Preoperative Assessment

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Introduction

Preoperative assessment is an important component of surgical care, to ensure risk factors are identified and optimized, and physiologic function is maximized.

In some situations, eg emergency surgery, the opportunity to intervene is diminished, but identification of risk factors that could lead to potential complications should still be considered and addressed as best as possible.

 

Surgical type can be associated with increased cardiac stress due to a number of factors:

 

The American Heart Association (AHA) has classified surgeries according to high, medium, and low risk (Fleisher et al, 2007):

Vascular (cardiac risk at or above 5%)

  • Aortic and other major vascular surgeries
  • Peripheral vascular surgery

Intermediate (cardiac risk 1-5%)

  • abdominal surgery
  • orthopedic surgery
  • intrathoracic surgery
  • head and neck surgery
  • carotid endarterectomy
  • prostate surgery

Low (cardiac risk<1%)

  • superficial procedures
  • breast surgery
  • endoscopy
  • cataract procedures

 

 

The American Society of Anesthesiologists Classification of Perioperative Mortality provides further guidance on risk.

ASA I: healthy patient

ASA II: mild systemic disease; well-controlled. No functional limitations

ASA III: moderate to severe disease, with some functional limitation

ASA IV: severe, life-threatening systemic disease, functionally incapacitated

ASA V: patient near death; not expected to survive for 24 hours

ASA VI: brain-dead patient, for organ donation

E: denotes emergency surgery

 

 

 

 

History

The goal of pre-operative assessment is to identify patients with cardiac or other disease that place them at high risk. These underlying conditions should be explored regarding their severity and control.

 

A review of systems should include:

Specific past medical history questions should include:

 

Evidence of current or recent infection should be queried.

 

Assess nutritional status.

 

Inquire into medications, specifically:

 

Ask abour Smoking, alcohol, and illegal drug use. Withdrawal from alcohol or other substances can significantly complicate post-operative recovery.

 

 

 

Physical Exam

The physical exam should focus on overall fitness, as well as signs of systemic disease. The following components should be considered:

 

 

Investigations

While approaches vary according to institution, the following acts as a general guide:

CBC

  • menstruating female
  • history of anemia or polycythemia
  • surgery with suspected blood loss

urine pregnancy test

 

electrolytes, glucose, and creatinine

  • patients over 50
  • dieuretic therapy
  • diabetes
  • chronic renal disease
  • chronic liver disease
  • chronic diarrhea
  • steroid therapy

liver tests

  • liver disease
  • cancer

PT/PTT/platelet count

  • history of abnormal bleeding
  • anticoagulant therapy
  • liver disease

ECG

  • as described below

 

CXR

  • active lung disease

 

Type and Cross

  

 

 

Specific System Considerations

  • cardiovascular
  • respiratory
  • renal
  • hepatic
  • metabolic

Cardiovascular Function

The following cardiac recommendations are a summary of the 2007 ACC/AHA guidelines, published in (Fleisher et al, 2007):

 

Echocardiography

Ejection fraction below 35% is a serious contraindication for surgeries noncardiac in nature; perioperative MI rates are over 75%.

 

Left ventricular function should be assessed by echocardiogram in the following settings:

  • undiagnosed shortness of breath
  • history of heart failure with worsening symptoms

Routine echocardiogram is not recommended.

 

 

ECG

ECG can be helpful in identifying unknown cardiac abnormalities, such as Q waves (previous MI), left ventricular hypertrophy, or arrhythmias such as atrial fibrillation.

ECG should be performed within 30 days of surgery if:

  • patients are undergoing vascular surgery with a cardiac risk factor
  • patients are undergoing intermediate surgery with a history of heart disease, peripheral vascular disease, or cerebrovascular disease
  • ECG should be considered if patients are undergoing intermediate surgery with a cardiac risk factor

Asymptomatic patients undergoing low-risk surgery do not need ECG.

 

 

Stress testing

Stress testing can provide additional information about cardiac and functional capacity as warranted.

It should be performed if:

  • patients have active, poorly controlled cardiac conditions
  • patients undergoing vascular surgery have poor functional capacity and at least three risk factors

It should be considered if:

  • patients undergoing vascular surgery have good functional capacity and at least one risk factor
  • patients undergoing intermediate-risk surgery have poor functional capacity and at least one risk factor

 

 

Goldman's index of cardiac risk assigns risk points based upon:

  • congestive heart failure (worst)
  • recent MI
  • PVCs
  • arrhythmias
  • age over 70
  • emergency nature of surgery
  • aortic valvular stenosis

Respiratory Function

Smoking is the biggest threat to pulmonary function due to impaired ventilation (high pCO2 and low FEV1).

Smoking cessation and respiratory therapy should be strongly encouraged 8 weeks prior to surgery.

Renal Function

Hepatic Function

Mortalilty is increased with increased serum bilirubin or PTT, decreased albumin, or hepatic encaphalopathy.

Metabolic Function

Hyperglycemia must be controlled prior to surgery.

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Pre-Operative Letter

The pre-op letter should reflect important characteristics. These include:

 

 

Medications

Most medications should be taken prior to surgery. The following exceptions should be noted:

Beta blockers may be considered if cardiac ischemia is anticipated.

 

 

Resources and References

Fleisher LA et al. 2007. ACC/AHA guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 116(17):e425.

Graham L. 2008. ACC/AHA Release Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery.

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