Evaluation of the Cardiac Patient for Non-cardiac Surgery

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Evaluation of the Cardiac Patient for Non-cardiac
Surgery

• Vincent Conte, MD
• Attending Anesthesiologist and
• Director of Anesthesia Services at
• Baptist Childrens Hospital (Ret.)
• Assistant Clinical Professor
• FIU School of Nursing

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Introduction

• Patients with co-existing Cardiac disease will be
  coming for surgery very frequently for
  NON-cardiac procedures
• Familiarity with the AHA/ACC Guidelines is very
  important to be able to adequately assess the
  status of these patients.

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Topics of Discussion

• Familiarize yourselves with the AHA/ACC
  Guidelines
• Learn to identify which patients present a
  significant risk of having a cardiac event
  intraoperatively
• Learn what steps in the evaluation process are
  important to be done preoperatively to further
  identify which patients are at risk

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Prevalence of Cardiovascular Disease

• Estimated 22,000,000 US Adults have significant
  Coronary Artery Disease 17 per 1000 (2004 AHA)
• Of these, 6,400,000 have active or unstable
  angina
• Another 50,000,000 have Hypertension (16) 217
  per 1000
• There are 4,600,000 Strokes each year in the US
  and 4,800,000 new cases of CHF

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Prevalence of Cardiovascular Disease

• That brings the total number of Americans who
  have some type of Cardiovascular disease to
  77,000,000 or 26 of the total population
• The more alarming statistic is that approx. 14
  of patients with Hypertension and a normal
  resting EKG have undiagnosed SIGNIFICANT Coronary
  Artery disease

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Cardiac Predictors

• All of the flow charts and models are based on
  factors that are called Cardiac Predictors
• They are graded as Minor, Intermediate, and Major
• The preop evaluation all depends on which
  predictors are present and how many as well

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Minor Cardiac Predictors
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Intermediate Cardiac Predictors
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Major Cardiac Predictors
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Flow Charts Based on Predictors

• The following are the flow charts created by the
  AHA/ACC based on which and how many predictors
  are present preoperatively
• Also keep in mind that your clinical judgment has
  a lot to do with what level you place the patient
  at within the flow charts
• If you think the patient is sicker than they look
  on paper, do not hesitate to place them in a
  higher risk category to start with

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MET Scale

• Also used to place patients at their appropriate
  positions in the flow charts is the MET Scale
• This is based on a measure called a Metabolic
  Unit
• A unit is proportional to a certain amount of
  physical exertion
• Based on how many METs a person is functioning
  at, an approximation of their cardiac status can
  be made
• IT IS VERY SUBJECTIVE, but can still act as a
  quick screening scale to rapidly assess overall
  cardiac status and health

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MET Scale
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Intermediate Predictors
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Cardiac Assessment

• You can see that for the most part, the charts
  are easy to follow and do a good job of
  delineating who and where a patient should be
  placed in the sequence
• However, a grey area exists with respect to newly
  diagnosed Valvular Heart Disease that is deemed
  mild by the Cardiologist
• Some feel that this should be a MAJOR indicator
  while others feel that it should be an
  INTERMEDIATE indicator

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Cardiac Risk Assessment

• Other factors may help you determine what
  category to put such patients.
• Co-existing Hypertension or DM may bump them up
  to MAJOR while a lack of symptoms and no other
  co-existing disease may keep them in INTERMEDIATE
• Regardless, a quick phone consultation should be
  made with the Cardiologist and his
  recommendations should be noted in the chart as
  well as documenting that you DID contact the
  Cardiologist in this matter
• Then you would just proceed along the recommended
  Anesthesia Treatment guidelines for whichever
  Valvular lesion the patient might have

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Common Intraoperative Cardiac Conditions

• The most common Cardiac complications you may
  encounter in the OR are
• ST Segment changes (Intraop Ischemia)
• Myocardial Infarction
• Sinus Bradycardia
• Non-lethal Ventricular Arrhythmias
• Pulmonary Edema

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ST Segment Changes

• This event can manifest as either elevation or
  depression of the ST Segment
• The etiology can vary
• 1) Inadequate coronary perfusion vs. demand (AS)
• 2) Acute Myocardial Ischemia or Infarction
• 3) Myocardial contusion (Trauma)
• 4) Electrolyte abnormalities (hypo/hyperkalemia,
  hypercalcemia)
• 5) Head injury with raised ICP and elevated
  systemic blood pressure
• 6) Hypothermia
• 7) Post-Defibrillation injury

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ST Segment Changes

• Typically, this is seen in
• Patients with pre-existing CAD
• Any changes causing either an increase in
  myocardial O2 demand or decreased supply
  (Tachycardia, hypertension/hypotension,
  hypoxemia, hemodilution, or Coronary spasm)
• After head or chest trauma
• During vaginal delivery or C-section

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ST Segment Changes

• PREVENTION
• Carefully evaluate and prepare patients with CAD
  preoperatively
• Carefully manage hemodynamics and hematocrit to
  optimize myocardial O2 Balance
• Identify and evaluate pre-existing ST segment
  abnormalities preoperatively

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ST Segment Changes

• Manifestations
• In an awake patient, they may describe Chest pain
  radiating into the arms and throat
• Dyspnea
• Nausea and vomiting
• Altered level of consciousness or cognitive
  function

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ST Segment Changes

• EKG/Systemic Manifestations
• Depression or elevation of the ST segment from
  the isoelectric level
• Development of Q waves
• Arrhythmias (PVCs, ventricular tachycardia,
  Ventricular fibrillation
• Hypotension
• Elevated ventricular filling pressures (stiff
  ventricle)
• V wave on pulmonary artery wedge tracing

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ST Segment Changes

• Management
• Verify ST segment changes (check lead placement,
  compare to previous EKGs)
• Ensure adequate oxygenation and ventilation
  (check pulse oximeter, capnograph, send an ABG)
• Treat tachycardia and/or hypertension (B-Blockade
  with Esmolol, Labetolol, incr. depth of
  anesthesia)
• NTG IV Infusion, 0.25-2micrograms/kg/min
  (titrate to desired effect)
• Calcium Channel Blockade (Verapamil IV 2.5 mg,
  Diltiazem IV 2.5 mg

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ST Segment Changes

• Management
• 6) Treat hypotension and/or bradycardia
• 7) Optimize circulating fluid volume
• 8) Support myocardial contractility as needed
  using inotropic agents (Ephedrine, Dopamine,
  Dobutamine, Epinephrine)
• 9) AVOID NTG/CA Blockers until hypotension or
  bradycardia are resolved
• 10) Inform the surgeon if possible terminate
  procedure early
• 11) Send blood chemistries (ABG, H/H,
  Electrolytes, Glucose, CK-MB, Troponin)
• 12) Treat underlying causes of ST Segment changes
  if other than Myocardial Ischemia

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ST Segment Changes

• COMPLICATIONS
• Myocardial Infarction
• Arrhythmias
• Cardiac Arrest
• Complications from placement of PA catheter
• Complications from placement of TEE

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Myocardial Infarction

• Defined as myocardial cell death due to
  inadequate cellular perfusion.
• Transmural (Q wave) infarctions involve the
  entire thickness of the myocardial wall
• Subendocardial (non-Q wave) infarctions involve
  only the subendocardial portion of the myocardial
  wall

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Myocardial Infarction

• Etiology
• Acute occlusion of a coronary artery (thrombus,
  plaque)
• Inadequate coronary perfusion for a given
  myocardial O2 demand
• Acute dissection of the aorta

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Myocardial Infarction

• Typical Situations
• In patients with pre-existing CAD/Angina Pectoris
• In older patients (gt70 years old)
• Patients with peripheral vascular disease
• Patients with DM (silent myocardial ischemia)
• During any acute change in myocardial O2 demand
  or delivery (Tachycardia, hypertension,
  hypotension, hypoxemia, hemodilution, or Coronary
  spasm)
• Patients with Aortic or Mitral STENOSIS
• Patients with recent CABG surgery
• Acute Carbon Monoxide poisoning

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Myocardial Infarction

• Prevention
• Carefully evaluate and prepare patients with CAD
  preoperatively (evaluate myocardial function and
  reserve is patient optimized?)
• Avoid elective anesthesia and surgery in patients
  with Unstable Angina or with a h/o MI in the
  previous 6 months
• Optimize hemodynamics and hematocrit during
  anesthesia

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Myocardial Infarction

• Manifestations
• Differentiated from Ischemia by persistence and
  progression of ST segment and T wave changes
• Elevated cardiac isoenzymes
• Awake patient with chest pain, dyspnea, nausea
  and vomiting
• EKG abnormalities (ST depressions/elevations
  hyperacute, prominent T waves development of Q
  waves)
• Arrhythmias (PVCs, V Tach, V Fib, AV Block,
  Bundle branch block)
• Hypotension, Tachycardia/Bradycardia
• Elevated Ventricular filling pressures

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Myocardial Infarction

• Management
• VERIFY manifestations of ongoing myocardial
  ischenia (if patient is awake assess clinical
  signs and symptoms, check lead placement and
  check multiple leads, obtain a 12-lead EKG ASAP,
  evaluate hemodynamic status)
• INFORM the surgeon and terminate surgery ASAP
• Request ICU bed ASAP
• If present, treat Ventricular Arrhythmias (Lido
  IV 1-1.5mg/kg bolus, then 1-4mg/min Procainamide
  IV 500mg over 10-20 minutes, then 2-6mg/min)

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Myocardial Infarction

• Management
• 5) Place an arterial line and monitor blood
  pressure VERY carefully
• 6) Treat tachycardia (MOST important!!) and/or
  hypertension (increase depth of anesthesia,
  B-Blockade w/ Esmolol, Labetolol and/or Cardene
  for hypertension)
• 7) NTG IV _at_ 0.25-2 microgms/min (titrate PRN)
• 8) CA Channel Blockers (Verapamil IV 2.5 mg and
  repeat as needed, or Diltiazem IV 2.5 mg, also
  repeat as needed)
• 9) If hypotension develops, maintain BP with
  Neosynephrine and volume (cardiac perfusion takes
  precedence over afterload reduction)

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Myocardial Infarction

• Management
• 10) Consider placing an SG cath to guide with
  fluid management (go by LVEDP to avoid overload)
• 11) Support myocardial contractility as needed
  with Inotropes such as Dopamine, Dobutamine, Epi
  (use with EXTREME caution as these will also
  increase myocardial O2 demand)
• 12) Avoid NTG and CA Channel Blockers until
  hypotension or bradycardia are resolved
• 13) Treat pain and anxiety if patient is awake
• 14) Send Labs (ABGs, H/H, electrolytes, CK,
  CK-MB, Troponins)
• 15) If hypotension persists consider placement of
  an IABP to decrease workload of myocardium and
  allow to rest and recooperate

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Myocardial Infarction

• Complications
• CHF
• Arrhythmias
• Cardiac Arrest
• Thrombus formation and complications from their
  migration
• Papillary muscle dysfunction or rupture
• Rupture of Interventricular septum or ventricular
  wall

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Sinus Bradycardia

• Definition A heart rate less than 60 bpm in an
  adult, in which the impulse formation begins in
  the sinus node
• Etiology
• Increased vagal tone (vaso-vagal, valsalva)
• Drug induced
• Hypoxemia
• Cardiac Ischemia
• Hypothermia
• Hypothyroidism
• Brain injury with herniation
• Physiologic (congenital physical conditioning)

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Sinus Bradycardia

• Typical Situations
• An isolated finding during preop evaluation
• Following administration of drugs (Narcotics,
  Halothane, B-Blockers, CA Channel blockers,
  Anticholinesterases, A2-agonists Clonidine)
• During Vagal stimulation (Traction on eye or
  peritoneum, Laryngoscopy and Intubation, Bladder
  catheterization)
• During hypertensive episodes (Baroreceptor
  reflex)
• During spinal/epidural anesthesia w/ high level
• ECT

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Sinus Bradycardia

• Prevention
• Premedicate patients at risk with
  anticholinergics (Atropine IM 0.4 mg, Robinul IM
  0.2 mg)
• Treat bradycardia early during high
  spinal/epidurals (Atropine IV 0.4-0.8mg, Robinul
  IV 0.2-0.4mg)
• Avoid excess traction on peritoneum or
  extraoccular muscles
• Avoid excess manipulation of the carotid sinus

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Sinus Bradycardia

• Manifestations
• Slow heart rate on EKG, Pulse Oximeter, A-Line,
  NIBP Monitor, palpation of peripheral pulses
• Hypotension
• Symptoms in a conscious patient Nausea,
  Vomiting, Change in mental status
• Junctional or Idioventricular escape beats

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Sinus Bradycardia

• Management
• Verify bradycardia and assess its hemodynamic
  significance (Check MULTIPLE monitors to confirm
  or palpate a peripheral pulse)
• Ensure adequate oxygenation and ventilation
  (bradycardia is common with hypoxic conditions
  esp. in pediatric patients)
• Call for help if significant hemodynamic changes
  are associated with the bradycardia

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Sinus Bradycardia

• Management
• 4) If bradycardia IS associated with SEVERE
  hypotension, loss of consciousness or seizures,
  Rx with Epi IV, 10microgram bolus (1cc) and
  repeat as needed until desired effect is achieved
• 5) If Bradycardia fails to resolve with Epi,
  consider Transcutaneous pacing and Isoproterenol
  infusion at 1-3 micrograms/min.
• 6) Begin CPR if necessary

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Sinus Bradycardia

• Management
• 7) If bradycardia is associated with only mild to
  moderate hypotension (10-15 drop from pre-brady
  rate), RX with Ephedrine IV in 5-10 mg increments
  and/or Atropine IV 0.4mg and/or Robinul IV 0.2mg
  Repeat above as necessary until desired effects
  obtained
• 8) Scan surgical field once brady is treated for
  possible physical causes if none are present,
  observe patient closely both intra and post-op

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Sinus Bradycardia

• Complications
• Escape arrhythmias (Junctional/Idioventricular)
• Cardiac Arrest
• Complications with pacer operation or placement
• Tachyarrhythmias and hypertension secondary to
  drug treatment (overtreatment will result in
  chasing your own tail)

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Non-Lethal Ventricular Arrhythmias

• Definition
• Nonlethal ventricular (wide QRS complex)
  arrhythmias NOT requiring ACLS although they may
  eventually lead to ventricular fibrillation

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Non-Lethal Ventricular Arrhythmias

• Etiology
• PVCs
• Abnormal automaticity of ventricular myocardium
• Re-entry phenomena
• Drug Toxicity
• R on T phenomenon

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Non-Lethal Ventricular Arrhythmias

• Typical Situations
• PVCs provoked by tea, coffee, alcohol, tobacco,
  or emotional excitement
• Patients with Myocardial Ischemia or infarction
• Hypoxemia and/or hypercarbia
• Potassium and/or Acid Base disturbances
• Patients with Mitral Valve Prolapse
• Excessive depth of anesthesia

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Non-Lethal Ventricular Arrhythmias

• Typical Situations
• 7) Direct Mechanical stimulation of the heart
• 8) Acute hypertension and/or tachycardia
• 9) Acute HYPOtension and/or bradycardia
• 10) Drugs (Halothane, Dig, Tricyclics,
  Aminophylline, antihistamines
• 11) Hypothermia

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Non-Lethal Ventricular Arrhythmias

• Manifestations
• Wide QRS complex on EKG NOT preceeded by a P wave
• PVCs
• Ventricular tachycardia
• Torsade de pointes (paroxysms of V-tach in which
  the QRS axis changes direction continuously)

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Non-Lethal Ventricular Arrhythmias

• Management
• Ensure adequate oxygenation and ventilation
• Check if the arrhythmia is hemodynamically
  significant
• If it is Lidocaine IV 1-1.5 mg bolus consider
  synchronized countershock if change is severe
• Diagnose the arrhythmia
• If V-tach is present repeat Lido q/15 min and
  start infusion at 1-4 mg/min consider synched
  countershock

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Non-Lethal Ventricular Arrhythmias

• Management
• 6) If Torsade de pointes is present give MgSO4,
  1-2 g bolus followed by infusion at 1 mg/min
• 7) If PVCs ONLY are present with Tachycardia and
  Hypertension deepen anesthesia with
  IV/inhalational agents
• 8) Evaluate for possible myocardial ischemia

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Summary

• Cardiac disease is becoming more and more
  prevalent every year, so the fraction of your
  patients who will have significant Cardiac
  Disease will also be on the rise
• Careful Preop evaluation and testing WILL reduce
  the morbidity and mortality associated with any
  patient who has pre-existing Cardiac disease

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Summary

• Unfortunately, due to time pressures and Surgeon
  pressures, you may be tempted to just Go for it
  and hope for the best BUT
• DONT
• It will ultimately be your ass hung out to dry
  and the surgeon will be saying that Anesthesia
  never really told me how sick the patient was
• Stick to your guns and make sure that the PATIENT
  and their safety comes FIRST!!!!!!!