Test yourself: Preoperative evaluation


Case 1: Hip replacement

A 60-year-old man undergoes preoperative evaluation before total hip replacement surgery. His history includes asthma and obstructive sleep apnea (OSA) but no known coronary artery disease. He also has osteoarthritis of the knee, which does not allow him to walk far without pain, although he is able to perform yard activities that do not require much walking, such as weeding, pruning trees and splitting wood. His medications include flunisolide, salmeterol and albuterol as needed. He also uses positive continuous airway pressure at night.

On physical examination, the BMI is 31 kg/m2. Blood pressure is normal, and oxygen saturation is 90% on room air. Scattered wheezes are heard on pulmonary examination. The remainder of the examination is unremarkable.

Which of the following preoperative strategies will most reduce this patient's risk for postoperative pulmonary complications?

A. Five percent weight loss
B. Improved asthma control
C. Surgical correction of OSA
D. Preoperative spirometry

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Case 2: Laparoscopic cholecystectomy

A 55-year-old woman undergoes preoperative evaluation before elective laparoscopic cholecystectomy. The medical history includes three pregnancies and full-term deliveries with no complications or health problems in the mother or the neonate. She also has an allergy to trimethoprim–sulfamethoxazole. She has had no previous surgeries, problems with prolonged bleeding after tooth extractions or episodes of epistaxis. Her last menstrual period was 18 months ago. She does not smoke and drinks one to two glasses of wine with dinner a few times weekly. The physical examination is normal.

Which of the following is the best approach to preoperative laboratory screening in this patient?

A. Complete blood count (CBC)
B. CBC and international normalized ratio (INR)
C. CBC, INR, prothrombin time (PT) and partial thromboplastin time (PTT)
D. CBC, INR, PT, PTT and bleeding test

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Case 3: Surgical resection

A 68-year-old man recently diagnosed with adenocarcinoma of the cecum undergoes preoperative evaluation before surgical resection. His medical history also includes inoperable coronary artery disease, heart failure with a left ventricular ejection fraction of 35%, hypertension and hyperlipidemia. Angina is stable, occurring approximately monthly, and he has no orthopnea or paroxysmal nocturnal dyspnea. Medications include lisinopril, carvedilol, furosemide, simvastatin and daily aspirin. He plays golf weekly, using a cart, walks two miles three to four times weekly and carries groceries up a flight of stairs to his apartment.

On physical examination, the pulse rate is 64 beats/min and blood pressure is 120/64 mm Hg. Jugular venous pressure is 6 cm. On cardiopulmonary examination, the lungs are clear to auscultation, the heart is regular without an S3 and there is no peripheral edema. Laboratory studies, including CBC, serum electrolyte levels and renal function, are normal. The electrocardiogram is unchanged, with a normal sinus rhythm and evidence of old inferior infarction.

Which of the following is the most appropriate next step in the preoperative evaluation of this patient?

A. Plasma B-type natriuretic peptide measurement
B. Echocardiography
C. Exercise stress testing
D. Nuclear imaging for left ventricular ejection fraction
E. No further evaluation

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Case 4: Arthroscopic knee repair

A 45-year-old man undergoes preoperative evaluation before elective arthroscopic knee repair of a sports-related injury. His medical history includes hypertension treated with atenolol, hydrochlorothiazide and daily aspirin. He has no bleeding problems associated with prior tooth extractions or an appendectomy he underwent as a teenager, or with any other medical conditions. He has no other medical problems and feels well. He usually drinks one to two glasses of wine with dinner, does not smoke and does not use illicit drugs. Results of laboratory studies performed six months ago, including serum electrolyte levels, creatinine level and lipid profile, were normal.

On physical examination, pulse rate is 64 beats/min and blood pressure is 120/72 mm Hg. The remainder of the physical examination is normal.

Which of the following is the most appropriate approach to preoperative laboratory testing in this patient?

A. Electrocardiography and serum electrolyte and creatinine measurement
B. Chest radiography, CBC and serum electrolyte measurement
C. Electrocardiography, serum electrolyte measurement, CBC and urinalysis
D. CBC, prothrombin time/INR and urinalysis

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Case 5: Abdominal aortic aneurysm

A 68-year-old man undergoes preoperative evaluation before abdominal aortic aneurysm repair. His history is significant for coronary artery disease, hypertension and hyperlipidemia. His medications include lisinopril, hydrochlorothiazide, simvastatin and daily aspirin. He has not had angina since undergoing three-vessel coronary artery bypass grafting four years ago. He plays golf weekly, walking and carrying his clubs on a hilly course, walks two miles in 35 to 40 minutes three to four times weekly and vacuums the house.

On physical examination, the pulse rate is 78 beats/min and the blood pressure is 140/87 mm Hg. The remainder of the examination is unremarkable. Results of electrocardiography are consistent with his most recent electrocardiograph, with evidence of an old inferior infarction. Laboratory studies, including CBC, serum electrolyte level and renal function, are normal.

Which of the following is the most appropriate perioperative management in this patient?

A. Atenolol
B. Exercise stress testing
C. Echocardiography
D. Intraoperative right-heart catheterization

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Answers and commentary

Case 1

Correct answer: B. Improved asthma control.

Patients with uncontrolled asthma or the presence of wheezes have an increased risk for pulmonary complications; therefore, this patient requires improved asthma control before undergoing surgery to avoid such complications. Wheezing confers an increased risk for worsening postoperative bronchospasm and laryngospasm on intubation. Hip and gynecologic surgery do not increase the risk for postoperative pulmonary complications compared with emergency, thoracic, abdominal aortic, other vascular or neck surgery and neurosurgery.

Contrary to traditional belief, obesity does not increase the risk for pulmonary complications. The risk for pulmonary complications in the setting of OSA has not been well studied; current evidence suggests some increased airway risk in the immediate postoperative period, so there is no need to delay the hip replacement to evaluate the patient for surgical correction of OSA. Preoperative spirometry is helpful in the diagnosis of obstructive pulmonary disease, but it does not predict the risk for pulmonary complications better than clinical evaluation alone and would therefore not change the management of this patient.

Key point

  • Patients with uncontrolled asthma or the presence of wheezes have an increased risk for postoperative pulmonary complications.

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Case 2

Correct answer: A. Complete blood count (CBC)

Given the patient's history of multiple pregnancies and deliveries and only recent perimenopausal status, available evidence indicates it is reasonable to perform a CBC to rule out anemia in this patient before she undergoes major abdominal surgery. This healthy patient has had no bleeding difficulties associated with prior surgery, childbirth, or tooth extraction or history of epistaxis or alcohol abuse; therefore, preoperative screening for coagulopathy is not indicated. The INR, PT, PTT and bleeding test are not indicated in this patient. The bleeding test, a test of platelet function, is notoriously imprecise and does not correlate with bleeding problems or add information to results of other hematologic tests.

Key point

  • Healthy patients with no history of bleeding difficulties, epistaxis or alcohol abuse do not require coagulopathy screening before major abdominal surgery.
  • Performing a routine CBC is reasonable in women who are premenopausal or only recently perimenopausal to rule out anemia before major abdominal surgery.</div>

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Case 3

Correct answer: E. No further evaluation

Heart failure is as significant a cardiac risk factor as ischemic disease. The recently validated Revised Cardiac Risk Index assigns one point each for a history of the following six variables: high-risk surgery, history of ischemic heart disease, history of congestive heart failure, history of cerebrovascular disease, diabetes treated with insulin, and serum creatinine level greater than 2.0 mg/dL (>176.84 µmol/L). According to their score, patients fall into one of four risk strata: 0, 1, 2 or 3 or more points. This patient has excellent exertional capacity (able to achieve and sustain >4 metabolic equivalents [METS]), but his Revised Cardiac Risk Index score is 3 as indicated by the presence of ischemic heart disease and ischemic cardiomyopathy in the setting of a high-risk procedure. Nonetheless, patients with compensated, asymptomatic heart failure can generally proceed to surgery if the level of other risk factors is acceptable. In patients with stable, infrequent angina and compensated heart failure, no further preoperative testing of left ventricular function with echocardiography or nuclear imaging and stress testing is indicated. The role of plasma B-type natriuretic peptide measurement in preoperative risk assessment is currently undefined.

Key point

  • Patients with compensated asymptomatic heart failure can generally proceed to surgery if the level of other risk factors is acceptable.</div>

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Case 4

Correct answer: A. Electrocardiography and serum electrolyte and creatinine measurement

Although many practitioners and hospital guidelines prefer a broad battery of preoperative tests, the evidence-based standard is selective testing based on the patient's medical history, physical examination and risk for surgery-specific blood loss. Multiple studies have shown that indiscriminate preoperative testing rarely identifies clinically important abnormalities, delays surgery or predicts complications. Abnormal test results often are ignored by clinicians or prove to be false-positive results.

Electrocardiography is indicated in men older than 40 years of age; women older than 50 years of age (based on the median age of menopause in the U.S.); and patients with known coronary artery disease, diabetes mellitus, or other significant risk factors for coronary artery disease, such as hyperlipidemia, family history of coronary artery disease at a young age and hypertension. Measurement of serum electrolytes and creatinine is indicated because of this patient's history of hypertension and diuretic therapy. Chest radiography is not indicated because the patient does not smoke, is younger than 50 years of age, has no respiratory symptoms and is physically active. A CBC is not necessary because anticipated blood loss is minimal for the planned procedure. Coagulation studies are not warranted because the patient has no history of bleeding difficulties. Because the patient has no urinary symptoms, preoperative urinalysis is not necessary. One well-constructed study has determined that tests performed within four months do not need to be repeated if medications or clinical status has not changed.

Key point

  • The evidence-based standard is selective preoperative testing based on medical history, physical examination and risk for surgery-specific blood loss.
  • Multiple studies have shown that indiscriminate preoperative testing rarely identifies clinically important abnormalities, delays surgery or predicts complications.</div>

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Case 5

Correct answer: A. Atenolol

This patient meets the criteria for perioperative cardioprophylaxis with a ß-blocker. This patient has excellent exertional capacity because he is able to achieve and sustain more than 4 METS, but his Revised Cardiac Risk Index score of 2, determined by the presence of ischemic heart disease and coronary artery disease in the setting of a high-risk procedure, indicates that he has a high risk for postoperative cardiac complications.

If there is no contraindication, patients with coronary artery disease or significant risk factors should take perioperative ß-blockers, titrated to a resting heart rate of 60 beats/min. Patients not already taking ß-blockers who meet the criteria for perioperative ß-blocker therapy may also meet the criteria for long-term use of these drugs. ß-Blockers should be titrated over 7 to 10 days before surgery; if this is not feasible, these drugs can be quickly titrated up preoperatively and intraoperatively. If patients do not meet criteria for long-term ß-blocker therapy, this medication may be withdrawn 7 to 10 days postoperatively if they are doing well and ambulating.

Neither stress testing nor echocardiography is indicated in this patient because he does not require further risk stratification before high-risk surgery, he is clinically stable without evidence of new or worsening ischemia and it has been five years or less since revascularization. In a well-done randomized trial, perioperative right-heart catheterization did not reduce perioperative cardiac morbidity and mortality in high-risk surgical patients.

Trials of perioperative ß-antagonists have studied a range of drugs and intravenous or oral regimens; it is not clear whether the cardioprotective effects of these agents are drug-specific (atenolol, bisoprolol) or a class effect. Recent studies suggest that the benefit of ß-blockers is not yet fully elucidated. Although several small meta-analyses of 5 to 11 trials consistently found benefit with the perioperative use of ß-blockers, a recent meta-analysis of 22 trials found no benefit in total mortality, cardiovascular mortality or nonfatal myocardial infarction and found benefit only for a composite outcome of major perioperative cardiac complications (risk reduction, 0.44 [95% CI, 0.20 to 0.97]). Additionally, a large retrospective cohort study of major noncardiac surgery found ß-blockers to be associated with reduced hospital mortality in patients with Revised Cardiac Risk Index scores of 2 or higher, no benefit in patients with a score of 1 and increased mortality in patients with a score of 0.

Key point

  • If there is no contraindication, patients with coronary artery disease or significant risk factors should take perioperative ß-blockers, titrated to a resting heart rate of 60 beats/min.</div>