CARDIAC ANESTHESIAPART IIIDENNIS STEVENS CRNA, MSN, ARNPJULY 2006FLORIDA INTERNATIONAL UNIVERSITYPRINCIPLES OF ANESTHESIOLOGY NURSING IIINGR 6094

CARDIAC ANESTHESIAOBJECTIVESDiscuss location of cardiac valves in relation to structures of the heart.Explain the physiologic function of cardiac valves within the cardiac circulatory system.State pertinent factors that should be evaluated in the preoperative period for patients with valvular heart disease.Discuss anesthetic considerations related to valvular repair or replacement surgical procedures.Explain weaning criteria from cardiopulmonary bypass.

CARDIAC ANESTHESIACARDIAC SKELETONTough fibrous rings surround the AV valves and act as points of attachmentTwo additional fibrous annuli develop in relation to the bases of the aorta and the pulmonary trunkAnnulus fibrosis is the fixation point for cardiac musculature and plays an important role in the structure, function, and efficiency of the heart

CARDIAC ANESTHESIACHAMBERS OF THE HEARTThe atria are smaller and thinner walled than the ventriclesVentricles have a thicker myocardial layer and make up much of the bulk of the heartAtria are storage units and conduits for blood that is emptied into the ventriclesVentricles must propel blood through pulmonary or systemic circulation

CARDIAC ANESTHESIARIGHT ATRIUMRA serves as a reservoir for the RVMuscle wall thickness of ~2 mmRA receives blood from SVC, IVC, and coronary sinusRA consists of two parts:Anterior, thin-walled trabeculated portionPosterior, smooth-walled portionInteratrial septumFossa ovalis cordis

CARDIAC ANESTHESIARIGHT VENTRICLERV ejects blood into the pulmonary arteries for oxygenation and removal of CO2 by the lungsTricuspid valvePulmonary valveMuscle wall thickness 4-5 mmPapillary muscles have attachments to the ventricular walls and chordae tendineaeChordae tendineae are attached to the cusps of the tricuspid valveChordae tendineae and papillary muscles help to prevent the eversion of the tricuspid valve

CARDIAC ANESTHESIALEFT ATRIUMLA acts as a reservoir for oxygenated blood from pulmonary veins and a pump during ventricular diastoleProvides a 20 - 30% increase in left ventricular end-diastolic volume (LVEDV), atrial kickCompromised patients rely on this kick to maintain an adequate COLA located superiorly and posteriorly to other cardiac chambersMuscle wall thickness ~3 mmMitral valve connects LA to LVAtrial wall is smooth, may contain a central depression

CARDIAC ANESTHESIALEFT VENTRICLELV ejects blood into the aortaLV wall thickness is ~8 to 15 mmVentricular septum separates the RV and LV cavitiesUpper third of septum smooth endocardiumRemaining two thirds of septum and rest of ventricular wall covered with trabeculae carneaePresent in the LV are two large papillary musclesChordae tendineae of each muscle are attached to the cusps of the mitral valve

CARDIAC ANESTHESIACARDIAC VALVESCardiac valves ensure a one-way flow of blood through the heartOpen and close in response to pressure gradients that exist above or below the valvesAV or semilunarCalculation of valve area accurate way to determine valvular pathologyEchocardiography used in the diagnosis of valvular disease

CARDIAC ANESTHESIAATRIOVENTRICULAR VALVESTRICUSPID VALVESituated within the right AV orificeThree leaflets of unequal size:AnteriorSeptalPosteriorLeaflets attached to chordae tendineae, which are attached to papillary musclesNormal tricuspid valve area is 7 cm2

CARDIAC ANESTHESIAATRIOVENTRICULAR VALVESMITRAL VALVESituated in the left AV orificeTwo major leaflets connected by commissural tissue:AnteromedialPosterolateralNormal mitral valve area is 4 6 cm2 Has papillary muscles and chordae tendineae attached to the leaflets

CARDIAC ANESTHESIASEMILUNAR VALVESAortic and pulmonary valve configuration is similarThe cusps of the aortic valve are slightly thicker due to being subjected to higher pressuresSemilunar valves situated within the outflow tracts of their corresponding ventriclesEach valve is composed of three cuspsAbove the aortic valve is a dilation known as the sinus of ValsalvaNormal valve area of the aortic valve is 1 - 3 cm2

CARDIAC ANESTHESIAVALVULAR HEART DISEASEGeneral evaluation:Regardless of the lesion or its cause, preoperative evaluation should be primarily concerned with determining the severity of the lesion and its hemodynamic significance, residual ventricular function, and the presence of secondary effects on organ functionConcomitant coronary artery disease should be evaluatedMyocardial ischemia may present in patients with severe aortic stenosis or regurgitation

CARDIAC ANESTHESIAVALVULAR HEART DISEASEHistory:Should focus on symptoms related to ventricular function:Questions should concern exercise tolerance, fatigability, and pedal edema and shortness of breath in general, when lying flat, or at nightInquire about chest pains and neurologic symptoms and prior proceduresReview of medication should be evaluated

CARDIAC ANESTHESIAVALVULAR HEART DISEASESpecial diagnostic studies:Echocardiography, angiography, and cardiac catheterization provide significant diagnostic and prognostic information about valvular lesionsMore than one valvular lesion may be foundImportant to note:Severity of lesionDegree of ventricular impairmentHemodynamic significance of abnormalityConcomitant coronary artery disease

CARDIAC ANESTHESIAAORTIC VALVE REPLACEMENTDisease of the aortic valve may present as valvular stenosis, insufficiency, or a combination of the twoMost commonly occurs as a result of rheumatic disease and may occur secondary to calcific degenerationUsual preoperative diagnosis: severe AS with syncope, chest pain or CHF; aortic insufficiency with CHFMost conditions require valve replacement Three most commonly used prostheses:Porcine bioprosthesesMechanical prosthesesCryo-preserved homografts

CARDIAC ANESTHESIAAORTIC VALVE REPLACEMENTSurgical procedure, on full CPB, is usually performed through a median sternotomyCardioplegia administration is achieved either antegrade or retrogradeAfter the heart is arrested , the aorta is opened to expose the aortic valveCalcium deposits must be debrided to allow the prosthetic valve to be securely seatedProsthesis lowered into the annulus and securely sutured in place

CARDIAC ANESTHESIAMITRAL VALVE REPAIR OR REPLACEMENTMitral valve repair or replacement is utilized typically for:Correction of post-rheumatic mitral valvular stenosis or insufficiencyMitral valve prolapseDegenerative mitral insufficiencyRepair following endocarditisUsual preoperative diagnosis: class III or IV CHF secondary to mitral insufficiency or mitral stenosisMitral valve repair; for mitral regurgitation secondary to posterior leaflet abnormalitiesMitral valve replacement; for severe rheumatic calcific mitral stenosis

CARDIAC ANESTHESIATRICUSPID VALVE REPAIRInsufficiency of the tricuspid valve is almost always due to left-side valvular diseaseCongenital conditions may persist into early adulthood necessitating consequent replacementTricuspid repair is normally possible in the absence of primary involvement of tricuspid leafletsProcedure usually accomplished on CPB either with the heart fibrillating or during a brief period of aortic cross-clamping and diastolic arrestTemporary pacing wires are usually inserted

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherAnesthesia and OR set-up:Standard machine, suction, and defibrillator checkAirway set-up:#8.0 oral ETTNasal cannula for preoperative line placementOral gastric tube placed following TEE at end of caseIV poles with at least two double infusion pumpsIVs set-up and flushed, devoid of air in tubing; 1L NS (x2) with blood tubing for PIV and cordis

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherAnesthetic interview:H&P, labs, diagnostic tests; stress test, echo, cardiac catheterization, availability of blood and blood productsPatient educationConfirm patient ID band to patient ID plateVerify consent

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherPremedication:Benzodiazepines and opioidsMedications:STP mixedFentanylVersedSuccinylcholine and NDMRNeosynephrine, ephedrine, and NTGAncef 1 Gm mixed

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherPre-induction:Anesthesia monitors applied; ECG (obtain baseline), NIBP, pulse oximeter (band-aid type)Oxygen at 3L/NCAdditional sedationInsertion of PIVsInvasive monitoring placed; PA catheter (obtain CO)Administration of ATB

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherInduction of anesthesia; opioids, STP, muscle relaxantLaryngoscopy and intubation; secure ETTVolatile anesthetic agent (N2O not used)Obtain post-induction CO/CIMaintain MAP in 70sTEE completed

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherPre-cardiopulmonary bypass:Disconnect ETT (lungs down for sternotomy)Lower MAP (400 sec.) acceptableExpect hypotension with direct surgical manipulationEmpty and record urinary output

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherCardiopulmonary bypassDiscontinue all IV fluids, turn off ventilator and gases, disconnect ETT from circuit, ask if any infusions should be maintained during CPBWithdraw PA catheter 4-5 cmCardioplegia administeredContinued dosing of fentanyl, versed, and NDMR prnMonitor urinary outputCalculate drug dosages for post-bypass infusions

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherWeaning CPBWhile rewarming check TOF; redose NDMR, versed, and fentanyl prn. During rewarming sweating may be presentSurgeon will ask for lungs to be inflatedPlace on ventilator when directedObtain CO/CI and TEE when off pump (insert OGT)Protamine when requestedDefibrillation with internal paddles and AV pacing is at times necessary

CARDIAC ANESTHESIAVALVULAR REPAIR OR REPLACEMENTPutting it all togetherPrepare for transportEmergency equipmentResuscitation medicationsICU note to include:Transported with monitorsAmbu 100% O2Record: VS, PA, CVP, and CO/CIVentilator settings; rate, volume, FIO2, PEEP, PS

CARDIAC ANESTHESIANEW ALTERNATIVES TO TRADITIONAL PROCEDURESPercutaneous valve replacementCurrently focused on the aortic valvePatient population:Patients who are deemed too sick for traditional valve replacementWith minimally invasive procedure; diseased valve is not removed it is propped open and an artificial valve is wedged into the stenotic openingUncertain whether they will function and last as well as traditional valve replacementsCould replacing a valve become an overnight procedure!!!...

CARDIAC ANESTHESIAREFERENCESMorgan, G.E., Mikhail, M.S., and Murray, M.J. (2002).Clinical Anesthesiology. (3rd Ed.) New York, NY:McGraw-Hill.Nagelhout, J.J. and Zaglaniczny, K.L. (2005). NurseAnesthesia. (3rd Ed.) St. Louis, MO: Elsevier-Saunders.Wasnick, J.D. (1998). Handbook of Cardiac Anesthesia and Perioperative Care. Boston, MA: Butterworth-Heinemann.