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Preoperative Evaluation

by Robert G. Johnson, MD

If an emergency procedure is required, preoperative evaluation must be rapid and is thus limited. In other cases, the surgical team may consult an internist to obtain a formal preoperative evaluation, which helps minimize risk by identifying correctable abnormalities and by determining whether additional monitoring is needed or whether a procedure should be delayed so that an underlying disorder (eg, hypertension, hyperglycemia, hematologic abnormalities) can be controlled optimally.

Routine preoperative evaluation varies substantially from patient to patient, depending on the patient’s age, general health, and risks of the procedure.


A relevant preoperative history includes information about all of the following:

  • Current symptoms suggesting an active cardiopulmonary disorder (eg, cough, chest pain, dyspnea during exertion, ankle swelling) or infection (eg, fever, dysuria)

  • Risk factors for thromboembolism (see Deep Venous Thrombosis (DVT)), excessive bleeding (see Excessive Bleeding), or infection

  • Known disorders that increase risk of complications, particularly hypertension, heart disease, kidney disease, liver disease, diabetes, asthma, COPD, and bleeding disorders

  • Previous surgery, anesthesia, or both, particularly their complications

  • Allergies

  • Tobacco and alcohol use

  • Current prescription and nonprescription drug and supplement use

If an indwelling catheter may be needed, patients should be asked about prior urinary retention and prostate surgery.

Physical examination

Physical examination should include not only areas affected by the surgical procedure but also the cardiopulmonary system and a search for any signs of ongoing infection (eg, upper respiratory tract, skin). When spinal anesthesia is likely, patients should be evaluated for scoliosis and other anatomic abnormalities that may complicate lumbar puncture. Any cognitive dysfunction, especially in elderly patients who will be given a general anesthetic, should be noted. Preexisting dysfunction may become more apparent postoperatively and, if undetected beforehand, may be misinterpreted as a surgical complication.


No preoperative tests are required in healthy patients undergoing operations with very low risk of significant bleeding or other complications; abnormal results are more likely to be false positives than in patients with symptoms or risk factors. In symptomatic patients or in patients undergoing operations with a higher risk of significant bleeding or other complications, laboratory evaluation may include the following tests:

  • CBC and urinalysis (glucose, protein, and cells) usually are done.

  • Serum electrolytes and creatinine and plasma glucose are measured unless patients are extremely healthy and < 50 yr of age, the procedure is considered very low risk, and use of nephrotoxic drugs is not expected.

  • Liver enzymes are measured if abnormalities are suspected based on the patient’s history or examination.

  • Coagulation studies and bleeding time are needed only if patients have a history of bleeding diathesis or a disorder associated with bleeding.

  • ECG is done for patients at risk of coronary artery disease, including all men > 45 and women > 55.

  • If a general anesthetic is to be used, a chest x-ray typically is done (or a recent x-ray is reviewed), although its usefulness is limited, particularly in younger patients and in patients without suspicion of heart or lung disease.

  • Pulmonary function testing may be done if patients have a known chronic pulmonary disorder or symptoms or signs of pulmonary disease.

Patients with symptomatic coronary artery disease need additional tests (eg, stress testing, coronary angiography) before surgery.

Surgical risk factors

Surgical risk varies with patient risk factors and the procedure.

Procedural risk is highest with the following:

  • Heart or lung surgery

  • Prostatectomy

  • Major orthopedic procedures (eg, hip replacement)

Patients undergoing elective surgery that has a significant risk of hemorrhage should consider autologous transfusion (see Blood Collection). Autologous transfusion decreases the risks of infection and transfusion reactions. Emergency surgery also has a higher risk of morbidity and mortality.

Patient risk factors are stratified by some clinicians using published criteria (see Cardiac Risk Index in Noncardiac Surgery). Older age is associated with decreased physiologic reserve and greater morbidity if a complication occurs. However, chronic disorders are more closely associated with increased postoperative morbidity and mortality than is age alone. Older age is not an absolute contraindication to surgery.

Cardiac risk factors dramatically increase surgical risk. Among the most serious are the following:

  • Unstable angina

  • Recent MI

  • Poorly controlled heart failure

When a heart disorder cannot be corrected before surgery, intraoperative and sometimes preoperative monitoring with pulmonary artery catheterization may be advised.

Cardiac Risk Index in Noncardiac Surgery




Age (yr)



Cardiac status

MI within 6 mo


Ventricular gallop or jugular venous distention (signs of heart failure)


Significant aortic stenosis


Arrhythmia other than sinus or premature atrial contractions


5 premature ventricular contractions/min


General medical condition

P o 2 < 60 mm Hg, P co 2 > 50 mm Hg, K < 3 mmol/L, HCO 3 < 20 mmol/L, BUN > 50 mg/dL, serum creatinine > 3 mg/dL, elevated AST, a chronic liver disorder, or bedbound


Type of operation needed



Intraperitoneal, intrathoracic, or aortic


*Risk is based on the total number of points:

Level I: 0–5

Level II: 6–12

Level III: 13–25

Level IV: >25

Adapted from Goldman L, et al: Multifactorial index of cardiac risk in noncardiac surgical procedures. New England Journal of Medicine 297:845–850, 1977.

Incidental infections (eg, UTIs) should be treated with antibiotics but should not delay surgery unless prosthetic material is being implanted; in such cases, incidental infections should be controlled or eliminated before surgery if possible.

Fluid and electrolyte imbalance should be corrected before surgery if possible. Dehydration should be treated with IV normal saline because BP tends to fall when anesthesia is induced. K deficiencies should be corrected to reduce risk of arrhythmias.

Undernutrition (see Undernutrition) increases surgical risk. For example, serum albumin < 2.8 g/dL is associated with increased morbidity and mortality. If surgery can be delayed for several weeks, sometimes nutritional deficiencies are correctable. Usually, the patient’s calorie and protein intake should be increased during the perioperative period. Obesity is unlikely to be correctable in the time available.

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