5ml),IM,POBioavailability poor/variableStable in LR,D5W or LRTypically 40mg 80mg IVP over 1-2 minRepeat every 1-2 hours as neededMonitor hemodynamicsMonitor I/O for measure of net fluid lossAdminister potassium as needed in fluidsOtotoxicity,allergy possibleOther DiureticsBu

16、metanide(Bumex):1/40th dose of lasixGood bioavailabilityIV,IM,PO0.5-1mg IVP over 1-2 minutes,repeat 1-2 hrs0.25mg/ml solution;0.5mg,1mg,2mg tabletLasix refractory or allergic patientsCan cause musculoskeletal s/sTorsemide(Demadex)IV/PODose approximately half of lasix doseGood bioavailabilityPotential PK and electrolyte advantages over furosemideDiuretic resistanceAfterload reduction“Renal dose”dopamineIncrease bolus doseContinuous infusionAdd thiazideDiuril(chlorothiazide)Continuous InfusionsBum