Preoperative Evaluation

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Preoperative Evaluation

• B. Wayne Blount, MD, MPH
• Professor, Emory

2

• 67 of consultations were for preoperative
  evaluation. In 12 of cases, the findings of the
  consultation resulted in a significant change in
  perioperative management in 7, surgery was
  delayed a decision was made to cancel surgery
  altogether in 2 of cases.
• Mollema, et al (2000) Neth J Med 567

3
Why Preoperative Evaluation?

• 10 percent of the United States population
  undergoes non-cardiac surgery annually.
• Over 8 million have known CAD or cardiac risk
  factors.
• Over 50,000 will suffer a perioperative
  myocardial infarction. (0.2)

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• The purpose of preoperative evaluation is not to
  give medical clearance, but rather to perform an
  evaluation of the patients current medical
  status make recommendations concerning the
  evaluation, management, and risk of cardiac
  problems over the entire perioperative period
  and provide a clinical risk profile that the
  patient, primary physician, anesthesiologist, and
  surgeon can use in making treatment decisions
• Kim A. Eagle, FACC, Chair, ACC/AHA Task Force on
  Practice Guidelines for Perioperative
  Cardiovascular Evaluation for Noncardiac
  Surgery

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What are You Really Being Asked to Do?

• Assess risks of anesthesia
• Assess the risks of the procedure
• Manage complicated medical problems
• Predict the future

6
General Considerations

• Limit number of recommendations
• Focus on critical problems
• Be specific about drugs, dosage and intervals
• Dont ask the surgeon to think

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Misconceptions

• Advise on type of anesthesia
• General, local or spinal
• Change ongoing treatment plans
• Initiate diagnostic work-ups
• If not in-patient doc, manage perioperative
  problems

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Steps to Preoperative Evaluation

• Surgical Risk Factors
• Patient Risk Factors
• Preoperative Testing
• Perioperative Management

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Risk Type of ProcedureACC/AHA Guidelines

• High risk (reported risk of adverse cardiac event
  gt5)
• Emergency surgery
• Aortic procedures
• Peripheral vascular surgery
• Prolonged surgical procedures associated with
  large volume shifts or high EBL
• A Rec

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Risk Duration of Anesthesia
Reilly, et al. (1999) Arch Int Med 1592185
Percent Complications
Duration (hours)
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Risk Type of ProcedureACC/AHA Guidelines

• Intermediate Risk (reported cardiac risk lt 5)
• Carotid endarterectomy
• Head and neck surgery
• Intraperitoneal and Intrathoracic
• Orthopedic surgery
• Prostate surgery
• A Rec

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Risk Type of ProcedureACC/AHA Guidelines

• Low risk (reported cardiac risk lt 1)
• Endoscopic procedures
• Superficial procedures
• Cataract surgery
• Breast surgery
• A Rec

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Steps to Preoperative Evaluation

• Surgical Risk Factors
• Patient Risk Factors
• Preoperative Testing
• Perioperative Management

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Patient Factors

• Exercise Capacity
• Medication use
• Obesity
• Age
• Labs EKG CXR PFT

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Whos at Risk B Rec

• Recent MI ( lt 30 days)
• Valvular heart disease
• CHF
• Unstable angina
• Diabetes

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Patient Factors Exercise Tolerance
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• McPhail, et al (1988) J Vasc Surgery 760
• Patients able to achieve 85 of their maximal
  predicted heart rate had a 6 cardiac
  complication rate, whereas patients unable to
  achieve 85 MPHR had a 24 rate of complications
  (p 0.04)
• Patients who had a positive stress test but
  achieved gt 85 MPHR had fewer cardiac
  complications.

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1 MET the oxygen consumption (VO2) of a 70 kg,
40 y.o. man at rest3.5 cc/kg/minDuke Activity
Status Index

• lt 4 METS gt 4 METS
• Baking Ice skating
• Slow dancing Moderate cycling
• Golfing with a cart Walking 4 mph
• Playing a musical instrument Heavy housework
• Walking 2 3 mph Skiing

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Exercise Capacity

• 4 METs -
• Two level blocks without symptoms
• One flight of stairs with two bags of groceries
• Poor exercise capacity lt four level blocks or
  two flights of stairs
• Complications
• Total 20 vs 10
• Cardiac 10 vs 5
• Pulmonary 9 vs 6 (not statistically signif.)

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Functional Capacity in METS

• 10 METS Excellent
• 7 10 METS Good
• 4 - 6 METS Moderate
• lt 4 METS Increased risk for
• cardiopulmonary complications

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Risk Patient FactorsMajor Clinical Predictors
ACC/AHA Guidelines

• Unstable coronary syndromes
• Decompensated CHF
• Significant arrhythmias
• Severe valvular disease

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Risk Patient FactorsIntermediate Clinical
PredictorsACC/AHA Guidelines

• Mild angina pectoris
• Prior MI
• Compensated or prior CHF
• Diabetes mellitus
• Renal insufficiency

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Risk Patient FactorsMinor Clinical
PredictorsACC/AHA Guidelines

• Advanced age
• Abnormal ECG
• Rhythm other than NSR
• Low functional capacity
• History of CVA
• Uncontrolled HTN

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Pulmonary Risks

• Complications
• Hypoventilation
• Pneumonia
• Atelectasis
• Occur in about a third of patients
• Accounts for half of perioperative mortality

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Whos at Risk

• Smokers
• COPD
• Obesity
• Age gt 70
• Thoracic surgery
• Upper abdominal surgery
• Anesthesia gt 2 hours

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PFTs B Rec

• No improvement over clinical eval
• Where the money is
• Decreased breath sounds
• Prolonged expiratory phase
• Rales, rhonchi, wheezes
• PFTs for unexplained dyspnea after good clinical
  eval

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Risk Assessment C Rec

• FEV1 gt 2L, probably safe
• FEV1 between 1 and 2L, increased risk
• FEV1 lt 1L, high risk

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Risk Management

• Quit smoking
• Bronchodilator therapy
• CPT (including incentive spirometry)
• Early treatment of bronchitis
• Early mobilization

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CXR C Rec

• Abnormalities not well associated with
  post-operative risk
• 0.1 affected management
• Routine use not recommended
• 2 exceptions
• gt 60y
• Suspected cardiac or pulmonary disease

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Steps to Preoperative Evaluation

• Surgical Risk Factors
• Patient Risk Factors
• Preoperative Testing
• Who
• How
• Perioperative Management

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Cardiac Testing Resting ECG

• Class I (definite indication)
• Recent ischemic symptoms
• Major / intermediate clinical predictors and high
  or intermediate risk procedure
• Class II (probably warranted)
• Asymptomatic diabetics
• History of cardiac revascularization
• Asymptomatic man gt 45 yo or woman gt 55 yo
• Prior hospitalization for cardiac causes
• Class III (not indicated)
• Asymptomatic patient low risk procedure

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Risk Type of ProcedureACC/AHA Guidelines

• High risk (reported risk of adverse cardiac event
  gt5)
• Emergency surgery
• Aortic procedures
• Peripheral vascular surgery
• Prolonged surgical procedures associated with
  large volume shifts or high EBL
• A Rec

33
Risk Type of ProcedureACC/AHA Guidelines

• Intermediate Risk (reported cardiac risk lt 5)
• Carotid endarterectomy
• Head and neck surgery
• Intraperitoneal and Intrathoracic
• Orthopedic surgery
• Prostate surgery
• A Rec

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Risk Patient FactorsMajor Clinical Predictors
ACC/AHA Guidelines

• Unstable coronary syndromes
• Decompensated CHF
• Significant arrhythmias
• Severe valvular disease

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Risk Patient FactorsIntermediate Clinical
PredictorsACC/AHA Guidelines

• Mild angina pectoris
• Prior MI
• Compensated or prior CHF
• Diabetes mellitus
• Renal insufficiency

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Echocardiography

• Class I (definite indication)
• Current or poorly-controlled CHF unless prior
  studies have documented severe ventricular
  dysfunction
• Class II (probably warranted)
• Prior CHF and no recent evaluation
• Dyspnea of unknown etiology
• Evidence of significant valvular disease
• Class III (not indicated)
• Routine testing of ventricular function in
  asymptomatic patients without a prior history of
  CHF

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Need for non-cardiac surgery
emergency
O. R.
elective
N
Y
Recurrent S/sx?
Recent cardiac revascularization ?
N
Y
Recent cardiac evaluation?
Favorable result?
N
Unfavorable result or change in sx?

• Clinical Predictors

ACC/AHA Guidelines
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Labs C Rec

• CBC
• Asymptomatic anemia lt1 prevalence
• Surgically significant anemia is even lower
• Mortality for surgery with expected blood loss
• Hct gt12 ? 1.3
• Hct lt 6 ? 33
• Remainder of CBC not useful (wbc,plt)

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Steps to Preoperative Evaluation

• Surgical Risk Factors
• Patient Risk Factors
• Preoperative Testing
• Who
• How
• Perioperative Management

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Perioperative Management Beta-Blockers

• Poldemans D, et al (1999) NEJM 3411789
• Cardiac complications and cardiac death was
  significantly less in the treatment group
  (p0.02)
• Bisoprolol 3.4
• Placebo 17.0
• Wallace A, et al (1998) Anesthesiology 887
• Patients treated with Atenolol had significantly
  fewer episodes of ischemia by continuous
  monitoring (p0.03)

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Beta Blockers

• Beta Blockers should be given perioperatively to
  patients with known ischemic heart disease
  undergoing vascular surgery or who have
  previously taken beta blockers A Rec
• Beta blockers generally are not recommended for
  patients with low to moderate risk B Rec

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Beta Blockers

• Long-acting better than shorter-acting ones
• Better when titrated to pulse of lt 65 bpm Rec B
• More effective when started at least 30 days
  prior to surgery AND continued thru hospital
  stay Rec C
• Fewer MIs, but more CVAs
• Need to do a risk analysis using Revised Cardiac
  Risk Index (RCRI). Use beta-blockers in pts with
  scores of gt 3.

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RCRI

• 1 Point each for
• High Risk Surgery
• Ischemic Heart Disease
• Cerebrovascular Disease
• Renal Insufficiency
• Diabetes

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Perioperative Beta-blockade to Prevent 1 Death

• NNT 33 with RCRI Score of 4
• NNT 62 with RCRI of 3
• NNT 227 with RCRI of 2
• NNT 864 with RCRI of 1
• NNK 504 with RCRI of 1
• Lindenaur. Perioperative Beta-Blocker. NEJM
  2005353349-61.
• POISE Study Grp. LancetMay 13, 2008

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Perioperative ManagementBlood Thinners

• 
  When to stop
• Aspirin (general indication) 14 days
• Aspirin (TIA / CVA / MI) 7 days
• NSAIDS 3-7 days
• Cox II inhibitors --------
• Clopidogrel (Plavix) 4-7 days
• Persantine 7 days
• Coumadin variable
• Herbal remedies 14 days
• (Gingko, Ginseng, Garlic, Feverfew)

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Perioperative Management of Selected Drugs
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Preoperative management of diabetics

• General anesthetic produces relative insulin
  hyposecretion and resistance due to changes in
  neuroendocrine balance (increased production of
  ACTH, catecholamines, GH, and glucagon).
• Postoperative factors such as inability to eat or
  absorb oral medications, use of steroids,
  hyperalimentation or tube feeds can affect
  glycemic control.
• Perioperatively
• Assess glycemic control preoperatively.
• Oral hypoglycemics can generally be continued up
  until the time of surgery but should not be taken
  on the morning of the procedure. Metformin
  should be held for 48 hours postoperatively, and
  then restarted only if renal and hepatic function
  are stable.
• The dose of intermediate and long-acting insulins
  should be reduced on the night prior to surgery.
• For long or complicated procedures in patients
  requiring insulin, intravenous insulin should be
  used in the immediate perioperative period. For
  short procedures, it may be possible to either
  delay the use of morning insulin, or use a
  fraction of the normal dose of intermediate-acting
  insulin.

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Risk Management

• Monitor for perioperative ischemia
• Repair severe aortic stenosis first
• Treat CHF aggressively preoperatively
• Postpone non-emergent procedures for at least 6
  months after an MI

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Summary

• Pre-op eval is not clearance
• Determine risks, then minimize
• Let surgeon, anesthesia do the clearing
• Screening Labs/Tests rarely useful
• Should be driven by suspicions from eval/hx
• Perioperative beta blockers decrease mortality
  A Rec. Cochrane

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Links

• Articles
• http//www.acc.org/clinical/guidelines/perio/updat
  e/periupdate_index.htm
• http//www.aafp.org/afp/20040415/poc.html
• http//www.americanheart.org/presenter.jhtml?ident
  ifier1960
• Smetana, Gerald W. in http//uptodateonline.com/u
  td/content
• Flood C Fleisher L. AFP200775656-65.
• forms
• http//www.aafp.org/afp/20040415/pocform.html
• http//uptodateonline.com/utd/content/image.do?ima
  geKeyprim_pix/preop_pa.gif

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• EXTRAS

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Indications for Ambulatory ECG for ischemia
monitoring

• Class I None
• Class IIa
• Patients with suspected variant angina
•  
• Class IIb
• Evaluation of patients with chest pain who cannot
  exercise
• Preoperative evaluation for vascular surgery of
  patients who cannot exercise
• Patients with known CAD and atypical chest pain
  syndrome
• Class III
• Initial evaluation of chest pain patients who are
  able to exercise
• Routine screening of asymptomatic subjects
• source http//www.americanheart.org/presenter.j
  html?identifier1925

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Labs (contd)

• Lytes
• History/medication use more useful
• BUN/Cr
• Reasonable over 50
• Major surgery
• Hypotension expected
• Nephrotoxic meds anticipated

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Labs (contd)

• FBS/FBG/FSG or just serum glucose
• Not recommended for screening
• Recent control hx imperative for diabetics
• LFT only if history/exam suggest disease
• PT/PTT low correlation of abnl to postop comp.
• perfectly unhelpful predictor
• likelihood ratio 0.0
• -likelihood ratio 1.01

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Labs (contd)

• UA
• ? id renal disease or UTI?
• Serum Cr would id renal dz
• UTIs may contribute to 4-5 post-op
  infections/year
• Non-prosthetic knee operations
• 1.5 million per infection prevented!
• Post-op infection adds 3000

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Perioperative Management Cardiac Devices

• Implantable Defibrillators
• Can fire due to activation by stray electrical
  current from electrocautery use
• Must be programmed OFF preoperatively and then
  reactivated postoperatively
• Place defibrillator patches intraoperatively
• Telemetry monitoring is indicated postoperatively
  until the AICD has been reactivated.

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Perioperative Management Cardiac Devices

• Pacemakers

Recommendations Obtain information
preoperatively regarding the pacer manufacturer,
model and serial number, battery status,
and most recent interrogation. If the
pacer is programmed in a rate-responsive mode,
this feature should be inactivated
preoperatively. If a patient is
pacer-dependent, temporary reset to a non-sensing
mode preoperatively may be indicated.
Operative techniques to minimize stray current
(short electrocautery strokes, placement
of electrocautery grounding pad away from pacer
pocket).
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Perioperative ManagementPercutaneous
Intervention (PCI)

• No randomized trials have demonstrated benefit of
  balloon angioplasty or stenting in decreasing
  cardiac risk before non-cardiac surgery.
• Posner KL, et al (1999) Anesth Analg 89553
• No reduction in early postoperative MI or death
  in patients who underwent PTCA.
• Study was not controlled for severity of CAD,
  differences in medical management between the
  groups, or comorbidity.

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Hematologic Risks

• Complications
• Thromboembolic
• Bleeding

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Whos at Risk

• Polycythemia vera
• Thrombocytopenia
• Risk Assessment
• Hematocrit
• Platelet count
• Bleeding time
• PT/PTT

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Risk Management

• Phlebotomy to decrease hct lt 45
• Maintain plts gt 50,000

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Source http//uptodateonline.com/utd/content/imag
e.do?imageKeyprim_pix/preop_pa.gif
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Source AAFP 15 April 2004
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Pre-op eval take home

• Screening questionnaire
• Exercise tolerance
• Blood pressure and pulse
• H P if above abnl, pt gt60y or major surgery
• HCG for young women
• HCT for bloody surgery
• Serum Cr for major surg/ possible hypotension/
  nephrotoxic meds/ pt gt 50

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Clinical Predictors
Major Clinical Predictors?
Intermediate or Minor Clinical Predictors?
Further evaluation
Exercise Tolerance?
Poor Exercise Tolerance lt 4 METS
Good Exercise tolerance gt 4 METS
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Minor or No Clinical Predictors
Poor Exercise Tolerance lt 4 METS
Good Exercise tolerance gt 4 METS
High risk procedure
Intermediate or low risk procedure
Non-invasive cardiac testing
Low risk
High risk
O. R.
Further evaluation
69
Intermediate clinical predictors
Poor Exercise Tolerance lt 4 METS
Good Exercise tolerance gt 4 METS
High risk procedure
Intermediate risk procedure
Low risk procedure
Non-invasive cardiac testing
High risk
Low risk
O. R.
Further evaluation
70
Preoperative Stress Testing
Y
Major clinical predictors?
Further evaluation
N
N
2 or more of the following Intermediate
clinical predictors Poor exercise
tolerance lt 4 METS High risk surgery
O.R.
Y
Patient ambulatory and can exercise?
Test ONLY if outcome will impact management
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Patient ambulatory and can exercise?
Y
N
Male, normal ECG at rest?
Bronchospasm? Second degree AV block? Theophylline
dependent? Valvular dysfunction?
N
Y
ECG ETT
ETT Echo or Perfusion scan
Y
N
Pharmacological Echo or Perfusion Scan
Prior symptomatic arrhythmia? Poor Echo
window? Extreme blood pressure?
Hx Arrhythmias? Severe HTN?
N
Y
Y
N
Persantine or Adenosine Perfusion Scan
Dobutamine Echo or Perfusion Scan
Further evaluation