CARDIAC ANESTHESIA PART III

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CARDIAC ANESTHESIAPART III

• DENNIS STEVENS CRNA, MSN, ARNP
• JULY 2006
• FLORIDA INTERNATIONAL UNIVERSITY
• PRINCIPLES OF ANESTHESIOLOGY NURSING III
• NGR 6094

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CARDIAC ANESTHESIA

• OBJECTIVES
• Discuss 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.

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CARDIAC ANESTHESIA

• CARDIAC SKELETON
• Tough fibrous rings surround the AV valves and
  act as points of attachment
• Two additional fibrous annuli develop in relation
  to the bases of the aorta and the pulmonary trunk
• Annulus fibrosis is the fixation point for
  cardiac musculature and plays an important role
  in the structure, function, and efficiency of the
  heart

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CARDIAC ANESTHESIA

• CHAMBERS OF THE HEART
• The atria are smaller and thinner walled than the
  ventricles
• Ventricles have a thicker myocardial layer and
  make up much of the bulk of the heart
• Atria are storage units and conduits for blood
  that is emptied into the ventricles
• Ventricles must propel blood through pulmonary or
  systemic circulation

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CARDIAC ANESTHESIA

• RIGHT ATRIUM
• RA serves as a reservoir for the RV
• Muscle wall thickness of 2 mm
• RA receives blood from SVC, IVC, and coronary
  sinus
• RA consists of two parts
• Anterior, thin-walled trabeculated portion
• Posterior, smooth-walled portion
• Interatrial septum
• Fossa ovalis cordis

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CARDIAC ANESTHESIA

• RIGHT VENTRICLE
• RV ejects blood into the pulmonary arteries for
  oxygenation and removal of CO2 by the lungs
• Tricuspid valve
• Pulmonary valve
• Muscle wall thickness 4-5 mm
• Papillary muscles have attachments to the
  ventricular walls and chordae tendineae
• Chordae tendineae are attached to the cusps of
  the tricuspid valve
• Chordae tendineae and papillary muscles help to
  prevent the eversion of the tricuspid valve

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CARDIAC ANESTHESIA

• LEFT ATRIUM
• LA acts as a reservoir for oxygenated blood from
  pulmonary veins and a pump during ventricular
  diastole
• Provides a 20 - 30 increase in left ventricular
  end-diastolic volume (LVEDV), atrial kick
• Compromised patients rely on this kick to
  maintain an adequate CO
• LA located superiorly and posteriorly to other
  cardiac chambers
• Muscle wall thickness 3 mm
• Mitral valve connects LA to LV
• Atrial wall is smooth, may contain a central
  depression

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CARDIAC ANESTHESIA

• LEFT VENTRICLE
• LV ejects blood into the aorta
• LV wall thickness is 8 to 15 mm
• Ventricular septum separates the RV and LV
  cavities
• Upper third of septum smooth endocardium
• Remaining two thirds of septum and rest of
  ventricular wall covered with trabeculae carneae
• Present in the LV are two large papillary muscles
• Chordae tendineae of each muscle are attached to
  the cusps of the mitral valve

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CARDIAC ANESTHESIA

• CARDIAC VALVES
• Cardiac valves ensure a one-way flow of blood
  through the heart
• Open and close in response to pressure gradients
  that exist above or below the valves
• AV or semilunar
• Calculation of valve area accurate way to
  determine valvular pathology
• Echocardiography used in the diagnosis of
  valvular disease

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CARDIAC ANESTHESIA

• ATRIOVENTRICULAR VALVES
• TRICUSPID VALVE
• Situated within the right AV orifice
• Three leaflets of unequal size
• Anterior
• Septal
• Posterior
• Leaflets attached to chordae tendineae, which are
  attached to papillary muscles
• Normal tricuspid valve area is 7 cm2

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CARDIAC ANESTHESIA

• ATRIOVENTRICULAR VALVES
• MITRAL VALVE
• Situated in the left AV orifice
• Two major leaflets connected by commissural
  tissue
• Anteromedial
• Posterolateral
• Normal mitral valve area is 4 6 cm2
• Has papillary muscles and chordae tendineae
  attached to the leaflets

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CARDIAC ANESTHESIA

• SEMILUNAR VALVES
• Aortic and pulmonary valve configuration is
  similar
• The cusps of the aortic valve are slightly
  thicker due to being subjected to higher
  pressures
• Semilunar valves situated within the outflow
  tracts of their corresponding ventricles
• Each valve is composed of three cusps
• Above the aortic valve is a dilation known as the
  sinus of Valsalva
• Normal valve area of the aortic valve is 1 - 3
  cm2

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CARDIAC ANESTHESIA

• VALVULAR HEART DISEASE
• General 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 function
• Concomitant coronary artery disease should be
  evaluated
• Myocardial ischemia may present in patients with
  severe aortic stenosis or regurgitation

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CARDIAC ANESTHESIA

• VALVULAR HEART DISEASE
• History
• 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 night
• Inquire about chest pains and neurologic symptoms
  and prior procedures
• Review of medication should be evaluated

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CARDIAC ANESTHESIA

• VALVULAR HEART DISEASE
• Special diagnostic studies
• Echocardiography, angiography, and cardiac
  catheterization provide significant diagnostic
  and prognostic information about valvular lesions
• More than one valvular lesion may be found
• Important to note
• Severity of lesion
• Degree of ventricular impairment
• Hemodynamic significance of abnormality
• Concomitant coronary artery disease

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CARDIAC ANESTHESIA

• AORTIC VALVE REPLACEMENT
• Disease of the aortic valve may present as
  valvular stenosis, insufficiency, or a
  combination of the two
• Most commonly occurs as a result of rheumatic
  disease and may occur secondary to calcific
  degeneration
• Usual preoperative diagnosis severe AS with
  syncope, chest pain or CHF aortic insufficiency
  with CHF
• Most conditions require valve replacement
• Three most commonly used prostheses
• Porcine bioprostheses
• Mechanical prostheses
• Cryo-preserved homografts

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CARDIAC ANESTHESIA

• AORTIC VALVE REPLACEMENT
• Surgical procedure, on full CPB, is usually
  performed through a median sternotomy
• Cardioplegia administration is achieved either
  antegrade or retrograde
• After the heart is arrested , the aorta is opened
  to expose the aortic valve
• Calcium deposits must be debrided to allow the
  prosthetic valve to be securely seated
• Prosthesis lowered into the annulus and securely
  sutured in place

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CARDIAC ANESTHESIA

• MITRAL VALVE REPAIR OR REPLACEMENT
• Mitral valve repair or replacement is utilized
  typically for
• Correction of post-rheumatic mitral valvular
  stenosis or insufficiency
• Mitral valve prolapse
• Degenerative mitral insufficiency
• Repair following endocarditis
• Usual preoperative diagnosis class III or IV CHF
  secondary to mitral insufficiency or mitral
  stenosis
• Mitral valve repair for mitral regurgitation
  secondary to posterior leaflet abnormalities
• Mitral valve replacement for severe rheumatic
  calcific mitral stenosis

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CARDIAC ANESTHESIA

• TRICUSPID VALVE REPAIR
• Insufficiency of the tricuspid valve is almost
  always due to left-side valvular disease
• Congenital conditions may persist into early
  adulthood necessitating consequent replacement
• Tricuspid repair is normally possible in the
  absence of primary involvement of tricuspid
  leaflets
• Procedure usually accomplished on CPB either with
  the heart fibrillating or during a brief period
  of aortic cross-clamping and diastolic arrest
• Temporary pacing wires are usually inserted

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Anesthesia and OR set-up
• Standard machine, suction, and defibrillator
  check
• Airway set-up
• 8.0 oral ETT
• Nasal cannula for preoperative line placement
• Oral gastric tube placed following TEE at end of
  case
• IV poles with at least two double infusion pumps
• IVs set-up and flushed, devoid of air in tubing
  1L NS (x2) with blood tubing for PIV and cordis

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Anesthetic interview
• HP, labs, diagnostic tests stress test, echo,
  cardiac catheterization, availability of blood
  and blood products
• Patient education
• Confirm patient ID band to patient ID plate
• Verify consent

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Premedication
• Benzodiazepines and opioids
• Medications
• STP mixed
• Fentanyl
• Versed
• Succinylcholine and NDMR
• Neosynephrine, ephedrine, and NTG
• Ancef 1 Gm mixed

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Pre-induction
• Anesthesia monitors applied ECG (obtain
  baseline), NIBP, pulse oximeter (band-aid type)
• Oxygen at 3L/NC
• Additional sedation
• Insertion of PIVs
• Invasive monitoring placed PA catheter (obtain
  CO)
• Administration of ATB

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Induction of anesthesia opioids, STP, muscle
  relaxant
• Laryngoscopy and intubation secure ETT
• Volatile anesthetic agent (N2O not used)
• Obtain post-induction CO/CI
• Maintain MAP in 70s
• TEE completed

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Pre-cardiopulmonary bypass
• Disconnect ETT (lungs down for sternotomy)
• Lower MAP (lt70) during aortic/RA cannulation
• May be asked to hand bag
• Heparin is calculated (300U/kg) and administered
  aspirate blood (via cordis) pre/post heparin and
  protamine administration
• ACT checked (gt400 sec.) acceptable
• Expect hypotension with direct surgical
  manipulation
• Empty and record urinary output

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Cardiopulmonary bypass
• Discontinue all IV fluids, turn off ventilator
  and gases, disconnect ETT from circuit, ask if
  any infusions should be maintained during CPB
• Withdraw PA catheter 4-5 cm
• Cardioplegia administered
• Continued dosing of fentanyl, versed, and NDMR
  prn
• Monitor urinary output
• Calculate drug dosages for post-bypass infusions

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Weaning CPB
• While rewarming check TOF redose NDMR, versed,
  and fentanyl prn. During rewarming sweating may
  be present
• Surgeon will ask for lungs to be inflated
• Place on ventilator when directed
• Obtain CO/CI and TEE when off pump (insert OGT)
• Protamine when requested
• Defibrillation with internal paddles and AV
  pacing is at times necessary

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CARDIAC ANESTHESIA

• VALVULAR REPAIR OR REPLACEMENT
• Putting it all together
• Prepare for transport
• Emergency equipment
• Resuscitation medications
• ICU note to include
• Transported with monitors
• Ambu 100 O2
• Record VS, PA, CVP, and CO/CI
• Ventilator settings rate, volume, FIO2, PEEP, PS

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CARDIAC ANESTHESIA

• NEW ALTERNATIVES TO TRADITIONAL PROCEDURES
• Percutaneous valve replacement
• Currently focused on the aortic valve
• Patient population
• Patients who are deemed too sick for
  traditional valve replacement
• With minimally invasive procedure diseased valve
  is not removed it is propped open and an
  artificial valve is wedged into the stenotic
  opening
• Uncertain whether they will function and last as
  well as traditional valve replacements
• Could replacing a valve become an overnight
  procedure!!!...

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CARDIAC ANESTHESIA

• REFERENCES
• Morgan, 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).
  Nurse
• Anesthesia. (3rd Ed.) St. Louis, MO Elsevier-
• Saunders.
• Wasnick, J.D. (1998). Handbook of Cardiac
  Anesthesia and Perioperative Care. Boston, MA
  Butterworth-Heinemann.